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Journal Cover Pest Management Science
  [SJR: 1.258]   [H-I: 86]   [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  [1609 journals]
  • Characterisation of Ramularia collo‐cygni laboratory mutants resistant
           to Succinate Dehydrogenase Inhibitors
    • Authors: Marta J Piotrowska; James M Fountaine, Richard A Ennos, Maciej Kaczmarek, Fiona J Burnett
      Abstract: BACKGROUND Ramularia collo‐cygni (Rcc) is responsible for Ramularia leaf spot (RLS), a foliar disease of barley contributing to serious economic losses. Protection against the disease has been almost exclusively based on fungicide applications, including Succinate Dehydrogenase Inhibitors (SDHIs). In 2015 the first field isolates of Rcc with reduced sensitivity to SDHIs were recorded in some European countries. In this study we established baseline sensitivity of Rcc to SDHIs in the UK and characterised mutations correlating with resistance to SDHIs in UV‐generated mutants. RESULTS Five SDHI resistant isolates were generated by UV mutagenesis. In four of these mutants a single amino acid change in a target succinate dehydrogenase (Sdh) protein was associated with decrease in sensitivity to SDHIs. Three of these mutations were stably inherited in the absence of SDHI fungicide and resistant isolates did not demonstrate a fitness penalty. There were no detectable declines in sensitivity in field populations in years 2010–2012 in the UK. CONCLUSIONS SDHIs remained effective in controlling Rcc in the UK in years 2010–2012. However given that the first isolates of Rcc with reduced sensitivity appeared in other European countries in 2015, robust anti‐resistance strategies need to be continuously implemented to maintain effective disease control.
      PubDate: 2016-09-19T09:50:32.905348-05:
      DOI: 10.1002/ps.4442
       
  • Overexpression of TAT‐PTD‐diapause hormone fusion protein in tobacco
           and it effect on larval development of Helicoverpa armigera (Lepidoptera:
           Noctuidae)
    • Authors: Zhou Zhou; Yongli Li, Chunyan Yuan, Daniel Doucet, Yongan Zhang, Liangjian Qu
      Abstract: BACKGROUND The diapause hormone (DH) has been shown to either induce or terminate diapause depending on the insect species. In a previous study we demonstrated that the DH from Clostera anastomosis (caDH) has biological activity in Helicoverpa armigera, which prompted us to examine the potential growth‐inhibiting or antiherbivory effects of the TAT‐caDH fusion protein when expressed in transgenic plants. RESULTS In this study, we produced transgenic tobacco plants expressing either the TAT‐caDH protein, or a TAT‐caDH‐eGFP fusion version that allows tracking of the fluorescent protein in plant tissues. Our results indicate that H. armigera larvae feeding on transgenic tobacco expressing TAT‐caDH exhibited a significantly reduced survival rate and weight gain. However, larvae feeding on transgenic tobacco expressing TAT‐caDH‐eGFP were unaffected. While fusion of the eGFP gene influenced the bioactivity of caDH in larvae, TAT‐caDH‐eGFP can still penetrate the insect midgut cell membrane. CONCLUSION TAT‐caDH increases DH stability in oral delivery. Our results may help in targeting DH‐dependent physiological processes in insects for improving herbivore tolerance in economically important crops.
      PubDate: 2016-09-19T09:40:20.718787-05:
      DOI: 10.1002/ps.4443
       
  • Phorate can reverse P450 metabolism‐based herbicide resistance in
           Lolium rigidum
    • Authors: Roberto Busi; Todd Adam Gaines, Stephen Powles
      Abstract: BACKGROUND Organo‐phosphate insecticides can inhibit specific cytochrome P450 enzymes involved in metabolic herbicide resistance mechanisms leading to synergistic interactions between the insecticide and the herbicide. In this study we report synergistic versus antagonistic interactions between the organo‐phosphate insecticide phorate and five different herbicides observed in a population of multiple herbicide‐resistant Lolium rigidum. RESULTS Phorate synergized with three different herbicide modes of action enhancing the activity of the ALS‐inhibitor chlorsulfuron (60% LD50 reduction), the VLCFAE‐inhibitor pyroxasulfone (40% LD50 reduction), and the mitosis‐inhibitor trifluralin (70% LD50 reduction). Conversely, phorate antagonized the two thiocarbamate herbicides prosulfocarb (7‐fold LD50 increase) and triallate (11‐fold LD50 increase). CONCLUSION We report the selective reversal of P450‐mediated metabolic multiple‐resistance to chlorsulfuron and trifluralin in the grass weed L. rigidum by synergistic interaction with the insecticide phorate and discuss the putative mechanistic basis. This research should encourage diversity in herbicide use patterns for weed control as part of a long‐term integrated management effort to reduce the risk of selection of metabolism‐based multiple herbicide resistance in L. rigidum.
      PubDate: 2016-09-19T09:35:22.019313-05:
      DOI: 10.1002/ps.4441
       
  • Substitutions in Spodoptera exigua Topoisomerase I modulate its relaxation
           activity and camptothecin sensitivity
    • Authors: Pei Zhang; Lan Zhang, Yanning Zhang, Liangang Mao, Hongyun Jiang
      Abstract: BACKGROUND Topoisomerase I (Top I) is referred as the cellular target of the camptothecins (CPTs) which are now being explored as potential pesticides for insect control. Three amino acid substitutions including L530P, A653T and S729T in Top Is of insects were found in our previous studies. In order to investigate the effect of these three substitutions, the comparative analysis was conducted between the wild type and mutant Top Is in Spodoptera exigua Hübner. RESULTS The optimal salt concentration of A653T and S729T was 150 mM consistent with that of the wild type Top I. While, the mutant L530P showed the maximum relaxation activity at a lower KCl concentration (100 mM). The mutated L530P and A653T Top Is showed higher relaxation efficiency due to the increased relaxation velocity toward the negatively supercoiled plasmid pBR322 DNA, which rendered L530P and A653T resistance to CPTs. While, mutant S729T exhibited sensitivity to CPTs as a result of a decreased relaxation activity toward plasmid pBR322 DNA. CONCLUSIONS These results suggested that the polymorphism in Top I of insects was related to the biological activity of CPTs, which provided the basic information for the reasonable usage of CPTs to control insect pests.
      PubDate: 2016-09-19T09:29:40.022106-05:
      DOI: 10.1002/ps.4440
       
  • Inhibition of early development stages of rust fungi by the two fungal
           metabolites cyclopaldic acid and epi‐epoformin
    • Authors: Eleonora Barilli; Alessio Cimmino, Marco Masi, Marco Evidente, Diego Rubiales, Antonio Evidente
      Abstract: BACKGROUND Rusts are a noxious group of plant diseases affecting major economically important crops. Crop protection is largely based on chemical control. There is a renewed interest in the discovery of natural products as alternatives to synthetic fungicides for control. In this study we tested two fungal metabolites, namely cyclopaldic acid and epi‐epoformin, for their effectiveness in reducing early stages of development of two major rusts fungi from the genera Puccinia and Uromyces, P. triticina and U. pisi. Spore germination and appressoria formation were assessed on pre‐treated detached leaves under controlled conditions. Cyclopaldic acid and epi‐epofomin were also tested in infected plants in order to evaluate the level of control achieved by treatments both before and after inoculation. RESULTS Cyclopaldic acid and epi‐epoformin were strongly effective in inhibiting fungal germination and penetration of both rust species studied. This effect was not dose‐dependent. These results were further confirmed in planta by spraying the metabolites on plants leaves which reduced fungal developmental of U. pisi and P. triticina at values comparable to those obtained by application of the fungicide. CONCLUSION Our results further demonstrate the potential of fungal metabolites as natural alternatives to synthetic fungicides for the control of crop pathogens of economic importance as rusts.
      PubDate: 2016-09-14T04:05:42.680358-05:
      DOI: 10.1002/ps.4438
       
  • Insecticide resistance and size assortative mating in females of the maize
           weevil (Sitophilus zeamais)
    • Abstract: BACKGROUND Random mating is a common assumption in studies of insecticide resistance evolution, but seldom tested despite its potential consequences. Therefore, the existing evidence of female choice and insecticide resistance in populations of the maize weevil (Sitophilus zeamais), a key pest of stored cereals, led to the assessment of mating preferences and its association with insecticide resistance in this species. RESULTS Mixed lines of a maize weevil colony were established from field‐collected populations, which after five months of natural breeding were selected for deltamethrin resistance for five generations reaching over 100‐fold resistance. Mating preference was significantly based on the partner size, measured as body mass (χ2 = 5.83, df = 1, P = 0.016). Susceptible females preferred heavier males for mating (χ2 = 5.83, df = 1, P = 0.015), trait that was more frequently associated with deltamethrin resistance (χ2 = 7.38, df = 1, P = 0.007). Deltamethrin resistance compromised daily fertility, although the reduced offspring production observed in matings between susceptible females and resistant males were negligible. CONCLUSION Susceptible female weevils prefer larger (and heavier) males to mate, trait associated with deltamethrin resistance, favoring the maintenance and spread of the resistant phenotype in the population.
      PubDate: 2016-09-14T03:55:31.426955-05:
      DOI: 10.1002/ps.4437
       
  • Monitoring and mechanisms of insecticide resistance in Chilo suppressalis
           (Lepidoptera: Crambidae) with special reference to diamides
    • Abstract: BACKGROUND The rice stem borer, Chilo suppressalis Walker (Lepidoptera: Crambidae) is one of the most economically important pests of rice in Asia. Chemical control remains the most efficient primary means for controlling this pest. RESULTS Significant variations among field populations to seven insecticides were observed. The populations exhibited LC50 values that ranged between 0.605 ‐ 108.088 mg a.i L−1 for chlorantraniliprole and 0.046 ‐ 3.919 mg a.i L−1 for flubendiamide. YY14 population collected from Yuyao in Zhejiang province at 2014 showed moderate resistance level to two diamides, i.e., up to 77.6‐ and 42.6‐fold for chlorantraniliprole and flubendiamide, respectively. Synergism tests and biochemical assays showed no obvious correlations between diamides resistance and three detoxifying enzymes. Sequence comparison of ryanodine receptor gene between YY14 resistant population and susceptible population revealed that a glycine to glutamic acid substitution (G4910E) was presented in the YY14 population. CONCLUSION G4910E mutation might be involved in the resistance evolution of C. suppressalis to the diamides. The appropriate insecticide resistance management program should be established to maintain the effectiveness of the insecticides and to ensure sustainable management.
      PubDate: 2016-09-14T03:47:18.459542-05:
      DOI: 10.1002/ps.4439
       
  • A negative association between bromadiolone exposure and nestling body
           condition in common kestrels: management implications for vole outbreaks
    • Abstract: BACKGROUND Vole outbreaks have been extensively described along with their impacts on humans, particularly in agricultural areas. The use of rodenticides is a common legal practice to minimise crop damage induced by high vole density for biocidal use. However, rodenticides can have negative direct and indirect impacts on non‐target species that feed on voles. We studied whether the use of a second generation anticoagulant rodenticide, bromadiolone, can be detected in the blood of fledglings of wild common kestrels Falco tinnunculus in two areas of central Spain, exploring its possible indirect effects. RESULTS We found that 16.9% of fledgling had detectable concentration of bromadiolone in their blood, with an average concentration of 0.248 ± 0.023 ng/mL. Fledglings with bromadiolone in their blood, regardless of the concentration, had 6.7% lower body mass than those without detectable bromadiolone. CONCLUSION The use of bromadiolone was detectable in the blood of alive non‐target species. Detected bromadiolone in blood may reduce body condition of nestlings, potentially reducing their fitness. The source of bromadiolone found in nestlings need to be determined in future studies to derive accurate management advice. However, we urge the discontinuation of official SGAR distribution to farmers and their use in agrarian lands to minimise damage of voles on crops, particularly where common kestrel breed and encourage the use of alternative effective practices.
      PubDate: 2016-09-12T04:55:28.009228-05:
      DOI: 10.1002/ps.4435
       
  • Detection of the cytochrome b mutation G143A in Irish Rhynchosporium
           commune populations using targeted 454 sequencing
    • Abstract: BACKGROUND Rhynchosporium commune is a major fungal pathogen of barley crops and the application of fungicides, such as Quinone outside inhibitors (QoI’s), plays an important role in crop disease control. The genetic mechanisms linked to QoI resistance have been identified in the cytochrome b gene, with QoI resistance conferred by the G143A substitution. The objective of this study was to develop a high throughput molecular assay to detect and identify mutations associated with QoI resistance within the Irish R. commune population. RESULTS Leaf lesions of R. commune sampled from 74 sites, during 2009‐2014, and isolates from 2006 and 2007 were screened for non‐synonymous mutations of the cytochrome b gene using 454 targeted sequencing. The presence of the G143A substitution was confirmed in R. commune samples in one site in 2013 and in four sites in 2014, however the frequency of the substitution in these samples was low (2‐18%). 454 sequencing results were confirmed though PCR‐RFLP and Sanger sequencing. CONCLUSION The molecular assay which has been applied to this monitoring programme has shown that the application of 454 next generation sequencing offers the potential for high throughput and accurate characterisation of non‐synonymous mutations associated with fungicide resistance in a crop pathogen.
      PubDate: 2016-09-12T04:06:08.607765-05:
      DOI: 10.1002/ps.4434
       
  • Evaluation of field resistance to Striga hermonthica [Del.] Benth. in
           Sorghum bicolor [L.] Moench. The relationship with strigolactones
    • Authors: Nasreldin M. Ahmed; Tatsiana Charnikhova, Evert J. Bakker, Aad van Ast, Abdelgabar G.T. Babiker, Harro J. Bouwmeester
      Abstract: BACKGROUND Significant losses in sorghum biomass and grain yield occur in sub‐Saharan Africa due to infection by the root parasitic weed Striga hermonthica [Del.] Benth. One strategy to avoid these losses is to adopt resistant crop varieties. To further delineate the role of germination stimulants in resistance we conducted a field experiment employing six sorghum genotypes, in eastern Sudan, and in parallel analysed the strigolactone levels in the root exudates of these genotypes under controlled conditions in Wageningen. RESULTS The root exudates of these genotypes displayed large differences in strigolactone composition and Striga germination inducing activity. Korokollow, Fakimustahi and Wadfahel exuded the highest amounts of 5‐deoxystrigol. Fakimustahi was by far the highest sorgomol producer and Wadbaco and SRN39 produced the highest amount of orobanchol. The concentration of 5‐deoxystrigol in the root exudate showed a significant positive correlation with in vitro Striga germination and was positively associated with Striga infection in the field experiments, while orobanchol, on the other hand, was negatively associated with Striga infection in the field experiments. CONCLUSION For the first time a close association is reported between strigolactone levels, analysed under laboratory conditions, and Striga infection in the field in sorghum genotypes. These genotypes may be used to further study this resistance mechanism and for the introgression of the low germination trait in other sorghum varieties to breed for a strigolactone composition with low stimulant activity. The use of such improved varieties in combination with other Striga management tools could possibly alleviate the current Striga problem in the African continent.
      PubDate: 2016-09-09T07:17:16.014851-05:
      DOI: 10.1002/ps.4426
       
  • ELECTROSTATIC SPRAYING IN THE CHEMICAL CONTROL OF Triozoida limbata
           (ENDERLEIN) (HEMIPTERA: TRIOZIDAE) IN GUAVA TREES (Psidium guajava L.)
    • Abstract: BACKGROUND Due to the difficulty in reaching targets during pesticide applications on guava trees, it is important to evaluate new technologies that may improve pest management. In electrostatic spraying, an electric force is added to the droplets to control their movements such that they are efficiently directed to the target. The present study evaluated the performance of electrostatic and non‐electrostatic spraying in the control of the guava psyllid, the deposition of the spray mixture on the leaves, and the losses to the soil. RESULTS The deposition of the spray mixture was up to two times greater when using electrostatic spraying in comparison with non‐electrostatic application. The losses of the spray mixture to the soil were up to four times smaller with the electrostatic spraying. Electrostatic had better control of the psyllid. CONCLUSION It was possible to reduce the volume rate of application with electrostatic spraying without adversely affecting the control of the guava psyllid.
      PubDate: 2016-09-08T08:45:45.603231-05:
      DOI: 10.1002/ps.4433
       
  • Active saponins from root of Pueraria peduncularis (Grah. ex Benth.)
           Benth. and their molluscicidal effects on Pomacea canaliculata
    • Authors: ChunPing Yang; Min Zhang, Bo Lei, GuoShu Gong, GuiZhou Yue, XiaoLi Chang, XiaoFang Sun, Yue Tian, HuaBao Chen
      Abstract: BACKGROUND Pueraria peduncularis (Grah. ex Benth.) Benth., which belongs to the Leguminosae family, exhibits resistance to many crop pests in agricultural production. Pomacea canaliculata is an important invasive snail in rice fields and causes severe yield losses. To evaluate the toxicity of P. peduncularis to P. canaliculata, in this study, the molluscicidal activity of root extracts of P. peduncularis was tested against P. canaliculata, and the active compounds were isolated, and the structures of these compounds were analyzed on the basis of using nuclear magnetic resonance (NMR) analysis and mass spectral analysis. RESULTS Our results showed that the molluscicidal activity of the root crude extract differed between P. canaliculata with different shell diameters after treatment for 72 h. The median lethal concentration (LC50) was 5.511 mg · L−1 against snails with1.5 ± 0.2 cm in diameter and 12.383 mg · L−1 against snails with 2.5 ± 0.2 cm in diameter. Furthermore, two active ingredients isolated from root methanol extracts were identified as pedunsaponin A and pedunsaponin C. Both pedunsaponin A and C showed strong molluscicidal activities, with LC50 values of 3.893 mg · L−1 and 4.252 mg · L−1, respectively, against snails with shell diameters of 1.5 ± 0.2 cm after treatment for 72 h. CONCLUSION Pueraria peduncularis extracts exhibit high molluscicidal activity and have great potential value for exploring a molluscicide to control Pomacea canaliculata.
      PubDate: 2016-09-08T08:45:42.622886-05:
      DOI: 10.1002/ps.4432
       
  • Discovery of the aryl heterocyclic amine (AHA) insecticides: Synthesis,
           insecticidal activity, field results, mode of action and bioavailability
           of a leading field candidate
    • Authors: William H Dent; Mark A Pobanz, Chaoxian Geng, Thomas C Sparks, Gerald B Watson, Theodore J Letherer, Kenneth W Beavers, Cathy D Young, Yelena A Adelfinskaya, Ronald R Ross, Greg Whiteker, James Renga
      Abstract: BACKGROUND Gamma‐amino butyric acid (GABA) antagonists are proven targets for control of Lepidopteran and other pests. New heterocyclic compounds with high insecticidal activity were discovered using a competitive‐intelligence inspired scaffold hopping approach to generate analogs of fipronil, a known GABA antagonist. These novel aryl heterocyclic amines (AHA’s) displayed broad spectrum activity on a number of chewing insect pests. RESULTS Through >370 modifications of the core AHA structure, a 7‐pyrazolopyridine lead molecule was found to exhibit much improved activity on a number of insect pests. In field trial studies, its performance was 2 – 4x lower than commercial standards and also appeared to be species dependent with good activity seen for larvae of Spodoptera exigua, but inactive on larvae of Trichoplusia ni. CONCLUSION An extensive investigational biology effort demonstrated that these AHA analogs appear to have multiple modes of action including GABA receptor antagonism and mitopotential or uncoupler activity. The limited capability in larvae of T. ni to convert the lead molecule to its associated open form correlates with the low toxicity of the lead molecule in this species. This work has provided information that could aid investigations of novel GABA antagonists.
      PubDate: 2016-09-08T08:25:19.649081-05:
      DOI: 10.1002/ps.4431
       
  • Biological activity of Myrtaceae plant essential oils and their major
           components against Drosophila suzukii (Diptera: Drosophilidae)
    • Authors: Miyeon Jang; Junheon Kim, Kyungjae Andrew Yoon, Si Hyeock Lee, Chung Gyoo Park
      Abstract: Background The spotted wing drosophila (SWD), Drosophila suzukii (Matsumura), is a globally invasive and serious pest of numerous soft‐skinned fruit crops. Assessments were made of fumigant and contact toxicities of 12 Myrtaceae plant essential oils (EOs) and their components. For determining the mode of action of major components of active EOs, their activities against acetylcholinesterase (AChE) and Glutathione S‐transferase (GST) were also assessed. Results Strong fumigant and contact toxicities were observed from EOs of Eucalyptus citriodora and Melaleuca teretifolia. The main components of E. citriodora were citronellal and isopulegol, whereas those of M. teretifolia were neral and geranial. Geranial showed the strongest fumigant activity followed by citronellal or neral, M. teretifolia EO, isopulegol, and E. citriodora EO. In contact toxicity assay, Geranial also exhibited the strongest insecticidal activity followed by neral or M. teretifolia EO, citronellol, citronellal, isopulegol, and E. citriodora EO. Among the major components, all compounds showed low AChE inhibitory activity, while neral and geranial showed GST inhibitory activity against SWD. Conclusion Myrtaceae plant EOs and their components have an excellent potential for being used in the control of SWD adult and could be useful in the development of more effective natural compounds as alternatives to synthetic pesticides.
      PubDate: 2016-09-08T07:35:41.348074-05:
      DOI: 10.1002/ps.4430
       
  • Impact of sesquiterpenes from Inula racemosa (Asteraceae) on growth,
           development and nutrition of Spodoptera litura (Lepidoptera:Noctuidae)
    • Authors: Mandeep Kaur; Rakesh Kumar, Deep Patel Upendrabhai, Inder Pal Singh, Sanehdeep Kaur
      Abstract: BACKGROUND The use of botanical pesticides for protecting crops from insect pests has assumed greater importance all over the world due to growing awareness of harmful effects of indiscriminate use of synthetic pesticides. Inula racemosa Hook. f. (Asteraceae), a medicinally important perennial herb is rich in sesquiterpenes with many biological activities. The present studies were conducted with the objective to evaluate the sesquiterpenes isolated from I. racemosa for insecticidal activity against Spodoptera litura (F.). RESULTS Alantolactone and isoalantolactone isolated from I. racemosa, exerted growth inhibitory effects on S. litura. Addition of both the sesquiterpenes to larval diet extended the development period and reduced pupation as well as adult emergence. The dietary utilization experiments on 3rd instar larvae of S. litura revealed reduction in consumption and growth rates of larvae as well as efficiency of conversion of ingested and digested food due to alantolactone and isoalantolactone. CONCLUSION The root extract of I. racemosa which is rich in two sesquiterpenes i.e. alantolactone and isoalantolactone, has the potential for management of S. litura. However, there is need to understand the specific mechanism of action of these compounds.
      PubDate: 2016-09-08T07:31:16.575324-05:
      DOI: 10.1002/ps.4429
       
  • Evaluating a filtering and recirculating system to reduce dust drift in
           simulated sowing of dressed seed and abraded dust particle characteristics
           
    • Authors: Marcello Biocca; Daniele Pochi, Roberto Fanigliulo, Pietro Gallo, Patrizio Pulcini, Francesca Marcovecchio, Cinzia Perrino
      Abstract: BACKGROUND The pneumatic precision drills used in maize sowing can release dust due to abrasion of dressed seed; the drift of dust containing insecticide active ingredients (a.i.) are harmful to honeybees. Therefore, we developed a device for drills, which uses partial recirculation and filtration of the air by means of an anti‐pollen and an electrostatic filter. RESULTS Tests were carried out by simulating sowing of seed treated with imidacloprid, thiamethoxam, clothianidin and fipronil. Dust released by the drill in different configurations were analyzed to assess its mass and a.i. concentration, size distribution and particle number concentration. In general, particles with a diameter lower than 2.5 µm (Particulate Matter ‐ PM2.5) and 10 µm (PM10), represent about 40% and 75% of the total dust mass, respectively. The finest size fraction (
      PubDate: 2016-09-08T07:31:14.403767-05:
      DOI: 10.1002/ps.4428
       
  • Companion planting with white yarrow or with feverfew for squash bug,
           Anasa tristis (Hemiptera: Coreidae) management on summer squash
    • Authors: Brian A. Kahn; Eric J. Rebek, Lynn P. Brandenberger, Keith Reed, Mark E. Payton
      Abstract: BACKGROUND The squash bug, Anasa tristis (De Geer) is a major insect pest of cucurbits. Control of squash bugs with insecticidal chemicals is difficult to achieve. We investigated the potential of companion planting with white yarrow (Achillea millefolium L.) or feverfew [Tanacetum parthenium (L.) Sch. Bip.] for squash bug management in field plantings of summer squash (Cucurbita pepo L.). RESULTS Companion planting with white yarrow had few effects. Companion planting with feverfew tended to reduce squash bug populations, but results often were not statistically significant (P ≥ 0.05). Early‐season ventilated row covers (without herbs) neither reduced squash bug populations nor increased squash yields. Herbs reduced marketable squash yields compared with the control only once out of seven experiments. CONCLUSION The tested companion planting strategies inconsistently affected squash bug populations on summer squash. Therefore, these strategies are not recommended to commercial producers.
      PubDate: 2016-09-08T04:00:19.557072-05:
      DOI: 10.1002/ps.4427
       
  • How well will stacked transgenic pest/herbicide resistances delay pests
           from evolving resistance?
    • Authors: Jonathan Gressel; Aaron J. Gassmann, Micheal D. K. Owen
      Abstract: Resistance has evolved to single transgenic traits engineered into crops for arthropod and herbicide resistances, and can be expected to evolve to the more recently introduced pathogen resistances. Combining transgenes against the same target pest is being promoted as the solution to the problem. This solution would have worked if used pre‐emptively, but where resistance has evolved, resistance should easily evolve for the second gene in most cases. We propose and elaborate criteria that could be used to evaluate the value of stacked traits for pest resistance management. Stacked partners must: target the same pest species; be in a tandem construct to preclude segregation; be synchronously expressed in same tissues; have similar tissue persistence; target pest species that are still susceptible to at least two stacked partners. Additionally, transgene products must not be degraded in the same manner, and there should be a lack of cross‐resistance to stacked transgenes or to their products. With stacked herbicide resistance transgenes, both herbicides must be used and have the same persistence. If these criteria are followed, and integrated with other pest management practices, resistance may be considerably delayed.
      PubDate: 2016-09-06T09:00:40.298584-05:
      DOI: 10.1002/ps.4425
       
  • Value of Neonicotinoid Seed Treatments to US Soybean Farmers
    • Authors: Terry Hurley; Paul Mitchell
      Abstract: BACKGROUND The benefits of neonicotinoid seed treatment to soybean farmers have received increased scrutiny. Rather than use data from small‐plot experiments, this research uses survey data from 500 US farmers to estimate the benefit of neonicotinoid seed treatments to them. As seed treatment users, farmers are familiar with their benefits in the field and have economic incentives to only use them if they provide value. RESULTS Of the surveyed farmers, 51% used insecticide seed treatments, averaging 87% of their soybean area. Farmers indicated that human and environmental safety is an important consideration affecting their pest management decisions and reported aphids as the most managed and important soybean pest. Asking farmers who used seed treatments to state how much value they provided gives an estimate of US$28.04 ha−1 treated in 2013, net of seed treatment costs. Farmer reported average yields provided an estimated average yield gain of 128.0 kg ha−1 treated in 2013, or about US$42.20 ha−1 treated, net of seed treatment costs. CONCLUSION These estimates using different data and methods are consistent and suggest the value of insecticide seed treatments to the US soybean farmers that used them in 2013 was around US$28 to US$42 ha−1 treated, net of seed treatment costs.
      PubDate: 2016-08-30T23:20:23.534231-05:
      DOI: 10.1002/ps.4424
       
  • Identifying obstacles and ranking common biological control research
           priorities for Europe to manage most economically important pests in
           arable, vegetable and perennial crops
    • Abstract: BACKGROUND EU agriculture is currently in transition from conventional crop protection to integrated pest management (IPM). Because biocontrol is a key component of IPM, many European countries recently have intensified their national efforts on biocontrol research and innovation (R&I) although such initiatives are often fragmented. The operational outputs of national efforts would benefit from closer collaboration among stakeholders via transnationally coordinated approaches since most economically important pests are similar across Europe. RESULTS This paper proposes a common European framework on biocontrol R&I. It identifies generic R&I bottlenecks and needs as well as priorities for three crop types (arable, vegetable and perennial crops). CONCLUSIONS The existing gap between the market offers of biocontrol solutions and the demand of growers, the lengthy and expensive registration process for biocontrol solutions and their varying effectiveness due to variable climatic conditions and site‐specific factors across Europe are key obstacles hindering the development and adoption of biocontrol solutions in Europe. Considering arable, vegetable and perennial crops, a dozen of common target pests are identified for each type of crop and ranked by order of importance at European level. Such a ranked list indicates numerous topics on which future joint transnational efforts would be justified.
      PubDate: 2016-08-28T23:35:36.243768-05:
      DOI: 10.1002/ps.4423
       
  • Evaluation of antifungal activities and structure‐activity relationships
           of Coumarin Derivatives
    • Abstract: BACKGROUND Osthol is a natural coumarin and lead compound that has been developed into commercial fungicides in China. Natural coumarins comprise five major subtypes—simple coumarins, linear furanocoumarins, angular furanocoumarins, linear pyranocoumarins, and angular pyranocoumarins. Studies pertaining to the antifungal activities of linear pyranocoumarins are few, and no reports exist for the antifungal activities of angular pyranocoumarins. In order to discover more antifungal natural coumarins, we synthesized a series of simple natural coumarins and isolated several plant‐based furanocoumarins and pyranocoumarins using previously described methods. The compounds were biologically evaluated against some plant fungal pathogens. RESULTS Several of the 35 coumarins evaluated here exhibited strong activities against specific fungal species, including Compound 25 (Pd‐D‐V, a linear pyranocoumarin), Compound 26 (libanorin, an angular furanocoumarin), and Compound 34 (disenecioyl khellactone, an angular pyranocoumarin). Compound 25 exhibited a high activity against Sclerotinia sclerotiorum (EC50=13.2 µg·mL−1); Compound 34 displayed a strong antifungal activity against Botrytis cinerea (EC50=11.0 µg·mL−1). CONCLUSION This study demonstrates that several natural coumarins (one linear pyranocoumarin and one angular pyranocoumarin in particular) exhibit strong antifungal activities. These results compel further studies, where these coumarins can be examined as potential lead compounds for developing novel antifungal agents.
      PubDate: 2016-08-28T23:35:25.622971-05:
      DOI: 10.1002/ps.4422
       
  • Effect of nonwoven fabric covering on residual activity of pendimethalin
           in lettuce and soil
    • Abstract: BACKGROUND Lettuce (Lactuca sativa L.) is a crop very sensitive to herbicide contamination due to its short growing season. Use of long‐residual herbicides and nonwoven fabric coverings could therefore influence pendimethalin concentrations in soil and lettuce. RESULTS Pendimethalin half‐life in soil ranged between 18 and 85 days and was mainly affected by season (i.e., weather), especially by soil moisture. Pendimethalin degradation in soil was slowest under dry conditions. Longer pendimethalin half‐life was observed under the nonwoven fabric treatment, but the effect of varying application rate was not significant. Pendimethalin residue concentrations in lettuce heads were significantly influenced by pendimethalin application rate and by nonwoven fabric cover, especially at lettuce's early growth stages. The highest pendimethalin concentration at final harvest was determined in lettuce grown on uncovered plots treated by pendimethalin at application rate 1,200 g ha−1 (7–38 µg kg−1). Depending on growing season duration and weather conditions, pendimethalin concentrations in lettuce grown under nonwoven fabric ranged from 0 to 21 µg kg−1. CONCLUSION Use of transparent nonwoven fabric cover with lettuce can help reduce application rates of soil herbicides and diminish the risk of herbicide contamination in the harvested vegetables.
      PubDate: 2016-08-25T03:46:10.492193-05:
      DOI: 10.1002/ps.4421
       
  • Antifungal activity of fabricated mesoporous alumina nanoparticles against
           rot root disease of tomato caused by Fusarium oxysporium
    • Authors: Mohamed Shenashen; Aly Derbalah, Amany Hamza, Ahmed Mohamed, Sherif El Safty
      Abstract: BACKGROUND The present work involved the synthesis and characterization of mesoporous alumina sphere (MAS) nanoparticles to evaluate their biological activity against tomato root rot caused by Fusarium oxysporium, as compared with the recommended fungicide, tolclofos‐methyl, under laboratory and greenhouse conditions. The effects of MAS on the growth of tomato plants were also evaluated and compared with those of tolclofos‐methyl. RESULTS The physical characteristics and structural features of MAS, such as the large surface‐area‐to‐volume ratio, active surface sites, and open channel pores, caused the high antifungal efficacy against Fusarium oxysporium. MAS presented an antifungal potential similar to that of tolclofos‐methyl and much greater than the control under both laboratory and greenhouse conditions. The highest growth parameters were recorded in tomato plants treated with MAS, followed by those treated with tolclofos‐methyl. CONCLUSIONS Our study demonstrated the possible use of cylindrically cubic MAS as effective alternative to control Fusarium rot root in tomato.
      PubDate: 2016-08-25T03:46:03.902005-05:
      DOI: 10.1002/ps.4420
       
  • Bioassimilable Sulfur Provides Effective Control of Oidium neolycopersici
           in Tomato Enhancing Plant Immune System
    • Abstract: BACKGROUND Development of alternatives to the use of chemical pesticides to control pests are focused on the induction of natural plant defenses. The study of new compounds based on liquid bioassimilable sulfur and its effect as an inductor of the immune system of plants would provide an alternative option to farmers to enhance plant resistance against pathogen attacks such as powdery mildew. In order to elucidate the efficacy of this compound in tomato against powdery mildew, we tested several treatments: curative foliar, preventive foliar, preventive in soil drench and combining preventive in soil drench and curative foliar. RESULTS In all cases, treated plants showed lower infection development, better physiological parameters and a higher level of chlorophyll. We also observed better performance in parameters involved in plant resistance such as antioxidant response, callose deposition and hormonal levels. CONCLUSION The results indicate that preventive and curative treatments can be highly effective for the prevention and control of powdery mildew in tomato plants. Foliar treatments are able to stop the pathogen development when they are applied as curative. Soil drench treatments induce immune response mechanisms of plants, increasing significantly callose deposition and promoting plant development.
      PubDate: 2016-08-25T03:46:02.444867-05:
      DOI: 10.1002/ps.4419
       
  • An integrated pest control strategy against the Asian tiger mosquito in
           northern Italy: a case study
    • Abstract: BACKGROUND In Europe, Aedes albopictus is an invasive mosquito species known to be a major nuisance as well as a vector of a range of arboviruses. A number of studies have indicated that community participation programs are an effective pest control tool to reduce mosquito populations. However, few studies have evaluated the effectiveness of a community‐based approach in Europe. In this study, we examined two Ae. albopictus control strategies that implemented a community‐based approach in northern Italy: one was a partial intervention that included a public education campaign and the larviciding of public spaces, and the other was a full intervention that additionally included a door‐to‐door campaign. This latter consisted of going door to door to actively educate residents about control measures and deliver larvicide tablets for treating catch basins at home. A site where no intervention measures were carried out was used as a control. RESULTS In the site where a full intervention was carried out, Ae. albopictus egg density was 1.6 times less than at the site that received partial intervention, and 1.9 times less than at the non‐intervention site. No significant reduction in egg density was achieved in the partial intervention site. CONCLUSIONS In our study, Ae. albopictus populations were most effectively reduced by larviciding both public and private catch basins. Door‐to‐door education was effective in convincing residents to apply control measures on their property; however, this method was labor intensive and costly. It may be possible to reduce personnel costs by involving volunteers or using a ‘hot spot’ approach.
      PubDate: 2016-08-19T04:55:41.556767-05:
      DOI: 10.1002/ps.4417
       
  • Distributions of imidacloprid, imidacloprid‐olefin and
           imidacloprid‐urea in green plant tissues and roots of rapeseed (Brassica
           napus) from artificially contaminated potting soil
    • Authors: Marcela Seifrtova; Tatana Halesova, Klara Sulcova, Katerina Riddellova, Tomas Erban
      Abstract: Background Imidacloprid‐urea is the primary imidacloprid soil metabolite, whereas imidacloprid‐olefin is the main plant‐relevant metabolite and is more toxic to insects than imidacloprid. We artificially contaminated potting soil and used quantitative UHPLC‐QqQ‐MS/MS to determine the imidacloprid, imidacloprid‐olefin and imidacloprid‐urea distributions in rapeseed green plant tissues and roots after 4 weeks of exposure. Results In soil, the imidacloprid/imidacloprid‐urea molar ratios decreased similarly after the 250 and 2500 µg/kg imidacloprid treatments. The imidacloprid/imidacloprid‐urea molar ratios in the root and soil were similar, whereas in the green plant tissue, imidacloprid‐urea increased more than two‐fold compared to the root. Although imidacloprid‐olefin was prevalent in the green plant tissues with imidacloprid/imidacloprid‐olefin molar ratios of 2.24 and 1.47 for the 250 and 2500 µg/kg treatments, respectively, it was not detected in the root. However, imidacloprid‐olefin was detected in the soil after the 2500 µg/kg imidacloprid treatment. Conclusions Significant proportions of imidacloprid‐olefin and imidacloprid‐urea in green plant tissues were demonstrated. The greater imidacloprid supply increased the molar ratio of imidacloprid‐olefin/imidacloprid in the green plant tissues. The absence of imidacloprid‐olefin in the root excluded its re‐transport from leaves. The similar imidacloprid/imidacloprid‐urea ratios in the soil and root indicated that the root serves primarily for transporting these substances.
      PubDate: 2016-08-19T04:51:39.911353-05:
      DOI: 10.1002/ps.4418
       
  • Pathogenic nature of Syncephalastrum in Atta sexdens rubropilosa fungus
           gardens
    • Authors: Mariana O. Barcoto; Felipe Pedrosa, Odair C. Bueno, Andre Rodrigues
      Abstract: BACKGROUND Leaf‐cutter ants are considered a major herbivore and agricultural pest in the Neotropics. They are often controlled by environmentally persistent insecticides. Biological control using pathogenic fungi is regarded as an alternative for the management of these insects. Here, we assess whether the filamentous fungus Syncephalastrum sp. is a pathogenic microorganism, responsible for a characteristic disease in fungus gardens. We also characterize the damage caused by this fungus by evaluating physiological and behavioral responses of Atta sexdens rubropilosa sub‐colonies infected with Syncephalastrum sp. RESULTS Syncephalastrum sp. fulfills Koch's postulates, characterizing it as a pathogenic microorganism. Ant workers recognize the infection and remove contaminated fragments from the fungus garden. Syncephalastrum sp. infection causes an interruption of foraging activity, an increase in ant mortality, sub‐colony deterioration and increase in the amount of waste generated, all resulting in sub‐colony death. Syncephalastrum sp. also inhibits the ant fungal cultivar in vitro. The pathogenic effect of Syncephalastrum sp. does not depend on host morbidity or stress (e.g., worker mortality caused by an entomopathogenic fungus). CONCLUSION Syncephalastrum sp. treatment resulted in progressive damage in sub‐colonies. The interactions among Syncephalastrum sp., fungus garden and ants offer new opportunities in integrated pest management of leaf‐cutting ants.
      PubDate: 2016-08-19T04:40:39.329224-05:
      DOI: 10.1002/ps.4416
       
  • Termiticidal lectins from Myracrodruon urundeuva (Anacardiaceae) cause
           midgut damages when ingested by Nasutitermes corniger (Isoptera;
           Termitidae) workers
    • Abstract: BACKGROUND Myracrodruon urundeuva is a hardwood tree whose bark, heartwood, and leaf contain lectins (MuBL, MuHL and MuLL, respectively) with termiticidal activity against Nasutitermes corniger. In this work, the effects of these lectins on the midgut of N. corniger workers were evaluated. RESULTS The insects were supplied with an artificial diet containing the lectins at their respective LC50 (previously determined). Forty‐eight hours after the treatment, the midguts were dissected and fixed for histopathology analyses. Toluidine blue‐stained midguts from lectin‐treated workers showed disorganization, with presence of debris in the lumen and absence of the brush border. Fluorescence microscopy revealed that the numbers of digestive and proliferating cells were lower in lectin‐treated individuals than in the control, and caspase‐3 staining confirmed occurrence of cell apoptosis. Enteroendocrine cells were not seen in the treated individuals. The midguts from treated insects showed greater staining for peroxidase than the control, suggesting that the lectins caused oxidative stress. Staining with wheat germ agglutinin conjugated to FITC revealed that the lectins interfered with the integrity of the peritrophic matrix. CONCLUSION This study showed that termiticidal lectins from M. urundeuva cause severe injuries, oxidative stress and cell death in the midgut of N. corniger workers.
      PubDate: 2016-08-16T21:15:24.999825-05:
      DOI: 10.1002/ps.4415
       
  • Pyrethroid resistance is associated with a kdr‐type mutation (L1014F) in
           the potato tuber moth Tecia solanivora
    • Abstract: BACKGROUND The Guatemalan potato tuber moth, Tecia solanivora, has been the most important pest species in Hispanico‐American potato fields since its first record on potatoes in 1956 in Guatemala. This insect pest has been spreading to other parts of the world, including the Canary Islands in Europe. The tuber moth control relies heavily on the use of insecticides, including pyrethroids. Here, we assessed the likelihood of control failures and performed concentration‐response bioassays in five Colombian strains of T. solanivora to evaluate their susceptibilities to the pyrethroid permethrin. RESULTS Evidence of control failures was observed in four strains tested, which exhibited moderate resistance levels (i.e., ranging from 5.4‐ to 24.4‐fold). However, no spatial dependence was observed between the permethrin LC50 values and the geographic distances among the tuber moth strains. In order to evaluate whether permethrin resistance was mediated by potential mutations in the para‐type sodium channels of T. solanivora, the IIS4–IIS6 region of the para gene was PCR‐amplified and sequenced from the five strains tested. As demonstrated across a range of different arthropod species that exhibited knockdown resistance (kdr), we observed a single point substitution (L1014F) at high frequencies in the para gene of all four resistant strains. CONCLUSIONS This is the first identification of a target‐site alteration based resistance in the Guatemalan potato tuber moth T. solanivora, which is widespread and exhibits high frequencies among geographically distant strains indicating that pyrethroids are probably becoming ineffective for the control of this pest species.
      PubDate: 2016-08-08T13:18:13.091755-05:
      DOI: 10.1002/ps.4414
       
  • Impact of Glyphosate Resistant Corn, Glyphosate Applications, and Tillage
           on Soil Nutrient Ratios, Exoenzyme Activities and Nutrient Acquisition
           Ratios
    • Authors: Michael B. Jenkins; Martin A. Locke, Krishna N. Reddy, Daniel S. McChesney, R.Wade Steinriede
      Abstract: BACKGROUND We report results of the last two years of a 7‐year field experiment designed to test the null hypothesis: applications of glyphosate on glyphosate resistant (GR) and non‐resistant (nonGR) corn (Zea mays L.) under conventional tillage and no‐till would have no effect on soil exoenzymes and microbial activity. RESULTS Bulk soil (BS) and rhizosphere soil (RS) macronutrient ratios were not affected by either GR or nonGR corn, or glyphosate applications. Differences observed between exoenzyme activities were associated with tillage rather than glyphosate applications. In 2013 nutrient acquisition ratios for bulk and rhizosphere soils indicated P limitations, but sufficient assimilable N. In 2014 P limitations were observed for bulk and rhizosphere soils, in contrast to balanced C and N acquisition ratios in rhizosphere soils. Stoichiometric relationships indicated few differences between glyphosate and non‐glyphosate treatments. Negative correlations between C:P and N:P nutrient ratios and nutrient acquisition ratios underscored the inverse relation between soil nutrient status and microbial community exoenzyme activities. CONCLUSIONS Inconsistent relationships between microbial community metabolic activity and exoenzyme activity indicated an ephemeral effect of glyphosate on BS exoenzyme activity. Except for ephemeral effects, glyphosate applications appeared not to affect the function of the BS and RS exoenzymes under conventional tillage or no‐till.
      PubDate: 2016-08-05T02:45:23.642837-05:
      DOI: 10.1002/ps.4413
       
  • Amitraz and its metabolite differentially activate α‐ and
           β‐adrenergic‐like octopamine receptors
    • Authors: Tomo Kita; Takeshi Hayashi, Tomohiro Ohtani, Haruka Takao, Hiroshi Takasu, Genyan Liu, Hiroto Ohta, Fumiyo Ozoe, Yoshihisa Ozoe
      Abstract: BACKGROUND Amitraz is a formamidine acaricide and insecticide used to control ticks, mites and fleas. N2‐(2,4‐Dimethylphenyl)‐N1‐methyformamidine (DPMF), a metabolite of amitraz, is thought to be an active agent that exerts acaricidal and insecticidal effects by acting as an agonist on octopamine receptors. The emergence of cattle ticks resistant to amitraz is a serious problem that requires urgent attention. The objective of this research was to determine which type of octopamine receptor is the primary target of amitraz and thereby understand the molecular mechanisms of action and resistance to amitraz. RESULTS Amitraz and DPMF potently activated Bombyx mori α‐ and β‐adrenergic‐like octopamine receptors (α‐ and β‐AL OARs) that were stably expressed in HEK‐293 cells. Notably, DPMF elevated intracellular cAMP levels with an EC50 of 79.6 pM in β‐AL OARs, the transcripts of which were prevalently and widely localized in B. mori body parts. Furthermore, DPMF elevated the intracellular Ca2+ levels, with an EC50 of 1.17 nM in α‐AL OARs. CONCLUSION Although both amitraz and DPMF acted as OAR agonists, the metabolite DPMF was more potent than amitraz and differentially activated α‐ and β‐AL OARs. The present findings provide a basis for studies to examine the mechanism of amitraz resistance and to develop novel acaricides and insecticides.
      PubDate: 2016-08-03T02:50:30.805151-05:
      DOI: 10.1002/ps.4412
       
  • Can Herbicide Safeners Allow Selective Control of Weedy Rice Infesting
           Rice Crops?
    • Authors: Roberto Busi; Nghia K Nguyen, Bhagirath S Chauhan, Francesco Vidotto, Maurizio Tabacchi, Stephen B Powles
      Abstract: BACKGROUND Rice is a major field crop of paramount importance for global food security. However, the increased adoption of more profitable and resource‐efficient direct‐seeded rice systems (DSR) has contributed to greater weed infestations including weedy rice that has become a severe problem in several Asian regions. In this study we have developed a conceptually novel method to protect rice plants at high doses of clomazone and triallate. RESULTS The insecticide phorate applied to rice seeds provided substantial level of protection against the herbicides clomazone or triallate. Fifteen kg phorate ha−1 significantly increased the LD50 values >2‐fold greater than rice plants treated only with clomazone. Twenty kg phorate ha−1 in combination with 2,000 g triallate ha−1 safened rice plants (80% survival) with LD50 >3.4‐fold greater than in phorate‐untreated rice. Weed control efficacy was not lowered by the presence of phorate‐treated rice seeds. CONCLUSION Weedy rice is one of the most damaging global weeds and a major threat of DSR systems. In this study we have developed a proof‐of‐concept method to allow selective weedy rice control in rice crops. We call for herbicide discovery programs and research to identify candidate safener and herbicide combinations to achieve selective herbicide control of weedy rice and alleviate weed infestations in global rice crops.
      PubDate: 2016-08-03T02:35:24.745099-05:
      DOI: 10.1002/ps.4411
       
  • Rapid Killing of Bed Bugs (Cimex lectularius L.) on Surfaces using Heat:
           Application to Luggage
    • Authors: Catherine Loudon
      Abstract: BACKGROUND The resistance of bed bugs (Cimex lectularius L.) to chemical insecticides has motivated development of non‐chemical control methods such as heat treatment. However, because bed bugs tend to hide in cracks or crevices, their behavior incidentally generates a thermally‐insulated microenvironment for themselves. Bed bugs located on the outer surface of luggage are less insulated and potentially more vulnerable to brief heat treatment. RESULTS Soft‐sided suitcases with adult male bed bugs on the outside were exposed to an air temperature of 70‐75 °C. It took 6 minutes to kill all of the bed bugs, even those that had concealed themselves under zipper flaps or decorative piping. During heating, only one bed bug (out of 250 total) moved into the luggage (through a closed zipper). Over long periods of time (24 hours) at room temperature, adult male bed bugs on the exterior of luggage only infrequently moved inside; only 3% (5/170) had moved inside during 24 hours. CONCLUSIONS Brief exterior heat treatment of luggage is a promising way to decrease the spread of bed bugs being transported on the outer surface of luggage. This treatment will not kill bed bugs inside the luggage, but could be a component of integrated management for this pest.
      PubDate: 2016-08-01T00:01:07.142822-05:
      DOI: 10.1002/ps.4409
       
  • Oral delivery of dsRNA lipoplexes to German cockroach protects dsRNA from
           degradation and induces RNAi response
    • Abstract: BACKGROUND In the past years, the concept of RNAi application for insect pest control has been proposed, considering the disruption of vital genes. However, the efficiency of RNAi is variable between different insect groups, especially by oral delivery of dsRNA. The purpose of this study is to assess the possibilities of RNAi as a tool for pest control using oral delivery of the dsRNAs encapsulated by liposome in the German cockroach Blattella germanica, which is highly sensitive to RNAi by injection of dsRNAs. RESULTS Injecting dsRNA into the abdomen of B. germanica caused dramatic depletion of essential α‐tubulin gene and mortality. In contrast, oral delivery of the naked dsRNA resulted in lower RNAi efficiency accounted for rapid degradation of the dsRNA in the midgut of B. germanica. Notably, we have further demonstrated that continuous ingestion of dsRNA lipoplexes, which dsRNA was encapsulated with a cationic liposome carrier, was sufficient to slow down the degradation of dsRNA in the midgut and to increase the mortality of the German cockroach by significantly inhibiting α‐tubulin expression in the midgut. CONCLUSION We provide the empirical evidence that the formulation of dsRNA lipoplexes could be a plausible approach for insect pest control based on RNAi.
      PubDate: 2016-07-29T06:20:33.573851-05:
      DOI: 10.1002/ps.4407
       
  • Estimating the effect of plant‐provided food supplements on pest
           
    • Abstract: BACKGROUND Plant‐provided food supplements can influence biological pest control by omnivorous predators in two counteracting ways: (i) enhance predator populations, but (ii) reduce pest consumption by individual predators. Yet the majority of studies address only one of these aspects. Here, we first tested the influence of canola (Brassica napus L.) pollen supplements on the life history of two ladybeetle species: Hoppodamia variegata (Goeze) and Coccinella septempunctata (L.). We then developed a theoretical model to simulate total pest consumption in the presence and absence of pollen supplements. RESULTS Supplementing a prey diet with canola pollen increased H. variegata larvae survival from 50% to 82%, and C. septempunctata female oviposition by 1.6 fold. Model simulations revealed a greater benefit of pollen supplements when relying on C. septempunctata for pest suppression than on H. variegata. CONCLUSION For these two predators, the tested pollen serves as an essential supplement to a diet of prey. However, the benefit of a mixed prey‐pollen diet was not always sufficient to overcome individual decrease in pest consumption. Taken together, our study highlights the importance of addressing both positive and negative roles of plant‐provided food supplements in considering the outcome for biological control efforts that rely on omnivorous predators.
      PubDate: 2016-07-29T06:20:23.772466-05:
      DOI: 10.1002/ps.4410
       
  • Determining the geographical origin of Asian longhorn beetle (Anoplophora
           glabripennis) specimens using stable isotope and trace element analyses
    • Authors: Katharina Heinrich; Larissa Collins
      Abstract: BACKGROUND An outbreak of EU quarantine listed pest Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambicidae), Asian Longhorn Beetle, in Kent (UK) resulted in environmentally and financially costly eradication action being taken. In this study the potential of using multi‐element stable isotope or trace element analyses to determine the geographical origin of individual specimens has been investigated. RESULTS The isotope ratios of A. glabripennis individuals for hydrogen varied within and across 5 locations. Carbonisotope ratios fell within the expected values for C3 plants (trees using the photosynthetic pathway common for moderate climates). Nitrogen isotope ratios indicated separation of UK laboratory from American (New York, Ohio, Massachusetts) beetles; whilst sulfur isotope ratios distinguished beetles from New York against the other 4 locations. Three trace elements (TEs) separated UK laboratory‐reared beetles from American beetles (Ohio and New York) with ~ 68% confidence. CONCLUSIONS Stable isotope and TE analyses show potential to differentiate between newly arrived A. glabripennis individuals and those from previously undetected in‐country populations, which would be of immediate practical benefit in making appropriate strategic decisions on surveillance and eradication. Analyses of additional samples (i) from the same populations, (ii) different locations and (iii) variety of host trees will enhance the overall picture.
      PubDate: 2016-07-29T06:15:45.448612-05:
      DOI: 10.1002/ps.4408
       
  • Intermediate derivatization method in the discovery of new acaricide
           candidate: synthesis of N‐substituted piperazines derivatives and their
           activity against phytophagous mites
    • Authors: Yong Xie; Ying Xu, Changling Liu, Aiying Guan, Lanfeng Ban, Fei Ding, Wei Peng
      Abstract: BACKGROUND To discover and exploit novel acaricidal compounds, a series of novel N‐substituted piperazines derivatives were designed and synthesized using a tert‐butyl piperazine‐1‐carboxylate as starting material by intermediate derivatization methods and their acaricidal activities were evaluated. RESULTS The acaricidal activity showed compounds 11 and 12 exhibited significant acaricidal activity against adults of Tetranychus cinnabarinus in greenhouse tests. Compound 12 in particular was found to be the best potential candidate acaricide and proved more active than that of the commercial positive controls spirodiclofen and pyridaben, with an LC50 of 0.8977 mg L−1. The results of acaricidal activities against larvae and eggs of Tetranychus cinnabarinus indicated that compound 12 possessed equivalent larvicidal activity to spirodiclofen and higher larvicidal activity than pyridaben. Meanwhile, compound 12 showed less ovicidal activity than pyridaben, but higher activity than spirodiclofen. Furthermore, the results of the field trial demonstrated that compound 12 could effectively control Panonychus citri and Panonychus ulmi with long‐lasting persistence and rapid‐acting property. CONCLUSIONS The present work indicates that compound 12 could be a novel acaricide candidate for spider mites control.
      PubDate: 2016-07-23T03:15:32.568748-05:
      DOI: 10.1002/ps.4369
       
  • Synthesis and Insecticidal Activity of Novel Pyrimidine Derivatives
           Containing Urea pharmacophore against Aedes aegypti
    • Abstract: BACKGROUND Aedes aegypti is a major mosquito vector for the transmission of serious diseases, especially dengue and yellow fever. More than one billion people in developing countries are at risk. The widespread and continual use of pesticides can lead to resistant mosquitoes. In order to maintain mosquito control gains, it is critical to develop and evaluate novel bioactive molecules that differ in mode of action from currently used products. RESULTS A series of novel pyrimidine derivatives were designed and synthesized. Their structures were elucidated by 1H NMR and HRMS. Biological activities of these compounds were tested against Aedes aegypti. Many of them exhibited insecticidal activity against adult and larval mosquitoes. Compound 4d displayed relatively good activity to reach 70% mortality at 2 µg/mL. Furthermore, DFT (Density functional theory) calculations were established to study the structure‐activity relationship of these novel compounds. CONCLUSION A practical synthetic route for pyrimidine derivatives is presented. This study suggests that these pyrimidine derivatives exhibited some activity against the yellow fever mosquito, and with further structure modification, could be novel lead compounds for the development of insecticides against mosquitoes.
      PubDate: 2016-07-23T03:15:26.888181-05:
      DOI: 10.1002/ps.4370
       
  • Efficacy of tebuconazole embedded in biodegradable
           poly‐3‐hydroxybutyrate to inhibit the development of Fusarium
           moniliforme in soil microecosystems
    • Abstract: Background An important line of research is the development of a new generation of formulations with targeted and controlled release of the pesticide, using matrices made from biodegradable materials. In this study, slow‐release formulations of the fungicide tebuconazole (TEB) have been prepared by embedding it into the matrix of poly‐3‐hydroxybutyrate (P3HB) in the form of films, microgranules, and pellets. Results The average rates of P3HB degradation rates were determined by the geometry of the formulation, reaching for 63 days 0.095‐0.116; 0.081‐0.083; 0.030‐0.055 mg d−1 for films, microgranules, and pellets, respectively. The fungicidal activity of P3HB/TEB against the plant pathogen Fusarium moniliforme was compared with that of the commercial formulation Raxil Ultra. A pronounced fungicidal effect of the experimental P3HB/TEB formulations was observed in 2–4 weeks after application, and it was retained for 8 weeks, without affecting significantly the development of soil aboriginal microflora. Conclusions TEB release can be regulated by the process employed to fabricate the formulation and the fungicide loading and that TEB accumulates in the soil gradually, as the polymer is degraded. The experimental forms of TEB embedded in the slowly degraded P3HB can be used as a basis for developing slow‐release fungicide formulations.
      PubDate: 2016-07-22T09:20:27.285264-05:
      DOI: 10.1002/ps.4367
       
  • Forward selection for multiple resistance across the non‐selective
           
    • Abstract: BACKGROUND In the Mediterranean area, Lolium species have evolved resistance to glyphosate after decades of continue use without other alternative chemicals in perennial crops (olive, citrus and vineyard). In recent years, oxyfluorfen alone or mixed with glyphosate and glufosinate have been introduced as chemical options to control dicot and grass weeds. RESULTS Dose response studies confirmed that three glyphosate resistant Lolium weed species (L. rigidum, L. perenne, L. multiflorum) collected from perennial crops in the Iberian Peninsula have also evolved resistance to glufosinate and oxyfluorfen herbicides, despite their recent introduction. Based on LD50 resistance parameter, resistance factor was similar among Lolium species and ranged from 14‐21‐fold and 10‐12‐fold for oxyfluorfen and glufosinate, respectively. Similarly, about 14‐fold resistance to both oxyfluorfen and glufosinate was estimated in average for the three Lolium species when growth reduction (GR50) was assessed. This study identified oxyfluorfen resistance in a grass species for the first time. CONCLUSION A major threat to sustainability of perennial crops in the Iberian Peninsula is evident as multiple resistance to non‐selective glyphosate, glufosinate and oxyfluorfen herbicides has evolved in L. rigidum, L. perenne and L. multiflorum weeds.
      PubDate: 2016-07-22T09:20:24.457363-05:
      DOI: 10.1002/ps.4368
       
  • Susceptibility of Selected Boreal Fruits and Berries to the Invasive Pest
           Drosophila suzukii (Diptera: Drosophilidae)
    • Authors: Catherine M Little; Thomas W Chapman, Debra L Moreau, N Kirk Hillier
      Abstract: BACKGROUND Drosophila suzukii Matsumara has recently emerged as a major invasive pest species in soft‐skinned fruits in berries throughout N. America and Europe. Its distribution has spread so rapidly that little is known of the extent of fruit susceptibility, particularly in boreal regions. Populations of D. suzukii increase dramatically in late summer in boreal regions, concurrent with fruiting seasons for commercially and culturally significant fruits and berries. We tested fruit preference and susceptibility of lingonberry, blueberry, chokecherry, sea buckthorn, and raspberry fruits to D. suzukii. RESULTS Female D. suzukii attempted to oviposit on all fruit types tested. Fruits with lower brix and lower pH levels were preferred in choice tests. Undamaged lingonberries were relatively safe from infestation; however, bruised or frost‐damaged fruits were easily penetrated. Sea buckthorn and raspberry fruits were highly preferred. CONCLUSIONS Although blueberry growers have experienced severe economic crop losses due to D. suzukii, we have found that blueberries were the least preferred of fruits tested. This suggests that D. suzukii are largely opportunistic and highlights the importance of fruit phenology in fruit susceptibility.
      PubDate: 2016-07-22T09:15:59.719798-05:
      DOI: 10.1002/ps.4366
       
  • Systemic RNAi in the small hive beetle (Aethina tumida Murray, Coleoptera:
           Nitidulidae), a serious pest of the European honey bee (Apis mellifera)
    • Authors: Michelle E. Powell; Hannah M. Bradish, John A. Gatehouse, Elaine C. Fitches
      Abstract: BACKGROUND Aethina tumida is a serious pest of the European honey bee (Apis mellifera) in North America and Australia. Here we investigate whether Laccase 2, phenoloxidase gene essential for cuticle sclerotization and pigmentation in many insects, and vacuolar‐ATPase V‐type subunit A, vital for the generation of proton gradients used to drive a range of transport processes, could be potential targets for RNAi‐mediated control of A. tumida. RESULTS Injection of V‐ATPase subunit A (5 ng) and Laccase 2 (12.5 ng) dsRNAs resulted in 100 % larval mortality, qPCR confirmed significant decreases and enhanced suppression of transcript levels over time. Oral delivery of V‐ATPase subunit A dsRNA in solutions resulted in 50 % mortality, however gene suppression could not be verified. We suggest that the inconsistent RNAi effect was a consequence of dsRNA degradation within the gut due to the presence of extracellular nucleases. Target specificity was confirmed by a lack of effect on survival or gene expression in honey bees injected with A. tumida dsRNAs. CONCLUSIONS This is the first study to show evidence for systemic RNAi in A. tumida in response to injected dsRNA but further research is required to develop methods to induce RNAi effects via ingestion.
      PubDate: 2016-07-22T09:10:32.046249-05:
      DOI: 10.1002/ps.4365
       
  • Recurrent selection with reduced 2,4‐D amine doses results in the rapid
           evolution of 2,4‐D herbicide resistance in wild radish (Raphanus
           raphanistrum L.)
    • Authors: Michael B. Ashworth; Michael J. Walsh, Ken C. Flower, Stephen B. Powles
      Abstract: BACKGROUND When used at effective doses, weed resistance to auxinic herbicides has been slow to evolve when compared to other modes of action. Here we report the evolutionary response of a herbicide‐susceptible population of wild radish (Raphanus raphanistrum L.) and confirm that sub‐lethal doses of 2,4‐D amine can lead to the rapid evolution of 2,4‐D resistance and cross resistance to acetolactate synthase (ALS) inhibiting herbicides. RESULTS Following four generations of 2,4‐D selection, the progeny of a herbicide‐susceptible wild radish population evolved 2,4‐D resistance, increasing the LD50 from 16 g ha−1 to 138 g ha−1. Along with 2,4‐D resistance, cross resistance to the ALS‐inhibiting herbicides metosulam (4.0‐fold), and chlorsulfuron (4.5‐fold) was evident. Pre‐treatment of the 2,4‐D‐selected population with the cytochrome P450 inhibitor, malathion, restored chlorsulfuron to full efficacy, indicating that cross resistance to chlorsulfuron was likely due to P450 catalysed enhanced rates of herbicide metabolism. CONCLUSION This study is the first to confirm the rapid evolution of auxinic herbicide resistance through the use of low doses of 2,4‐D and serves as a reminder that 2,4‐D must always be used at highly effective doses. With the introduction of transgenic auxinic herbicide resistant crops in the America's there will be a marked increase in auxinic herbicide use and therefore the risk of resistance evolution. Auxinic herbicides should be used only at effective doses and with diversity if resistance is to remain a minimal issue.
      PubDate: 2016-07-21T11:50:26.311405-05:
      DOI: 10.1002/ps.4364
       
  • Costs and benefits of insecticide and foliar nutrient applications to
           HLB‐infected citrus trees
    • Authors: James A. Tansey; Pilar Vanaclocha, Cesar Monzo, Moneen Jones, Philip A. Stansly
      Abstract: BACKGROUND The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae), vectors ‘Candidatus Liberibacter asiaticus’ that causes huanglongbing (HLB). In Florida, HLB incidence is approaching 100% statewide. Yields have decreased and production costs have increased since 2005. Despite this, some growers are maintaining a level of production and attribute this in part to aggressive psyllid control and foliar nutrition sprays. However, the value of these practices is debated. A replicated field study was initiated in 2008 in a commercial block of ‘Valencia’ sweet orange trees to evaluate individual and combined effects of foliar nutrition and ACP control. Results from 2012–2016 are presented. RESULTS Insecticides consistently reduced ACP populations. However, neither insecticide nor nutrition applications significantly influenced HLB incidence nor PCR copy number in mature trees. In reset trees, infection continued to build and reached 100% in all treatments. Greatest yields (kg fruit/ ha) and production (kg s/ ha) were obtained from trees receiving both insecticides and foliar nutrition. CONCLUSIONS All treatments resulted in production and financial gains relative to controls. However, material and application costs associated with the nutrition component offset these gains resulting in lesser benefits than insecticides applied alone.
      PubDate: 2016-07-18T05:53:45.896665-05:
      DOI: 10.1002/ps.4362
       
  • Structure‐based bioisosterism design, synthesis, insecticidal activity
           and structure‐activity relationship (SAR) of anthranilic diamides
           analogs containing 1,2,4‐oxadiazole rings
    • Abstract: BACKGROUND Anthranilic diamides derivatives are among the most important classes of synthetic insecticides. Besides the 1,2,4‐oxadiazole heterocycle, a bioisostere of amide, has been extensively used in pesticide. In order to discover novel molecules with high insecticidal activities, a series of anthranilic diamides analogs containing 1,2,4‐oxadiazole rings were designed and synthesized. RESULTS A series of novel anthranilic diamides derivatives containing 1,2,4‐oxadiazole were obtained, and confirmed by 1H NMR, 13C NMR and HRMS. The structure of 3‐bromo‐N‐(4‐chloro‐2‐methyl‐6‐(3‐((methylsulfonyl)methyl)‐1,2,4‐oxadiazol‐5‐yl)phenyl)‐1‐(3‐chloropyridin‐2‐yl)‐1H‐pyrazole‐5‐carboxamide was further characterized by X‐ray diffraction analysis. In addition, bioassays showed that most of the newly synthesized compounds displayed 100 % mortality against Plutella xylostella at 100 mg L−1. And compound 3IIl showed 90 % larvicidal activities at the concentration of 0.5 mg L−1. The LC50 value of 3IIl was 0.20 mg L−1, which indicated that it may be used as potential leading compound for further structural optimization. Furthermore, a brief comparative molecular field analysis models were established to study the structure‐activity relationship of the title compounds. CONCLUSION Compound 3IIl may be used as potential leading compound for further structural optimization. And the SAR and CoMFA model could provide reliable clues for further structural optimization.
      PubDate: 2016-07-18T05:53:44.735627-05:
      DOI: 10.1002/ps.4363
       
  • Homozygous and heterozygous point mutations in succinate dehydrogenase
           subunits b, c, and d of Rhizoctonia cerealis conferring resistance to
           thifluzamide
    • Abstract: BACKGROUND Thifluzamide, a succinate dehydrogenase inhibitor (SDHI) fungicide, is a promising fungicide for controlling wheat sharp eyespot (WSE). WSE is caused by Rhizoctonia cerealis. Information on the resistance mechanism of this pathogen to thifluzamide remains unavailable. RESULTS We used selective re‐culturing and UV mutagenesis to generate thifluzamide resistant mutants. Thifluzamide‐resistant mutants were only generated through UV mutagenesis. Sequence analysis of succinate dehydrogenase (Sdh) genes revealed that two mutants had no mutation in RCSdhB, RCSdhC, and RCSdhD and the other 18 mutants all had at least a one mutation in RCSdhB, RCSdhC, or RCSdhD, either in a homozygous or heterozygous state. The majority of mutants included either RCSdhD‐H116Y or RCSdhC‐H139Y. They showed slight resistance to boscalid, bixafen, and penflufen. Only one mutant possessed RCSdhB‐H246Y and it showed medium resistance to boscalid, penflufen, and a slight resistance to bixafen. All the thifluzamide mutants were sensitive to flutolanil. Compared with their parental isolates, these mutants present no or minor fitness penalties. CONCLUSION Homozygous and heterozygous point mutations in the succinate dehydrogenase subunits b, c, and d of R. cerealis may be involved in thifluzamide resistance.
      PubDate: 2016-07-14T09:06:00.392682-05:
      DOI: 10.1002/ps.4361
       
  • Synthesis and Biological Activity of a New Class of Insecticides: the
           N‐(5‐Aryl‐1,3,4‐thiadiazol‐2‐yl)amides
    • Authors: Joseph D. Eckelbarger; Marshall H. Parker, Maurice C. H. Yap, Ann M. Buysse, Jonathan M. Babcock, Ricky Hunter, Yelena Adelfinskaya, Jack G. Samaritoni, Negar Garizi, Tony K. Trullinger
      Abstract: BACKGROUND Optimization studies on a high throughput screening (HTS) hit led to the discovery of a series of N‐(6‐arylpyridazin‐3‐yl)amides with insecticidal activity. It was hypothesized that the isosteric replacement of the pyridazine ring with a 1,3,4‐thiadiazole ring could lead to more potent biological activity and/or broader sap‐feeding pest spectrum. The resulting N‐(5‐aryl‐1,3,4‐thiadiazol‐2‐yl)amides were explored as a new class of insecticides. RESULTS Several methods for 2‐amino‐1,3,4‐thiadiazole synthesis were used for the preparation of key synthetic intermediates. Subsequent coupling to variously substituted carboxylic acid building blocks furnished the final targets, which were tested for insecticidal activity against susceptible strains of Aphis gossypii (Glover) (cotton aphid), Myzus persicae (Sulzer) (green peach aphid), and Bemisia tabaci (Gennadius) (sweetpotato whitefly). CONCLUSIONS Structure‐activity relationship (SAR) studies on both the amide tail and the aryl A‐ring of novel N‐(5‐aryl‐1,3,4‐thiadiazol‐2‐yl)amides led to a new class of insecticidal molecules active against sap‐feeding insect pests.
      PubDate: 2016-07-14T08:55:38.584957-05:
      DOI: 10.1002/ps.4359
       
  • Pro‐Insecticidal Approach Towards Increasing In Planta Activity
    • Authors: Lawrence C. Creemer; Natalie C. Giampietro, William Lambert, Maurice C. Yap, Gerrit J. deBoer, Yelena Adelfinskaya, Scott Castetter, Frank J. Wessels
      Abstract: BACKGROUND The adrenergic mode of action was investigated for the development of potential new insecticides. Clonidine related analogs were tested against Myzus persicae (Sulzer) and Bemisia tabaci (Gennadius). Clonidine analogs lack translation due to a possible vacuole trapping mechanism. Physical properties modulation via a pro‐drug approach was attempted to overcome this mechanism. RESULTS Clonidine showed insecticidal activity against M. persicae and B. tabaci. A pro‐drug of a known open‐chain analog of clonidine, was developed. While the pro‐drug had decreased pKa and increased lipophillicity and displayed good activity against M. persicae and B. tabaci, the activity did not translate on cotton. Metabolic studies showed the pro‐drug was quickly metabolized to the parent compound, and was further metabolized to a known vacuole‐trapped oxazoline analog. CONCLUSIONS Adrenergic active compounds, such as clonidine analogs, show potential as insecticides; however, a designed pro‐drug approach did not overcome lack of translation in this case. Studies confirmed that the synthesized pro‐drug analog metabolized in planta to a proposed vacuole‐trapped compound. One possible explanation for the failure of this approach is that the rate of metabolism and vacuole trapping is faster than translaminar flow and therefore the released pesticide is not biologically available to the target organism.
      PubDate: 2016-07-14T08:55:27.754405-05:
      DOI: 10.1002/ps.4358
       
  • Effects of trans‐2‐Hexenal on Reproduction, Growth and Behavior and
           Efficacy against Pinewood Nematode, Bursaphelenchus xylophilus
    • Authors: Le Cheng; Shuangyu Xu, Chunmei Xu, Hongbao Lu, Zhengqun Zhang, Daxia Zhang, Wei Mu, Feng Liu
      Abstract: BACKGROUND Bursaphelenchus xylophilus is a serious quarantined pest that causes severe damage and major economic losses to pine forests. Because of the adverse effects of some traditional nematicides on human and the environment, new plant toxicants against these nematodes have intensified. Nematicidal activity of trans‐2‐hexenal, which is a six carbon aldehyde present in many plants, was tested against the nematode. RESULTS trans‐2‐Hexenal showed significant efficacy against B. xylophilus at a dose range of 349.5‐699 g m‐3 by fumigation of pine wood logs. Additionally, it had significant nematicidal activity against different life stages of B. xylophilus in‐vitro test, with second‐stage larvae (L2s) being the most sensitive, which had LC50 value of 9.87 µg mL‐1 at 48 h. Egg hatch was also significantly inhibited. Further studies revealed that trans‐2‐hexenal inhibited the reproductive activity of B. xylophilus, with negative effects on reproduction rate and egg numbers. Moreover, trans‐2‐hexenal reduced the body length of B. xylophilus. Respiratory rate and thrashing behavior of B. xylophilus also decreased following treatment with this compound. CONCLUSION trans‐2‐hexenal had significant nematicidal activity against B. xylophilus, providing a basis for elucidation of the mode of action of trans‐2‐hexenal against plant parasitic nematodes in future studies.
      PubDate: 2016-07-14T08:55:25.229031-05:
      DOI: 10.1002/ps.4360
       
  • Effect of plant resistance and BioAct WG (Purpureocillium lilacinum strain
           251) on Meloidogyne incognita in a tomato–cucumber rotation in a
           greenhouse
    • Abstract: BACKGROUND The effectiveness of combining resistant tomato with BioAct WG (Purpureocillium lilacinum strain 251; Pl251) against Meloidogyne incognita was assessed in a tomato‐cucumber rotation in greenhouse over two years. Additionally, the enzymatic activity of the fungus, the percentage of fungal egg and juvenile parasitism, cardinal temperatures and the effect of water potential on mycelial growth and the soil receptivity to Pl251 were determined in vitro. RESULTS Plant resistance was the only factor that suppressed nematode and crop yield losses. Percentage of egg parasitism in plots treated with BioAct WG was less than 2.6 %. However under in vitro conditions, Pl251 showed protease, lipase, and chitinase activities, and parasitized 94.5 % of eggs, but no juveniles. Cardinal temperatures were 14.2, 24‐26, and 35.4 °C. The maximum Pl251 mycelial growth was at ‐0.25 MPa and 25 °C. Soil temperatures and water potential in the greenhouse were in the range of the fungus. However, soil receptivity was less in greenhouse soil, irrespective of sterilization, than in sterilized sand. CONCLUSIONS Plant resistance was the only factor able to suppress nematode densities, disease severity and yield losses, and to protect the following cucumber crop. Environmental factors involved in soil receptivity could have negatively affected fungus effectiveness.
      PubDate: 2016-07-14T08:55:23.174418-05:
      DOI: 10.1002/ps.4357
       
  • Effects of Residual Novaluron on Reproduction in Alfalfa Leafcutting Bees,
           Megachile rotundata F. (Megachilidae)
    • Abstract: Background The chitin synthesis inhibitor novaluron can suppress pests that affect alfalfa seed production, but can negatively impact reproductive success in the alfalfa pollinator Megachile rotundata. Novaluron is considered a reduced risk insecticide because it disrupts ecdysis and is nonlethal to adults, but some exposed adult insects have fewer eggs and suppressed egg hatch. For this experiment, bees nested in field cages where they were exposed to alfalfa never treated with novaluron, alfalfa that was recently sprayed, or alfalfa that had been sprayed one and two weeks earlier. Results Compared to control, greater proportions of dead eggs and larvae and lower proportions of live prepupae occurred when bees were exposed to recent novaluron sprays as well as one‐ or two‐week old spray residues. Two possible routes of residual pesticide exposure were revealed. Mother bees become contaminated through ingestion or direct contact. Or, pollen‐nectar provisions become contaminated with novaluron 1) on or within leaf pieces that surround provisions or 2) transferred from mother bees’ bodies to provisions. Conclusion We found strong immature mortality effects of novaluron and its residues on M. rotundata. Understanding all possible pesticide exposure routes for pollinating bees enhances decision‐making for maintaining bee populations while protecting crops.
      PubDate: 2016-07-12T09:25:19.625365-05:
      DOI: 10.1002/ps.4356
       
  • Sorption and desorption characteristics of methyl bromide during and after
           fumigation of pine (Pinus radiata D. Don) logs
    • Abstract: BACKGROUND The sorption and desorption characteristics of methyl bromide (MB) were determined during and after fumigation of recently harvested pine (Pinus radiata D. Don) logs. The effects of dose (48 or 120 g m−3), degree of bark cover (0, 50 or 100%) and end‐grain sealing (sealed or unsealed) on sorption and desorption were determined over time. RESULTS Sorption of MB was proportional to the dose applied and dependent on the amount of end‐grain sealed. After 16 h, an average of 70.7 ± 2.5% of the initial concentration remained in the treated space when end‐grains were sealed whereas only 47.3 ± 2.5% remained when unsealed. During aeration, MB was released from logs initially ranging from 2.8 to 8.8 g.h m−3, depending on the treatment. The rate of desorption quickly decreased during aeration. CONCLUSION The surface area of a log is the most important factor influencing MB sorption and desorption rates, with greater surface area resulting in a greater (de)sorption rates. Sorption data can now be combined with insect toxicity data to estimate a minimum effective dose of MB for further evaluation; while desorption data can be combined with fumigant plume modelling to assess worker safety.
      PubDate: 2016-07-12T09:16:04.038919-05:
      DOI: 10.1002/ps.4355
       
  • Insecticidal Activity of Novel Thioureas and Isothioureas
    • Authors: William T. Lambert; Miriam E. Goldsmith, Thomas C. Sparks
      Abstract: BACKGROUND We hypothesized that exploration of chemical space around compounds with reported insecticidal activity could be a viable strategy for discovering novel, insecticidally active areas of chemistry. RESULTS A series of thioureas and isothioureas were prepared as part of a scaffold‐hopping effort around known insecticidal compounds. Many of these compounds showed excellent activity against key sap‐feeding insect pests in insecticidal bioassays. While analogs bearing monocyclic thiophene head groups showed activity against Myzus persicae (green peach aphid), analogs with diarylethane head groups were active against both M. persicae and Bemisia tabaci (sweetpotato whitefly). Despite compelling activity in these laboratory tests, these compounds showed diminished activity when applied to host plants via tracksprayer. CONCLUSIONS The initial hypothesis that structural modification of molecules reported to have insecticidal activity would yield novel compounds which also exhibit insecticidal activity was validated. Despite excellent activity in laboratory bioassays, these new compounds failed to show compelling activity in more demanding tracksprayer tests.
      PubDate: 2016-07-08T08:35:25.173009-05:
      DOI: 10.1002/ps.4353
       
  • Weed seed inactivation in soil mesocosms via biosolarization with mature
           compost and tomato processing waste amendments
    • Abstract: BACKGROUND Biosolarization is a fumigation alternative that combines passive solar heating with amendment‐driven soil microbial activity to temporarily create antagonistic soil conditions, such as elevated temperature and acidity, that can inactivate weed seeds and other pest propagules. The aim of this study was to use a mesocosm‐based field trial to assess soil heating, pH, volatile fatty acid accumulation, and weed seed inactivation during biosolarization. RESULTS Biosolarization for 8 days using 2% mature green waste compost and 2 or 5% tomato processing residues in the soil resulted in accumulation of volatile fatty acids in the soil, particularly acetic acid, and >95% inactivation of Brassica nigra and Solanum nigrum seeds. Inactivation kinetics data showed that near complete weed seed inactivation in soil was achieved within the first 5 days of biosolarization. This was significantly greater than the inactivation achieved in control soils that were solar heated without amendment or were amended but not solar heated. CONCLUSION The composition and concentration of organic matter amendments in soil significantly affected volatile fatty acid accumulation at various soil depths during biosolarization. Combining solar heating with organic matter amendment resulted in accelerated weed seed inactivation compared to either approach alone.
      PubDate: 2016-07-08T08:35:21.04782-05:0
      DOI: 10.1002/ps.4354
       
  • Eradicating grey squirrel Sciurus carolinensis from urban areas: an
           innovative decision making approach based on lessons learnt in Italy
    • Authors: Daniele Paoloni; Valentina La Morgia
      Abstract: BACKGROUND Eradication of Invasive Alien Species supports the recovery of native biodiversity. In Europe, a new Regulation introduces obligations to eradicate the most harmful invasive species. However, eradications of charismatic mammals may encounter strong oppositions. Considering the case study of the Eastern grey squirrel (Sciurus carolinensis Gmelin, 1788) in central Italy, we developed a structured decision making technique, based on a Bayesian Decision Network model and explicitly considering the plurality of environmental values of invasive species management to reduce potential social conflicts. RESULTS The model identified priority areas for management activities. These areas corresponded to the core of the grey squirrel range, but they also included peripheral zones, where rapid eradication is fundamental to prevent the spread of squirrels. However, when the model was expanded also integrating the attitude of citizens towards the project, the intervention strategy slightly changed. In some areas, the citizens’ support was limited and this resulted in a reduced overall utility of intervention. CONCLUSION The suggested approach extends the scientific basis for the management decisions, evaluated in terms of technical efficiency, feasibility and social impact. Here, the Bayesian Decision Network model analysed the potential technical and social consequences of management actions and it responded to the need of transparency in the decision process, but it can be easily extended to consider further issues, common in many mammal eradication programs. Thanks to its flexibility and comprehensiveness, it provides an innovative example of how to plan rapid eradication or control activities, as required by the new EU Regulation.
      PubDate: 2016-07-01T07:40:24.218874-05:
      DOI: 10.1002/ps.4352
       
  • Toxicity of squamocin on Aedes aegypti larvae, its predators and human
           cells
    • Abstract: BACKGROUND The mosquito Aedes aegypti transmit virus that cause diverse human diseases and the vector control is an important strategy to avoid their propagation. Plants in Annonaceae are recognized as source to molecules with use in medical and agriculture fields. Molecules of secondary metabolites of Annonaceae plants exhibit insecticidal potential against insect pest and vectors, with highlight to acetogenins that show high toxicity with low doses, which encouraged research to producing new insecticide molecules. Herein, we identify an acetogenin from Annona mucosa seeds (chemical analysis) and provide toxicity test against larvae of A. aegypti (target insect), its predators Culex bigoti and Toxorhynchites theobaldi (non‐target insects) and cytotoxicity to human leukocytes. RESULTS We identify squamocin (C37H66O7) a fatty acid with presence of bis‐tetrahydrofuran ring. In A. aegypti, this compound exhibited behavioral disturb before larval death, high mortality and require low concentrations to LC50 = 0.01 µg/mL and LC90 = 0.11 µg/mL. However, in predators and human leukocytes the squamocin showed non‐effect toxic which indicate selectivity this molecule to non‐target organism. CONCLUSION We identify squamocin from A. mucosa seeds and reported lethal action against A. aegypti and show that it is selective for non‐target insects and has low cytotoxicity on human cell.
      PubDate: 2016-07-01T07:35:40.975195-05:
      DOI: 10.1002/ps.4350
       
  • Studies toward Understanding the SAR around the Sulfoximine Moiety of the
           Sap‐Feeding Insecticide Sulfoxaflor
    • Authors: Ann M. Buysse; Benjamin M. Nugent, Nick X. Wang, Zoltan Benko, Nneka Breaux, Richard Rogers, Yuanming Zhu
      Abstract: BACKGROUND The discovery of sulfoxaflor (Isoclast™ active) stemmed from a novel scaffold‐based approach toward identifying bioactive molecules. It exhibits broad spectrum control of many sap‐feeding insect pests, including aphids, whiteflies, hoppers and Lygus. Systematic modifications of the substituents flanking each side of the sulfoximine moiety were carried out to determine if these changes would improve potency. RESULTS Structure activity relationship (SAR) studies showed that with respect to the methylene linker, both mono‐ and di‐substitution with alkyl groups of varying sizes as well as cyclic analogs exhibited excellent control of cotton aphids. However against green peach aphids a decrease in activity was observed with substituents larger than ethyl as well as larger cycloalkyl groups. At the terminal tail there appeared to be a narrow steric tolerance as well, with linear groups or small rings more active against green peach aphids than bulkier groups. CONCLUSIONS A novel series of compounds which explored the substituents flanking the sulfoximine moiety of sulfoxaflor were prepared and tested for bioactivity against cotton aphids and green peach aphids. SAR studies indicated that a decrease in green peach aphid potency was observed at the methylene linker as well as the terminal tail with bulkier substituents. A quantitative structure activity relationship (QSAR) analysis of the compounds revealed significant correlation of activity with two molecular descriptors, vol (volume of a molecule) and GCUT_SMR_3 (molar refractivity). This predictive model helps explain the observed activity with the various substituents.
      PubDate: 2016-07-01T07:35:37.990813-05:
      DOI: 10.1002/ps.4351
       
  • Unrelenting spread of the alien monk parakeet Myiopsitta monachus in
           Israel. Is it time to sound the alarm?
    • Abstract: BACKGROUND Monk parakeets, Myiopsitta monachus Boddaert are native to South America, but have established populations in North America, Europe, Africa and Asia. They are claimed to act as agricultural pests in their native range, and their communal stick nests may damage human infrastructure. Although several monk parakeet populations are present in the Mediterranean basin and temperate Europe, little empirical data are available on their population size and growth, distribution, and potential impact. We investigated the temporal and spatial dynamics of monk parakeets in Israel to assess their invasion success and potential impact on agriculture. RESULTS Monk parakeet populations are growing exponentially at a higher rate than that reported elsewhere. The current Israeli population of monk parakeets comprises approximately 1500 individuals. The distribution of the species has increased and shifted from predominantly urban areas to agricultural landscapes. CONCLUSIONS In Israel monk parakeet populations are growing fast and have dispersed rapidly from cities to agricultural areas. At present, reports of agricultural damage are scarce. A complete assessment of possible management strategies is urgently needed before the population becomes too large and widespread to allow for cost‐effective mitigation campaigns to be implemented.
      PubDate: 2016-07-01T07:35:32.584788-05:
      DOI: 10.1002/ps.4349
       
  • Toxicities and effects of insecticidal toxic baits to control Drosophila
           suzukii and Zaprionus indianus (Diptera: Drosophilidae)
    • Authors: Felipe Andreazza; Daniel Bernardi, Cleber A Baronio, Joel Pasinato, Dori E Nava, Marcos Botton
      Abstract: BACKGROUND Drosophila suzukii is a primary insect pest that causes direct damage to fruits with a thin epidermis such as strawberries, cherries, and blueberries. In strawberry fields, the co‐occurrence of D. suzukii and Zaprionus indianus has increased production losses. This study evaluated the toxicities and effects of insecticidal baits to control adults and larvae of both D. suzukii and Z. indianus. RESULTS Organophosphates (dimethoate and malathion), spinosyns (spinosad and spinetoram), pyrethroid (lambda‐cyhalothrin) and diamide (cyantraniliprole) insecticides, exhibited high toxicity to both adults and larvae of D. suzukii and Z. indianus (mortality > 80%) in topical and dip bioassays. However, when the insecticides were mixed with a feeding attractant, a positive effect was observed only for adults of D. suzukii. Insecticides containing neonicotinoids (acetamiprid and thiamethoxam) and pyrolle (chlorfenapyr) caused intermediate mortality to adults of D. suzukii (40% to 60%) and low mortality for Z. indianus (mortality 
      PubDate: 2016-06-29T02:45:21.460099-05:
      DOI: 10.1002/ps.4348
       
  • Enhancing the Effectiveness of Biological Control Programs of Invasive
           Species through a More Comprehensive Pest Management Approach
    • Authors: Joseph M DiTomaso; Robert A Van Steenwyk, Robert M Nowierski, Jennifer L Vollmer, Eric Lane, Earl Chilton, Patrick L Burch, Phil E. Cowan, Kenneth Zimmerman, Christopher P Dionigi
      Abstract: BACKGROUND Invasive species are one of the greatest economic and ecological threats to agriculture and natural areas in the US and the world. Among the available management tools, biological control provides one of the most economical and long‐term effective strategies for managing widespread and damaging invasive species populations of nearly all taxa. RESULTS Integrating biological control programs in a more complete integrated pest management approach that utilizes increased information and communication, post‐release monitoring, adaptive management practices, long‐term stewardship strategies, and new and innovative ecological and genetic technologies can greatly improve the effectiveness of biological control. In addition, expanding partnerships among relevant national, regional, and local agencies, as well as academic scientists and land managers, offers far greater opportunities for long‐term success in the suppression of established invasive species. CONCLUSIONS In this paper we direct our recommendations to federal agencies that oversee, fund, conduct research, and develop classical biological control programs for invasive species. By incorporating these recommendations into adaptive management strategies, private and public land managers will have far greater opportunities for long‐term success in suppression of established invasive species.
      PubDate: 2016-06-29T02:20:36.694577-05:
      DOI: 10.1002/ps.4347
       
  • Predation by generalist arthropod predators on Apolygus lucorum
           (Hemiptera: Miridae): molecular gut‐content analysis and field‐cage
           assessment
    • Authors: Jinhua Li; Fan Yang, Qian Wang, Hongsheng Pan, Haibin Yuan, Yanhui Lu
      Abstract: BACKGROUND The mirid bug Apolygus lucorum (Meyer‐Dür) is a principal pest of cotton that also causes great damage to many other crops in China. A study was conducted to assess the mortality of A. lucorum from generalist arthropod predators using both molecular methods and a field‐cage trial. The species‐specific primer pair for the detection of A. lucorum tissues in predators was designed according to the sequences of the cytochrome oxidase subunit I (COI) gene. RESULTS A total of 2096 generalist predators that consisted of ladybeetles, lacewings and spiders were collected, and A. lucorum remains were detected using the designed primers. Only 1.6% of these predators contained A. lucorum DNA, with the highest positive proportion (6.1%) for Harmonia axyridis larvae. In the field‐cage experiment, the daily predation rates of 2nd instar A. lucorum nymphs by H. axyridis adults and larvae were 4.7% and 5.2%, respectively. CONCLUSIONS The overall low positive proportion of generalist predators with A. lucorum DNA detected using the molecular method combined with the low predation rate in the field‐cage experiment indicated that the primary generalist predators likely had a limited role in the suppression of A. lucorum in the field.
      PubDate: 2016-06-28T03:40:20.209566-05:
      DOI: 10.1002/ps.4346
       
  • Insecticide ADME for Support of Early Phase Discovery: Combining Classical
           and Modern Techniques
    • Authors: Michael D. David
      Abstract: The two factors which determine an insecticide's potency are its binding to a target site (intrinsic activity) and the ability of its active form to reach the target site (bioavailability). Bioavailability is dictated by the compound's stability and transport kinetics, which are determined by both physical and biochemical characteristics. At BASF Global Insecticide Research, we characterize bioavailability in early research with an ADME (Absorption, Distribution, Metabolism, and Excretion) approach, combining classical and modern techniques. For biochemical assessment of metabolism, we purify native insect enzymes using classical techniques, and recombinantly express individual insect enzymes which are known to be relevant in insecticide metabolism and resistance. For analytical characterization of an experimental insecticide and its metabolites, we conduct classical radiotracer translocation studies when a radiolabel is available. In discovery, where typically no radiolabel has been synthesized, we utilize modern high‐resolution mass spectrometry to probe complex systems for the test compounds and its metabolites. By using these combined approaches, we can rapidly compare the ADME properties of sets of new experimental insecticides and aid in the design of structures with an improved potential to advance in the research pipeline.
      PubDate: 2016-06-27T03:45:34.207794-05:
      DOI: 10.1002/ps.4345
       
  • Potential risk levels of invasive Neoleucinodes elegantalis (small tomato
           borer) in areas optimal for open field Solanum lycopersicum (tomato)
           cultivation in the present and under predicted climate change
    • Abstract: BACKGROUND Neoleucinodes elegantalis is one of the major insect pests of Solanum lycopersicum. Currently N. elegantalis is present only in America and the Caribbean, and is a threat in the world's largest S. lycopersicum producing countries. In terms of potential impact on agriculture, the impact of climate change on insect invasions must be a concern. Currently no research exists regarding the effects of climatic change on risk level of N. elegantalis. The purpose of this study is to develop a model for S. lycopersicum and N. elegantalis utilizing CLIMEX to determine risk levels of N. elegantalis in open field S. lycopersicum cultivation in the present and under projected climate change, using the Global Climate Model, CSIRO‐Mk3.0. RESULTS Large areas are projected to be suitable for N. elegantalis and optimal for open field S. lycopersicum cultivation under current time. However, in the future these areas will become unsuitable for both species. Conversely, in others regions in the future may become optimal for open field S. lycopersicum cultivation with varying risk level for N. elegantalis. CONCLUSION The risk levels results presented here provide a useful tool to design strategies to prevent the introduction and establishment of N. elegantalis in open field S. lycopersicum cultivation.
      PubDate: 2016-06-22T03:30:33.595448-05:
      DOI: 10.1002/ps.4344
       
  • Impact of volunteer rice infestation on yield and grain quality of rice
    • Authors: Vijay Singh; Nilda R. Burgos, Shilpa Singh, David R. Gealy, Edward E. Gbur, Ana L. Caicedo
      Abstract: BACKGROUND Volunteer rice (Oryza sativa L.) grains may differ in physico‐chemical traits from cultivated rice, which may reduce the quality of harvested rice grain. To evaluate the effect of volunteer rice on cultivated rice, fields were surveyed in Arkansas, USA in 2012. RESULTS Cropping history that included hybrid cultivars in the previous two years (2010 and 2011) had higher volunteer rice infestation (20%) compared to fields planted previously with inbred rice (5.6%). The total grain yield of rice was reduced 0.4% for every 1% increase in volunteer rice density. The grain quality did not change in fields planted with the same cultivar for three years. Volunteer rice density of at least 7.6% negatively impacted the head rice yield. Volunteer rice density of at least 17.7% reduced the rice grain yield. The protein and amylose contents of rice were not affected until volunteer rice infestation exceeded 30%. CONCLUSION Crop rotation systems that include hybrid rice are expected to have higher volunteer rice infestation than systems without hybrid rice. It is predicted that at 8% infestation, volunteer rice will start to impact head rice yield and will reduce total yield at 18% infestation. It could alter the chemical quality of rice grain at >30% infestation.
      PubDate: 2016-06-22T03:30:30.546135-05:
      DOI: 10.1002/ps.4343
       
  • Behavioral effects of sublethal exposure to a combination of
           β‐cyfluthrin and imidacloprid in the bed bug, Cimex lectularius L
    • Authors: Sydney E. Crawley; Katelyn A. Kowles, Jennifer R Gordon, Michael F. Potter, Kenneth F. Haynes
      Abstract: BACKGROUND Bed bugs (Cimex lectularius) are blood‐feeding insect pests with public health relevance. Their rapid evolution of resistance to pyrethroids has prompted a shift to combination products that include both a pyrethroid and neonicotinoid insecticide. Insecticides have both a direct impact on mortality, and an indirect effect on behavior. Thus, we assessed the sublethal effects of a widely used combination product containing β‐cyfluthrin (a pyrethroid) and imidacloprid (a neonicotinoid), since unexpected behavioral changes after exposure have been known to affect efficacy of insecticides. RESULTS We found that bed bugs exposed to sublethal doses of a combination product containing β‐cyfluthrin and imidacloprid did not feed as effectively as untreated bugs. Their locomotion behavior was also reduced. However, aggregation in response to the presence of conspecific harborages was not affected by sublethal exposure. CONCLUSION Bed bugs exhibit behavioral changes after sublethal exposure to a combination product that could affect pest management choices and outcomes. A reduction in host‐finding efficiency and feeding could complement the lethal effects of the insecticide. Alternatively, reduced locomotion following exposure could limit ongoing contact with insecticide deposits. However, an overall reduction in movement indicates that treatments are unlikely to cause dispersal of bugs to adjacent dwellings.
      PubDate: 2016-06-20T09:31:17.433061-05:
      DOI: 10.1002/ps.4342
       
  • Delivery Strategies: RNA Interference in Agriculture and Human Health
    • Authors: Richard W. Heidebrecht
      Abstract: Crop protection through expression of introduced insecticidal proteins is a well‐established technique. Modifications of endogenous gene expression have also been used successfully to produce safe and effective agrochemical products. The existing gene expression regulatory apparatus can be employed to alter messenger ribonucleic acid (mRNA) stability in the host species through a ribonucleic acid‐interference (RNAi) mechanism. Such solutions are currently delivered by incorporation of new genes into the host plant. Direct delivery of RNAi is being extensively explored in the clinic to treat selected human diseases and could be advantageous in agriculture. What are the unifying characteristics of successful delivery agents, and how can we project those observations into the future?
      PubDate: 2016-06-17T06:11:09.389004-05:
      DOI: 10.1002/ps.4341
       
  • Expression pattern and pharmacological characterisation of two novel
           alternative splice variants of glutamate‐gated chloride channel in the
           small brown planthopper Laodelphax striatellus
    • Abstract: BACKGROUND Glutamate‐gated chloride channels (GluCl) mediate fast inhibitory neurotransmission in invertebrate nervous systems. Although only one GluCls gene was presented in insects, it showed diverse alternative splicing that was speculated could impact on channel function and pharmacology. RESULTS In this study, we isolated GluCl cDNAs from adult of the small brown planthopper (SBPH, Laodelphax striatellus) and showed that six L. striatellus GluCls variants (LsGluCl‐AS, LsGluCl‐BS, LsGluCl‐CS, LsGluCl‐AL, LsGluCl‐BL and LsGluCl‐CL) were present in the SBPH. The expression patterns of six variants differed among developmental stages (egg, 1st–5th instar nymph, male and female) and among the body parts (head, thorax, abdomen, and leg) of the female adult SBPH. All the transcripts were abundant in the head of the adult. When expressed in Xenopus laevis oocytes, the two functional variants (LsGluCl‐AS and ‐AL) had similar EC50 and IC50 values for L‐glutamate and channel blockers picrotoxinin and fipronil. CONCLUSION This study represents a comprehensive molecular, expression and pharmacological characterisation of GluCl in the SBPH. These findings should be useful in providing more opportunities to discover novel insect control chemicals.
      PubDate: 2016-06-15T03:45:25.801951-05:
      DOI: 10.1002/ps.4340
       
  • Survey for zoonotic pathogens in Norway rat populations from Europe
    • Abstract: BACKGROUND The Norway rat Rattus norvegicus is an important reservoir of various zoonotic pathogens, such as cowpox virus and Leptospira, but also for agents of no or unknown zoonotic potential. We describe a survey of 426 Norway rats originating from five European countries and different habitats for Leptospira spp., rickettsiae, orthopox virus (OPV), avian metapneumovirus subtype A and B (aMPV), and rat polyomavirus (rat PyV). RESULTS Leptospira DNA was detected in 60 of 420 (14.3%) rats and Rickettsia DNA was found in three of 369 (0.8%) rats investigated. PCR‐based typing resulted in the identification of L. interrogans sequence type 17, serogroup Icterohaemorrhagiae, and Rickettsia helvetica, respectively. Rat PyV DNA was detected in 103 of 421 (24.5%) rats. OPV DNA and aMPV RNA were detected in none of the rats, but OPV‐specific antibodies in three of 388 (0.8%) rats. The frequency of single Leptospira and rat PyV infections and co‐infections was, independent of sex, greater for adults compared to juveniles/subadults and greater at rural sites compared to urban areas. CONCLUSIONS Study results indicate a broad geographical distribution of Leptospira DNA in rats within Europe underlining the need to further investigate potential mechanisms leading to increased prevalence in rural habitats and to assess the relevance to public health. In contrast, rickettsia and OPV infections rarely occurred in wild rat populations. The potential influence of rat PyV on the susceptibility to infections with other pathogens should be investigated in future studies.
      PubDate: 2016-06-14T08:25:32.743798-05:
      DOI: 10.1002/ps.4339
       
  • A simple approach for a spatial terrestrial exposure assessment of the
           insecticide fenoxycarb based on a high resolution landscape analysis
    • Authors: Kai Thomas; Herbert Resseler, Robert Spatz, Paul Hendley, Paul Sweeney, Martin Urban, Roland Kubiak
      Abstract: BACKGROUND The objective was to refine the standard regulatory exposure scenario used in plant protection product authorisations by developing a more realistic landscape related GIS‐based exposure assessment for terrestrial Non‐Target Arthropods. We quantified the proportion of adjacent off‐target area in agricultural landscapes potentially exposed to insecticide drift from applications of the active substance fenoxycarb. High resolution imagery, landscape classification, and subsequent stepwise analysis of a whole landscape using drift and interception functions were applied to selected areas in representative fruit‐producing regions in Germany. RESULTS Even under worst‐case assumptions regarding treated area, use rate and drift, less than 12 % of the non‐agricultural habitat area would potentially be exposed to fenoxycarb drift above regulatory acceptable concentrations. Additionally, if the filtering effect of tall vegetation were taken into account, this number would decrease to 6.6 %. Further refinements to landscape elements and application conditions indicate that less than 5 % of the habitat area might be exposed above regulatory acceptable concentrations, meaning that 95 % of the non‐agricultural habitat area will be unimpacted (i.e., no unacceptable effects) and can serve as refuge for recolonisation. CONCLUSIONS Approaches and tools are proposed for standardizable and transparent refinements in regulatory risk assessments on landscape level.
      PubDate: 2016-06-14T08:25:28.81018-05:0
      DOI: 10.1002/ps.4338
       
  • RNAi‐based gene silencing through dsRNA injection or ingestion against
           
    • Authors: Katterinne Prentice; Olivier Christiaens, Ine Pertry, Ana Bailey, Chuck Niblett, Marc Ghislain, Godelieve Gheysen, Guy Smagghe
      Abstract: BACKGROUND RNA interference (RNAi) technology can potentially serve as a suitable strategy to control the African sweetpotato weevil Cylas puncticollis (SPW), which is a critical pest in Sub‐Saharan Africa. Important prerequisites are required to use RNAi in pest control, such as the presence of an efficient RNAi response and the identification of suitable target genes. RESULTS Here we evaluated the toxicity of dsRNAs targeting essential genes by injection and oral feeding in SPW. In injection assays, 12 of 24 dsRNAs were as toxic as the one targeting Snf7, a gene used commercially against Diabrotica virgifera virgifera. Three dsRNAs with high insecticidal activity were then chosen for oral feeding experiments. The data confirmed that oral delivery can elicit a significant toxicity, albeit lower compared to injection. Subsequently, ex vivo assays revealed that dsRNA is affected by degradation in the SPW digestive system, possibly explaining the lower RNAi effect by oral ingestion. CONCLUSION We conclude that the full potential of RNAi in SPW is affected by the presence of nucleases. Therefore, for future application in crop protection, it is necessary to either constantly provide new dsRNA and/or protect it against possible degradation to obtain a higher RNAi efficacy.
      PubDate: 2016-06-14T08:25:26.11771-05:0
      DOI: 10.1002/ps.4337
       
  • Lead Generation in Crop Protection Research: A Portfolio Approach to
           Agrochemical Discovery
    • Authors: Michael R. Loso; Negar Garizi, Vidyadhar B. Hegde, James E. Hunter, Thomas C. Sparks
      Abstract: The need for increased food and feed supply to support future global demand with the added challenges of resistance pressure and an evolving regulatory environment necessitate the discovery of new crop protection agents for growers of today and tomorrow. Lead generation is the critical “engine” for maintaining a robust pipeline of new high‐value products. A wide variety of approaches exist for the generation of new leads, many of which having demonstrated success. Each approach features some degree of merit or benefit while also having some inherent drawback or level of risk. While risk for any single approach can be mitigated in a variety of different ways depending on the approach, long‐term viability of a successful lead generation program merits utilization of a portfolio of different approaches and methodologies for the generation of new leads.
      PubDate: 2016-06-14T08:15:39.460503-05:
      DOI: 10.1002/ps.4336
       
  • Biological control of chestnut blight in Croatia: an interaction between
           host ‐ sweet chestnut, its pathogen Cryphonectria parasitica and the
           biocontrol agent ‐ Cryphonectria hypovirus 1
    • Abstract: BACKGROUND Chestnut blight, caused by the fungus Cryphonectria parasitica, is a severe chestnut disease which can be controlled with naturally occurring hypoviruses in many areas of Europe. The aim of this research was to measure effect of different Cryphonectria hypovirus 1 (CHV1) strains on the growth of fungal host and select strains that could potentially be used for human‐mediated biocontrol in forests and orchards, and to investigate if and how chestnut‐fungus‐virus interactions affect development and growth of lesion area on cut stems. RESULTS Two Croatian CHV1 strains (CR23 and M56/1) were selected as potential biocontrol agents. The sequencing of CHV1/ORF‐A showed that both of these virus strains belonged to the Italian subtype of CHV1. In vitro transfection of selected virus strains from hypovirulent to genetically diverse virus‐free fungal isolates and subsequent inoculation of all virus/fungus combinations on stems of genetically diverse sweet chestnut trees revealed that Croatian virus strain CR23 had an equally hypovirulent effect on the host as the strong French strain CHV1‐EP713, while M56/1 had a weaker effect. Furthermore, it was shown that in some cases, the same hypovirus‐fungus combinations induced various degrees of canker development on different chestnut genotypes. CONCLUSION Some CHV1 strains belonging to the Italian subtype have similar hypovirulent effects on C. parasitica as those belonging to the French subtype. Furthermore, chestnut susceptibility and recovery could be influenced by the response of chestnut trees to particular hypovirulent C. parasitica isolates, and virus‐fungus‐chestnut interactions could have significant implications on the success of chestnut blight biocontrol.
      PubDate: 2016-06-11T01:20:28.907136-05:
      DOI: 10.1002/ps.4335
       
  • Genetics, cross‐resistance and synergism of indoxacarb resistance in
           Helicoverpa armigera (Lepidoptera: Noctuidae)
    • Authors: L.J. Bird
      Abstract: BACKGROUND The cotton bollworm Helicoverpa armigera is a global pest of field and horticultural crops and has developed resistance to insecticides from many chemical classes. Indoxacarb is an important option for selective control of H. armigera in a range of crops that play host to this species. A strain of H. armigera resistant to indoxacarb (designated GY7‐39) was detected from the field by F2 screening and characterized by comparison with a near‐isogenic indoxacarb‐susceptible laboratory strain to determine inheritance, cross‐resistance profile, and synergism of indoxacarb resistance. RESULTS The level of indoxacarb resistance in the GY7‐39 was 139 to 198‐fold compared with the susceptible strain. Genetic analysis showed that resistance was autosomal, incompletely dominant, and conferred by one or a few closely linked loci. Indoxacarb resistance in the GY7‐39 strain did not confer cross‐resistance to chlorantraniliprole. The GY7‐39 was more susceptible to emamectin benzoate, fenvalerate, Cry1Ac and Cry2Ab compared with the susceptible strain. Indoxacarb resistance was synergized by the metabolic inhibitor PBO. CONCLUSIONS Rapid selection of indoxacarb resistance in the GY7‐39 strain indicates the potential risk of resistance development to indoxacarb in field populations of H. armigera. Lack of cross‐resistance indicates that resistance could be managed effectively by the use of rotational strategies which incorporate transgenic technologies. Synergism studies indicate the potential involvement of metabolic detoxification enzymes as the mechanism of resistance to indoxacarb.
      PubDate: 2016-06-10T04:45:23.863541-05:
      DOI: 10.1002/ps.4334
       
  • Development and implementation of a laboratory spray device and rainfall
           simulator for retention research using small amounts of
           agro‐formulations
    • Authors: Ingrid K. A. Zwertvaegher; Inge Van Daele, Peter Verheesen, Marnix Peferoen, David Nuyttens
      Abstract: BACKGROUND Rainfall greatly affects the retention of foliar‐applied agro‐formulations. Improving their resistance to wash‐off is therefore of great importance in spray applications. While developing such formulations, small‐scale laboratory assays are generally required. A set‐up for retention studies using only small amounts of agro‐formulations (< 0.5 L) was developed. The set‐up consists of a spray device and a rainfall simulator. The effect of rain quantity (1, 3, 6 mm) on the spray retention of agro‐formulations was evaluated using this set‐up. RESULTS The data showed that uniform and repeatable spraying was achieved with the small‐scale spray device (CV = 23.4%) on potato pot plants (Solanum tuberosum L.). Rain quantity significantly affected the spray retention. Approximately 40% of the initial deposition was lost after 1 mm of rain at an intensity of 25 mm h−1. Additional losses decreased with increasing volumes of rain (65% and 80% loss after respectively 3 mm and 6 mm of rain). CONCLUSION Future studies could implement the set‐up to evaluate the effect of different rainfall characteristics and formulations on spray retention in order to improve the rainfastness of agro‐formulations.
      PubDate: 2016-06-10T04:22:26.578971-05:
      DOI: 10.1002/ps.4333
       
  • Wheat (Triticum aestivum L.)‐based intercropping systems for
           biological pest control: a review
    • Abstract: BACKGROUND Wheat Triticum aestivum L.) is one of the most cultivated crops in temperate climates. As its pests are mainly controlled with insecticides which are harmful to the environment and human health, alternative practices such as intercropping have been studied for their potential to promote biological control. Based on the published literature, this study aimed to review the effect of wheat‐based intercropping systems on insect pests and their natural enemies. RESULTS Fifty original research papers were obtained from a systematic search of the peer‐reviewed literature. Results from a vote‐counting analysis indicated that, in the majority of studies, pest abundance was significantly reduced in intercropping systems compared with pure stands. However, the occurrence of their natural enemies as well as predation and parasitism rates were not significantly increased. The country where the studies took place, the type of intercropping, and the crop that was studied in the association had significant effects on these results. CONCLUSION These findings show that intercropping is a viable practice to decrease insecticide use in wheat production systems. Nevertheless, other practices could be combined with intercropping to favour natural enemies and enhance pest control.
      PubDate: 2016-06-08T04:21:18.46591-05:0
      DOI: 10.1002/ps.4332
       
  • Lipopeptides from a novel Bacillus methylotrophicus 39b strain suppress
           Agrobacterium crown gall tumours on tomato plants
    • Abstract: BACKGROUND This study aims to characterize the antibacterial activity of a novel Bacillus methylotrophicus strain named 39b against tumorigenic Agrobacterium tumefaciens C58 and B6 strains. It also aims to identify the compound which is responsible for its activity and to evaluate its efficiency to control crown gall disease in tomato plants. RESULTS B. methylotrophicus strain 39b was found to stop the growth of phytopathogenic A. tumefaciens strains in in vitro experiments. Lipopeptides; surfactins, iturins and fengycins; were detected under various isoforms, by mass spectrometry analysis of the methanolic extract. The active principle acting against Agrobacterium strains was isolated from TLC plates and identified by mass spectrometry as surfactin. The strain was effective in reducing the weight and the number of galls induced by A. tumefaciens strains on tomato plants. Total inhibition of gall formation was observed using the antibacterial compounds. CONCLUSION B. methylotrophicus strain 39b exhibited antibacterial activity against phytopathogenic A. tumefaciens C58 and B6 both in vitro and in vivo. Lipopeptides are the main compounds which confer the biocontrol ability. This strain has the potential to be developed as a biological control agent for crown gall disease.
      PubDate: 2016-06-02T01:40:30.090684-05:
      DOI: 10.1002/ps.4331
       
  • Review of anthraquinone applications for pest management and agricultural
           crop protection
    • Authors: Shelagh T. DeLiberto; Scott J. Werner
      Abstract: We reviewed published anthraquinone applications for international pest management and agricultural crop protection from 1943–2016. Anthraquinone (AQ) is commonly found in dyes, pigments, and many plants and organisms. Avian repellents research with AQ began in the 1940s. In context of pest management, AQ is currently used as a chemical repellent, perch deterrent, insecticide, and feeding deterrent in many wild birds, and some mammals, insects, and fishes. Criteria for evaluation of effective chemical repellents include efficacy, potential for wildlife hazards, phytotoxicity, and environmental persistence. As a biopesticide, AQ often meets these criteria of efficacy for the non‐lethal management of agricultural depredation caused by wildlife. We summarize published applications of AQ for the protection of newly‐planted and maturing crops from pest birds. Conventional applications of AQ‐based repellents include pre‐plant seed treatments (e.g. corn (Zea mays L.), rice (Oryza sativa L.), sunflower (Helianthus annuus L.) wheat (Triticum spp.), millet (Panicum spp.), sorghum (Sorghum bicolor L.), pelletized feed, and forest tree species) and foliar applications for rice, sunflower, lettuce (Lactuca sativa L.), turf, sugar beets (Beta vulgaris L.), soybean (Glycine max L.), sweet corn, and nursery, fruit, and nut crops. In addition to agricultural‐repellent applications, AQ has also been used to treat toxicants for the protection of non‐target birds. Few studies have demonstrated AQ repellency in mammals, including wild boar (Sus scrofa, L.), thirteen‐lined ground squirrels (Ictidomys tridecemlineatus, Mitchill), black‐tailed prairie dogs (Cyomys ludovicainus, Ord.), common voles (Microtus arvalis, Pallas), house mice (Mus musculus, L.), Tristram's jirds (Meriones tristrami, Thomas) and black rats (Rattus rattus L.). Natural sources of AQ and its derivatives have also been identified as insecticides and insect repellents. As a natural or synthetic biopesticide, AQ is a promising candidate for many contexts of non‐lethal and insecticidal pest management.
      PubDate: 2016-06-02T01:35:30.42667-05:0
      DOI: 10.1002/ps.4330
       
  • Evolution of resistance to pyrethroid insecticides in Musca domestica
    • Authors: Jeffrey G. Scott
      Abstract: BACKGROUND House flies, Musca domestica L., are a significant pest because of the numerous diseases they transmit. Control of house fly populations, particularly at animal production facilities, is frequently done using pyrethroid insecticides which kill insects by prolonging the open time of the voltage sensitive sodium channel (VSSC). RESULTS House flies have evolved resistance to pyrethroids due to mutations in Vssc and by cytochrome P450‐mediated detoxification. Three Vssc mutations are known: kdr (L1014F), kdr‐his (L1014H) and super‐kdr (M918T+L1014F). Generally, the levels of resistance conferred by these mutations are kdr‐his < kdr < super‐kdr, but this pattern does not hold for multi‐halogenated benzyl pyrethroids for which super‐kdr confers less resistance than kdr. P450‐mediated resistance can result from overexpression of CYP6D1 or to another P450 (unidentified) whose overexpression is linked to autosomes II or V. CONCLUSIONS The initial use of field‐stable pyrethroids resulted in different patterns of evolution across the globe, but with time these mutations have become more widespread in their distribution. What is known about the fitness costs of the resistance alleles in the absence of insecticide is discussed, particularly with respect to the current and future utility of pyrethroid insecticides.
      PubDate: 2016-05-31T02:00:41.407397-05:
      DOI: 10.1002/ps.4328
       
  • Field evaluation of the nematicide fluensulfone for control of the potato
           cyst nematode Globodera pallida
    • Authors: Patrick M Norshie; Ivan G Grove, Matthew A Back
      Abstract: BACKGROUND Three field experiments evaluated the performance of the nematicide fluensulfone against the potato cyst nematode Globodera pallida in Shropshire, England. RESULTS Experiments 1 and 2 showed reduced root infection and lowered multiplication of G. pallida following fluensulfone (Nimitz 15G®) soil treatments at five rates (1.95, 3.00, 4.05 (full rate), 5.05 and 6.00 kg a.s. ha−1), and Nimitz 480EC® at the full rate. Experiment 3 demonstrated a positive interaction between the full rate of Nimitz 15G® and the potato variety Santé in the reduction of G. pallida. The fluensulfone treatments at the full rate had more consistent effects than the lower rates, and there were no greater effects for the treatments higher than this full rate. Generally, fluensulfone was less efficacious than oxamyl or fosthiazate, which suggests that the treatment may not be reliably integrated within shorter potato rotations CONCLUSION The data suggest that fluensulfone soil application could make a useful addition to the few available nematicide treatments for the control of G. pallida rather than be a substitute for these treatments.
      PubDate: 2016-05-31T02:00:36.604497-05:
      DOI: 10.1002/ps.4329
       
  • Susceptibility of Alphitobius diaperinus in Texas to permethrin and
           β‐cyfluthrin treated surfaces
    • Authors: Brandon N. Lyons; Tawni L. Crippen, Le Zheng, Pete D. Teel, Sonja L. Swiger, Jeffery K. Tomberlin
      Abstract: BACKGROUND Effective control of the lesser mealworm beetle, Alphitobius diaperinus, relies heavily on insecticides. Susceptibility level of beetles to these insecticides can be dependent on active ingredient, population treated, formulation, surface treated and timing of observation. The susceptibility of adult beetles from six populations to β‐cyfluthrin was determined up to 48 hours after exposure. Susceptibility of adult beetles to the label rate of β‐cyfluthrin and permethrin formulations on concrete, wood chip‐type particleboard, and pressure treated wood was determined up to 48 hours post exposure. RESULTS Variation in LC50’s at 2 and 24 hours were found within and between beetle populations from two regions of Texas, USA sampled at 2 and 24 h. The permethrin formulation had lower mean mortality than the β‐cyfluthrin formulation on all surfaces tested. The permethrin formulation had high levels of recovery on all surfaces tested after 2 h. Surface affected the efficacy of the insecticides tested on killing adult beetles. CONCLUSION Permethrin‐based insecticide had lower knockdown and persistence on various surfaces over time than β‐cyfluthrin‐based insecticide. Beetle recovery in less‐ susceptible populations may necessitate longer observation periods for efficacy evaluations. Our study also shows that surfaces chosen can affect efficacy of the compound on killing adult beetles.
      PubDate: 2016-05-30T15:45:25.499968-05:
      DOI: 10.1002/ps.4327
       
  • Long‐term population patterns of rodents and associated damage in
           German forestry
    • Abstract: BACKGROUND Several rodent species can damage forest trees especially at young tree age in afforestation. Population outbreaks of field voles (Microtus agrestis L.) and bank voles (Myodes glareolus Schreber) in particular can cause losses. RESULTS Analyses of long‐term time‐series indicate good synchrony of population abundance in rodent species associated with damage in forestry. This synchrony could be related to the effect of beech (Fagus spec.) mast in the previous year on population growth rates of both species. In shorter time‐series from Eastern Germany, damage in forestry was mostly associated with autumn abundances of rodents. Environmental factors like beech mast and snow cover did not explain additional variation in rodent damage to trees. CONCLUSIONS Beech mast is a good indicator of long‐term rodent abundance in Northern German afforestation areas. However, rodent damage to forestry in Central Germany did not seem to depend on environmental parameters other than rodent abundance at the large scale. As a result, there is still uncertainty on the link between environmental predictors and rodent damage to forestry and further experimental work is required to identify suitable environmental drivers and their interplay with other potential factors such as the local predator community.
      PubDate: 2016-05-28T01:20:29.581305-05:
      DOI: 10.1002/ps.4325
       
  • Sublethal dose of Phoxim and Bombyx mori nucleopolyhedrovirus interact to
           elevate silkworm mortality
    • Authors: ZhiYa Gu; FanChi Li, JingSheng Hu, Chao Ding, Zhaoqian Wang, JiangHai Tian, Bin Xue, KaiZun Xu, WeiDe Shen, Bing Li
      Abstract: BACKGROUND Silkworm (Bombyx mori) is an economically important insect. It is relatively less resistant to certain chemicals and environment exposures, such as pesticides and pathogens. After pesticide exposures, the silkworms are more susceptible to microbial infections. The mechanism underlying the susceptibility might be related to immune response and oxidative stress. RESULTS Sublethal dose of phoxim combined with Bombyx mori nucleopolyhedrovirus (BmNPV) elevated the silkworm mortality at 96 h. We found higher content of H2O2 and increased levels of genes related to oxidative stress and immune response after treatment with sublethal dose of phoxim for 24 h or 48 h. However, such response decreased with longer pesticide treatment. The mortality increased 44% when B. mori was exposed to combined treatment with BmNPV and phoxim than BmNPV alone. The level of examined immune‐related and oxidative stress‐related genes significantly decreased in combined treatment group than those in BmNPV group. Our results indicated that with long‐term exposure to pesticides, such as OPs even at sublethal dose, the oxidative stress response and immune responses in silkworm were inhibited, which may lead to further immune impairment and accumulation of oxidative stress, resulting in the susceptibility to virus and harm to silkworm. CONCLUSION Our study provided insights for understanding the susceptibility to pathogen after pesticide exposures, which may promote the development of better pesticide controls to avoid significant economic losses.
      PubDate: 2016-05-25T01:45:27.684546-05:
      DOI: 10.1002/ps.4326
       
  • Phthalimide‐Derived Strigolactone Mimics as Germinating Agents for
           Seeds of Parasitic Weeds
    • Abstract: BACKGROUND Broomrapes attack important crops, cause severe yield losses and they are difficult to eliminate because their seed bank is virtually indestructible. In the absence of a host, the induction of seed germination leads to inevitable death due to nutrient starvation. Synthetic analogs of germination‐inducing factors may constitute a cheap and feasible strategy to control the seed bank. These compounds should be easy and cheap to synthesize as this will allow their mass production. The aim of this work is to obtain new synthethic germinating agents. RESULTS Nineteen N‐substituted phthalimides containing a butenolide ring and different substituents in the aromatic ring were synthesized. The synthesis started with commercially available phthalimides. The complete collection was assayed against the parasitic weeds Orobanche minor, O. cumana, Phelipanche ramosa and P. aegyptiaca, with the synthetic strigolactone analog GR24 used as a positive control. This compounds offered low EC50 values: O. cumana 38.3 μM, O. minor 3.77 μM, P. aegyptiaca 1.35 μM and P. ramosa 1.49 μM. CONCLUSIONS The synthesis was carried out in few steps and provided the target compounds in good yields. The compounds tested showed great selectivity and low EC50 values were obtained for structures that were simpler than GR24.
      PubDate: 2016-05-24T02:16:28.007957-05:
      DOI: 10.1002/ps.4323
       
  • The consequences of sublethal exposure to insecticide on the survivorship
           and mobility of Halyomorpha halys (Hemiptera: Pentatomidae)
    • Authors: William R. Morrison III; Brittany Poling, Tracy C. Leskey
      Abstract: BACKGROUND The direct lethal effects of conventional and organic insecticides have been investigated thoroughly for all life stages of H. halys. However, the sublethal effects of insecticides on the behavior of H. halys have not been well‐documented. Our aims were to evaluate the impact of a brief 5‐min exposure to residues of bifenthrin, dinotefuran, methomyl, thiamethoxam, and thiamethoxam + λ‐cyhalothrin on survivorship, horizontal and vertical movement, and flight capacity of adult H. halys under laboratory conditions. RESULTS Over half of the insecticide‐exposed adults were classified as affected, moribund, or dead after the 5‐min exposure, compared with only 6% of the adults in the water‐only control. We found that the horizontal movement, vertical climbing, and flight capacity of adults exposed to insecticides were decreased by 20‐60% overall relative to the water‐only control. The most lethal insecticide was bifenthrin. CONCLUSION Many insecticide‐exposed H. halys adults retained significant mobility and flight capacity, with flight most pronounced immediately after exposure. These results suggest that brief exposure periods to efficacious insecticides will result in high dispersal and low mortality. Therefore, management strategies that enhance the retention of H. halys on insecticide‐coated surfaces should be considered to ensure adults are exposed to a lethal dose of insecticide.
      PubDate: 2016-05-23T01:55:27.295989-05:
      DOI: 10.1002/ps.4322
       
  • Sugar Concentration in Nectar: A Quantitative Metric of Crop
           Attractiveness for Refined Pollinator Risk Assessments
    • Authors: Loren D. Knopper; Tereza Dan, Dominic D. Reisig, Josephine D. Johnson, Lisa M. Bowers
      Abstract: Those involved with pollinator risk assessment know that agricultural crops vary in attractiveness to bees. Intuitively this means that exposure to agricultural pesticides is likely greatest for attractive plants and lowest for unattractive plants. While crop attractiveness in the risk assessment process has been qualitatively remarked on by some authorities, absent is direction on how to refine the process with quantitative metrics of attractiveness. At a high level, attractiveness of crops to bees appears to depend on several key variables, including but not limited to: floral, olfactory, visual and tactile cues, seasonal availability, physical and behavioral characteristics of the bee and plant, and nectar rewards. Notwithstanding the complexities and interactions amongst these variables, sugar content in nectar stands out as a suitable quantitative metric by which to refine pollinator risk assessments for attractiveness. Provided herein is a proposed way to use sugar nectar concentration to adjust the exposure parameter (with what is called a Crop Attractiveness Factor) in the calculation of risk quotients in order to derive crop‐specific Tier I assessments. This Perspective is meant to invite discussion on incorporating such changes in the risk assessment process.
      PubDate: 2016-05-20T02:11:11.637034-05:
      DOI: 10.1002/ps.4321
       
  • 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
       
  • 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
       
  • Not in my backyard: effectiveness of outdoor residual spraying from
           
    • 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
       
  • 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
       
  • 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
       
  • 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
       
  • Issue Information ‐ Aims and Scope
    • Pages: 1803 - 1803
      PubDate: 2016-08-09T02:44:38.554054-05:
      DOI: 10.1002/ps.4134
       
  • Issue Information ‐ Info Page
    • Pages: 1804 - 1804
      PubDate: 2016-08-09T02:44:36.101061-05:
      DOI: 10.1002/ps.4135
       
  • Issue Information ‐ ToC
    • Pages: 1805 - 1806
      PubDate: 2016-08-09T02:44:38.886379-05:
      DOI: 10.1002/ps.4136
       
  • Efficacy of SDHI fungicides, including benzovindiflupyr, against
           Colletotrichum species
    • Authors: Hideo Ishii; Fan Zhen, Mengjun Hu, Xingpeng Li, Guido Schnabel
      Pages: 1844 - 1853
      Abstract: BACKGROUND Colletotrichum species cause anthracnose diseases on many plants and crops. A new generation of succinate dehydrogenase inhibitors (SDHIs) was developed recently. The inhibitory activity of the five SDHI fungicides against Colletotrichum species was determined in this study. RESULTS Isolates of C. gloeosporioides, C. acutatum, C. cereale and C. orbiculare were insensitive (naturally resistant) to boscalid, fluxapyroxad and fluopyram on YBA agar medium. In contrast, these isolates were relatively sensitive to penthiopyrad, except for C. orbiculare. Most interestingly, benzovindiflupyr showed highest inhibitory activity against all of these four species. Benzovindiflupyr was effective against C. gloeosporioides and C. acutatum on apple and peach fruit, as well as on cucumber plants inoculated with C. orbiculare. The sdhB, sdhC and sdhD genes encoding the subunits of fungicide‐targeted succinate dehydrogenase were sequenced, but, despite high polymorphisms, no apparent resistance mutations were found in Colletotrichum species. CONCLUSIONS This is the first report on the activity of benzovindiflupyr against Colletotrichum species. The broad‐spectrum efficacy of benzovindiflupyr within the Colletotrichum genus might be exploited when designing disease management strategies against various pathogens on a wide range of crops. Other mechanism(s) than fungicide target‐site modification may be responsible for differential sensitivity of Colletotrichum species to SDHI fungicides. © 2016 Society of Chemical Industry
      PubDate: 2016-02-09T04:21:44.580694-05:
      DOI: 10.1002/ps.4216
       
  • Real‐time PCR assay to detect brown marmorated stink bug, Halyomorpha
           halys (Stål), in environmental DNA
    • Authors: Rafael E Valentin; Brooke Maslo, Julie L Lockwood, John Pote, Dina M Fonseca
      Pages: 1854 - 1861
      Abstract: BACKGROUND Early detection before establishment and identification of key predators are time‐honored strategies towards effective eradication or control of invasive species. The brown marmorated stink bug (BMSB), Halyomorpha halys, is a recent exotic pest of several important crops in North America and Europe. Resulting widespread applications of insecticides have countered years of careful integrated pest management and are leading to the resurgence of other agricultural pests. Environmental DNA (eDNA) has been used effectively to detect aquatic invasives. RESULTS We developed a real‐time PCR (qPCR) assay for BMSB in a conserved region of the ribosomal DNA interspacer 1 (ITS1). We validated this assay on worldwide populations of BMSB and tested its specificity and sensitivity against other US Pentatomidae species and on guano of big brown bat, Eptesicus fuscus, which we confirmed is a BMSB predator in New Jersey. We also detected BMSB DNA after rapid (and inexpensive) HotSHOT DNA extractions of soiled paper from cages briefly holding BMSB, as well as from discarded exuviae. CONCLUSION Given the high sensitivity of our assay to BMSB environmental DNA (eDNA) in terrestrial samples, this tool should become a cost‐effective approach for using eDNA to detect terrestrial invasive species and their key predators. © 2016 Society of Chemical Industry
      PubDate: 2016-02-08T04:07:31.599454-05:
      DOI: 10.1002/ps.4217
       
  • Glyphosate residues in rural groundwater, Nottawasaga River Watershed,
           Ontario, Canada
    • Authors: Dale R Van Stempvoort; John Spoelstra, Natalie D Senger, Susan J Brown, Ryan Post, John Struger
      Pages: 1862 - 1872
      Abstract: BACKGROUND The objective of this study was to investigate the occurrence of glyphosate residues (glyphosate and its metabolite AMPA) in shallow groundwater in a catchment dominated by agriculture, and to examine the potential for this groundwater to store and transmit these compounds to surface waters. RESULTS Glyphosate residues were found in some of the groundwater samples collected in riparian (surface seeps), upland (mostly
      PubDate: 2016-02-08T04:30:31.210383-05:
      DOI: 10.1002/ps.4218
       
  • Natural and synthetic vocalizations of brown rat pups, Rattus norvegicus,
           enhance attractiveness of bait boxes in laboratory and field experiments
    • Pages: 1873 - 1882
      Abstract: BACKGROUND Rats are often neophobic and thus do not readily enter trap boxes which are mandated in rodent management to help reduce the risk of accidental poisoning or capture of non‐target animals. Working with brown rats, Rattus norvegicus, as a model species, our overall objective was to test whether sound cues from pups could be developed as a means to enhance captures of rats in trap boxes. RESULTS Recording vocalizations from three‐day‐old pups after removal from their natal nest with both sonic and ultrasonic microphones revealed frequency components in the sonic range (1.8–7.5 kHz) and ultrasonic range (18–24 kHz, 33–55 kHz, 60–96 kHz). In two‐choice laboratory bioassays, playback recordings of these vocalizations induced significant phonotactic and arrestment responses by juvenile, subadult and adult female and male rats. The effectiveness of engineered ‘synthetic’ rat pup sounds was dependent upon their frequency components, sound durations and the sound delivery system. Unlike other speakers, a piezoelectric transducer emitting sound bursts of 21 kHz with a 63‐KHz harmonic, and persisting for 20–300 ms, proved highly effective in attracting and arresting adult female rats. In a field experiment, a battery‐powered electronic device fitted with a piezoelectric transducer and driven by an algorithm that randomly generated sound cues resembling those recorded from rat pups and varying in fundamental frequency (19–23 kHz), duration (20–300 ms) and intermittent silence (300–5000 ms) significantly enhanced captures of rats in trap boxes baited with a food lure and soiled bedding material of adult female rats. CONCLUSION Our study provides proof of concept that rat‐specific sound cues or signals can be effectively reproduced and deployed as a means to enhance capture of wild rats. © 2016 Society of Chemical Industry
      PubDate: 2016-02-16T04:44:15.763793-05:
      DOI: 10.1002/ps.4219
       
  • Larvicidal activity of natural and modified triterpenoids against Aedes
           aegypti (Diptera: Culicidae)
    • Authors: Gloria NS da Silva; Frances TT Trindade, Francine dos Santos, Grace Gosmann, Alexandre A e Silva, Simone CB Gnoatto
      Pages: 1883 - 1887
      Abstract: BACKGROUND Insecticide resistance to commonly used substances demands new molecules for the chemical control of the dengue vector Aedes aegypti. Because natural product sources have been an alternative to obtain larvicidal compounds, the aim of this study was to evaluate the triterpenoids betulinic (BA) and ursolic (UA) acids and their semi‐synthetic derivatives against larval Ae. aegypti. BA, UA, ten derivatives modified at the C‐3 position and a positive control (diflubenzuron) were evaluated. Larvicidal assays were carried out with early fourth‐instar larvae, and mortality was observed between 48 and 96 h. Doses from 200 to 10 ppm were used to calculate lethal concentrations (LCs). RESULTS Natural compounds, i.e. UA and BA, had the lowest LCs (LC50 of 112 and 142 ppm respectively), except for the modified compound 2b (LC50 of 130 ppm). Larvicidal activity increased significantly from 48 to 96 h for all the compounds evaluated, ranging from 20 to 50% after 48 h and from 48 to 76% after 96 h. Some derivatives, e.g. 2a and 2d, had up to a three‐fold larvicidal activity increase from 48 to 96 h. CONCLUSION BA, UA and their derivatives showed larvicidal activity against Ae. aegypti larvae, increasing significantly from 48 to 96 h. The presence of a hydroxyl group is essential for larvicidal potential in these triterpenoids. © 2016 Society of Chemical Industry
      PubDate: 2016-02-17T05:27:41.720071-05:
      DOI: 10.1002/ps.4221
       
  • Sensor‐based variable‐rate fungicide application in winter
           wheat
    • Pages: 1888 - 1896
      Abstract: BACKGROUND Currently, no technology for the automatic detection of diseases while moving agricultural equipment through fields is available on the market. An alternative approach of 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 operate the dosing system (gauge) at the field boom sprayer. A total of 8% of spray liquid was saved compared with common uniform spraying. CONCLUSIONS Because no differences exist in 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. © 2016 Society of Chemical Industry
      PubDate: 2016-03-07T04:49:28.181684-05:
      DOI: 10.1002/ps.4225
       
  • Neonicotinoid concentrations in UK honey from 2013
    • Authors: Ainsley Jones; Gordon Turnbull
      Pages: 1897 - 1900
      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 nor its metabolites were detected in any honey samples. Concentrations of clothianidin ranged from
      PubDate: 2016-02-23T03:52:12.840116-05:
      DOI: 10.1002/ps.4227
       
  • Foliar application of microdoses of sucrose to reduce codling moth Cydia
           pomonella L. (Lepidoptera: Tortricidae) damage to apple trees
    • Pages: 1901 - 1909
      Abstract: BACKGROUND The effects of foliar applications of microdoses of sucrose to reduce the damage by 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 granulovirus 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's efficacy of 41.0 ± 10.0%. This involved the induction of resistance by antixenosis to insect egg laying. Indeed, it seems that acceptance of egg laying on leaves treated with sucrose was reduced. The addition of sucrose to thiacloprid improved its efficacy (59.5% ± 12.8) by 18.4%. However, the sucrose had no added value when associated with C. pomonella granulovirus treatments. CONCLUSION Foliar applications of microdoses of sucrose every 20 days in commercial orchards can partially protect against the codling moth. Its addition to thiacloprid increases the efficacy in integrated control strategies, contrary to C. pomonella granulovirus treatments. This work opens a route for the development of new biocontrol strategies. © 2016 Society of Chemical Industry
      PubDate: 2016-02-25T03:41:27.356045-05:
      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
    • Pages: 1910 - 1925
      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 with an ACCase‐inhibiting one, resistant mutants exceeded 1 plant m−2, 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 mouldboard ploughing delayed resistance indefinitely in 90 and 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. © 2016 Society of Chemical Industry
      PubDate: 2016-02-19T06:43:47.515545-05:
      DOI: 10.1002/ps.4230
       
  • Leaf‐morphology‐assisted selection for resistance to two‐spotted
           spider mite Tetranychus urticae Koch (Acari: Tetranychidae) in carnations
           (Dianthus caryophyllus L)
    • Authors: Kousuke Seki
      Pages: 1926 - 1933
      Abstract: BACKGROUND The development of a cultivar resistant to the two‐spotted spider mite has provided both ecological and economic benefits to the production of cut flowers. This study aimed to clarify the mechanism of resistance to mites using an inbred population of carnations. RESULTS In the resistant and susceptible plants selected from an inbred population, a difference was recognised 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 a cultivar that is resistant to mites under a real cultivation environment by observing the internal structure of the leaf. © 2016 Society of Chemical Industry
      PubDate: 2016-03-03T07:54:02.827596-05:
      DOI: 10.1002/ps.4231
       
  • Frankliniella fusca resistance to neonicotinoid insecticides: an emerging
           challenge for cotton pest management in the eastern United States
    • Pages: 1934 - 1945
      Abstract: BACKGROUND Over the past two decades, neonicotinoid seed treatments have become the primary method to manage tobacco thrips, Frankliniella fusca Hinds, on seedling cotton. Because this insect is highly polyphagous and the window of insecticide exposure is short, neonicotinoid resistance was expected to pose a minimal risk. However, reports of higher than expected F. fusca seedling damage in seed‐treated cotton fields throughout the Mid‐South and Southeast US production regions suggested neonicotinoid resistance had developed. To document this change, F. fusca populations from 86 different locations in the eastern United States were assayed in 2014 and 2015 for imidacloprid and thiamethoxam resistance to determine the extent of the issue in the region. RESULTS Approximately 57 and 65% of the F. fusca populations surveyed had reduced imidacloprid and thiamethoxam sensitivity respectively. Survivorship in diagnostic bioassays was significantly different at both the state and regional scales. Multiple‐dose bioassays conducted on 37 of the populations documented up to 55‐ and 39‐fold resistance ratios for imidacloprid and thiamethoxam respectively. CONCLUSION Estimates of neonicotinoid resistance indicate an emerging issue for management of F. fusca in the eastern United States. Significant variation in survivorship within states and regions indicated that finer‐scale surveys were needed to determine factors (genetic, insecticide use) driving resistance evolution. © 2016 Society of Chemical Industry
      PubDate: 2016-02-15T05:50:41.368007-05:
      DOI: 10.1002/ps.4232
       
  • 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
      Pages: 1946 - 1950
      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 M. 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. © 2016 Society of Chemical Industry
      PubDate: 2016-02-18T02:32:49.348665-05:
      DOI: 10.1002/ps.4234
       
  • Establishment of polyethylene‐glycol‐mediated protoplast
           transformation for Lecanicillium lecanii and development of
           virulence‐enhanced strains against Aphis gossypii
    • Pages: 1951 - 1958
      Abstract: BACKGROUND Lecanicillium lecanii has been developed as a biopesticide and used in biological control of several agricultural insects. To improve fungal virulence, an optimised polyethylene glycol (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 optimised protoplast generation yielded 2.5 × 108 protoplasts g−1 wet mycelium of fungi, and gave nearly 98% viability and 80% regeneration on plates. Protease activities were increased about fivefold in transformants expressing CDEP1. The median lethal concentration (LC50) for transformants expressing CDEP1 was twofold 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 conidial germination as colony growth and conidial 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 conidial yields on insect cadavers, but insignificantly 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. © 2016 Society of Chemical Industry
      PubDate: 2016-02-19T05:09:36.502326-05:
      DOI: 10.1002/ps.4236
       
  • Volatiles released by Chinese liquorice roots mediate host location
           behaviour by neonate Porphyrophora sophorae (Hemiptera: Margarodidae)
    • Pages: 1959 - 1964
      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 analysed 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. © 2016 Society of Chemical Industry
      PubDate: 2016-02-26T04:36:33.782663-05:
      DOI: 10.1002/ps.4237
       
  • Mineralisation and degradation of 2,4‐dichlorophenoxyacetic acid
           dimethylamine salt in a biobed matrix and in topsoil
    • Authors: J Diane Knight; Allan J Cessna, Dean Ngombe, Tom M Wolfe
      Pages: 1965 - 1976
      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 mineralising and degrading 2,4‐dichlorophenoxyacetic acid dimethylamine salt (2,4‐D DMA) compared with the topsoil used in the biobed matrix. RESULTS Applying 2,4‐D DMA to the biobed matrix caused a 2–3 day 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 day incubation. When the herbicide was applied 5 times to the biobed matrix, net CO2 increased immediately after each 2,4‐D DMA application. Mineralisation of 2,4‐D DMA was 61.9% and residual 2,4‐D in the biobed matrix was 0.3% after 60 days, compared with corresponding values of 32.9 and 70.9% in topsoil. CONCLUSION The biobed matrix enhanced the mineralisation 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 mineralising and degrading the herbicide compared with 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 mineralisation. © 2016 Society of Chemical Industry
      PubDate: 2016-02-29T07:46:59.695954-05:
      DOI: 10.1002/ps.4238
       
  • Emergence of succinate dehydrogenase inhibitor resistance of Pyrenophora
           teres in Europe
    • Authors: Alexandra Rehfus; Simone Miessner, Janosch Achenbach, Dieter Strobel, Rosie Bryson, Gerd Stammler
      Pages: 1977 - 1988
      Abstract: BACKGROUND Net blotch caused by Pyrenophora teres is an important disease of barley worldwide. In addition to strobilurins (quinone ouside inhibitors) and azoles (demethylation inhibitors), 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 concerning 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 the succinate dehydrogenase enzyme. In 2013 and 2014, a significant increase in 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 microtitre 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 preventively. To date, most isolates with C‐G79R substitution have not simultaneously carried 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. © 2016 Society of Chemical Industry
      PubDate: 2016-03-03T06:27:30.465875-05:
      DOI: 10.1002/ps.4244
       
  • Modelling the current and potential future distributions of the sunn pest
           Eurygaster integriceps (Hemiptera: Scutelleridae) using CLIMEX
    • Authors: Rasha Aljaryian; Lalit Kumar, Subhashni Taylor
      Pages: 1989 - 2000
      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 polewards 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. © 2016 Society of Chemical Industry
      PubDate: 2016-03-04T03:46:36.304398-05:
      DOI: 10.1002/ps.4247
       
 
 
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