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Journal Cover Pest Management Science
  [SJR: 1.262]   [H-I: 72]   [4 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1526-498X - ISSN (Online) 1526-4998
   Published by John Wiley and Sons Homepage  [1598 journals]
  • 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 the African sweetpotato weevil Cylas puncticollis (Coleoptera:
           Brentidae)
    • 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
       
  • RNAi as a management tool for the western corn rootworm, Diabrotica
           virgifera virgifera
    • Abstract: The western corn rootworm (WCR), Diabrotica virgifera virgifera, is the most important pest of corn in the U.S. Corn Belt. Economic estimates indicate that costs of control and yield loss associated with WCR damage exceed $1 billion annually. Historically, corn rootworm management has been extremely difficult because of its ability to evolve resistance to both chemical insecticides and cultural control practices. Since 2003, the only novel commercialized developments in rootworm management have been transgenic plants expressing Bt insecticidal proteins. Four transgenic insecticidal proteins are currently registered for rootworm management, and field resistance to proteins from the Cry3 family highlights the importance of developing traits with new modes of action. One of the newest approaches for controlling rootworm pests involves RNA interference (RNAi). This review describes the current understanding of the RNAi mechanisms in WCR and the use of this technology for WCR management. Further, the review addresses the ecological risk assessment of RNAi and insect resistance management of RNAi for corn rootworm.
      PubDate: 2016-05-24T02:16:29.191577-05:
      DOI: 10.1002/ps.4324
       
  • 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
       
  • Structure, function and management of semi‐natural habitats for
           conservation biological control: A review of European studies
    • Abstract: Different semi‐natural habitats occur on farmland and it is the vegetation's traits and structure that subsequently determine their ability to support natural enemies and their associated contribution to conservation biocontrol. New habitats can be created and existing ones improved with agri‐environment scheme funding in all EU member states. Understanding the contribution of each habitat type can aid the development of conservation control strategies. Here we review the extent to which the predominant habitat types in Europe support natural enemies, whether this results in enhanced natural enemy densities in the adjacent crop, and whether this leads to reduced pest densities. Considerable variation exists in the available information for the different habitat types and trophic levels. Natural enemies within each habitat were the most studied, with less information on whether they were enhanced in adjacent fields, whilst their impact on pests was rarely investigated. Most information was available for woody and herbaceous linear habitats, yet not for woodland that can be the most common semi‐natural habitats in many regions. While the management and design of habitats offers potential to stimulate conservation biocontrol we also identified knowledge gaps. A better understanding of the relationship between resource availability and arthropod communities across habitat types, the spatio‐temporal distribution of resources in the landscape, and interactions with other factors that play a role in pest regulation could contribute to an informed management of semi‐natural habitats for biocontrol.
      PubDate: 2016-05-14T00:16:45.866127-05:
      DOI: 10.1002/ps.4318
       
  • The interactions between piperonyl butoxide and analogues with the
           metabolic enzymes FE4 and CYP6CY3 of the green peach aphid Myzus persicae
           (Hemiptera: Aphididae)
    • Authors: Michela Panini; Francesco Tozzi, Chris Bass, Christoph T. Zimmer, Linda Field, Valerio Borzatta, Emanuele Mazzoni, Graham Moores
      Abstract: BACKGROUND Piperonyl butoxide (PBO) is a well‐known insecticide synergist capable of interacting with phase 1 metabolic enzymes, specifically esterases and cytochrome P450s. In this study, structure activity relationship (SAR) analyses were used to characterise the interaction of around 30 analogues of PBO with the esterase FE4 and the P450 CYP6CY3 from insecticide resistant Myzus persicae (Sulzer), in order to predict the synthesis of more potent inhibitors. RESULTS Enzyme inhibition studies were performed against esterase and oxidase activities and together with in silico modelling, key activity determinants of the analogues were identified and optimised. Novel analogues were then designed and synthesised, some of which showed greater inhibition against both enzymatic systems: specifically, dihydrobenzofuran moieties containing an alkynyl side chain and a butyl side chain against FE4, and benzodioxole derivatives with a propyl/butyl side chain and an alkynyl ether moiety for CYP6CY3. CONCLUSIONS In vitro assays identified potential candidate synergists with high inhibitory potency. The in vivo confirmation of such results will allow consideration for a possible use in agriculture.
      PubDate: 2016-05-13T04:50:49.296776-05:
      DOI: 10.1002/ps.4314
       
  • The Importance of Regulatory Data Protection or Exclusive Use and other
           forms of Intellectual Property Rights in the Crop Protection Industry
    • Authors: Michael J. Carroll
      Abstract: BACKGROUND In order for a chemical plant protection product to be authorised for sale a registration dossier has to be assembled to demonstrate safety and efficacy to the satisfaction of government regulators. These studies and tests are protected for a period of 10 years in Europe, North America and some other jurisdictions from the date of first product authorisation so that only the data owner can gain commercial benefit from the data. RESULTS After first product authorisation the USA, Canada, Australia and Brazil give 10 years of data protection exclusive use for the safety and efficacy data necessary for the regulatory decision. At subsequent regulatory review financial compensation is payable to the data owner for new studies. The EU system offers sequential regulatory data protection exclusive use with compensation for vertebrate studies which can lead to confusion. CONCLUSION Data protection exclusive use is a time limited intellectual property right that gives the data owner a period of 10 years in Europe and North America whereby no other company can use the data for commercial gain. Subsequent regulatory reviews should not result in further periods of regulatory data protection exclusive use but compensation should be payable to the data generator.
      PubDate: 2016-05-13T04:50:45.944898-05:
      DOI: 10.1002/ps.4316
       
  • Not in my backyard: effectiveness of outdoor residual spraying from
           hand‐held sprayers against the mosquito Aedes albopictus in Rome,
           Italy
    • Abstract: BACKGROUND WHO guidelines state that adulticide interventions are recommended only in case of disease outbreak. However, peridomestic sprayings are carried out routinely to reduce Aedes albopictus (Skuse) nuisance, at least in Italy. Failing in keeping low adult abundance overtime triggers the need for further applications. The aim of the study was to investigate the effectiveness of a common control strategy routinely performed by citizens in highly infested urban sites inside the metropolitan city of Rome using a freely purchasable pyrethroid and a hand‐held sprayer. Moreover, the effectiveness evaluated in three field experiments was compared to the one achieved by blending the pyrethroid with a new carbon‐based liquid additive. RESULTS 86% post‐treatment reduction in Ae. albopictus abundance was observed in gravid and host‐seeking females, while the population recovery time was 10 days. Blending the insecticide with the additive lengthened mosquito recovery time over 14 days. CONCLUSION Peridomestic sprayings largely reduce mosquito population immediately after treatment but fail to keep low mosquito abundance on a longer period, partially explaining the uncontrolled repetitions of treatments. An optimal control application could benefit from research in the field of additive to improve the mosquito abatement and the overtime performances of pyrethroids.
      PubDate: 2016-05-13T04:50:43.673534-05:
      DOI: 10.1002/ps.4315
       
  • A generalised individual‐based algorithm for modelling the evolution
           of quantitative herbicide resistance in arable weed populations
    • Authors: Chun Liu; Melissa E. Bridges, Shiv S. Kaundun, Les Glasgow, Micheal D. K. Owen, Paul Neve
      Abstract: BACKGROUND Simulation models are useful tools for predicting and comparing the risk of herbicide resistance in weed populations under different management strategies. Most existing models assume a monogenic mechanism governing herbicide resistance evolution. However, growing evidence suggests that herbicide resistance is often inherited in a polygenic or quantitative fashion. Therefore, we constructed a generalised modelling framework to simulate the evolution of quantitative herbicide resistance in summer annual weeds. RESULTS Real‐field management parameters based on Amaranthus tuberculatus (Moq.) Sauer (syn. rudis) control with glyphosate and mesotrione in the Midwestern U.S. maize‐soybean agroecosystems demonstrated that the model can represent evolved herbicide resistance in realistic timescales. Sensitivity analyses showed that genetic and management parameters were impactful on the rate of quantitative herbicide resistance evolution, whilst biological parameters such as emergence and seed bank mortality were less important. CONCLUSION The simulation model provides a robust and widely applicable framework for predicting the evolution of quantitative herbicide resistance in summer annual weed populations. The sensitivity analyses identified weed characteristics that would favour herbicide resistance evolution, including high annual fecundity, large resistance phenotypic variance and pre‐existing herbicide resistance. Implications for herbicide resistance management and potential use of the model are discussed.
      PubDate: 2016-05-13T04:50:33.370933-05:
      DOI: 10.1002/ps.4317
       
  • Larval Western bean cutworm feeding damage encourages the development of
           Gibberella ear rot on field corn
    • Authors: Nicole S. Parker; Nolan R. Anderson, Douglas S. Richmond, Elizabeth Y. Long, Kiersten A. Wise, Christian H. Krupke
      Abstract: BACKGROUND A two year study was conducted to determine if western bean cutworm (Striacosta albicosta Smith) (WBC) larval feeding damage increases severity of the fungal disease Gibberella ear rot (Fusarium graminearum (Schwein.) Petch in field corn (Zea mays L.). The effect of a QoI fungicide, pyraclostrobin, on Gibberella ear rot severity and mycotoxin production, both with and without WBC pressure, was also evaluated. The impact of each variable was assessed individually and in combination to determine the effect of each upon ear disease severity. RESULTS There was a positive correlation between the presence of WBC larvae in field corn and Gibberella ear rot severity under inoculated conditions in two years of the experiment. An application of pyraclostrobin did not impact Gibberella ear rot development when applied at corn growth stage R1 (silks first emerging). CONCLUSION Feeding damage from WBC larvae significantly increases the development of F. graminearum in field corn. We conclude that an effective integrated management strategy for Gibberella ear rot should target the insect pest first, in an effort to limit disease severity and subsequent mycotoxin production by F. graminearum in kernels.
      PubDate: 2016-05-09T09:11:43.117516-05:
      DOI: 10.1002/ps.4313
       
  • Fitness costs and stability of Cry1Fa resistance in Brazilian populations
           of Spodoptera frugiperda
    • Abstract: BACKGROUND The presence of fitness costs of resistance to Bacillus thuringiensis (Bt) insecticidal proteins in insect populations may delay or even reverse the local evolution of insect resistance to Bt transgenic crops, deserving rigorous investigation. Here we assessed the fitness costs associated with Cry1Fa resistance in two fall armyworm strains [Spodoptera frugiperda (Lepidoptera: Noctuidae)] derived from field collections in different Brazilian regions and further selected in the laboratory for high levels of resistance to Cry1Fa using leaves of TC1507 corn. RESULTS Fitness components were compared using paired resistant and susceptible strains with similar genetic background and F1 generations from reciprocal crosses, all of them reared on non‐transgenic corn leaves. No apparent life‐history costs in the larval stage were observed in the Bt resistant strains. Moreover, the resistance remained stable for seven generations in the absence of selection with no decrease in the proportion of resistant individuals. Larval respiration rates were also similar between resistant and susceptible homozygotes, and heterozygotes displayed respiration rates and demographic performance equal or superior to that of susceptible homozygotes. CONCLUSION In combination, these results indicate lack of strong fitness costs associated with resistance to Cry1Fa in the fall armyworm strains studied. These findings suggest that Cry1Fa resistance in S. frugiperda populations is unlikely to be counter‐selected in Cry1Fa‐free environments.
      PubDate: 2016-05-05T02:05:35.437732-05:
      DOI: 10.1002/ps.4312
       
  • It Takes a Team: Reflections on Insecticide Discoveries, Toxicological
           Problems and Enjoying the Unexpected
    • Authors: Keith D. Wing
      Abstract: ADME (Absorbtion/Distribution/Metabolism/Excretion)–related studies are mandatory in agrochemical development/registration, but can also play a valuable role in the discovery process. In combination with target site potency, bioavailability/ADME characteristics determine agrochemical bioactivity and selectivity, and these concerns can dictate the fate of a discovery lead area. Bioavailability/ADME research was critical to the eventual commercialization of three different insecticide chemistries examined in this paper. In one situation, improved systemicity in anthranilic diamides was required to expand pest spectrum. In another, ADME tools were needed to improve the selective toxicity and nontarget safety of sodium channel blocker insecticides. Finally, differential ADME characteristics of two classes of hormone agonists dictated differential insecticidal activity, and were useful in optimizing the dibenzoylhydrazine ecdysone agonists. ADME discovery research will help companies to advance novel, efficacious and selective agrochemicals, but organizational patience and a desire to understand lead areas in depth are required.
      PubDate: 2016-05-05T02:05:27.994215-05:
      DOI: 10.1002/ps.4311
       
  • Laboratory studies of insecticide efficacy and resistance in Drosophila
           suzukii (Matsumura) (Diptera: Drosophilidae) populations from British
           Columbia, Canada
    • Abstract: BACKGROUND Drosophila suzukii (Matsumura), spotted wing drosophila (SWD), control can be improved with better knowledge of insecticide efficacy, timing of sprays, and rotations with registered products during the crop year. An efficacy bioassay was applied to study the dose–response of adult laboratory‐reared SWD collected from a cherry orchard in British Columbia (BC), Canada, to 11 insecticides. RESULTS Age and sex specific toxicities with the most effective insecticide, malathion, determined that older male SWD were significantly more susceptible than females. The selection for polygenic resistance to malathion using repeated exposure to sub‐lethal concentrations with both the original and an additional blueberry‐collected population of laboratory reared SWD determined no significant difference in susceptibility after 30 generations. CONCLUSION Possible reasons reported in Drosophila melanogaster studies where resistance did not occur after insecticide selection included avoidance and associated microbial complexes. The low level of malathion‐resistance observed in the selected SWD populations and a field‐collected population is useful information in the development of insecticide resistance management programs.
      PubDate: 2016-05-05T02:00:24.38099-05:0
      DOI: 10.1002/ps.4310
       
  • An artificial diet containing plant pollen for the mealybug predator
           Cryptolaemus montrouzieri
    • Authors: Jiaqin Xie; Hongsheng Wu, Hong Pang, Patrick De Clercq
      Abstract: BACKGROUND The specialist predatory ladybird Cryptolaemus montrouzieri is an effective natural enemy of mealybugs and plays a key role in the biological control of these pests. However, its mass production is complicated by the dependence on parallel cultures of mealybugs or the need for Ephestia kuehniella eggs as an expensive factitious prey. RESULTS Here we developed a pollen‐based artificial food for the predator to lower its dependence on natural prey. We found that this artificial diet was an effective alternative food for larvae and adults of this predator. The artificial food not only supported the development and reproduction of the predator in the first generation (F0) but also in the next generation (F1). Although the developmental time and preoviposition period of C. montrouzieri on the artificial food were ca. 1.5 days and 4 days longer than on the natural prey, the citrus mealybug Planococcus citri, respectively, its immature survival, fecundity and egg hatch were similar to that on mealybugs. In addition, adult C. montrouzieri maintained on natural or artificial food had a similar starvation resistance. CONCLUSIONS Our results suggest that the pollen‐based artificial diet can be used as an alternative food in the rearing of C. montrouzieri, and indicate its potential to support the mass production and wider application of this predator in biological control programs.
      PubDate: 2016-05-05T02:00:20.778774-05:
      DOI: 10.1002/ps.4309
       
  • A Retrospective Look at Anthranilic Diamide Insecticides: Discovery and
           Lead Optimization to Chlorantraniliprole and Cyantraniliprole
    • Authors: Thomas P. Selby; George P. Lahm, Thomas M. Stevenson
      Abstract: Anthranilic diamides are an important commercial synthetic class of insecticides (IRAC Group 28) that bind to the ryanodine receptor with selective potency against insect versus mammalian forms of the receptor. The first commercialized diamide, chlorantraniliprole, has exceptional activity against Lepidopteran pests. The second anthranilamide product, cyantraniliprole, has excellent cross‐spectrum activity against a range of insect orders, including both Lepidopteran and Hemipteran pests. Here, a retrospective look is presented on the discovery of the class along with chemistry highlights of the lead evolution to both products.
      PubDate: 2016-05-05T01:55:24.41971-05:0
      DOI: 10.1002/ps.4308
       
  • Proposal for a unified nomenclature for target site mutations associated
           with resistance to fungicides
    • Authors: W Mair; F Lopez Ruiz, G Stammler, W Clark, F Burnett, D Hollomon, H Ishii, T. S Thind, J.K. M Brown, B Fraaije, H Cools, M Shaw, S Fillinger, EM Terrado, G Schnabel, A. Mehl, RP Oliver
      Abstract: Evolved resistance to fungicides is a major problem limiting our ability to control agricultural, medical and veterinary pathogens and is frequently associated with substitutions in the amino acid sequence of the target protein. The convention for describing amino‐acid substitutions is to cite the wild type amino acid, the codon number and the new amino acid, using the one letter amino acid code. It has frequently been observed that orthologous amino acid mutations have been selected in different species by fungicides from the same mode of action class, but the amino acids have different numbers. These differences in numbering arise from the different lengths of the proteins in each species. The purpose of the current paper is to propose a system for unifying the labelling of amino acids in fungicide target proteins. To do this we have produced alignments between fungicide target proteins of relevant species fitted to a well‐studied “archetype” species. Orthologous amino acids in all species are then assigned numerical “labels” based on the position of the amino acid in the archetype protein.
      PubDate: 2016-05-04T04:41:32.801069-05:
      DOI: 10.1002/ps.4301
       
  • Novel and current rodenticides for pocket gopher Thomomys spp. management
           in vineyards: what works?
    • Authors: Roger A. Baldwin; Ryan Meinerz, Gary W. Witmer
      Abstract: Background Rodenticides are often included as part of an IPM approach for managing pocket gophers (Thomomys spp.) given that they are relatively quick and inexpensive to apply. Strychnine has historically been the most effective toxicant for pocket gophers, but its use is currently limited in the U.S.; alternative registered toxicants have not proven effective. Recent research with baits containing cholecalciferol plus anticoagulant toxicants proved effective against pocket gophers in a lab setting. Therefore, we established a field study to compare cholecalciferol plus anticoagulant combinations (0.03% cholecalciferol plus 0.005% diphacinone [C + D], 0.015% cholecalciferol plus 0.0025% brodifacoum [C+B1], 0.03% cholecalciferol plus 0.0025% brodifacoum [C+B2]) to strychnine (0.5%) for pocket gopher management. Results Strychnine treatments resulted in 100% efficacy after two treatment periods. Both C + D and C+B2 resulted in efficacy significantly greater than 70% after two treatment periods (83% and 75%, respectively). Efficacy from C+B1 (85%) was not significantly greater than 70%, but did yield high overall efficacy as well. Conclusion Although strychnine remains the most effective rodenticide for pocket gopher control, the cholecalciferol plus anticoagulant baits tested would be a good alternative when strychnine is unavailable. C + D may be the best option given that it uses a first‐generation anticoagulant as the synergist.
      PubDate: 2016-05-03T00:41:27.404309-05:
      DOI: 10.1002/ps.4307
       
  • Competition between the phytophagous stink bugs Euschistus heros and
           Piezodorus guildinii in soybeans
    • Abstract: BACKGROUND The abundance and contribution of the Neotropical brown stink bug, Euschistus heros (F.), and the redbanded stink bug, Piezodorus guildinii (West.), to the composition of insect pests of soybean, Glycine max (L.), fields have changed both spatially and temporally in Neotropical soybean production areas. Therefore, we assessed the competitiveness of each species in direct competition experiments following an additive series. We performed mixed (adult) insect infestations in soybean plants and evaluated the fitness of each species and the soybean yield. RESULTS While the competitive ability of E. heros was significantly compromised by increments in conspecifics and heterospecifics (i.e., P. guildinii), the competitive ability of P. guildinii was compromised by the presence of heterospecifics (i.e., E. heros). The reproductive output of P. guildinii remained unaffected by increments of E. heros or of P. guildinii. Intriguingly, despite the fact that P. guildinii apparently lost the competition with E. heros, almost no pod production was observed in any plant colonized by the former. CONCLUSIONS The higher abundance of E. heros on Neotropical soybean fields seems to result from higher competitive ability than its heterospecific competitor P. guildinii, which may prevent the higher losses caused by P. guildinii.
      PubDate: 2016-04-30T05:05:41.457121-05:
      DOI: 10.1002/ps.4306
       
  • ACIBENZOLAR‐S‐METHYL MAY PREVENT VECTOR‐MEDIATED
           FLAVESCENCE DORÉE PHYTOPLASMA TRANSMISSION, BUT IS INEFFECTIVE IN
           INDUCING RECOVERY OF INFECTED GRAPEVINES
    • Abstract: BACKGROUND Acibenzolar‐S‐methyl (BTH), a functional analog of Salicylic Acid (SA), is known to elicit a systemic resistance across a broad range of plant–pathogen interactions but, so far, it was not tested against Flavescence dorée (FDP), one of the most devastating grapevine diseases. Aims of this work were to evaluate the activity of BTH in preventing FDP transmission by the insect vector and in inducing recovery of infected grapevines. RESULTS Repeated applications of 2 mM BTH to test grapevine cuttings (cv Barbera) exposed to adults of the infectious vector, Scaphoideus titanus Ball, reduced the rate of infected plants. The effect was not recorded following similar BTH applications to highly susceptible young in vitro propagated vines. A high natural recovery rate (more than 70%) was observed over a three‐year‐period in field‐infected grapevines of the same cv. Under these conditions, BTH repeated applications over the whole period clearly failed to increase recovery of field‐infected grapevines. CONCLUSION Following a three‐year experiment, it can be concluded that, although high doses and repeated applications of BTH reduced vector transmission of FDP, BTH was ineffective in inducing recovery of FDP‐infected grapevines cv Barbera under field conditions.
      PubDate: 2016-04-27T01:31:09.45451-05:0
      DOI: 10.1002/ps.4303
       
  • Vkorc1‐sequencing suggests anticoagulant resistance in rats in New
           Zealand
    • Abstract: BACKGROUND Anticoagulant toxins are used globally to control rats. Resistance of Rattus species to these toxins now occurs in at least 18 countries in Europe, America, and Asia. Resistance is often associated with single nucleotide polymorphisms (SNP) in the Vkorc1 gene. This study gives a first overview of the distribution and frequency of Vkorc1 SNPs in rats in New Zealand. New Zealand is unusual in having no native rodents but three species of introduced Rattus – norvegicus Berk., rattus L. and exulans Peale. RESULTS Sequence variants occurred in at least one species of rat at all 30 of the sites sampled. Three new SNPs were identified, one in kiore and two in ship rats. No SNPs previously associated with resistance were found in Norway rats or kiore, but seven ship rats were heterozygous and one homozygous for the A74T variant. Its resultant Tyr25Phe mutation has previously been associated with resistance to both first and second generation anticoagulants in ship rats in Spain. CONCLUSIONS This is the first evidence of potential resistance to anticoagulant toxins in rats in New Zealand. Further testing using blood clotting response times in dosed rats is needed to confirm resistance potentially conferred by the Tyr25Phe mutation. Assessment is also needed of the potential of the other non‐synonymous variants (Ala14Val, Ala26Val) recorded in this study to confer resistance to anticoagulant toxins.
      PubDate: 2016-04-27T01:30:55.563106-05:
      DOI: 10.1002/ps.4304
       
  • Linking pollen quality and performance of Neoseiulus californicus (Acari:
           Phytoseiidae) in two‐spotted spider mite management programmes
    • Authors: Mostafa Khanamani; Yaghoub Fathipour, Ali Asghar Talebi, Mohammad Mehrabadi
      Abstract: BACKGROUND It has been shown that pollen as a dietary supplement may increase the establishment of generalist predatory mites, and therefore pest control by these mites can be provided. Life table studies were performed to evaluate the nutritional value of seven different pollens (almond, castor‐bean, date‐palm, maize, bitter‐orange, sunflower and mixed bee pollen) as a supplementary food source for the spider mite predator, Neoseiulus californicus McGregor. In addition, the nutritional quality of each pollen species was assessed through morphological and chemical analysis. RESULTS Preadult duration was longer when the predator fed on castor‐bean pollen (10.01 days) and bee pollen (9.94 days) compared with the others (5.58 ‐7.27 days). The cohort reared on almond pollen had the highest intrinsic rate of increase (r) (0.231 day−1), and those on mixed bee pollen had the lowest r (0.005 day−1). The levels of nutritional content (sugar, lipid and protein) were significantly different among tested pollens. CONCLUSIONS Comparison of N. californicus life table parameters on different diets revealed that the almond pollen (and after that the maize pollen) was a more suitable diet than the others. These findings will be useful to develop appropriate strategies for conservation of N. californicus to control the spider mites.
      PubDate: 2016-04-27T01:30:25.414719-05:
      DOI: 10.1002/ps.4305
       
  • Influence of Soil Properties and Soil Moisture on the Efficacy of
           Indaziflam and Flumioxazin on Kochia scoparia L.
    • Authors: Derek Sebastian; Scott Nissen, Phil Westra, Dale Shaner, Greg Butters
      Abstract: BACKGROUND Kochia (Kochia scoparia L.) is a highly competitive, non‐native weed found throughout the western US. Flumioxazin and indaziflam are two broad spectrum preemergence herbicides that can control kochia in a variety of crop and non‐crop situations; however, under dry conditions, these herbicides sometimes fail to control this important weed. There is very little information describing the effect of soil properties and soil moisture on the efficacy of these herbicides. RESULTS Soil organic matter (SOM) explained the highest proportion of variability in predicting the herbicide dose required for 80 percent kochia growth reduction (GR80) for flumioxazin and indaziflam (r2 = 0.72 and 0.79, respectively). SOM had a larger impact on flumioxazin phytotoxicity compared to indaziflam. Flumioxazin and indaziflam kochia phytotoxicity was greatly reduced at soil water potentials below −200 kPa. CONCLUSION Kochia can germinate at soil moisture potentials below the moisture required for flumioxazin and indaziflam activation, which means that kochia control is greatly influenced by the complex interaction between soil physical properties and soil moisture. This research can be used to better understand how and why some weeds, like kochia, are so difficult to manage even with herbicides that normally provide excellent control.
      PubDate: 2016-04-25T00:30:36.611993-05:
      DOI: 10.1002/ps.4300
       
  • Dust drift reduction effect of an air conveyor kit (dual pipe deflector)
           mounted on different maize pneumatic drills
    • Authors: Marco Manzone; Paolo Balsari, Paolo Marucco, Mario Tamagnone
      Abstract: BACKGROUND All maize drills produce a fine dust due to the abrasions of the seed coating that occur inside the seeding element. Nevertheless, the air stream generated by the fan of pneumatic drills – necessary to create a depression in the sowing element of the machine and to guarantee a correct seeds deposition – can blow away the solid particles detached from the seeds. In order to reduce this phenomena, coated maize seeds company (Syngenta®) has set up an ad hoc kit “dual pipe deflector” that easy a fits different pneumatic drills (also old drills). In this study, the efficiency of this kit and the influence of different drills types on the kit effects in reducing the environmental contamination, were evaluated using three different pneumatic seed drills models. RESULTS The research showed that dual pipe deflector installed on the drill in standard configuration did not change the seeder performance and using this kit on pneumatic drills, independent of their design, it is possible to reduce up to 69% the amount of dust drift with respect to the conventional machine set up. CONCLUSION Dual pipe deflector, under conditions explained in this experimentation, showed good performances with all types of maize pneumatic drills used. Independent of the seeder model on which is mounted, it is able to obtain similar results highlighting an high operative versatility.
      PubDate: 2016-04-25T00:30:31.180102-05:
      DOI: 10.1002/ps.4302
       
  • Phytotoxicity of aminobisphosphonates targeting both
           δ1‐pyrroline‐5‐carboxylate reductase and glutamine
           synthetase
    • Abstract: BACKGROUND Dual‐target inhibitors may contribute to the management of herbicide‐resistant weeds and avoid or delay the selection of resistant biotypes. Some aminobisphosphonates inhibit the activity of both glutamine synthetase and δ1‐pyrroline‐5‐carboxylate (P5C) reductase in vitro, but the relevance of the latter in vivo has not been proven, yet. This study aimed at demonstrating that these compounds can block also proline synthesis in planta. RESULTS Two aminophosphonates, namely 3,5‐dichlorophenylamino‐methylenebisphosphonic acid and 3,5‐dibromophenylaminomethylenebis‐phosphonic acid (Br2PAMBPA), showed inverse effectiveness against the two partially purified target enzymes from rapeseed. The compounds showed equipotency in inhibiting the growth of rapeseed seedlings and cultured cells. The analysis of amino acid content in treated cells showed a strong reduction of glutamate and glutamate‐related amino acid pools, but a milder effect on free proline. In the case of Br2PAMBPA, toxic P5C levels accumulated in treated seedlings, proving that the inhibition of P5C reductase takes place in situ. CONCLUSIONS Phenyl‐substituted aminobisphosphonates may be regarded as true dual‐target inhibitors. Their use to develop new active principles for crop protection could consequently represent a tool to address the problem of target‐site resistance among weeds.
      PubDate: 2016-04-22T03:55:22.756387-05:
      DOI: 10.1002/ps.4299
       
  • Impact of Atrazine Prohibition on the Sustainability of Weed Management in
           Wisconsin Maize Production
    • Authors: Fengxia Dong; Paul D. Mitchell, Vince M. Davis, Ross Recker
      Abstract: BACKGROUND Controversy has surrounded atrazine due to its susceptibility to leaching and runoff, with regular calls for a ban or restrictions on its use. In the context of a decreasing trend in the percentage of US maize using no‐till since 2008, coinciding with the trend of glyphosate‐resistant weeds becoming problematic in the Midwestern US, we empirically examine how atrazine use restrictions impacted the diversity of weed management practices used by Wisconsin maize farmers. RESULTS Using survey data from farms inside and outside atrazine prohibition areas, we found that prohibiting atrazine did not directly impact tillage practices, but rather it increased adoption of herbicide‐resistant seed, which then increased adoption of conservation tillage systems. We also found that prohibiting atrazine and using herbicide‐resistant seed decreased the number of herbicide sites of action used. CONCLUSIONS The results indicate that prohibiting atrazine reduced the diversity of weed management practices, which increased the risk of herbicide resistance. Our concern is that a regulatory policy to address one issue (atrazine in groundwater) has induced farmer responses that increase problems with another issue (herbicide‐resistant weeds) that longer term will contribute to water quality problems from increased soil erosion and offset the initial benefits.
      PubDate: 2016-04-21T07:25:44.051588-05:
      DOI: 10.1002/ps.4298
       
  • The efficacy of Beauveria bassiana, jasmonic acid and chlorantraniliprole
           
    • Authors: Aneela Younas; Zaeema Khan, Waqas Wakil, Muhammad Shaaban, Sean Michael Prager
      Abstract: BCKGROUND A robust integrated pest management (IPM) program is needed to reduce the use of insecticides in controlling Helicoverpa armigera. Therefore, a two year field study was conducted to evaluate the use of alternative control measures (biochemical use) for H. armigera relative to exclusively use of chemical insecticides. The entomopathogenic fungi Beauveria bassiana, jasmonic acid and the insecticide chlorantraniliprole were each applied twice during the chickpea‐growing season. RESULTS All three applied materials (either alone or combined) significantly (p ≤ 0.05) reduced the larval population of H. armigera and pod infestation. Effects increased with time and the maximum difference was observed 7 days after the second application in each year. The lowest numbers of larvae per plant and pod infestation were in the B. bassiana 3.21 × 106 + chlorantraniliprole treatment in both 2009/2010 and 2010/2011 year. The reduction in the larval population and pod infestation increased chickpea yield and the highest yield in both seasons, and the maximum yield was obtained in the B. bassiana 3.21 × 106 + chlorantraniliprole treatment. The populations of natural enemies were highest in the jasmonic acid treatment. CONCLUSION The results suggest that B. bassiana, jasmonic acid and chlorantraniliprole may be useful components for H. armigera IPM strategy.
      PubDate: 2016-04-21T07:20:20.954756-05:
      DOI: 10.1002/ps.4297
       
  • Methoxyfenozide resistance of house fly, Musca domestica L. (Diptera:
           Muscidae): Cross‐resistance patterns, stability and associated
           fitness costs
    • Authors: Rizwan Mustafa Shah; Sarfraz Ali Shad, Naeem Abbas
      Abstract: BACKGROUND House fly, Musca domestica L., (Diptera: Muscidae) is an insect pest of public health and veterinary importance with ability to develop resistance to insecticides. Methoxyfenozide, an ecdysone agonist, is a bio‐rational insecticide being used for the management of various insect pests, including house flies. To design an effective resistance management strategy, life history traits based on laboratory observations were established for methoxyfenozide resistant (MXY‐SEL), unselected counterpart (UNSEL) and reciprocal cross strains of house fly. RESULTS The MXY‐SEL developed a resistance ratio of 160.99 after 30 generations of selection with methoxyfenozide compared to the UNSEL. The MXY‐SEL showed very low cross‐resistance to cyromazine, fipronil and chlorpyrifos and no cross‐resistance to spinosad and bifenthrin, when compared to the Methoxy‐Field population. Resistance to methoxyfenozide, cyromazine, fipronil, spinosad, chlorpyrifos, and bifenthrin was unstable in the MXY‐SEL. The MXY‐SEL had a reduced relative fitness (0.31), with lower hatchability, lower number of next generation larvae, lower intrinsic rate of natural increase, and lower biotic potential compared to the UNSEL. CONCLUSIONS Disadvantageous life history traits of the MXY‐SEL suggest that development of resistance to methoxyfenozide has considerable costs of fitness for this strain. Moreover, the unstable resistance to tested chemicals provides useful information to preserve the efficacy of these chemicals.
      PubDate: 2016-04-21T06:55:26.078672-05:
      DOI: 10.1002/ps.4296
       
  • Diet quality affects bait performance in German cockroaches (Dictyoptera:
           Blattellidae)
    • Authors: Alexander E. Ko; Coby Schal, Jules Silverman
      Abstract: BACKGROUND Bait formulations are widely used to control German cockroach (Blattella germanica) populations. To perform optimally, these formulations must compete favorably with non‐toxic alternative foods present within the insect's habitat. We hypothesized that the nutritional history of cockroaches and their acceptance or avoidance of glucose would affect their food preference and thus bait efficacy. To test this hypothesis, we conducted a controlled laboratory experiment, first providing glucose‐accepting and glucose‐averse cockroaches nutritionally defined diets and then offering them identical diets containing the insecticide hydramethylnon as a bait proxy to evaluate the effect of diets of differing macronutrient composition on bait performance. RESULTS The interaction between diet composition and bait composition affected the survival of adult males as well as first instar nymphs exposed to excretions produced by these males. Survival analyses indicated different responses of glucose‐averse and glucose‐accepting insects, but generally, any combination of diet and bait that resulted in high diet intake and low bait intake decreased secondary kill. CONCLUSIONS This study represents a comprehensive examination of the effect of alternative foods on bait efficacy. We suggest that disparities between the nutritional quality of baits and the foods that are naturally available could profoundly impact the management of German cockroach infestations.
      PubDate: 2016-04-21T06:55:22.858708-05:
      DOI: 10.1002/ps.4295
       
  • The influence of time and distance traveled by bed bugs, Cimex
           lectularius, on permethrin uptake from treated mattress liners
    • Authors: Stephen A. Kells; Sabrina N. Hymel
      Abstract: Background Residual insecticides interrupt dispersal of bed bugs (Cimex lectularius, L.), but one of the issues encountered with residual applications is understanding the uptake of active residues by the insect. This study determined permethrin uptake by bed bugs walking on the ActiveGuard® Mattress Liner product, via a combination of video‐recording in arenas and gas chromatography analyses. Results The best model for estimating permethrin uptake utilized a covariance model (r2 = 0.469) with two factors: time of exposure (F1,55 = 2.44, P < 0.001) and distance traveled (F1,55 = 0.30 P = 0.0460). Bed bug permethrin‐uptake was 15.1 (95 % CI: 10.3 – 22.1) ng insect−1 within 1 min exposure; 21.0 (15.0, 31.0) ng insect−1 in 10 min; and, ≈42 (29.8, 60.6) ng insect−1 in ≥ 50 min exposure. Correcting for % recovery, these values would be would be increased by a factor of 1.21. Conclusion This permethrin‐treated fabric provides a surface from which bed bugs begin to rapidly absorb permethrin on contact and within the first 1 cm of travel. Variability in uptake was likely a result of grooming and thigmotaxis, and future work should use quantitative methods to study behaviors and formulations that increase exposure to the toxicant.
      PubDate: 2016-04-21T06:50:22.403982-05:
      DOI: 10.1002/ps.4294
       
  • Non‐target‐site glyphosate resistance in Conyza bonariensis is
           based on modified subcellular distribution of the herbicide
    • Authors: Ziv Kleinman; Baruch Rubin
      Abstract: BACKGROUND Conyza spp. was the first broadleaf weed reported to have evolved glyphosate resistance. Several mechanisms have been proposed for glyphosate resistance. In an effort to elucidate the mechanism of this resistance in Conyza bonariensis, possible target‐site and non‐target site mechanisms were investigated in glyphosate‐resistant (GR) C. bonariensis biotypes. RESULTS Using differential glyphosate applications and analyses of shikimate accumulation, we followed the herbicide effect in different plant organs and monitored the herbicide's apparent mobility. We found high shikimate levels in the roots and young leaves of GS plants regardless of the site of application; whereas in GR plants, shikimate accumulated mainly in treated young leaves. 14C‐glyphosate studies, however, revealed the expected source‐to‐sink translocation pattern in both GS and GR plants. Sequencing of the appropriate EPSPS DNA fragments of GR and glyphosate‐sensitive (GS) plants revealed no alteration at the Pro106 position. CONCLUSION These data support the hypothesis that the glyphosate resistance of our Conyza bonariensis GR biotypes is associated with altered subcellular distribution of glyphosate, which keeps the herbicide sequestered away from the EPSPS target site in the chloroplast.
      PubDate: 2016-04-21T06:45:23.281578-05:
      DOI: 10.1002/ps.4293
       
  • Landscape crop composition effects on cotton yield, Lygus hesperus
           densities, and pesticide use
    • Authors: Matthew H. Meisner; Tania Zaviezo, Jay A. Rosenheim
      Abstract: BACKGROUND Landscape crop composition surrounding agricultural fields is known to affect the density of crop pests, but quantifying these effects, as well as measuring how they translate to changes in yield, is difficult. Using a large dataset consisting of 1498 records of commercial cotton production in California between 1997 and 2008, we explored the relationship between landscape composition and cotton yield, the density of Lygus hesperus (a key cotton pest) at field‐level and within‐field spatial scales, and pesticide use. RESULTS We found that the crop composition immediately adjacent to a cotton field was associated with substantial differences in cotton yield, L. hesperus density, and pesticide use. Furthermore, crops that tended to be associated with increased L. hesperus density also tended to be associated with increased pesticide use and decreased cotton yield. CONCLUSION Our results suggest a possible mechanism by which landscape composition can affect cotton yield: by increasing the density of pests that in turn damage cotton plants. Our quantification of how surrounding crops affect pest densities, and in turn yield, in cotton fields, has significant impacts for cotton farmers who can use this information to help optimize crop selection and ranch layout.
      PubDate: 2016-04-10T22:35:23.986891-05:
      DOI: 10.1002/ps.4290
       
  • Effect of three safeners on sulfur assimilation and iron deficiency
           response in barley (Hordeum vulgare) plants
    • Authors: Maria Luce Bartucca; Silvia Celletti, Stefania Astolfi, Tanja Mimmo, Stefano Cesco, Ivan Panfili, Daniele Del Buono
      Abstract: BACKGROUND Safeners are agrochemicals used in agriculture to protect crop from herbicide injuries. They act by stimulating herbicide metabolism. Since graminaceous plants to cope with iron (Fe) deficiency activate sulfur (S) metabolism and release huge amounts of Fe chelating compounds (phytosiderophores – PSs), we investigated in barley plants (Hordeum vulgare, L.) grown in Fe‐deficiency the effects of three safeners on two enzymes of S assimilation, cysteine (Cys) and glutathione (GSH) contents, and PSs release. Finally, we monitored the root Fe content in plants treated with the most effective safener. RESULTS Generally, all the safeners activated S metabolism and increased Cys and GSH contents. In addition, the safened plants excreted higher levels of PSs. Being mefenpyr‐diethyl (Mef) the most effective in causing these effects, we assessed Fe concentration in Mef treated barley and we found higher Fe levels than those of untreated plants. CONCLUSION The three safeners differently, but specifically, activated S reductive metabolism, regulated Cys and GSH contents, PSs rate release and Fe content (Mef treated barley). The results of this research provide new indications on the biochemical and physiological mechanisms involved in the safening action.
      PubDate: 2016-04-08T13:09:21.844325-05:
      DOI: 10.1002/ps.4291
       
  • Postharvest impacts of rodents in Myanmar; how much rice do they eat and
           damage?
    • Authors: Nyo Me Htwe; Grant R Singleton, Pyai Phyo Maw
      Abstract: BACKGROUND We undertook studies on postharvest losses by rodents in two townships in the Ayeyarwady delta, Myanmar. Farmers harvest their monsoon rice crop and then stack it on levee banks to await threshing 4–6 weeks later. After threshing and drying, paddy rice is stored in granaries. The amount of grain stored in burrows was collected 4 weeks after harvest by excavating burrows. In grain stores, we quantified weight of grain consumed by rodents for 3–6 months postharvest. RESULTS The dominant species in the field were Bandicota bengalensis and B. indica, whereas in grain stores the dominant species were Rattus rattus and R. exulans. The mean grain stored by rodents in burrows was 1.49 ± 0.9 kg/ burrow in 2013 and 1.41 ± 0.7 kg/ burrow in 2014. The mean loss of grain in granaries was higher in Daik U (14% in 2013, 4% in 2014) than Maubin (8.2% in 2013, 1.2% in 2014). The total amount of grain lost to rodents during piling and storing could feed households from 1.6‐4 months. CONCLUSION Postharvest losses to grain is a significant food security issue for smallholder farmers in Myanmar. Community rodent management and better rodent proofing of granaries are recommended to reduce rodent losses.
      PubDate: 2016-04-08T13:08:28.601908-05:
      DOI: 10.1002/ps.4292
       
  • Lures for Red Palm Weevil trapping systems: aggregation pheromone and
           synthetic kairomone
    • Abstract: BACKGROUND The optimization of the lure is essential for the implementation of trapping systems to control insect pests. In this work, the response of the red palm weevil (RPW), Rhynchophorus ferrugineus Olivier, to increasing emission rates of its aggregation pheromone (ferrugineol) and the efficacy of a convenient synthetic kairomone based on fermentation odors (ethyl acetate and ethanol) have been evaluated in different years and locations along the Mediterranean basin. RESULTS In general, although capture data and emission had noticeable variability among locations, significantly less RPW were captured in pyramidal Picusan® traps with the lowest ferrugineol emission rates tested (0.6‐3.8 mg/day−1). Captures increase rapidly with ferrugineol emission up to 4–5 mg day−1; then, higher emission rates did not improve nor decrease captures, up to the highest emission rate tested of 50.9 mg day−1. Thus, there is no evidence of an optimum release rate corresponding with a maximum of RPW catches. Traps baited with the synthetic kairomone (1:3 ethyl acetate/ethanol) captured from 1.4 to 2.2 times more total weevils than traps baited only with ferrugineol. Moreover, in most of the locations, the synthetic blend was at least as effective as the local co‐attractants used (plant material + molasses). CONCLUSIONS Ferrugineol emission rate can vary in a wide range without affecting significantly RPW response. Co‐attractants based on fermenting compounds, ethyl acetate and ethanol, are able to improve the attractant level of ferrugineol and could be employed to replace non‐standardized natural kairomones in RPW trapping systems after further optimization of their proportions and doses.
      PubDate: 2016-04-06T03:19:10.334186-05:
      DOI: 10.1002/ps.4289
       
  • Two compounds in bed bug feces are sufficient to elicit off‐host
           aggregation by bed bugs, Cimex lectularius
    • Authors: Joelle F. Olson; Leonard M. Ver Vers, Roger D. Moon, Stephen A. Kells
      Abstract: BACKGROUND After feeding, bed bugs aggregate in cracks and crevices near a host. Aggregation and arrestment are mediated by tactile and chemical stimuli associated with the bugs’ feces and exuviae. Volatiles derived from fecally stained filter papers were analyzed by SPME and evaluated using a multi‐choice behavioral assay to determine their impact on bed bug aggregation. In addition, crude fecal extracts were collected in methanol, analyzed by GC‐EAD and GC‐MS and evaluated in open‐air multiple choice behavioral assays. RESULTS An SPME method was used to detect (E)‐2‐hexenal and (E)‐2‐octenal in heated bed bug feces. The presence of these two volatile components did not affect aggregation. Analysis of the crude fecal extracts revealed several semi‐volatile nitrogenous compounds, a carboxylic acid, and a sulfur based compound. Adult antennae responded to compounds eluted from three regions of the crude extract using GC‐EAD. A combination of two compounds, dimethyl trisulfide (DMTS) and methyldiethanolamine (MDEA) resulted in aggregation responses equivalent to original crude extract. CONCLUSION Bed bug aggregation is mediated by semi‐volatile compounds derived from fecal extracts, and two compounds are sufficient to elicit aggregation. The two compounds identified here could be used to enhance the effectiveness of insecticidal applications or improve monitoring techniques.
      PubDate: 2016-04-06T02:52:55.892661-05:
      DOI: 10.1002/ps.4286
       
  • Knockdown of two trehalose‐6‐phosphate synthases severely
           affects chitin metabolism gene expression in the brown planthopper
           Nilaparvata lugens
    • Abstract: BACKGROUND RNA interference combined with digital gene expression (DGE) analysis can be used to study gene function. Trehalose‐6‐phosphate synthase (TPS) plays a key role in the synthesis of trehalose and insect development. RESULTS The DGE analysis revealed that the expression of 9 or 4 chitinase genes was decreased significantly 48 h after NLTPS1 and NLTPS2 knockdown by RNAi, respectively. Additionally, abnormal phenotypes were noted, and approximately 30% of insects died. HK and G6PI2 expression decreased significantly 72 h, whereas GFAT, GNPNA, and UAP expression increased significantly 72 h after two NLTPS genes RNAi knockdown. PGM1 expression decreased significantly after TPS2 knockdown, whereas PGM2 expression increased significantly and the expression of three CHS genes decreased 48 h after TPS1 knockdown. The mRNA expression of all of twelve chitin degradation genes decreased 48 h after NLTPS1 and NLTPS2 RNAi treatment, and Cht2, Cht3, Cht6, Cht7, Cht10, and ENGase levels remained significantly decreased up to 72 h after NLTPS1 and NLTPS2 RNAi knockdown. CONCLUSIONS These results demonstrate that silencing of TPS genes can lead to increased molting deformities and mortality rates due to the misregulation of genes involved in chitin metabolism, and TPS genes are potential pest control targets in the future.
      PubDate: 2016-04-06T02:51:47.088151-05:
      DOI: 10.1002/ps.4287
       
  • Evaluation of chromatic cue for trapping Bactrocera tau
    • Authors: Lei Li; Huabo Ma, Liming Niu, Dongyin Han, Fangping Zhang, Junyu Chen, Yueguan Fu
      Abstract: BACKGROUND Trapping technology based on chromatic cues is an important strategy in controlling Tephritidae (fruit flies). The objectives of this present study were to evaluate the preference of Bactrocera tau to different chromatic cues and to explore an easy method to print and reproduce color paper. RESULTS Chromatic cues significantly affected the preference of adult B. tau. The wavelengths in the range of 515 to 604 nm were the suitable wavelengths for trapping B. tau. Different day‐old B. tau had different color preferences. Virtual wavelengths of 595 (yellow) and 568 nm (yellowish green) were the optimum wavelengths for trapping 5‐day‐old to 7‐day‐old B. tau and 30‐day‐old to 32‐day‐old B. tau, respectively. The trap type and height significantly influenced the attraction efficiency of B. tau. The number of B. tau on color traps hung perpendicular to plant rows were not significantly higher than those hung parallel to plant rows. CONCLUSION The quantization of color on the basis of Bruton's wavelength to RGB function can be served as an alternative method to print and reproduce the color papers, but a corrected equation should be established between the theoretical wavelength and actual wavelength of color papers. Results show that a compound paper colored yellow (595 nm) and yellowish green (568 nm) installed at 60 and 90 cm in height above the ground show the maximum effect for trapping B. tau.
      PubDate: 2016-04-06T02:49:50.114541-05:
      DOI: 10.1002/ps.4288
       
  • Trypsin inhibitor from Leucaena leucocephala seeds delays and disrupts the
           development of Aedes aegypti, a multiple disease vector
    • Abstract: BACKGROUND Nowadays Aedes aegypti mosquito represents a serious issue in public health due to the large outbreaks of the arboviral diseases Zika, Dengue, Chikungunya and Yellow fever. This holometabolous insect has midgut digestive enzymes which are trypsin and chymotrypsin‐like proteins. Protease inhibitors are able to bind to proteolytic enzymes and promote a blockage in digestion and nutrition leading to death. Thus, we investigated the effect of trypsin inhibitor of Leucaena leucocephala (LTI) seeds upon egg hatching, larval development and digestive midgut proteases. RESULTS LTI was obtained by TCA‐precipitation followed by a single chromatography step on anhydrous trypsin sepharose. SDS‐PAGE showed a single protein band with molecular mass near 20 kDa. After exposure of Ae. aegypti egg to LTI (0.3 mg.mL−1), egg hatching was reduced (50%). LTI did not show acute toxicity on newly hatched larvae incubated under the same conditions, but after ten days of exposure a high mortality rate (86%) was observed and the surviving larvae had a 25% delay in development. LTI was able to inhibit in vitro the midgut enzymatic activity (70%) and when larvae were incubated with LTI solution we observed an inhibition of 56%. CONCLUSIONS LTI is a promising new tool to control critical points of Ae. aegypti development.
      PubDate: 2016-04-04T06:29:03.104057-05:
      DOI: 10.1002/ps.4284
       
  • The mononuclear NiII complex
           bis(azido‐κN)bis[2,5‐bis(pyridin‐2‐yl)‐1,3,4‐thiadiazole‐κ2N2,N3]nickel(II)
           protects tomato from Verticillium dahliae by inhibiting the fungal growth
           and activating plant defenses
    • Authors: Hanane Zine; Lalla Aicha Rifai, Tayeb Koussa, Fouad Bentiss, Salaheddine Guesmi, Abdelhakim Laachir, Kacem Makroum, Malika Belfaiza, Mohamed Faize
      Abstract: BACKGROUND The antifungal proprieties of the nickel complex bis(azido‐κN)bis[2,5‐bis(pyridin‐2‐yl)‐1,3,4‐thiadiazole‐κ2N2,N3]nickel(II) (noted NiL2(N3)2) and its parental ligand 2,5‐bis(pyridin‐2‐yl)‐1,3,4‐thiadiazole (L) were examined to evaluate their ability to protect tomato plants against Verticillium dahliae. Our main objectives were to determine their effects on the in vitro growth of the pathogen, and their aptitude on controlling verticillium wilt and activating plant defense responses in the greenhouse. RESULTS NiL2(N3)2 exhibited in vitro an elevated inhibition of radial growth of three strains of the pathogen. According to the strain, the EC50 values ranged from 10 to 29 µg ml−1 for NiL2(N3)2. In the greenhouse, it induced an elevated protection against V. dahliae when it was applied twice as foliar sprays at 50 µg ml−1. It reduced leaf alteration index by 85% and vessel browning by 96%. In addition, its protective ability was associated with the accumulation of H2O2, and the activation of total phenolic content as well as potentiation of the activity of peroxidase and polyphenol oxidase. CONCLUSION These results demonstrated that coordination of ligand with Ni associated to the azide as a co‐ligand resulted in the improvement of its biological activity by both inhibiting the growth of the V. dahliae and activating plant defense responses.
      PubDate: 2016-04-04T06:27:38.017174-05:
      DOI: 10.1002/ps.4285
       
  • Impact of Bacillus cereus NRKT on grape ripe rot disease through
           resveratrol synthesis in berry skin
    • Authors: Takanori Aoki; Yoshinao Aoki, Shiho Ishiai, Misa Otoguro, Shunji Suzuki
      Abstract: BACKGROUND Vine growers are faced with the difficult problem of how to control grape ripe rot disease in vineyards because of fear of accumulation of pesticide residues on grape berries near harvest. Biological control is an alternative non‐hazardous technique to control the diseases. RESULTS Application of resveratrol‐synthesis‐promoting bacterium, Bacillus cereus strain NRKT, decreased the incidence of grape ripe rot disease caused by Colletotrichum gloeosporioides in a vineyard. The application of NRKT to berry bunches upregulated the gene expression of stilbene synthase, a key enzyme for resveratrol synthesis in berry skins, thereby promoting resveratrol synthesis in berry skins. CONCLUSION The potential use of NRKT in vineyards is expected to contribute to the increase of resveratrol content in berry skins, thereby protecting grape berries against fungal diseases.
      PubDate: 2016-04-01T00:12:10.405601-05:
      DOI: 10.1002/ps.4283
       
  • Migration by seed dispersal of ACCase inhibitor resistant Avena fatua in
           Northwestern Mexico
    • Abstract: BACKGROUND Biotypes of Avena fatua resistant to ACCase‐inhibiting herbicides have been reported in the States of Baja California (BC) and Sonora (SON), Mexico. We hypothesized that resistant biotypes present in SON (Valle de Hermosillo and Valle del Yaqui) are derived from a resistant population from BC (Valle de Mexicali) via gene flow, due to the transport and exchange of contaminated wheat seed. This study aimed to determine: 1) the resistance of A. fatua to ACCase‐inhibiting herbicides in populations from BC and SON, 2) the mutation at the site of action and 3) the genetic structure and gene flow among populations. RESULTS DNA sequencing showed that all biotypes shared the same mutation (Leu x Ile at codon 1781). Microsatellites showed evidence of a genetic bottleneck in SON, and spatial analysis of molecular variance grouped one biotype from the Valle de Mexicali with two biotypes from the Valle de Hermosillo. Migration analysis suggested gene flow from the Valle de Mexicali to the Valle de Hermosillo, but not to the Valle del Yaqui. CONCLUSIONS The presence of resistant biotypes of Avena fatua in the Valle de Hermosillo, SON are likely derived from seeds from BC, possibly through the transport of contaminated wheat seeds.
      PubDate: 2016-04-01T00:11:55.39262-05:0
      DOI: 10.1002/ps.4282
       
  • Distinguishing between weedy Amaranthus species based on intron one
           sequences from the 5‐enolpyruvylshikimate‐3‐phosphate
           synthase (EPSPS) gene
    • Authors: Alice A. Wright; William T. Molin, Vijay K. Nandula
      Abstract: BACKGROUND Hybridization between Amaranthus species and the potential for herbicide resistance to be transferred by hybridization are of growing concern in the weed science community. Early detection of evolved herbicide resistance and hybrids expressing resistance to single or multiple herbicides is important to develop an effective control strategy. RESULTS A PCR test was developed to quickly identify weedy amaranths and any hybrids. The sequences of intron one for the 5‐enolpyruvylshikimate‐3‐phosphate synthase (EPSPS; EC 2.5.1.19) gene were determined for Amaranthus palmeri, A. retroflexus, A. blitoides, A. viridis, A. tuberculatus, and A. hybridus. These sequences were aligned and primers were developed in areas where the sequence differed between species. Species specific primers and cycle conditions were successfully developed. These primers produce a single robust band only for the species for which they were designed. CONCLUSION The PCR techniques described here allow identification of a weedy amaranth or suspect hybrid in a few hours. Using a similar target, it may be possible to design similar, simple PCR tests to identify even more difficult to distinguish weed species or weeds prone to interspecific hybridization.
      PubDate: 2016-03-23T01:30:50.477582-05:
      DOI: 10.1002/ps.4280
       
  • Evaluation of Spray Application Methods for Navel Orangeworm Control in
           Almonds
    • Authors: James C. Markle; Franz J. Niederholzer, Frank G. Zalom
      Abstract: BACKGROUND Gear Up, Throttle Down (GUTD) and Inward Only strategies represent potential alternatives to conventional airblast applications to reduce spray drift. This study evaluates Inward Only and a modified version of GUTD in almonds, the largest U.S. tree crop, at the recommended hull split treatment timing for control of navel orangeworm (NOW), the key almond insect pest. RESULTS Conventional treatment produced the most drift (15.6% of total bifenthrin load) while the GUTD and Inward Only treatments produced only 7.6% and 9.7%, respectively. For all methods 92‐94% of the drift was found in the first 15.2 m downwind of the orchard. NOW control was lower for the Inward Only treatment compared with the GUTD and Conventional treatments. NOW control was consistently lower at the 4.88 m height relative to 2.44 m in all treatments, reflecting the reduced deposition higher in the tree canopy recorded in deposition samples. CONCLUSION While Inward Only treatments reduced spray drift relative to the Conventional application method, poorer control of NOW, the key insect pest of almonds, in the Inward Only treatment would likely limit its voluntary use by growers. However, GUTD holds promise for use at the hull split treatment timing to address spray drift.
      PubDate: 2016-03-22T03:50:23.073853-05:
      DOI: 10.1002/ps.4279
       
  • Accurate prediction of black‐rot epidemics in vineyards using a
           weather‐driven disease model
    • Abstract: Background Grapevine black‐rot caused by Guignardia bidwellii is a serious threat in vineyards, especially in areas with cool and humid springs. A mechanistic, weather‐driven model was recently developed for the detailed prediction of black‐rot epidemics. The aim of this work was the evaluation of the model by comparison with observed disease development in leaves and clusters in a vineyard in north Italy from 2013 to 2015. Results The model accurately predicted disease onset. The probability of predicting new infections that did not occur (i.e., unjustified alarms) was ≤ 0.180, while the probability of missing actual infections was 0.175 for leaves and 0.263 for clusters. In 78% of these false negative predictions, the difference between expected and actual disease onset was ± 2 days; therefore, only one infection period was actually missed by the model. The model slightly overestimated disease severity (mainly on leaves) when the observed disease severity was >0.6. Conclusions The model was highly accurate and robust in predicting the infection periods and dynamics of black‐rot epidemics. The model can be used for scheduling fungicide sprays in vineyards.
      PubDate: 2016-03-21T02:45:25.232311-05:
      DOI: 10.1002/ps.4277
       
  • Phenotypical and biochemical characterization of resistance for parasitic
           weed (Orobanche foetida Poir.) in radiation mutagenized mutants of
           chickpea
    • Authors: Ines Brahmi; Yassine Mabrouk, Guillaume Brun, Philippe Delavault, Omrane Belhadj, Philippe Simier
      Abstract: BACKGROUND Some radiation mutagenized chickpea mutants potentially resistant to the broomrape, Orobanche foetida Poir., were selected through field trials. The objectives of this work were to confirm resistance under artificial infestation, in pots and mini‐rhizotron systems, and to determine the developmental stages of broomrape affected by resistance and the relevant resistance mechanisms induced by radiation mutagenesis. RESULTS Among thirty mutants tested for resistance to O. foetida, five shared strong resistance in both pot experiments and mini‐rhizotrons systems. Resistance was not complete but the few individuals which escaped resistance displayed high disorders of shoot development. Results demonstrated a 2–3 fold decrease in stimulatory activity of root exudates towards broomrape seed germination in resistant mutants in comparison to non‐irradiated control plants and susceptible mutants. Resistance was associated to an induction of broomrape necrosis early during infection. When infested, most of resistant mutants shared enhanced levels in soluble phenolic contents, phenylalanine ammonia lyase activity, guaiacol peroxidase activity, polyphenol oxidase activity, in addition to glutathione and notably ascorbate peroxidase gene expression in roots. CONCLUSION Results confirmed enhanced resistance in chickpea radiation mutagenized mutants, and demonstrated resistance is rested on alteration of root exudation, presumed cell wall reinforcement and change in root oxidative status in response to infection.
      PubDate: 2016-03-21T02:45:22.563375-05:
      DOI: 10.1002/ps.4278
       
  • Genetic variation in target‐site resistance to pyrethroids and
           pirimicarb in Tunisian populations of the peach potato aphid, Myzus
           persicae (Sulzer) (Hemiptera: Aphididae)
    • Abstract: BACKGROUND We used molecular assays to diagnose resistance to pyrethroids and pirimicarb in samples of Myzus persicae from field crops or an insect suction trap in Tunisia. Genotypes for resistance loci were related to ones for polymorphic microsatellite loci in order to investigate breeding systems, patterns of genetic diversity and to inform resistance management tactics. RESULTS The kdr mutation L1014F conferring pyrethroid resistance was found in all samples. The M918T s‐kdr mutation also occurred in most samples, but only in conjunction with kdr. We discovered a previously unreported genotype heterozygous for L1014F but homozygous for M918T. Samples with modified acetylcholinesterase (MACE) conferring resistance to pirimicarb were less common but widespread. 16% of samples contained both the kdr and MACE mutations. Many unique microsatellite genotypes were found, suggesting that M. persicae is holocyclic in Tunisia. There were no consistent associations between resistance and microsatellite markers. CONCLUSION This first study of insecticide resistance in M. persicae in North Africa showed genetic variation in insecticide resistance within microsatellite multilocus genotypes (MLGMs) and the same resistance mechanisms to be present in different MLGMs. This contrasts with variation in northern Europe where M. persicae is fully anholocyclic. Implications for selection and control strategies are discussed.
      PubDate: 2016-03-16T03:16:28.066508-05:
      DOI: 10.1002/ps.4276
       
  • Increasing social welfare by taxing pesticide externalities in the Indian
           cotton sector
    • Authors: Livia Rasche; Alexander Dietl, Nikolinka Shakhramanyan, Divya Pandey, Uwe A. Schneider
      Abstract: Background Pesticide use in the Indian cotton industry has decreased with the introduction of Bt cotton, but rates are still high in comparison to other countries. The adoption of alternative strategies, such as integrated pest management, has been slow, even though benefits are potentially high, more so if the full costs of the external effects of the technologies are taken into account. In order to estimate true societal benefits of different strategies, we compare their external costs and economic performance under external cost taxation, using a state of the art partial equilibrium model of the Indian agricultural sector. Results Pesticide externalities lower social welfare in the Indian cotton sector by USD 400–2200 million, depending on the technologies employed. A full internalization decreases producer revenues by 100 USD/ha if only Bt cotton is used, and by 30 USD/ha if IPM is another option. Consumers don't start to lose surplus until 20‐70% are internalized, and losses are smaller if all technologies are available. Conclusions External pesticide costs can be internalized partially without substantially impacting consumer surplus while still increasing social welfare, but producers need to have access to and the knowledge to employ all available cotton production technologies to minimize losses.
      PubDate: 2016-03-15T06:41:54.747232-05:
      DOI: 10.1002/ps.4275
       
  • Frequency of Cry1F Resistance Alleles in Spodoptera frugiperda
           (Lepidoptera: Noctuidae) in Brazil
    • Authors: Juliano R Farias; David A. Andow, Renato J Horikoshi, Daniel Bernardi, Rebeca da S Ribeiro, Antonio R B do Nascimento, Antonio C dos Santos, Celso Omoto
      Abstract: BACKGROUND The frequency of resistance alleles is a major factor influencing the rate of resistance evolution. Here, we adapted the F2 screen procedure for Spodoptera frugiperda (J.E. Smith) with a discriminating concentration assay, and extended associated statistical methods to estimate the frequency of resistance to Cry1F protein in S. frugiperda in Brazil when resistance was not rare. RESULTS We show that F2 screen is efficient even when resistance frequency is 0.250. It was possible to screen 517 isoparental lines from 12 populations sampled in five states of Brazil during the first half of 2012. Western Bahia had the highest allele frequency of Cry1F resistance, 0.192, with a 95% confidence interval (CI) between 0.163 and 0.220. All other states had a similar and lower frequency varying from 0.042 in Paraná to 0.080 in Mato Grosso do Sul. CONCLUSION The high frequency in western Bahia may be related to year‐round availability of maize, the high population density of S. frugiperda, the lack of refuges, and the high adoption rate of Cry1F maize. Cry1F resistance alleles were not rare and occurred at frequencies that have already compromised the useful life of TC1507 maize in western Bahia.
      PubDate: 2016-03-15T05:51:16.334391-05:
      DOI: 10.1002/ps.4274
       
  • Movement and survival of Busseola fusca (Lepidoptera: Noctuidae) larvae
           within maize plantings with different ratios of non‐Bt and Bt seed
    • Authors: Annemie Erasmus; Jaco Marais, Johnnie Van den Berg
      Abstract: BACKGROUND Products of plant biotechnology, for example genetically modified Bt maize, provide useful tools for pest management. The benefits provided by insect resistant plants are, however, threatened by the evolution of resistance by target pest species. The high‐dose/refuge insect resistance management strategy (IRM) as well as seed mixtures are globally used as IRM strategies. Busseola fusca (Lepidoptera: Noctuidae), the target stem borer of Bt maize in Africa, evolved resistance to Bt maize expressing Cry1Ab protein in South Africa. Due to high larval mobility and subsequent sub‐lethal exposure of larvae moving between non‐Bt and Bt plants, more rapid resistance evolution has been proposed as a possibility with deployment of seed mixture strategies. RESULTS Laboratory and field studies were conducted to study B. fusca larval mobility. In the laboratory different scenarios of B. fusca larval movement between single gene (Cry1Ab) and stacked trait (Cry1A.105 and Cry2Ab2) Bt maize was studied. Data on larval survival and mass over time indicated that Cry proteins do not kill larvae above certain developmental stages. A 2‐year field study with the single‐gene and the stacked event was conducted using seed mixtures containing 5, 10, 15 and 20% non‐Bt seed as well as a control treatment (non‐Bt seed only). CONCLUSION Larval movement continued for five weeks and resulted in a significant incidence of Bt and non‐Bt damaged plants, indicating that the movement behaviour of B. fusca is of such a nature that seed mixtures as an IRM strategy may not be effective to delay resistance evolution.
      PubDate: 2016-03-15T05:51:10.19927-05:0
      DOI: 10.1002/ps.4273
       
  • Reducing the availability of food to control feral pigeons: changes in
           population size and composition
    • Abstract: BACKGROUND Since feeding by humans is one of the main food resources to pigeons (Columba livia), there is general agreement that public education that aims to reduce the food base may be the most feasible way to reduce pigeon abundance. However, except for the classic example of Basel, the method has rarely been tested or implemented. We provide results from a one‐year study in the city of Barcelona where we tested the effect of public education on pigeon population abundance and composition. RESULTS The quantity of food provided by people to pigeons was significantly reduced during the study. Feral pigeon density was reduced by 40% in the two experimental districts, but no variation was detected in the control district. Detailed analyses in one of the districts showed that the reduction was mainly related to the reduction in food availability but not to culling. Pigeons captured at the end of the experiment were larger than at the start of the study but body condition was reduced. CONCLUSION Results show the effectiveness of public information to manage feral pigeon populations in a large city and that control operations can exert important selection pressure on the population leading to changes in population composition.
      PubDate: 2016-03-07T00:30:54.913533-05:
      DOI: 10.1002/ps.4272
       
  • Simplified strigolactams as potent analogues of strigolactones for the
           seed germination induction of Orobanche cumana Wallr
    • Abstract: Background Strigolactones play an important role in the rhizosphere as signaling molecules stimulating the seed germination of parasitic weed seeds and hyphal branching of arbuscular micorrhiza and also act as hormones in plant roots and shoots. Strigolactone derivatives e.g. strigolactams could be used as suicidal germination inducers in the absence of a host crop for the decontamination of land infested with parasitic weed seeds. Results We report the stereoselective synthesis of novel strigolactams together with some of their critical physicochemical properties such as water solubility, hydrolytic stability, as well as their short soil persistence. In addition, we show that such strigolactams are potent germination stimulants of O. cumana parasitic weed seeds and do not affect the seed germination and the root growth of sunflower. Conclusions The novel strigolactam derivatives described here compare favorably with the corresponding GR‐28 strigolactones in term of biological activity and physicochemical properties. However, we believe strigolactone‐ and strigolactam‐ derivatives require further structural optimization to improve their soil persistence to demonstrate a potential for agronomical applications.
      PubDate: 2016-03-04T03:44:40.053989-05:
      DOI: 10.1002/ps.4268
       
  • Detection of Zymoseptoria tritici SDHI insensitive field isolates carrying
           the SdhC‐H152R and SdhD‐R47W substitutions
    • Abstract: BACKGROUND Succinate dehydrogenase inhibitor fungicides are important in the management of Zymoseptoria tritici in wheat. New active ingredients from this group of fungicides have been introduced recently and are widely used. Because the fungicides act at a single enzyme site, resistance development in Z. tritici is classified as medium‐to‐high risk. RESULTS Isolates from Irish experimental plots in 2015 were tested against the SDHI penthiopyrad during routine monitoring. The median of the population was approximately 2 x less sensitive than the median of the baseline population. Two of the 93 isolates were much less sensitive to penthiopyrad than the least sensitive of the baseline isolates. These isolates were also insensitive to most commercially available SDHIs. Analysis of the succinate dehydrogenase coding genes confirmed the presence of the substitutions SdhC‐H152R and SdhD‐R47W in the very insensitive isolates. CONCLUSION This is the first report showing that the SdhC‐H152R mutation detected in laboratory mutagenesis studies also exist in the field. The function and relevance of this mutation, combined with SdhD‐R47W, still needs to be determined.
      PubDate: 2016-03-04T03:44:29.807034-05:
      DOI: 10.1002/ps.4269
       
  • A historical perspective on the effects of trapping and controlling the
           muskrat (Ondatra zibethicus) in The Netherlands
    • Authors: E. Emiel van Loon; Daan Bos, Caspara.J. van Hellenberg Hubar, Ron C. Ydenberg
      Abstract: BACKGROUND Muskrat are considered a pest species in The Netherlands, and a year‐round control programme is in effect. We aimed to evaluate the effectiveness of this programme using historical data on catch and effort collected at a provincial scale. RESULTS The development of the catch differed between provinces, depending on the year of colonisation by muskrat and the investment of effort (measured as field hours). The catch did not peak in the same year for the various provinces, and provinces that were colonized earlier in time took longer to attain the peak catch. Trapping resulted in declining populations, but only after a certain threshold of annual effort in trapping had been surpassed. On average populations were observed to decline when the annual effort exceeded 1.4 field hour per km of waterway for several successive years. After having reached a phase of greater control, control organizations tended to reduce effort. CONCLUSION We conclude that control measures can make muskrat populations decline, provided that the effort is commensurate with the population size. Our study emphasizes that experimentation is needed to confirm the causality of the findings, to establish the relation with damage or safety risk and to derive an optimal control strategy.
      PubDate: 2016-03-04T03:44:25.908234-05:
      DOI: 10.1002/ps.4270
       
  • Sublethal effects of chlorantraniliprole on development, reproduction, and
           vitellogenin gene (CsVg) expression in the rice stem borer, Chilo
           suppressalis
    • Authors: Li Huang; Mingxing Lu, Guangjie Han, Yuzhou Du, Jianjun Wang
      Abstract: BACKGROUND The rice stem borer, Chilo suppressalis (Walker), is one of the most damaging rice pests in the world. The sublethal effects of chlorantraniliprole on development,reproduction, and mRNA expression levels of vitellogenin gene (CsVg) in C. suppressalis were investigated. RESULTS Exposure of sublethal concentrations of chlorantraniliprole (LC10 and LC30) to the third instar larvae significantly extended larvae duration, lowered mean weight of male pupae, and shortened male adult longevity. The pupae duration was significantly prolonged and the mean weight of female pupae was significantly lowered in treatment group of LC30. While there were no significant sublethal effects on either the adult emergence rate or the egg hatch, the pupation rates in treatment groups of LC10 (41.30%) and LC30 (23.98%) were significantly lower than that of the control (71.86%), and the LC10 and LC30 chlorantraniliprole significantly decreased fecundity by 32.18% and 52.94%, respectively. Furthermore, the expression levels of CsVg mRNA after exposure to LC10 and LC30 chlorantraniliprole significantly decreased by 42.52% and 47.84%, respectively, in 12‐h‐old female adults. CONCLUSION Sublethal concentrations of chlorantraniliprole adversely affect the development and reproduction of C. suppressalis. The down‐regulation of CsVg by chlorantraniliprole might have negative impacts on the fecundity of C. suppressalis.
      PubDate: 2016-03-04T03:44:18.144773-05:
      DOI: 10.1002/ps.4271
       
  • Eradication of Common Mynas Acridotheres tristis from Denis Island,
           Seychelles
    • Abstract: BACKGROUND In Seychelles the Common Myna has been shown to negatively impact endangered endemic birds, on Denis Island interfering with breeding attempts and attacking adult endemic birds at their nests. This stimulated an attempt to eradicate the island's mynas. RESULTS The eradication was undertaken in three phases, overall killing 1179 mynas and lasting 4 years. Decoy trapping was the most effective method of catching mynas but the last birds were shot. Decoy trapping was compromised by catches of non‐target species. Data collection from killed birds indicated that trapping did not favour either sex, and that most breeding occurred during the wetter season, November to March. CONCLUSIONS Eradication of mynas from small tropical islands is feasible. The Denis Island eradication was prolonged by difficulties in management and staffing. Using volunteers, the cost of the eradication was similar to that of eradicating rodents from the island. In future eradication attempts in Seychelles, possible food stress during the drier season (May to September) might facilitate trapping at this time. Habitat management, especially the removal of short mown grass, could enhance eradication progress. Continued monitoring is needed to confirm eradication and detect any immigration, and also to record responses in the endemic birds.
      PubDate: 2016-03-03T01:18:19.596826-05:
      DOI: 10.1002/ps.4263
       
  • Chemical modification of phenoxyfuranone‐type strigolactone mimic
           for selective effects on rice tillering or Striga hermonthica seed
           germination
    • Authors: Ikuo Takahashi; Kosuke Fukui, Tadao Asami
      Abstract: BACKGROUND We previously reported that a series of phenoxyfuranone compounds, designated “debranones”, mimic strigolactone (SL) activity. 4‐Bromodebranone (4BD) is a functionally selective SL mimic that reduces the number of shoot branches on rice more potently than GR24, a typical synthetic SL analogue, but does not induce seed germination in the root‐parasitic plant, Striga hermonthica. To enhance the selective activity of debranones in stimulating the seed germination of root‐parasitic plants, we prepared several analogues of 4BD in which the chlorine atom was substituted with an H atom at the o, m, or p position on the phenyl ring (designated 2‐, 3‐, or 4‐chlorodebranone, respectively) or had a bicyclic group instead of the phenyl ring. We evaluated the biological activities of the compounds with rice tillering assays and S. hermonthica seed germination assays. RESULTS Both assays showed that the substituent position affected the debranones’ efficiency, and among the monochlorodebranones, 2‐chlorodebranone was more effective than the other two isomers in both assays. When the activities of the bicyclic debranones were compared in the same two assays, one was more active than GR24 in the rice tillering assay. This debranone also stimulated the germination of S. hermonthica seeds. Thus, some debranone derivatives induced the germination of S. hermonthica seeds, although their activities were still ~1/20 that of GR24. CONCLUSION These results strongly suggest that further and rigorous structure–activity relationship studies of the debranones will identify derivatives that more potently stimulate the suicidal germination of S. hermonthica seeds.
      PubDate: 2016-03-01T01:50:23.190858-05:
      DOI: 10.1002/ps.4265
       
  • A psbA Mutation (Val219 to Ile) Causes Resistance to Propanil and
           Increased Susceptibility to Bentazon in Cyperus difformis
    • Abstract: BACKGROUND Propanil‐resistant (R) Cyperus difformis populations were recently confirmed in California rice fields. To date, propanil resistance in other weed species has been associated with enhanced aryl acylamidase (AAA)‐mediated propanil conversion into 3,4‐dichloroaniline. Our objectives were to determine the level of propanil resistance and cross‐resistance to other PSII inhibitors in C. difformis lines, and to elucidate the mechanism of propanil resistance. RESULTS The propanil‐R line had a 14‐fold propanil resistance and increased resistance to bromoxynil, diuron and metribuzin, but not to atrazine. The R line, however, displayed a four‐fold increased susceptibility to bentazon. Interestingly, S plants accumulated more 3,4‐dichloroaniline and were more injured by propanil and carbaryl (AAA‐inhibitor) applications than R plants, suggesting that propanil metabolism is not the resistance mechanism. psbA gene sequence analysis indicated a valine‐219‐isoleucine (Val219Ile) amino acid exchange in the propanil‐R chloroplast D1 protein. CONCLUSION The D1 Val219Ile modification in C. difformis causes resistance to propanil, diuron, metribuzin, and bromoxynil but increased susceptibility to bentazon, suggesting Val219Ile participates in binding of these herbicides. This is the first report of a higher plant exhibiting target‐site propanil resistance. Tank‐mixing bentazon and propanil, where permitted can control both propanil‐R and –S C. difformis and prevent the spread of the resistant phenotype.
      PubDate: 2016-03-01T01:42:53.820299-05:
      DOI: 10.1002/ps.4267
       
  • Survey of indigenous entomopathogenic fungi and evaluation of their
           pathogenicity against the carmine spider mite, Tetranychus cinnabarinus
           (Boisd.) and the whitefly, Bemisia tabaci (Genn.) biotype B
    • Authors: Emine Topuz; Fedai Erler, Emine Gumrukcu
      Abstract: BACKGROUND The carmine spider mite, Tetranychus cinnabarinus, and silverleaf whitefly, Bemisia tabaci, are serious pests of both field‐ and greenhouse‐grown crops in southwestern Turkey. Control of these pests has been heavily dependent upon chemical pesticides. Objectives of this study were to investigate the occurrence of indigenous entomopathogenic fungi (EPF) in field populations of T. cinnabarinus and B. tabaci, and to evaluate their pathogenicity against these pests. For this purpose, a survey of EPF isolated from field‐collected samples of both pests was carried out in Antalya in 2010 and 2011 using the dilution plating method. RESULTS Four indigenous Beauveria bassiana isolates (TUR1‐B, TUR2‐B, FIN1‐B, FIN2‐B) were recovered. In pathogenicity bioassays with T. cinnabarinus and B. tabaci biotype B, all the isolates tested were pathogenic to some of the biological stages of both pests in varying degrees. FIN1‐B and TUR1‐B caused mortalities of up to 50% and 45%, respectively, in adults of T. cinnabarinus and over 79% and 37%, respectively, in pupae of B. tabaci with 107 conidia mL−1 suspensions under laboratory conditions 10 days after inoculation. FIN2‐B and TUR2‐B had mortalities of 19.45% and 12.28%, respectively, in adults of T. cinnabarinus, and of 6.78% and 8.18%, respectively, in pupae of B. tabaci. All of the isolates had no effect on eggs of both species and larvae of the mite. CONCLUSION Overall results suggest that isolates FIN1‐B and TUR1‐B have potential for management of T. cinnabarinus and B. tabaci.
      PubDate: 2016-03-01T01:42:52.718154-05:
      DOI: 10.1002/ps.4266
       
  • Synthesis and evaluation of hydroxyazolopyrimidines as herbicides; the
           generation of amitrole in planta
    • Authors: John M. Clough; Richard P. Dale, Barry Elsdon, Timothy R. Hawkes, Bridget V. Hogg, Anushka Howell, Daniel P. Kloer, Karine Lecoq, Matthew M. W. McLachlan, Phillip J. Milnes, Timothy J. C. O'Riordan, Saranga Ranasinghe, Stephen E. Shanahan, Karen D. Sumner, Shanaaz Tayab
      Abstract: BACKGROUND Exploiting novel herbicidal modes of action is an important method to overcome the challenges faced by increasing resistance and regulatory pressure on existing commercial herbicides. Recent reports of inhibitors of enzymes in the non‐mevalonate pathway of isoprenoid biosynthesis led to the design of a novel class of azolopyrimidines which were assessed for their herbicidal activity. Studies were also undertaken to determine the mode of action responsible for the observed herbicidal activity. RESULTS In total, 30 novel azolopyrimidines were synthesised and their structures were unambiguously determined by 1H NMR, mass spectroscopy and X‐ray crystallographic analysis. The herbicidal activity of this new chemical class was assessed against six common weed species with compounds from this series displaying bleaching symptomology in post‐emergence tests. A structure‐activity relationship for the novel compounds was determined which showed that only those belonging to the hydroxytriazolopyrimidine sub‐class displayed significant herbicidal activity. Observed similarities between the bleaching symptomology displayed by these herbicides and amitrole suggested that hydroxytriazolopyrimidines could be acting as elaborate pro‐pesticides of amitrole, and this was subsequently demonstrated in plant metabolism studies using Amaranthus retroflexus. It was shown that selected hydroxytriazolopyrimidines which displayed promising herbicidal activity generated amitrole, with peak concentrations of amitrole generally being observed one day after application. Additionally, the herbicidal activity of selected compounds was profiled against tobacco plants engineered to overexpress 4‐diphosphocytidyl‐2C‐methyl‐D‐erythritol synthase (IspD) or lycopene β‐cyclase and the results suggested that, where significant herbicidal activity was observed, inhibition of IspD was not responsible for the activity. Tobacco plants which overexpressed lycopene β‐cyclase showed tolerance to amitrole and the two most herbicidally active triazolopyrimidines. CONCLUSIONS Inhibition of IspD leading to herbicidal activity has been ruled out as the mode of action for the hydroxytriazolopyrimidine class of herbicides. Additionally, tobacco plants which overexpressed lycopene β‐cyclase showed tolerance to amitrole which indicates that this is the main herbicidal mode of action for amitrole. Results from the metabolic fate study of selected hydroxytriazolopyrimidines suggested that the herbicidal activity displayed by these compounds is due to amitrole production, which was confirmed when tobacco plants overexpressing lycopene β‐cyclase also showed tolerance towards two triazolopyrimidines from this study.
      PubDate: 2016-02-26T02:27:52.394714-05:
      DOI: 10.1002/ps.4264
       
  • Clonostachys rosea reduces spot blotch in barley by inhibiting
           pre‐penetration growth and sporulation of Bipolaris sorokiniana
           without inducing resistance
    • Abstract: Background Several diseases threaten cereal production and fungicides are therefore widely used. Biological control is an environmentally friendly alternative and the fungus Clonostachys rosea is a versatile antagonist, effective against several plant diseases. We studied the ability of C. rosea to control barley leaf pathogens and the mechanisms behind the inhibition emphasising induced resistance. Results Under controlled conditions, spray application of C. rosea isolate IK726 to barley leaves reduced Bipolaris sorokiniana severity up to 70% when applied 24 h before or simultaneously as the pathogen, whereas application 24 h after the pathogen had no effect. IK726 also reduced the sporulation capacity of B. sorokiniana. Microscopy of B. sorokiniana infection revealed that IK726 primarily inhibited conidial germination and appressorium formation while further pathogen development and host defence reactions (papillae and fluorescent epidermal cells) were unaffected. Likewise, expression of defence‐related genes encoding PR‐proteins was unaltered. In addition to B. sorokiniana, IK726 also reduced infection by Drechslera teres and Rhynchosporium commune. Conclusion C. rosea acted as a protectant against three barley leaf pathogens. B. sorokiniana was directly inhibited by IK726 whereas induced resistance appeared not to be involved. Quantitative microscopy is a powerful tool for elucidating mechanisms involved in disease control.
      PubDate: 2016-02-23T00:21:19.887168-05:
      DOI: 10.1002/ps.4260
       
  • Reproduction of the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) B
           biotype in maize fields (Zea mays L.) in Brazil
    • Authors: Eliane D. Quintela; Aluana G. Abreu, Julyana F. dos S. Lima, Gabriel M. Mascarin, Jardel Barbosa dos Santos, Judith K. Brown
      Abstract: Background Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae) was observed to have completed its reproductive cycle from the egg to the adult on maize (Zea mays L.). Field and screen house studies were carried out to investigate the durability of this putative and unprecedented adaptation to a grass host. Results Analysis of the mitochondrial COI gene sequence identified the maize‐associated B. tabaci as the exotic B biotype (major clade North Africa‐Mediterranean‐Middle East). Results showed that whiteflies migrated from soybean crops and successfully established in maize plants. Females exhibited a preference for oviposition primarily on the 1st and 2nd leaves of maize but also were able to colonize developing leaves. A high, natural infestation on maize (193.3 individuals, all developmental stages) was observed within a 7.1‐cm2 designated ‘observation area’. Whiteflies collected from naturally infested maize leaves and allowed to oviposit on maize seedlings grown in a screen house, developed from egg to adulthood in 28.6  ±0.2 days. Conclusion This is the first report of the B biotype completing its development on maize plants. This surprising anomaly indicates that the B biotype is capable of adapting to monocotyledonous host plants, and importantly, broadens the host range to include at least one species in the Poaceae.
      PubDate: 2016-02-22T23:47:45.084418-05:
      DOI: 10.1002/ps.4259
       
  • Toxin stability improvement and toxicity increase against Dipteran and
           Lepidopteran larvae of Bacillus thuringiensis crystal protein Cry2Aa
    • Authors: Jihen Elleuch; Samir Jaoua, Carole Ginibre, Fabrice Chandre, Slim Tounsi, Raida Z. Zghal
      Abstract: Background Bacillus thuringiensis δ‐endotoxins are the most widely used biopesticides for controlling economically important crop pests and disease vectors. Improving its efficacy is of great benefit. Here, an improvement of Cry2Aa δ‐endotoxins toxicity was conducted via a cry gene over‐expression system using P20 from B. thuringiensis israelensis. Results The co‐expression of Cry2Aa with P20 witnessed a 7‐fold increase of its production yield in B. thuringiensis. Generated crystals showed to be significantly more toxic (505.207 µg · g−1, 1.99 mg · l−1 and 1.49 mg · l−1) than the P20‐lacking control (720.78 µg · g−1, 705.69 mg · l−1 and 508.51 mg · l−1) against Ephestia kuehniella, Aedes aegypti and Culex pipiens larvae, respectively. In vitro, processing experiments revealed a P20‐mediated protection of Cry2Aa against degradation under larval gut conditions. Thus, P20 could promote the maintenance of a tightly packaged conformation of Cry2Aa toxins in the larval midgut upon correct activation and binding to its membrane receptor. Conclusion Based on its resistance against excessive proteolysis, Cry2Aa δ‐endotoxins, produced in the presence of P20, could be considered as a successful control agent for E. kuehniella and an effective alternative for mosquitoes control implying its possible exploitation in pest management programs.
      PubDate: 2016-02-22T23:47:43.405893-05:
      DOI: 10.1002/ps.4261
       
  • Combining electrostatic powder with an insecticide: effect on stored
           product beetles and on the commodity
    • Authors: Christos G Athanassiou; Thomas N Vassilakos, Anna C. Dutton, Nicholas Jessop, David Sherwood, Garry Pease, Andreja Brglez, Clare Storm, Stanislav Trdan
      Abstract: BACKROUND The opportunity to reduce the amount of pirimiphos‐methyl applied to grain by formulating it in an electrostatic powder was investigated. The insecticidal efficacy of pirimiphos‐methyl in EC formulation or formulated using electrostatic powder (EP) as an inert carrier was investigated against; Sitophilus oryzae (L.), Oryzaephilus surinamensis (L.), Rhyzopertha dominica (F.) and Tribolium confusum Jacquelin du Val. Furthermore, the adhesive properties of EP, to rice, corn and wheat, together with the effect on bulk density and bread and pasta making properties were investigated. RESULTS The results showed that pirimiphos‐methyl formulated with EP provided better efficacy against adults when compared to EC formulation for O. surinamensis and T. confusum, but there was no difference for R. dominica. Progeny production was consistently lower in grain treated with the EP formulation than the EC. The adherence tests showed that EP remained on the kernels greater on hard wheat than on maize or rice. In most commodities EP did not alter the bulk density. Finally, the addition of EP did not affect flour and bread making properties, nor the pasta making properties. CONCLUSIONS The results of the present study suggest that an EP could be used to reduce the amount of pirimiphos‐methyl applied to grain for effective pest control with no detrimental effects on grain quality.
      PubDate: 2016-02-11T01:27:40.889661-05:
      DOI: 10.1002/ps.4255
       
  • Issue Information ‐ Aims and Scope
    • Pages: 1445 - 1445
      PubDate: 2016-06-23T09:22:43.839938-05:
      DOI: 10.1002/ps.4128
       
  • Issue Information ‐ Info Page
    • Pages: 1446 - 1446
      PubDate: 2016-06-23T09:22:38.606552-05:
      DOI: 10.1002/ps.4129
       
  • Issue Information ‐ ToC
    • Pages: 1447 - 1448
      PubDate: 2016-06-23T09:22:41.137815-05:
      DOI: 10.1002/ps.4130
       
  • Determining the drift potential of Venturi nozzles compared with standard
           nozzles across three insecticide spray solutions in a wind tunnel
    • Authors: J Connor Ferguson; Rodolfo G Chechetto, Chris C O'Donnell, Gary J Dorr, John H Moore, Greg J Baker, Kevin J Powis, Andrew J Hewitt
      Pages: 1460 - 1466
      Abstract: BACKGROUND Previous research has sought to adopt the use of drift‐reducing technologies (DRTs) for use in field trials to control diamondback moth (DBM) Plutella xylostella (L.) (Lepidoptera: Plutellidae) in canola (Brassica napus L.). Previous studies observed no difference in canopy penetration from fine to coarse sprays, but the coverage was higher for fine sprays. DBM has a strong propensity to avoid sprayed plant material, putting further pressure on selecting technologies that maximise coverage, but often this is at the expense of a greater drift potential. This study aims to examine the addition of a DRT oil that is labelled for control of DBM as well and its effect on the drift potential of the spray solution. The objectives of the study are to quantify the droplet size spectrum and spray drift potential of each nozzle type to select technologies that reduce spray drift, to examine the effect of the insecticide tank mix at both (50 and 100 L ha−1) application rates on droplet size and spray drift potential across tested nozzle type and to compare the droplet size results of each nozzle by tank mix against the drift potential of each nozzle. RESULTS The nozzle type affected the drift potential the most, but the spray solution also affected drift potential. The fine spray quality (TCP) resulted in the greatest drift potential (7.2%), whereas the coarse spray quality (AIXR) resulted in the lowest (1.3%), across all spray solutions. The spray solutions mixed at the 100 L ha−1 application volume rate resulted in a higher drift potential than the same products mixed at the 50 L ha−1 mix rate. The addition of the paraffinic DRT oil was significant in reducing the drift potential of Bacillus thuringiensis var. kurstkai (Bt)‐only treatments across all tested nozzle types. The reduction in drift potential from the fine spray quality to the coarse spray quality was up to 85%. CONCLUSION The addition of a DRT oil is an effective way to reduce the spray solution drift potential across all nozzle types and tank mixes evaluated in this study. The greatest reduction in drift potential can be achieved by changing nozzle type, which can reduce the losses of the spray to the surrounding environment. Venturi nozzles greatly reduce the drift potential compared with standard nozzles by as much as 85% across all three insecticide spray solutions. Results suggest that a significant reduction in drift potential can be achieved by changing the nozzle type, and can be achieved without a loss in control of DBM. © 2016 Society of Chemical Industry
      PubDate: 2016-02-02T04:31:47.444914-05:
      DOI: 10.1002/ps.4214
       
  • Molecular modeling of sulfoxaflor and neonicotinoid binding in insect
           nicotinic acetylcholine receptors: impact of the Myzus β1 R81T
           mutation
    • Authors: Nick X Wang; Gerald B Watson, Michael R Loso, Thomas C Sparks
      Pages: 1467 - 1474
      Abstract: BACKGROUND Sulfoxaflor (Isoclast™ active), a new sulfoximine‐class insecticide, targets sap‐feeding insect pests, including those resistant to neonicotinoids. Sulfoxaflor acts on the insect nicotinic acetylcholine receptor (nAChR) in a distinct manner relative to neonicotinoids. Unlike any of the neonicotinoids, sulfoxaflor has four stereoisomers. A homology model of Myzus persicae (green peach aphid) based on the ACh binding protein from Aplysia californica, overlaid with M. persicae nAChR sequence (α2 and β1 subunits) was used to investigate the interactions of the sulfoxaflor stereoisomers with WT and R81T versions of the nAChR. RESULTS Whole‐molecule van der Waals interactions are highly correlated with the binding affinity for the neonicotinoids and correctly predict the rank order of binding affinity for neonicotinoids and sulfoxaflor. The R81T mutation in M. persicae nAChR is predicted to have much less effect on binding of sulfoxaflor's stereoisomers than that of the neonicotinoids. CONCLUSION All four stereoisomers predictably contribute to the activity of sulfoxaflor. The WT and R81T nAChR homology models suggest that changes in a whole‐molecule electrostatic energy component can potentially explain the effects of this target‐site mutation on the pattern of reduced efficacy for the modeled neonicotinoids, and provide a basis for the reduced effect of this mutation on sulfoxaflor. © 2016 Society of Chemical Industry
      PubDate: 2016-02-24T04:22:47.081414-05:
      DOI: 10.1002/ps.4220
       
  • Mechanism of leaf‐cutting ant colony suppression by fipronil used in
           attractive toxic baits
    • Authors: Lailla C Gandra; Karina D Amaral, Joel C Couceiro, Terezinha MC Della Lucia, Raul NC Guedes
      Pages: 1475 - 1481
      Abstract: BACKGROUND Attractive toxic baits are the prevailing method for managing leaf‐cutting ants in the eucalypt forests planted for the production of pulp, paper, timber and charcoal. For successful use in these baits, the insecticidal compounds need to circumvent the typical defences of the eusocial leaf‐cutting ants. The challenge is to have an insecticide in the bait that will not directly harm and/or compromise foraging workers, but that will eventually suppress the colony. These underlying mechanisms are poorly known, and here the potential mechanism of fipronil activity in toxic baits for leaf‐cutting ants was assessed using colonies of the representative Neotropical Acromyrmex subterraneus subterraneus (Forel, 1893). RESULTS Although forager activity was not directly impaired by fipronil, the insecticide affected forager nestmate interactions (auto‐ and allogrooming) and waste removal and, more importantly, greatly affected the minor workers, impairing their activities of fungus garden cultivation and progeny handling. The fast decay of the fungus garden compromised the sustainability of the colonies, ultimately leading to their demise within 8 days. CONCLUSION The behavioural effects of sublethal insecticide exposure towards minor workers are the main determinants of insecticide activity as ant baits and should be targeted in developing such compounds. © 2016 Society of Chemical Industry
      PubDate: 2016-02-29T06:51:00.643182-05:
      DOI: 10.1002/ps.4239
       
  • Prevalence of entomophthoralean fungi (Entomophthoromycota) of aphids in
           relation to developmental stages
    • Pages: 1566 - 1571
      Abstract: BACKGROUND Transmission of fungal pathogens of aphids may be affected by the host developmental stage. Brassica and Lactuca sativa L. crops were sampled in Santa Fe, Argentina, to determine the prevalence of fungal‐diseased aphids and investigate the differences between developmental stages of aphids. RESULTS The fungal pathogens identified were Zoophthora radicans (Bref.) A. Batko, Pandora neoaphidis (Remaud. & Hennebert) Humber and Entomophthora planchoniana Cornu. Their prevalence on each crop was calculated. The numbers of infected aphids were significantly different between the different developmental stages on all crops except B. oleracea var. botrytis L. CONCLUSIONS The entomophthoralean fungi identified are important mortality factors of aphids on horticultural crops in Santa Fe. The numbers of infected nymphs and adults were significantly different, nymphs being the most affected developmental stage. © 2015 Society of Chemical Industry
      PubDate: 2016-01-07T06:40:12.78161-05:0
      DOI: 10.1002/ps.4188
       
  • Early perception of stink bug damage in developing seeds of
           field‐grown soybean induces chemical defences and reduces bug attack
           
    • Authors: Romina Giacometti; Jesica Barneto, Lucia G Barriga, Pedro M Sardoy, Karina Balestrasse, Andrea M Andrade, Eduardo A Pagano, Sergio G Alemano, Jorge A Zavala
      Pages: 1585 - 1594
      Abstract: BACKGROUND Southern green stink bugs (Nezara viridula L.) invade field‐grown soybean crops, where they feed on developing seeds and inject phytotoxic saliva, which causes yield reduction. Although leaf responses to herbivory are well studied, no information is available about the regulation of defences in seeds. RESULTS This study demonstrated that mitogen‐activated protein kinases MPK3, MPK4 and MPK6 are expressed and activated in developing seeds of field‐grown soybean and regulate a defensive response after stink bug damage. Although 10–20 min after stink bug feeding on seeds induced the expression of MPK3, MPK6 and MPK4, only MPK6 was phosphorylated after damage. Herbivory induced an early peak of jasmonic acid (JA) accumulation and ethylene (ET) emission after 3 h in developing seeds, whereas salicylic acid (SA) was also induced early, and at increasing levels up to 72 h after damage. Damaged seeds upregulated defensive genes typically modulated by JA/ET or SA, which in turn reduced the activity of digestive enzymes in the gut of stink bugs. Induced seeds were less preferred by stink bugs. CONCLUSION This study shows that stink bug damage induces seed defences, which is perceived early by MPKs that may activate defence metabolic pathways in developing seeds of field‐grown soybean. © 2015 Society of Chemical Industry
      PubDate: 2016-01-04T09:06:24.396806-05:
      DOI: 10.1002/ps.4192
       
  • Efficacy of selected food‐safe compounds to prevent infestation of
           the ham mite, Tyrophagus putrescentiae (Schrank) (Acarina: Acaridae), on
           southern dry‐cured hams
    • Authors: Salehe Abbar; Barbara Amoah, M Wes Schilling, Thomas W Phillips
      Pages: 1604 - 1612
      Abstract: BACKGROUND Tyrophagus putrescentiae (Schrank) is a serious mite pest of dried meats and cheeses. Infestations of T. putrescentiae are controlled with the fumigant methyl bromide, which is an ozone‐depleting substance and is currently being banned in most countries. Effective alternatives to methyl bromide are needed. The objective of this research was to use laboratory assays to investigate the effectiveness of food‐safe compounds for preventing infestation of T. putrescentiae on dry‐cured hams. RESULTS Ham pieces dipped in solutions of either propylene glycol (1,2‐propanediol), lard, ethoxyquin or butylated hydroxytoluene prevented or significantly reduced mite population growth. Behavioral assays revealed that more mites oriented to the untreated control ham cubes, and more eggs were laid on these untreated ham cubes, compared with cubes treated with various dips. Our results also indicated that a combination of carrageenan + propylene glycol alginate + 40% propylene glycol was effective in reducing mite numbers on whole aging hams compared with untreated whole hams. CONCLUSIONS Several food‐safe compounds can prevent infestation of T. putrescentiae on dry‐cured hams and may represent alternatives for managing this pest. © 2015 Society of Chemical Industry
      PubDate: 2016-01-29T05:07:30.787873-05:
      DOI: 10.1002/ps.4196
       
  • Landscape effects on the abundance and larval diet of the polyphagous pest
           Helicoverpa armigera in cotton fields in North Benin
    • Authors: Noelline Tsafack; Audrey Alignier, Graham P Head, Jae H Kim, Michel Goulard, Philippe Menozzi, Annie Ouin
      Pages: 1613 - 1626
      Abstract: BACKGROUND The noctuid Helicoverpa armigera is one of the key cotton pests in the Old World. One possible pest regulation method may be the management of host crop in the landscapes. For polyphagous pests such as H. armigera, crop diversity and rotations can offer sequential and alternate resources that may enhance abundance. We explore the impact of landscape composition and host crop diversity on the abundance and natal host plant use of H. armigera in northern Benin. RESULTS Host plant diversity at the largest scale examined (500 m diameter) was positively correlated with H. armigera abundance. Host plant diversity and the cover of tomato crops were the most important variables in relation to high abundance of H. armigera. Host plant (cotton, maize, tomato, sorghum) proportions and C3 versus C4 plants did not consistently correlate positively with H. armigera abundance. Moth proportion derived from cotton‐fed larvae was low, 15% in 2011 and 11% in 2012, and not significantly related to H. armigera abundance. CONCLUSION Cotton crop cover was not significantly related to H. armigera abundance and may be considered as a sink crop. Landscape composition and sequential availability of host plants should be considered as keys factors for further studies on H. armigera regulation. © 2015 Society of Chemical Industry
      PubDate: 2016-02-03T07:52:25.0487-05:00
      DOI: 10.1002/ps.4197
       
 
 
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