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Pest Management Science

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ISSN (Print) 1526-498X - ISSN (Online) 1526-4998
Published by John Wiley and Sons

[1586 journals]

Research on the changes in wettability of rice(Oryza sativa.) leaf surfaces in different development stages by OWRK method
- Authors: Yan‐qiu Zhu; Chun‐xin Yu, Yu Li, Qing‐qing Zhu, Lu Zhou, Chong Cao, Ting‐ting Yu, Feng‐pei Du
  Pages: n/a - n/a
  Abstract: Background A good knowledge in wetting behavior of pesticide spray liquid on plant surface is crucial to spray applications. Difference in leaf surface wettability would result in obvious changes in spray wetting behavior. The aim of this paper is to obtain the changes of wettability during different growth periods. Results The contact angle of rice leaf for each liquid increased with rice growth. No significant difference was found between cultivars. The contact angle was found to be correlated with the polar component of liquid surface tension. The square of the polar component was also found to be highly significant indicating that the relationship between these two properties was not a simple linear one. The surface energy of each plant surface decreased as the plants aged. This was also true of each part of the surface energy. However, no obvious difference on the proportion of the components was found among different cultivars and stages. Conclusions The changes in value of CA and SFE both reflect the changes of the leaf surface wettability, while the SFE value shows better in wettability characterizing. Obvious rice leaf wettability changes were found on different development stages, which may be beneficial for researches in agrochemical sprays wetting and spreading behavior. Factors influencing these alterations were discussed.
  PubDate: 2013-06-13T13:08:01.698504-05:
  DOI: 10.1002/ps.3594
Laboratory evaluation of alternative control methods against the false tiger, Monosteira unicostata (Hemiptera: Tingidae)
- Authors: Ismael Sánchez‐Ramos; Susana Pascual, Aránzazu Marcotegui, Cristina E. Fernández, Manuel González‐Núñez
  Pages: n/a - n/a
  Abstract: Background Monosteira unicostata is an important pest of almond tree in the Mediterranean region requiring control methods alternative to synthetic pesticides. The efficacy of kaolin, azadirachtin and potassium salts of fatty acids combined with thyme essential oil against adults and fourth instar nymphs of this tingid was evaluated in laboratory assays. Results In no choice assays with adults, kaolin significantly increased mortality compared to control (42.7% vs 23.8%) and reduced the oviposition of females (11.8 vs 35.3 eggs), the feeding activity (169.6 vs 471.2 excrements) and the damage caused (1.1 vs 2.3 damage index). In choice assays with adults, the repellence index calculated for kaolin (48.2%) was significantly higher compared to control (−15.3%), resulting in oviposition, feeding and damage deterrence indices also significantly higher than the control. In no choice assays with nymphs, all products increased mortality and reduced the feeding activity and the damage caused on leaves. Potassium soap with thyme essential oil and azadirachtin were the most effective compounds (98.0% and 97.6% mortality vs 13.3 % control mortality, respectively). Conclusion The products tested have shown high and different efficacy on nymphs and adults of M. unicostata. This activity might be suitable for the practical application of these compounds to control its populations under real field conditions.
  PubDate: 2013-06-13T13:04:16.30581-05:0
  DOI: 10.1002/ps.3593
Detection and molecular characterisation of methyl benzimidazole carbamate resistant Pyrenopeziza brassicae isolates
- Authors: Helen E. Carter; Hans J. Cools, Jonathan S. West, Michael W. Shaw, Bart A. Fraaije
  Pages: n/a - n/a
  Abstract: Background Methyl benzimidazole carbamate (MBC) fungicides are used to control the oilseed rape pathogen Pyrenopeziza brassicae. Resistance to MBCs has been reported in P. brassicae but the molecular mechanism(s) associated with reductions in sensitivity have not been verified in this species. Elucidation of the genetic changes responsible for resistance, hypothesised to be target site mutations in β‐tubulin, will enable resistance diagnostics and thereby inform resistance management strategies. Results P. brassicae isolates were classified as sensitive, moderately resistant or resistant to MBCs. Crossing P. brassicae isolates of different MBC sensitivities indicated that resistance was conferred by a single gene. The MBC‐target encoding gene β‐tubulin was cloned and sequenced. Reduced MBC sensitivity of field isolates correlated with β‐tubulin amino acid substitutions L240F and E198A. The highest level of MBC resistance was measured for isolates carrying E198A. Negative cross‐resistance between MBCs and the fungicides diethofencarb and zoxamide was only measured in E198A isolates. PCR‐RFLP was used to screen isolates for the presence of L240F and E198A. The substitutions E198G and F200Y were also detected in DNA samples from P. brassicae populations after cloning and sequencing of PCR products. The frequencies of L240F and E198A in different P. brassicae populations were quantified by pyrosequencing. There were no differences in the frequencies of these alleles between P. brassicae populations sampled from different locations or after fungicide treatment regimes. Conclusions We have identified the molecular mechanisms affecting sensitivity to MBCs in P. brassicae. Pyrosequencing assays are a powerful tool for quantifying fungicide resistant alleles in pathogen populations.
  PubDate: 2013-06-11T08:52:19.506258-05:
  DOI: 10.1002/ps.3585
Insecticide susceptibilities in populations of two rice planthoppers, Nilaparvata lugens and Sogatella furcifera, immigrating into Japan in the period 2005–2012
- Authors: Masaya Matsumura; Sachiyo Sanada‐Morimura, Akira Otuka, Reiko Ohtsu, Shinji Sakumoto, Hiroaki Takeuchi, Masaru Satoh
  Pages: n/a - n/a
  Abstract: Background The brown planthopper Nilaparvata lugens and the whitebacked planthopper Sogatella furcifera are both important pests on rice throughout Asia. The major cause of recent outbreaks is thought to be the development of insecticide resistance. Thus, we monitored insecticide susceptibilities in populations of these two insects immigrating into Japan in the period 2005–2012. We tested ten insecticides, including members of the organophosphate, carbamate, pyrethroid, neonicotinoid, and phenylpyrazole groups. Results The LD50 values of N. lugens against imidacloprid increased from 2005 (0.7 µg g‐1) to 2012 (98.5 µg g‐1). The resistance ratio (LD50 value in 2012 / baseline LD50 value in 1992) was 615.5. In contrast, LD50 values of N. lugens against fipronil were
  PubDate: 2013-06-10T10:38:35.39854-05:0
  DOI: 10.1002/ps.3590
Evaluation of candidate systems for mass trapping against Ceratitis spp. on La Réunion island
- Authors: I.Esther Peñarrubia‐María; Serge Quilici, Chloé Schmitt, L.Adriana Escudero‐Colomar
  Pages: n/a - n/a
  Abstract: Background Two Ceratitis spp. coexist in the Island of La Réunion, Ceratitis rosa (Karsch) and C. capitata (Wiedemann). The effectiveness of the candidate systems based on attractants and traps to control both species was evaluated through comparative studies of trap types, attractants, insecticides and commercial complete systems. Results The Ceratitis spp. most captured in all trials was C. rosa. Captures of C. rosa and C. capitata were not significantly different when Maxitrap® or Tephri‐trap® were used. Captures with the Easy‐trap® were lower for both species. The BioLure® Med Fly lure showed higher catches of C. rosa than Ferag® CC D TM. The proportion of dead C. rosa did not differ significantly when deltamethrin or dichlorvos were used. There were no significant differences in capturing C. rosa and C. capitata between the commercial systems composed of the lure Ferag® CC D TM, the Maxitrap® and dichlorvos and the BioLure® Unipak, the Tephri‐trap®, and dichlorvos. The Cera Trap® system performed less effectively. Conclusion The most effective traps for the capture of C. rosa and C. capitata were Maxitrap® and Tephri‐trap®; the most effective attractants were BioLure® Med Fly for C. rosa and BioLure® Med Fly, BioLure® Unipak and Ferag® CC D TM for C. capitata. However for both species the most effective commercial combinations of trap and attractant were Maxitrap® with Ferag® CC D TM and Tephri‐trap® with BioLure® Unipak, both using dichlorvos. The insecticide deltamethrin showed good efficacy when used inside traps.
  PubDate: 2013-06-08T08:34:36.156068-05:
  DOI: 10.1002/ps.3591
Research on Practical Parameters of Sex Pheromone Trap for the Oriental Fruit Moth
- Authors: Zhi‐guo Zhao; Er‐hua Rong, Sheng‐Cai Li, Li‐jun Zhang, Wei‐na Kong, Rong‐shan Hu, Jintong Zhang, Rui‐yan Ma
  Pages: n/a - n/a
  Abstract: Background The Oriental fruit moth (OFM) is a worldwide fruit boring insect pest. In China, OFM monitoring traps use a sex pheromone lure, but their overall design is varied. As such, there is a critical need to develop a standardized OFM trap design. In this field study, we examined 10 different trap shapes in varying combinations of colors and sizes (such as trap length and surface area). Results The results showed that there was no significant difference in the trapping efficiency between eight colors. The ship‐shaped trap could kill more OFM in a short period; the automatic watering basin trap could be more effective in the long run. The optimal trapping diameter of basin trap was 25 cm. The trapping efficiency of the triangle traps with the diameters below 10 cm was better than that with the diameters over 30 cm. The trapping number of pasteboard traps obviously declined when the surface area increased and the pasteboard trap with singular board possessed excellent trapping efficiency. Conclusion The results provided useful information in designing standardized sex pheromone traps for monitoring as well as trapping of OFM in the fields.
  PubDate: 2013-06-08T08:33:04.325404-05:
  DOI: 10.1002/ps.3592
Camptothecin‐induced expression of programmed cell death gene 11 in Spodoptera litura
- Authors: Liang Gong; Huidong Wang, Jingfei Huang, Zheng Hu, Meiying Hu
  Pages: n/a - n/a
  Abstract: Background Camptothecin, one of the main active components of extract from the bark of the Chinese camptotheca tree, has been reported as a potent insecticide against various insect species. However, the mechanism of action of camptothecin as a botanical pesticide is not completely understood. Results In this study, the full‐length cDNA (GeneBank No JF681972) of Spodoptera litura programmed cell death protein 11 (pcdp 11) isoform 1 was cloned, sequenced, and characterized. Quantitative real‐time PCR (qRT‐PCR) data showed that pcdp 11 was differentially expressed during the developmental stages, with significantly high expression during the transition from egg to larva and larva to pupa. Furthermore, Pcdp11 was up‐regulated in a time‐dependent manner in SL‐1 cells, after treatment with 1.2 µg mL‐1 camptothecin. The induced expression profile of pcdp 11 in the larval midgut after feeding camptothecin was visualized by fluorescence in situ hybridization (FISH), and further quantified by qRT‐PCR. Apoptosis in camptothecin‐treated larval midguts was confirmed using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. Conclusion Our results reveal a clear functional link between pcdp 11 expression and camptothecin‐induced apoptosis, and prove that camptothecin exhibited strong toxicity toward S. litura by inducing midgut epithelial cell apoptosis.
  PubDate: 2013-06-07T15:36:27.337755-05:
  DOI: 10.1002/ps.3588
Development of a female attractant for the click beetle pest Agriotes brevis
- Authors: József Vuts; Lorenzo Furlan, Éva Bálintné Csonka, Christine M Woodcock, John C Caulfield, Patrick Mayon, John A Pickett, Michael A Birkett, Miklós Tóth
  Pages: n/a - n/a
  Abstract: Background Traps suitable for catching female Agriotes click beetles may provide better reconnaissance than pheromone‐baited traps which catch only males, thereby contributing to more efficient crop protection. The basis for this study came from (i) observations of female Agriotes brevis (Candeze) aggregating beneath foliage of Medicago sativa (L.) and Lolium italicum (A.Br.) placed on plastic sheets on bare soil, and (ii) field tests demonstrating attraction of females to traps baited with foliage from these plants. We aimed to identify and field test volatile compounds from M. sativa and L. italicum leaves. Results A number of electrophysiologically active chemicals were identified from headspace extracts of M. sativa and L. italicum. Three different synthetic blends of the identified compounds, comprising four, seven and nine components, were field‐tested. The four and nine‐component blends caught more female A. brevis than unbaited traps, with the proportion of females not differing between blends. Conclusion The plant‐derived blends were shown to catch female A. brevis under field conditions when applied in traps. Of these, the four‐component blend, due to its relatively simple composition [(Z)‐3‐hexenyl acetate : methyl benzoate : (Z)‐3‐hexen‐1‐ol : methyl salicylate 300:5:30:30 mg/bait], may be a suitable 'standard' blend for bait optimization.
  PubDate: 2013-06-07T15:36:05.381788-05:
  DOI: 10.1002/ps.3589
Suppression of Botrytis cinerea on necrotic grapevine tissues by early season applications of natural products and biological control agents
- Authors: Carlos Calvo‐Garrido; Inmaculada Viñas, Philip AG Elmer, Josep Usall, Neus Teixidó
  Pages: n/a - n/a
  Abstract: Background Necrotic tissues within grape (Vitis vinifera) bunches represent an important source of Botrytis cinerea inoculum for Botrytis bunch rot (BBR) at harvest in vineyards. This research quantified the incidence of B. cinerea on necrotic floral and fruit tissues and the efficacy of biologically‐based treatments for suppression of B. cinerea secondary inoculum within developing bunches. Results At veraison (2009 and 2010), samples of aborted flowers, aborted fruits and calyptras were collected and the incidence and sporulation of B. cinerea determined. Aborted fruits presented significantly higher incidence in untreated samples. Early season applications of Candida sake plus Fungicover®, Fungicover alone or Ulocladium oudemansii, significantly reduced B. cinerea incidence on aborted flowers and calyptras by 46% to 85%, respectively. Chitosan treatment significantly reduced B. cinerea incidence on the calyptras. None of the treatments reduced B. cinerea incidence on aborted fruits. Treatments significantly reduced sporulation severity by 48% or more. Conclusions Treatments were effective at reducing B. cinerea secondary inoculum on necrotic tissues, despite the variable control on aborted fruits. This is the first report that quantifies B. cinerea on several tissues of the bunch trash and describes effective suppression of saprophytic B. cinerea inoculum by biologically‐based treatments.
  PubDate: 2013-06-06T12:20:40.597191-05:
  DOI: 10.1002/ps.3587
Dissipation of Soil Fumigants from Soil Following Repeated Applications
- Authors: Shachaf Triky‐Dotan; Husein A. Ajwa
  Pages: n/a - n/a
  Abstract: Background Dissipation of pesticides in soil and occurrence of accelerated degradation following repeated applications is well known with many pesticides, but much less so with soil fumigants. The fate of various soil fumigants was studied in different agricultural soils following repeated applications of chloropicrin. Results Fumigant dissipation reflected by ∑Concentration x Time (∑CxT) and half‐life values varied widely among the tested soils. Methyl iodide (MI) had the slowest dissipation rate compared with other fumigants in all tested soils. Elimination of biotic agents by soil sterilization prior to MI application did not affect MI concentration in Oxnard soil. Clay content and fumigant dose (∑CxT values) of chloropicrin, 1,3‐dichloropropene and MI were significantly correlated. No significant correlations were found between soil properties and ∑CxT values following metam sodium and methyl bromide (MBr) application. Conclusion The fate of tested soil fumigants is highly dependent on and specific to the fumigant, previous fumigant application and soil type. This study suggests that biotic factors are more essential in the dissipation of metam sodium and MBr than abiotic factors. By contrast, MI dissipation from the tested soils is affected more by abiotic factors than biotic activities.
  PubDate: 2013-06-06T12:20:30.523661-05:
  DOI: 10.1002/ps.3586
Effect of spray angle and spray volume on deposition of a medium droplet spray with air support in ivy pot plants
- Authors: D. Foqué; J. G. Pieters, D. Nuyttens
  Pages: n/a - n/a
  Abstract: Background Spray boom systems, an alternative to the predominantly‐used spray guns, have the potential to considerably improve crop protection management in greenhouses. Based on earlier experiments1,2, the further optimization of the deposits of a medium spray quality extended range flat fan nozzle type using easy adjustable spray boom settings was examined. Using a mineral chelate tracers and water sensitive papers, the spray results were monitored at three plant levels, on the upper side and the underside of the leaves, and on some off‐target collectors. In addition, the deposition datasets of all tree experiments were compared. Results The data showed that the most efficient spray distribution with the medium spray quality flat fan nozzles was found with a 30° forward angled spray combined with air support and an application rate of 1000 L ha‐1. This technique resulted in a more uniform deposition in the dense canopy and increasing spray deposition on the lower side of the leaves compared with the a standard spray boom application. Applying 1000 L ha‐1 in two subsequent runs instead of one did not seem to show any added value. Conclusion Spray deposition can be improved hugely simply by changing some spray boom settings like nozzle type2, angling the spray, using air support and adjusting the spray volume to the crop.
  PubDate: 2013-05-28T12:34:58.03259-05:0
  DOI: 10.1002/ps.3584
Toxicological and biochemical response of the entomopathogenic fungus Beauveria bassiana after exposure to deltamethrin
- Authors: Lucas Forlani; M Patricia Juárez, Sabrina Lavarías, Nicolás Pedrini
  Pages: n/a - n/a
  Abstract: Background The chemical control of the Chagas disease vector Triatoma infestans is endangered by the emergence of pyrethroid resistance. An effective alternative control tool is the use of the entomopathogenic fungus Beauveria bassiana. The effect of deltamethrin on fungal growth, gene expression and enzyme activity in relation to detoxification, antioxidant response and oxidative stress levels was studied to evaluate fungal tolerance to deltamethrin. Results The mean inhibitory concentration (IC50) was 50 µg deltamethrin/cm2. Cytochrome P450 genes were differentially expressed; cyp52X1 and cyp617N1 transcripts were > 2‐fold induced, followed by cyp655C1 (1.8‐fold). Minor effects were observed on genes encoding for other P450s, epoxide hydrolase and glutathione S‐transferase (GST). Superoxide dismutase (SOD) genes showed induction levels ≤ 2, catalase (CAT) and glutathione peroxidase genes were also induced ~ 2‐3‐fold and
  PubDate: 2013-05-28T12:34:19.581367-05:
  DOI: 10.1002/ps.3583
Lactones 43 1 . New biologically active lactones ‐ β‐cyclocitral derivatives
- Authors: Marcelina Mazur; Witold Gładkowski, Magdalena Podkowik, Jacek Bania, Jan Nawrot, Agata Białońska, Czesław Wawrzeńczyk
  Pages: n/a - n/a
  Abstract: Background In our previous studies bicyclic γ‐lactones with cyclohexane ring exhibited high antifeedant activity against storage pests. The activity was correlated with to the type and number of substituents in the cyclohexane ring. One of the most potent group of antifeedant agents was δ‐iodo‐γ‐lactones. Results We present the synthesis of new bicyclic γ‐lactones with the cyclohexane ring containing different halogen atoms. To determine the impact of halogen type on biological activity the lactone without halogen atom was also synthesized. The lactones were tested for their antifeedant activity toward the granary weevil beetle (Sitophilus granarius L.), the khapra beetle (Trogoderma granarium Everts) and the confused flour beetle (Tribolium confusum Du Val.). The results of the tests proved that the highest activity was observed for chlorolactone (7) towards larvae and adults of Tribolium confusum. Antibacterial activity of new lactones was also evaluated. Lactone without halogen atom (8) was active against Staphylococcus aureus and Listeria monocytogenes. Conclusions Studies on the biological activity of synthesized lactones revealed high selectivity towards insect pests as well as bacterial strains. Only the halolactones exhibited significant antifeedant activity. In contrary the antibacterial activity was shown only by the lactone (8) without halogen.
  PubDate: 2013-05-22T11:05:42.51731-05:0
  DOI: 10.1002/ps.3557
Identification of cultivable bacteria in the intestinal tract of Bactrocera dorsalis from three different populations and determination of their attractive potential
- Authors: Hongxiu Wang; Liang Jin, Tao Peng, Hongyu Zhang, Qinglong Chen, Yuejin Hua
  Pages: n/a - n/a
  Abstract: Background To identify the cultivable bacteria inhabiting the intestinal tract of adult oriental fruit flies (Bactrocera dorsalis) from laboratory‐reared, laboratory sterile sugar‐reared, and field‐collected populations, and to evaluate the attractiveness of the metabolites produced by the above bacteria to their hosts. Results Fifteen bacterial isolates chosen from the three populations were determined at species level. These 15 strains were cultured and the attractiveness of the whole LB broth, filtered and autoclaved supernatants to B. dorsalis adults was determined using bioassays. The bioassays showed that all bacterial strains were significantly more attractive to B. dorsalis adults than the media‐only control. Among them, Bacillus cereus, Enterococcus faecalis, Enterobacter cloacae, and Citrobacter freundii were the most attractive bacteria. Furthermore, results of a subsequent field test showed that the six bacterial strains were significantly more attractive than the control, with B. cereus and E. faecalis attracting significantly more flies. Conclusions A cultivable bacterial community composed of Enterobacteriaceae, Enterococcaceae, and Bacillaceae was identified in the intestinal tract of B. dorsalis. Metabolites from B. cereus attracted the greatest number of B. dorsalis adults in the laboratory and field. These results provide useful information for the development of bacterial biocontrol agents or implementation as an insecticide.
  PubDate: 2013-05-20T12:10:27.579678-05:
  DOI: 10.1002/ps.3528
Plant protection in Poland on the eve of obligatory Integrated Pest Management implementation
- Authors: Ewa Matyjaszczyk
  Pages: n/a - n/a
  Abstract: Integrated Pest Management will be obligatory in all EU member states from 01.01.2014. Successful IPM implementation will depend not only on the sound guidelines and goodwill of the farmers, but also on conditions in farmers’ environment. This paper presents the most important factors influencing IPM implementation in Poland. The most favorable aspects on the eve of obligatory IPM implementation are the relatively low use of plant protection products and popularity of some non‐chemical methods of pest control, such as sowing cereal in mixture. The most important challenges are the improvement of advisory service and the crop structure with almost ¾ of sown area covered by cereals.
  PubDate: 2013-05-20T11:59:50.209326-05:
  DOI: 10.1002/ps.3578
High levels of biological activity of Cry1Ac protein expressed on MON 87701 × MON 89788 soybean against Heliothis virescens (Lepidoptera: Noctuidae)
- Authors: Oderlei Bernardi; Patrick M Dourado, Renato A Carvalho, Samuel Martinelli, Geraldo U Berger, Graham P Head, Celso Omoto
  Pages: n/a - n/a
  Abstract: Background Genetically modified MON 87701 × MON 89788 soybean (Glycine max) that expresses the Cry1Ac and EPSP‐synthase proteins is a new Integrated Pest Management (IPM) tool for controlling H. virescens in Brazil. To support Insect Resistance Management (IRM) programs and understand the value of this event for IPM, we conducted laboratory and field studies to assess the biological activity of Cry1Ac protein expressed on Bt soybean against this insect pest. Results H. virescens was highly susceptible to purified Cry1Ac protein [LC50 (FL 95%) = 0.026 (0.021 ‐ 0.033) µg Cry1Ac mL‐1 diet]. In bioassays with freeze‐dried MON 87701 × MON 89788 soybean tissue diluted 25 times in an artificial diet, there was 100% mortality of H. virescens. In bioassays with leaf disc, young trifoliate, flower buds, pods and high artificial infestation under greenhouse condition, MON 87701 × MON 89788 soybean showed a high level of control against H. virescens. Moreover, larvae from first through fifth instar were highly susceptible to MON 87701 × MON 89788 soybean. Conclusions The MON 87701 × MON 89788 soybean provides an effective alternative in controlling H. virescens and complies with the concept of high‐dose for IRM programs.
  PubDate: 2013-05-17T11:51:10.62491-05:0
  DOI: 10.1002/ps.3581
Variation in susceptibility of laboratory and field strains of three stored‐grain insect species to β‐cyfluthrin and chlorpyrifos‐methyl plus deltamethrin applied to concrete surfaces
- Authors: Blossom Sehgal; Bhadriraju Subramanyam, Frank H. Arthur, Bikram S. Gill
  Pages: n/a - n/a
  Abstract: Background The efficacy of commercial formulations of β‐cyfluthrin and chlorpyrifos‐methyl plus deltamethrin applied to clean, concrete surfaces similar to that of empty bins against field strains of stored‐grain insects is unknown. We exposed adults of 16 strains of the red flour beetle, Tribolium castaneum (Herbst); 8 strains of the sawtoothed grain beetle, Oryzaephilus surinamensis (L.); and 2 strains of the lesser grain borer, Rhyzopertha dominica (F.), collected mainly from farm‐stored grain in Kansas, USA, to β‐cyfluthrin and chlorpyrifos‐methyl plus deltamethrin applied to concrete surfaces and determined knockdown and mortality. Results Knockdown and mortality differences among species and strains to the insecticides tested were significant. Mortality of all species was less than that of knockdown, suggesting recovery when placed on food after insecticide exposure. β‐cyfluthrin was effective against R. dominica but ineffective against T. castaneum and O. surinamensis field strains. Chlorpyrifos‐methyl plus deltamethrin was only partially effective against field strains of the three species. Conclusion Reduced susceptibility in field strains may be due to inherent formulation deficiency and low levels of tolerance or resistance to β‐cyfluthrin. No single insecticide provided adequate control of the three species tested.
  PubDate: 2013-05-14T12:07:33.467637-05:
  DOI: 10.1002/ps.3580
Enhance knowledge on sustainable use of Plant Protection Products within the framework of the Sustainable Use Directive
- Authors: Maura Calliera; Fabio Berta, Tiziano Galassi, Floriano Mazzini, Rossana Rossi, Roberto Bassi, Pierluigi Meriggi, Alfredo Bernard, Alex Marchis, Andrea Di Guardo, Ettore Capri
  Pages: n/a - n/a
  Abstract: Background In 2008–2009, a survey in the Emilia Romagna region of Italy collected information on the farm use of Plant Protection Products (PPPs) and evaluated whether the provisions of the Directive for the Sustainable Use of Pesticides are applicable. It was concluded that the provisions can be implemented, even if some gaps need to be filled and also the behaviour of farmers needs to be improved. Moreover, it was observed that all stages in the use of PPPs on farms could generate risks for the operator and/or the environment. One of the recommendations is to promote training for operators and to adopt good agronomic practices in order to improve sustainable use of PPPs. Results The findings were used, in the following years, to develop a Guideline for Sustainable Use of PPPs to help the user in identifying the flaws in current practices at farm level as well as their corresponding corrective actions. The Guidelines are accompanied by free on‐line software to be used as a diagnostic tool as well as to provide recommendations for improvements. Conclusion The approach adopted, taking into account the variability in farm structure, cropping pattern, risk attitude and economic availability, is not an instrument to identify the most suitable protection strategy for a given crop in a given period, but to help professional users to improve their practices in managing PPPs on farms and to make the most appropriate choices leading to reduced environmental and human risk, without compromising the profitability of agricultural production and food standards. This work has, as an underlying principle, a holistic approach to link the different elements of the three pillars of sustainability (environment, economy and society) and to enhance knowledge, which represents one of the main aspects of the Directive
  PubDate: 2013-05-13T12:51:45.353619-05:
  DOI: 10.1002/ps.3579
Vector Control and Foliar Nutrition to Maintain Economic Sustainability of Bearing Citrus in Florida Groves Affected by Huanglongbing
- Authors: Philip A. Stansly; H.Alejandro Arevalo, Jawwad A. Qureshi, Moneen M. Jones, Katherine Hendricks, Pamela D. Roberts, Fritz M. Roka
  Pages: n/a - n/a
  Abstract: Background Huanglongbing (HLB) or citrus greening is a bacterial disease vectored by the Asian citrus psyllid (ACP) causing tree decline, and yield loss. Vector control and foliar nutrition are used in Florida to slow the spread of HLB and mitigate debilitating effects of the disease. A 4 year replicated field study was initiated Feb 2008 in a 5.2‐ha commercial block of young ‘Valencia’ orange trees employing a factorial design to evaluate individual and compound effects vector management and foliar nutriention. Insecticides were sprayed during tree dormancy and when psyllid populations exceeded a nominal threshold. A mixture consisting primarily of micro‐ and macro‐nutrients was applied three times a year corresponding to the principal foliar flushes. Results Differences in ACP numbers of from 5 to 13‐fold were maintained in insecticide treated and untreated plots. Incidence of HLB estimated by PCR, rose from 30% at the beginning of the study to 95% in only18 months. Highest yields all 4 years were seen from trees receiving both foliar nutrition and vector control. Production for these trees in the 4th was close to pre‐HLB regional average for 10 year old ‘Valencia’ on ‘Swingle’. Nevertheless, at current juice prices, the extra revenue generated from the combined insecticide and nutritional treatment did not cover the added treatment costs. Conclusions This experiment demonstrated that vector control, especially when combined with enhanced foliar nutrition, could significantly increase yields in a citrus orchard with high incidence of HLB. Economic thresholds for both insecticide and nutrient applications are needed under different market and environmental conditions.
  PubDate: 2013-05-11T11:37:17.689963-05:
  DOI: 10.1002/ps.3577
Spatial variation in herbicide leaching from a marine clay soil via subsurface drains
- Authors: Barbro M Ulén; Mats Larsbo, Jenny K Kreuger, Annika L Svanbäck
  Pages: n/a - n/a
  Abstract: Background Subsurface transport via tile drains can significantly contribute to pesticide contamination of surface waters. The spatial variation in subsurface leaching of normally applied herbicides was examined together with phosphorus losses in 24 experimental plots with water sampled flow‐proportionally. The study site was a flat, tile‐drained area with 60% marine clay in the topsoil in SE Sweden. The objectives were to quantify the leaching of frequently used herbicides from a tile drained cracking clay soil and to evaluate the variation in leaching within the experimental area and relate this to topsoil management practices (tillage method and structure liming). Results In summer 2009, 0.14, 0.22 and 1.62%, respectively, of simultaneously applied amounts of MCPA, fluroxypyr and clopyralid were leached by heavy rain 5 days after spraying. In summer 2011, on average 0.70% of applied bentazone was leached by short bursts of intensive rain 12 days after application. Peak flow concentrations representing 50% of the treated area for MCPA and 33% for bentazone exceeded the Swedish no‐effect guideline values for aquatic ecosystems. Approximately 0.08% of the glyphosate applied was leached in dissolved form in the one winters of 2008/2009 and 2010/2011. Based on measurements of glyphosate in particulate form, total glyphosate losses were twice as high (0.16%) in a second winter. The spatial inter‐plot variation was great large (72‐115%) for all five herbicides studied, despite small variations (25%) in water discharge. Conclusions The study shows the importance of local scale soil transport properties for herbicide leaching in cracking clay soils.
  PubDate: 2013-05-09T06:08:11.552609-05:
  DOI: 10.1002/ps.3574
Synergistic manipulations of plant and insect defences
- Authors: Georgina Bingham; Selcan Alptekin, Giovanna Delogu, Oktay Gurkan, Graham Moores
  Pages: n/a - n/a
  Abstract: Background It has been demonstrated previously that cis‐jasmone acts as an elicitor of plant defence mechanism(s) by inducing secondary metabolism. It has also been demonstrated that temporal synergism can result in hypersensitive insect pests due to the inhibition of metabolic enzymes. Results Laboratory bioassays demonstrated that pre‐exposure of insects by piperonyl butoxide followed by cis‐jasmone treatment of crops, reduced Aphis gossypii on cotton by 80% and Myzus persicae on sweet pepper by 90%. By microencapsulating the cis‐jasmone and combining with piperonyl butoxide, Bemisia tabaci on tomatoes was reduced by 99%. A field trial with microencapsulated cis‐jasmone combined with piperonyl butoxide resulted in a comparable reduction of whitefly egg numbers to that given by the registered rate of imidacloprid, with efficacy of 89% and 93%, respectively. Conclusions If insect defence enzymes are compromised by piperonyl butoxide whilst plant defence is primed by cis‐jasmone, there are possibilities of an insecticide‐free method of controlling insect pests. The success seems largely dependent upon the toxicity of the plants’ secondary chemistry.
  PubDate: 2013-05-07T12:48:10.3766-05:00
  DOI: 10.1002/ps.3575
Residual And Pretreatment Application Of Starycide Insect Growth Regulator (Triflumuron) To Control Aedes Aegypti In Containers
- Authors: Susan P. Jacups; Christopher J. Paton, Scott A. Ritchie
  Pages: n/a - n/a
  Abstract: Background Dengue is not endemic in Australia, although the vector mosquito Aedes aegypti is. In order to prevent dengue establishment, Australia maintains tight control of vector mosquitoes. Tight control programs often necessitate regular repeat application of treatments, and this is resource intensive. We sought to investigate the efficacy and longevity of triflurumon Starycide® Insect Growth Regulator under field conditions in tropical Australia against Aedes. We compared two doses (0.48 and 0.96 ppm), applied to water receptacles with delayed flooding by 0, 2, and 4 weeks. Results We found greater than 90% inhibition of pupae development was achieved for up to 12 weeks. A dose of 0.96ppm, when delayed for 2 or 4 weeks before flooding, provided 50 times inhibition relative to controls, for up to 22 weeks, suggesting triflumuron bound to the plastic substrate and offered a greater residual effect than applications without delayed flooding. Conclusions We conclude that triflurumon offers excellent efficacy and longevity against Aedes in artificial containers. If deployed under standard conditions, reapplication may not be required for up to 22 weeks, furthermore, initial applications could be performed under dry conditions, and this application method may improve the residual effects.
  PubDate: 2013-05-07T12:48:02.330363-05:
  DOI: 10.1002/ps.3576
Cytochrome P450 genes induced by bispyribac‐sodium treatment in a multiple‐herbicide resistant biotype of Echinochloa phyllopogon
- Authors: Satoshi Iwakami; Akira Uchino, Yukiko Kataoka, Hiroyuki Shibaike, Hiroaki Watanabe, Tatsuya Inamura
  Pages: n/a - n/a
  Abstract: Background Incremental herbicide metabolism by cytochrome P450 monooxygenases (P450) has been proposed as the basis for resistance to bispyribac‐sodium (bispyribac) in a multiple‐herbicide resistant biotype of Echinochloa phyllopogon. Upon exposure to bispyribac, strong induction of bispyribac‐metabolizing P450 activity has been reported in the resistant line, indicating P450s induced by bispyribac are involved in the bispyribac resistance. Results We used a PCR‐based cloning strategy and isolated 39 putative P450 genes from the bispyribac‐resistant line of E. phyllopogon. Expression analysis by real‐time PCR revealed that seven of the isolated genes were up‐regulated in response to bispyribac treatment of seedlings at the three‐leaf stage. The transcript levels and protein sequences of the seven genes were compared between the bispyribac‐resistant line and a susceptible line. CYP71AK2 and CYP72A254 were transcribed prominently in the bispyribac‐resistant line. Amino acid polymorphisms were found in three genes including CYP72A254. Conclusion Up‐regulated expression of these genes is consistent with the inducible herbicide‐metabolizing P450 activity under bispyribac stress reported in the previous study. This is the first study comparing P450 genes in arable weed species to elucidate the mechanism for P450‐mediated herbicide resistance.
  PubDate: 2013-05-06T08:04:08.615186-05:
  DOI: 10.1002/ps.3572
Genetic toxicity of dillapiol and spinosad larvicides in somatic cells of Drosophila melanogaster
- Authors: Eliezer H Pires Aciole; Nilza N Guimarães, Andre S Silva, Erima M Amorim, Sergio M Nunomura, Ana Cristina L Garcia, Kênya S Cunha, Claudia Rohde
  Pages: n/a - n/a
  Abstract: Background Higher rates of diseases transmitted from insects to humans led to the increased use of organophosphate insecticides, proven to be harmful to human health and the environment. New, more effective chemical formulations with minimum genetic toxicity effects have become the object of intense research. These formulations include larvicides derived from plant extracts like dillapiol, a phenylpropanoid extracted from Piper aduncum, and from microorganisms like spinosad, formed by spinosyns A and D derived from the Saccharopolyspora spinosa fermentation process. This study investigated the genotoxicity of dillapiol and spinosad, characterizing and quantifying mutation events and chromosomal and/or mitotic recombination using the Somatic Mutation and Recombination Test (SMART) in wings of Drosophila melanogaster. Results 72‐day‐old standard cross (ST) larvae were treated with different dillapiol and spinosad concentrations. Both compounds presented positive genetic toxicity, mainly as mitotic recombination events. Distilled water and doxorubicin (DXR) were used as negative and positive controls, respectively. Conclusion Spinosad was 14 times more genotoxic than dillapiol, and the effect was found to be purely recombinogenic. However, more studies on the potential risks of insecticides such as spinosad and dillapiol are necessary based on other experimental models and methodologies to ensure safe use.
  PubDate: 2013-05-06T07:57:25.068121-05:
  DOI: 10.1002/ps.3573
Toxicity risk of insecticides to the insect egg parasitoid Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae)
- Authors: Yanhua Wang; Changxing Wu, Liping Chen, Lizhi Yang, Weihua Yu, Xueping Zhao, Qiang Wang, Leiming Cai
  Pages: n/a - n/a
  Abstract: Background Natural populations of T. evanescens contribute to the control of Lepidopterous pests. The toxic effects of insecticides have been extensively reported on trichogrammatids, but are largely unknown on T. evanescens. In this study, the toxicities of seven classes of chemicals against the parasitoid were investigated. Results Among them, organophosphates and carbamates exhibited the highest levels of intrinsic toxicity with LC50 values ranging from 0.025 (0.023‐0.028) to 2.20 (1.71‐3.09) and from 0.040 (0.032‐0.053) to 1.84 (1.53‐2.30) mg a.i.·L‐1, respectively. Amongst the phenylpyrazoles, only ethiprole can be considered less toxic in the group. Avermectins, pyrethroids and neonicotinoids were less toxic with LC50 values ranging from 1.29 to 2.57, 2.26 to 14.03 and 1.12 to 239.1 mg a.i.·L‐1, respectively. In contrast, insect growth regulators (IGRs) showed the least toxicity to the parasitoid with LC50 values ranging from 3383 (2406‐5499) to 5650 (4228‐8579) mg a.i.·L‐1. Conclusion Result of a risk quotient analysis indicated that neonicotinoids, avermectins, pyrethroids and IGRs were less hazardous, but phenylpyrazoles (except for ethiprole), organophosphates and carbamates were slightly to moderately or dangerously toxic to T. evanescens. Our results provided informative data for implementing biological and chemical control strategies in integrated pest management of lepidopterans.
  PubDate: 2013-04-30T13:14:11.153669-05:
  DOI: 10.1002/ps.3571
Activity of chlorantraniliprole and thiamethoxam seed treatments on life stages of the rice water weevil as affected by distribution of insecticides in rice plants
- Authors: Srinivas K Lanka; Michael J Stout, Julien M Beuzelin, James A Ottea
  Pages: n/a - n/a
  Abstract: Background Systemic insecticides, chlorantraniliprole (CAP) and thiamethoxam (TMX), applied to rice as seed treatments may affect multiple life stages of the rice water weevil, Lissorhoptrus oryzophilus. Effects of CAP and TMX on adult survival, egg‐laying and first and late instar survivals were determined by infesting plants treated as seeds with different rates of insecticides. The biological activity was related to insecticidal concentrations in leaves, shoots and roots. Results CAP did not affect adult survival but decreased egg numbers, and reduced survival of the first and late instars. The greatest reduction in weevil population occurred in late instars feeding on roots. In contrast, TMX reduced adult survival, egg and larval numbers. The high biological activity of CAP on root feeding stages was consistent with the accumulation of CAP in roots, whereas, in TMX‐treated plants, high activity on adults correlated with high concentrations of TMX in leaves and stems. Conclusions The differential activity of insecticides on adults suggests poor inherent potency of CAP as an adulticide and/or its limited systemicity in foliage. The distribution of insecticide in specific plant parts can be attributed to different physico‐chemical properties of CAP and TMX. The field implications of this research on management of L. oryzophilus are discussed.
  PubDate: 2013-04-30T13:13:49.182268-05:
  DOI: 10.1002/ps.3570
A four‐component synthetic attractant for Drosophila suzukii (Diptera: Drosophilidae) isolated from fermented bait headspace
- Authors: Dong H. Cha; Todd Adams, Christopher T. Werle, Blair J. Sampson, John J. Adamczyk, Helmuth Rogg, Peter J. Landolt
  Pages: n/a - n/a
  Abstract: Background A mixture of wine and vinegar is more attractive than wine or vinegar to spotted wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), and ethanol and acetic acid are considered key to that attractiveness. In addition to ethanol and acetic acid, thirteen other wine and vinegar volatiles are antennally active to D. suzukii and might be involved in food‐finding. Results Out of the 13 antennally active chemicals, acetoin, ethyl lactate and methionol increased fly response to the mixture of acetic acid and ethanol in field trapping experiments. A 5‐component blend of acetic acid, ethanol, acetoin, ethyl lactate and methionol was as attractive as the starting mixture of wine and vinegar in field tests conducted in the states of Oregon and Mississippi. Subtracting ethyl lactate from the 5‐component blend did not reduce the captures of flies in the trap. However, subtracting any other compound from the blend significantly reduced the numbers of flies captured. Conclusion These results indicate that acetic acid, ethanol, acetoin and methionol are key olfactory cues for D. suzukii when attracted to wine and vinegar, which may be food‐finding behavior leading flies to fermenting fruit in nature. We anticipate that this 4‐component blend can be used as a highly attractive chemical lure for detection and management of D. suzukii.
  PubDate: 2013-04-30T13:10:30.150339-05:
  DOI: 10.1002/ps.3568
Clearance of ingested neonicotinoid pesticide (imidacloprid) in honey bees (Apis mellifera) and bumble bees (Bombus terrestris)
- Authors: James E. Cresswell; François‐Xavier L. Robert, Hannah Florance, Nicholas Smirnoff
  Pages: n/a - n/a
  Abstract: Background Bees in agricultural landscapes are exposed to dietary pesticides such as imidacloprid when they feed from treated mass‐flowering crops. Concern about the consequent impact on bees makes it important to understand their resilience. In the laboratory, we therefore fed adult worker bees on dosed syrup (125 µg L‐1 imidacloprid, 98 µg kg‐1) either continuously or as a pulsed exposure and measured their behaviour (feeding and locomotory activity) and whole‐body residues. Results On dosed syrup, honey bees maintained much lower bodily levels of imidacloprid than bumble bees (< 0.2 ng vs. 2.4 ng imidacloprid per bee). Dietary imidacloprid did not affect the behaviour of honey bees but it reduced feeding and locomotory activity in bumble bees. After the pulsed exposure, bumble bees cleared bodily imidacloprid after 48 hours and recovered behaviourally. Conclusion We attribute the differential behavioural resilience of the two species to the observed differential in bodily residues. The ability of bumble bees to recover may be environmentally relevant in wild populations that face transitory exposures from the pulsed blooming of mass‐flowering crops.
  PubDate: 2013-04-30T13:05:35.005805-05:
  DOI: 10.1002/ps.3569
Environmental fungicides and triazole resistance in Aspergillus
- Authors: Paul Bowyer; David W. Denning
  Pages: n/a - n/a
  Abstract: Fungal diseases are problematic in both human health and agriculture. Treatment options are limited and resistance may emerge. The relatively recent recognition of triazole resistance in Aspergillus fumigatus has prompted questioning of the origin of resistance. While multiple mechanisms are described in clinical isolates from triazole‐treated patients, some de novo resistance is also recognized, especially attributable to TR34/L98H. Such strains probably arose in the environment and indeed multiple studies have now demonstrated TR34/L98H triazole resistance strains of A. fumigatus from soil. Docking and other in vitro studies are consistent with environmental resistance induction through exposure to certain triazole fungicides, notably difenoconazole, propiconazole, epoxiconazole, bromuconazole and tebuconazole. This article addresses the potential implications of this issue for both human health and food security..
  PubDate: 2013-04-24T12:28:31.765816-05:
  DOI: 10.1002/ps.3567
Effect of new and old pesticides on Orius armatus (Gross) ‐ an Australian predator of western flower thrips, Frankliniella occidentalis (Pergande)
- Authors: Sonya Broughton; Jessica Harrison, Touhidur Rahman
  Pages: n/a - n/a
  Abstract: Background Orius armatus (Gross) is an important predator of western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) in Australian greenhouse grown sweet pepper. The failure of O. armatus to establish in some greenhouses has been attributed to the use of newer, more non‐selective pesticides, some of which are regarded to be compatible with integrated pest management. The residual toxicity (via direct and indirect contact) of several older and newer chemistry pesticides were evaluated. In addition, the effect of several systemic insecticides through insecticide‐treated food‐chain uptake was tested. Results Older chemistry pesticides (methamidophos, dimethoate) were toxic to O. armatus, except pirimicarb which was non‐toxic. Newer chemistry pesticides differed in their suitability. Abamectin was toxic to adults and nymphs. Chlorantraniliprole, imidacloprid and spirotetramat were non‐toxic. Spinosad and spinetoram were moderately toxic to O. armatus. Spinosad also reduced fecundity by 20% compared to the untreated control. Pymetrozine was non‐toxic, but females exposed to treated beans produced 30% fewer eggs and 20% fewer nymphs hatched compared to the untreated control. Conclusions The selective pesticides do not necessarily facilitate the conservation of beneficials, and further assessment of the various developmental stages and other sub‐lethal effects of chlorantraniliprole, imidacloprid, pymetrozine, spinetoram, and spirotetramat is recommended.
  PubDate: 2013-04-24T10:36:32.645816-05:
  DOI: 10.1002/ps.3565
Metalized Polyethylene Mulch to Repel Asian Citrus Psyllid, Slow Spread of Huanglongbing and Improve Growth of New Citrus Plantings
- Authors: Scott D. Croxton; Philip A. Stansly
  Pages: n/a - n/a
  Abstract: Background Greening or huanglongbing (HLB) is a debilitating disease of citrus caused by Candidatus Liberibactor asiaticus and transmitted by the Asian citrus psyllid (ACP), Diaphorina citri. HLB now occurs worldwide in all major citrus growing regions except the Mediterranean and Australia. Management relies principally on insecticidal control of the ACP vector, but is insufficient, even for young trees which are most susceptible to the disease. We tested the ability of metalized polyethylene mulch to repel adult ACP as well as effects on incidence of HLB and early tree growth. Results Metalized mulch significantly reduced ACP populations and HLB incidence compared to whiteface mulch or bare ground. In addition, metalized mulch, together with the associated drip irrigation and fertigation system, increased soil moisture, reduced weed pressure, and increased tree growth rate. Conclusion Metalized mulch slows spread of ACP and therefore HLB pressure on young citrus trees. Metalized mulch can thereby augment current control measures for young trees based primarily on systemic insecticides. Additional costs could be compensated for by increased tree growth rate which would shorten time to crop profitability. These advantages make a compelling case for large scale trials using metallized mulch in young citrus plantings threatened by HLB.
  PubDate: 2013-04-24T10:35:49.237675-05:
  DOI: 10.1002/ps.3566
Detection and geographical distribution of the organophosphate resistance‐associated Δ3Q ace mutation in the olive fruit fly, Bactrocera oleae (Rossi)
- Authors: Evdoxia G Kakani; Efthymia Sagri, Michalis Omirou, Ioannis M Ioannides, Kostas D Mathiopoulos
  Pages: n/a - n/a
  Abstract: Background The olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae), is the most important pest of olives. Its control is based mostly on organophosphate (OP) insecticides, a practice that has led to resistance development. Organophosphate resistance in B. oleae has been associated with three mutations in the acetylcholinesterase (AChE). The current study presents new diagnostic tests for the detection of the ace mutations and aims at monitoring the frequency of the Δ3Q mutation, which appears associated with resistance at higher OP doses, in natural olive fly populations. Results An allele‐specific PCR, a PCR‐RFLP and a TaqMan test were developed for the Δ3Q mutation detection and a new duplex qPCR assay was designed for the G488S and I214V mutations. Moreover, the frequency of Δ3Q mutation was examined in 10 populations of eight countries around the Mediterranean basin. The highest frequencies (10%) were found in Greece and Italy, whereas a gradual decrease of Δ3Q frequency towards the Western Mediterranean was noted. Conclusion Robust tests for insecticide resistance mutations at their incipient levels are essential tools to monitor the increase and geographical spread of such mutations. Three different tests were developed for AChE‐Δ3Q that indicated its association with OP applications across the Mediterranean.
  PubDate: 2013-04-23T13:01:59.551763-05:
  DOI: 10.1002/ps.3564
Mechanisms of resistance to acetolactate synthase‐inhibiting herbicides in populations of Apera spica‐venti from the Czech Republic
- Authors: Kateřina Hamouzová; Pavlína Košnarová, Jaroslav Salava, Josef Soukup, Pavel Hamouz
  Pages: n/a - n/a
  Abstract: Background This study investigates the mechanisms of resistance to acetolactate synthase‐inhibiting herbicides in populations of Apera spica‐venti (L.) P.B. from the Czech Republic. Results The proportion of resistance due to mutant acetolactate synthase (ALS) alleles was estimated by genotyping individuals from each of three populations for the eight ALS mutations known to confer resistance. Four resistance‐conferring ALS mutations were identified: Pro‐197‐Ala, Pro‐197‐Thr, Trp‐574‐Leu and previously unreported Trp‐574‐Met substitution. Two populations (R1, R3) have amino acid substitution at positions Pro‐197 and Trp‐574. Individuals from the R3 population had two different resistance alleles. In the R2 population, only the resistant Trp‐574‐Met substitution was detected. Ten other single point mutations were identified, but these were not related to resistance. The cytochrome malathion decreased chlorsulfuron resistance in the resistant populations that were examined. Although malathion increased mortality, the GR50 values were too high to conclude that non‐target‐based mechanism was the main one for the resistance in A. spica‐venti populations tested in this study. Conclusions Individuals of A. spica‐venti populations tested in this study possess the target‐site ALS resistance mutation and an additional so far unknown resistance mechanism (s).
  PubDate: 2013-04-23T13:01:55.144831-05:
  DOI: 10.1002/ps.3563
Sensitivity of Phakopsora pachyrhizi towards Qo inhibitors and demethylation inhibitors, and corresponding resistance mechanisms†
- Authors: Helena K Schmitz; Carlos-Antonio Medeiros, Ian R Craig, Gerd Stammler
  Pages: n/a - n/a
  Abstract: Background Since the invasion of Phakopsora pachyrhizi (Syd. & P. Syd.) in Brazil, detrimental yield losses in soybeans [Glycine max (L.) Merr.] have occurred. Disease management is mainly based on fungicide treatment. The sensitivity of single P. pachyhrizi isolates towards different demethylation-inhibitors (DMIs) and quinone-outside-inhibitors (QoI) was surveyed and the corresponding resistance mechanisms were analyzed. Results The QoI-response remained stable, while a loss of sensitivity towards DMIs occurred. Molecular analyses of cytochrome b showed an intron after codon 143 which is reported to prevent the development of a G143A mutation. Analysis of cyp51 revealed that point mutations and overexpression are involved in the sensitivity reduction towards DMIs. As suggested by modelling studies, these three mutations as well as additional mutations F120L, I145F and I475T correlate to increased ED50-values towards all tested DMIs. Furthermore, a constitutive up-regulation of the cyp51-gene up to 10-fold was noticed in some of the DMI-adapted isolates, while all sensitive isolates responded as the wild type. Conclusion The G143A mutation is thought to result in significant as well as stable resistance factors towards QoIs, while other mutations play only a minor role. Since G143A development is prevented in P. pachyhrizi, a stable control of soybean rust with QoIs in future is rather likely. In contrast, a shifting in sensitivity towards DMIs has been observed, which is due to multiple independent mechanisms.
  PubDate: 2013-04-15T12:53:39.941467-05:
  DOI: 10.1002/ps.3562
Predictive 3D modelling of the interactions of pyrethroids with the voltage-gated sodium channels of ticks and mites
- Authors: Andrias O. O'Reilly; Martin S. Williamson, Joel González-Cabrera, Andreas Turberg, Linda M. Field, B. A. Wallace, T. G. Emyr Davies
  Pages: n/a - n/a
  Abstract: Background The pyrethroid insecticides are a very successful group of compounds that target invertebrate voltage-gated sodium channels and are widely used in the control of insects, ticks and mites. It is well established that some pyrethroids are good insecticides whereas others are more effective as acaricides. This species specificity is advantageous for controlling particular pest(s) in the presence of another non-target invertebrate, for example controlling the Varroa mite in honey bee colonies. Results We applied in-silico techniques to compare the voltage-gated sodium channels of insects versus ticks and mites and their interactions with a range of pyrethroids and DDT analogues. We identified a single amino acid difference within the pyrethroid binding pocket of ticks/mites that may have significant impact on the effectiveness of pyrethroids as acaricides. Other individual amino acid differences within the binding pocket in distinct tick and mite species may provide a basis for future acaricidal selectivity. Conclusions 3D modelling of the pyrethroid/DDT receptor site has led to a new hypothesis to explain the preferential binding of acaricidal pyrethroids to the sodium channels of ticks/mites. This is important for understanding pyrethroid selectivity and the potential effects of mutations that can give rise to resistance to pyrethroids in commercially-important pest species.
  PubDate: 2013-04-15T12:52:25.095269-05:
  DOI: 10.1002/ps.3561
Multi-generational effects of rice harboring Bph15 on brown planthopper, Nilaparvata lugens
- Authors: Jie Li; Keke Shang, Jia Liu, Tingru Jiang, Hongxia Hua
  Pages: n/a - n/a
  Abstract: Background The brown planthopper (BPH), Nilaparvata lugens, is one of the most devastating rice pests in Asia. Resistant cultivars are an effective way of managing BPH. Bph15 is a BPH resistance gene and has been introgressed into rice variety Minghui 63 (MH63). The multi-generational effects of rice line MH63::15 (harboring Bph15) on BPH were investigated and compared with its parental line MH63. Results U-test analysis indicated that, over seven generations, the developmental duration of BPH nymphs was significantly prolonged by MH63::15. The results of a two-way analysis indicated that, over seven generations, MH63::15 had significant negative effects on the hatchability, emergence rate, copulation rate, weight of adults and fecundity of BPH, but no significant effects on the survival rate of nymphs or female ratio of BPH. In addition, the development of ovary was significantly retarded by MH63::15, and the expression of oogenesis genes were either down-regulated (three genes) or up-regulated (one genes) by MH63::15 compared with MH63. Conclusions After being reared continuously on MH63::15 for seven generations, most of the life parameters of BPH were negatively affected by MH63::15, especially fecundity and ovary development. These results indicate that MH63::15 rice has potential for use in the control of BPH.
  PubDate: 2013-04-15T12:50:49.684185-05:
  DOI: 10.1002/ps.3560
Automated locomotor activity monitoring as a quality control assay for mass-reared tephritid flies
- Authors: Bernard C Dominiak; Benjamin G Fanson, Samuel R Collins, Phillip W Taylor
  Pages: n/a - n/a
  Abstract: Background The Sterile Insect Technique (SIT) requires vast numbers of consistently high quality insects to be produced over long periods. Quality control (QC) procedures are critical to effective SIT, both providing quality assurance and warning of operational deficiencies. We here present a potential new QC assay for mass rearing of Queensland fruit flies (Bactrocera tryoni Froggatt) for SIT; locomotor activity monitoring (LAM). , We investigated whether automated locomotor activity monitors that simply detect how often a fly passes an infrared sensor in a glass tube might provide similar insights but with much greater economy. Results Activity levels were generally lower for females than for males, and declined over 5 days in the monitor for both sexes. Female activity levels were not affected by irradiation, but males irradiated at 60 or 70 Gy had reduced activity levels compared with unirradiated controls. We also found some evidence that mild heat shock of pupae results in adults with reduced activity. Conclusion LAM offers a convenient, effective and economical assay to probe such changes.
  PubDate: 2013-04-15T12:50:36.513399-05:
  DOI: 10.1002/ps.3559
Multiple glutathione S-transferase genes: identification and expression in oriental fruit fly, Bactrocera dorsalis
- Authors: Fei Hu; Wei Dou, Jing-Jing Wang, Fu-Xian Jia, Jin-Jun Wang
  Pages: n/a - n/a
  Abstract: Background The oriental fruit fly, Bactrocera dorsalis (Hendel) is widely distributed in Asia-Pacific regions, where it is a serious pest of a wide range of tropical and subtropical fruit and vegetable crops. In this study, seventeen cDNA encoding glutathione S-transferases (GSTs) in B. dorsalis were sequenced and characterized. Results Phylogenetic analysis revealed that sixteen GSTs belonged to five different cytosolic classes, including four in delta, eight in epsilon, two in omega, one in theta, and one in zeta. The remaining GST (BdGSTu1) was unclassified. RT-qPCR assay showed that the relative expression levels of five GST genes were significantly higher in larval stages than in adulthood. Tissue-specific expression analysis found that BdGSTe3, BdGSTe9, and BdGSTd5 were expressed highly in the midgut, BdGSTe4, BdGSTe6, BdGSTd6,and BdGSTz2 were higher in the fat body, and six GSTs were higher in Malpighian tubules. RT-qPCR confirmed that the expressions of nine GST genes were increased by malathion exposure at various times and doses, while BdGSTe4, BdGSTe9, and BdGSTt1 were increased by β-cypermethrin exposure. Conclusion The increases in GST gene expression levels after malathion and β-cypermethrin exposure in B. dorsalis might elevate the ability of this species to detoxify other insecticides and xenobiotics.
  PubDate: 2013-04-15T12:50:33.349176-05:
  DOI: 10.1002/ps.3558
Susceptibility status of Culex quinquefasciatus (Diptera: Culicidae) populations to the chemical insecticide temephos in Pernambuco ‐ Brazil
- Authors: Liliane Barbosa Amorim; Elisama Helvecio, Cláudia Maria Fontes de Oliveira, Constância Flávia Junqueira Ayres
  Pages: n/a - n/a
  Abstract: Background Culex quinquefasciatus is the vector of many agents of human diseases, including Wuchereria bancrofti, the parasite that causes bancroftian filariasis, an endemic disease in Pernambuco State, Brazil. Although temephos is not currently used to control C. quinquefasciatus, the species might be under a selection process from incidental exposure to this compound. This study aimed to evaluate the susceptibility status of C. quinquefasciatus to temephos using bioassays and to investigate its putative resistance mechanisms through biochemical assays and screening the G119S mutation in the acetylcholinesterase gene, which is associated with organophosphate resistance, carried out by PCR and sequencing. Results The results showed that only mosquitoes from Santa Cruz do Capibaribe (SC) had an alteration in their susceptibility status (RR = 5.8 fold), while the other populations were all susceptible to the insecticide. Biochemical assays showed increased activity for all esterases in SC as well as evidence of acetylcholinesterase insensitivity. The G119S mutation was detected in this population with a frequency of 0.11, but it was not found in the remaining populations. Conclusion These data show that mechanisms of temephos resistance have been selected in natural C. quinquefasciatus populations from Pernambuco, which could undermine future control actions.
  PubDate: 2013-04-10T13:02:22.477547-05:
  DOI: 10.1002/ps.3502
Identification of a new PSII target site psbA mutation leading to D1 amino acid Leu218Val exchange in the Chenopodium album D1 protein and comparison to cross resistance profiles of known modifications at positions 251 and 264
- Authors: Heike Thiel; Mark Varrelmann
  Pages: n/a - n/a
  Abstract: Background Resistance of C. album to triazinones and triazines can be caused by two amino acid exchanges, serine‐264‐glycine (Ser264Gly) and alanine‐251‐valine (Ala251Val), in the chloroplast D1 protein. This paper describes the identification of a biotype with a leucine‐218‐valine (Leu218Val) switch found in German sugar beet fields with unsatisfactory weed control. A greenhouse experiment has been performed to compare the resistance profile of the newly identified biotype with biotypes that carry the Ser264Gly and Ala251Val mutations. Results Application rate‐response curves obtained from the greenhouse experiment showed that the Leu218Val exchange induced significant resistance against the triazinones but not against terbuthylazine. The level of resistance against the triazinones was higher in the Ser264Gly and Ala251Val biotypes compared with the Leu218Val biotype. All biotypes tested were more resistant to metribuzin than to metamitron. Following terbuthylazine treatment, Ser264Gly displayed a high level of resistance, Ala251Val showed moderate resistance. A PCR‐RFLP assay for Ser264Gly has been extended to include detection of Ala251Val and Leu218Val mutations. Conclusion The D1 Leu218Val substitution in C. album confers significant resistance to triazinones. This suggests that Leu218Val is involved in the binding of triazinones. First establishment of the resistance profiles of the three psbA mutations suggests that these mutations have been independently selected.
  PubDate: 2013-04-09T13:57:50.809785-05:
  DOI: 10.1002/ps.3556
Ant Control Efficacy of Pyrethroids and Fipronil on Outdoor Concrete Surfaces
- Authors: Weiying Jiang; Andrew Soeprono, Michael K. Rust, Jay Gan
  Pages: n/a - n/a
  Abstract: Urban and residential concrete surfaces are often treated with pesticides to control ants. Runoff from irrigation/rainfall can remove pesticides from concrete and contaminate urban waterways. Recent regulations and mitigations in regions such as California aim to reduce insecticide runoff (e.g., pyrethroids), but often proposed without adequate consideration of their impact on ant control efficacy. We carried out an outdoor study with a side‐by‐side comparison between pesticide runoff potential and residual ant toxicity after exposing treated concrete to summer conditions and simulated precipitations. Treatments of bifenthrin, permethrin or fipronil all showed fast ant knockdown initially, and over 50% of ants were killed within 16‐h after 1‐min contact with the treated surfaces. Shorter ant median lethal time (LT50) was observed on concrete treated with over‐the‐counter (OTC) granule/dust formulations than OTC liquid or professional formulations. However, the treated surfaces rapidly lost ant control efficacy after outdoor exposure and repeated precipitations. Except for OTC solid permethrin treatment, the ant toxicity disappeared after 20‐d for all other formulation treatments. In contrast, pesticides were detected in runoff water from simulated precipitations even 89‐d after the treatment, with levels above 0.5 µg/L for bifenthrin, 30 µg/L for permethrin and 0.15 µg/L for fipronil. Pyrethroid runoff from OTC solid formulations were >10 times higher than the other two formulations. The results suggested viable options for runoff mitigation include decreasing use on concrete such as using crack/spot treatments instead of broadcast applications, limiting pesticide use on hardscapes away from water contact, and avoiding using dust/granule formulations on hardscapes.
  PubDate: 2013-04-09T13:56:36.17335-05:0
  DOI: 10.1002/ps.3555
Behavioral and EAG responses of the stable fly (Stomoxys calcitrans L.) to plant essential oils and their mixtures with attractants
- Authors: Hieu Trung Tran; Je‐Won Jung, Soon‐Il Kim, Young‐Joon Ahn, Hyung Wook Kwon
  Pages: n/a - n/a
  Abstract: Background Insect olfactory organs possess many olfactory receptor neurons, which detect many different sets of odorants in nature. In order to feed on blood meals, stable flies locate host animals and humans using chemical cues such as 1‐octen‐3‐ol and butyric acid. In the present study, behavioral and EAG response patterns to repellent volatiles from essential oils (EOs) of Zanthoxylum piperitum and Z. armatum in combination with the attractants were investigated. Results Components of the EOs such as cuminaldehyde, citronellal, neral, linalool, linalool oxide, terpinen‐4‐ol, 1,8‐cineole, and piperitone induced remarkable repellent behaviors in the stable fly. EAG responses in the fly antenna to these chemicals showed a dose‐dependent manner. The patterns of behavioral and EAG responses were significantly altered depending on the ratios of 1‐octen‐3‐ol or butyric acid to the EOs or compounds in the air mixtures. Conclusion The present study demonstrated that the Zanthoxylum EOs decreased the levels of response of flight behaviors of the stable fly towards host volatile compounds. The combinations of odorant mixtures of the attractants with the EOs and their components affect the representation of behavioral and EAG responses of the flies. The summation and integration patterns of olfactory responses measured by EAG indicated that the peripheral olfactory networks in antennae could process the odorant complexity of different odorant mixtures between attractants and repellents.
  PubDate: 2013-04-05T16:35:34.845902-05:
  DOI: 10.1002/ps.3547
Integrated Biological and Chemical Control of Rice Sheath Blight By Bacillus subtilis NJ‐18 and Jinggangmycin
- Authors: Di Peng; Shandong Li, Jianxin Wang, Changjun Chen, Mingguo Zhou
  Pages: n/a - n/a
  Abstract: Background Sheath blight caused by Rhizoctonia solani Kühn is a major disease of rice that greatly reduces yield and grain quality and jinggangmycin is the most widely used fungicide to control this disease in China. Bacillus subtilis NJ‐18 has broad antimicrobial activity to many phytopathogenic bacteria and fungi; it is especially effective against Rhizoctonia solani. Laboratory, greenhouse, and field tests were conducted to determine the effect of combining the biological control agent Bacillus subtilis NJ‐18 with the fungicide jinggangmycin for control of rice sheath blight. Results Growth of NJ‐18 in vitro was not affected by jinggangmycin. In a greenhouse experiment, disease control was greater with a mixture of NJ‐18 and jinggangmycin than with either alone; a mixture of NJ‐18 at 108 cfu ml‐1 and jinggangmycin at 50 or 100 mg L‐1 reduced lesion length by 35% and 20%, respectively, and the combinations showed a synergistic action. In three field trials, disease control was significantly greater with a mixture of NJ‐18 at 108 cfu ml‐1 and jinggangmycin at 75 or 150 g a.i. ha‐1 than with either component alone. Conclusion The results of the study indicate that, when Bacillus subtilis NJ‐18 strain was combined with jinggangmycin, there was an increased suppression of rice sheath blight, and thus could provide an alternative disease control option.
  PubDate: 2013-04-05T15:11:22.722111-05:
  DOI: 10.1002/ps.3551
A functional study of two dsRNA binding protein genes in Laodelphax striatellus
- Authors: LU Ding‐hao; WU Min, PU Jian, ZHANG Qian, HAN Zhao‐jun
  Pages: n/a - n/a
  Abstract: Background One of the key limiting factors for using RNA interference technology to develop new pest control practices is the toxicological effectiveness. In order to explore potential methods to improve the efficiency of RNAi in insects, we cloned two dsRNA binding proteins from Laodelphax striatellus and investigated their functions. Results In this study, the genes homologous to the dsRNA binding proteins TRBP and STAU in L. striatellus were first cloned and designated as LsTRBP and LsSTAU. Using the chitinase gene Chi, which has been confirmed to have lethal effects when knocked down by RNAi, as a reporter, the functions of these two dsRNA binding proteins were then investigated by using feeding. The results showed that feeding with dsChi alone caused significant lethal effects, with a mortality fourfold higher than that of the control, whereas feeding with dsTRBP or dsSTAU alone did not yield any significant lethal effects. When dsChi was fed in the mixture 1:1 with dsSTAU, it also resulted in high mortality, which was a little lower than feeding with dsChi alone, but not statistically significant. However, when fed in the 1:1 mixture with dsTRBP, the lethal effect of dsChi was completely eliminated. Further analysis of gene expression found that single dsRNA depressed only its own target gene. When treated in 1:1 mixture, dsSTAU or dsChi did not change significantly the depression of the other dsRNA, but dsTRAB counteracted almost all the effect of dsChi. Conclusion These results indicate that the loss of LsTRBP can significantly inhibit dsChi‐mediated genetic interference. These findings not only suggest that the LsTRBP gene in L. striatellus plays an import role in regulating RNAi but also imply that the metabolic regulation of dsRNAs with respect to genetic interference in L. striatellus is similar to that in higher animal species.
  PubDate: 2013-04-05T14:06:31.639451-05:
  DOI: 10.1002/ps.3553
Herbicidal activity of formulated sorgoleone, a natural product of sorghum root exudate
- Authors: Md Romij Uddin; Sang Un Park, Franck E. Dayan, Jong Yeong Pyon
  Pages: n/a - n/a
  Abstract: Background The allelochemical, sorgoleone, a major component of the hydrophobic root exudates of Sorghum bicolor, was formulated as a wettable powder [4.6 WP] and evaluated as a natural herbicide on several weed and crop species under different growth conditions. Results Formulated sorgoleone [4.6 WP] suppressed germination and shoot growth of weeds, with broadleaf species showing greater susceptibility than grass weed species. Germination and growth of broadleaf weed species were completely suppressed (100%) at 0.2 g ai/L sorgoleone in a growth chamber study. Post‐emergence applications of wettable formulation of sorgoleone [4.6 WP] inhibited 20‐25% higher growth of weeds than pre‐emergence applications under greenhouse conditions. Broadleaf weeds were more susceptible than grass species to both methods of application. In all studies, growth was suppressed in more than 90% of the broadleaf weeds and two species, in particular, Rumex japonicus and Plantago asiatica, were completely suppressed at 0.4 kg ai/ha sorgoleone. The crop species on the other hand were much more tolerant to sorgoleone, with at most 30% inhibition at the highest rate of 0.4 kg ai/ha sorgoleone. Conclusion The results of this study reveal that sorgoleone, after formulation as a WP, is more effective in inhibiting weed growth, and crop species are tolerant to it. The strong weed suppressive ability of formulated sorgoleone therefore offers interesting possibilities as an effective natural environment‐friendly approach for weed management.
  PubDate: 2013-04-05T14:04:42.312735-05:
  DOI: 10.1002/ps.3550
Simultaneous quantification of alleles E198A and H6Y in beta‐tubulin gene conferring benzimidazole resistance in Monilinia fructicola using a duplex real‐time (TaqMan) PCR
- Authors: Jinyan Fan; Yong Luo, Themis J Michailides, Liyun Guo
  Pages: n/a - n/a
  Abstract: Background The benzimidazole fungicide thiophanate‐methyl is commonly used for control of brown rot of stone fruits. Low and high levels of resistance to this fungicide have been found in field isolates of the causal pathogen Monilinia fructicola. Results The minor groove binding (MGB) TaqMan‐probes specific for alleles E198A and H6Y conferring the high and low levels of resistance in the β‐tubulin gene of M. fructicola were designed. A duplex real‐time PCR assay based on these probes was developed for simultaneous quantification of both mutations in a pathogen population. The specificity tests for the primers and probes were conducted using different fungal species of stone and pome fruit pathogens. Similar results were obtained between the duplex real‐time (TaqMan) PCR assay and the conventional method to quantify the frequencies of alleles E198A and H6Y of eight samples from different peach orchards. Conclusion The MGB TaqMan probe based duplex real‐time PCR provides a useful tool for simultaneous quantification of both alleles E198A and H6Y conferring high and low resistance, and has a potential in monitoring the benzimidazole‐resistance in M. fructicola populations in stone and pome fruit orchards.
  PubDate: 2013-04-05T14:03:41.646401-05:
  DOI: 10.1002/ps.3549
Enhanced herbicide metabolism induced by 2, 4‐D in herbicide susceptible Lolium rigidum provides protection against diclofop‐methyl
- Authors: Heping Han; Qin Yu, Gregory R Cawthray, Stephen B Powles
  Pages: n/a - n/a
  Abstract: Background The auxinic herbicide 2, 4‐D amine is known, in vitro, as a cytochrome P450 inducer. The current study uses 2, 4‐D pre‐treatment, at the whole plant level, to study mechanism(s) of non‐target site based herbicide resistance to the ACCase‐inhibiting herbicide diclofop‐methyl in Lolium rigidum. Results The 2, 4‐D pre‐treatment caused up to 10‐fold shift in LD50 and GR50 in dose response to subsequently applied diclofop‐methyl in an herbicide susceptible L. rigidum population. Foliar uptake and translocation of 14C‐diclofop‐methyl did not differ in 2, 4‐D pre‐treated versus untreated plants. HPLC analysis revealed that de‐esterification of diclofop‐methyl to toxic diclofop acid was similar, but further metabolism of diclofop acid to non‐toxic metabolites was significantly (1.8 fold) faster in 2, 4‐D pre‐treated than untreated plants. HPLC profile of major polar metabolites was similar when L. rigidum and diclofop‐methyl tolerant wheat were compared, but wheat metabolised diclofop acid 3‐fold faster than L. rigidum. In addition, 2, 4‐D pre‐treatment also induced cross‐protection against the ALS‐inhibiting herbicide chlorsulfuron, and the known P450 inhibitor malathion can reverse this effect. Conclusions Protection against diclofop‐methyl provided by 2, 4‐D pre‐treatment in susceptible L. rigidum is associated with higher rates of herbicide metabolism, mirroring that identified in field‐evolved, non‐target site‐based diclofop‐methyl resistant populations. 2, 4‐D may induce higher level expression of herbicide‐metabolising genes hence providing protection, and therefore, this 2, 4‐D induction system can be used, in combination with other genomic approaches, to assist isolating cytochrome P450 and other genes that are involved in herbicide metabolism and endow herbicide resistance in L. rigidum.
  PubDate: 2013-04-05T14:01:30.790921-05:
  DOI: 10.1002/ps.3552
Nematotoxicity of drupacine and a Cephalotaxus alkaloid preparation against the plant‐parasitic nematodes Meloidogyne incognita and Bursaphelenchus xylophilus
- Authors: Wen Yanhua; Susan L F Meyer, Edward P Masler, Zhang Fengxian, Liao Jinling, Wei Xiaoyi, David J Chitwood
  Pages: n/a - n/a
  Abstract: Background Species of Cephalotaxus (the plum yews) produce nematotoxic compounds of unknown identity. Consequently, bioassay‐guided fractionation was employed to identify the compound(s) in Cephalotaxus fortunei twigs and leaves with activity against plant‐parasitic nematodes. Results A crude alkaloid extract, particularly drupacine, was responsible for much of the nematotoxicity. The ED50 of drupacine for Bursaphelenchus xylophilus was 27.1μg mL–1, and for Meloidogyne incognita it was 76.3 µg mL–1. Immersion of M. incognita eggs in 1.0 mg mL–1 crude alkaloid extract (the highest tested concentration) reduced hatch 36%; immersion of second‐stage juveniles (J2) resulted in 72% to 98% immobility. Crude alkaloid extract and drupacine suppressed protease activity in extracts of the microbivorous nematode Panagrellus redivivus 50% and 80%, respectively. Application of 0.02 to 0.5 mg mL–1 crude alkaloid extract to soil with M. incognita inoculum did not significantly reduce pepper plant shoot length or weight, compared with nematode‐inoculated, water‐treated controls, but the number of eggs and J2 per root system respectively decreased by 69% and 73% at 0.5 mg mL–1. Conclusion Drupacine and a crude alkaloid extract suppress nematode hatch, activity of mixed life stages, and population numbers on plant roots. This is the first demonstration of nematotoxicity of crude Cephalotaxus alkaloids and drupacine.
  PubDate: 2013-04-05T14:01:21.152572-05:
  DOI: 10.1002/ps.3548
An improved bioassay facilitates the screening of repellents against cat flea Ctenocephalides felis (Siphonaptera: Pulicidae)
- Authors: Li‐Chong Su; Chin‐Gi Huang, Shang‐Tzen Chang, Shu‐Hui Yang, Shan‐Hui Hsu, Wen‐Jer Wu, Rong‐Nan Huang
  Pages: n/a - n/a
  Abstract: Background Repellents are a common method for preventing flea bites, making an effective system for flea repellent screening advantageous. We describe an improved technique to facilitate repellent activity screening of numerous plant‐based Ctenocephalides felis (cat flea) repellents. Results Two long strips of filter paper were impregnated with test compounds (dissolved in ethanol) and ethanol only, respectively. After drying, the 2 filter papers were glued together along the long side and inserted into a glass tube containing non‐fed cat fleas. The distribution of cat fleas in each half of the filter paper was recorded after 30 min to calculate repellency. Results showed that the essential oil of Cinnamomum osmophloeum (from leaf), Taiwania cryptomerioides (from heartwood) and Plectranthus amboinicus (from leaf) exhibits repellent activity against cat fleas in a dose dependent manner. Moreover, the repellent activities against cat fleas of 2% trans‐cinnamaldehyde (the main constituent of Ci. osmophloeum essential oil) and 0.5% thymol (the main constituent of P. amboinicus essential oil) are 97.6% and 90.6%, and can persist for up to 4 and 8 h, respectively. These results are comparable to those of 15% DEET. Conclusion The proposed screening technique can facilitate the pre‐screening of numerous flea repellents for further evaluation on animal or human subjects.
  PubDate: 2013-04-05T14:01:16.856591-05:
  DOI: 10.1002/ps.3554
Estimating economic thresholds for site‐specific weed control using manual weed counts and sensor technology: An example based on three winter wheat trials
- Authors: Martina Keller; Christoph Gutjahr, Jens Möhring, Martin Weis, Markus Sökefeld, Roland Gerhards
  Pages: n/a - n/a
  Abstract: Background The Precision Experimental Design (PED) uses the natural heterogeneity of agricultural fields and combines sensor technology with linear mixed models to estimate the effect of weeds, soil properties and herbicide on yield. These estimates can be used to derive economic thresholds. Three field trials are presented using the PED in winter wheat. Weed densities were determined by manual sampling and bi‐spectral cameras, yield and soil properties were mapped. Results Galium aparine, other broad‐leaved weeds and Alopecurus myosuroides reduced yield by 17.5, 1.2 and 12.4 kg ha‐1 plant‐1 m2 kg in one trial. The determined thresholds for site‐specific weed control with independently applied herbicides were 4, 48 and 12 plants m‐2, respectively. Spring drought reduced yield effects of weeds considerably in one trial, since water became yield limiting. A negative herbicide effect on the crop was negligible, except in one trial, in which the herbicide mixture tended to reduce yield by 0.6 t ha‐1. Bi‐spectral cameras for weed counting were of limited use and still need improvement. Nevertheless, large weed patches were correctly identified. Conclusion The current paper presents a new approach to conduct field trials and derive decision rules for weed control in farmers’ fields.
  PubDate: 2013-04-02T10:10:14.293574-05:
  DOI: 10.1002/ps.3545
Fitness of twospotted spider mites is more affected by constitutive than induced resistance traits in cotton (Gossypium spp.)
- Authors: Junji Miyazaki; Lewis J. Wilson, Warwick N. Stiller
  Pages: n/a - n/a
  Abstract: Background Life history parameters are useful tools for comparing the fitness of pests on different host plants. This study compared life history parameters of twospotted spider mites (Tetranychus urticae Koch) on two resistant cotton Gossypium genotypes (BM13H and Sipima 280) and one susceptible genotype (Sicot 71). The effects of both constitutive and induced defences were assessed. Results Mites reared on the resistant genotypes had longer immature development times, lower immature survival and reduced adult fecundity. Mites reared on BM13H that had been induced by prior exposure to mites had a small additional decrease in adult fecundity. The contribution to mite resistance of constitutive resistance mechanisms was much greater than induced responses. The effect of morphological constitutive defences was minor, implicating biochemical defences as the major mite‐resistance mechanism. Sensitivity analysis and a population development study using life history parameters of mites showed that a lower immature survival rate on resistant genotypes had the greatest effect on mite fitness and population development. Conclusion Use of life history parameters provided valuable insight into the mite‐resistance mechanisms of these Gossypium genotypes. Further, the results largely explained mite population development on these genotypes in the field.
  PubDate: 2013-04-02T10:09:54.054584-05:
  DOI: 10.1002/ps.3546
Development of DNA microarray for the species identification of quarantine aphids
- Authors: Won Sun Lee; Hwalran Choi, JinSeok Kang, Ji‐Hoon Kim, Si Hyeock Lee, Seunghwan Lee, Seung Yong Hwang
  Pages: n/a - n/a
  Abstract: Backgroud Aphid pests are being brought into the country as crop trading has increased. Aphids exist on growth areas of plants; thus, plant growth is seriously affected by aphid pests. However, aphids are very small and have several sexual morphs and life stages, so it is difficult to identify species based on morphological features. We approached this problem using DNA microarray technology. Results DNA targets of the cytochrome c oxidase subunit I gene were generated with a fluorescent dye‐labeled primer and were hybridized onto a DNA microarray consisting of specific probes. After analyzing signal intensity of the specific probes, the unique patterns from the DNA microarray consisting of 47 species‐specific probes were obtained to identify23 aphid species. To confirm the accuracy of the developed DNA microarray, 10 individual blind samples were used in blind trials, and the identifications were completely consistent with the sequencing data of all individual blind samples. Conclusion We developed a microarray to distinguish aphid species. DNA microarray technology provides a rapid, easy, cost‐effective, and accurate method to identify aphid species for pest control management.
  PubDate: 2013-04-01T11:06:45.509591-05:
  DOI: 10.1002/ps.3520
Two pear varieties evaluated for resistance to pear psylla (Cacopsylla bidens (Sulc)) in Israel
- Authors: Liora Shaltiel‐Harpaz; Doron Holland, Victoria Soroker, Rika Kedoshim, Roy Hason, Tamar Sokalsky, Kamel Hatib, Irit Bar‐Ya'akov
  Pages: n/a - n/a
  Abstract: Background The pear psylla, Cacopsylla bidens (Sulc), is one of the most damaging pests of commercial pear orchards in Israel. Psylla control is a major obstacle to efficient integrated pest management, necessitating research on cultivars with natural resistance to pear psylla. Recently, two pear varieties (P.760‐261 and P.701‐202) from the local Newe Ya'ar fruit tree live collection (Israeli gene bank) were identified as having apparent resistance to pear psylla. Our goal was to evaluate the resistance of these two varieties relative to the commercial cultivar Spadona Estiva, and to identify whether the resistance mechanisms in the former interfere with insect colonization of the plant (antixenosis) or inhibit insect growth, development, reproduction and survival (antibiosis). Results Settlement and development of C. bidens was evaluated under natural conditions (pear orchard), semi‐natural conditions (potted plants), and on detached branches and leaves (laboratory). Our results indicate that the variety P.760‐261 is 10 times more resistant than Spadona while P.701‐202 is 5 times more resistant. Conclusions The resistance mechanism in both varieties appears to be antibiosis affecting nymph survival. These resistant varieties may be used as rootstock. Experiments demonstrating that these rootstocks provide the scion with resistance to pear psylla are currently being conducted at our laboratories.
  PubDate: 2013-03-30T11:39:17.065467-05:
  DOI: 10.1002/ps.3543
Effects of termiticide exposure on mutual interactions between the treated and untreated workers of the Asian subterranean termite Coptotermes gestroi
- Authors: Kok‐Boon Neoh; Ching‐Chen Lee, Chow‐Yang Lee
  Pages: n/a - n/a
  Abstract: Background The mutual interactions include reciprocal food sharing and grooming between chlorantraniliprole‐ and fipronil‐treated, and untreated Asian subterranean termites, Coptotermes gestroi (Wasmann) was examined using rubidium (Rb) as a tracer. Two questions were addressed in this study: (1) After insecticide treatment, does the mutual interaction between termiticide‐treated termites and untreated nestmates increase? (2) Does the nutritional status of both termiticide‐treated termites and untreated nestmates affect the mutual interaction? Results The comparative data suggested that chlorantraniliprole‐treated termites were more regularly attended by untreated termites than the fipronil‐treated termites. Mutual interaction between the chlorantraniliprole‐treated termites and untreated termites was not affected by their nutritional status. A high level of Rb was present in the reciprocal exchange from fipronil‐treated termites to starved untreated termites, indicating that intoxication induced alimentary or anal fluids served as a food source for starved termites. Conclusion The results of the present study indicated that termites exposed to chlorantraniliprole were more likely to cease feeding and then undergo starvation. Thus, the treated termites were subject to intensive reciprocal food exchange and frequent attention from untreated nestmates. In the fipronil treatment, starvation status facilitated the reciprocal food exchange rate from treated termites to starved untreated termites.
  PubDate: 2013-03-30T11:38:30.864291-05:
  DOI: 10.1002/ps.3544
Atrazine degradation in soil: effects of adjuvants and a comparison of three mathematical models
- Authors: Maria K Swarcewicz; Andrzej Gregorczyk
  Pages: n/a - n/a
  Abstract: Background There are few reports on the effects of spray adjuvants on pesticide persistence. The role of three adjuvants used with atrazine on the herbicide's degradation in soil was examined. Three mathematical models were used to describe pesticide disappearance from soil: pseudo‐first‐order kinetics, the non‐linear Gustafson–Holden model and the biexponential function. Results A mixture of atrazine with Atpolan 80 EC significantly inhibited herbicide soil degradation (DT50 = 78 days), while Adpros 85 SL and Break‐Thru S 240 (DT50 = 25 and 24 days respectively) had little effect (DT50 = 22 days, atrazine alone). These results suggest that adjuvant can be a factor in field persistence. DT50 values obtained using the Gustafson–Holden and biexponential models were similar. Only the biexponential model requires an iterative method. Conclusion A significant effect of one adjuvant on atrazine persistence in soil was observed. The biexponential model best described the disappearance of atrazine in the soil, as indicated by the values of R2 and RMS and the relative concentration of the herbicide in the soil.
  PubDate: 2013-03-26T07:31:07.716543-05:
  DOI: 10.1002/ps.3510
Methiozolin (5‐(2,6‐difluorobenzyl)oxymethyl‐5‐methyl‐3‐3(3‐methylthiophen‐2‐yl)‐1,2‐isoxazoline), a New Annual Bluegrass (Poa annua L.) Herbicide for Turfgrasses
- Authors: Suk‐Jin Koo; Ki‐Hwan Hwang, Man‐Seok Jeon, Sung‐Hun Kim, Jongsoo Lim, Dong‐Guk Lee, Nam‐Gyu Cho
  Pages: n/a - n/a
  Abstract: Background Selective control of annual bluegrass (Poa annual L.) has been difficult in turfgrasses. Potential of methiozolin in this area was investigated. Results Methiozolin was safe on established zoysiagrass (Zoysia japonica Steud.), creeping bentgrass (Agrostis palustris Huds.), Kentucky bluegrass (Poa pratensis L.), and perennial ryegrass (Lolium perenne L.) at 1000 g ha‐1, and controlled annual bluegrass with GR50 of 23, 52, 104, and 218 g ha‐1 at PRE, 2‐, 4‐, and 8‐leaf stage, respectively, in the greenhouse. When applied at early flowering, methiozolin suppressed >80% of annual bluegrass seed heads at 2000 g ha‐1. [14C]‐Methiozolin was readily absorbed by both leaves and roots, but translocation was mainly acropetal. No herbicidal activity resulted from application to the leaf only; however, application to the soil surface only showed equivalent herbicidal activity to that of broadcast application to the leaf and soil. Methiozolin at 500 to 1000 g ha‐1 provided 80 to 100% control of annual bluegrass when applied in the fall with acceptable and temporary injury to creeping bentgrass, and about 60% control when applied in the spring with no bentgrass injury in the field. Conclusion Methiozolin is an excellent candidate for annual bluegrass management in turfgrasses.
  PubDate: 2013-03-23T11:12:52.9547-05:00
  DOI: 10.1002/ps.3541
Transport properties of the Mung bean (Vigna radiata) non‐aerial hypocotyl membrane: Permselectivity to hydrophilic compounds
- Authors: John Aponte; Peter Baur
  Pages: n/a - n/a
  Abstract: Background Aerial plant surfaces are covered by a lipophilic cuticular membrane (CM) that restricts the transport of water and small solutes. Non‐aerial tissues do not exhibit such a barrier. Recent data have shown that large relative to CM hydrophilic agrochemicals were able to pass at high rates through the non‐aerial coleoptile. Results A moderately large hydrophilic solute like PEG 1000 with a mean molar volume of 782 cm3 mol‐1 was rejected by the non‐aerial hypocotyl. Uptake of smaller solutes like urea (46.5 cm3 mol‐1) was fast and with 99% after one day. Cut‐off size estimations suggest a pore size diameter below 1.5 nm. Conclusion Aerial and non‐aerial CM differ largely in their absolute barrier properties. This difference is related to the absence of embedded cuticular waxes in the non‐aerial hypocotyl membrane, which make the CM physically dense and cause low solubility of hydrophilic solutes. The free volume for diffusion at the interface of the non‐aerial hypocotyl cuticle to the environment is much larger resulting in higher penetration rates. It is suggested that diffusion through the non‐aerial hypocotyl does not proceed in a real channel system with continuous aqueous phase but is more like transport through a filter with restricted diffusion in the pore openings.
  PubDate: 2013-03-22T12:35:35.484401-05:
  DOI: 10.1002/ps.3540
How many genetic options for evolving insecticide resistance in heliothine and spodopteran pests?
- Authors: John G Oakeshott; Claire A Farnsworth, Peter D East, Colin Scott, Yangchun Han, Yidong Wu, Robyn J Russell
  Pages: n/a - n/a
  Abstract: The widely accepted paradigm for the development of insecticide resistance in field populations of insects is of selection for one or a very few genes of major effect. Limited genetic mapping data for organophosphate and pyrethroid resistance in heliothine and spodopteran pests generally agree with this paradigm. However other biochemical and transcriptomic data suggest a more complex set of changes in multiple P450 and esterase gene/enzyme systems in resistant strains of these species. We discuss possible explanations for this paradox, including the likely embedding of these genes in regulatory cascades and emerging evidence for their arrangement in large clusters of closely related genes. We conclude that there could indeed be an unusually large number of genetic options for evolving resistance in these species.
  PubDate: 2013-03-22T12:35:33.304292-05:
  DOI: 10.1002/ps.3542
Cloning and characterization of NADPH‐dependent cytochrome P450 reductase gene in the cotton bollworm, Helicoverpa armigera
- Authors: Chunqing Zhao; Tao Tang, Xiaoyun Feng, Lihong Qiu
  Pages: n/a - n/a
  Abstract: Background Previous studies in our laboratory showed that cytochrome P450 CYP6B7 plays a critical role in a Handan fenvalerate resistant strain (HDFR) of Helicoverpa armigera. As an important component of P450 enzyme systems, cytochrome P450 reductase (CPR) plays an essential role in transferring electrons from NADPH to P450‐substrate complex. However, little information about CPR in H. armigera (HaCPR) has been reported. Results A full‐length cDNA (3525 bp) of HaCPR was cloned. The open reading frame (ORF) of HaCPR gene encoded 687 amino acids and shared 27.87% ~ 95.21% identities with other known CPRs. Bioinformatic analysis showed that HaCPR is a transmembrane protein with Mw of 77.4 kDa and contains conserved features. The results of real‐time quantitative polymerase chain reaction (RT‐qPCR) showed that the expression level of HaCPR mRNA was 1.84‐fold higher in midgut of 5th instars of Handan susceptible (HDS) strain than that in pupae, and the level in the midgut of HDFR strain was 2.02‐fold higher than that of the HDS strain. The levels of HaCPR mRNA were induced by phenobarbital (PB) at concentrations of 2 and 4 mg/g, which enhanced 5.20‐ and 17.45‐fold respectively, compared to that of the control after 48 h of PB treatment. Conclusions The results indicate that HaCPR is important for development of H. armigera and may play an essential role in the P450‐mediated insecticide resistance of H. armigera to fenvalerate.
  PubDate: 2013-03-19T13:18:57.796845-05:
  DOI: 10.1002/ps.3538
Lethal and sublethal effects of thymol on honeybee (Apis mellifera) larvae reared in vitro
- Authors: Gael Charpentier; Cyril Vidau, Jean‐Baptiste Ferdy, Jeremy Tabart, Angelique Vetillard
  Pages: n/a - n/a
  Abstract: Background Thymol offers an attractive alternative to synthetic chemicals to keep Varroa under control. However, thymol accumulates in bee products and is suspected of having adverse effects on colonies and especially on larvae. In this study, we investigated the effects of acute and chronic exposure to thymol on larvae reared in vitro with contaminated food and compared results to the theoretical larval exposure based on the amount of pollen and honey consumed by larvae during their development. Results The laboratory assays reveal that 1) the 48h‐LD50 of thymol introduced into larval food is 0.044 mg larva ‐1 2) the six days‐LC50 is 700 mg kg ‐1 of food. A significant decrease of larval survival and mass occurred from 500 mg of thymol per kg of food (P < 0.0001) 3) finally, the vitellogenin expression, which reached a maximum at the fifth instar larvae, is delayed for individuals exposed from 50 mg of thymol per kg of food (P < 0.0006). That is ten time higher than the theoretical level of exposure. Conclusion Based on the level of thymol residue found in honey and pollen, these results suggest that the contamination of food by thymol represents no notable risk for the early‐developing larvae.
  PubDate: 2013-03-19T13:08:55.313697-05:
  DOI: 10.1002/ps.3539
A comparative study of competitiveness between different genotypes of weedy rice (Oryza sativa) and cultivated rice
- Authors: Lei Dai; Weimin Dai, Xiaoling Song, Baorong Lu, Sheng Qiang
  Pages: n/a - n/a
  Abstract: Background Competition from weedy rice can cause serious yield losses to cultivated rice. However, key traits that facilitate competitiveness are still not well understood. To explore the mechanisms behind the strong growth and competitive ability, replacement series experiments were established with six genotypes of weedy rice from different regions and one cultivated rice cultivar. Results (1) Weedy rice from southern China had the greatest impact on growth and yield of cultivated rice throughout the entire growing season. Weedy rice from the northeast was very competitive during the early vegetative stage while the competitive effects of eastern weedy rice were more detrimental at later crop‐growth stages; (2) as the proportion of weedy rice increased, plant height, tillers, aboveground biomass, and yield of cultivated rice significantly declined; the crop always being at disadvantage regardless of proportion; (3) weedy biotypes with greater diversity as estimated by their Shannon indexes were more detrimental to the growth and yield of cultivated rice. Conclusion Geographic origin (latitude) of weedy rice biotype, its mixture proportion under competition with the crop and its genetic diversity are determinant factors of the outcome of competition and the associated decline in the rice crop yield.
  PubDate: 2013-03-19T08:26:55.344474-05:
  DOI: 10.1002/ps.3534
Evaluation of Sunlight‐Exposed Pyrethroid‐Treated Netting for Control of Face Fly and House Fly (Diptera: Muscidae)
- Authors: George W. Peck; Holly J. Ferguson, Jane T. LePage, Vincent R. Hebert, Sally D. O'Neal, Douglas B. Walsh
  Pages: n/a - n/a
  Abstract: Background Face flies, Musca autumnalis De Geer (Diptera: Muscidae), and house flies, Musca domestica L. (Diptera: Muscidae), have a significant impact on livestock and dairy production throughout North America. Pyrethroid insecticide efficacy can be affected by exposure to direct sunlight and the rate of photodegradation is substrate and formulation dependent. Insecticide‐treated netting (ITN) is finding new applications in crop and livestock production systems. Here, we provide a baseline study using long‐duration no‐choice assays to gauge the effectiveness of ITN treated with β‐cyfluthrin, λ‐cyhalothrin, and bifenthrin on face and house flies. Results After 12 wk in direct sunlight, ITN treated with β‐cyfluthrin was still highly insecticidal to face and house flies, producing 100% mortality in petri dish assays. However, sunlight reduced the insecticidal activity of λ‐cyhalothrin, with 3% of face flies and 50% of house flies surviving after exposure to ITN that had been deployed for 10 wks. Insecticidal activity was greatly reduced on bifenthrin‐treated netting, with 20% of face flies and 50% of house flies surviving in assays with netting deployed only 3 wks. Conclusion With careful choice of pyrethroid applied, treated netting could be an important component of livestock integrated pest management programs focused on sustainable practices.
  PubDate: 2013-03-19T08:24:22.41402-05:0
  DOI: 10.1002/ps.3537
Structure, bioactivity and implications for environmental remediation of complexes comprising the fungicide hexaconazole bound to copper
- Authors: Jin‐Hao Zhao; Sheng‐Hong Lai, Lu‐Lu Ruan, Jing‐Li Cheng, Cheng‐Xia Tan, Guo‐Nian Zhu
  Pages: n/a - n/a
  Abstract: Background In agricultural areas, Excessive toxic heavy metals are a growing threat to the environment and human health. Measures should be taken to minimize the risk of adverse health effects. Hence, we investigated the possibilities of hexaconazole (commercial fungicidal) as dual‐function ligands that have heavy metal ions chelating and fungicidal activities. Results Metal chelation and fungicidal activities were studied by UV, elemental analysis, IR, thermogravimetric study and biological assays. Results showed that hexaconazole had selective binding capability with Cu2+ over other ions such as Zn2+, Cd2+, Mn2+, Fe2+ and Co2+. Soil leaching experiments showed that soil type had limit effect on the heavy metal adsorption by hexaconazole; with the decreasing of pH, a notable rise of leaching effect was observed, reached 22%. In addition, this complex exhibit better fungicidal activity against Blumeria graminis than the same dose of hexaconazole. Conclusion Our study presented herein demonstrates that the hexaconazole had notable capabilities to chelate heavy metals as well as the excellent fungicidal activity as a metal chelator. Given the mutual influence between pesticides and heavy metals in adsorption−desorption processes, these phenomena must be taken into account if they are to be applied rationally.
  PubDate: 2013-03-19T08:20:24.534877-05:
  DOI: 10.1002/ps.3536
Improving the biocontrol potential of entomopathogenic nematodes against Mamestra brassicae: effect of spray application technique, adjuvants and an attractant
- Authors: Bert Beck; Eva Brusselman, David Nuyttens, Maurice Moens, Femke Temmerman, Sabien Pollet, Stephanie Van Weyenberg, Pieter Spanoghe
  Pages: n/a - n/a
  Abstract: Background Steinernema carpocapsae Weiser, an entomopathogenic nematode (EPN), is a potential biological control agent for the cabbage moth (Mamestra brassicae L.). This research aims at the identification of a suitable spray application technique; it determines whether yeast extract added to an EPN spray has an attracting and/or a feeding stimulant effect on M. brassicae and it examines the biological control capabilities of EPN against this pest in the field. Results Good coverage of the underside of cauliflower leaves, the habitat of young instar larvae (L1‐L4) of M. brassicae, was obtained using different spray boom configurations with vertical extensions that carried underleaf spraying nozzles. One of the configurations was selected for field testing with an EPN spray. Brewer's yeast extract stimulated larval feeding on leaves, and increased the mortality of these larvae when exposed to EPN. The field trial showed that a spray application with S. carpocapsae, Addit and xanthan gum can effectively lower the numbers of cabbage heads damaged by M. brassicae. Brewer's yeast extract did not significantly increase this field performance of EPN. Conclusion Steinernema carpocapsae, applied with an appropriate spray technique, can be used within biological control schemes as part of a resistance management programme for Bt.
  PubDate: 2013-03-19T08:09:42.144512-05:
  DOI: 10.1002/ps.3533
Evaluation of sulfuryl fluoride as a soil fumigant in China
- Authors: Aocheng Cao; Meixia Guo, Dongdong Yan, Liangang Mao, Qiuxia Wang, Yuan Li, Xiayu Duan, Peisheng Wang
  Pages: n/a - n/a
  Abstract: Background Root‐knot nematodes and soil‐borne diseases constrain the rapid development of protected agriculture in China, especially while phasing out methyl bromide (MB). Sulfuryl fluoride (SF) fumigant is currently used as a MB alternative for the disinfestation of buildings ans post‐harvest commodities. Our experiments aimed to evaluate a novel application of SF as a soil fumigant in greenhouses in China. Results Dose–response experiments indicated that SF has good efficacy on root‐knot nematodes (Meloidogyne spp.) and moderate activity against Fusarium spp. and weeds (Digitaria sanguinalis (L.) Scop.and Abutilon theophrasti Medicus). The field trials indicates that SF has good efficacy, between 80‐94%, on Meloidogyne spp., and Fusarium spp. at the rates of 25–50 g/m2 in tomato and cucumber in Beijing and Shandong Province. Marketable yield and plant vigor was not significantly different in SF and MB treatments. SF has lower emissions than MB during the fumigation operation. It is simple to apply, can be used at low temperature, and has a short plant‐back time. SF was found to be an economically feasible alternative to MB for nematode control in China. Conclusion SF can be used as a soil fumigant to control root‐knot nematodes and to reduce the levels of key soil pathogens.
  PubDate: 2013-03-19T08:06:26.324613-05:
  DOI: 10.1002/ps.3535
Analytical method for determination of meptyldinocap as 2,4‐dinitrooctylphenol metabolite in cucumber and soil using LC‐MS/MS and residues study in Chinese cucumber field ecosystem
- Authors: Zhiyong Zhang; Weili Shan, Qiu Jian, Wencheng Song, Yan Shen, Xianjin Liu
  Pages: n/a - n/a
  Abstract: Backgroud Meptyldinocap (2,4‐DNOPC) is a novel powdery mildew (Erysiphe necator) fungicide which shows protectant and post infective activities. But there is no reliable validated LC‐MS/MS method for measuring trace levels of meptyldinocap in cucumber. A method for determination of 2,4‐DNOPC using LC‐MS/MS in cucumber and soil was developed as well as its degradations and residue levels in cucumbers and soils were investigated. Results Recoveries of meptyldinocap from cucumber and soil samples were found to be 81.4%‐95.1%. The limits of quantification were found to be 0.01 mg/kg in cucumber and soil. The half‐lives of metpyldinocap in cucumbers and soils were in the ranges of 1.6 to 2.2 days and 3.1 to 4.4 days. The harvest residue levels of meptyldinocap in cucumbers and soils were in the ranges of below 0.01 mg/kg to 0.92 mg/kg and below 0.01 mg/kg to 0.53 mg/kg. 5 days after application, the harvest residue levels of meptyldinocap in cucumbers in all treatments were below 0.1 mg/kg. Conclusion Compared with the MRL for meptyldinocap in cucumber (0.1 mg/kg) was set by EU, so it is suggested that a pre‐harvest intervals of 5 days should be done at the recommended rate and times before harvest of cucumber.
  PubDate: 2013-03-15T11:20:52.415423-05:
  DOI: 10.1002/ps.3531
Economic and Policy Issues of U.S Agricultural Pesticide Use Trends
- Authors: Craig D. Osteen; Jorge Fernandez‐Cornejo
  Pages: n/a - n/a
  Abstract: Background This paper discusses U.S. agricultural pesticide use trends from 1964 to 2010 based on estimates developed from USDA surveys, and the influence of economic factors, agricultural policy, and pesticide regulation on aggregate quantities and mix of pesticides used. Results Synthetic organic pesticide use grew dramatically from the 1960's to the early 1980's, as farmers treated more and more acreage. Use then stabilized, with herbicides applied to about 95 percent of corn, cotton, and soybean acres, annually. Subsequently, major factors affecting trends were: 1) changes in crop acreage and other economic factors, 2) use of new pesticides that reduced per‐acre application rates and/or met more rigorous health and environmental standards, and 3) adoption of genetically engineered insect‐resistant and herbicide‐tolerant crops. Conclusion The use of pesticides and other control practices responded to economic factors such as input and output markets and agricultural policies. Changing societal values toward pesticide risks and benefits profoundly affected pesticide policy, influencing the pesticides available for use, but only indirectly affecting aggregate quantities used. While the current pesticide regulatory process might have economic inefficiencies, it might be consistent with policy preferences held by much of the public ‐‐ to reduce pesticide hazards rather than minimize regulatory costs.
  PubDate: 2013-03-08T15:12:25.423587-05:
  DOI: 10.1002/ps.3529
Modeling the fate of pesticides in paddy rice–fish pond farming systems in northern Vietnam
- Authors: Nguyen La; Marc Lamers, Vien V Nguyen, Thilo Streck
  Pages: n/a - n/a
  Abstract: Background In Vietnam, paddy rice fields have been identified as a major non‐point source of pesticide pollution of surface‐ and ground water which is often directly used for domestic purposes. One strategy to assess the risk of pesticide pollution is to use process‐based models. Here, we present a new model developed for simulating short‐term pesticide dynamics in combined paddy rice field ‐ fish pond farming systems. The model was calibrated using the Gauss‐Marquardt‐Levenberg algorithm and validated against measured pesticide concentrations of a paddy field‐fish pond system typical for northern Vietnam. Results In the calibration period, model efficiencies were 0.82 for dimethoate and 0.87 for fenitrothion. In the validation period, modeling efficiencies slightly decreased to 0.42 and 0.76 for dimethoate and fenitrothion, respectively. Scenario simulations revealed that a field closure period of one day after pesticide application considerably reduces the risk of pond and surface water pollution. Conclusion These results indicate that the proposed model is an effective tool to assess and evaluate management strategies, such as extended field closure periods, aiming to reduce the loss of pesticides from paddy fields.
  PubDate: 2013-03-08T15:05:15.909288-05:
  DOI: 10.1002/ps.3527
Behavioural avoidance and enhanced dispersal in neonicotinoid‐resistant Myzus persicae (Sulzer)
- Authors: Lucy M. Fray; Simon R. Leather, Glen Powell, Russell Slater, Eddie McIndoe, Robert J. Lind
  Pages: n/a - n/a
  Abstract: Background The peach potato aphid Myzus persicae is a major agricultural pest capable of transmitting over 100 plant viruses to a wide range of crops. Control relies largely upon treatment with neonicotinoid insecticides such as thiamethoxam (TMX). In 2009, a strain denoted FRC, was discovered in France which exhibits between 255–1679 fold resistance to current neonicotinoids previously linked to metabolic and target site resistance. Dispersal behaviour may potentially further enhance the resistance of this strain. This study investigated this possibility and is the first to compare the dispersal behaviour of aphid clones of the same species with differing levels of neonicotinoid resistance. Results Comparing the dispersal behaviour of the FRC strain with that of a clone of lower neonicotinoid resistance (5191A), and a susceptible clone (US1L) highlighted several differences. Most importantly, the FRC strain exhibited an increased ability to locate untreated areas when presented with an environment consisting of both TMX‐treated and untreated plant tissue. Conclusion The altered dispersal behaviour of the FRC may partially account for the high level of neonicotinoid‐resistance exhibited by this strain in the field. Since the dispersal of aphid vectors is key to the transmission of viruses across crop fields this has implications for current crop protection practise.
  PubDate: 2013-03-08T14:55:48.485194-05:
  DOI: 10.1002/ps.3530
Improving hybrid seed production in corn with glyphosate‐mediated male sterility
- Authors: Paul C.C. Feng; Youlin Qi, Tommy Chiu, Martin A. Stoecker, Christopher L. Schuster, Scott C. Johnson, Augustine E. Fonseca, Jintai Huang
  Pages: n/a - n/a
  Abstract: Background Hybrid corn varieties exhibit benefits associated with heterosis and account for most of the corn acreage in the USA. Hybrid seed corn is produced by crossing a female parent which is male‐sterile and therefore incapable of self‐pollination with a male parent as the pollen donor. The majority of hybrid seed corn is produced by mechanical detasseling which involves physically removing the tassel, a process that is laborious and costly. Results Glyphosate‐resistant corn was developed via expression of a glyphosate insensitive 5‐enolpyruvyl‐shikimate 3‐phosphate synthase enzyme (CP4‐EPSPS). Experimentation with molecular expression elements resulted in selective reduction of CP4‐EPSPS expression in male reproductive tissues. The resulting plant demonstrated sterile tassel following glyphosate application with little to no injury to the rest of the plant. Using 14C‐glyphosate as a marker, we also examined the translocation of glyphosate to the tassel via spray application in a track sprayer to simulate field application. The results allowed optimization of spray parameters such as dose, spray timing and target to maximize tassel delivery of glyphosate for efficient sterilization. Conclusion Roundup hybridization system (RHS) is a novel process for hybrid seed production based on glyphosate‐mediated male sterility. RHS replaces mechanical detasseling with glyphosate spray and greatly simplifies the process of hybrid seed corn production.
  PubDate: 2013-03-04T13:21:16.465218-05:
  DOI: 10.1002/ps.3526
Sublethal Effects of Four Neonicotinoid Seed Treatments on the Demography and Feeding Behaviour of the Wheat Aphid, Sitobion avenae
- Authors: Jin Miao; Zhen‐Bao Du, Yu‐Qing Wu, Zhong‐Jun Gong, Yue‐Li Jiang, Yun Duan, Tong Li, Chao‐Liang Lei
  Pages: n/a - n/a
  Abstract: Background Neonicotinoids are widely used as seed treatments in wheat fields against the grain aphid (Sitobion avenae F.) in China. Due to the degradation of neonicotinoids in wheat plants, wheat aphids are more likely to be exposed to low concentrations of neonicotinoids over long periods. It is therefore expected that neonicotinoids, aside from acute (lethal) effects, may also cause a range of sublethal effects on this pest. Results The growth and fertility of S. avenae feeding on wheat plants treated with a sublethal concentration (LC10) of imidacloprid, dinotefuran, thiacloprid and thiamethoxam were not greatly affected. However, the population growth parameters of S. avenae were significantly reduced at median lethal concentration (LC50). Electronic penetration graph (EPG) recordings showed a higher percentage of no probing phase and shorter phloem sap ingestion phase on the wheat plants treated with LC10 and LC50 concentrations. Conclusion The results indicate that even low concentrations of neonicotinoid treatments on wheat seeds have long‐term, adverse effects on wheat aphid. As such, neonicotinoid seed treatments have far greater effects on wheat aphids than estimated by acute toxicity tests. These results benefit our understanding on the subtle effects of the four tested neonicotinoids when applied as seed treatments.
  PubDate: 2013-03-01T15:55:19.563504-05:
  DOI: 10.1002/ps.3523
Real‐time PCR to study the effect of timing and persistence of fungicide application and wheat varietal resistance on Mycosphaerella graminicola and its sterol 14 α‐demethylation‐inhibitor‐resistant genotypes
- Authors: Sameh Selim; Céline Roisin‐Fichter, Jean‐Baptiste Andry, Boris Bogdanow, Renée Sambou
  Pages: n/a - n/a
  Abstract: Background Sterol 14α‐demethylase inhibitors (DMIs) have been widely used for more than 20 years against Wheat Septoria leaf blotch (SLB). However, resistance towards DMIs has increased in recent years. The objective of this study was to evaluate the effect of fungicide timing and persistence and wheat resistance varietal on Mycosphaerella graminicola and its DMIs‐resistant genotypes. Results Using qPCR, M. graminicola was detected two weeks later in the resistant cultivar than in the susceptible cultivar. A high proportion of DMIs‐moderate resistant genotypes (≥ 94%) was found in all samples, with an average of 74.2, 0.1 and 19.7% for R6, R7− and R7+ genotypes, respectively. Distribution of DMI‐resistant genotypes was neither affected by different wheat cultivars nor by analysis dates. Electron microscopy coupled with qPCR analysis showed that the DMI‐fungicide prothioconazole had a significant inhibitive effect against spore germination and postgermination. However, the preventive treatment was the most effective, but it was affected strongly by fungicide persistence. Conclusion Preventive fungicide applications are more effective against SLB than the curative treatments, so persistence and wheat varietal resistance should be taken into account in the management of this disease. It would seem that none of the studied factors affect the frequency of DMI‐resistant genotypes.
  PubDate: 2013-03-01T12:38:55.95858-05:0
  DOI: 10.1002/ps.3525
A resistance mechanism dependent upon the inhibition of ethylene biosynthesis
- Authors: Jiangyan Xu; Bo Lv, Qiong Wang, Jun Li, Liyao Dong
  Pages: n/a - n/a
  Abstract: Background The highly selective auxin‐type herbicide quinclorac is widely used to control important dicotyledon and monocotyledon weeds in rice fields. Echinochloa crusgalli var. zelayensis is one of the most troublesome weeds in China, and is very difficult to control in East China due to misuse of herbicides. Results The JZD‐R, JTJ‐R, JCW‐R and SSX‐R biotypes of E. crusgalli var. zelayensis had resistance to quinclorac with resistance levels ranked as JZD‐R < JTJ‐R < JCW‐R < SSX‐R. Growth reduction in different biotypes was positively correlated with ethylene production. Stimulated levels of ethylene and 1‐aminocyclopropane‐1‐carboxylic acid (ACC) and activities of ACC synthase and ACC oxidase in resistant biotypes were less than the susceptible biotype, and were negatively correlated with quinclorac resistance levels, suggesting that inhibition of ethylene biosynthesis was positively correlated with resistance levels. Conclusion Considering the resistance‐dependent inhibition in the ethylene biosynthetic pathway, the mechanisms of resistance to quinclorac in E. crusgalli var. zelayensis involved alteration(s) in the ethylene response pathway, consisting of at least alteration in induction of the enzymes activity of ACC synthase and ACC oxidase.
  PubDate: 2013-03-01T12:38:07.876084-05:
  DOI: 10.1002/ps.3524
Pleiotropic effects of herbicide‐resistance genes on crop yield: a review
- Authors: Henri Darmency
  Pages: n/a - n/a
  Abstract: The rapid adoption of genetically engineered herbicide‐resistant crop varieties (HRCV) — encompassing 83 % of all GM crops and nearly 8 % of the worldwide arable area — is due to technical efficiency and higher returns. Other herbicide‐resistant varieties obtained from genetic resources and mutagenesis have also been successfully released. Although the benefit for weed control is the main criteria for choosing HRCVs, the pleiotropic costs of genes endowing resistance have rarely been investigated in crops. Here the available data of comparisons between isogenic resistant and susceptible varieties are reviewed. Pleiotropic harmful effects on yield are reported in half of the cases, mostly with resistance mechanisms that originate from genetic resources and mutagenesis (atrazine in oilseed rape and millet, trifluralin in millet, imazamox in cotton) rather than genetic engineering (chlorsulfuron and glufosinate in some oilseed rape varieties, glyphosate in soybean). No effect was found for sethoxydim and bromoxynil resistance. Variable minor effects were found for imazamox, chlorsulfuron, glufosinate and glyphosate resistance. The importance of the breeding plan and the genetic background on the emergence of these effects is pointed out. Breeders’ efforts to produce better varieties could compensate for the yield loss, which eliminates any possibility of formulating generic conclusions on pleiotropic effects that can be applied to all resistant crops.
  PubDate: 2013-03-01T12:19:07.465734-05:
  DOI: 10.1002/ps.3522
A host‐plant‐derived volatile blend to attract the apple blossom weevil Anthonomus pomorum – the essential volatiles include a repellent constituent
- Authors: Jana Collatz; Silvia Dorn
  Pages: n/a - n/a
  Abstract: Background Plant volatiles are promising cues for trapping pest insects. This study started with a recently identified complex blend released by prebloom apple trees and aimed to reduce the number of compounds in the blend while maintaining the attraction of the target pest, the apple blossom weevil Anthonomus pomorum. An evaluation was made to determine whether attraction to plant volatiles is a general feature in this species. Results Laboratory‐based bioassays with field‐collected weevils demonstrated repellency by volatiles from the non‐host walnut, indicating that preference for plant odours is not a general feature in this species. By a subtractive bioassay approach, the original number of compounds in the apple‐plant‐released blend was stepwise reduced from 12 to 6 while maintaining weevil attraction. This resulting blend was as attractive as the full blend and as a blossom‐bud‐carrying apple twig. It was found to be composed of two synergistically interacting constituents, of which the first containing benzenoids was behaviourally inactive, and the second comprising the remaining compounds was even repellent. Conclusions This study enhances knowledge of the interaction of behaviourally effective constituents in complex odour blends and contributes to the development of an efficient monitoring system involving plant volatiles for the apple blossom weevil. © 2013 Society of Chemical Industry
  PubDate: 2013-02-28T07:25:33.284146-05:
  DOI: 10.1002/ps.3477
The sulfonylurea receptor Sur is dispensable for chitin synthesis in Drosophila melanogaster embryos
- Authors: Frauke Meyer; Matthias Flötenmeyer, Bernard Moussian
  Pages: n/a - n/a
  Abstract: Background Chitin produced by membrane‐inserted chitin synthases is an important constituent of the arthropod cuticle and midgut peritrophic matrix. Chitin synthesis inhibitors are common insecticides in pest control. As the target of sulfonylurea‐derived insecticides such as diflubenzuron, the ABC transporter sulfonylurea receptor (Sur) has been postulated to be an essential cofactor of chitin synthesis. However, direct evidence for this assumption is missing. Results Here, a study has been made of the phenotype of Drosophila melanogaster larvae suffering completely eliminated Sur function. Taken together, it is found that cuticle architecture is normal and chitin amounts are not diminished in the cuticle of these animals, indicating that Sur is dispensable for chitin synthesis. Conclusion The data obtained suggest that there must exist another sulfonylurea‐sensitive ABC transporter that either instead of Sur is the true sulfonylurea‐sensitive transporter involved in chitin synthesis or is able to substitute Sur function during cuticle formation. Identification and characterisation of this factor is pivotal for understanding the mode of action of sulfonylurea as insecticide.
  PubDate: 2013-02-26T05:05:56.777035-05:
  DOI: 10.1002/ps.3476
Sampling stored product insect pests: a comparison of four statistical sampling models for probability of pest detection
- Authors: David Elmouttie; Paul Flinn, Andreas Kiermeier, Bhadriraju Subramanyam, David Hagstrum, Grant Hamilton
  Pages: n/a - n/a
  Abstract: Background Developing sampling strategies to target biological pests such as insects in stored grain is inherently difficult due to species biology and behavioural characteristics. The design of robust sampling programmes should be based on an underlying statistical distribution which is sufficiently flexible to capture variations in the spatial distribution of the target species. Results We compare the accuracy of four probability of detection sampling models ‐ the negative binomial model,1 the Poisson model, 1 the double logarithmic model 2 and the compound model 3‐ to detect insects over a broad range of insect densities. Although the double log and negative binomial models performed well under specific conditions, we show that of the four models examined the compound model performed the best over a broad range of insect spatial distributions and densities. In particular, this model predicted well the number of samples required when insect density was high and clumped within experimental storages. Conclusions This paper reinforces the need for effective sampling programs that are designed to detect insects over a broad range of spatial distributions. The compound model is robust over a broad range of insect densities and leads to substantial improvement of detection probabilities within highly variable systems such as grain storage.
  PubDate: 2013-02-22T12:33:07.424103-05:
  DOI: 10.1002/ps.3469
Implications of European corn borer, Ostrinia nubilalis, infestation in an Aspergillus flavus‐biocontrolled corn agroecosystem
- Authors: Mariangela Mencarelli; Cesare Accinelli, Alberto Vicari
  Pages: n/a - n/a
  Abstract: Background A novel biocontrol strategy consisting of field application of bioplastic‐based granules inoculated with a non‐toxigenic Aspergillus flavus L. strain has recently been shown to be effective for reducing aflatoxin contamination in corn. This study focused on other factors that may affect the feasibility of this biocontrol technique, and more specifically the role of the European corn borer (ECB), Ostrinia nubilalis H., in the dispersal and infestation of A. flavus in corn and its impact on crop yield. Results In spite of the high percentage of corn ears showing larval feeding damage, ECB‐bored kernels accounted for only 3 and 4% in 2009 and 2010 respectively. Most of the damaged kernels were localised in the ear tip or immediately below. More precisely, the average incidence of ECB‐bored kernels in the upper end of the ear was 32%. However, less than 5% of kernels from the central body of the ear, which includes the majority of kernels, were injured by ECB. Conclusions Although ECB larvae showed a high tolerance to aflatoxin B1 and thus had the potential to serve as vectors of the mould, fungal infection of kernels was poorly associated with insect damage. ECB infestation resulted in grain yield losses not exceeding 2.5%. © 2012 Society of Chemical Industry
  PubDate: 2013-02-21T12:22:40.346102-05:
  DOI: 10.1002/ps.3472
Metabolism‐based synthesis, biological evaluation and structure–activity relationship analysis of spirotetramat analogues as potential lipid biosynthesis inhibitors
- Authors: Jing‐Li Cheng; Xing‐Rui He, Zong‐Cheng Wang, Jian‐Gong Zhang, Jin‐Hao Zhao, Guo‐Nian Zhu
  Pages: n/a - n/a
  Abstract: Background In previous studies, scientists found that, when spirotetramat was introduced into plants or animals, it was mainly metabolised at positions C‐4 and C‐8. That is to say, these two functional positions potentially played an important role in spirotetramat's bioactivities. In order to develop novel insecticides or miticides, the present authors designed and synthesised 35 spirotetramat analogues based on metabolite structures. Results All of the analogues have been identified on the basis of 1H NMR, ESI‐MS and elemental analysis data. The activities of these analogues were evaluated against three organisms, and biological assays indicated that compounds 5f, 5h and 5u possessed better insecticidal activities against bean aphids (Aphis fabae) than the lead compound spirotetramat. The LC50 of 5f, 5h and 5u against bean aphids reached 0.42, 0.28 and 2.53 mg L−1 respectively. Moreover, some compounds possessed comparable activities against carmine spider mite (Tetranychus cinnabarinus) and oriental armyworm (Mythimna sepatara) with spirotetramat. The structure–activity relationships (SARs) indicated that the flexible bridge at position C‐4 of spirotetramat was important for its bioactivities, and the size of the group at position C‐8 would have great influence on the activities. Furthermore, the log P values lower than 6.0 may be favourable for insecticidal activities. Conclusion The present work demonstrates that some spirotetramat analogues can be used as potential lead compounds for developing novel insecticides, and preliminary SAR analysis would provide information for the utilisation of spirotetramat analogues as potential lipid biosynthesis inhibitors. © 2012 Society of Chemical Industry
  PubDate: 2013-02-21T11:15:30.642185-05:
  DOI: 10.1002/ps.3473
Further research on the biological function of inclusion bodies of Anomala cuprea entomopoxvirus with special reference to effect on the insecticidal activity of a Bacillus thuringiensis formulation
- Authors: Wataru Mitsuhashi; Shoji Asano, Kazuhisa Miyamoto, Sanae Wada
  Pages: n/a - n/a
  Abstract: Background Entomopoxviruses (EVs) form two types of inclusion bodies: spheroids, which contain virions, and spindles, which do not. We tested whether the spindles from a coleopteran EV, Anomala cuprea EV (ACEV), enhanced the insecticidal activity of a commercial Bacillus thuringiensis (Bt) formulation and the susceptibility of scarabaeid pest species in Japan to the virus's spheroids, to assess whether ACEV inclusion bodies are potential biological control agents for pest insects. Results Peroral inoculation of both ACEV spindles and the Bt toxin only or the complete Bt formulation shortened the survival and increased the mortality of treated insects compared with those of insects inoculated with Bt without the spindles (8–38 hours of decrease in LT50 values among assays). ACEV showed high infectivity to a major scarabaeid pest species in Japanese sugar cane fields. Conclusion Our results suggest that spindles or the constituent protein, fusolin, can be used as a co‐agent with Bt formulations and that fusolin co‐expression with a Bt toxin in crops might improve the insecticidal efficacy. In addition, the spheroids are potential bio‐control agents for some scarabaeid pests that are not easy to control because of their underground habitation.
  PubDate: 2013-02-19T12:49:51.297278-05:
  DOI: 10.1002/ps.3521
Predicting Emergence of Codling Moth, Cydia pomonella (Lepidoptera: Tortricidae) on a Degree‐Day Scale in North America
- Authors: Vincent P Jones; Richard Hilton, Jay F Brunner, Walt J Bentley, Diane G Alston, Bruce Barrett, Robert A Van Steenwyk, Larry A Hull, James F Walgenbach, William W Coates, Timothy J Smith
  Pages: n/a - n/a
  Abstract: Background Codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), is a major pest of apple, pear, and walnut production in North America. Management programs are based on preventing larval entry into the fruit or nut and are typically timed by heat‐driven models that are synchronized to field populations by first capture of overwintering moths in pheromone traps. Unfortunately, trap capture is affected by a range of environmental parameters as well as by the use of mating disruption, which makes detecting first flight difficult, thus complicating implementation of management programs. Our goal was to evaluate data collected from a broad range of locations across North America to see if we could predict average first spring emergence times. Results Average emergence time on a degree‐day scale from 1 January was predictable using latitude and elevation. Sites at elevations
  PubDate: 2013-02-19T12:48:08.503513-05:
  DOI: 10.1002/ps.3519
Insecticidal and Biting Deterrent Activity of Rose‐scented Geranium (Pelargonium spp.) Essential Oils and Individual Compounds Against Stephanitis pyrioides and Aedes aegypti
- Authors: Abbas Ali; Christine C. Murphy, Betul Demirci, David E. Wedge, Blair J. Sampson, Ikhlas A. Khan, K.Husnu Can Baser, Nurhayat Tabanca
  Pages: n/a - n/a
  Abstract: Background Rose‐scented geranium, Pelargonium spp., essential oils from the cultivars ‘Bourbon’, ‘China’, ‘Egypt’, ‘Rober's Lemon Rose’ and ‘Frensham’ were analyzed by GC‐FID and GC‐MS. One‐hundred and thirty six compounds were identified from five essential oils, which constituted 85.5% to 99.7% of the oils. Essential oils and pure compounds were evaluated for their insecticidal activity against Stephanitis pyrioides and larvicidal and biting deterrent activity against Aedes aegypti. Results All five geranium oils were toxic to S. pyrioides and four of these five were more potent than malathion and neem. Trans‐nerolidol (LD50=13.4 ppm) was the most toxic compound against 1‐d‐old Ae. aegypti larvae followed by geraniol (49.3 ppm), citronellol (49.9 ppm) and geranyl formate (58.5 ppm). Essential oil of cultivar ‘Egypt’ at 100 µg/cm2 (BDI=0.8) showed the highest biting deterrent activity followed by cultivars ‘Frensham’ (BDI=0.76); ‘China’ (BDI=0.72); ‘Rober's Lemon Rose’ (BDI=0.63) and ‘Bourbon’ (BDI=0.45) essential oils. Among the pure compounds, biting deterrent activity of geranic acid (BDI=0.99) was not significantly different than DEET. Conclusion Essential oils and pure compounds showed insecticidal activity against S. pyrioides and Ae. aegypti. High biting deterrent activity of geranic acid points to the need of further research.
  PubDate: 2013-02-19T11:48:28.050345-05:
  DOI: 10.1002/ps.3518
Lethal and sub‐lethal effects of cantharidin on life history traits and population parameters of Helicoverpa armigera (Hub) (Lepidoptera: Noctuidae)
- Authors: R. A. Khan; M. Rashid, D. Wang, Y.L. Zhang
  Pages: n/a - n/a
  Abstract: Background Cotton bollworm, Helicoverpa armigera hub. is a serious and cosmopolitan pest of many economic crops. Its control has not been adequate due to its resistance to many groups of insecticides. Toxicity of cantharidin on armyworm and diamondback moth has already been reported. However, its toxicity on H. armigera has not been investigated previously. In this study, we report lethal and sub‐lethal effects of cantharidin on H. armigera under laboratory conditions. Results Our results showed gross abnormalities in population parameters of H. armigera, ranging from larvae to adults. Reduction in larval weight and wings malformation was observed in cantharidin‐treated population cohort. Comparatively, higher mortality at larval, pupal and adult stages was observed in cantharidin‐treated, compared to control. Almost five times less fecundity was recorded in treated population cohort. Fertility was also severely affected and reduction in all population parameters was observed. Conclusion Cantharidin in our study caused larval mortality and other serious abnormalities in H. armigera population parameters and therefore, may have positive implications for pest management decision making process. More interestingly, our experiment revealed that cantharidin in sub‐lethal dose mimicked (Insect Growth Regulator) IGR insecticides. Furthermore, cantharidin could be used as a precursor compound for the synthesis of new analogues and compounds to replace ineffective older compounds.
  PubDate: 2013-02-19T11:29:36.319534-05:
  DOI: 10.1002/ps.3517
Cross‐resistance to prosulfocarb and triallate in pyroxasulfone‐resistant Lolium rigidum
- Authors: Roberto Busi; Stephen B Powles
  Pages: n/a - n/a
  Abstract: Background Plants can rapidly evolve resistance to herbicide in response to repeated selection. This study focuses on cross‐resistance patterns observed in Lolium rigidum following pyroxasulfone recurrent selection. Results The parental MR (multi‐resistant) population following four generation of pyroxasulfone recurrent selection evolved cross‐resistance to prosulfocarb and triallate. At the recommended label rate of prosulfocarb or triallate (2000 g ha‐1) the four‐time pyroxasulfone‐selected progeny MR4 displayed 58% and 35% plant survival, respectively. One additional cycle of prosulfocarb selection increased the resistance level to both prosulfocarb and triallate in the population MR4‐P1. Prosulfocarb resistance is yet to be reported in L. rigidum field populations. Conclusions This study suggests that L. rigidum plants can rapidly evolve cross‐resistance to several wheat‐selective herbicides under recurrent selection of a single mode of action. Weed populations displaying broad‐spectrum cross‐resistance to several herbicide modes of action are increasing in frequency in intensive world agriculture. Proactive and integrated measures for resistance management need to be developed globally on appropriate herbicide use in crop rotations.
  PubDate: 2013-02-19T11:27:36.21338-05:0
  DOI: 10.1002/ps.3516
First molecular genotyping of insensitive acetylcholinesterase associated with malathion resistance in Culex quinquefasciatus Say populations in Malaysia
- Authors: Van Lun Low; Chee Dhang Chen, Phaik Eem Lim, Han Lim Lee, Yvonne Ai Lian Lim, Tiong Kai Tan, Mohd Sofian‐Azirun
  Pages: n/a - n/a
  Abstract: Background Granted that there is limited available information on the insensitive acetylcholinesterase in insect species in Malaysia, the present study aims to detect the presence of G119S mutation in acetylcholinesterase gene of Culex quinquefasciatus from 14 residential areas across 13 States and a federal territory in Malaysia. Results The ace‐1 sequence and PCR‐RFLP test revealed the presence of glycine‐serine ace‐1 mutation in the wild populations of Cx. quinquefasciatus. Both direct sequencing and PCR‐RFLP methods demonstrated similar results and revealed the presence of heterozygous genotype at a very low frequency (18 out of 140 individuals) while homozygous resistant genotype was not detected across all study sites in Malaysia. In addition, statistical analysis also revealed that malathion resistance is associated with the frequency of ace‐1R in Cx. quinquefasciatus populations. Conclusion This study has demonstrated the first field‐evolved instance of G119S mutation in Malaysian populations. Molecular identification of insensitive acetylcholinesterase provides significant insights into the evolution and adaptation of the Malaysian Cx. quinquefasciatus populations.
  PubDate: 2013-02-13T07:00:50.215071-05:
  DOI: 10.1002/ps.3512
Induced‐over‐expression of cytochrome P450 sterol 14α‐demethylase gene (CYP51) correlates sensitivity to demethylation inhibitors (DMIs) in Sclerotinia homoeocarpa
- Authors: Bangya Ma; Lane P. Tredway
  Pages: n/a - n/a
  Abstract: Background The fungus Sclerotinia homoeocarpa causes dollar spot, the most important turfgrass disease worldwide. Demethylation Inhibitor (DMI) fungicides have been relied upon heavily to manage this disease. Presently, populations of S. homoeocarpa with reduced sensitivity or resistance to DMIs are widespread in the U.S. Results Cytochrome P450 sterol 14α‐demethylase (ShCYP51), and its flanking regions were identified and sequenced in 29 isolates of S. homoeocarpa with a range of DMI sensitivities. No modifications were found in the gene coding and upstream regions that were consistently related to DMI sensitivity. In absence of propiconazole, ShCYP51 was expressed in a similar low level among DMI baseline and resistant isolates. In the presence of propiconazole, DMI resistant isolates were induced to express ShCYP51 at significantly higher levels than baseline isolates by propiconazole at 5 mg L‐1 for 5 h or at 0.5 mg L‐1 for 72 h. ShCYP51 expression level after 72 h exposure to 0.5 mg L‐1 propiconazole was linearly related to EC50 values and ΔRG (the change in relative growth rate over time) with R2 values equal to 83.7% and 90.0%, respectively. Conclusion Induced‐over‐expression of ShCYP51 in resistant isolates following DMI exposure is an important factor determining DMI sensitivity in S. homoeocarpa.
  PubDate: 2013-02-13T06:53:32.320276-05:
  DOI: 10.1002/ps.3513
Factors influencing the efficacy of two organophosphate insecticides in controlling California red scale, Aonidiella aurantii (Maskell). A basis for reducing spray application volume in Mediterranean conditions
- Authors: Cruz Garcerá; Enrique Moltó, Patricia Chueca
  Pages: n/a - n/a
  Abstract: Background Because our society is seeking ways to lessen the environmental impact of agricultural activity, dose adjustment has become a key issue in current plant protection treatments with high spray application volumes, such as citrus plants. This work investigates, in field conditions, the factors affecting the efficacy of organophosphate insecticides against California red scale (CRS), Aonidiella aurantii (Maskell), when the delivery rate is decreased. Insecticide rate changes were induced by modifying the spray application volumes of two commercial organophosphate pesticides that are based on chlorpyrifos and chlorpyrifos‐methyl. Results Results showed that with increases in the spray volume, the coverage and the uniformity of deposition on the canopy increased, but final infestation depended neither on the spray application volume nor on the coverage. Furthermore, final infestation significantly depended on the pest pressure in the plot and the spray volume applied per unit volume of canopy (l m‐3 canopy). Moreover, we found that the final infestation was influenced by the efficiency of deposition in the applications that were carried out against the second‐generation of CRS. Conclusion Because the spray application volume did not affect the final infestation, this research introduces the possibility that reducing the doses of current citrus organophosphate treatments may still allow effective plant protection in Mediterranean conditions.
  PubDate: 2013-02-13T06:51:43.088256-05:
  DOI: 10.1002/ps.3515
A sequential binomial sampling plan for potato psyllid (Hemiptera: Triozidae) on bell pepper (Capsicum annum)
- Authors: Sean M Prager; Casey D Butler, John T Trumble
  Pages: n/a - n/a
  Abstract: Background Potato psyllids (Bactericera cockerelli Sulc) are a pest on solanaceous crop plants, including bell peppers. Potato psyllids vector Candidatus Liberibacter psyllaurous, but bell peppers (Capsicum annum L.) do not exhibit symptoms from infection. Potato psyllids show variation in spatial patterns and host choice with cultivar and plant species. Consequently, a study of spatial distribution and sampling plan specific to bell peppers is necessary for management of this insect pest, as those developed for other crops are unlikely to transfer among crops. Results Potato psyllids were evenly distributed on both sides of leaves but prefer the top two‐thirds of pepper plants. Within fields, psyllids demonstrated an aggregated spatial distribution, but the edge effect observed in other crop plants was absent. Eggs and nymphs had similar spatial distributions that differed from adults. A series of nymph‐based sampling plans were examined. Sampling plans based on an infestation of less than 41% of plants infested (5 nymphs plant−1) were statistically unacceptable, while little difference was found between the 41% infestation plan and 56% (20 nymphs plant−1) infestation plan. At 41%, an average of 11 and maximum of 49 samples would be necessary to make a treatment decision. Conclusion The binomial sequential sampling plan presented here offers an important yet simple tool for managing potato psyllids in bell pepper. © 2012 Society of Chemical Industry
  PubDate: 2013-02-12T06:21:04.164462-05:
  DOI: 10.1002/ps.3475
Ecotoxicological characterisation of a mycoherbicide mixture isolated from the fungus Ascochyta caulina
- Authors: Pietro Fumagalli; Anna Andolfi, Fabiana Avolio, Angela Boari, Alessio Cimmino, Antonio Finizio
  Pages: n/a - n/a
  Abstract: Background Recent studies have highlighted the possibility of using a mixture of three fungal toxins produced by Ascochyta caulina as a bioherbicide to control noxious weeds. However, to assess the commercial potential of this new bioherbicide, it is necessary to increase knowledge regarding the environmental behaviour of these toxins, and particularly their effects on non‐target organisms. A negative ecotoxicological profile of this potential bioherbicide could eventually hinder its registration. Results In this study, acute and chronic effects of the A. caulina toxins (ACTs) on non‐target organisms were evaluated in the laboratory. The (96 h) calculated algal ErC50 and NOEC were 142.7 and 1000 and ≥250 mg kg−1 soil respectively. Conclusions The present study has provided baseline information needed to assess the potential hazard of the fungal toxins of A. caulina. In particular, the acute and chronic effects on aquatic (algae, Daphnia and fish) and terrestrial organisms (earthworms) have been highlighted. Finally, a comparison of the inherent toxicity of ACTs with other synthetic herbicides has shown comparative ecotoxicity of the tested mixture. © 2012 Society of Chemical Industry
  PubDate: 2013-02-08T12:06:32.951906-05:
  DOI: 10.1002/ps.3447
Asian corn borer (ACB) and non‐ACB pests in GM corn (Zea mays L.) in the Philippines
- Authors: Miladis M Afidchao; CJM Musters, Geert R Snoo
  Pages: n/a - n/a
  Abstract: Background The Asian corn borer (ACB), Ostrinia furnacalis (Guenée), has become the most damaging pest in corn in south‐east Asia. Corn farmers in the Philippines have incurred great yield losses in the past decades because of ACB infestation. Bacillus thuringiensis (Bt) and Bt herbicide‐tolerant (BtHT) corns have been developed to reduce borer attacks worldwide. This study assessed the extent of ACB and non‐ACB pest infestations in both GM and non‐GM corn in Isabela Province, the Philippines. Specific aims were to reinvestigate the efficacy of Bt corn in controlling ACB, to evaluate what parts of Bt corn plants are susceptible to ACB, to monitor the potential development of ACB resistance and to evaluate whether secondary pests dominate in an ACB‐free Bt corn environment. The study involved preparatory interviews with farmers, site selection, field scouting and visual inspection of 200 plants along 200 m transect lines through 198 cornfields. Results Bt corn can efficiently reduce the ACB pest problem and reduce borer damage by 44%, to damage levels in Bt and BtHT corn of 6.8 and 7% respectively. The leaves of Bt corn were more susceptible, while cobs of Bt corn were less affected by ACB. Non‐ACB pests were common in Bt toxin‐free cornfields and reduced in non‐GM cornfields where ACB was abundant. No secondary pest outbreaks were found in ACB‐free Bt cornfields. Conclusion Bt and BtHT corn hybrids containing the Cry1Ab protein performed well in Isabela Province. Reduced cob damage by ACB on Bt fields could mean smaller economic losses even with ACB infestation. The occurrence of ACB in Bt and BtHT cornfields, although at a moderate and insignificant level, could imply the potential development of resistance to Bt toxin. © 2012 Society of Chemical Industry
  PubDate: 2013-02-08T12:06:22.985169-05:
  DOI: 10.1002/ps.3471
Efficacy of Sulfuryl Fluoride against the Pinewood Nematode, Bursaphelenchus xylophilus (Nematoda: Aphelenchidae), in Pinus pinaster Aiton boards
- Authors: Luis F Bonifácio; Edmundo Sousa, Pedro Naves, Maria L Inácio, Joana Henriques, Manuel Mota, Pedro Barbosa, Mike J Drinkall, Stan Buckley
  Pages: n/a - n/a
  Abstract: Background The pinewood nematode (PWN) Bursaphelenchus xylophilus is an important conifer disease worldwide and the direct cause of death of millions of pines in Southeast Asia (mainly Japan, China and Korea), and has been established in Portugal since 1999. The phasing out of methyl bromide has created an urgent need for alternative treatment of wood‐packaging materials. The effect of sulfuryl fluoride (SF), a broad‐spectrum fumigant used to control insects, was tested against PWN naturally infested Pinus pinaster boards. Results Boards were fumigated for 24 hours at three different temperatures (15, 20 and 30°C) and the range of dosages were 3,169 – 4407 g‐h/m3, 1,901 – 4051 g‐h/m3 and 1,385 – 2141 g‐h/m3, respectively. Treated wood was sampled for nematode identification and counting, before treatment and after 24 hrs, 72 hrs and 21 days. No survival was found at the 15°C and 30°C treatments, while at 20°C mortality ranged between 94.06% and 100%. Some reasons for the survival at 20°C are presented. Conclusion Results confirm SF to be an effective quarantine treatment for PWN at 15°C and 30°C. Further studies are needed to obtain the most effective dosage at 20°C and complement temperature range with 25°C, for ISPM‐15 inclusion.
  PubDate: 2013-02-08T10:52:33.846905-05:
  DOI: 10.1002/ps.3507
Expression of Cry1Ac in transgenic Bt soybean lines and their efficiency in controlling lepidopteran pests
- Authors: Huilin Yu; Yunhe Li, Xiangju Li, Jörg Romeis, Kongming Wu
  Pages: n/a - n/a
  Abstract: Background Two transgenic lines of the soybean Glycine max, ‘MON87701’ expressing the Cry1Ac protein, and ‘MON87701RR2Y’ expressing Cry1Ac + EPSPS proteins were evaluated for their resistance to four lepidopteran pests in the laboratory using detached‐leaf bioassays throughout the soybean growth seasons (before anthesis, during anthesis and after anthesis) in China. Enzyme‐linked immunosorbent assays (ELISA) were used to monitor the Cry1Ac expression in soybean leaves. Results The bioassay results revealed that both transgenic soybean lines exhibited significantly high resistance against Helicoverpa armigera (Hübner) throughout the soybean growing seasons. The survival rates of H. armigera larvae ranged from 5.4‐24.4% when feeding on the transgenic soybean leaves that were significantly lower than those when feeding on control leaves with survival rates of 71.1‐94.9%. Limited resistance were found for both transgenic soybean lines against Spodoptera litura (Fabricius), although the survival rates and weight of S. litura larvae as well as female fecundity were significantly decreased when feeding on Bt soybean leaves compared to those feeding control leaves. In contrast, both transgenic soybean lines provide almost no resistance to Spodoptera exigua (Hübner) and Agrotis ypsilon (Rottemberg). Cry1Ac expression in the leaves of both transgenic soybean lines were relatively stable throughout the soybean growing season with a peak occurring at V6‐8 and V11‐12 before anthesis. The ELISA results were positively correlated with the results from the insect bioassays. Conclusions The results show that while Cry1Ac‐expressing Bt soybeans may provide good protection against H. armigera, alternative control measures are required to manage S. exigua, S. litura, and A. ypsilon.
  PubDate: 2013-02-08T10:40:28.116788-05:
  DOI: 10.1002/ps.3508
Lethality of reduced‐risk insecticides against plum curculio (Coleoptera: Curculionidae) in blueberries, with emphasis on their curative activity
- Authors: Cesar R. Rodriguez‐Saona; John C. Wise, Dean Polk, Tracy C. Leskey, Christine Vandervoort
  Pages: n/a - n/a
  Abstract: Background Historically, management of plum curculio, Conotrachelus nenuphar (Herbst), in highbush blueberries has focused on post‐bloom broad‐spectrum insecticide applications targeting the adults. Here, we compared the efficacy of different classes of insecticides against various stages of C. nenuphar, and tested a combination of a pre‐bloom treatment of the chitin synthesis inhibitor novaluron with a post‐bloom insecticide application. Results Novaluron decreased the number of oviposition scars and eggs on fruit, and reduced larval emergence by > 60% when applied pre‐bloom. Post‐bloom applications of the oxadiazine indoxacarb and the organophosphate phosmet, but not the neonicotinoid acetamiprid, showed significant adulticidal activity. The neonicotinoids acetamiprid and thiamethoxam and phosmet showed significant curative activity on C. nenuphar larvae when applied topically to infested fruit, whereas the pyrethroid fenpropathrin, indoxacarb, and novaluron were weaker curative agents. Residue profiles showed that acetamiprid and phosmet residues had the highest, while fenpropathrin and novaluron had the lowest, levels of fruit penetration. Conclusions In blueberries, novaluron showed anti‐ovipositional/ovicidal activity; indoxacarb and phosmet showed adulticidal activity; while the neonicotinoids and phosmet showed best curative (larvicidal) control on C. nenuphar. A pre‐bloom novaluron application in combination with a post‐bloom treatment of an adulticidal/larvicidal insecticide is recommended for optimal multi‐lifestage management of C. nenuphar.
  PubDate: 2013-02-08T10:39:20.985619-05:
  DOI: 10.1002/ps.3509
Area‐wide management of Aedes albopictus: II. Gauging the efficacy of traditional integrated pest control measures against urban container mosquitoes
- Authors: Dina M. Fonseca; Isik Unlu, Taryn Crepeau, Ary Farajollahi, Sean P. Healy, Kristen Bartlett‐Healy, Daniel Strickman, Randy Gaugler, George Hamilton, Daniel Kline, Gary G. Clark
  Pages: n/a - n/a
  Abstract: Background Aedes (Stegomyia) albopictus (Skuse) is an important disease vector and biting nuisance. During the 2009 active‐season we studied six approximately 1,000‐parcel sites, three in urban and three in suburban areas of New Jersey, USA, to examine the efficacy of standard integrated urban mosquito control strategies applied area‐wide. We implemented active source reduction, larviciding, adulticiding, and public education (source reduction through education) in one site in each county, developed an education‐only approach in the second site, and used the third site as an untreated experimental control. We surveyed populations weekly with BG‐Sentinel‐traps and ovitraps. Results We achieved a substantial reduction in Ae. albopictus populations in urban sites but only modest reductions in suburban sites. Education alone achieved significant reductions in urban adult Ae. albopictus. Egg catches echoed adult catches only in suburban sites. Conclusions There are significant socio‐economic and climatic differences between urban and suburban sites that impact Ae. albopictus populations and the efficacy of the control methods we tested. An integrated pest management approach can affect abundances but labor‐intensive costly source‐reduction was not enough to maintain Ae. albopictus counts below a nuisance threshold. Night‐time adult population suppression using truck‐mounted adulticides can be effective. Area‐wide cost‐effective strategies are necessary.
  PubDate: 2013-02-08T10:37:00.557385-05:
  DOI: 10.1002/ps.3511
Dietary chlorantraniliprole suppresses reproduction in worker bumblebees
- Authors: Guy Smagghe; Janna Deknopper, Ivan Meeus, Veerle Mommaerts
  Pages: n/a - n/a
  Abstract: Background Pollinators such as the bumblebee, Bombus terrestris, fulfil a crucial role in agriculture. In this context, tests were conducted with the insecticide chlorantraniliprole (Coragen®) as a model compound active on the ryanodine receptor of insects. Results Chronic oral exposure via pollen induced lethargic behaviour in B. terrestris workers and their offspring (drones). Indeed, in nests exposed to 0.4 mg l‐1, representing 1/100 of the concentration recommended for use in the field, workers and drones did not take their defensive position upon stimulation and they were less active than non‐exposed insects. The different risk assessment tests used here demonstrated that contact and pollen exposure had no effect on bumblebee worker survival, whereas oral exposure via sugar water caused both acute (72 h‐LC50=13 mg l‐1) and chronic (7 wk‐LC50=7 mg l‐1) toxicity. Severe sublethal effects on reproduction were recorded in nests orally exposed to pollen treated with chlorantraniliprole. Conclusion The present study identified an important physiological endpoint of sublethal effects on reproduction, as this is associated with lethargic behaviour after oral intake. As such, this is a factor that should now be incorporated into future risk assessments. Secondly, it confirmed that the assessment of sublethal effects on behaviour is needed for the adequate risk assessment of “potentially deleterious” compounds with a neurogenic target, as is also pointed out in the recent European Food Safety Authority (EFSA) guidelines.
  PubDate: 2013-02-05T13:10:36.17679-05:0
  DOI: 10.1002/ps.3504
Involvement of superoxide dismutase in oxidative stress in the oriental fruit fly, Bactrocera dorsalis: Molecular cloning and expression profiles
- Authors: Xue‐Meng Gao; Fu‐Xian Jia, Guang‐Mao Shen, Hua‐Qin Jiang, Wei Dou, Jin‐Jun Wang
  Pages: n/a - n/a
  Abstract: Background Bactrocera dorsalis, one of the most economically important fruit fly pests in East Asia, is well adapted to various environmental conditions. Pesticides, pathogens and other stresses can cause oxidative damage in most organisms. The SOD family contains some of the most important enzymes in the antioxidant protection system of the fruit fly and other organisms. Results Four full‐length cDNA sequences encoding one MnSOD (BdSOD2‐1) and three Cu‐ZnSODs (BdSOD1‐1, BdSOD1‐2, and BdSOD1‐3) were cloned. The expression profiles of these four genes under different stresses showed them to be involved in response to detrimental conditions including heavy metals, pesticides, extreme temperatures, and LPS stresses. More specifically, the expression levels of these genes were found to be depressed in the presence of copper, zinc, and manganese. The expression of all four SOD genes increased upon exposure to lead, cadmium, low temperature (0oC), and LPS stresses. Only BdSOD1‐3 transcription increased significantly at high temperature (40oC) exposure. The expressions levels of BdSOD1‐2 and BdSOD1‐3 increased significantly in the presence of β‐cypermethrin and malathion, but only the expression of BdSOD2‐1 increased in the presence of avermectin treatment. Conclusion These different expression profiles suggest that the four BdSODs play different roles and respond to different oxidative stresses in B. dorsalis. Some BdSODs undergo specific reaction in the response to specific oxidative stresses.
  PubDate: 2013-02-05T13:08:36.407526-05:
  DOI: 10.1002/ps.3503
Variation in selection and utilization of host crops in the field and laboratory by Drosophila suzukii Matsumara (Diptera: Drosophilidae), an invasive frugivore
- Authors: Hannah J. Burrack; Gina E. Fernandez, Taylor Spivey, Dylan A. Kraus
  Pages: n/a - n/a
  Abstract: Background Drosophila suzukii, a pest of soft skinned berries and stone fruits, has recently rapidly expanded its global range. The impacts of D. suzukii infestation and subsequent fruit damage in North America and Europe have been profound. The aim of our work was to assess host selection of D. suzukii in the field and laboratory with an emphasis on hosts commonly grown in the southeastern United States, where D. suzukii has been established since 2010. Results Raspberries were infested at a greater rate than blackberries in the field, and that varieties within both species were infestated at different rates. Primocane fruiting blackberries were often the least heavily infested. Further, blackberries and raspberries grown under high tunnels were infested at lower rates than those grown outside. Fruit and artificial substrates with a lower surface penetration force were more heavily infested than firmer substrates in the laboratory; no eggs were laid in artificial substrates exceeding 52.00 cN surface penetration force. Conclusion Infestation rates differ between species and varieties within species of Rubus in the southeastern United States. Fruit penetration force is one potential measure of host susceptibility, but host attractiveness will likely depend upon additional factors, such as soluble sugar content.
  PubDate: 2013-02-05T12:54:18.125404-05:
  DOI: 10.1002/ps.3489
Cyflumetofen, a novel acaricide – its mode of action and selectivity
- Authors: Naotaka Hayashi; Yasuhiro Sasama, Nobuyoshi Takahashi, Naoki Ikemi
  Pages: n/a - n/a
  Abstract: Background Cyflumetofen is a novel acaricide developed by Otsuka AgriTechno Co., Ltd. It affects only spider mites and has no effect on insects, crustaceans or vertebrates under conditions of practical use. The mode of action of cyflumetofen, its selectivity for mites and its safety for insects and vertebrates were investigated. Results The research showed that cyflumetofen inhibited mitochondria complex II in mites. In addition, the de‐esterified form (AB‐1) of cyflumetofen inhibited mitochondria complex II at extremely low concentrations. AB‐1 was also detected as the main metabolite in mites. Conclusion The mode of action of cyflumetofen is to inhibit mitochondria complex II by affecting its action site after being metabolised to AB‐1. However, inhibition by cyflumetofen and AB‐1 in other organisms was very weak. Selectivity for other organisms has contributed to differences in action site activities. © 2012 Society of Chemical Industry
  PubDate: 2013-02-05T05:56:20.975564-05:
  DOI: 10.1002/ps.3470
Comparison of multiple steam treatment durations for control of bed bugs (Cimex lectularius L.)
- Authors: Robert T Puckett; Danny L McDonald, Roger E Gold
  Pages: n/a - n/a
  Abstract: Background The factors contributing to the current resurgence of bed bug Cimex lectularius L. populations across the United States and elsewhere include, among others, the development of resistance to chemical insecticides and population management practices. This has led to the development and attempted refinement of many non‐chemical control methods that contribute to an IPM approach to solving the current bed bug population density increase in urban dwellings. One such approach is the use of heat in the form of steam to provide an effective mechanism for controlling localized infestations of bed bugs. Results The work reported herein was designed to refine our understanding of the duration of bed bug/steam contact necessary to affect mortality of bed bugs in laboratory trials. Beg bug eggs, nymphs and adults were exposed to three steam treatment exposure periods in these trials. Mean percentage mortality of bed bug eggs was 100% (regardless of duration of exposure), and that of nymphs and adults ranged from 88.0 to 94.0%. Survivorship of nymphs and adults in the trials was the result of experimental protocol restrictions that would not usually be associated with actual pest management efforts. Conclusions The treatment equipment used in these trials is portable and relatively inexpensive and represents a non‐chemical means of killing all life stages of bed bugs. While this method would likely be seen as an inefficient means of remediating a mature bed bug infestation within a structure, it does represent a practical component of integrated management of this pest insect. © 2012 Society of Chemical Industry
  PubDate: 2013-02-01T07:15:11.442319-05:
  DOI: 10.1002/ps.3467
Genome‐wide analysis of genes associated with moderate and high DDT resistance in Drosophila melanogaster
- Authors: Xinghui Qiu; Weilin Sun, Cynthia M McDonnell, Hongmei Li‐Byarlay, Laura D Steele, Jing Wu, Jun Xie, William M Muir, Barry R Pittendrigh
  Pages: n/a - n/a
  Abstract: Background Moderate to high DDT resistance in generally associated with overexpression of multiple genes and therefore has been considered to be polygenic. However, very little information is available about the molecular mechanisms that insect populations employ when evolving increased levels of resistance. The presence of common regulatory motifs among resistance‐associated genes may help to explain how and why certain suites of genes are preferentially represented in genomic‐scale analyses. Results A set of commonly differentially expressed genes associated with DDT resistance in the fruit fly was identified on the basis of genome‐wide microarray analysis followed by qRT‐PCR verification. More genes were observed to be overtranscribed in the highly resistant strain (91‐R) than in the moderately resistant strain (Wisconsin) and susceptible strain (Canton‐S). Furthermore, possible transcription factor binding sites that occurred in coexpressed resistance‐associated genes were discovered by computational motif discovery methods. Conclusion A glucocorticoid receptor (GR)‐like putative transcription factor binding motif (TFBM) was observed to be associated with genes commonly differentially transcribed in both the 91‐R and Wisconsin lines of DDT‐resistant Drosophila. © 2012 Society of Chemical Industry
  PubDate: 2013-02-01T07:14:56.217009-05:
  DOI: 10.1002/ps.3454
Effects of cyantraniliprole, a novel anthranilic diamide insecticide, against Asian citrus psyllid under laboratory and field conditions
- Authors: Siddharth Tiwari; Lukasz L Stelinski
  Pages: n/a - n/a
  Abstract: Background The Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae), is the most destructive pest of citrus in Florida. The development of insecticide resistance in several populations of D. citri has been documented. There is an urgent need to develop and integrate novel tools for the successful management of D. citri and also to prevent the development of insecticide resistance. Results The effects of a relatively newer chemistry, cyantraniliprole, against D. citri were investigated. The contact toxicity of cyantraniliprole was 297‐fold higher against D. citri than its primary parasitoid, Tamarixia radiata (Hymenoptera: Eulophidae). D. citri settled and fed less on cyantraniliprole‐treated plants than controls at concentrations as low as 0.025 and 0.125 µg AI mL−1 respectively. D. citri egg production, first‐instar emergence and adult emergence were significantly reduced on plants treated with 0.25, 0.02 and 0.25 µg AI mL−1 of cyantraniliprole, respectively, when compared with control plants. Under field conditions, foliar and drench treatments with cyantraniliprole (1436.08 g ha−1) reduced numbers of D. citri adults and nymphs, as well as of a secondary pest, citrus leafminer, Phyllocnistis citrella (Lepidoptera: Gracillariidae), more than a standard insecticide. Conclusions These results suggest that cyantraniliprole should be a valuable new tool for rotation into D. citri management programs. For insecticide resistance management, cyantraniliprole may be particularly useful for rotation with neonicotinoids. In addition, cyantraniliprole was much less toxic to T. radiata than to D. citri and thus may have less impact on biological control than other currently used broad‐spectrum insecticides, such as organophosphates and pyrethroids. © 2012 Society of Chemical Industry
  PubDate: 2013-02-01T07:14:47.854181-05:
  DOI: 10.1002/ps.3468
A single sex‐linked dominant gene does not fully explain the codling moth's resistance to granulovirus
- Authors: Marie Berling; Benoît Sauphanor, Antoine Bonhomme, Myriam Siegwart, Miguel Lopez‐Ferber
  Pages: n/a - n/a
  Abstract: Background In 2004, resistance to a commercial formulation of the Cydia pomonella granulovirus (CpGV) was identified in a field population of Cydia pomonella from an organic orchard in southern France. The genetic inheritance of this resistance was analyzed in the resistant laboratory strain RGV. This strain was obtained using successive crosses between the resistant field population and a susceptible laboratory strain, SV, with selection for CpGV resistance at each generation. Results After eight generations of introgression of the resistant trait into SV, the RGV‐8 strain exhibited 7,000‐fold higher resistance than SV. Mass‐crossing experiments showed that resistance to CpGV is strongly dominant, sex‐dependent and under the control of a single major gene. However, the contribution of other genes is required to explain all of the data obtained in this study. These additional genes do not follow the laws of classical Mendelian transmission. Conclusion Transmission of granulovirus resistance in the RGV‐8 strain of C. pomonella cannot be fully explained by the effect of a locus located on the Z chromosome. The action of other factors needs to be considered.
  PubDate: 2013-02-01T00:58:09.242315-05:
  DOI: 10.1002/ps.3493
A novel Cph‐like gene involved in histogenesis and maintenance of midgut in Bombyx mori
- Authors: Liping Gan; Weiwei Zhuo, Juan Li, Ying Wang, Yanghu Sima, Shiqing Xu
  Pages: n/a - n/a
  Abstract: Background Male‐biased silkworm larva resistance is useful for sericulture and lepidopteran pest control. According to previous research, the mechanism underlying this resistance might be related to midgut‐specific proteins. Results We cloned a midgut‐specific and novel hypothetical cuticular protein‐like (Cph‐like) gene based on sex‐disparity serial analysis of gene expression (SAGE) libraries of the B. mori midgut. The complete cDNA contained 676 bp and encoded 165 amino acid residues. The gene was located on chromosome 19 and it had only one short 75 bp intron. The Cph‐like expression level was downregulated by exogenous 20‐hydroxyecdysone or starvation, but up‐regulated by exogenous methoprene or food intake. Knockdown (siRNA) of the Cph‐like gene suppressed the appetite and delayed larval development, while it also degraded enterocytes and damaged the midgut morphology. Furthermore, the male‐biased cytoplasmic polyhedrosis virus (BmCPV) resistance of larvae was decreased. Conclusion Cph‐like is a midgut‐specific novel gene in B. mori that may participate in histogenesis and midgut maintenance.
  PubDate: 2013-01-29T07:05:24.148705-05:
  DOI: 10.1002/ps.3501
Electrophilic derivatives antagonize pheromone attraction in Cydia pomonella
- Authors: Albert Sans; Rafael Gago, Ares Mingot, Wanda García, Dolors Bosch, Josep Coll, Gloria Rosell, M. Pilar Bosch, Magí Riba, Angel Guerrero
  Pages: n/a - n/a
  Abstract: Background Pheromone antagonists are good disruptants of the pheromone communication in insects and, as such, have been used in mating disruption experiments. In this study, new non‐fluorinated electrophilic keto derivatives structurally related to the pheromone of Cydia pomonella (codlemone) have been synthesized and tested as putative pheromone antagonists. Results Codlemone (1) was prepared in excellent stereoselectivity in a new, iterative approach involving two Horner‐Wadsworth‐Emmons reactions. Methyl ketone 2, keto ester 3 and diketone 4 were obtained from codlemone in straightforward approaches in good overall yields and excellent stereochemical purity (≥98% E,E). In electrophysiology, only compound 2 displayed inhibition of the antennal response to the pheromone after presaturation of the antennal receptors. Compounds 2–4 did not inhibit the pheromone degrading enzyme responsible for codlemone metabolism but mixtures of ketone 2 and diketone 4 with codlemone elicited erratic flights on males in a wind tunnel. In the field, blends of either compound (2 or 4) with the pheromone caught significantly fewer males than codlemone alone. Conclusion Codlemone and the potential antagonists 2–4 have been synthesized in good yields and excellent stereoselectivity. These chemicals behave as pheromone antagonists of the codling moth both in the laboratory and in the field.
  PubDate: 2013-01-29T06:47:59.99369-05:0
  DOI: 10.1002/ps.3500
Molecular tools for sterile sperm detection to monitor Ceratitis capitata populations under SIT programmes
- Authors: María Juan‐Blasco; Beatriz Sabater‐Muñoz, Rafael Argilés, Josep A Jacas, Pedro Castañera, Alberto Urbaneja
  Pages: n/a - n/a
  Abstract: Background The success of an area‐wide sterile insect technique (SIT) programme against Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) relies on the mating success of sterile males in the field. Limited information is available about the effectiveness of sterile males in achieving mates with wild females and how these matings contribute to reducing wild populations. To this end, firstly a mating competition test was performed in the laboratory with different release ratios (1:1:0, 1:1:1, 1:1:5, 1:1:10 and 1:1:20 for wild females:wild males:sterile VIENNA‐8 males respectively) and different host fruit. Secondly, the same release ratios were evaluated under semi‐natural conditions on caged trees and on sentinel host. Results By means of molecular markers, VIENNA‐8 male sperm was positively detected in those females exposed to the male ratios 1:5, 1:10 and 1:20 in the laboratory. In the field test, sterile VIENNA‐8 male matings and the C. capitata progeny on apples were positively correlated with the ratio of sterile males released and with the percentage of sterile matings respectively. Conclusions These results confirm the validity of using the molecular detection of VIENNA‐8 male sperm to predict the C. capitata population under semi‐natural conditions. Implications of these results in measuring the efficacy of an SIT programme are discussed. © 2012 Society of Chemical Industry
  PubDate: 2013-01-28T05:11:07.600466-05:
  DOI: 10.1002/ps.3448
Assessing eradication strategies for rain‐splashed and wind‐dispersed crop diseases
- Authors: James C Bennett; Art Diggle, Fiona Evans, Michael Renton
  Pages: n/a - n/a
  Abstract: Background The eradicability of rain‐splashed crop diseases was examined by modelling the spread of lupin anthracnose over a spatially heterogeneous landscape. Two hypotheses were investigated: (i) in most cases, rain‐splashed diseases are unlikely to be eradicable because spread will be too extensive by the time the disease is detected; (ii) there are recognisable characteristics of an incursion that can be used to identify cases when the disease will be eradicable. Results Results indicate that the eradication of a rain‐splashed crop disease is heavily dependent on the surveillance effort, on how detectable the disease is and on whether there are susceptible hosts outside the cropping area. These simple indicators can be used to estimate the potential for success of an eradication scheme. Eradication targeting only the crop area is destined to fail, unless it is certain that no susceptible host lies adjacent to the cropping area. Conclusion A failed eradication attempt can be costly, and a simple set of indicators for the likelihood of success is extremely useful. These indicators can aid decision‐makers when faced with a new incursion, identifying when there is little hope of success. © 2012 Society of Chemical Industry
  PubDate: 2013-01-28T05:10:35.364141-05:
  DOI: 10.1002/ps.3459
Synthesis and antifeedant activity of novel alpha‐asarone derivatives against stored‐product pests
- Authors: Bożena Łozowicka; Piotr Kaczyński
  Pages: n/a - n/a
  Abstract: Background Alpha‐asarone (2,4,5‐trimethoxypropenylbenzene) derivatives represent a new series of compounds that possess good antifeedant activity against different stored‐product pests. Results A total of 23 novel alpha‐asarone derivatives were synthesised and identified by 1H NMR, 13C NMR and IR, and their feeding deterrent activities were tested against Sitophilus granarius L., Trogoderma granarium Ev. and Tribolium confusum Duv. Ten compounds showed strong antifeedant activities. Conclusion Some of the title compounds displayed very good and broad‐spectrum activities against adult and larval Coleoptera. The results indicate that the presence of a double bond in the side chain and three methoxy groups is important for antifeedant activity. © 2012 Society of Chemical Industry
  PubDate: 2013-01-28T05:10:29.591198-05:
  DOI: 10.1002/ps.3461
Solid lipid particles in lipid films to control the diffusive release of 2‐heptanone
- Authors: Cristina Bilbao‐Sáinz; Bor‐Sen Chiou, Greg M Glenn, Kay S Gregorsky, Tina G Williams, Delilah F Wood, Artur P Klamczynski, William J Orts
  Pages: n/a - n/a
  Abstract: Background Controlled‐release formulations of bioactive agents are of increasing interest for effective pest control. Volatile 2‐heptanone is a bioactive agent that has shown potential as a pesticide. The aim of this study was to investigate the kinetics of release of 2‐heptanone incorporated into lipid films or composite solid lipid particle (SLP) films. Results Effective 2‐heptanone diffusivity was estimated to be between 0.1 and 2.5 mm2 day−1 during the first week and between 0.05 and 0.1 mm2 day−1 during the next 5 weeks. The films that showed better retention of 2‐heptanone were the paraffin lipid films. Inclusion of SLPs into paraffin films increased the release rate of 2‐heptanone, mainly owing to a decrease in the film firmness as the composite SLP film became less crystalline and more brittle. In contrast, SLPs decreased the kinetics of 2‐heptanone release in Acetem films owing to an increase in the film firmness. Conclusions The results indicated that the use of SLPs as a method for controlled release can improve the delivery of the natural pesticide 2‐heptanone if the SLPs have good compatibility with the matrix, leading to an increase in firmness of the films without increasing their porosity. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.
  PubDate: 2013-01-28T05:09:44.91704-05:0
  DOI: 10.1002/ps.3462
Voltinism of Diabrotica speciosa (Coleoptera: Chrysomelidae) in Argentina: latitudinal clines and implications for damage anticipation
- Authors: G Cabrera Walsh; Joaquín Sacco, Federico Mattioli
  Pages: n/a - n/a
  Abstract: Background Diabrotica speciosa (Germar) is an important pest in South America. Both the adults and the larvae are polyphagous, and its most susceptible host is maize. Factors behind the appearance of adults in the field and geographical variations in voltinism are unknown. This hinders the chances of implementing rational control strategies. Results This study compiles field collection data from four agricultural regions of Argentina to examine the number of generations and phenology of D. speciosa in the field. This data is correlated to climatic data in order to provide evidence of regional variations and probable environmental causes for the appearance of adult generations in the field. Results indicate temperature has an important role in the appearance of new generations in the temperate distribution areas of D. speciosa, but not within its subtropical range, where teneral adults appeared all year round. Conclusion Results suggest emergence of adults may be elicited by weekly average temperatures above 13°C. In the temperate distribution areas of D. speciosa there could be at least three generations a year, and in the subtropical region at least five. No obvious or discrete voltinism pattern could be observed for D. speciosa in southern South America.
  PubDate: 2013-01-25T01:04:47.777437-05:
  DOI: 10.1002/ps.3498
Antagonistic bacteria Bacillus amyloliquefaciens induces resistance and controls the bacterial wilt of tomato
- Authors: Shiyong Tan; Yue Dong, Hanpeng Liao, Jianfeng Huang, Song Song, Yangchun Xu, Qirong Shen
  Pages: n/a - n/a
  Abstract: Background Bacterial wilt caused by Ralstonia solanacearum (RS) is a serious threat for agricultural production. In this study, we used Bacillus amyloliquefaciens strains CM‐2 and T‐5 antagonistic to RS to create bioorganic fertilizers to control the tomato wilt under greenhouse conditions. The possible mechanism of inducing resistance by the antagonistic bacteria was also evaluated. Results The application of bioorganic fertilizers significantly reduced the incidences of tomato wilt (63‐74%), promoted the plant growth, and significantly reduced the RS populations in rhizosphere compared to the control. Both strains CM‐2 and T‐5 applied with bioorganic fertilizers survived well in the tomato rhizosphere. Tomato seedlings treated with cell suspension of T‐5 followed by challenge inoculation with RS increased the activities of polyphenol oxidase, phenylalanine ammonia lyase, and peroxidase compared to the untreated control. Furthermore, the expressions of the marker genes responsible for synthesis of phytohormones salicylic acid, ethylene and jasmonic acid in seedlings treated with T‐5 in response to inoculated pathogen were significantly higher. Conclusions This study suggests that strains CM‐2 and T‐5 containing bioorganic fertilizers effectively control the tomato wilt. Increased enzyme activities and expression of defense genes in plants indicated that the antagonistic bacteria induced the plant resistance, which was the potential biocontrol mechanism of tomato wilt.
  PubDate: 2013-01-21T15:55:22.560583-05:
  DOI: 10.1002/ps.3491
Does insecticide application in a winter oilseed rape field influence the abundance of pollen beetle Meligethes aeneus in nearby ornamental flowers and vegetables'
- Authors: Nur Ahmed; Jan‐Eric Englund, Eva Johansson, Inger Åhman
  Pages: n/a - n/a
  Abstract: Background Pollen beetle is a pest that attacks oilseed rape as well as many other brassicaceous crops, garden vegetables and ornamental flowers. The present study was primarily carried out to investigate whether insecticide application in brassicaceous field crops might influence the abundance of pollen beetles in nearby private garden flowers and vegetables. Results In peak emergence of the new generation of pollen beetles, a significantly higher number of beetles were found in flowers, and in window traps, alongside the untreated as compared to alongside the treated sections of the winter oilseed rape (WOSR) field. However, the type of flower played a role for the number of pollen beetles found in the flowers. The presence of pollen beetles in both ornamental and wild flowers was also significantly influenced by the direction of the placement of the flowers. No pollen beetle, neither over‐wintering nor newly emerged, was observed in any of the brassicaceous vegetables placed along the field. Conclusion The amount of pollen beetles in the WOSR field strongly influenced the amount of pollen beetles in nearby flowers of preference to the beetles, and insecticide treatment with Biscaya (thiacloprid) against pollen beetle in oilseed rape may thus help, indirectly, to protect nearby garden flowers from damage.
  PubDate: 2013-01-21T14:15:53.165397-05:
  DOI: 10.1002/ps.3492
Larvicidal Activities and Chemical Composition of Essential Oils from Piper klotzschianum (Kunth) C.DC. (Piperaceae)
- Authors: Jeferson C do Nascimento; Jorge M David, Luiz CA Barbosa, Vanderlucia F Paula, Antonio J. Demuner, Juceni P David, Lucia M Conserva, Jésu C Ferreira‐, Elsie F Guimarães
  Pages: n/a - n/a
  Abstract: Background Volatile oils from fresh roots, stems, leaves and seeds of Piper klotzschianum (Piperaceae) were obtained by hydrodistillation and analyzed by GC‐FID and GC‐MS. In total, 25 components, representing more than 95% of the examined oils, were identified. The essential oils were evaluated against Artemia salina Leach nauplii and fourth instar Aedes aegypti larvae. Results The major chemical constituents that were identified from various parts of this plant were 1‐butyl‐3,4‐methylenedioxybenzene and 2,4,5‐trimethoxy‐1‐propenylbenzene in the root, 1‐butyl‐3,4‐methylenedioxybenzene in its stems and leaves, and 1‐butyl‐3,4‐methylenedioxybenzene, limonene and α‐phellandrene in its seeds. The biological activities of these essential oils generally exhibited high toxicity against A. salina, with LC50 values that ranged from 7.06 to 15.43 µg mL‐1, and significant larvicidal activity against fourth instar A. aegypti larvae was observed in the essential oils from the seeds (LC50 of 13.27 µg mL‐1) and roots (LC50 of 10.0 µg mL‐1) of the plant. Conclusion The present study indicates both essential oil of P. klotzsdhianum and the isolate 1‐butyl‐3,4‐methylenedioxybenzene are potential resources for A. aegypti larvae control. This is the first report of the biological activities of the oil and isolated compound.
  PubDate: 2013-01-21T13:05:42.764052-05:
  DOI: 10.1002/ps.3495
Soil residue analysis and degradation of saflufenacil as affected by moisture content and soil characteristics‡
- Authors: Edinalvo R Camargo; Scott A Senseman, Richard L Haney, John B Guice, Garry N McCauley
  Pages: n/a - n/a
  Abstract: Background Saflufenacil dissipation in soils under different moisture conditions is not available in the scientific literature. The objective of this study was to evaluate saflufenacil degradation and persistence in soils from rice regions under field capacity (non‐flooded) and saturated (flooded) conditions. Results The accelerated solvent extraction (ASE) residue analytical method developed to conduct the study resulted in recovery greater than 80% for the combinations of soils and moisture conditions. Saflufenacil degradation was faster at field capacity for all soils, except for Morey soil. Herbicide half‐life was 28.6, 15.0, and 23.1 days under field capacity treatments and 58.8, 36.9 and 79.7 under saturated conditions for Nada, Crowley, and Gilbert soils, respectively. Half‐life no longer than 80 days was observed for the combination of soils and moisture treatments. Conclusion An ASE method was developed and used to extract saflufenacil from soil samples. Half‐life averaged among soils was 59 and 33 days for saturated and field capacity, respectively. Saflufenacil persistence in the environment was 2 to 3 times longer under flooded conditions for most of the soils studied.
  PubDate: 2013-01-21T13:01:52.025011-05:
  DOI: 10.1002/ps.3494
Degradation and mineralisation of diuron by Sphingomonas sp. SRS2 and its potential for remediating at a realistic µg L‐1 diuron concentration
- Authors: Sebastian R. Sørensen; René K. Juhler, Jens Aamand
  Pages: n/a - n/a
  Abstract: Background Low concentrations (10‐6 – 10‐9 g L‐1) of the herbicide diuron are occasionally detected as water contaminants in areas around the world where the herbicide is used extensively. Remediation of contaminated waters using diuron‐mineralising bacteria is a possible approach for cleaning these resources. However few diuron‐mineralising strains have been isolated. Here we test the ability of Sphingomonas sp. SRS2, a well‐known soil bacterium capable of degrading the structurally related herbicide isoproturon, to mineralise diuron at realistically low concentrations. Results Strain SRS2 readily degraded the dimethylurea side‐chain, while no or only slow mineralisation of the ring structure was determined. By monitoring metabolites, we determined that SRS2 initially degraded diuron by two successive N‐demethylations followed by cleavage of the urea‐group to 3,4‐dichloro‐aniline (3,4‐DCA). Mineralisation of low diuron concentrations by SRS2 was detected and could be stimulated by addition of a complex nutrient source. Further enhancement of the mineralisation activity was obtained by combining SRS2 with the 3,4‐DCA‐mineralising Variovorax sp. SRS16. Conclusion This work demonstrates that Sphingomonas sp. SRS2 is a promising candidate for bioaugmentation, alone or in combination with other strains, and that enhanced diuron mineralisation at realistically low concentrations can be achieved.
  PubDate: 2013-01-21T12:59:27.001895-05:
  DOI: 10.1002/ps.3490
Structure‐activity relationships of monoterpenes and acetyl derivatives against Aedes aegypti (Diptera: Culicidae) larvae
- Authors: Satish K Pandey; Sudeep Tandon, Ateeque Ahmad, Anil K Singh, Arun K Tripathi
  Pages: n/a - n/a
  Abstract: Background Dengue fever virus transmitted by Aedes aegypti causes lethal mortalities of human beings and due to lack of any vaccine, management of this vector especially with phytochemicals is essential. In the present investigation structure‐activity relationship of monoterpenes and their acetyl derivatives was studied to identify structural features that are responsible for mosquitocidal activity. Results Derivatization of monoterpenes (eugenol, geraniol, linalool, l‐menthol and terpeniole) followed by structure‐activity relationship studies identified that all the five acetyl derivatives with enhanced mosquitocidal activity against 4th instar larvae of Aedes aegypti. Acetylation of hydroxyl group in general have increased the activity as compared to their hydroxyl compounds. Based on LC50 values (ppm), the activities were in order of eugenyl acetate (50.2) > linalyl acetate (119.7) > terpinyl acetate (287.1) > menthyl acetate (308.4) > geranyl acetate (325.5) as compared to monoterpemoids, eugenol (82.8) > linalool (242.6) > terpineol (331.7) > l‐menthol (365.8) > geraniol (415.0). In eugenyl acetate, presence of aromatic ring and a side chain with allylic double bond makes it most effective. Conclusion Bioactive functional groups identified in the study may contribute to the understanding of larvicidal activity of acetyl derivatives and may help in development of eco‐friendly mosquito larvicidal compounds.
  PubDate: 2013-01-21T12:58:36.953458-05:
  DOI: 10.1002/ps.3488
Effect of trehalose on the biocontrol efficacy of Pichia caribbica against post‐harvest grey mould and blue mould decay of apples
- Authors: Lina Zhao; Hongyin Zhang, Hetong Lin, Xiaoyun Zhang, Xiaofeng Ren
  Pages: n/a - n/a
  Abstract: Background The influence of adding trehalose to the culture medium on the efficacy of Pichia caribbica (JSU‐1) in controlling post‐harvest grey mould and blue mould decay of apples and the possible mechanisms involved were investigated. Results The antagonistic activity of P. caribbica harvested from nutrient yeast dextrose broth (NYDB) amended with trehalose at 5 mg mL−1 to post‐harvest grey mould and blue mould decay was improved greatly compared with that without trehalose. The intracellular trehalose content of P. caribbica harvested from NYDB amended with trehalose at 5 mg mL−1 was higher than that of P. caribbica harvested from NYDB. The population of P. caribbica could rapidly colonise and grow in apple wounds. Moreover, the application of P. caribbica cultivated in the culture medium of the trehalose supplement (5 mg mL−1) induced higher polyphenoloxidase (PPO) and peroxidase (POD) activity of apples compared with that cultivated by P. caribbica in the NYDB. SEM results suggested that P. caribbica harvested from NYDB amended with trehalose at 5 mg mL−1 showed stronger inhibition efficacy to Botrytis cinerea than P. caribbica harvested from NYDB. Conclusion The antagonistic activity of P. caribbica can be enhanced by adding trehalose to the medium. © 2012 Society of Chemical Industry
  PubDate: 2013-01-16T11:15:27.100188-05:
  DOI: 10.1002/ps.3463
A Quantitative Analysis of a Modified Feeding Method for Rearing Cimex lectularius (Hemiptera: Cimicidae) in the Laboratory
- Authors: Eva Chin‐Heady; Joseph J DeMark, Steve Nolting, Gary Bennett, Kurt Saltzmann, Ronda L Hamm
  Pages: n/a - n/a
  Abstract: BACKGROUND: A modified artificial feeding system was developed for rearing Cimex lectularius and compared to the most widely used artificial feeding method that requires custom made glassware and a circulating water bath to warm the blood. The Petri dish method reduces some of the drawbacks from the current water bath method, such as the possibility of flooding bed bug rearing jars with either water or blood and the need for expensive custom made glassware. RESULTS: Field and lab strain first instar nymphs were given a 15 or 30 minutes interval to feed for 6‐9 weeks. Analysis of bed bugs that fed during a six week time period showed that there were no significant different in the numbers that fed using the Petri method compared to those that fed using the water bath method. Development of the nymphs also showed that there were no significant differences for the time it took to produce adults from either method. CONCLUSION: The Petri dish method is an attractive alternative compared to the water bath method, set up is less complex and quicker, multiple jars of bed bugs can be fed at the same time, Petri dishes of blood are disposable for easy clean up, and the potential of fatality due to flooding with blood or water is reduced. Copyright © 2012 Society of Chemical Industry
  PubDate: 2013-01-07T10:52:46.996187-05:
  DOI: 10.1002/ps.3482
Dosage consistency is the key factor in avoiding evolution of resistance to phosphine and population increase in stored‐grain pests
- Authors: Mingren Shi; Patrick J Collins, T James Ridsdill‐Smith, Robert N Emery, Michael Renton
  Pages: n/a - n/a
  Abstract: BACKGROUND Control of pests in stored grain and the evolution of resistance to pesticides are serious problems worldwide. A stochastic individual‐based two‐locus model was used to investigate the impact of two important issues, the consistency of pesticide dosage through the storage facility and the immigration rate of the adult pest, on overall population control and avoidance of evolution of resistance to the fumigant phosphine in an important pest of stored grain, the lesser grain borer. RESULTS A very consistent dosage maintained good control for all immigration rates, while an inconsistent dosage failed to maintain control in all cases. At intermediate dosage consistency, immigration rate became a critical factor in whether control was maintained or resistance emerged. CONCLUSION Achieving a consistent fumigant dosage is a key factor in avoiding evolution of resistance to phosphine and maintaining control of populations of stored‐grain pests; when the dosage achieved is very inconsistent, there is likely to be a problem regardless of immigration rate. © 2012 Society of Chemical Industry
  PubDate: 2013-01-03T11:28:35.270707-05:
  DOI: 10.1002/ps.3457
Evidence of superclones in Australian cotton aphid Aphis gossypii Glover (Aphididae: Hemiptera)
- Authors: Yizhou Chen; Flavie Vanlerberghe‐Masutti, Lewis J Wilson, Idris Barchia, Martin O McLoon, Tanya Smith, Grant A Herron
  Pages: n/a - n/a
  Abstract: Background Aphis gossypii is an important pest of cotton that has developed resistance to many chemicals used for its control. Any lack of understanding of its genetic structure, resistance status and host plant specialisation hampers effective management. Rsults Eight microsatellite markers were genotyped for a collection of Australian A. gossypii field isolates from 55 plant species from major Australian cotton‐producing regions. The aphid's pirimicarb resistance status linked to the ACE1 (acetylcholinesterase) S431F mutation was determined by PCR‐RFLP. Overall, the genetic diversity was low and there were only 13 multilocus genotype (MLG) groups found in a total of 936 aphids, suggesting asexual reproduction. Three MLGs (Aust‐01, Aust‐02 and Aust‐04) represented 78% of all aphids tested. MLGs Aust‐01 (41%) and Aust‐02 (18%) were linked to the ACE1 S431F mutation and found on cotton and a range of hosts. Aust‐04 (19%) hosted mainly on cotton (but also Asteraceae and Malvaceae) was predominantly susceptible to pirimicarb. Given their abundance and widespread occurrence, these three clones were considered to be superclones. Conclusion The study demonstrated that any strategy to control A. gossypii and manage pirimicarb resistance should target A. gossypii strains of all MLG types residing on any plant species and not just cotton.© 2012 Society of Chemical Industry
  PubDate: 2013-01-03T11:27:03.801237-05:
  DOI: 10.1002/ps.3455
Attract‐and‐kill: A new strategy for the management of the potato tuber moths Phthorimaea operculella (Zeller) and Symmetrischema tangolias (Gyen) in potato: Evaluation of its efficacy under potato field and storage conditions
- Authors: Jürgen Kroschel; Octavio Zegarra
  Pages: n/a - n/a
  Abstract: BACKGROUND: Attract‐and‐kill composed of pure sex pheromones of the potato tuber moths Phthorimaea operculella (Zeller) and Symmetrischema tangolias (Gyen) and the insecticide cyfluthrin resulted in 100% mortality of males under controlled laboratory conditions. The aim of the present study was to investigate the efficacy of this strategy in different potato agroecologies as well as under simulated potato storage conditions. RESULTS: Attract‐and‐kill was highly effective at reducing male flight activity and significantly reduced daily moth catches between 51.8% and 99.9% in pheromone‐baited water traps compared to untreated plots. This largely depended on the field size, the attract‐and‐kill droplet size and density applied per hectare. Highest efficacy, which was independent of pest density, was achieved when attract‐and‐kill was applied on larger potato fields using a droplet density of 2500 source points/ha at a droplet size of 100 µl. Consequently, pest infestation on vegetative plant parts as well as on tubers was significantly reduced up to 90% compared to untreated controls. Under simulated storage conditions with a high number of females and males released periodically, an efficacy of 84.1% and 87.2% was achieved to reduce tuber infestation by P. operculella and S. tangolias, respectively. CONCLUSIONS: Attract‐and‐kill is very effective to control the two potato tuber moth species under both field and storage conditions; it is a new attractive and for storage conditions a low‐cost method that can be easily integrated in potato pest management programs, especially of small‐scale agricultural systems of the tropics and subtropics. Copyright © 2012 Society of Chemical Industry
  PubDate: 2013-01-03T11:18:59.45951-05:0
  DOI: 10.1002/ps.3483
Influence of soil environments on nematicidal activity of fluensulfone against Meloidogyne javanica
- Authors: Yuji Oka; Shimshon Shuker, Nadia Tkachi
  Pages: n/a - n/a
  Abstract: BACKGROUND: Fluensulfone, a fluoroalkenyl group nematicide, has proven to be very effective in controlling root‐knot nematodes, Meloidogyne spp. We evaluated some soil environmental factors that might affect its nematicidal activity. RESULTS: Meloidogyne javanica juveniles exposed to fluensulfone lost their infectivity, even though they were rinsed in water when they were still active. Exposure of juveniles to fluensulfone at >1 mg L–1 for 48 h was very effective in reducing root galls. Peat as organic matter added to soil reduced nematicidal efficacy against M. javanica in pot experiments. Peat added to a soil column inhibited the downward movement of fluensulfone. The movement of fluensulfone was faster in sandy vs. loess soil. Repeated soil application of fluensulfone did not reduce the nematicidal activity of fenamiphos or cadusafos, and repeated applications of these nematicides did not lower the nematicidal activity of a subsequent application of fluensulfone. CONCLUSION: Fluensulfone nematicidal activity and movement were affected by organic matter and clay content, probably via adsorption. Enhanced biodegradation or cross‐biodegradation of fluensulfone by other compounds was not observed. Soil environment should be considered to obtain effective nematode control efficacy with a given compound. Copyright © 2012 Society of Chemical Industry
  PubDate: 2013-01-03T11:18:34.909867-05:
  DOI: 10.1002/ps.3487
Translocation and degradation of tebuconazole and prothioconazole in wheat following fungicide treatment at flowering
- Authors: Szabolcs Lehoczki‐Krsjak; Mónika Varga, Ágnes Szabó‐Hevér, Ákos Mesterházy
  Pages: n/a - n/a
  Abstract: BACKGROUND Prothioconazole and tebuconazole are among the most effective fungicides against Fusarium head blight (FHB) of wheat (Triticum aestivum L.). The translocation between the ears and the flag leaves and the kinetics of degradation may influence field efficacy of these active ingredients (a.i.‐s). RESULTS In greenhouse experiments, only traces (
  PubDate: 2013-01-03T11:18:21.938389-05:
  DOI: 10.1002/ps.3486
Occurrence and larval movement of Diatraea saccharalis (Lepidoptera: Crambidae) in seed mixes of non‐Bt and Btpyramid corn
- Authors: David S. Wangila; B. Rogers Leonard, Mukti N. Ghimire, Yaoyu Bai, Liping Zhang, Yunlong Yang, Karla D. Emfinger, Graham P. Head, Fei Yang, Ying Niu, Fangneng Huang
  Pages: n/a - n/a
  Abstract: BACKGROUND: Larval movement of target pest populations among Bt and non‐Bt plants is a major concern in the use of a seed mixture refuge strategy for Bt resistance management. In this study, occurrence and larval movement of the sugarcane borer, Diatraea saccharalis (F.), were evaluated in four planting patterns of non‐Bt and Bt plants containing Genuity®SmartStaxTM traits in 2009‐2011. The four planting patterns were: 1) a pure stand of 27 Bt plants; 2) one non‐Bt plant in the center surrounded by 26 Bt plants, 3) a pure stand of 27 non‐Bt plants, and 4) one Bt plant in the center surrounded by 26 non‐Bt plants. Studies were conducted underfour conditions: (1) open field with natural infestation; (2) greenhousewith artificial infestations; and open field with artificial infestations (3) on the center plants only and (4) on every plant. The major objective of this study was to determine if refuge plants in a seed mixture strategy could provide a comparable refuge population of D. saccharalis toa “structured refuge” planting. RESULTS: Larvae of D. saccharalis showed the ability to move from infested plants to at least four plants away as well as to adjacent rows but the majority remained within the infested row. However, the number of larvae found on the non‐Bt plants in the mixture plantings was not significantly reduced compared to the pure stand of non‐Bt corn. CONCLUSION: The results of this study show that refuge plants in a seed mixture may be able to provide a comparable refuge population of D. saccharalisto a “structured refuge” planting. Copyright © 2012 Society of Chemical Industry
  PubDate: 2013-01-03T11:15:13.789447-05:
  DOI: 10.1002/ps.3484
In‐vitro antifungal activity of synthetic dsRNA molecules against two pathogens of banana, Fusarium oxysporum f.sp. cubense and Mycosphaerella fijiensis
- Authors: Francis M. Mumbanza; Andrew Kiggundu, Geoffrey Tusiime, Wilberforce K. Tushemereirwe, Chuck Niblett, Anna Bailey
  Pages: n/a - n/a
  Abstract: BACKGROUND: A key challenge for designing RNAi‐based crop‐protection strategies is the identification of effective target genes in the pathogenic organism. In this study, in‐vitro antifungal activities of a set of synthetic double‐stranded RNA molecules on spore germination of two major pathogenic fungi of banana, Fusarium oxysporum Schlecht f.sp. cubense WC snyder & HN Hans (Foc) and Mycosphaerella fijiensis Morelet (Mf) were evaluated. RESULTS: All the tested synthetic dsRNAs successfully triggered the silencing of target genes and displayed varying degrees of potential to inhibit spore germination of both tested banana pathogens. When Foc dsRNAs were applied to Foc spores, inhibition ranged from 79.8 to 93.0 % and 19.9 to 57.8 % when Foc dsRNAs were applied to Mf spores. However, when Mf dsRNAs were applied on Mf spores, inhibition ranged from 34.4 to 72.3 % and 89.7 to 95.9 % when Mf dsRNA were applied to Foc spores. CONCLUSION: The dsRNAs for adenylate cyclase, DNA polymerase alpha subunit and DNA polymerase delta subunit showed high levels of spore germination inhibition during both self and cross species tests, making them the most promising targets for RNA‐mediated resistance in banana against these fungal pathogens. Copyright © 2012 Society of Chemical Industry
  PubDate: 2013-01-03T11:14:55.944464-05:
  DOI: 10.1002/ps.3480
Insecticidal effect of chlorantraniliprole against major stored product insect pests in different grain commodities under laboratory tests
- Authors: Nickolas G Kavallieratos; Christos G Athanassiou, Maria C Boukouvala
  Pages: n/a - n/a
  Abstract: BACKGROUND: Chlorantraniliprole belongs to the chemical group of anthranilic diamides. It has selectivity to beneficial arthropods and low mammalian toxicity. Laboratory bioassays were conducted to assess chlorantraniliprole as a potential grain protectant against Ephestia kuehniella Zeller larvae, Liposcelis bostrychophila Badonnel adults, Rhyzopertha dominica (F.) adults, Sitophilus oryzae (L.) adults and Tribolium confusum Jacquelin du Val adults and larvae. Factors such as dose (0.01, 0.1, 1 and 10 mg chlorantraniliprole kg‐1 grain), exposure interval (7 days and 14 days), formulation (chlorantraniliprole WG and chlorantraniliprole SC) and commodity (barley, maize, oats, peeled rice, whole rice and wheat) were evaluated upon their impact on the insecticidal activity of chlorantraniliprole. Progeny production was assessed after 45 days of exposure in the case of L. bostrychophila adults and 60 days of exposure in the case of R. dominica, S. oryzae and T. confusum adults. RESULTS: For L. bostrychophila adults, after 7 days of exposure mortality was lower in maize and whole rice in comparison to the other commodities. The increase of dose generally increased mortality. Similar trends were also noted after 14 days of exposure. Offspring emergence was higher in maize and whole rice in comparison to the other commodities. For E. kuehniella larvae, after 7 days of exposure significant differences were noted among the tested commodities. The increase of dose only slightly increased mortality in all commodities. After 14 days of exposure mortality was further increased, but did not reach 100%. For R. dominica adults, after 7 days of exposure the increase of dose increased mortality significantly. After 14 days of exposure, mortality in barley, maize, whole rice and wheat exceeded 92% at 10 mg chlorantraniliprole kg‐1 grain. Offspring emergence was decreased, but it was not achieved 100% progeny suppression. For S. oryzae adults, after 7 days of exposure mortality was generally low at dose rates ≤ 1 mg chlorantraniliprole kg‐1 grain. After 14 days of exposure, 100% mortality was noted in whole rice. For T. confusum adults, after 7 days of exposure mortality was low. After 14 days of exposure mortality increased proportionately for all commodities. Most progeny production was noted in oats. For T. confusum larvae, after 7 days of exposure, mortality was generally higher in comparison to adults. After 14 days of exposure, mortality in maize was high. Generally, both formulations performed alike for all the tested insects. CONCLUSIONS: Based on the results of the present work, chlorantraniliprole is effective against major stored product insect species. However, efficacy depends upon the type of the commodity, the dose rate and the exposure interval. Copyright © 2012 Society of Chemical Industry
  PubDate: 2013-01-03T11:14:11.96535-05:0
  DOI: 10.1002/ps.3478
Different toxic and hormetic responses of Bombus impatiens to Beauveria bassiana, Bacillus subtilis and spirotetramat
- Authors: Krilen Ramanaidu; G Christopher Cutler
  Pages: n/a - n/a
  Abstract: BACKGROUND Pollinator exposure to pesticides is a concern in agricultural systems that depend on pollinators for crop production. However, not all pesticides elicit toxic effects, and response to a pesticide will vary depending on dose and exposure route. The effects of biopesticide formulations of Bacillus subtilis and Beauveria bassiana and of the tetramic acid insecticide spirotetramat on the common eastern bumblebee, Bombus impatiens, were evaluated. Microcolonies of bees were exposed to field‐rate or lower concentrations, and data were collected over 60 days. RESULTS When ingested, field rates of spirotetramat caused high mortality after 10 days, and B. subtilis significantly reduced drone production, number of days to oviposition and number of days to drone emergence. Converse to effects observed following ingestion, topical applications of B. subtilis at concentrations less than the recommended field rate resulted in a hormetic response, with significantly increased drone production. Topical application of spirotetramat and oral or topical application of B. bassiana had no effects on bees. CONCLUSIONS Spirotetramat and B. subtilis can induce adverse effects on B. impatiens, but hormetic effects following B. subtilis treatment can also occur, depending on exposure route. Additional experiments are required to determine whether similar toxic or hormetic effects occur under more realistic field conditions. © 2012 Society of Chemical Industry
  PubDate: 2012-12-24T08:34:56.905268-05:
  DOI: 10.1002/ps.3456
Modelling pesticide sorption in the surface and subsurface soils of an agricultural catchment
- Authors: Abdul Ghafoor; Nicholas J. Jarvis, John Stenström
  Pages: n/a - n/a
  Abstract: BACKGROUND Sorption models that improve upon the koc concept are urgently needed for reliable spatial modelling of pesticide leaching. Sorption of glyphosate, bentazone and isoproturon was measured in surface and subsurface soils to test an ‘extended’ partitioning model that also accounts for inorganic sorbents and pH. Best‐subset regression and Akaike information criteria were used to justify the inclusion of predictors and identify suitable models. RESULTS The extended partitioning model improved upon the koc concept for all three compounds: inorganic sorbents dominated sorption in subsurface soils, and their effects were only masked by organic matter in surface soils with organic carbon contents larger than ca 2%. Interactions between organic and inorganic sorbents affected glyphosate sorption, but apparently not that of bentazone or isoproturon. CONCLUSION Information on clay, iron and aluminium oxides and soil pH, in addition to organic carbon, is needed for accurate prediction of pesticide leaching. The variables foc, fclay and pH are generally available, whereas measurements of oxides of Al and Fe are rarely reported. The authors therefore emphasise the need to measure and report contents of oxides of Al and Fe in soil survey databases, because small variations in their concentrations may contribute significantly to large variations in sorption, especially of ionisable pesticides. © 2012 Society of Chemical Industry
  PubDate: 2012-12-21T04:28:35.274164-05:
  DOI: 10.1002/ps.3453
The phenolic monoterpenoid carvacrol inhibits the binding of nicotine to the housefly nicotinic acetylcholine receptor
- Authors: Fan Tong; Aaron D Gross, Marc C Dolan, Joel R Coats
  Pages: n/a - n/a
  Abstract: Background The phenolic monoterpenoid carvacrol, which is found in many plant essential oils (thyme, oregano and Alaska yellow cedar), is highly active against pest arthropods, but its mechanisms of action are not fully understood. Here, carvacrol is shown to bind in a membrane preparation containing insect nicotinic acetylcholine receptors (nAChRs). [14C]‐Nicotine binding assays with Musca domestica (housefly) nAChRs were used in this study to demonstrate carvacrol's binding to nAChRs, thereby acting as a modulator of the receptors. Results Carvacrol showed a concentration‐dependent inhibition of [14C]‐nicotine binding in a membrane preparation of housefly heads containing nAChRs, with IC50 = 1.4 μM, in a non‐competitive pattern. Binding studies with neonicotinoid insecticides revealed that imidacloprid and thiamethoxam did not inhibit the binding of [14C]‐nicotine, while dinotefuran, from the guanidine subclass of neonicotinoids, inhibited nicotine binding like carvacrol. Conclusions Carvacrol binds to housefly nAChRs at a binding site distinct from nicotine and acetylcholine, and the nAChRs are a possible target of carvacrol for its insecticidal activity.© 2012 Society of Chemical Industry
  PubDate: 2012-12-18T06:26:25.827537-05:
  DOI: 10.1002/ps.3443
Selection of a fungal isolate for the control of the pink hibiscus mealybug Maconellicoccus hirsutus
- Authors: Karla H Ibarra‐Cortés; Ariel W Guzmán‐Franco, Héctor González‐Hernández, Javier Suarez‐Espinosa, Jason Baverstock
  Pages: n/a - n/a
  Abstract: Background Maconellicoccus hirsutus Green is a widely distributed pest of numerous crops. Although synthetic pesticides are used to control this pest, entomopathogenic fungi may provide an alternative control mechanism. Three experiments were carried out to select a fungal isolate with the potential to be used as a microbial control agent. The in vitro growth of five isolates of Beauveria bassiana sensu lato (Bals.) Vuill and Metarhizium anisopliae sensu lato (Metschn.) Sorokín, along with three isolates of Lecanicillium lecanii (Zimm.) Zare & W. Gams and Isaria fumosoroseus (Wize), was assessed at four temperatures. The in vivo sporulation of eight selected isolates was then evaluated, followed by the susceptibility of third‐instar M. hirsutus to a single dose (1 × 108 conidia mL−1) of each of these isolates. Results Growth was greatest by isolates of I. fumosoroseus and L. lecanii at 15 and 20 °C and by isolates of M. anisopliae at 25 and 30 °C. In vivo conidium production was greatest when infected with B. bassiana isolate GHA and M. anisopliae isolate Ma65. Mortality was greatest when inoculated with M. anisopliae isolates Ma65 and Ma129. Conclusion Isolate Ma65 shows the best potential to be developed as a microbial control agent for M. hirsutus.© 2012 Society of Chemical Industry
  PubDate: 2012-12-18T06:26:21.67748-05:0
  DOI: 10.1002/ps.3452
Efficacy of the African weaver ant Oecophylla longinoda (Hymenoptera: Formicidae) in the control of Helopeltis spp. (Hemiptera: Miridae) and Pseudotheraptus wayi (Hemiptera: Coreidae) in cashew crop in Tanzania
- Authors: Moses I Olotu; Hannalene Plessis, Zuberi S Seguni, Nguya K Maniania
  Pages: n/a - n/a
  Abstract: BACKGROUND Cashew, Anacardium occidentale, is an economically important cash crop for more than 300 000 rural households in Tanzania. Its production is, however, severely constrained by infestation by sap‐sucking insects such as Helopeltis anacardii, H. schoutedeni and Pseudotheraptus wayi. The African weaver ant, Oecophylla longinoda, is an effective biocontrol agent of hemipteran pests in coconuts in Tanzania, but its efficacy in the control of Helopeltis spp. and P. wayi in Tanzanian cashew has not been investigated so far. The aim of this study was therefore to evaluate the efficacy of O. longinoda in the management of these insect pests in the cashew crop at different sites of the Coast region of Tanzania. RESULTS Colonisation levels of O. longinoda, expressed as weaver ant trails, varied from 57.1 to 60.6% and from 58.3 to 67.5% in 2010 and 2011 respectively. The mean number of leaf nests per tree varied from five to eight nests in 2010 and from five to nine nests in 2011. There was a negative correlation between numbers of nests and pest damage. Oecophylla longinoda‐colonised cashew trees had the lowest shoot damage by Helopeltis spp. of 4.8 and 7.5% in 2010 and 2011, respectively, as opposed to uncolonised cashew trees with 36 and 30% in 2010 and 2011 respectively. Similarly, nut damage by P. wayi was lowest in O. longinoda‐colonised trees, with only 2.4 and 6.2% in 2010 and 2011 as opposed to uncolonised trees with 26 and 21%. CONCLUSION Oecophylla longinoda is an effective biocontrol agent of the sap‐sucking pests of cashew in the Coast region of Tanzania and should be considered as an important component of IPM. © 2012 Society of Chemical Industry
  PubDate: 2012-12-12T15:21:15.571761-05:
  DOI: 10.1002/ps.3451
Target‐site mutation associated with cross‐resistance to ALS‐inhibiting herbicides in late watergrass (Echinochloa oryzicola Vasing.)
- Authors: Nikolaos S Kaloumenos; Sofia L Chatzilazaridou, Photini V Mylona, Alexios N Polidoros, Ilias G Eleftherohorinos
  Pages: n/a - n/a
  Abstract: BACKGROUND Studies were carried out to elucidate the mechanism of resistance to ALS‐inhibiting herbicides in 29 Echinochloa accessions from water‐seeded rice fields of northern Greece and to discriminate the Echinochloa species. RESULTS Two E. oryzicola accessions were found to be cross‐resistant to penoxsulam, bispyribac‐sodium, imazamox, foramsulfuron, nicosulfuron and rimsulfuron, whereas all accessions were susceptible (S) to profoxydim. Sequencing of the ALS gene revealed that resistant (R) accessions had a Trp574Leu mutation, which was also confirmed by TspRI endonuclease digestion. Use of cpDNA sequence comparison analysis of Echinochloa species discriminated successfully E. crus‐galli and E. oryzicola accessions. CONCLUSION This is the first report of Echinochloa oryzicola cross‐resistance to ALS‐inhibiting herbicides as a result of Trp574Leu mutation. The cpDNA sequence comparison analysis is a reliable tool for discrimination of conventionally classified E. crus‐galli and E. oryzicola accessions. © 2012 Society of Chemical Industry
  PubDate: 2012-12-06T14:39:55.904199-05:
  DOI: 10.1002/ps.3450
A new dibenzoylhydrazine with insecticidal activity against Anopheles mosquito larvae
- Authors: Evangelia Morou; Manolis Lirakis, Nena Pavlidi, Moises Zotti, Yoshiaki Nakagawa, Guy Smagghe, John Vontas, Luc Swevers
  Pages: n/a - n/a
  Abstract: BACKGROUND Dibenzoylhydrazine (DBH) compounds have been applied successfully as environmentally safe insecticides against lepidopteran larvae and ground‐dwelling coleopterans, but their potential to combat mosquito larvae is largely unknown. Here, toxicity tests of three commercial DBHs (tebufenozide, methoxyfenozide and halofenozide) and one experimental DBH (KU‐106) against larvae of Anopheles gambiae, the major vector for human malaria, are reported. RESULTS Based on calculated median larvicidal concentration (LC50) values at 5 days of treatment, KU‐106 (760 nM) showed an activity against Anopheles larvae similar to that of commercial halofenozide. Induction of the early‐late gene hr3 and docking studies of DBHs in the ligand‐binding pocket of the modelled Anopheles ecdysone receptor indicated that toxicity is caused by the activation of the ecdysone regulatory cascade causing a premature lethal moult. CONCLUSIONS As a result of the similar toxicity exhibited by the experimental compound KU‐106 to that shown by commercial products, the present study demonstrated that the use of DBH compounds to combat harmful dipteran insects, such as mosquitoes, remains unexplored and invites further systematic toxicity tests using other derivatives of the DBH class of compounds.© 2012 Society of Chemical Industry
  PubDate: 2012-12-04T07:32:13.626113-05:
  DOI: 10.1002/ps.3441
Efficacy of six neonicotinoid insecticides alone and in combination with deltamethrin and piperonyl butoxide against pyrethroid‐resistant Aedes aegypti and Anopheles gambiae (Diptera: Culicidae)
- Authors: Frédéric Darriet; Fabrice Chandre
  Pages: n/a - n/a
  Abstract: BACKGROUND In this study, carried out on pyrethroid‐resistant Aedes aegypti and Anopheles gambiae, different combinations containing pyrethroid deltamethrin, piperonyl butoxide (PBO) synergist and six neonicotinoid insecticides (acetamiprid, nitenpyram, thiamethoxam, clothianidin, imidacloprid and thiacloprid) were tested. The bioassays were carried out by tarsal contact on impregnated paper on Ae. aegypti and with impregnated pieces of netting on An. gambiae. RESULTS The combination of deltamethrin and PBO was synergistic against pyrethroid‐resistant Ae. aegypti (LHP) and An. gambiae (VKPR) strains, with 43 and 57% mortality respectively, versus 17 and 12% with deltamethrin alone. On LHP Ae. aegypti, the deltamethrin + PBO + neonicotinoid mixtures generated insecticide efficacies that were either greater (group 1) or lower (group 2) than the deltamethrin + PBO mixture. The tricomponent mixtures made with thiamethoxam, nitenpyram and thiacloprid (70.7, 64.9 and 55.9% mortality respectively) belong to group 1. Group 2 consists of mixtures made with imidacloprid, clothianidin and acetamiprid (28.9, 32.9 and 34.3% mortality respectively). The nettings impregnated with the three tricomponent mixtures of group 1 confirmed the excellent efficacy of these mixtures against An. gambiae VKPR (87–89% mortality). CONCLUSION Deltamethrin + PBO + neonicotinoid (group 1) mixtures induce interesting, efficient synergies, most valuable for the management of mosquito resistance to insecticides.© 2012 Society of Chemical Industry
  PubDate: 2012-12-04T07:15:26.838478-05:
  DOI: 10.1002/ps.3446
Cross‐resistance relationships of the sulfoximine insecticide sulfoxaflor with neonicotinoids and other insecticides in the whiteflies Bemisia tabaci and Trialeurodes vaporariorum
- Authors: Christopher Longhurst; Jonathan M Babcock, Ian Denholm, Kevin Gorman, James D Thomas, Thomas C Sparks
  Pages: n/a - n/a
  Abstract: BACKGROUND Insecticides are important tools for managing damaging insect pests. Compounds that are effective against pests such as the whiteflies Bemisia tabaci and Trialeurodes vaporariorum, which show resistance to a range of insecticidal modes of action (MOA), have particular value as components of resistance management programmes. The sulfoximine insecticides are chemically unique as the first to incorporate a sulfoximine functional group. Sulfoxaflor is the first sulfoximine compound under commercial development for the control of sap‐feeding insects. Its cross‐resistance relationships were investigated by comparing the responses of field‐collected strains with those of insecticide‐susceptible laboratory strains of B. tabaci and T. vaporariorum. RESULTS Sulfoxaflor exhibited very low (less than threefold) resistance ratios (RR) when tested against strains of B. tabaci that produced RR of up to 1000‐fold to imidacloprid and cross‐resistance to other neonicotinoid insecticides. Similarly, sulfoxaflor was not cross‐resistant in a strain of B. tabaci exhibiting resistance to a pyrethroid (deltamethrin) and an organophosphate (profenophos). No cross‐resistance was observed between sulfoxaflor and imidacloprid in T. vaporariorum. One population of the three field strains tested showed slightly reduced susceptibility to sufloxaflor with an RR of 4.17. By comparison, this same population exhibited an RR of more than 23.8‐fold for imidacloprid relative to the susceptible population. CONCLUSION In spite of sharing a target site with neonicotinoids (the nicotinic acetylcholine receptor), sulfoxaflor was largely unaffected by existing cases of neonicotinoid resistance in B. tabaci and T. vaporariorum. Neonicotinoid resistance mechanisms in these whitefly species are known to be primarily based on enhanced detoxification of insecticide. This lack of cross‐resistance indicates that sulfoxaflor is a valuable new tool for the management of sap‐feeding pests already resistant to established insecticide groups.© 2012 Society of Chemical Industry
  PubDate: 2012-11-30T08:31:32.082159-05:
  DOI: 10.1002/ps.3439
Consequences of co‐applying insecticides and fungicides for managing Thrips tabaci (Thysanoptera: Thripidae) on onion
- Authors: Brian A Nault; Cynthia L Hsu, Christine A Hoepting
  Pages: n/a - n/a
  Abstract: Background Insecticides and fungicides are commonly co‐applied in a tank mix to protect onions from onion thrips, Thrips tabaci Lindeman, and foliar pathogens. Co‐applications reduce production costs, but past research shows that an insecticide's performance can be reduced when co‐applied with a fungicide. An evaluation was made of the effects of co‐applying spinetoram, abamectin and spirotetramat with commonly used fungicides, with and without the addition of a penetrating surfactant, on onion thrips control in onion fields. Results Co‐applications of insecticides with chlorothalonil fungicides reduced thrips control by 25–48% compared with control levels provided by the insecticides alone in three of five trials. Inclusion of a penetrating surfactant at recommended rates with the insecticide and chlorothalonil fungicide did not consistently overcome this problem. Co‐applications of insecticides with other fungicides did not interfere with thrips control. Conclusion Co‐applications of pesticides targeting multiple organisms should be examined closely to ensure that control of each organism is not compromised. To manage onion thrips in onion most effectively, insecticides should be applied with a penetrating surfactant, and should be applied separately from chlorothalonil fungicides.© 2012 Society of Chemical Industry
  PubDate: 2012-11-29T07:29:59.499802-05:
  DOI: 10.1002/ps.3444
Toxicity of insecticides to populations of tomato borer Tuta absoluta (Meyrick) from Greece
- Authors: Emmanouil Roditakis; Christina Skarmoutsou, Marianna Staurakaki
  Pages: n/a - n/a
  Abstract: Background Tuta absoluta (Meyrick), in only a few years, has become a serious threat to global tomato production. Depending on the cropping system and infestation pressure, T. absoluta control may rely heavily on insecticide applications. By means of a validated IRAC bioassay method, the toxicity of all insecticides registered for T. absoluta control in Greece has been estimated. A non‐registered pyrethroid insecticide was also included in this study. Results Low heterogeneity was detected in the populations tested with most insecticides. The LC50 ranged from 0.31 to 1.31 mg L−1 for flubendiamide, from 0.12 to 0.53 mg L−1 for chlorantraniliprole, from 0.03 to 0.12 mg L−1 for emamectin benzoate, from 0.08 to 0.26 mg L−1 for spinosad, from 31.8 to 159.5 mg L−1 for metaflumizone, from 1.73 to 17.5 mg L−1 for indoxacarb, from 530 to 2038 mg L−1 for chlorpyriphos and finally from 475 to 794 mg L−1 for cypermethrin. The variability of the LC50 values among the tested populations was low (RR under 5×), except for indoxacarb (RR = 10×). In the absence of a reference strain, comparisons with the recommended label rates were performed. Evidence of potential control failures was detected using probit analysis estimates for cypermethrin, chlorpyriphos and metaflumizone. Conclusions For most registered insecticides, a solid set of baseline data has been presented that can be used in future resistance monitoring studies. The interaction of metaflumizone with T. absoluta has been discussed, and for chlorpyriphos it is suspected that the resistance level is underestimated with the present dataset. Finally, it has been demonstrated that the pyrethroid cypermethrin would provide insufficient control of the pest.© 2012 Society of Chemical Industry
  PubDate: 2012-11-29T07:28:31.955785-05:
  DOI: 10.1002/ps.3442
Pyramiding and evaluation of three dominant brown planthopper resistance genes in the elite indica rice 9311 and its hybrids
- Authors: Jie Hu; Mingxing Cheng, Guanjun Gao, Qinglu Zhang, Jinghua Xiao, Yuqing He
  Pages: n/a - n/a
  Abstract: Background Brown planthopper (BPH), Nilaparvata lugens Stål, is the most devastating insect pest in rice‐producing areas. Three dominant BPH resistance genes (Bph14, Bph15, Bph18) were pyramided into elite indica rice 9311 and its hybrids using marker‐assisted selection. Gene effectiveness was evaluated on the basis of seedling and adult rice resistance, honeydew weight and survival rate of BPH. Results All three genes affected BPH growth and development and antibiotic factors, resulting in both seedling and adult resistance. Bph15 had the greatest effect on conferring resistance to BPH. The results showed an additive effect of pyramiding genes, the order of the gene effect being 14/15/18 ≥ 14/15 > 15/18 ≥ 15 > 14/18 ≥ 14 ≥ 18 > none. The pyramided or single‐gene introgression hybrids showed greater resistance than conventional hybrids, although the heterozygous genotypes had weaker effects than the corresponding homozygous genotypes. Furthermore, field trial data demonstrated that yields of improved 9311 lines were higher than or similar to that of the control under natural field conditions. These improved versions can be immediately used in hybrid improvement and production. Conclusion Compared with controls, pyramided lines and hybrids with three genes showed the strongest resistance to BPH, without a yield decrease. © 2012 Society of Chemical Industry
  PubDate: 2012-11-22T11:33:30.639189-05:
  DOI: 10.1002/ps.3437
Development of new ecological long‐lasting dispensers of semiochemicals for the control of Bactrocera oleae (Rossi)
- Authors: Ricardo Gil‐Ortiz
  Pages: n/a - n/a
  Abstract: Background A new controlled‐release pheromone 1,7‐dioxaspiro[5,5]undecane dispenser has been developed, which is useful for monitoring the population and controlling Bactrocera oleae (Rossi, 1790) (Diptera: Tephritidae). For this purpose, several kinds of dispensers based on attapulgite were designed and tested in this study. Results The designed dispensers, together with the commercial‐brand olive fruit fly ‘Long‐Life Lure’, which was used as a reference, were evaluated in the field, and in parallel were subjected to an accelerated ageing process in a chamber with a constant temperature and air speed. The residual pheromone content was periodically determined by liquid–gas chromatography in order to obtain the half‐life of dispensers and the pheromone release rate. The mesoporous dispenser proved to have the best performance in the field, with a half‐life of 5 months and an average emission speed of 0.6 mg day−1, parameters very close to those obtained with the commercial dispenser tested. In addition, to evaluate the effectiveness of the different dispensers in the field, a duplicate comparative study of captures was designed, and a colony monitoring study of the olive fruit fly was performed using various food and sex attractants. Conclusions Although no significant differences in captures were found between the dispensers tested, the highest number of captures was obtained on average with the mesoporous dispensers demonstrating good pheromone emission characteristics.© 2012 Society of Chemical Industry
  PubDate: 2012-10-29T09:40:55.432043-05:
  DOI: 10.1002/ps.3415
Design, Synthesis, and Fungicidal Activity of 11‐Alkoxyimino‐5,6‐dihydro‐dibenzo[b,e]azepine‐6‐one Derivatives
- Authors: Yan‐shuang Xiao; Xiao‐jing Yan, Yan‐jun Xu, Jia‐xing Huang, Hui‐zhu Yuan, Xiao‐mei Liang, Jian‐jun Zhang, Dao‐quan Wang
  Pages: n/a - n/a
  Abstract: BACKGROUND: Macrocyclic compounds with an oxime ether side chain discovered in Wang's group showed good fungicidal activity. However, the long synthetic route makes the cost too high for them to be developed further as practical fungicides. Alternative compounds with good fungicidal activity and an easy synthesis to the above mentioned macrolactams were sought and a series of 11‐alkoxyimino‐5,6‐dihydro‐dibenzo[b,e]azepine‐6‐one derivatives (4) were designed and bioassayed. RESULTS: The structures were confirmed by 1H NMR, 13C NMR and LC‐MS. The bioassay showed that about half of 11‐alkoxyimino‐5,6‐dihydro‐dibenzo[b,e]azepine‐6‐one derivatives (4) displayed good fungicidal activity against Sclerotinia sclerotiorum (Lib.) de Bary, with EC50 values
  PubDate: 2012-10-24T03:29:42.725096-05:
  DOI: 10.1002/ps.3440
Comparison on RNA interference effect triggered by dsRNA and siRNA in Triboliumcastaneum
- Authors: Jinda Wang; Min Wu, Baoju Wang, Zhaojun Han
  Pages: n/a - n/a
  Abstract: Background: Even though both dsRNA and siRNA were widely used in laboratory studies to knockdown target genes; we found that siRNA rarely triggerred phenotypic changes for intact insects. In this article, we used Tribolium castaneum as model species to compare the efficiency of dsRNA and siRNA and select the efficient way for insect RNAi. Results: Four dsRNA and 10 siRNA targeting at the same 3 genes were tested by checking the suppression of target genes and the deformation of treated insects. The results showed that dsRNA could reduce the expression of target genes by 55‐75% for more than 7 days, and deformed 78.8–87.0% tested larvae. Injection of their corresponding siRNA targeting the same gene did yield about 45% silence of target genes, but only in a short period time from day 2 to day 4, and did not trigger any phenotypic changes. Conclusion: SiRNA were less efficient than their corresponding dsRNA. Most of them could hardly trigger any phenotypic changes due to its temporary silence effect on target genes. Meanwhile, the efficiency of different siRNA varied with their matching sequence, and careful selection were necessary for proper use. Copyright © 2012 Society of Chemical Industry
  PubDate: 2012-10-15T04:06:58.28977-05:0
  DOI: 10.1002/ps.3432