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Journal Cover Pest Management Science
  [SJR: 1.262]   [H-I: 72]   [4 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1526-498X - ISSN (Online) 1526-4998
   Published by John Wiley and Sons Homepage  [1597 journals]
  • Temperature variability is a key component to accurately forecast the
           effects of climate change on pest phenology
    • Authors: Scott C. Merrill; Frank B. Peairs
      Abstract: Background Models describing the effects of climate change on arthropod pest ecology are needed to help mitigate and adapt to forthcoming changes. Challenges arise because climate data are at resolutions that do not readily synchronize with arthropod biology. Here we explain how multiple sources of climate and weather data can be synthesized to quantify the effects of climate change on pest phenology. Results Predictions of phenological events differ substantially between models that incorporate scale‐appropriate temperature variability and models that do not. As an illustrative example, we predicted adult emergence of a pest of sunflower, Cylindrocopturus adspersus (LeConte). Predictions of the timing of phenological events differed by an average of 11 days between models with different temperature variability inputs. Moreover, as temperature variability increases developmental rates accelerate. Conclusions Our work details a biologically‐relevant phenology modeling approach for pests with results designed to help mitigate the effects of climate change. Results show that selection of scale appropriate temperature data is of more importance than selecting a climate change emission scenario or Representative Concentration Pathway. Predictions derived without appropriate temperature variability inputs will likely result in substantial phenological event miscalculations. Additionally, results suggest that increased temperature instability will lead to accelerated pest development.
      PubDate: 2016-05-16T02:50:43.347123-05:
      DOI: 10.1002/ps.4320
       
  • Study of the efficiency of anticoagulant rodenticides to control Mus
           musculus domesticus introgressed with Mus spretus Vkorc1
    • Abstract: BACKGROUND Antivitamin K anticoagulant (AVK) rodenticides are commonly used to control rodent pests worldwide. They specifically inhibit the VKORC1 enzyme essential for the recycling of vitamin K, and thus prevent blood clotting and cause death by haemorrhage. Numerous mutations or polymorphisms of the Vkorc1gene were reported in rodents and some lead to resistance to rodenticides. In house mice (Mus musculus domesticus), adaptative introgression of the Vkorc1 gene from the Algerian mouse (Mus spretus) was reported. This adaptative introgression causes the substitution of four amino acids in M. musculus domesticus. RESULTS The consequences of introgression were assessed by (i) the characterization of the in vivo resistant phenotype of adaptative Vkorc1spr‐introgressed mice, (ii) the characterization of the ex vivo resistance phenotype of the liver VKOR activity and (iii) the comparison of these results with the properties of recombinant VKORC1spr protein expressed in yeast. The resistance factor (from 1 to 120) induced by the four introgressed polymorphisms obtained using these three approaches was dependent on the used AVKs but were highly correlated among the three approaches. CONCLUSION The 4 introgressed polymorphisms were clearly the cause of the strong resistant phenotype observed in the field. In the context of strong selection pressure due to the extensive use of AVK, this resistant phenotype may explain the widespread distribution of this genotype from Spain to Germany.
      PubDate: 2016-05-16T02:50:16.806926-05:
      DOI: 10.1002/ps.4319
       
  • Structure, function and management of semi‐natural habitats for
           conservation biological control: A review of European studies
    • Abstract: Different semi‐natural habitats occur on farmland and it is the vegetation's traits and structure that subsequently determine their ability to support natural enemies and their associated contribution to conservation biocontrol. New habitats can be created and existing ones improved with agri‐environment scheme funding in all EU member states. Understanding the contribution of each habitat type can aid the development of conservation control strategies. Here we review the extent to which the predominant habitat types in Europe support natural enemies, whether this results in enhanced natural enemy densities in the adjacent crop, and whether this leads to reduced pest densities. Considerable variation exists in the available information for the different habitat types and trophic levels. Natural enemies within each habitat were the most studied, with less information on whether they were enhanced in adjacent fields, whilst their impact on pests was rarely investigated. Most information was available for woody and herbaceous linear habitats, yet not for woodland that can be the most common semi‐natural habitats in many regions. While the management and design of habitats offers potential to stimulate conservation biocontrol we also identified knowledge gaps. A better understanding of the relationship between resource availability and arthropod communities across habitat types, the spatio‐temporal distribution of resources in the landscape, and interactions with other factors that play a role in pest regulation could contribute to an informed management of semi‐natural habitats for biocontrol.
      PubDate: 2016-05-14T00:16:45.866127-05:
      DOI: 10.1002/ps.4318
       
  • The interactions between piperonyl butoxide and analogues with the
           metabolic enzymes FE4 and CYP6CY3 of the green peach aphid Myzus persicae
           (Hemiptera: Aphididae)
    • Authors: Michela Panini; Francesco Tozzi, Chris Bass, Christoph T. Zimmer, Linda Field, Valerio Borzatta, Emanuele Mazzoni, Graham Moores
      Abstract: BACKGROUND Piperonyl butoxide (PBO) is a well‐known insecticide synergist capable of interacting with phase 1 metabolic enzymes, specifically esterases and cytochrome P450s. In this study, structure activity relationship (SAR) analyses were used to characterise the interaction of around 30 analogues of PBO with the esterase FE4 and the P450 CYP6CY3 from insecticide resistant Myzus persicae (Sulzer), in order to predict the synthesis of more potent inhibitors. RESULTS Enzyme inhibition studies were performed against esterase and oxidase activities and together with in silico modelling, key activity determinants of the analogues were identified and optimised. Novel analogues were then designed and synthesised, some of which showed greater inhibition against both enzymatic systems: specifically, dihydrobenzofuran moieties containing an alkynyl side chain and a butyl side chain against FE4, and benzodioxole derivatives with a propyl/butyl side chain and an alkynyl ether moiety for CYP6CY3. CONCLUSIONS In vitro assays identified potential candidate synergists with high inhibitory potency. The in vivo confirmation of such results will allow consideration for a possible use in agriculture.
      PubDate: 2016-05-13T04:50:49.296776-05:
      DOI: 10.1002/ps.4314
       
  • The Importance of Regulatory Data Protection or Exclusive Use and other
           forms of Intellectual Property Rights in the Crop Protection Industry
    • Authors: Michael J. Carroll
      Abstract: BACKGROUND In order for a chemical plant protection product to be authorised for sale a registration dossier has to be assembled to demonstrate safety and efficacy to the satisfaction of government regulators. These studies and tests are protected for a period of 10 years in Europe, North America and some other jurisdictions from the date of first product authorisation so that only the data owner can gain commercial benefit from the data. RESULTS After first product authorisation the USA, Canada, Australia and Brazil give 10 years of data protection exclusive use for the safety and efficacy data necessary for the regulatory decision. At subsequent regulatory review financial compensation is payable to the data owner for new studies. The EU system offers sequential regulatory data protection exclusive use with compensation for vertebrate studies which can lead to confusion. CONCLUSION Data protection exclusive use is a time limited intellectual property right that gives the data owner a period of 10 years in Europe and North America whereby no other company can use the data for commercial gain. Subsequent regulatory reviews should not result in further periods of regulatory data protection exclusive use but compensation should be payable to the data generator.
      PubDate: 2016-05-13T04:50:45.944898-05:
      DOI: 10.1002/ps.4316
       
  • Not in my backyard: effectiveness of outdoor residual spraying from
           hand‐held sprayers against the mosquito Aedes albopictus in Rome,
           Italy
    • Abstract: BACKGROUND WHO guidelines state that adulticide interventions are recommended only in case of disease outbreak. However, peridomestic sprayings are carried out routinely to reduce Aedes albopictus (Skuse) nuisance, at least in Italy. Failing in keeping low adult abundance overtime triggers the need for further applications. The aim of the study was to investigate the effectiveness of a common control strategy routinely performed by citizens in highly infested urban sites inside the metropolitan city of Rome using a freely purchasable pyrethroid and a hand‐held sprayer. Moreover, the effectiveness evaluated in three field experiments was compared to the one achieved by blending the pyrethroid with a new carbon‐based liquid additive. RESULTS 86% post‐treatment reduction in Ae. albopictus abundance was observed in gravid and host‐seeking females, while the population recovery time was 10 days. Blending the insecticide with the additive lengthened mosquito recovery time over 14 days. CONCLUSION Peridomestic sprayings largely reduce mosquito population immediately after treatment but fail to keep low mosquito abundance on a longer period, partially explaining the uncontrolled repetitions of treatments. An optimal control application could benefit from research in the field of additive to improve the mosquito abatement and the overtime performances of pyrethroids.
      PubDate: 2016-05-13T04:50:43.673534-05:
      DOI: 10.1002/ps.4315
       
  • A generalised individual‐based algorithm for modelling the evolution
           of quantitative herbicide resistance in arable weed populations
    • Authors: Chun Liu; Melissa E. Bridges, Shiv S. Kaundun, Les Glasgow, Micheal D. K. Owen, Paul Neve
      Abstract: BACKGROUND Simulation models are useful tools for predicting and comparing the risk of herbicide resistance in weed populations under different management strategies. Most existing models assume a monogenic mechanism governing herbicide resistance evolution. However, growing evidence suggests that herbicide resistance is often inherited in a polygenic or quantitative fashion. Therefore, we constructed a generalised modelling framework to simulate the evolution of quantitative herbicide resistance in summer annual weeds. RESULTS Real‐field management parameters based on Amaranthus tuberculatus (Moq.) Sauer (syn. rudis) control with glyphosate and mesotrione in the Midwestern U.S. maize‐soybean agroecosystems demonstrated that the model can represent evolved herbicide resistance in realistic timescales. Sensitivity analyses showed that genetic and management parameters were impactful on the rate of quantitative herbicide resistance evolution, whilst biological parameters such as emergence and seed bank mortality were less important. CONCLUSION The simulation model provides a robust and widely applicable framework for predicting the evolution of quantitative herbicide resistance in summer annual weed populations. The sensitivity analyses identified weed characteristics that would favour herbicide resistance evolution, including high annual fecundity, large resistance phenotypic variance and pre‐existing herbicide resistance. Implications for herbicide resistance management and potential use of the model are discussed.
      PubDate: 2016-05-13T04:50:33.370933-05:
      DOI: 10.1002/ps.4317
       
  • Larval Western bean cutworm feeding damage encourages the development of
           Gibberella ear rot on field corn
    • Authors: Nicole S. Parker; Nolan R. Anderson, Douglas S. Richmond, Elizabeth Y. Long, Kiersten A. Wise, Christian H. Krupke
      Abstract: BACKGROUND A two year study was conducted to determine if western bean cutworm (Striacosta albicosta Smith) (WBC) larval feeding damage increases severity of the fungal disease Gibberella ear rot (Fusarium graminearum (Schwein.) Petch in field corn (Zea mays L.). The effect of a QoI fungicide, pyraclostrobin, on Gibberella ear rot severity and mycotoxin production, both with and without WBC pressure, was also evaluated. The impact of each variable was assessed individually and in combination to determine the effect of each upon ear disease severity. RESULTS There was a positive correlation between the presence of WBC larvae in field corn and Gibberella ear rot severity under inoculated conditions in two years of the experiment. An application of pyraclostrobin did not impact Gibberella ear rot development when applied at corn growth stage R1 (silks first emerging). CONCLUSION Feeding damage from WBC larvae significantly increases the development of F. graminearum in field corn. We conclude that an effective integrated management strategy for Gibberella ear rot should target the insect pest first, in an effort to limit disease severity and subsequent mycotoxin production by F. graminearum in kernels.
      PubDate: 2016-05-09T09:11:43.117516-05:
      DOI: 10.1002/ps.4313
       
  • Fitness costs and stability of Cry1Fa resistance in Brazilian populations
           of Spodoptera frugiperda
    • Abstract: BACKGROUND The presence of fitness costs of resistance to Bacillus thuringiensis (Bt) insecticidal proteins in insect populations may delay or even reverse the local evolution of insect resistance to Bt transgenic crops, deserving rigorous investigation. Here we assessed the fitness costs associated with Cry1Fa resistance in two fall armyworm strains [Spodoptera frugiperda (Lepidoptera: Noctuidae)] derived from field collections in different Brazilian regions and further selected in the laboratory for high levels of resistance to Cry1Fa using leaves of TC1507 corn. RESULTS Fitness components were compared using paired resistant and susceptible strains with similar genetic background and F1 generations from reciprocal crosses, all of them reared on non‐transgenic corn leaves. No apparent life‐history costs in the larval stage were observed in the Bt resistant strains. Moreover, the resistance remained stable for seven generations in the absence of selection with no decrease in the proportion of resistant individuals. Larval respiration rates were also similar between resistant and susceptible homozygotes, and heterozygotes displayed respiration rates and demographic performance equal or superior to that of susceptible homozygotes. CONCLUSION In combination, these results indicate lack of strong fitness costs associated with resistance to Cry1Fa in the fall armyworm strains studied. These findings suggest that Cry1Fa resistance in S. frugiperda populations is unlikely to be counter‐selected in Cry1Fa‐free environments.
      PubDate: 2016-05-05T02:05:35.437732-05:
      DOI: 10.1002/ps.4312
       
  • It Takes a Team: Reflections on Insecticide Discoveries, Toxicological
           Problems and Enjoying the Unexpected
    • Authors: Keith D. Wing
      Abstract: ADME (Absorbtion/Distribution/Metabolism/Excretion)–related studies are mandatory in agrochemical development/registration, but can also play a valuable role in the discovery process. In combination with target site potency, bioavailability/ADME characteristics determine agrochemical bioactivity and selectivity, and these concerns can dictate the fate of a discovery lead area. Bioavailability/ADME research was critical to the eventual commercialization of three different insecticide chemistries examined in this paper. In one situation, improved systemicity in anthranilic diamides was required to expand pest spectrum. In another, ADME tools were needed to improve the selective toxicity and nontarget safety of sodium channel blocker insecticides. Finally, differential ADME characteristics of two classes of hormone agonists dictated differential insecticidal activity, and were useful in optimizing the dibenzoylhydrazine ecdysone agonists. ADME discovery research will help companies to advance novel, efficacious and selective agrochemicals, but organizational patience and a desire to understand lead areas in depth are required.
      PubDate: 2016-05-05T02:05:27.994215-05:
      DOI: 10.1002/ps.4311
       
  • Laboratory studies of insecticide efficacy and resistance in Drosophila
           suzukii (Matsumura) (Diptera: Drosophilidae) populations from British
           Columbia, Canada
    • Abstract: BACKGROUND Drosophila suzukii (Matsumura), spotted wing drosophila (SWD), control can be improved with better knowledge of insecticide efficacy, timing of sprays, and rotations with registered products during the crop year. An efficacy bioassay was applied to study the dose–response of adult laboratory‐reared SWD collected from a cherry orchard in British Columbia (BC), Canada, to 11 insecticides. RESULTS Age and sex specific toxicities with the most effective insecticide, malathion, determined that older male SWD were significantly more susceptible than females. The selection for polygenic resistance to malathion using repeated exposure to sub‐lethal concentrations with both the original and an additional blueberry‐collected population of laboratory reared SWD determined no significant difference in susceptibility after 30 generations. CONCLUSION Possible reasons reported in Drosophila melanogaster studies where resistance did not occur after insecticide selection included avoidance and associated microbial complexes. The low level of malathion‐resistance observed in the selected SWD populations and a field‐collected population is useful information in the development of insecticide resistance management programs.
      PubDate: 2016-05-05T02:00:24.38099-05:0
      DOI: 10.1002/ps.4310
       
  • An artificial diet containing plant pollen for the mealybug predator
           Cryptolaemus montrouzieri
    • Authors: Jiaqin Xie; Hongsheng Wu, Hong Pang, Patrick De Clercq
      Abstract: BACKGROUND The specialist predatory ladybird Cryptolaemus montrouzieri is an effective natural enemy of mealybugs and plays a key role in the biological control of these pests. However, its mass production is complicated by the dependence on parallel cultures of mealybugs or the need for Ephestia kuehniella eggs as an expensive factitious prey. RESULTS Here we developed a pollen‐based artificial food for the predator to lower its dependence on natural prey. We found that this artificial diet was an effective alternative food for larvae and adults of this predator. The artificial food not only supported the development and reproduction of the predator in the first generation (F0) but also in the next generation (F1). Although the developmental time and preoviposition period of C. montrouzieri on the artificial food were ca. 1.5 days and 4 days longer than on the natural prey, the citrus mealybug Planococcus citri, respectively, its immature survival, fecundity and egg hatch were similar to that on mealybugs. In addition, adult C. montrouzieri maintained on natural or artificial food had a similar starvation resistance. CONCLUSIONS Our results suggest that the pollen‐based artificial diet can be used as an alternative food in the rearing of C. montrouzieri, and indicate its potential to support the mass production and wider application of this predator in biological control programs.
      PubDate: 2016-05-05T02:00:20.778774-05:
      DOI: 10.1002/ps.4309
       
  • A Retrospective Look at Anthranilic Diamide Insecticides: Discovery and
           Lead Optimization to Chlorantraniliprole and Cyantraniliprole
    • Authors: Thomas P. Selby; George P. Lahm, Thomas M. Stevenson
      Abstract: Anthranilic diamides are an important commercial synthetic class of insecticides (IRAC Group 28) that bind to the ryanodine receptor with selective potency against insect versus mammalian forms of the receptor. The first commercialized diamide, chlorantraniliprole, has exceptional activity against Lepidopteran pests. The second anthranilamide product, cyantraniliprole, has excellent cross‐spectrum activity against a range of insect orders, including both Lepidopteran and Hemipteran pests. Here, a retrospective look is presented on the discovery of the class along with chemistry highlights of the lead evolution to both products.
      PubDate: 2016-05-05T01:55:24.41971-05:0
      DOI: 10.1002/ps.4308
       
  • Proposal for a unified nomenclature for target site mutations associated
           with resistance to fungicides
    • Authors: W Mair; F Lopez Ruiz, G Stammler, W Clark, F Burnett, D Hollomon, H Ishii, T. S Thind, J.K. M Brown, B Fraaije, H Cools, M Shaw, S Fillinger, EM Terrado, G Schnabel, A. Mehl, RP Oliver
      Abstract: Evolved resistance to fungicides is a major problem limiting our ability to control agricultural, medical and veterinary pathogens and is frequently associated with substitutions in the amino acid sequence of the target protein. The convention for describing amino‐acid substitutions is to cite the wild type amino acid, the codon number and the new amino acid, using the one letter amino acid code. It has frequently been observed that orthologous amino acid mutations have been selected in different species by fungicides from the same mode of action class, but the amino acids have different numbers. These differences in numbering arise from the different lengths of the proteins in each species. The purpose of the current paper is to propose a system for unifying the labelling of amino acids in fungicide target proteins. To do this we have produced alignments between fungicide target proteins of relevant species fitted to a well‐studied “archetype” species. Orthologous amino acids in all species are then assigned numerical “labels” based on the position of the amino acid in the archetype protein.
      PubDate: 2016-05-04T04:41:32.801069-05:
      DOI: 10.1002/ps.4301
       
  • Novel and current rodenticides for pocket gopher Thomomys spp. management
           in vineyards: what works?
    • Authors: Roger A. Baldwin; Ryan Meinerz, Gary W. Witmer
      Abstract: Background Rodenticides are often included as part of an IPM approach for managing pocket gophers (Thomomys spp.) given that they are relatively quick and inexpensive to apply. Strychnine has historically been the most effective toxicant for pocket gophers, but its use is currently limited in the U.S.; alternative registered toxicants have not proven effective. Recent research with baits containing cholecalciferol plus anticoagulant toxicants proved effective against pocket gophers in a lab setting. Therefore, we established a field study to compare cholecalciferol plus anticoagulant combinations (0.03% cholecalciferol plus 0.005% diphacinone [C + D], 0.015% cholecalciferol plus 0.0025% brodifacoum [C+B1], 0.03% cholecalciferol plus 0.0025% brodifacoum [C+B2]) to strychnine (0.5%) for pocket gopher management. Results Strychnine treatments resulted in 100% efficacy after two treatment periods. Both C + D and C+B2 resulted in efficacy significantly greater than 70% after two treatment periods (83% and 75%, respectively). Efficacy from C+B1 (85%) was not significantly greater than 70%, but did yield high overall efficacy as well. Conclusion Although strychnine remains the most effective rodenticide for pocket gopher control, the cholecalciferol plus anticoagulant baits tested would be a good alternative when strychnine is unavailable. C + D may be the best option given that it uses a first‐generation anticoagulant as the synergist.
      PubDate: 2016-05-03T00:41:27.404309-05:
      DOI: 10.1002/ps.4307
       
  • Competition between the phytophagous stink bugs Euschistus heros and
           Piezodorus guildinii in soybeans
    • Abstract: BACKGROUND The abundance and contribution of the Neotropical brown stink bug, Euschistus heros (F.), and the redbanded stink bug, Piezodorus guildinii (West.), to the composition of insect pests of soybean, Glycine max (L.), fields have changed both spatially and temporally in Neotropical soybean production areas. Therefore, we assessed the competitiveness of each species in direct competition experiments following an additive series. We performed mixed (adult) insect infestations in soybean plants and evaluated the fitness of each species and the soybean yield. RESULTS While the competitive ability of E. heros was significantly compromised by increments in conspecifics and heterospecifics (i.e., P. guildinii), the competitive ability of P. guildinii was compromised by the presence of heterospecifics (i.e., E. heros). The reproductive output of P. guildinii remained unaffected by increments of E. heros or of P. guildinii. Intriguingly, despite the fact that P. guildinii apparently lost the competition with E. heros, almost no pod production was observed in any plant colonized by the former. CONCLUSIONS The higher abundance of E. heros on Neotropical soybean fields seems to result from higher competitive ability than its heterospecific competitor P. guildinii, which may prevent the higher losses caused by P. guildinii.
      PubDate: 2016-04-30T05:05:41.457121-05:
      DOI: 10.1002/ps.4306
       
  • ACIBENZOLAR‐S‐METHYL MAY PREVENT VECTOR‐MEDIATED
           FLAVESCENCE DORÉE PHYTOPLASMA TRANSMISSION, BUT IS INEFFECTIVE IN
           INDUCING RECOVERY OF INFECTED GRAPEVINES
    • Abstract: BACKGROUND Acibenzolar‐S‐methyl (BTH), a functional analog of Salicylic Acid (SA), is known to elicit a systemic resistance across a broad range of plant–pathogen interactions but, so far, it was not tested against Flavescence dorée (FDP), one of the most devastating grapevine diseases. Aims of this work were to evaluate the activity of BTH in preventing FDP transmission by the insect vector and in inducing recovery of infected grapevines. RESULTS Repeated applications of 2 mM BTH to test grapevine cuttings (cv Barbera) exposed to adults of the infectious vector, Scaphoideus titanus Ball, reduced the rate of infected plants. The effect was not recorded following similar BTH applications to highly susceptible young in vitro propagated vines. A high natural recovery rate (more than 70%) was observed over a three‐year‐period in field‐infected grapevines of the same cv. Under these conditions, BTH repeated applications over the whole period clearly failed to increase recovery of field‐infected grapevines. CONCLUSION Following a three‐year experiment, it can be concluded that, although high doses and repeated applications of BTH reduced vector transmission of FDP, BTH was ineffective in inducing recovery of FDP‐infected grapevines cv Barbera under field conditions.
      PubDate: 2016-04-27T01:31:09.45451-05:0
      DOI: 10.1002/ps.4303
       
  • Vkorc1‐sequencing suggests anticoagulant resistance in rats in New
           Zealand
    • Abstract: BACKGROUND Anticoagulant toxins are used globally to control rats. Resistance of Rattus species to these toxins now occurs in at least 18 countries in Europe, America, and Asia. Resistance is often associated with single nucleotide polymorphisms (SNP) in the Vkorc1 gene. This study gives a first overview of the distribution and frequency of Vkorc1 SNPs in rats in New Zealand. New Zealand is unusual in having no native rodents but three species of introduced Rattus – norvegicus Berk., rattus L. and exulans Peale. RESULTS Sequence variants occurred in at least one species of rat at all 30 of the sites sampled. Three new SNPs were identified, one in kiore and two in ship rats. No SNPs previously associated with resistance were found in Norway rats or kiore, but seven ship rats were heterozygous and one homozygous for the A74T variant. Its resultant Tyr25Phe mutation has previously been associated with resistance to both first and second generation anticoagulants in ship rats in Spain. CONCLUSIONS This is the first evidence of potential resistance to anticoagulant toxins in rats in New Zealand. Further testing using blood clotting response times in dosed rats is needed to confirm resistance potentially conferred by the Tyr25Phe mutation. Assessment is also needed of the potential of the other non‐synonymous variants (Ala14Val, Ala26Val) recorded in this study to confer resistance to anticoagulant toxins.
      PubDate: 2016-04-27T01:30:55.563106-05:
      DOI: 10.1002/ps.4304
       
  • Linking pollen quality and performance of Neoseiulus californicus (Acari:
           Phytoseiidae) in two‐spotted spider mite management programmes
    • Authors: Mostafa Khanamani; Yaghoub Fathipour, Ali Asghar Talebi, Mohammad Mehrabadi
      Abstract: BACKGROUND It has been shown that pollen as a dietary supplement may increase the establishment of generalist predatory mites, and therefore pest control by these mites can be provided. Life table studies were performed to evaluate the nutritional value of seven different pollens (almond, castor‐bean, date‐palm, maize, bitter‐orange, sunflower and mixed bee pollen) as a supplementary food source for the spider mite predator, Neoseiulus californicus McGregor. In addition, the nutritional quality of each pollen species was assessed through morphological and chemical analysis. RESULTS Preadult duration was longer when the predator fed on castor‐bean pollen (10.01 days) and bee pollen (9.94 days) compared with the others (5.58 ‐7.27 days). The cohort reared on almond pollen had the highest intrinsic rate of increase (r) (0.231 day−1), and those on mixed bee pollen had the lowest r (0.005 day−1). The levels of nutritional content (sugar, lipid and protein) were significantly different among tested pollens. CONCLUSIONS Comparison of N. californicus life table parameters on different diets revealed that the almond pollen (and after that the maize pollen) was a more suitable diet than the others. These findings will be useful to develop appropriate strategies for conservation of N. californicus to control the spider mites.
      PubDate: 2016-04-27T01:30:25.414719-05:
      DOI: 10.1002/ps.4305
       
  • Influence of Soil Properties and Soil Moisture on the Efficacy of
           Indaziflam and Flumioxazin on Kochia scoparia L.
    • Authors: Derek Sebastian; Scott Nissen, Phil Westra, Dale Shaner, Greg Butters
      Abstract: BACKGROUND Kochia (Kochia scoparia L.) is a highly competitive, non‐native weed found throughout the western US. Flumioxazin and indaziflam are two broad spectrum preemergence herbicides that can control kochia in a variety of crop and non‐crop situations; however, under dry conditions, these herbicides sometimes fail to control this important weed. There is very little information describing the effect of soil properties and soil moisture on the efficacy of these herbicides. RESULTS Soil organic matter (SOM) explained the highest proportion of variability in predicting the herbicide dose required for 80 percent kochia growth reduction (GR80) for flumioxazin and indaziflam (r2 = 0.72 and 0.79, respectively). SOM had a larger impact on flumioxazin phytotoxicity compared to indaziflam. Flumioxazin and indaziflam kochia phytotoxicity was greatly reduced at soil water potentials below −200 kPa. CONCLUSION Kochia can germinate at soil moisture potentials below the moisture required for flumioxazin and indaziflam activation, which means that kochia control is greatly influenced by the complex interaction between soil physical properties and soil moisture. This research can be used to better understand how and why some weeds, like kochia, are so difficult to manage even with herbicides that normally provide excellent control.
      PubDate: 2016-04-25T00:30:36.611993-05:
      DOI: 10.1002/ps.4300
       
  • Dust drift reduction effect of an air conveyor kit (dual pipe deflector)
           mounted on different maize pneumatic drills
    • Authors: Marco Manzone; Paolo Balsari, Paolo Marucco, Mario Tamagnone
      Abstract: BACKGROUND All maize drills produce a fine dust due to the abrasions of the seed coating that occur inside the seeding element. Nevertheless, the air stream generated by the fan of pneumatic drills – necessary to create a depression in the sowing element of the machine and to guarantee a correct seeds deposition – can blow away the solid particles detached from the seeds. In order to reduce this phenomena, coated maize seeds company (Syngenta®) has set up an ad hoc kit “dual pipe deflector” that easy a fits different pneumatic drills (also old drills). In this study, the efficiency of this kit and the influence of different drills types on the kit effects in reducing the environmental contamination, were evaluated using three different pneumatic seed drills models. RESULTS The research showed that dual pipe deflector installed on the drill in standard configuration did not change the seeder performance and using this kit on pneumatic drills, independent of their design, it is possible to reduce up to 69% the amount of dust drift with respect to the conventional machine set up. CONCLUSION Dual pipe deflector, under conditions explained in this experimentation, showed good performances with all types of maize pneumatic drills used. Independent of the seeder model on which is mounted, it is able to obtain similar results highlighting an high operative versatility.
      PubDate: 2016-04-25T00:30:31.180102-05:
      DOI: 10.1002/ps.4302
       
  • Phytotoxicity of aminobisphosphonates targeting both
           δ1‐pyrroline‐5‐carboxylate reductase and glutamine
           synthetase
    • Abstract: BACKGROUND Dual‐target inhibitors may contribute to the management of herbicide‐resistant weeds and avoid or delay the selection of resistant biotypes. Some aminobisphosphonates inhibit the activity of both glutamine synthetase and δ1‐pyrroline‐5‐carboxylate (P5C) reductase in vitro, but the relevance of the latter in vivo has not been proven, yet. This study aimed at demonstrating that these compounds can block also proline synthesis in planta. RESULTS Two aminophosphonates, namely 3,5‐dichlorophenylamino‐methylenebisphosphonic acid and 3,5‐dibromophenylaminomethylenebis‐phosphonic acid (Br2PAMBPA), showed inverse effectiveness against the two partially purified target enzymes from rapeseed. The compounds showed equipotency in inhibiting the growth of rapeseed seedlings and cultured cells. The analysis of amino acid content in treated cells showed a strong reduction of glutamate and glutamate‐related amino acid pools, but a milder effect on free proline. In the case of Br2PAMBPA, toxic P5C levels accumulated in treated seedlings, proving that the inhibition of P5C reductase takes place in situ. CONCLUSIONS Phenyl‐substituted aminobisphosphonates may be regarded as true dual‐target inhibitors. Their use to develop new active principles for crop protection could consequently represent a tool to address the problem of target‐site resistance among weeds.
      PubDate: 2016-04-22T03:55:22.756387-05:
      DOI: 10.1002/ps.4299
       
  • Impact of Atrazine Prohibition on the Sustainability of Weed Management in
           Wisconsin Maize Production
    • Authors: Fengxia Dong; Paul D. Mitchell, Vince M. Davis, Ross Recker
      Abstract: BACKGROUND Controversy has surrounded atrazine due to its susceptibility to leaching and runoff, with regular calls for a ban or restrictions on its use. In the context of a decreasing trend in the percentage of US maize using no‐till since 2008, coinciding with the trend of glyphosate‐resistant weeds becoming problematic in the Midwestern US, we empirically examine how atrazine use restrictions impacted the diversity of weed management practices used by Wisconsin maize farmers. RESULTS Using survey data from farms inside and outside atrazine prohibition areas, we found that prohibiting atrazine did not directly impact tillage practices, but rather it increased adoption of herbicide‐resistant seed, which then increased adoption of conservation tillage systems. We also found that prohibiting atrazine and using herbicide‐resistant seed decreased the number of herbicide sites of action used. CONCLUSIONS The results indicate that prohibiting atrazine reduced the diversity of weed management practices, which increased the risk of herbicide resistance. Our concern is that a regulatory policy to address one issue (atrazine in groundwater) has induced farmer responses that increase problems with another issue (herbicide‐resistant weeds) that longer term will contribute to water quality problems from increased soil erosion and offset the initial benefits.
      PubDate: 2016-04-21T07:25:44.051588-05:
      DOI: 10.1002/ps.4298
       
  • The efficacy of Beauveria bassiana, jasmonic acid and chlorantraniliprole
           
    • Authors: Aneela Younas; Zaeema Khan, Waqas Wakil, Muhammad Shaaban, Sean Michael Prager
      Abstract: BCKGROUND A robust integrated pest management (IPM) program is needed to reduce the use of insecticides in controlling Helicoverpa armigera. Therefore, a two year field study was conducted to evaluate the use of alternative control measures (biochemical use) for H. armigera relative to exclusively use of chemical insecticides. The entomopathogenic fungi Beauveria bassiana, jasmonic acid and the insecticide chlorantraniliprole were each applied twice during the chickpea‐growing season. RESULTS All three applied materials (either alone or combined) significantly (p ≤ 0.05) reduced the larval population of H. armigera and pod infestation. Effects increased with time and the maximum difference was observed 7 days after the second application in each year. The lowest numbers of larvae per plant and pod infestation were in the B. bassiana 3.21 × 106 + chlorantraniliprole treatment in both 2009/2010 and 2010/2011 year. The reduction in the larval population and pod infestation increased chickpea yield and the highest yield in both seasons, and the maximum yield was obtained in the B. bassiana 3.21 × 106 + chlorantraniliprole treatment. The populations of natural enemies were highest in the jasmonic acid treatment. CONCLUSION The results suggest that B. bassiana, jasmonic acid and chlorantraniliprole may be useful components for H. armigera IPM strategy.
      PubDate: 2016-04-21T07:20:20.954756-05:
      DOI: 10.1002/ps.4297
       
  • Methoxyfenozide resistance of house fly, Musca domestica L. (Diptera:
           Muscidae): Cross‐resistance patterns, stability and associated
           fitness costs
    • Authors: Rizwan Mustafa Shah; Sarfraz Ali Shad, Naeem Abbas
      Abstract: BACKGROUND House fly, Musca domestica L., (Diptera: Muscidae) is an insect pest of public health and veterinary importance with ability to develop resistance to insecticides. Methoxyfenozide, an ecdysone agonist, is a bio‐rational insecticide being used for the management of various insect pests, including house flies. To design an effective resistance management strategy, life history traits based on laboratory observations were established for methoxyfenozide resistant (MXY‐SEL), unselected counterpart (UNSEL) and reciprocal cross strains of house fly. RESULTS The MXY‐SEL developed a resistance ratio of 160.99 after 30 generations of selection with methoxyfenozide compared to the UNSEL. The MXY‐SEL showed very low cross‐resistance to cyromazine, fipronil and chlorpyrifos and no cross‐resistance to spinosad and bifenthrin, when compared to the Methoxy‐Field population. Resistance to methoxyfenozide, cyromazine, fipronil, spinosad, chlorpyrifos, and bifenthrin was unstable in the MXY‐SEL. The MXY‐SEL had a reduced relative fitness (0.31), with lower hatchability, lower number of next generation larvae, lower intrinsic rate of natural increase, and lower biotic potential compared to the UNSEL. CONCLUSIONS Disadvantageous life history traits of the MXY‐SEL suggest that development of resistance to methoxyfenozide has considerable costs of fitness for this strain. Moreover, the unstable resistance to tested chemicals provides useful information to preserve the efficacy of these chemicals.
      PubDate: 2016-04-21T06:55:26.078672-05:
      DOI: 10.1002/ps.4296
       
  • Diet quality affects bait performance in German cockroaches (Dictyoptera:
           Blattellidae)
    • Authors: Alexander E. Ko; Coby Schal, Jules Silverman
      Abstract: BACKGROUND Bait formulations are widely used to control German cockroach (Blattella germanica) populations. To perform optimally, these formulations must compete favorably with non‐toxic alternative foods present within the insect's habitat. We hypothesized that the nutritional history of cockroaches and their acceptance or avoidance of glucose would affect their food preference and thus bait efficacy. To test this hypothesis, we conducted a controlled laboratory experiment, first providing glucose‐accepting and glucose‐averse cockroaches nutritionally defined diets and then offering them identical diets containing the insecticide hydramethylnon as a bait proxy to evaluate the effect of diets of differing macronutrient composition on bait performance. RESULTS The interaction between diet composition and bait composition affected the survival of adult males as well as first instar nymphs exposed to excretions produced by these males. Survival analyses indicated different responses of glucose‐averse and glucose‐accepting insects, but generally, any combination of diet and bait that resulted in high diet intake and low bait intake decreased secondary kill. CONCLUSIONS This study represents a comprehensive examination of the effect of alternative foods on bait efficacy. We suggest that disparities between the nutritional quality of baits and the foods that are naturally available could profoundly impact the management of German cockroach infestations.
      PubDate: 2016-04-21T06:55:22.858708-05:
      DOI: 10.1002/ps.4295
       
  • The influence of time and distance traveled by bed bugs, Cimex
           lectularius, on permethrin uptake from treated mattress liners
    • Authors: Stephen A. Kells; Sabrina N. Hymel
      Abstract: Background Residual insecticides interrupt dispersal of bed bugs (Cimex lectularius, L.), but one of the issues encountered with residual applications is understanding the uptake of active residues by the insect. This study determined permethrin uptake by bed bugs walking on the ActiveGuard® Mattress Liner product, via a combination of video‐recording in arenas and gas chromatography analyses. Results The best model for estimating permethrin uptake utilized a covariance model (r2 = 0.469) with two factors: time of exposure (F1,55 = 2.44, P < 0.001) and distance traveled (F1,55 = 0.30 P = 0.0460). Bed bug permethrin‐uptake was 15.1 (95 % CI: 10.3 – 22.1) ng insect−1 within 1 min exposure; 21.0 (15.0, 31.0) ng insect−1 in 10 min; and, ≈42 (29.8, 60.6) ng insect−1 in ≥ 50 min exposure. Correcting for % recovery, these values would be would be increased by a factor of 1.21. Conclusion This permethrin‐treated fabric provides a surface from which bed bugs begin to rapidly absorb permethrin on contact and within the first 1 cm of travel. Variability in uptake was likely a result of grooming and thigmotaxis, and future work should use quantitative methods to study behaviors and formulations that increase exposure to the toxicant.
      PubDate: 2016-04-21T06:50:22.403982-05:
      DOI: 10.1002/ps.4294
       
  • Non‐target‐site glyphosate resistance in Conyza bonariensis is
           based on modified subcellular distribution of the herbicide
    • Authors: Ziv Kleinman; Baruch Rubin
      Abstract: BACKGROUND Conyza spp. was the first broadleaf weed reported to have evolved glyphosate resistance. Several mechanisms have been proposed for glyphosate resistance. In an effort to elucidate the mechanism of this resistance in Conyza bonariensis, possible target‐site and non‐target site mechanisms were investigated in glyphosate‐resistant (GR) C. bonariensis biotypes. RESULTS Using differential glyphosate applications and analyses of shikimate accumulation, we followed the herbicide effect in different plant organs and monitored the herbicide's apparent mobility. We found high shikimate levels in the roots and young leaves of GS plants regardless of the site of application; whereas in GR plants, shikimate accumulated mainly in treated young leaves. 14C‐glyphosate studies, however, revealed the expected source‐to‐sink translocation pattern in both GS and GR plants. Sequencing of the appropriate EPSPS DNA fragments of GR and glyphosate‐sensitive (GS) plants revealed no alteration at the Pro106 position. CONCLUSION These data support the hypothesis that the glyphosate resistance of our Conyza bonariensis GR biotypes is associated with altered subcellular distribution of glyphosate, which keeps the herbicide sequestered away from the EPSPS target site in the chloroplast.
      PubDate: 2016-04-21T06:45:23.281578-05:
      DOI: 10.1002/ps.4293
       
  • Landscape crop composition effects on cotton yield, Lygus hesperus
           densities, and pesticide use
    • Authors: Matthew H. Meisner; Tania Zaviezo, Jay A. Rosenheim
      Abstract: BACKGROUND Landscape crop composition surrounding agricultural fields is known to affect the density of crop pests, but quantifying these effects, as well as measuring how they translate to changes in yield, is difficult. Using a large dataset consisting of 1498 records of commercial cotton production in California between 1997 and 2008, we explored the relationship between landscape composition and cotton yield, the density of Lygus hesperus (a key cotton pest) at field‐level and within‐field spatial scales, and pesticide use. RESULTS We found that the crop composition immediately adjacent to a cotton field was associated with substantial differences in cotton yield, L. hesperus density, and pesticide use. Furthermore, crops that tended to be associated with increased L. hesperus density also tended to be associated with increased pesticide use and decreased cotton yield. CONCLUSION Our results suggest a possible mechanism by which landscape composition can affect cotton yield: by increasing the density of pests that in turn damage cotton plants. Our quantification of how surrounding crops affect pest densities, and in turn yield, in cotton fields, has significant impacts for cotton farmers who can use this information to help optimize crop selection and ranch layout.
      PubDate: 2016-04-10T22:35:23.986891-05:
      DOI: 10.1002/ps.4290
       
  • Effect of three safeners on sulfur assimilation and iron deficiency
           response in barley (Hordeum vulgare) plants
    • Authors: Maria Luce Bartucca; Silvia Celletti, Stefania Astolfi, Tanja Mimmo, Stefano Cesco, Ivan Panfili, Daniele Del Buono
      Abstract: BACKGROUND Safeners are agrochemicals used in agriculture to protect crop from herbicide injuries. They act by stimulating herbicide metabolism. Since graminaceous plants to cope with iron (Fe) deficiency activate sulfur (S) metabolism and release huge amounts of Fe chelating compounds (phytosiderophores – PSs), we investigated in barley plants (Hordeum vulgare, L.) grown in Fe‐deficiency the effects of three safeners on two enzymes of S assimilation, cysteine (Cys) and glutathione (GSH) contents, and PSs release. Finally, we monitored the root Fe content in plants treated with the most effective safener. RESULTS Generally, all the safeners activated S metabolism and increased Cys and GSH contents. In addition, the safened plants excreted higher levels of PSs. Being mefenpyr‐diethyl (Mef) the most effective in causing these effects, we assessed Fe concentration in Mef treated barley and we found higher Fe levels than those of untreated plants. CONCLUSION The three safeners differently, but specifically, activated S reductive metabolism, regulated Cys and GSH contents, PSs rate release and Fe content (Mef treated barley). The results of this research provide new indications on the biochemical and physiological mechanisms involved in the safening action.
      PubDate: 2016-04-08T13:09:21.844325-05:
      DOI: 10.1002/ps.4291
       
  • Postharvest impacts of rodents in Myanmar; how much rice do they eat and
           damage?
    • Authors: Nyo Me Htwe; Grant R Singleton, Pyai Phyo Maw
      Abstract: BACKGROUND We undertook studies on postharvest losses by rodents in two townships in the Ayeyarwady delta, Myanmar. Farmers harvest their monsoon rice crop and then stack it on levee banks to await threshing 4–6 weeks later. After threshing and drying, paddy rice is stored in granaries. The amount of grain stored in burrows was collected 4 weeks after harvest by excavating burrows. In grain stores, we quantified weight of grain consumed by rodents for 3–6 months postharvest. RESULTS The dominant species in the field were Bandicota bengalensis and B. indica, whereas in grain stores the dominant species were Rattus rattus and R. exulans. The mean grain stored by rodents in burrows was 1.49 ± 0.9 kg/ burrow in 2013 and 1.41 ± 0.7 kg/ burrow in 2014. The mean loss of grain in granaries was higher in Daik U (14% in 2013, 4% in 2014) than Maubin (8.2% in 2013, 1.2% in 2014). The total amount of grain lost to rodents during piling and storing could feed households from 1.6‐4 months. CONCLUSION Postharvest losses to grain is a significant food security issue for smallholder farmers in Myanmar. Community rodent management and better rodent proofing of granaries are recommended to reduce rodent losses.
      PubDate: 2016-04-08T13:08:28.601908-05:
      DOI: 10.1002/ps.4292
       
  • Lures for Red Palm Weevil trapping systems: aggregation pheromone and
           synthetic kairomone
    • Abstract: BACKGROUND The optimization of the lure is essential for the implementation of trapping systems to control insect pests. In this work, the response of the red palm weevil (RPW), Rhynchophorus ferrugineus Olivier, to increasing emission rates of its aggregation pheromone (ferrugineol) and the efficacy of a convenient synthetic kairomone based on fermentation odors (ethyl acetate and ethanol) have been evaluated in different years and locations along the Mediterranean basin. RESULTS In general, although capture data and emission had noticeable variability among locations, significantly less RPW were captured in pyramidal Picusan® traps with the lowest ferrugineol emission rates tested (0.6‐3.8 mg/day−1). Captures increase rapidly with ferrugineol emission up to 4–5 mg day−1; then, higher emission rates did not improve nor decrease captures, up to the highest emission rate tested of 50.9 mg day−1. Thus, there is no evidence of an optimum release rate corresponding with a maximum of RPW catches. Traps baited with the synthetic kairomone (1:3 ethyl acetate/ethanol) captured from 1.4 to 2.2 times more total weevils than traps baited only with ferrugineol. Moreover, in most of the locations, the synthetic blend was at least as effective as the local co‐attractants used (plant material + molasses). CONCLUSIONS Ferrugineol emission rate can vary in a wide range without affecting significantly RPW response. Co‐attractants based on fermenting compounds, ethyl acetate and ethanol, are able to improve the attractant level of ferrugineol and could be employed to replace non‐standardized natural kairomones in RPW trapping systems after further optimization of their proportions and doses.
      PubDate: 2016-04-06T03:19:10.334186-05:
      DOI: 10.1002/ps.4289
       
  • Two compounds in bed bug feces are sufficient to elicit off‐host
           aggregation by bed bugs, Cimex lectularius
    • Authors: Joelle F. Olson; Leonard M. Ver Vers, Roger D. Moon, Stephen A. Kells
      Abstract: BACKGROUND After feeding, bed bugs aggregate in cracks and crevices near a host. Aggregation and arrestment are mediated by tactile and chemical stimuli associated with the bugs’ feces and exuviae. Volatiles derived from fecally stained filter papers were analyzed by SPME and evaluated using a multi‐choice behavioral assay to determine their impact on bed bug aggregation. In addition, crude fecal extracts were collected in methanol, analyzed by GC‐EAD and GC‐MS and evaluated in open‐air multiple choice behavioral assays. RESULTS An SPME method was used to detect (E)‐2‐hexenal and (E)‐2‐octenal in heated bed bug feces. The presence of these two volatile components did not affect aggregation. Analysis of the crude fecal extracts revealed several semi‐volatile nitrogenous compounds, a carboxylic acid, and a sulfur based compound. Adult antennae responded to compounds eluted from three regions of the crude extract using GC‐EAD. A combination of two compounds, dimethyl trisulfide (DMTS) and methyldiethanolamine (MDEA) resulted in aggregation responses equivalent to original crude extract. CONCLUSION Bed bug aggregation is mediated by semi‐volatile compounds derived from fecal extracts, and two compounds are sufficient to elicit aggregation. The two compounds identified here could be used to enhance the effectiveness of insecticidal applications or improve monitoring techniques.
      PubDate: 2016-04-06T02:52:55.892661-05:
      DOI: 10.1002/ps.4286
       
  • Knockdown of two trehalose‐6‐phosphate synthases severely
           affects chitin metabolism gene expression in the brown planthopper
           Nilaparvata lugens
    • Abstract: BACKGROUND RNA interference combined with digital gene expression (DGE) analysis can be used to study gene function. Trehalose‐6‐phosphate synthase (TPS) plays a key role in the synthesis of trehalose and insect development. RESULTS The DGE analysis revealed that the expression of 9 or 4 chitinase genes was decreased significantly 48 h after NLTPS1 and NLTPS2 knockdown by RNAi, respectively. Additionally, abnormal phenotypes were noted, and approximately 30% of insects died. HK and G6PI2 expression decreased significantly 72 h, whereas GFAT, GNPNA, and UAP expression increased significantly 72 h after two NLTPS genes RNAi knockdown. PGM1 expression decreased significantly after TPS2 knockdown, whereas PGM2 expression increased significantly and the expression of three CHS genes decreased 48 h after TPS1 knockdown. The mRNA expression of all of twelve chitin degradation genes decreased 48 h after NLTPS1 and NLTPS2 RNAi treatment, and Cht2, Cht3, Cht6, Cht7, Cht10, and ENGase levels remained significantly decreased up to 72 h after NLTPS1 and NLTPS2 RNAi knockdown. CONCLUSIONS These results demonstrate that silencing of TPS genes can lead to increased molting deformities and mortality rates due to the misregulation of genes involved in chitin metabolism, and TPS genes are potential pest control targets in the future.
      PubDate: 2016-04-06T02:51:47.088151-05:
      DOI: 10.1002/ps.4287
       
  • Evaluation of chromatic cue for trapping Bactrocera tau
    • Authors: Lei Li; Huabo Ma, Liming Niu, Dongyin Han, Fangping Zhang, Junyu Chen, Yueguan Fu
      Abstract: BACKGROUND Trapping technology based on chromatic cues is an important strategy in controlling Tephritidae (fruit flies). The objectives of this present study were to evaluate the preference of Bactrocera tau to different chromatic cues and to explore an easy method to print and reproduce color paper. RESULTS Chromatic cues significantly affected the preference of adult B. tau. The wavelengths in the range of 515 to 604 nm were the suitable wavelengths for trapping B. tau. Different day‐old B. tau had different color preferences. Virtual wavelengths of 595 (yellow) and 568 nm (yellowish green) were the optimum wavelengths for trapping 5‐day‐old to 7‐day‐old B. tau and 30‐day‐old to 32‐day‐old B. tau, respectively. The trap type and height significantly influenced the attraction efficiency of B. tau. The number of B. tau on color traps hung perpendicular to plant rows were not significantly higher than those hung parallel to plant rows. CONCLUSION The quantization of color on the basis of Bruton's wavelength to RGB function can be served as an alternative method to print and reproduce the color papers, but a corrected equation should be established between the theoretical wavelength and actual wavelength of color papers. Results show that a compound paper colored yellow (595 nm) and yellowish green (568 nm) installed at 60 and 90 cm in height above the ground show the maximum effect for trapping B. tau.
      PubDate: 2016-04-06T02:49:50.114541-05:
      DOI: 10.1002/ps.4288
       
  • Pesticide exposure assessment for surface waters in the EU ‐ Part 1:
           Some comments on the current procedure
    • Abstract: BACKGROUND In 2001, the European Commission introduced a risk assessment project known as FOCUS (FOrum for the Co‐ordination of pesticide fate models and their USse) for the surface water risk assessment of active substances in the European Union. Even for the national authorisation of plant protection products (PPP) the vast majority of EU Member States still refer to the four runoff and six drainage scenarios selected by the FOCUS Surface Water Workgroup. However, our study as well as the European Food Safety Authority (EFSA) has stated the need for various improvements. RESULTS Current developments in pesticide exposure assessment mainly relate to two processes: first, predicted environmental concentrations (PECs) of pesticides are calculated by introducing model input variables such as weather conditions, soil properties and substance fate parameters that have a probabilistic nature. Second, spatially distributed PECs for soil‐climate scenarios are derived based on an analysis of geodata. Such approaches facilitate the calculation of a spatio‐temporal cumulative distribution function (CDF) of PECs for a given area of interest and are subsequently used to determine an exposure concentration endpoint as a given percentile of the CDF. CONCLUSION For national PPP authorisation, we propose that in the future, exposure endpoints should be determined from the overall known statistical PEC population for an area of interest, and derived for soil and climate conditions specific to the particular Member State.
      PubDate: 2016-04-05T06:22:51.878168-05:
      DOI: 10.1002/ps.4281
       
  • Trypsin inhibitor from Leucaena leucocephala seeds delays and disrupts the
           development of Aedes aegypti, a multiple disease vector
    • Abstract: BACKGROUND Nowadays Aedes aegypti mosquito represents a serious issue in public health due to the large outbreaks of the arboviral diseases Zika, Dengue, Chikungunya and Yellow fever. This holometabolous insect has midgut digestive enzymes which are trypsin and chymotrypsin‐like proteins. Protease inhibitors are able to bind to proteolytic enzymes and promote a blockage in digestion and nutrition leading to death. Thus, we investigated the effect of trypsin inhibitor of Leucaena leucocephala (LTI) seeds upon egg hatching, larval development and digestive midgut proteases. RESULTS LTI was obtained by TCA‐precipitation followed by a single chromatography step on anhydrous trypsin sepharose. SDS‐PAGE showed a single protein band with molecular mass near 20 kDa. After exposure of Ae. aegypti egg to LTI (0.3 mg.mL−1), egg hatching was reduced (50%). LTI did not show acute toxicity on newly hatched larvae incubated under the same conditions, but after ten days of exposure a high mortality rate (86%) was observed and the surviving larvae had a 25% delay in development. LTI was able to inhibit in vitro the midgut enzymatic activity (70%) and when larvae were incubated with LTI solution we observed an inhibition of 56%. CONCLUSIONS LTI is a promising new tool to control critical points of Ae. aegypti development.
      PubDate: 2016-04-04T06:29:03.104057-05:
      DOI: 10.1002/ps.4284
       
  • The mononuclear NiII complex
           bis(azido‐κN)bis[2,5‐bis(pyridin‐2‐yl)‐1,3,4‐thiadiazole‐κ2N2,N3]nickel(II)
           protects tomato from Verticillium dahliae by inhibiting the fungal growth
           and activating plant defenses
    • Authors: Hanane Zine; Lalla Aicha Rifai, Tayeb Koussa, Fouad Bentiss, Salaheddine Guesmi, Abdelhakim Laachir, Kacem Makroum, Malika Belfaiza, Mohamed Faize
      Abstract: BACKGROUND The antifungal proprieties of the nickel complex bis(azido‐κN)bis[2,5‐bis(pyridin‐2‐yl)‐1,3,4‐thiadiazole‐κ2N2,N3]nickel(II) (noted NiL2(N3)2) and its parental ligand 2,5‐bis(pyridin‐2‐yl)‐1,3,4‐thiadiazole (L) were examined to evaluate their ability to protect tomato plants against Verticillium dahliae. Our main objectives were to determine their effects on the in vitro growth of the pathogen, and their aptitude on controlling verticillium wilt and activating plant defense responses in the greenhouse. RESULTS NiL2(N3)2 exhibited in vitro an elevated inhibition of radial growth of three strains of the pathogen. According to the strain, the EC50 values ranged from 10 to 29 µg ml−1 for NiL2(N3)2. In the greenhouse, it induced an elevated protection against V. dahliae when it was applied twice as foliar sprays at 50 µg ml−1. It reduced leaf alteration index by 85% and vessel browning by 96%. In addition, its protective ability was associated with the accumulation of H2O2, and the activation of total phenolic content as well as potentiation of the activity of peroxidase and polyphenol oxidase. CONCLUSION These results demonstrated that coordination of ligand with Ni associated to the azide as a co‐ligand resulted in the improvement of its biological activity by both inhibiting the growth of the V. dahliae and activating plant defense responses.
      PubDate: 2016-04-04T06:27:38.017174-05:
      DOI: 10.1002/ps.4285
       
  • Impact of Bacillus cereus NRKT on grape ripe rot disease through
           resveratrol synthesis in berry skin
    • Authors: Takanori Aoki; Yoshinao Aoki, Shiho Ishiai, Misa Otoguro, Shunji Suzuki
      Abstract: BACKGROUND Vine growers are faced with the difficult problem of how to control grape ripe rot disease in vineyards because of fear of accumulation of pesticide residues on grape berries near harvest. Biological control is an alternative non‐hazardous technique to control the diseases. RESULTS Application of resveratrol‐synthesis‐promoting bacterium, Bacillus cereus strain NRKT, decreased the incidence of grape ripe rot disease caused by Colletotrichum gloeosporioides in a vineyard. The application of NRKT to berry bunches upregulated the gene expression of stilbene synthase, a key enzyme for resveratrol synthesis in berry skins, thereby promoting resveratrol synthesis in berry skins. CONCLUSION The potential use of NRKT in vineyards is expected to contribute to the increase of resveratrol content in berry skins, thereby protecting grape berries against fungal diseases.
      PubDate: 2016-04-01T00:12:10.405601-05:
      DOI: 10.1002/ps.4283
       
  • Migration by seed dispersal of ACCase inhibitor resistant Avena fatua in
           Northwestern Mexico
    • Abstract: BACKGROUND Biotypes of Avena fatua resistant to ACCase‐inhibiting herbicides have been reported in the States of Baja California (BC) and Sonora (SON), Mexico. We hypothesized that resistant biotypes present in SON (Valle de Hermosillo and Valle del Yaqui) are derived from a resistant population from BC (Valle de Mexicali) via gene flow, due to the transport and exchange of contaminated wheat seed. This study aimed to determine: 1) the resistance of A. fatua to ACCase‐inhibiting herbicides in populations from BC and SON, 2) the mutation at the site of action and 3) the genetic structure and gene flow among populations. RESULTS DNA sequencing showed that all biotypes shared the same mutation (Leu x Ile at codon 1781). Microsatellites showed evidence of a genetic bottleneck in SON, and spatial analysis of molecular variance grouped one biotype from the Valle de Mexicali with two biotypes from the Valle de Hermosillo. Migration analysis suggested gene flow from the Valle de Mexicali to the Valle de Hermosillo, but not to the Valle del Yaqui. CONCLUSIONS The presence of resistant biotypes of Avena fatua in the Valle de Hermosillo, SON are likely derived from seeds from BC, possibly through the transport of contaminated wheat seeds.
      PubDate: 2016-04-01T00:11:55.39262-05:0
      DOI: 10.1002/ps.4282
       
  • Distinguishing between weedy Amaranthus species based on intron one
           sequences from the 5‐enolpyruvylshikimate‐3‐phosphate
           synthase (EPSPS) gene
    • Authors: Alice A. Wright; William T. Molin, Vijay K. Nandula
      Abstract: BACKGROUND Hybridization between Amaranthus species and the potential for herbicide resistance to be transferred by hybridization are of growing concern in the weed science community. Early detection of evolved herbicide resistance and hybrids expressing resistance to single or multiple herbicides is important to develop an effective control strategy. RESULTS A PCR test was developed to quickly identify weedy amaranths and any hybrids. The sequences of intron one for the 5‐enolpyruvylshikimate‐3‐phosphate synthase (EPSPS; EC 2.5.1.19) gene were determined for Amaranthus palmeri, A. retroflexus, A. blitoides, A. viridis, A. tuberculatus, and A. hybridus. These sequences were aligned and primers were developed in areas where the sequence differed between species. Species specific primers and cycle conditions were successfully developed. These primers produce a single robust band only for the species for which they were designed. CONCLUSION The PCR techniques described here allow identification of a weedy amaranth or suspect hybrid in a few hours. Using a similar target, it may be possible to design similar, simple PCR tests to identify even more difficult to distinguish weed species or weeds prone to interspecific hybridization.
      PubDate: 2016-03-23T01:30:50.477582-05:
      DOI: 10.1002/ps.4280
       
  • Evaluation of Spray Application Methods for Navel Orangeworm Control in
           Almonds
    • Authors: James C. Markle; Franz J. Niederholzer, Frank G. Zalom
      Abstract: BACKGROUND Gear Up, Throttle Down (GUTD) and Inward Only strategies represent potential alternatives to conventional airblast applications to reduce spray drift. This study evaluates Inward Only and a modified version of GUTD in almonds, the largest U.S. tree crop, at the recommended hull split treatment timing for control of navel orangeworm (NOW), the key almond insect pest. RESULTS Conventional treatment produced the most drift (15.6% of total bifenthrin load) while the GUTD and Inward Only treatments produced only 7.6% and 9.7%, respectively. For all methods 92‐94% of the drift was found in the first 15.2 m downwind of the orchard. NOW control was lower for the Inward Only treatment compared with the GUTD and Conventional treatments. NOW control was consistently lower at the 4.88 m height relative to 2.44 m in all treatments, reflecting the reduced deposition higher in the tree canopy recorded in deposition samples. CONCLUSION While Inward Only treatments reduced spray drift relative to the Conventional application method, poorer control of NOW, the key insect pest of almonds, in the Inward Only treatment would likely limit its voluntary use by growers. However, GUTD holds promise for use at the hull split treatment timing to address spray drift.
      PubDate: 2016-03-22T03:50:23.073853-05:
      DOI: 10.1002/ps.4279
       
  • Accurate prediction of black‐rot epidemics in vineyards using a
           weather‐driven disease model
    • Abstract: Background Grapevine black‐rot caused by Guignardia bidwellii is a serious threat in vineyards, especially in areas with cool and humid springs. A mechanistic, weather‐driven model was recently developed for the detailed prediction of black‐rot epidemics. The aim of this work was the evaluation of the model by comparison with observed disease development in leaves and clusters in a vineyard in north Italy from 2013 to 2015. Results The model accurately predicted disease onset. The probability of predicting new infections that did not occur (i.e., unjustified alarms) was ≤ 0.180, while the probability of missing actual infections was 0.175 for leaves and 0.263 for clusters. In 78% of these false negative predictions, the difference between expected and actual disease onset was ± 2 days; therefore, only one infection period was actually missed by the model. The model slightly overestimated disease severity (mainly on leaves) when the observed disease severity was >0.6. Conclusions The model was highly accurate and robust in predicting the infection periods and dynamics of black‐rot epidemics. The model can be used for scheduling fungicide sprays in vineyards.
      PubDate: 2016-03-21T02:45:25.232311-05:
      DOI: 10.1002/ps.4277
       
  • Phenotypical and biochemical characterization of resistance for parasitic
           weed (Orobanche foetida Poir.) in radiation mutagenized mutants of
           chickpea
    • Authors: Ines Brahmi; Yassine Mabrouk, Guillaume Brun, Philippe Delavault, Omrane Belhadj, Philippe Simier
      Abstract: BACKGROUND Some radiation mutagenized chickpea mutants potentially resistant to the broomrape, Orobanche foetida Poir., were selected through field trials. The objectives of this work were to confirm resistance under artificial infestation, in pots and mini‐rhizotron systems, and to determine the developmental stages of broomrape affected by resistance and the relevant resistance mechanisms induced by radiation mutagenesis. RESULTS Among thirty mutants tested for resistance to O. foetida, five shared strong resistance in both pot experiments and mini‐rhizotrons systems. Resistance was not complete but the few individuals which escaped resistance displayed high disorders of shoot development. Results demonstrated a 2–3 fold decrease in stimulatory activity of root exudates towards broomrape seed germination in resistant mutants in comparison to non‐irradiated control plants and susceptible mutants. Resistance was associated to an induction of broomrape necrosis early during infection. When infested, most of resistant mutants shared enhanced levels in soluble phenolic contents, phenylalanine ammonia lyase activity, guaiacol peroxidase activity, polyphenol oxidase activity, in addition to glutathione and notably ascorbate peroxidase gene expression in roots. CONCLUSION Results confirmed enhanced resistance in chickpea radiation mutagenized mutants, and demonstrated resistance is rested on alteration of root exudation, presumed cell wall reinforcement and change in root oxidative status in response to infection.
      PubDate: 2016-03-21T02:45:22.563375-05:
      DOI: 10.1002/ps.4278
       
  • Genetic variation in target‐site resistance to pyrethroids and
           pirimicarb in Tunisian populations of the peach potato aphid, Myzus
           persicae (Sulzer) (Hemiptera: Aphididae)
    • Abstract: BACKGROUND We used molecular assays to diagnose resistance to pyrethroids and pirimicarb in samples of Myzus persicae from field crops or an insect suction trap in Tunisia. Genotypes for resistance loci were related to ones for polymorphic microsatellite loci in order to investigate breeding systems, patterns of genetic diversity and to inform resistance management tactics. RESULTS The kdr mutation L1014F conferring pyrethroid resistance was found in all samples. The M918T s‐kdr mutation also occurred in most samples, but only in conjunction with kdr. We discovered a previously unreported genotype heterozygous for L1014F but homozygous for M918T. Samples with modified acetylcholinesterase (MACE) conferring resistance to pirimicarb were less common but widespread. 16% of samples contained both the kdr and MACE mutations. Many unique microsatellite genotypes were found, suggesting that M. persicae is holocyclic in Tunisia. There were no consistent associations between resistance and microsatellite markers. CONCLUSION This first study of insecticide resistance in M. persicae in North Africa showed genetic variation in insecticide resistance within microsatellite multilocus genotypes (MLGMs) and the same resistance mechanisms to be present in different MLGMs. This contrasts with variation in northern Europe where M. persicae is fully anholocyclic. Implications for selection and control strategies are discussed.
      PubDate: 2016-03-16T03:16:28.066508-05:
      DOI: 10.1002/ps.4276
       
  • Increasing social welfare by taxing pesticide externalities in the Indian
           cotton sector
    • Authors: Livia Rasche; Alexander Dietl, Nikolinka Shakhramanyan, Divya Pandey, Uwe A. Schneider
      Abstract: Background Pesticide use in the Indian cotton industry has decreased with the introduction of Bt cotton, but rates are still high in comparison to other countries. The adoption of alternative strategies, such as integrated pest management, has been slow, even though benefits are potentially high, more so if the full costs of the external effects of the technologies are taken into account. In order to estimate true societal benefits of different strategies, we compare their external costs and economic performance under external cost taxation, using a state of the art partial equilibrium model of the Indian agricultural sector. Results Pesticide externalities lower social welfare in the Indian cotton sector by USD 400–2200 million, depending on the technologies employed. A full internalization decreases producer revenues by 100 USD/ha if only Bt cotton is used, and by 30 USD/ha if IPM is another option. Consumers don't start to lose surplus until 20‐70% are internalized, and losses are smaller if all technologies are available. Conclusions External pesticide costs can be internalized partially without substantially impacting consumer surplus while still increasing social welfare, but producers need to have access to and the knowledge to employ all available cotton production technologies to minimize losses.
      PubDate: 2016-03-15T06:41:54.747232-05:
      DOI: 10.1002/ps.4275
       
  • Frequency of Cry1F Resistance Alleles in Spodoptera frugiperda
           (Lepidoptera: Noctuidae) in Brazil
    • Authors: Juliano R Farias; David A. Andow, Renato J Horikoshi, Daniel Bernardi, Rebeca da S Ribeiro, Antonio R B do Nascimento, Antonio C dos Santos, Celso Omoto
      Abstract: BACKGROUND The frequency of resistance alleles is a major factor influencing the rate of resistance evolution. Here, we adapted the F2 screen procedure for Spodoptera frugiperda (J.E. Smith) with a discriminating concentration assay, and extended associated statistical methods to estimate the frequency of resistance to Cry1F protein in S. frugiperda in Brazil when resistance was not rare. RESULTS We show that F2 screen is efficient even when resistance frequency is 0.250. It was possible to screen 517 isoparental lines from 12 populations sampled in five states of Brazil during the first half of 2012. Western Bahia had the highest allele frequency of Cry1F resistance, 0.192, with a 95% confidence interval (CI) between 0.163 and 0.220. All other states had a similar and lower frequency varying from 0.042 in Paraná to 0.080 in Mato Grosso do Sul. CONCLUSION The high frequency in western Bahia may be related to year‐round availability of maize, the high population density of S. frugiperda, the lack of refuges, and the high adoption rate of Cry1F maize. Cry1F resistance alleles were not rare and occurred at frequencies that have already compromised the useful life of TC1507 maize in western Bahia.
      PubDate: 2016-03-15T05:51:16.334391-05:
      DOI: 10.1002/ps.4274
       
  • Movement and survival of Busseola fusca (Lepidoptera: Noctuidae) larvae
           within maize plantings with different ratios of non‐Bt and Bt seed
    • Authors: Annemie Erasmus; Jaco Marais, Johnnie Van den Berg
      Abstract: BACKGROUND Products of plant biotechnology, for example genetically modified Bt maize, provide useful tools for pest management. The benefits provided by insect resistant plants are, however, threatened by the evolution of resistance by target pest species. The high‐dose/refuge insect resistance management strategy (IRM) as well as seed mixtures are globally used as IRM strategies. Busseola fusca (Lepidoptera: Noctuidae), the target stem borer of Bt maize in Africa, evolved resistance to Bt maize expressing Cry1Ab protein in South Africa. Due to high larval mobility and subsequent sub‐lethal exposure of larvae moving between non‐Bt and Bt plants, more rapid resistance evolution has been proposed as a possibility with deployment of seed mixture strategies. RESULTS Laboratory and field studies were conducted to study B. fusca larval mobility. In the laboratory different scenarios of B. fusca larval movement between single gene (Cry1Ab) and stacked trait (Cry1A.105 and Cry2Ab2) Bt maize was studied. Data on larval survival and mass over time indicated that Cry proteins do not kill larvae above certain developmental stages. A 2‐year field study with the single‐gene and the stacked event was conducted using seed mixtures containing 5, 10, 15 and 20% non‐Bt seed as well as a control treatment (non‐Bt seed only). CONCLUSION Larval movement continued for five weeks and resulted in a significant incidence of Bt and non‐Bt damaged plants, indicating that the movement behaviour of B. fusca is of such a nature that seed mixtures as an IRM strategy may not be effective to delay resistance evolution.
      PubDate: 2016-03-15T05:51:10.19927-05:0
      DOI: 10.1002/ps.4273
       
  • Reducing the availability of food to control feral pigeons: changes in
           population size and composition
    • Abstract: BACKGROUND Since feeding by humans is one of the main food resources to pigeons (Columba livia), there is general agreement that public education that aims to reduce the food base may be the most feasible way to reduce pigeon abundance. However, except for the classic example of Basel, the method has rarely been tested or implemented. We provide results from a one‐year study in the city of Barcelona where we tested the effect of public education on pigeon population abundance and composition. RESULTS The quantity of food provided by people to pigeons was significantly reduced during the study. Feral pigeon density was reduced by 40% in the two experimental districts, but no variation was detected in the control district. Detailed analyses in one of the districts showed that the reduction was mainly related to the reduction in food availability but not to culling. Pigeons captured at the end of the experiment were larger than at the start of the study but body condition was reduced. CONCLUSION Results show the effectiveness of public information to manage feral pigeon populations in a large city and that control operations can exert important selection pressure on the population leading to changes in population composition.
      PubDate: 2016-03-07T00:30:54.913533-05:
      DOI: 10.1002/ps.4272
       
  • Simplified strigolactams as potent analogues of strigolactones for the
           seed germination induction of Orobanche cumana Wallr
    • Abstract: Background Strigolactones play an important role in the rhizosphere as signaling molecules stimulating the seed germination of parasitic weed seeds and hyphal branching of arbuscular micorrhiza and also act as hormones in plant roots and shoots. Strigolactone derivatives e.g. strigolactams could be used as suicidal germination inducers in the absence of a host crop for the decontamination of land infested with parasitic weed seeds. Results We report the stereoselective synthesis of novel strigolactams together with some of their critical physicochemical properties such as water solubility, hydrolytic stability, as well as their short soil persistence. In addition, we show that such strigolactams are potent germination stimulants of O. cumana parasitic weed seeds and do not affect the seed germination and the root growth of sunflower. Conclusions The novel strigolactam derivatives described here compare favorably with the corresponding GR‐28 strigolactones in term of biological activity and physicochemical properties. However, we believe strigolactone‐ and strigolactam‐ derivatives require further structural optimization to improve their soil persistence to demonstrate a potential for agronomical applications.
      PubDate: 2016-03-04T03:44:40.053989-05:
      DOI: 10.1002/ps.4268
       
  • Detection of Zymoseptoria tritici SDHI insensitive field isolates carrying
           the SdhC‐H152R and SdhD‐R47W substitutions
    • Abstract: BACKGROUND Succinate dehydrogenase inhibitor fungicides are important in the management of Zymoseptoria tritici in wheat. New active ingredients from this group of fungicides have been introduced recently and are widely used. Because the fungicides act at a single enzyme site, resistance development in Z. tritici is classified as medium‐to‐high risk. RESULTS Isolates from Irish experimental plots in 2015 were tested against the SDHI penthiopyrad during routine monitoring. The median of the population was approximately 2 x less sensitive than the median of the baseline population. Two of the 93 isolates were much less sensitive to penthiopyrad than the least sensitive of the baseline isolates. These isolates were also insensitive to most commercially available SDHIs. Analysis of the succinate dehydrogenase coding genes confirmed the presence of the substitutions SdhC‐H152R and SdhD‐R47W in the very insensitive isolates. CONCLUSION This is the first report showing that the SdhC‐H152R mutation detected in laboratory mutagenesis studies also exist in the field. The function and relevance of this mutation, combined with SdhD‐R47W, still needs to be determined.
      PubDate: 2016-03-04T03:44:29.807034-05:
      DOI: 10.1002/ps.4269
       
  • A historical perspective on the effects of trapping and controlling the
           muskrat (Ondatra zibethicus) in The Netherlands
    • Authors: E. Emiel van Loon; Daan Bos, Caspara.J. van Hellenberg Hubar, Ron C. Ydenberg
      Abstract: BACKGROUND Muskrat are considered a pest species in The Netherlands, and a year‐round control programme is in effect. We aimed to evaluate the effectiveness of this programme using historical data on catch and effort collected at a provincial scale. RESULTS The development of the catch differed between provinces, depending on the year of colonisation by muskrat and the investment of effort (measured as field hours). The catch did not peak in the same year for the various provinces, and provinces that were colonized earlier in time took longer to attain the peak catch. Trapping resulted in declining populations, but only after a certain threshold of annual effort in trapping had been surpassed. On average populations were observed to decline when the annual effort exceeded 1.4 field hour per km of waterway for several successive years. After having reached a phase of greater control, control organizations tended to reduce effort. CONCLUSION We conclude that control measures can make muskrat populations decline, provided that the effort is commensurate with the population size. Our study emphasizes that experimentation is needed to confirm the causality of the findings, to establish the relation with damage or safety risk and to derive an optimal control strategy.
      PubDate: 2016-03-04T03:44:25.908234-05:
      DOI: 10.1002/ps.4270
       
  • Sublethal effects of chlorantraniliprole on development, reproduction, and
           vitellogenin gene (CsVg) expression in the rice stem borer, Chilo
           suppressalis
    • Authors: Li Huang; Mingxing Lu, Guangjie Han, Yuzhou Du, Jianjun Wang
      Abstract: BACKGROUND The rice stem borer, Chilo suppressalis (Walker), is one of the most damaging rice pests in the world. The sublethal effects of chlorantraniliprole on development,reproduction, and mRNA expression levels of vitellogenin gene (CsVg) in C. suppressalis were investigated. RESULTS Exposure of sublethal concentrations of chlorantraniliprole (LC10 and LC30) to the third instar larvae significantly extended larvae duration, lowered mean weight of male pupae, and shortened male adult longevity. The pupae duration was significantly prolonged and the mean weight of female pupae was significantly lowered in treatment group of LC30. While there were no significant sublethal effects on either the adult emergence rate or the egg hatch, the pupation rates in treatment groups of LC10 (41.30%) and LC30 (23.98%) were significantly lower than that of the control (71.86%), and the LC10 and LC30 chlorantraniliprole significantly decreased fecundity by 32.18% and 52.94%, respectively. Furthermore, the expression levels of CsVg mRNA after exposure to LC10 and LC30 chlorantraniliprole significantly decreased by 42.52% and 47.84%, respectively, in 12‐h‐old female adults. CONCLUSION Sublethal concentrations of chlorantraniliprole adversely affect the development and reproduction of C. suppressalis. The down‐regulation of CsVg by chlorantraniliprole might have negative impacts on the fecundity of C. suppressalis.
      PubDate: 2016-03-04T03:44:18.144773-05:
      DOI: 10.1002/ps.4271
       
  • Eradication of Common Mynas Acridotheres tristis from Denis Island,
           Seychelles
    • Abstract: BACKGROUND In Seychelles the Common Myna has been shown to negatively impact endangered endemic birds, on Denis Island interfering with breeding attempts and attacking adult endemic birds at their nests. This stimulated an attempt to eradicate the island's mynas. RESULTS The eradication was undertaken in three phases, overall killing 1179 mynas and lasting 4 years. Decoy trapping was the most effective method of catching mynas but the last birds were shot. Decoy trapping was compromised by catches of non‐target species. Data collection from killed birds indicated that trapping did not favour either sex, and that most breeding occurred during the wetter season, November to March. CONCLUSIONS Eradication of mynas from small tropical islands is feasible. The Denis Island eradication was prolonged by difficulties in management and staffing. Using volunteers, the cost of the eradication was similar to that of eradicating rodents from the island. In future eradication attempts in Seychelles, possible food stress during the drier season (May to September) might facilitate trapping at this time. Habitat management, especially the removal of short mown grass, could enhance eradication progress. Continued monitoring is needed to confirm eradication and detect any immigration, and also to record responses in the endemic birds.
      PubDate: 2016-03-03T01:18:19.596826-05:
      DOI: 10.1002/ps.4263
       
  • Chemical modification of phenoxyfuranone‐type strigolactone mimic
           for selective effects on rice tillering or Striga hermonthica seed
           germination
    • Authors: Ikuo Takahashi; Kosuke Fukui, Tadao Asami
      Abstract: BACKGROUND We previously reported that a series of phenoxyfuranone compounds, designated “debranones”, mimic strigolactone (SL) activity. 4‐Bromodebranone (4BD) is a functionally selective SL mimic that reduces the number of shoot branches on rice more potently than GR24, a typical synthetic SL analogue, but does not induce seed germination in the root‐parasitic plant, Striga hermonthica. To enhance the selective activity of debranones in stimulating the seed germination of root‐parasitic plants, we prepared several analogues of 4BD in which the chlorine atom was substituted with an H atom at the o, m, or p position on the phenyl ring (designated 2‐, 3‐, or 4‐chlorodebranone, respectively) or had a bicyclic group instead of the phenyl ring. We evaluated the biological activities of the compounds with rice tillering assays and S. hermonthica seed germination assays. RESULTS Both assays showed that the substituent position affected the debranones’ efficiency, and among the monochlorodebranones, 2‐chlorodebranone was more effective than the other two isomers in both assays. When the activities of the bicyclic debranones were compared in the same two assays, one was more active than GR24 in the rice tillering assay. This debranone also stimulated the germination of S. hermonthica seeds. Thus, some debranone derivatives induced the germination of S. hermonthica seeds, although their activities were still ~1/20 that of GR24. CONCLUSION These results strongly suggest that further and rigorous structure–activity relationship studies of the debranones will identify derivatives that more potently stimulate the suicidal germination of S. hermonthica seeds.
      PubDate: 2016-03-01T01:50:23.190858-05:
      DOI: 10.1002/ps.4265
       
  • A psbA Mutation (Val219 to Ile) Causes Resistance to Propanil and
           Increased Susceptibility to Bentazon in Cyperus difformis
    • Abstract: BACKGROUND Propanil‐resistant (R) Cyperus difformis populations were recently confirmed in California rice fields. To date, propanil resistance in other weed species has been associated with enhanced aryl acylamidase (AAA)‐mediated propanil conversion into 3,4‐dichloroaniline. Our objectives were to determine the level of propanil resistance and cross‐resistance to other PSII inhibitors in C. difformis lines, and to elucidate the mechanism of propanil resistance. RESULTS The propanil‐R line had a 14‐fold propanil resistance and increased resistance to bromoxynil, diuron and metribuzin, but not to atrazine. The R line, however, displayed a four‐fold increased susceptibility to bentazon. Interestingly, S plants accumulated more 3,4‐dichloroaniline and were more injured by propanil and carbaryl (AAA‐inhibitor) applications than R plants, suggesting that propanil metabolism is not the resistance mechanism. psbA gene sequence analysis indicated a valine‐219‐isoleucine (Val219Ile) amino acid exchange in the propanil‐R chloroplast D1 protein. CONCLUSION The D1 Val219Ile modification in C. difformis causes resistance to propanil, diuron, metribuzin, and bromoxynil but increased susceptibility to bentazon, suggesting Val219Ile participates in binding of these herbicides. This is the first report of a higher plant exhibiting target‐site propanil resistance. Tank‐mixing bentazon and propanil, where permitted can control both propanil‐R and –S C. difformis and prevent the spread of the resistant phenotype.
      PubDate: 2016-03-01T01:42:53.820299-05:
      DOI: 10.1002/ps.4267
       
  • Survey of indigenous entomopathogenic fungi and evaluation of their
           pathogenicity against the carmine spider mite, Tetranychus cinnabarinus
           (Boisd.) and the whitefly, Bemisia tabaci (Genn.) biotype B
    • Authors: Emine Topuz; Fedai Erler, Emine Gumrukcu
      Abstract: BACKGROUND The carmine spider mite, Tetranychus cinnabarinus, and silverleaf whitefly, Bemisia tabaci, are serious pests of both field‐ and greenhouse‐grown crops in southwestern Turkey. Control of these pests has been heavily dependent upon chemical pesticides. Objectives of this study were to investigate the occurrence of indigenous entomopathogenic fungi (EPF) in field populations of T. cinnabarinus and B. tabaci, and to evaluate their pathogenicity against these pests. For this purpose, a survey of EPF isolated from field‐collected samples of both pests was carried out in Antalya in 2010 and 2011 using the dilution plating method. RESULTS Four indigenous Beauveria bassiana isolates (TUR1‐B, TUR2‐B, FIN1‐B, FIN2‐B) were recovered. In pathogenicity bioassays with T. cinnabarinus and B. tabaci biotype B, all the isolates tested were pathogenic to some of the biological stages of both pests in varying degrees. FIN1‐B and TUR1‐B caused mortalities of up to 50% and 45%, respectively, in adults of T. cinnabarinus and over 79% and 37%, respectively, in pupae of B. tabaci with 107 conidia mL−1 suspensions under laboratory conditions 10 days after inoculation. FIN2‐B and TUR2‐B had mortalities of 19.45% and 12.28%, respectively, in adults of T. cinnabarinus, and of 6.78% and 8.18%, respectively, in pupae of B. tabaci. All of the isolates had no effect on eggs of both species and larvae of the mite. CONCLUSION Overall results suggest that isolates FIN1‐B and TUR1‐B have potential for management of T. cinnabarinus and B. tabaci.
      PubDate: 2016-03-01T01:42:52.718154-05:
      DOI: 10.1002/ps.4266
       
  • Synthesis and evaluation of hydroxyazolopyrimidines as herbicides; the
           generation of amitrole in planta
    • Authors: John M. Clough; Richard P. Dale, Barry Elsdon, Timothy R. Hawkes, Bridget V. Hogg, Anushka Howell, Daniel P. Kloer, Karine Lecoq, Matthew M. W. McLachlan, Phillip J. Milnes, Timothy J. C. O'Riordan, Saranga Ranasinghe, Stephen E. Shanahan, Karen D. Sumner, Shanaaz Tayab
      Abstract: BACKGROUND Exploiting novel herbicidal modes of action is an important method to overcome the challenges faced by increasing resistance and regulatory pressure on existing commercial herbicides. Recent reports of inhibitors of enzymes in the non‐mevalonate pathway of isoprenoid biosynthesis led to the design of a novel class of azolopyrimidines which were assessed for their herbicidal activity. Studies were also undertaken to determine the mode of action responsible for the observed herbicidal activity. RESULTS In total, 30 novel azolopyrimidines were synthesised and their structures were unambiguously determined by 1H NMR, mass spectroscopy and X‐ray crystallographic analysis. The herbicidal activity of this new chemical class was assessed against six common weed species with compounds from this series displaying bleaching symptomology in post‐emergence tests. A structure‐activity relationship for the novel compounds was determined which showed that only those belonging to the hydroxytriazolopyrimidine sub‐class displayed significant herbicidal activity. Observed similarities between the bleaching symptomology displayed by these herbicides and amitrole suggested that hydroxytriazolopyrimidines could be acting as elaborate pro‐pesticides of amitrole, and this was subsequently demonstrated in plant metabolism studies using Amaranthus retroflexus. It was shown that selected hydroxytriazolopyrimidines which displayed promising herbicidal activity generated amitrole, with peak concentrations of amitrole generally being observed one day after application. Additionally, the herbicidal activity of selected compounds was profiled against tobacco plants engineered to overexpress 4‐diphosphocytidyl‐2C‐methyl‐D‐erythritol synthase (IspD) or lycopene β‐cyclase and the results suggested that, where significant herbicidal activity was observed, inhibition of IspD was not responsible for the activity. Tobacco plants which overexpressed lycopene β‐cyclase showed tolerance to amitrole and the two most herbicidally active triazolopyrimidines. CONCLUSIONS Inhibition of IspD leading to herbicidal activity has been ruled out as the mode of action for the hydroxytriazolopyrimidine class of herbicides. Additionally, tobacco plants which overexpressed lycopene β‐cyclase showed tolerance to amitrole which indicates that this is the main herbicidal mode of action for amitrole. Results from the metabolic fate study of selected hydroxytriazolopyrimidines suggested that the herbicidal activity displayed by these compounds is due to amitrole production, which was confirmed when tobacco plants overexpressing lycopene β‐cyclase also showed tolerance towards two triazolopyrimidines from this study.
      PubDate: 2016-02-26T02:27:52.394714-05:
      DOI: 10.1002/ps.4264
       
  • Clonostachys rosea reduces spot blotch in barley by inhibiting
           pre‐penetration growth and sporulation of Bipolaris sorokiniana
           without inducing resistance
    • Abstract: Background Several diseases threaten cereal production and fungicides are therefore widely used. Biological control is an environmentally friendly alternative and the fungus Clonostachys rosea is a versatile antagonist, effective against several plant diseases. We studied the ability of C. rosea to control barley leaf pathogens and the mechanisms behind the inhibition emphasising induced resistance. Results Under controlled conditions, spray application of C. rosea isolate IK726 to barley leaves reduced Bipolaris sorokiniana severity up to 70% when applied 24 h before or simultaneously as the pathogen, whereas application 24 h after the pathogen had no effect. IK726 also reduced the sporulation capacity of B. sorokiniana. Microscopy of B. sorokiniana infection revealed that IK726 primarily inhibited conidial germination and appressorium formation while further pathogen development and host defence reactions (papillae and fluorescent epidermal cells) were unaffected. Likewise, expression of defence‐related genes encoding PR‐proteins was unaltered. In addition to B. sorokiniana, IK726 also reduced infection by Drechslera teres and Rhynchosporium commune. Conclusion C. rosea acted as a protectant against three barley leaf pathogens. B. sorokiniana was directly inhibited by IK726 whereas induced resistance appeared not to be involved. Quantitative microscopy is a powerful tool for elucidating mechanisms involved in disease control.
      PubDate: 2016-02-23T00:21:19.887168-05:
      DOI: 10.1002/ps.4260
       
  • Fate of insecticidal Bacillus thuringiensis Cry protein in soil:
           differences between purified toxin and biopesticide formulation
    • Abstract: Background Bacillus thuringiensis produces insecticidal proteins known as Cry and its efficiency and absence of side‐effects make it the most widely used biopesticide. There is little information on the role of soils in the fate of Cry proteins from commercial biopesticide formulations, unlike toxins from genetically modified crops that have been intensively studied in recent years. The persistence of Cry in soil was followed under field and laboratory conditions. Results Sunlight accelerated loss of detectable Cry under laboratory conditions but little effect of shade was observed under field conditions. The half‐life of biopesticide proteins in soil under natural conditions was about one week. Strong temperature effects were observed, but they differed for biopesticide and purified protein, indicating different limiting steps. Conclusion For the biopesticide the observed decline in detectable protein was due to biological factors, possibly including the germination of B. thuringiensis spores and was favoured by higher temperature. In contrast for purified proteins, the decline in detectable protein was slower at low temperature, probably because the conformational changes of the soil‐adsorbed protein, that cause fixation and hence reduced extraction efficiency, are temperature dependent.
      PubDate: 2016-02-23T00:20:27.20191-05:0
      DOI: 10.1002/ps.4262
       
  • Reproduction of the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) B
           biotype in maize fields (Zea mays L.) in Brazil
    • Authors: Eliane D. Quintela; Aluana G. Abreu, Julyana F. dos S. Lima, Gabriel M. Mascarin, Jardel Barbosa dos Santos, Judith K. Brown
      Abstract: Background Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae) was observed to have completed its reproductive cycle from the egg to the adult on maize (Zea mays L.). Field and screen house studies were carried out to investigate the durability of this putative and unprecedented adaptation to a grass host. Results Analysis of the mitochondrial COI gene sequence identified the maize‐associated B. tabaci as the exotic B biotype (major clade North Africa‐Mediterranean‐Middle East). Results showed that whiteflies migrated from soybean crops and successfully established in maize plants. Females exhibited a preference for oviposition primarily on the 1st and 2nd leaves of maize but also were able to colonize developing leaves. A high, natural infestation on maize (193.3 individuals, all developmental stages) was observed within a 7.1‐cm2 designated ‘observation area’. Whiteflies collected from naturally infested maize leaves and allowed to oviposit on maize seedlings grown in a screen house, developed from egg to adulthood in 28.6  ±0.2 days. Conclusion This is the first report of the B biotype completing its development on maize plants. This surprising anomaly indicates that the B biotype is capable of adapting to monocotyledonous host plants, and importantly, broadens the host range to include at least one species in the Poaceae.
      PubDate: 2016-02-22T23:47:45.084418-05:
      DOI: 10.1002/ps.4259
       
  • Toxin stability improvement and toxicity increase against Dipteran and
           Lepidopteran larvae of Bacillus thuringiensis crystal protein Cry2Aa
    • Authors: Jihen Elleuch; Samir Jaoua, Carole Ginibre, Fabrice Chandre, Slim Tounsi, Raida Z. Zghal
      Abstract: Background Bacillus thuringiensis δ‐endotoxins are the most widely used biopesticides for controlling economically important crop pests and disease vectors. Improving its efficacy is of great benefit. Here, an improvement of Cry2Aa δ‐endotoxins toxicity was conducted via a cry gene over‐expression system using P20 from B. thuringiensis israelensis. Results The co‐expression of Cry2Aa with P20 witnessed a 7‐fold increase of its production yield in B. thuringiensis. Generated crystals showed to be significantly more toxic (505.207 µg · g−1, 1.99 mg · l−1 and 1.49 mg · l−1) than the P20‐lacking control (720.78 µg · g−1, 705.69 mg · l−1 and 508.51 mg · l−1) against Ephestia kuehniella, Aedes aegypti and Culex pipiens larvae, respectively. In vitro, processing experiments revealed a P20‐mediated protection of Cry2Aa against degradation under larval gut conditions. Thus, P20 could promote the maintenance of a tightly packaged conformation of Cry2Aa toxins in the larval midgut upon correct activation and binding to its membrane receptor. Conclusion Based on its resistance against excessive proteolysis, Cry2Aa δ‐endotoxins, produced in the presence of P20, could be considered as a successful control agent for E. kuehniella and an effective alternative for mosquitoes control implying its possible exploitation in pest management programs.
      PubDate: 2016-02-22T23:47:43.405893-05:
      DOI: 10.1002/ps.4261
       
  • Hog1p‐activation by marasmic acid through inhibition of the
           histidine kinase Sln1p
    • Abstract: Background The histidine kinase (HK) MoHik1p within the high osmolarity glycerol (HOG) pathway is known to be the target of the fungicide fludioxonil. Treatment of the fungus with fludioxonil causes an uncontrolled hyperactivation of the pathway and cell death. In this study, we used a target based in vivo test system with mutant strains of the rice blast fungus Magnaporthe oryzae to search for new fungicidal compounds having various target locations within the HOG pathway. Mutants with inactivated HOG signalling are resistant to fungicides having the target located in the HOG pathway. Results The HK MoSln1p was identified being involved in the new antifungal mode of action of marasmic acid since single inactivation of the genes MoSLN1, MoSSK1, MoSSK2, MoPBS2 and MoHOG1 resulted in mutant strains resistant against the sesquiterpenoid whereas the wildtype strain and the ΔMohik1‐mutant were susceptible. Western blot analysis of phosphorylated MoHog1p confirmed the hypothesis marasmic acid interfering with the HOG pathway, since a strong phosphorylation of MoHog1p was detectable after sesquiterpenoid treatment in the wildtype strain but not in the ΔMosln1‐mutant. Conclusion This study provides evidence for marasmic acid activating the HOG pathway via the HK MoSln1p and we propose the sesquiterpenoid to have a new mode of action in M. oryzae different to known HOG‐inhibitors, e.g. fludioxonil.
      PubDate: 2016-02-17T01:46:03.400109-05:
      DOI: 10.1002/ps.4257
       
  • RNAi‐mediated Plant Protection against Aphids
    • Abstract: Aphids (Aphididae) are major agricultural pests that cause significant yield losses of crop plants each year by inflicting damage both through the direct effects of feeding and by vectoring harmful plant viruses. Expression of double‐stranded RNA (dsRNA) directed against suitable insect target genes in transgenic plants has been shown to give protection against pests through plant‐mediated RNA interference (RNAi). Thus, as a potential alternative and effective strategy for insect pest management in agricultural practice, plant‐mediated RNAi for aphid control has been received intensive attention in recent years. In this review, the mechanism of RNAi in insects and the so far explored effective RNAi target genes in aphids, their potential applications in development of transgenic plants for aphid control, and the major challenges in these aspects are reviewed and the future perspectives of using plant‐mediated RNAi for aphid control are proposed. This review is intended to be a helpful insight into the generation of aphid‐resistant plants through plant‐mediated RNAi strategy.
      PubDate: 2016-02-17T01:45:55.941575-05:
      DOI: 10.1002/ps.4258
       
  • Time‐dependent sorption of two novel fungicides in soils within a
           regulatory framework
    • Authors: Anna Gulkowska; Ignaz J Buerge, Thomas Poiger, Roy Kasteel
      Abstract: BACKGROUND Convincing experimental evidence suggests increased sorption of pesticides on soil over time, which, so far, has not been considered in the regulatory assessment of leaching to groundwater. Recently, Beulke and van Beinum (2012) proposed a guidance on how to conduct, analyze, and use time‐dependent sorption studies in pesticide registration. The applicability of the recommended experimental setup and fitting procedure was examined for two fungicides, penflufen and fluxapyroxad, in four soils during a 170‐day incubation experiment. RESULTS The apparent distribution coefficient increased by a factor of 2.5 to 4.5 for penflufen and by a factor of 2.5 to 2.8 for fluxapyroxad. The recommended two‐site, one‐rate sorption model adequately described measurements of total mass and liquid phase concentration in the calcium chloride suspension, and the calculated apparent distribution coefficient, passing all prescribed quality criteria for the model fit and parameter reliability. CONCLUSION The guidance is technically mature regarding the experimental setup and parametrization of the sorption model for the two moderately mobile and relatively persistent fungicides under investigation. These parameters can be used for transport modelling in soil, thereby recognizing the existance of the experimentally observed, but in the regulatory leaching assessment of pesticides not yet routinely considered phemomenon of time‐dependent sorption.
      PubDate: 2016-02-15T03:21:18.739861-05:
      DOI: 10.1002/ps.4256
       
  • Strigolactones: how far is their commercial use for agricultural
           purposes?
    • Authors: Maurizio Vurro; Cristina Prandi, Francesca Baroccio
      Abstract: Strigolactones are a class of natural and synthetic compounds that in the latest decade are exciting the scientific community not only for their intriguing biological properties, but also for the potential applications in agriculture. These latter range from the use as hormones to modify and/or manage the plant architecture, to stimulants to induce seed germination of parasitic weeds and thus control their infestation by a reduced seed bank; from "biostimulants" of plant root colonization by arbuscular mycorrhiza fungi, improving plant nutritional capabilities, to other still unknown effects on microbial soil communities. More recently, those compounds are also attracting the interest of agro‐chemical companies. Despite their biological attractiveness, practical applications are still strongly hampered by the low product yields obtainable by plant root exudates, by the costs of their synthesis, by the lacking knowledge of the off‐target effects, and by the not yet specified or properly identified legislation that could regulate the use of those compounds, depending on the agricultural purposes. The aim of this article is to discuss, in the light of the current knowledge, the different "scenarios" that could appear in the near future about bringing strigolactones into the practice.
      PubDate: 2016-02-12T03:36:28.017317-05:
      DOI: 10.1002/ps.4254
       
  • Cross‐resistance to prosulfocarb + S‐metolachlor and
           pyroxasulfone selected by either herbicide in Lolium rigidum
    • Authors: R. Busi; S.B. Powles
      Abstract: Background Weeds can be a greater constraint to crop production than animal pests and pathogens. Pre‐emergence herbicides are crucial in many cropping system to control weeds that have evolved resistance to selective post‐emergence herbicides. In this study we assessed the potential to evolve resistance to the pre‐emergence herbicides prosulfocarb + S‐metolachlor or pyroxasulfone in 50 individual field Lolium rigidum populations collected in a random survey in Western Australia prior to commercialization of those pre‐emergence herbicides. Results This study shows for the first time that in randomly collected L. rigidum field populations the selection with either prosulfocarb + S‐metolachlor or pyroxasulfone can result in concomitant evolution of resistance to both prosulfocarb + S‐metolachlor and pyroxasulfone after three generations. Conclusions In the major weed L. rigidum, traits conferring resistance to new herbicides can be present before herbicide commercialization. Proactive and multi‐disciplinary research (evolutionary ecology, modelling and molecular biology) is required to detect and analyse resistant populations before they can appear in the field. Several studies show that evolved cross‐resistance in weeds is complex and often unpredictable. Thus, long term management of cross‐resistant weeds must be achieved through heterogeneity of selection by effective chemical, cultural and physical weed control strategies that can delay herbicide resistance evolution.
      PubDate: 2016-02-11T02:17:05.355231-05:
      DOI: 10.1002/ps.4253
       
  • Combining electrostatic powder with an insecticide: effect on stored
           product beetles and on the commodity
    • Authors: Christos G Athanassiou; Thomas N Vassilakos, Anna C. Dutton, Nicholas Jessop, David Sherwood, Garry Pease, Andreja Brglez, Clare Storm, Stanislav Trdan
      Abstract: BACKROUND The opportunity to reduce the amount of pirimiphos‐methyl applied to grain by formulating it in an electrostatic powder was investigated. The insecticidal efficacy of pirimiphos‐methyl in EC formulation or formulated using electrostatic powder (EP) as an inert carrier was investigated against; Sitophilus oryzae (L.), Oryzaephilus surinamensis (L.), Rhyzopertha dominica (F.) and Tribolium confusum Jacquelin du Val. Furthermore, the adhesive properties of EP, to rice, corn and wheat, together with the effect on bulk density and bread and pasta making properties were investigated. RESULTS The results showed that pirimiphos‐methyl formulated with EP provided better efficacy against adults when compared to EC formulation for O. surinamensis and T. confusum, but there was no difference for R. dominica. Progeny production was consistently lower in grain treated with the EP formulation than the EC. The adherence tests showed that EP remained on the kernels greater on hard wheat than on maize or rice. In most commodities EP did not alter the bulk density. Finally, the addition of EP did not affect flour and bread making properties, nor the pasta making properties. CONCLUSIONS The results of the present study suggest that an EP could be used to reduce the amount of pirimiphos‐methyl applied to grain for effective pest control with no detrimental effects on grain quality.
      PubDate: 2016-02-11T01:27:40.889661-05:
      DOI: 10.1002/ps.4255
       
  • RNA interference of cytochrome P450 CYP6F subfamily genes affects
           susceptibility to different insecticides in Locusta migratoria
    • Authors: Yanqiong Guo; Haihua Wu, Xueyao Zhang, Enbo Ma, Yaping Guo, Kun Yan Zhu, Jianzhen Zhang
      Abstract: Background Many insect cytochrome P450s (CYPs) play critical roles in detoxification of insecticides. The CYP6 family is unique to the class Insecta and its biochemical function has essentially been associated with the metabolism of xenobiotics. In this study, we sequenced and characterized the full‐length cDNAs of five CYP genes from Locusta migratoria, a highly destructive agricultural pest in the world. Results The five genes were predominantly expressed in brain, guts, fat bodies or Malpighian tubules. CYP6FE1, CYP6FF1, and CYP6FG1 were expressed at higher levels in fourth‐instar nymphs than in other developmental stages. CYPFD2 is specifically expressed in adults, whereas CYP6FG1 showed significantly lower expression in eggs than in other developmental stages. Deltamethrin suppressed CYP6FD1 expression in third‐instar nymphs and up‐regulated the expression level of CYP6FD2, CYP6FF1, and CYP6FG1 at the dose of LD10. Efficient RNA interference‐mediated gene‐silencing was established for four of the five CYP genes. Silencing CYP6FF1 increased the nymphal mortality from 23 to 50% in response to deltamethrin. Silencing CYP6FD2 and CYP6FE1 increased the nymphal mortality from 32 to 72% and 66%, respectively, to carbaryl. Conclusion Three of the four CYP6F subfamily genes in L. migratoria were associated with the detoxification of deltamethrin or carbaryl. The role of CYPs in insecticide detoxification appears to be both gene and insecticide specific.
      PubDate: 2016-02-08T05:18:15.92718-05:0
      DOI: 10.1002/ps.4248
       
  • A novel antagonist discovery of Manduca sexta allatotropin analog as
           insect midgut active ion transport inhibitor
    • Abstract: Background The midgut is an important site for both nutrient absorption and ionic regulation in lepidopteran larvae, major pests in agriculture. The larval lepidopteran midgut has become as an potent insecticide target over the past few decades. Recent studies have shown that an insect neuropeptidde, Manduca sexta allatotropin (Manse‐AT), exhibits inhibition of active ion transport (AIT) across the larval midgut epithelium. The full characteristic of the AIT‐inhibiting ability by Manse‐AT is essential to assay. In this study, the AIT inhibition across M. sexta midgut of Manse‐AT and its analogs at range concentrations was assayed to fully identify their abilities. The structure‐activity relationship of Manse‐AT was also studied by truncated and alanine‐replacement strategies. Results Our results identified three residues, Thr4, Arg6 and Phe8, as the most important components for activity on midgut. Replacement of Glu1, Met2 and Met3 reduced the potency of the analogs. The conservative substitution of Gly7 with alanine had little effect on the potency of the analogs. And we first demonstrated that Manse‐AT (10–13) behaves as a potent Manse‐AT antagonist in vitro on the active ion transport across the epithelium of posterior midguts in M. sexta. Conclusion Structure‐activity studies of Manse‐AT are useful in developing lead compounds for the design and testing of synthetic antagonists to ultimately develop potent and specific pest control strategies. Manse‐AT (10–13) was discovered as the first Manse‐AT antagonist with significant effect and short sequence compared to the other insect neuropeptides. It may be a new potential pest control agent in the future.
      PubDate: 2016-02-08T02:51:57.12867-05:0
      DOI: 10.1002/ps.4251
       
  • Emerging pests and diseases of Southeast Asian cassava: a comprehensive
           evaluation of geographic priorities, management options and research needs
           
    • Authors: Ignazio Graziosi; Nami Minato, Elizabeth Alvarez, Dung Tien Ngo, Hoat Xuan Trinh, Tin Maung Aye, Juan Manuel Pardo, Prapit Wongtiem, Kris A.G. Wyckhuys
      Abstract: Cassava is a major staple, bio‐energy and industrial crop in many parts of the developing world. In Southeast Asia, cassava is grown on >4 million ha by nearly 8 million (small‐scale) farming households, under (climatic, biophysical) conditions that often prove unsuitable for many other crops. While SE Asian cassava has been virtually free of phytosanitary constraints for most of its history, a complex of invasive arthropod pests and plant diseases has recently come to affect local crops. We describe results from a region‐wide monitoring effort in the 2014 dry season, covering 429 fields across five countries. We present geographic distribution and field‐level incidence of the most prominent pest and disease invaders, introduce readily‐available management options and research needs. Monitoring work reveals that several exotic mealybug and (red) mite species have effectively colonized SE Asia's main cassava‐growing areas, occurring in respectively 70% and 54% of fields, at average field‐level incidence of 27±2% and 16±2%. Cassava witches broom (CWB), a systemic phytoplasma disease, was reported from 64% of plots, incidence levels of 32±2%. Although all main pests and diseases are non‐natives, we hypothesize that accelerating intensification of cropping systems, increased climate change and variability, and deficient crop husbandry are aggravating both organism activity and crop susceptibility. Future efforts need to consolidate local capacity to tackle current (and future) pest invaders, boost detection capacity, devise locally‐appropriate integrated pest management (IPM) tactics, and transfer key concepts and technologies to SE Asia's cassava growers. Urgent action is needed to mobilize regional as well as international scientific support, to effectively tackle this phytosanitary emergency and thus safeguard the sustainability and profitability of one of Asia's key agricultural commodities.
      PubDate: 2016-02-08T02:51:55.233954-05:
      DOI: 10.1002/ps.4250
       
  • Movements and habitat preferences of pests help improve population
           control: the case of common brushtail possums in a New Zealand dryland
           ecosystem
    • Authors: Carlos Rouco; Grant L Norbury, Dean P Anderson
      Abstract: Background Introduced brushtail possums are controlled in New Zealand to mitigate their spread of bovine tuberculosis in livestock. Given the low rainfall and extreme variation in seasonal temperatures in dryland areas of the South Island, the habitats of possums in these areas differ in many respects to those in the rest of New Zealand. We investigated the movements and habitat preferences of at two dryland sites to identify where possums aggregate following population control by using GPS collars and cards chewed by possums. At one site, possum numbers were reduced from high levels by 65%, and at the other site, possums had already been reduced to low levels for some time beforehand but were further reduced to maintain them at low levels. This resulted in different possum densities. Results Possum home ranges were about three times smaller at the higher density site, but average ranges expanded by 27% following initial control. Home ranges were already large at the lower density site but did not expand further after maintenance control. No preference for habitat types was apparent at the higher density site, but at the lower density site possums selected rock and shrubby habitats, and avoided open grassy areas. Conclusions Home range sizes and habitat preferences were density‐dependent: the lower the density, the larger the home range; and habitat preferences were highly variable between individuals, but less so for possums at low density. Preference for shrubs and rocks is likely to benefit population control if population control devices are focussed on these habitat types.
      PubDate: 2016-02-08T02:51:34.875803-05:
      DOI: 10.1002/ps.4252
       
  • Binding of imidacloprid, thiamethoxam and N‐desmethylthiamethoxam to
           nicotinic receptors of Myzus persicae: pharmocological profiling using
           neonicotinoids, natural agonists and antagonists
    • Authors: Hartmut Kayser; Katrin Lehmann, Marilyne Gomes, Wolfgang Schleicher, Karin Dotzauer, Margarethe Moron, Peter Maienfisch
      Abstract: Background The increasing structural diversity of neonicotinoid class of insecticides presently used in crop protection calls for a more detailed analysis of their mode of action at their cellular targets, the nicotinic acetylcholine receptors. Results Comparative radioligand binding studies using membranes of Myzus persicae (Sulzer) and representatives of the chloropyridyl subclass (imidacloprid), the chlorothiazolyl subclass (thiamethoxam), the tetrahydrofuranyl subclass (dinotefuran), as wells as the novel sulfoximine type (sulfoxaflor), which is not a neonicotinoid, reveal significant differences in: the number of binding sites the displacing potencies the mode of binding interference Furthermore, the mode of interaction of [3H]thiamethoxam and the nicotinic antagonists methyllycaconitine and dihydro‐β‐erythroidine is unique with Hill values >1, clearly different to the values around unity of [3H]imidacloprid and [3H]N‐desmethylthiamethoxam, respectively. The interaction of [3H]N‐desmethylthiamethoxam with the agonist (−)nicotine is characterised also by a Hill value >1. Conclusions There is no single conserved site or mode of binding of neonicotinoids and related nicotinic ligands to their target receptor, but a variety of binding pockets depending on the combination of receptor subunits, the receptor subtype, its functional state, as well as the structural flexibility of both the binding pockets and the ligands.
      PubDate: 2016-02-04T01:46:23.906971-05:
      DOI: 10.1002/ps.4249
       
  • Development of a CO2 releasing co‐formulation based on starch,
           Saccharomyces cerevisiae and Beauveria bassiana attractive towards western
           corn rootworm larvae
    • Abstract: Background CO2 is known as an attractant for many soil‐dwelling pests. To implement an attract‐and‐kill strategy for soil pest control, CO2 emitting formulations need to be developed. This work aimed at the development of a slow release bead system in order to bridge the gap between application and hatching of western corn rootworm larvae. Results We compared different Ca‐alginate beads containing Saccharomyces cerevisiae for their potential to release CO2 during several weeks. Addition of starch improved CO2 release resulting in significantly higher CO2 concentrations in soil for at least four weeks. The missing amylase activity was compensated either by microorganisms present in soil or by co‐encapsulation of Beauveria bassiana. Formulations containing S. cerevisiae, starch and B. bassiana were attractive for western corn rootworm larvae within the first 4 h following exposure; however, when considering the whole testing period the maize root systems remained more attractive for the larvae. Conclusion Co‐encapsulation of S. cerevisiae, starch and B. bassiana is a promising approach for the development of attractive formulations for soil applications. For biological control strategies, the attractiveness needs to be increased by phagostimuli to extend contact between larvae and the entomopathogenic fungus growing out of these formulations.
      PubDate: 2016-02-02T02:09:33.523193-05:
      DOI: 10.1002/ps.4245
       
  • Allelobiosis in the interference of allelopathic wheat with weeds
    • Abstract: Background Plants may chemically affect the performance of neighboring plants through allelopathy, allelobiosis or both. Despite increasing knowledge of allelobiosis defined as the signaling interactions mediated by nontoxic chemicals involved in plant‐plant interactions, the phenomenon has received relatively little attention in the scientific literature. This study examined the role of allelobiosis in the interference of allelopathic wheat with weeds. Results Allelopathic wheat inhibited the growth of five weed species tested, and the allelochemical (2,4‐dihydroxy‐7‐methoxy‐1,4‐benzoxazin‐3‐one, DIMBOA) production of wheat was elicited in the presence of these weeds, even with root segregation. The inhibition and allelochemical levels varied greatly with the mixed‐species density. The increased inhibition and allelochemical levels occurred at low and medium densities but declined at high densities. All the root exudates and their components of jasmonic acid and salicylic acid from five weeds stimulated allelochemical production. Furthermore, jasmonic acid and salicylic acid were found in plants, root exudates and rhizosphere soils regardless of weed species, indicating their participating in the signaling interactions defined as allelobiosis. Conclusion Through root‐secreted chemical signals, allelopathic wheat can detect competing weeds and respond by increased allelochemical levels to inhibit them, providing an advantage for its own growth. Allelopathy and allelobiosis are two probably inseparable processes that occur together in wheat‐weed chemical interactions.
      PubDate: 2016-02-02T02:09:32.471946-05:
      DOI: 10.1002/ps.4246
       
  • Modelling the current and potential future distributions of the sunn pest
           Eurygaster integriceps (Hemiptera: Scutelleridae) using CLIMEX
    • Authors: Rasha Aljaryian; Lalit Kumar, Subhashni Taylor
      Abstract: Background The sunn pest, Eurygaster integriceps (Hemiptera: Scutelleridae) is an economically significant pest throughout Western Asia and Eastern Europe. This study was conducted to examine the possible risk posed by the influence of climate change on its spread. CLIMEX software was used to model its current global distribution. Future invasion potential was investigated using two global climate models (GCMs), CSIRO‐Mk3.0 (CS) and MIROC‐H (MR), under A1B and A2 emission scenarios for 2030, 2070 and 2100. Results Dry to temperate climatic areas favour sunn pests. The potential global range for E. integriceps is expected to extend further pole‐wards between latitudes 60°N and 70°N. Northern Europe and Canada will be at risk of sunn pest invasion as cold stress boundaries recede under the emission scenarios of these models. However, current highly suitable areas, such as South Africa and central Australia, will contract where precipitation is projected to decrease substantially with increased heat stress. Conclusion Estimating the sunn pest's potential geographic distribution and detecting its climatic limits can provide useful information for management strategies and allow biosecurity authorities to plan ahead and reduce the expected harmful economic consequences by identifying the new areas for pest invasion.
      PubDate: 2016-02-02T02:08:02.582259-05:
      DOI: 10.1002/ps.4247
       
  • INSECTICIDAL POTENCY OF RNAi BASED CATALASE KNOCKDOWN IN RHYNCHOPHORUS
           FERRUGINEUS (OLIVIER) (COLEOPTERA: CURCULIONIDAE)
    • Abstract: Background Palm trees around the world are prone to notorious Rhynchophorus ferrugineus, which causes heavy losses of palm plantations. In the Middle Eastern countries, this pest is a major threat to the date palm orchards. Conventional pest control measures with the major share of synthetic insecticides have resulted in insect resistance and environmental issues. Therefore, in order to explore better alternative, RNAi approach was employed to knockdown catalase gene in 5th & 10th larval instars under different dsRNA application methods and their insecticidal potency was studied. Results dsRNA of 444bp was prepared to knockdown catalase in Rhynchophorus ferrugineus. Out of the three dsRNA application methods, dsRNA injection into larvae was the most effective followed by dsRNA application by artificial feeding. Both the methods resulted in the significant catalase knockdown in various tissues especially midgut. As a result, the highest growth inhibition of 123.49% & 103.47% and larval mortality of 80% & 40% was observed in 5th instar larvae whereas the larval growth inhibition remained as 86.83% & 69.08 % with larval mortality of 30% & 10% in 10th instar larvae after dsRNA injection & artificial diet treatment. Topical application method was least efficient with the lowest larval growth inhibition 57.23% & 45.61% and 0% mortality in 5th & 10th instar larvae. Generally, better results were noted at high dsRNA dose 5 µl. Conclusion Catalase enzyme is found in most of the insect body tissues and thus its dsRNA can cause broad scale gene knockdown inside insect body, depending upon application method. Significant larval mortality and growth inhibition after catalase knockdown in Rhynchophorus ferrugineus confirms its insecticidal potency and exhibits the sparkling future of RNAi based bio‐insecticides for pest control.
      PubDate: 2016-01-29T02:34:10.226571-05:
      DOI: 10.1002/ps.4242
       
  • Emergence of SDHI resistance of Pyrenophora teres in Europe
    • Authors: Alexandra Rehfus; Simone Miessner, Janosch Achenbach, Dieter Strobel, Rosie Bryson, Gerd Stammler
      Abstract: Background Net blotch caused by Pyrenophora teres is an important disease of barley worldwide. In addition to strobilurins (QoIs) and azoles (DMIs), succinate dehydrogenase inhibitors (SDHIs) are very effective fungicides for net blotch control. Recently, SDHI resistant isolates have been found in the field. Intensive sensitivity monitoring programmes across Europe were carried out to investigate the situation of SDHI resistance in P. teres. Results The first isolates with a lower sensitivity to SDHIs registered in barley were found in Germany in 2012 and carried the B‐H277Y substitution in succinate dehydrogenase enzyme. In 2013 and 2014 a significant increase of isolates with lower SDHI sensitivity was detected mainly in France and Germany and the range of target site mutations increased. Most of the resistant isolates carried the C‐G79R substitution which exhibits a strong impact on all SDHIs in microtiter tests. All SDHIs tested were shown to be cross‐resistant. Other substitutions are gaining in importance, e.g. C‐N75S in France and D‐D145G in Germany. So far, no double mutants in SDH genes have been detected. Glasshouse tests showed that SDHI resistant isolates were still controlled by the SDHI fluxapyroxad when applied preventative. To date, most isolates with C‐G79R substitution did not simultaneously carry the F129L change in cytochrome b, which causes resistance towards QoI fungicides at low to moderate levels. Conclusion Several target site mutations in the genes of subunits SDH‐B, SDH‐C and SDH‐D with different impact on SDHI fungicides were detected. The pattern of mutations varied from year to year and between different regions. Strict resistance management strategies are recommended to maintain SDHIs as effective tools for net blotch control, especially in areas with low frequencies of resistant isolates.
      PubDate: 2016-01-29T02:33:32.71479-05:0
      DOI: 10.1002/ps.4244
       
  • Development of a rapid and high‐throughput molecular method for
           detecting the F200Y mutant genotype in benzimidazole‐resistant
           isolates of Fusarium asiaticum
    • Authors: Ya Bing Duan; Ying Yang, Tao Li, Donglei Zhao, Jun Hong Cao, Yi Yuan Shi, Jian Xin Wang, Ming Guo Zhou
      Abstract: Background The point mutation at codon 200 (TTC→TAC, F200Y) of the β2‐tubulin gene confers resistance to benzimidazole fungicide in Fusarium asiaticum. These isolates with this mutation have been detected mainly by determining the minimum inhibitory concentration (MIC) of fungicides, which is always time‐consuming, tedious and inefficient. Results A visual, rapid and efficient method with high specificity was developed based on loop‐mediated isothermal amplification (LAMP). Six sets of LAMP primers were designed and only one set was optimized to specially distinguish the F200Y mutant genotype. With the optimal LAMP primers, concentrations of LAMP components were optimized. The optimal reaction conditions were 57‐64°C for 75 min. The feasibility of the LAMP assay for detection of the F200Y mutant genotype of F. asiaticum was demonstrated by assaying the diseased wheat spikelets that were artificially inoculated in the field. Conclusion The new LAMP assay had a good specificity, sensitivity, stability and repeatability. It will be useful for assessing the risk that F. asiaticum populations with carbendazim resistance will develop in the field and will also provide important reference data for integrated control of Fusarium head blight caused by F. asiaticum.
      PubDate: 2016-01-29T02:33:21.006981-05:
      DOI: 10.1002/ps.4243
       
  • Mechanism of leaf‐cutting ant colony suppression by fipronil used in
           attractive toxic baits
    • Authors: Lailla C Gandra; Karina D Amaral, Joel C Couceiro, Terezinha Maria C Della Lucia, Raul Narciso C Guedes
      Abstract: Background Attractive toxic baits are the prevailing method for managing leaf‐cutting ants in the eucalypt forests planted for the production of pulp, paper, timber, and charcoal. For successful use in these baits, the insecticidal compounds need to circumvent the typical defenses of the eusocial leaf‐cutting ants. The challenge is to have an insecticide in the bait that will not directly harm and/or compromise foraging workers, but which will eventually suppress the colony. These underlying mechanisms are poorly known and here the potential mechanism of fipronil activity in toxic baits for leaf‐cutting ants was assessed using colonies of the representative Neotropical Acromyrmex subterraneus subterraneus (Forel, 1893). Results Although forager activity was not directly impaired by fipronil, the insecticide affected forager nestmate interactions (auto and allogrooming) and waste removal and, more importantly, greatly affected the minor workers, impairing their activities of fungus garden cultivation and progeny handling. The fast decay of the fungus garden compromised the sustainability of the colonies ultimately leading to their demise within eight days. Conclusion The behavioral effects of sublethal insecticide exposure towards minor workers are the main determinants of insecticide activity as ant baits and should be targeted in developing such compounds.
      PubDate: 2016-01-27T23:09:03.47076-05:0
      DOI: 10.1002/ps.4239
       
  • Effects of selected herbicides and fungicides on growth, sporulation and
           conidial germination of entomopathogenic fungus Beauveria bassiana
    • Authors: Franci A. Celar; Katarina Kos
      Abstract: Background The in vitro fungicidal effects of six commonly used fungicides viz. fluazinam, propineb, copper II hydroxide, metiram, chlorothalonil and mancozeb, and herbicides viz. isoxaflutole, fluazifop‐P‐butyl, flurochloridone, foramsulfuron, pendimethalin and prosulfocarb on mycelial growth, sporulation and conidial germination of entomopathogenic fungus Beauveria bassiana (ATCC 74040) was investigated. Mycelial growth rates and sporulation at 15 and 25 °C were evaluated on PDA plates containing 100, 75, 50, 25, 12.5, 6.25 and 0% of recommended application rate of each pesticide. The tested pesticides were classified in 4 scoring categories based on reduction of mycelial and sporulation. Results All pesticides, herbicides and fungicides, tested had fungistatic effect of varying intensities, dependent on their rate in medium, on B. bassiana. Most inhibitory herbicides were flurochloridone and prosulfocarb; and fluazinam and copper II hydroxide among fungicides, meanwhile the least inhibitory were isoxaflutole and chlorothalonil. Sporulation and conidial germination of B. bassiana were significantly inhibited by all tested pesticides compared to control treatment. Flurochloridone, foramsulfuron, prosulfocarb and copper II hydroxide entirely inhibited sporulation at 100% rate (99‐100% inhibition), and the lowest inhibition was shown at fluazifop‐P‐butyl (22%) and metiram (33%). At 100% dosage all herbicides in test showed high inhibitory effect on conidial germination. Conidial germination inhibition ranged from 82% at isoxaflutole to 100% at fluorochloridone, pendimethalin and prosulfocarb. At 200% dosage, inhibition rates even increased (96‐100%). Conclusions All twelve pesticides tested had fungistatic effect to B. bassiana at varying intensities dependind on the pesticide and its concentration. B. bassiana is highly affected by some herbicides and fungicides even at very low rates. Flurochloridone, foramsulfuron, prosulfocarb and copper II hydroxide have stopped sporulation. Of all tested pesticides, isoxaflutole, fluazifop‐P‐butyl and chlorothalonil showed the least adverse effects and therefore probably could be compatible with B. bassiana in the field.
      PubDate: 2016-01-27T23:08:59.749105-05:
      DOI: 10.1002/ps.4240
       
  • Mineralization and Degradation of 2,4‐D Dimethylamine Salt in a
           Biobed Matrix and in Topsoil
    • Authors: J. Diane Knight; Allan J. Cessna, Dean Ngombe, Tom M. Wolfe
      Abstract: Background Biobeds are used for on‐farm bioremediation of pesticides in sprayer rinsate and from spills during sprayer filling. Using locally‐sourced materials from Saskatchewan Canada, a biobed matrix was evaluated for its effectiveness for mineralizing and degrading 2,4‐D DMA compared to the topsoil used in the biobed matrix. Results Applying 2,4‐D DMA to the biobed‐matrix caused a 2‐ to 3‐d lag in CO2 production not observed when the herbicide was applied to topsoil. Despite the initial lag, less residual 2,4‐D was measured in the biobed (0%) matrix than in the topsoil (57%) after a 28‐d incubation. When the herbicide was applied five times to the biobed matrix, net CO2 increased immediately after each 2,4‐D DMA application. Mineralization of 2,4‐D DMA was 61.9% and residual 2,4‐D in the biobed matrix 0.3% after 60 d, compared to corresponding values of 32.9 and 70.9% in topsoil. Conclusion Biobed‐matrix enhanced mineralization and degradation of 2,4‐D DMA, indicating the potential for successful implementation of biobeds under Canadian conditions. The biobed matrix was more effective for mineralizing and degrading the herbicide compared to the topsoil used in the biobed matrix. By correcting for biobed matrix and formulation blank, CO2 evolution was a reliable indicator of 2,4‐D DMA mineralization.
      PubDate: 2016-01-27T23:01:58.102756-05:
      DOI: 10.1002/ps.4238
       
  • Volatiles released by Chinese liquorice roots mediate host location
           behavior by neonate Porphyrophora sophorae (Hemiptera: Margarodidae)
    • Abstract: Background The cochineal scale, Porphyrophora sophorae (Hemiptera: Coccoidea, Margarodidae), is one of the most serious arthropod pests of Chinese liquorice, Glycyrrhiza uralensis (Fabaceae), an important medicinal herb. The adult females tend to deposit the ovisacs in soil relatively far away from liquorice plants. After hatching, neonates move out of the soil and may use chemical cues to search for new hosts. Results We collected and analyzed the volatiles from soils with and without liquorice roots and chromatographic profiles revealed hexanal, β‐pinene, and hexanol as potential host‐finding cues for P. sphorae. The attractiveness of these compounds to neonates was studied in the laboratory using four‐arm olfactometer bioassays. The larvae showed a clear preference for β‐pinene over hexanal and hexanol, as well as all possible combinations of the three compounds. In addition, a field experiment confirmed that β‐pinene was significantly more attractive than hexanal and hexanol. Conclusion Newly‐eclosed larvae of P. sphorae exploit root volatiles as chemical cues to locate their host plant. β‐pinene proved to be the major chemical cue used by P. sphorae neonates searching for roots of their host plant.
      PubDate: 2016-01-27T23:01:53.458854-05:
      DOI: 10.1002/ps.4237
       
  • The potential of coumatetralyl enhanced by cholecalciferol in the control
           of anticoagulant resistant Norway rats (Rattus norvegicus)
    • Abstract: Background We evaluated the potential of cholecalciferol as an enhancer of the first generation anticoagulant coumatetralyl in the Westphalia anticoagulant‐resistant strain of the Norway rat (Rattus norvegicus BERKENHOUT), characterized by the Tyr139Cys polymorphism on the VKOR enzyme. Because today only the most potent, but also most persistent anticoagulant rodenticides of the second generation remain available to control this strain, new rodenticide solutions are required. Results Feeding trials in the laboratory confirmed a significant level of efficacy, which was corroborated by field trials in the Münsterland resistance area. After frequency and level of resistance were assessed by BCR‐tests, field trials were conducted with bait containing coumatetralyl at 375 mg/kg and cholecalciferol at 50 mg/kg or 100 mg/kg. Control success was 94 per‐cent when a large rat infestation comprising 42 per‐cent resistant animals was treated. Another field trial applying the combination to a rat population, which had survived a preceding treatment with bromadiolone, resulted in a 99.5 per‐cent control success according to the first census day, but with some increase in rat activity during subsequent census days. Conclusion The combination of coumatetralyl and cholecalciferol is a promising alternative approach in the management of Norway rats resistant to the most potent second generation anticoagulants, particularly in respect to environmental risks, such as secondary poisoning.
      PubDate: 2016-01-22T02:22:33.041408-05:
      DOI: 10.1002/ps.4235
       
  • Establishment of the PEG‐mediated protoplast transformation for
           Lecanicillium lecanii and development of virulence‐enhanced strains
           against Aphis gossypii
    • Abstract: Background Lecanicillium lecanii has been developed as biopesticides and used in biological control of several agricultural insects. To improve fungal virulence, an optimized PEG‐mediated protoplast transformation system was established for L. lecanii. Pr1A‐like cuticle degrading protease gene (Cdep1) from Beauveria bassiana was transferred into L. lecanii and its resulting activity against Aphis gossypii was assessed. Results The optimized protoplast generation yielded 2.5×108 protoplasts/g wet mycelium of fungi, and gave nearly 98% viability and 80% regeneration on plates. Protease activities were increased about 5‐fold in transformants expressing CDEP1. The median lethal concentration (LC50) for transformants expressing CDEP1 was 2‐fold lower than that for the wild type (WT). The median survival time (LT50) for transformants expressing CDEP1 was also 14.2% shorter than that for WT though no significant difference. There were no significant differences in conidia germination as colony growth and conidia yield on plates between transformants expressing CDEP1 and WT. The transformants expressing CDEP1 grew significantly quicker than WT in insects. The transformants expressing CDEP1 were lower in conidia yields on insect cadavers, but insignificant different from WT. Conclusion The PEG‐mediated protoplast transformation system was effective for L. lecanii, and the expression of CDEP1 significantly enhanced fungal virulence against cotton aphids.
      PubDate: 2016-01-22T02:22:11.765291-05:
      DOI: 10.1002/ps.4236
       
  • Leaf morphology‐assisted selection for resistance to
           two‐spotted spider mite Tetranychus urticae Koch (Acari:
           Tetranychidae) in carnations (Dianthus caryophyllus L)
    • Authors: Kousuke Seki
      Abstract: Background The development of two‐spotted spider mite‐resistant cultivar has provided both ecological and economic benefits to cut‐flower production. This study aimed to clarify the mechanism of resistance to mite using an inbred population of carnation. Results In the resistant and susceptible plants selected from an inbred population, a difference was recognized in the thickness of the abaxial palisade tissue by microscopic examination of the damaged leaf. Therefore, it was assumed that mites displayed feeding preferences within the internal leaf structure of the carnation leaf. The suitability of the host plant for mites was investigated using several cultivars selected using an index of the thickness from the abaxial leaf surface to the spongy tissue. The results suggested that the cultivar associated with a thicker abaxial tissue lowered the intrinsic rate of natural increase of the mites. The cultivars with a thicker abaxial tissue of over 120 µm showed slight damage in the field test. Conclusion The ability of mites to feed on the spongy tissue during an early life‐stage from hatching to adult emergence was critical. It was possible to select the cultivar which is resistant to mites under a real cultivation environment by observing the internal structure of the leaf.
      PubDate: 2016-01-22T02:21:28.809474-05:
      DOI: 10.1002/ps.4231
       
  • The use of substituted alkynyl phenoxy derivatives of piperonyl butoxide
           to control insecticide‐resistant pests
    • Authors: Despina Philippou; Valerio Borzatta, Elisa Capparella, Leni Moroni, Linda Field, Graham Moores
      Abstract: Background Derivatives of piperonyl butoxide with alkynyl side‐chains were tested in vitro and in vivo against pyrethroid‐resistant Meligethes aeneus and imidacloprid‐resistant Myzus persicae. Results Synergists with the alkynyl side‐chain were more effective inhibitors of P450 activity in vitro than piperonyl butoxide, and demonstrated high levels of synergism in vivo, with up to 290‐fold synergism of imidacloprid against imidacloprid‐resistant Myzus persicae. Conclusions These “second generation” synergists could overcome metabolic resistance in many pest species and possibly enable reduced rates of insecticide application in some cases.
      PubDate: 2016-01-21T11:53:38.642226-05:
      DOI: 10.1002/ps.4234
       
  • Foliar applications of micro‐doses of sucrose to reduce codling moth
           Cydia pomonella L. (Lepidoptera, Tortricidae) damages on apple tree
    • Abstract: BACKGROUND The effects of foliar applications of micro‐doses of sucrose to reduce the damages of the codling moth have been reported from nine trials carried in France and Algeria from 2009 to 2014. The activity of sucrose alone was assessed by comparison with an untreated control and some treatments with the Cydia pomonella granulovirusis or a chemical insecticide. The addition of sucrose to these different treatments was also investigated. RESULTS The application of sucrose at 0.01% reduced the means of infested fruits with a value of Abbott efficacy of 41.0 ± 10.0%. It's about a induction of resistance by antixenosis to the insect egg‐laying. Indeed, it seems that acceptance of the egg‐laying on leaves treated with sucrose was reduced. The addition of sucrose to thiacloprid improved its efficacy (59.5% ± 12.8) with 18.4%. However, the sucrose had no added value associated in the Cydia pomonella granulovirusis treatments. CONCLUSION Foliar applications of micro‐doses of sucrose every twenty days in commercial orchards can protect partially against the codling moth. Its addition to thiacloprid increases the efficacy in integrated control strategies contrary to Cydia pomonella granulovirusis treatments. This work opens a route for the development of new biocontrol strategies.
      PubDate: 2016-01-12T02:40:14.713131-05:
      DOI: 10.1002/ps.4228
       
  • Choosing the best cropping systems to target pleiotropic effects when
           managing single‐gene herbicide resistance in grass weeds. A
           blackgrass simulation study
    • Abstract: Background Managing herbicide‐resistant weeds is becoming increasingly difficult. Here we adapted the weed dynamics model AlomySys to account for experimentally‐measured fitness costs linked to mutants of target‐site resistance to acetyl‐coenzyme A carboxylase (ACCase)‐inhibiting herbicides in Alopecurus myosuroides. We ran simulations to test how effectively cultural practices manage resistance. Results Simulations of an oilseed rape/winter wheat/winter barley rotation showed that, when replacing one of the seven applied herbicides by an ACCase‐inhibiting one, resistant mutants exceeded 1 plant/m2 with a probability of 40%, after an average of 18 years. This threshold was always exceeded when three or four ACCase‐inhibiting herbicides were used, after an average of 8 and 6 years, respectively. With reduced herbicide rates or suboptimal spraying conditions, resistance occurred 1–3 years earlier in 50% of simulations. Adding spring pea to the rotation or yearly moldboard ploughing delayed resistance indefinitely in 90% and in 60% of simulations, respectively. Ploughing also modified the genetic composition of the resistant population by selecting a previously rare mutant that presented improved pre‐emergent growth. The prevalence of the mutations was influenced more by their associated fitness cost or benefit than by the number of ACCase‐inhibiting herbicides to which they conferred resistance. Conclusion Simulations allowed us to rank weed management practices and suggest that pleiotropic effects are extremely important for understanding the frequency of herbicide resistance in the population.
      PubDate: 2016-01-11T02:35:50.133054-05:
      DOI: 10.1002/ps.4230
       
  • Neonicotinoid Concentrations in UK Honey from 2013
    • Authors: Ainsley Jones; Gordon Turnbull
      Abstract: Background Concentrations of the neonicotinoid insecticides clothianidin, thiamethoxam and imidacloprid were determined in honey collected in Spring 2013 from a variety of locations in England. The honey was produced before the moratorium in the EU on the use of neonicotinoids in pollinator‐attractive crops became effective. Results Neither imidacloprid, not its metabolites were detected in any honey samples. Concentrations of clothianidin ranged from
      PubDate: 2016-01-11T02:35:20.434718-05:
      DOI: 10.1002/ps.4227
       
  • Molecular Modeling of Sulfoxaflor and Neonicotinoid Binding in Insect
           Nicotinic Acetylcholine Receptors: Impact of the Myzus β1 R81T
           Mutation
    • Authors: Nick X. Wang; Gerald B. Watson, Michael R Loso, Thomas C. Sparks
      Abstract: Background Sulfoxaflor (Isoclast™ active), a new sulfoximine class insecticide, targets sap‐feeding insect pests including those resistant to neonicotinoids. Sulfoxaflor acts on the insect nicotinic acetylcholine receptor (nAChR) in a distinct manner relative to neonicotinoids. Unlike any of the neonicotinoids, sulfoxaflor has four stereoisomers. A homology model of Myzus persicae (green peach aphid) based on the ACh binding protein from Aplysia californica, overlaid with M. persicae nAChR sequence (α2 and β1 subunits) was used to investigate the interactions of the sulfoxaflor stereoisomers with WT and R81T versions of the nAChR. Results Whole molecule van der Waals interactions are highly correlated with the binding affinity for the neonicotinoids and correctly predict the rank‐order of binding affinity for neonicotinoids and sulfoxaflor. The R81T mutation in M. persicae nAChR is predicted to have much less effect on binding of sulfoxaflor's stereoisomers than that of the neonicotinoids. Conclusions All four stereoisomers predictably contribute to the activity of sulfoxaflor. The WT and R81T nAChR homology models suggest that changes in a whole molecule electrostatic energy component can potentially explain the effects of this target‐site mutation on the pattern of reduced efficacy for the modeled neonicotinoids, and provides a basis for the reduced effect of this mutation on sulfoxaflor.
      PubDate: 2016-01-06T00:42:48.218181-05:
      DOI: 10.1002/ps.4220
       
  • Sensor‐based variable‐rate fungicide application in winter
           wheat
    • Abstract: Background Currently, no technology to automatically detect diseases while moving agricultural equipment through fields is available on the market. An alternative approach for target‐oriented fungicide spraying was tested to adapt the local dose rates of spray liquid in winter wheat to local differences in the plant surface and biomass by using a camera sensor. Results A linear correlation was found between the sensor values and two plant parameters, namely, the leaf area index and biomass. The spray volume was linearly adapted to the local sensor value in a field trial. The camera sensor was used to adequately operate the dosing system (gauge) at the field boom sprayer. A total of 8% of the spray liquid was saved compared to common uniform spraying. Conclusions Because no differences exist in the yield and disease incidence between the sensor‐based and uniformly sprayed plot, this new technology, which uses plants as targets for fungicide dosages, could be an alternative to the present common dosage practices on a hectare basis.
      PubDate: 2016-01-06T00:41:26.56001-05:0
      DOI: 10.1002/ps.4225
       
  • Issue Information ‐ Aims and Scope
    • Pages: 1067 - 1067
      PubDate: 2016-04-27T03:35:33.753797-05:
      DOI: 10.1002/ps.4122
       
  • Issue Information ‐ Info Page
    • Pages: 1068 - 1068
      PubDate: 2016-04-27T03:35:33.654408-05:
      DOI: 10.1002/ps.4123
       
  • Issue Information ‐ ToC
    • Pages: 1069 - 1070
      PubDate: 2016-04-27T03:35:29.435819-05:
      DOI: 10.1002/ps.4124
       
  • Uptake and translocation of imidacloprid, clothianidin and flupyradifurone
           in seed‐treated soybeans
    • Pages: 1099 - 1109
      Abstract: BACKGROUND Seed treatment insecticides have become a popular management option for early‐season insect control. This study investigated the total uptake and translocation of seed‐applied [14C]imidacloprid, [14C]clothianidin and [14C]flupyradifurone into different plant parts in three soybean vegetative stages (VC, V1 and V2). The effects of soil moisture stress on insecticide uptake and translocation were also assessed among treatments. We hypothesized that (1) uptake and translocation would be different among the insecticides owing to differences in water solubility, and (2) moisture stress would increase insecticide uptake and translocation. RESULTS Uptake and translocation did not follow a clear trend in the three vegetative stages. Initially, flupyradifurone uptake was greater than clothianidin uptake in VC soybeans. In V1 soybeans, differences in uptake among the three insecticides were not apparent and unaffected by soil moisture stress. Clothianidin was negatively affected by soil moisture stress in V2 soybeans, while imidacloprid and flupyradifurone were unaffected. Specifically, soil moisture stress had a positive effect on the distribution of flupyradifurone in leaves. This was not observed with the neonicotinoids. CONCLUSIONS This study enhances our understanding of the uptake and distribution of insecticides used as seed treatments in soybean. The uptake and translocation of these insecticides differed in response to soil moisture stress. © 2015 Society of Chemical Industry
      PubDate: 2015-10-14T06:46:01.424714-05:
      DOI: 10.1002/ps.4152
       
  • Intraguild predation of Geocoris punctipes on Eretmocerus eremicus and its
           influence on the control of the whitefly Trialeurodes vaporariorum
    • Pages: 1110 - 1116
      Abstract: BACKGROUND Geocoris punctipes (Hemiptera: Lygaeidae) and Eretmocerus eremicus (Hymenoptera: Aphelinidae) are whitefly natural enemies. Previously, under laboratory conditions, we showed that G. punctipes engages in intraguild predation (IGP), the attack of one natural enemy by another, on E. eremicus. However, it is unknown whether this IGP interaction takes place under more complex scenarios, such as semi‐field conditions. Even more importantly, the effect of this interaction on the density of the prey population requires investigation. Therefore, the present study aimed to establish whether this IGP takes place under semi‐field conditions and to determine whether the predation rate of G. punctipes on the whitefly decreases when IGP takes place. RESULTS Molecular analysis showed that, under semi‐field conditions, G. punctipes performed IGP on E. eremicus. However, although IGP did take place, the predation rate by G. punctipes on the whitefly was nevertheless higher when both natural enemies were present together than when the predator was present alone. CONCLUSION While IGP of G. punctipes on E. eremicus does occur under semi‐field conditions, it does not adversely affect whitefly control. The concomitant use of these two natural enemies seems a valid option for inundative biological control programmes of T. vaporariorum in tomato. © 2015 Society of Chemical Industry
      PubDate: 2015-10-27T08:17:32.52839-05:0
      DOI: 10.1002/ps.4163
       
  • Photochemical degradation of imazosulfuron under simulated California rice
           field conditions
    • Authors: Caitlin C Rering; Monica A Gonzalez, Megan R Keener, David B Ball, Ronald S Tjeerdema
      Pages: 1117 - 1123
      Abstract: BACKGROUND The photodegradation of imazosulfuron (IMZ), a potent broad‐spectrum herbicide, was investigated under simulated rice field conditions. Previous reports have indicated that it is photolabile, but have failed to report radiation intensity or determine a quantum yield, precluding extrapolation to environmental rates. Therefore, the objective of this investigation was to determine the photolytic rate of IMZ under simulated rice field conditions and how it is influenced by environmental factors such as turbidity, salinity and temperature. RESULTS IMZ was efficiently photolyzed in all solutions and fitted pseudo‐first‐order kinetics. Degradation was faster in HPLC‐grade water than in field water. Field‐relevant variances in temperature, turbidity and salinity did not significantly influence degradation. The experimentally derived quantum yield for direct photolysis (2.94 × 103) was used to predict the half‐life of IMZ in a California rice field (3.6 days). CONCLUSIONS Aqueous photolysis is predicted to be an important process in the overall degradation of IMZ in the environment, regardless of variances in salinity, organic matter and temperature. Based on the predicted half‐life of IMZ in a California rice field (3.6 days), state‐mandated holding periods for field water post‐IMZ application (30 days) are expected to allow for sufficient clearance of the herbicide (>98%), preventing significant contamination of the environment upon release of tailwater. © 2015 Society of Chemical Industry
      PubDate: 2015-08-17T06:08:29.029925-05:
      DOI: 10.1002/ps.4086
       
  • Corn stover harvest increases herbicide movement to subsurface
           drains – Root Zone Water Quality Model simulations
    • Authors: Martin J Shipitalo; Robert W Malone, Liwang Ma, Bernard T Nolan, Rameshwar S Kanwar, Dale L Shaner, Carl H Pederson
      Pages: 1124 - 1132
      Abstract: BACKGROUND Crop residue removal for bioenergy production can alter soil hydrologic properties and the movement of agrochemicals to subsurface drains. The Root Zone Water Quality Model (RZWQM), previously calibrated using measured flow and atrazine concentrations in drainage from a 0.4 ha chisel‐tilled plot, was used to investigate effects of 50 and 100% corn (Zea mays L.) stover harvest and the accompanying reductions in soil crust hydraulic conductivity and total macroporosity on transport of atrazine, metolachlor and metolachlor oxanilic acid (OXA). RESULTS The model accurately simulated field‐measured metolachlor transport in drainage. A 3 year simulation indicated that 50% residue removal reduced subsurface drainage by 31% and increased atrazine and metolachlor transport in drainage 4–5‐fold when surface crust conductivity and macroporosity were reduced by 25%. Based on its measured sorption coefficient, approximately twofold reductions in OXA losses were simulated with residue removal. CONCLUSION The RZWQM indicated that, if corn stover harvest reduces crust conductivity and soil macroporosity, losses of atrazine and metolachlor in subsurface drainage will increase owing to reduced sorption related to more water moving through fewer macropores. Losses of the metolachlor degradation product OXA will decrease as a result of the more rapid movement of the parent compound into the soil. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.
      PubDate: 2015-08-14T07:19:04.007537-05:
      DOI: 10.1002/ps.4087
       
  • Applying insecticides through drip irrigation to reduce wireworm
           (Coleoptera: Elateridae) feeding damage in sweet potato
    • Authors: Amber E Arrington; George G Kennedy, Mark R Abney
      Pages: 1133 - 1140
      Abstract: BACKGROUND A 2 year field study was conducted at multiple locations to determine whether insecticides or an entomopathogenic nematode, Steinernema carpocapsae Weiser, applied through drip irrigation in sweet potato reduced wireworm damage when compared with the non‐treated check and/or insecticides applied conventionally. RESULTS Wireworm damage was low in 2012, and there were no differences in the proportion of roots damaged or the severity of damage between treatments. In 2013, a preplant‐incorporated (PPI) application of chlorpyrifos followed by either bifenthrin, imidacloprid, clothianidin, or oxamyl injected through drip irrigation significantly reduced the proportion of wireworm damage as well as the severity of wireworm damage when compared with the non‐treated check. The incidence and severity of wireworm damage in these treatments did not differ significantly from those in the conventional management practice. The PPI application of chlorpyrifos followed by either cyantraniliprole or S. carpocapsae injected through drip irrigation was not significantly different from the non‐treated check in the proportion of wireworm damage; however, both treatments reduced the severity of wireworm damage compared with the non‐treated check. CONCLUSION Applying insecticides through drip irrigation provides an alternative to conventionally applied insecticides. © 2015 Society of Chemical Industry
      PubDate: 2015-10-07T04:58:51.961202-05:
      DOI: 10.1002/ps.4089
       
  • Effects of imidacloprid and clothianidin seed treatments on wheat aphids
           and their natural enemies on winter wheat
    • Authors: Peng Zhang; Xuefeng Zhang, Yunhe Zhao, Yan Wei, Wei Mu, Feng Liu
      Pages: 1141 - 1149
      Abstract: BACKGROUND Wheat aphid (Hemiptera: Aphididae) is one of the major pests of winter wheat and has posed a significant threat to winter wheat production in China. Although neonicotinoid insecticidal seed treatments have been suggested to be a control method, the season‐long efficacy on pests and the impact on their natural enemies are still uncertain. Experiments were conducted to determine the efficacy of imidacloprid and clothianidin on the control of aphids, the number of their natural enemies and the emergence rate and yield of wheat during 2011–2014. RESULTS Imidacloprid and clothianidin seed treatments had no effect on the emergence rate of winter wheat and could prevent yield losses and wheat aphid infestations throughout the winter wheat growing season. Furthermore, their active ingredients were detected in winter wheat leaves up to 200 days after sowing. Imidacloprid and clothianidin seed treatments had no adverse effects on ladybirds, hoverflies or parasitoids, and instead increased the spider–aphid ratios. CONCLUSION Wheat seeds treated with imidacloprid and clothianidin were effective against wheat aphids throughout the winter wheat growing season and reduced the yield loss under field conditions. Imidacloprid and clothianidin seed treatments may be an important component of the integrated management of wheat aphids on winter wheat. © 2015 Society of Chemical Industry
      PubDate: 2015-09-02T03:24:50.846157-05:
      DOI: 10.1002/ps.4090
       
  • The effect of succinate dehydrogenase inhibitor/azole mixtures on
           selection of Zymoseptoria tritici isolates with reduced sensitivity
    • Authors: Hilda Dooley; Michael W Shaw, John Spink, Steven Kildea
      Pages: 1150 - 1159
      Abstract: BACKGROUND Combining fungicides with different modes of action is regarded as one of the most effective means of slowing the selection of resistance. Field trials were used to study the effects of such mixtures on selection for Zymoseptoria tritici with reduced sensitivity to the succinate dehydrogenase inhibitors (SDHIs) and azole fungicides. The SDHI isopyrazam and the azole epoxiconazole were applied individually as solo products, and together in a preformulated mixture. All fungicide treatments were included at both full and half the recommended doses. RESULTS Compared with using epoxiconazole alone, mixing epoxiconazole with isopyrazam led to an increase in epoxiconazole‐sensitive isolates. In contrast, all treatments containing isopyrazam reduced the sensitivity of Z. tritici to isopyrazam compared with those without. Reducing doses to half the recommended rate had no effect on sensitivity of isolates to either active ingredient. In a subgroup of isolates least sensitive to isopyrazam, non‐synonymous mutations were found in the SdhC and SdhD subunits, but their presence was unrelated to sensitivity. CONCLUSION Mixing an azole and SDHI was clearly beneficial for the azole, but not for the SDHI component. This dynamic might change if strains conferring reduced sensitivity to the SDHIs were to arise. © 2015 Society of Chemical Industry
      PubDate: 2015-09-08T04:52:10.88341-05:0
      DOI: 10.1002/ps.4093
       
  • Introduction of the RTA‐Bddsx gene induces female‐specific
           lethal effects in transformed Bactrocera dorsalis (Hendel)
    • Pages: 1160 - 1167
      Abstract: BACKGROUND The oriental fruit fly, Bactrocera dorsalis (Hendel), can reduce fruit production and quality and is considered to be a major insect pest in many Asian countries. A system combining the toxicity of ricin and the alternative RNA splicing properties of doublesex (RTA‐Bddsx) has been proposed that results in differential sexual processing in vitro. A transgenic approach was used in this study to confirm the existence of female‐specific lethal effects in vivo. RESULTS The piggyBac‐based vector PB‐Acp‐CF21‐26, which carries the actin 5C promoter and RTA‐Bddsx, was used to establish transgenic lines. Five surviving male flies (F1) demonstrated the presence of selection marker Ds‐Red(+) throughout their entire bodies following single‐pair mating with wild‐type females, indicating germline transmission. A high percentage of males (59.6–100%) were observed in transformed F3 offspring, and this skewed sex ratio indicated that the female‐lethal effects of the RTA‐Bddsx system were heritable and functioned well in B. dorsalis. Some transformed female flies were observed, and these unexpected results were attributed to the loss of the intact transgene after genomic PCR analyses. CONCLUSION This transgenic study provides direct evidence for the female‐specific lethal effects of RTA‐Bddsx in B. dorsalis and offers a novel and promising approach for the control of B. dorsalis in the future. © 2015 Society of Chemical Industry
      PubDate: 2015-09-07T10:52:10.022954-05:
      DOI: 10.1002/ps.4094
       
  • Can a native rodent species limit the invasive potential of a
           non‐native rodent species in tropical agroforest habitats?
    • Authors: Alexander M Stuart; Colin V Prescott, Grant R Singleton
      Pages: 1168 - 1177
      Abstract: BACKGROUND Little is known about native and non‐native rodent species interactions in complex tropical agroecosystems. We hypothesised that the native non‐pest rodent Rattus everetti may be competitively dominant over the invasive pest rodent Rattus tanezumi within agroforests. We tested this experimentally by using pulse removal for three consecutive months to reduce populations of R. everetti in agroforest habitat, and assessed over 6 months the response of R. tanezumi and other rodent species. RESULTS Following removal, R. everetti individuals rapidly immigrated into removal sites. At the end of the study period, R. tanezumi were larger and there was a significant shift in their microhabitat use with respect to the use of ground vegetation cover following the perturbation of R. everetti. Irrespective of treatment, R. tanezumi selected microhabitat with less tree canopy cover, indicative of severely disturbed habitat, whereas R. everetti selected microhabitat with a dense canopy. CONCLUSION Our results suggest that sustained habitat disturbance in agroforests favours R. tanezumi, while the regeneration of agroforests towards a more natural state would favour native species and may reduce pest pressure in adjacent crops. In addition, the rapid recolonisation of R. everetti suggests this species would be able to recover from non‐target impacts of short‐term rodent pest control. © 2015 Society of Chemical Industry
      PubDate: 2015-09-08T04:34:04.317913-05:
      DOI: 10.1002/ps.4095
       
  • Simulating the fate and transport of nursery‐box‐applied
           pesticide in rice paddy fields
    • Authors: Julien Boulange; Dang Quoc Thuyet, Piyanuch Jaikaew, Hirozumi Watanabe
      Pages: 1178 - 1186
      Abstract: BACKGROUND The Pesticide Concentration in a Paddy Field model (PCPF‐1) was modified by adding a root zone compartment to simulate nursery‐box‐applied (NB‐applied) pesticide. The PCPF‐NB model was validated for predicting the concentrations of NB‐applied fipronil and imidacloprid in rice paddy fields using two treatment methods: before transplanting (BT) and at sowing (AS). Uncertainty and sensitivity analyses were used to evaluate the robustness of the concentrations predicted by the model. RESULTS The hourly predicted concentrations of imidacloprid and fipronil were accurate in both paddy water and 1 cm deep paddy soil. The coefficient of determination and Nash–Sutcliffe model efficiency were greater than 0.87 and 0.60 respectively. The 95th percentiles of the predicted concentrations of fipronil and imidacloprid indicated that the influence of input uncertainty was minor in paddy water but important in paddy soil. The pesticide deposition rate and the desorption rate from the root zone were identified to be the major contributors to the variation in the predicted concentrations in paddy water and soil. CONCLUSION The PCPF‐NB model was validated for predicting the fate and transport of NB‐applied fipronil and imidacloprid using the BT and AS treatment methods. © 2015 Society of Chemical Industry
      PubDate: 2015-09-16T03:13:10.400793-05:
      DOI: 10.1002/ps.4096
       
  • Comparison of predicted pesticide concentrations in groundwater from
           SCI‐GROW and PRZM‐GW models with historical monitoring data
    • Authors: Tammara L Estes; Naresh Pai, Michael F Winchell
      Pages: 1187 - 1201
      Abstract: BACKGROUND A key factor in the human health risk assessment process for the registration of pesticides by the US Environmental Protection Agency (EPA) is an estimate of pesticide concentrations in groundwater used for drinking water. From 1997 to 2011, these estimates were obtained from the EPA empirical model SCI‐GROW. Since 2012, these estimates have been obtained from the EPA deterministic model PRZM‐GW, which has resulted in a significant increase in estimated groundwater concentrations for many pesticides. RESULTS Historical groundwater monitoring data from the National Ambient Water Quality Assessment (NAWQA) Program (1991–2014) were compared with predicted groundwater concentrations from both SCI‐GROW (v.2.3) and PRZM‐GW (v.1.07) for 66 different pesticides of varying environmental fate properties. The pesticide environmental fate parameters associated with over‐ and underprediction of groundwater concentrations by the two models were evaluated. CONCLUSION In general, SCI‐GROW2.3 predicted groundwater concentrations were close to maximum historically observed groundwater concentrations. However, for pesticides with soil organic carbon content values below 1000 L kg−1 and no simulated hydrolysis, PRZM‐GW overpredicted, often by greater than 100 ppb. © 2015 Society of Chemical Industry
      PubDate: 2015-09-11T03:27:47.124865-05:
      DOI: 10.1002/ps.4097
       
  • Toxicity of Lavandula angustifolia oil constituents and spray formulations
           to insecticide‐susceptible and pyrethroid‐resistant Plutella
           xylostella and its endoparasitoid Cotesia glomerata
    • Pages: 1202 - 1210
      Abstract: BACKGROUND Plutella xylostella is one of the most serious insect pests of cruciferous crops. This study was conducted to determine the toxicity of 21 constituents from Lavandula angustifolia essential oil (LA‐EO) and another 16 previously known LA‐EO constituents and the toxicity of six experimental spray formulations containing the oil (1–6 g L−1 sprays) to susceptible KS‐PX and pyrethroid‐resistant JJ‐PX P. xylostella larvae, as well as to its endoparasitoid Cotesia glomerata adults. RESULTS Linalool and linalool oxide (LC50 = 0.016 mg cm−3) were the most toxic fumigant compounds and were 10.7‐fold less toxic than dichlorvos to KS‐PX larvae. Either residual or fumigant toxicity of these compounds was almost identical against larvae from either of the two strains. Against C. glomerata, dichlorvos (LC50 = 7 × 10−6 mg cm−3) was the most toxic insecticide. LA‐EO was ∼1430 times less toxic than dichlorvos. The oil applied as 6 g L−1 spray and emamectin benzoate 21.5 g L−1 emulsifiable concentrate provided 100% mortality against larvae from either of the two strains. CONCLUSION Reasonable P. xylostella control in greenhouses can be achieved by a spray formulation containing the 6 g L−1 oil as potential contact‐action fumigant. © 2015 Society of Chemical Industry
      PubDate: 2015-09-09T04:16:57.535214-05:
      DOI: 10.1002/ps.4098
       
  • Detection of the F129L mutation in the cytochrome b gene in Phakopsora
           pachyrhizi
    • Authors: Ana C Klosowski; Louise L May De Mio, Simone Miessner, Ronaldo Rodrigues, Gerd Stammler
      Pages: 1211 - 1215
      Abstract: BACKGROUND Asian soybean rust, caused by Phakopsora pachyrhizi, is mostly controlled by demethylation inhibitor (DMI) and quinone outside inhibitor (QoI) fungicides. Mutations in the cytochrome b (CYTB) gene can lead to pathogen resistance to QoIs. The occurrence of the mutations in codons 129, 137 and 143 in the CYTB gene was investigated, and a pyrosequencing assay was developed for rapid and quantitative detection of the F129L mutation. RESULTS Molecular analysis of the CYTB gene showed the presence of the F129L mutation in field samples and monouredinial isolates, while other mutations (G143A and G137R) were not found. The pyrosequencing was an effective method for quantitative detection of the F129L mutation, and many of the P. pachyrhizi samples showed high frequency of F129L. CONCLUSION This is the first report of the occurrence of the F129L mutation in P. pachyrhizi. The practical relevance of this mutation for field efficacy of QoIs needs further investigation. © 2015 Society of Chemical Industry
      PubDate: 2015-09-28T08:24:37.879514-05:
      DOI: 10.1002/ps.4099
       
  • Filtration system performance cleaning exhaust air of pneumatic maize seed
           drills
    • Authors: Marco Manzone; Mario Tamagnone
      Pages: 1216 - 1221
      Abstract: BACKGROUND In the agricultural sector, toxic substances can be released into the atmosphere. In recent years, Europe has encountered a significant environmental issue related to the dispersion of pesticides during maize seeding, especially when performed with pneumatic seed drills. This phenomenon can be very dangerous for insects, as the dispersed dust contains pesticides (insecticides, fungicides, etc.) used to dress maize seeds. On the basis of these considerations, experimental tests have been carried out using a filtration system to clean the airflow that exits from the fan of pneumatic maize seed drills. RESULTS The tested filtration system does not interfere with the seeding quality because the vacuum level observed within the filtration system assembled on the seeder (5.7 kPa) is 27% higher than the correct vacuum level to guarantee good seeding quality (4.2 kPa). In addition, it enables a reduction in the risk of environmental contamination, as no dust deposits were found at different distances from the machine. CONCLUSION The use of a filtration system shows advantages in terms of environmental and operator safety because dangerous materials are contained in the filter case, thus avoiding contamination of neighbouring areas and the machinery used (tractor and seed drill). © 2015 Society of Chemical Industry
      PubDate: 2015-09-28T08:28:12.274068-05:
      DOI: 10.1002/ps.4101
       
  • Diversity of bacterial communities in the midgut of Bactrocera cucurbitae
           
    • Authors: Ashok B Hadapad; Chandra S Prabhakar, Snehal C Chandekar, Jyoti Tripathi, Ramesh S Hire
      Pages: 1222 - 1230
      Abstract: BACKGROUND The microbiota plays an important role in insect development and fitness. Understanding the gut microbiota composition is essential for the development of pest management strategies. Midgut bacteria were isolated from nine wild B. cucurbitae populations collected from different agroecological zones of India. These isolates were further studied for attractant potential of fruit fly adults, and the chemical constituents in the supernatants of gut bacteria were analysed. RESULTS Twenty‐six bacterial isolates belonging to the families Enterobacteriaceae, Bacillaceae, Micrococcaceae and Staphylococcaceae were isolated and identified on the basis of 16S rRNA gene sequence analysis. The dominant species in the midgut of melon fly were from the genera Enterobacter (34.6%), Klebsiella (19.2%), Citrobacter (7.7%), Bacillus (15.4%) and Providencia (7.7%), and 3.8% each of Micrococcus, Staphylococcus, Leclercia and Exiguobacterium. Bactrocera cucurbitae and B. dorsalis adults were significantly attracted to bacterial whole cell cultures and their supernatants in the fruit fly attraction bioassays. Bacillus cereus, Enterobacter, Klebsiella, Citrobacter and Providencia species attracted both male and females of Bactrocera species. The supernatants of Klebsiella, Citrobacter and Providencia species attracted a significantly greater number of females than males. The most abundant chemical constituents in supernatants of K. oxytoca and C. freundii were 3‐methyl‐1‐butanol, 2‐phenylethanol, butyl isocyanatoacetate, 2‐methyl‐1‐propanol and 3‐hydroxy‐2‐butanone, as identified by gas chromatography–mass spectrometry. CONCLUSIONS The bacterial endosymbionts associated with melon fly exhibited attractant potential which could facilitate eco‐friendly insect control strategies. © 2015 Society of Chemical Industry
      PubDate: 2015-09-25T07:39:17.214776-05:
      DOI: 10.1002/ps.4102
       
  • Knockdown of juvenile hormone acid methyl transferase severely affects the
           performance of Leptinotarsa decemlineata (Say) larvae and adults
    • Pages: 1231 - 1241
      Abstract: BACKGROUND Juvenile hormone (JH) plays a critical role in the regulation of metamorphosis in Leptinotarsa decemlineata, a notorious defoliator of potato. JH acid methyltransferase (JHAMT) is involved in one of the final steps of JH biosynthesis. RESULTS A putative JHAMT cDNA (LdJHAMT) was cloned. Two double‐stranded RNAs (dsRNAs) (dsJHAMT1 and dsJHAMT2) against LdJHAMT were constructed and bacterially expressed. Experiments were conducted to investigate the effectiveness of RNAi in both second‐ and fourth‐instar larvae. Dietary introduction of dsJHAMT1 and dsJHAMT2 successfully knocked down the target gene, lowered JH titre in the haemolymph and reduced the transcript of Krüppel homologue 1 gene. Ingestion of dsJHAMT caused larval death and weight loss, shortened larval developmental period and impaired pupation. Moreover, the dsJHAMT‐fed pupae exhibited lower adult emergence rates. The resulting adults weighed an average of 50 mg less than the control group, and the females did not deposit eggs. Application of pyriproxyfen to the dsJHAMT‐fed insects rescued all the negative effects. CONCLUSIONS LdJHAMT expresses functional JHAMT enzyme. The RNAi targeting LdJHAMT could be used for control of L. decemlineata. © 2015 Society of Chemical Industry
      PubDate: 2015-09-25T07:42:31.134713-05:
      DOI: 10.1002/ps.4103
       
  • Efficacy of essential oil of Piper aduncum against nymphs and adults of
           Diaphorina citri
    • Pages: 1242 - 1249
      Abstract: BACKGROUND Insecticide application is the main way to control Diaphorina citri. However, it causes environmental contamination, has a negative impact on beneficial organisms and leads to psyllid resistance. The essential oil of Piper aduncum has low toxicity towards the environment and contains dillapiol, which has proven to be effective against several crop pests. Here, we studied its efficacy against nymphs and adults of D. citri under laboratory conditions. Oils with three concentrations of dillapiol (69.3, 79.9 and 85.4%) at 0.5, 0.75 and 1.0% dilutions plus 0.025% adjuvant were tested. RESULTS All treatments caused 90–100% mortality in nymphs. Topical treatments with oil containing 79.9 and 85.4% dillapiol at 0.75% and 1% dilutions were effective (mortality ≥80%) in adults. However, the essential oil showed no residual activity against adults (mortality ≤30%). CONCLUSIONS Dillapiol‐rich oil is a promising compound for D. citri control. © 2015 Society of Chemical Industry
      PubDate: 2015-10-12T03:43:16.531105-05:
      DOI: 10.1002/ps.4143
       
  • Impact of neonicotinoid seed treatment of cotton on the cotton leafhopper,
           Amrasca devastans (Hemiptera: Cicadellidae), and its natural enemies
    • Authors: Rabia Saeed; Muhammad Razaq, Ian CW Hardy
      Pages: 1260 - 1267
      Abstract: BACKGROUND Neonicotinoid seed treatments suppress populations of pest insects efficiently and can enhance crop growth, but they may have negative effects on beneficial arthropods. We evaluated the effects of either imidacloprid or thiamethoxam on the abundances of a sucking pest, the cotton leafhopper (Amrasca devastans), and its arthropod predators under field conditions. We also evaluated the impact of seed treatment on transgenic cotton plant growth, with pests and natural enemies present or absent. RESULTS Imidacloprid and thiamethoxam reduced pest abundance, with greater effects when dosages were higher. Treatment at recommended doses delayed the pest in reaching the economic damage threshold by around 10–15 days (thiamethoxam) and 20 days (imidacloprid). Recommended doses also enhanced plant growth under all tested conditions; growth is affected directly as well as via pest suppression. Neonicotinoid applications reduced abundance of beneficial arthropods, with lower populations after higher doses, but negative effects of imidacloprid were not apparent unless the manufacturer‐recommended dose was exceeded. CONCLUSION Imidacloprid applied at the recommended dose of 5 g kg−1 seed is effective against A. devastans and appears to be safer than thiamethoxam for natural enemies, and also enhances plant growth directly. We caution, however, that possible sublethal negative effects on individual beneficial arthropods were not evaluated. © 2015 Society of Chemical Industry
      PubDate: 2015-10-05T07:53:15.01607-05:0
      DOI: 10.1002/ps.4146
       
 
 
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