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Journal Cover Pest Management Science
  [SJR: 1.258]   [H-I: 86]   [4 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1526-498X - ISSN (Online) 1526-4998
   Published by John Wiley and Sons Homepage  [1611 journals]
  • A glycoprotein α-amylase inhibitor from Withania somnifera differentially
           inhibits various α-amylases and affects growth and development of
           Tribolium castaneum
    • Authors: Sainath S. Kasar; Kiran R. Marathe, Amey J. Bhide, Abhijeet P. Herwade, Ashok P. Giri, Vijay L. Maheshwari, Pankaj K. Pawar
      Abstract: BACKGROUNDIdentification and characterization of plant defensive molecules enrich our resources to design crop protection strategies. In particular, plant derived proteinaceous inhibitor(s) ofinsect digestive enzymes appear to be a safe, sustainable and attractive option.RESULTSA glycoprotein having non-competitive α-amylase inhibitory activity with molecular weight 8.3 kDa was isolated and purified from seeds of Withania somnifera (WSAI). Its mass spectrometry analysis revealed 59% sequence coverage with Wrightide II type α-AI from Wrightia religiosa. A dose dependent inhibition of α-amylases from Aspergillus oryzae, Bacillus subtilis, Helicoverpa armigera and Tribolium castaneum was recorded. Interestingly, WSAI did not inhibit human salivary α-amylase significantly. When adults of T. castaneum were fed with WSAI (1.6 mg/g), decrease in consumption, growth and efficiency of conversion of ingested food were evident along with over 4-fold elevations in feeding deterrence index. A decline in larval residual α-amylase activity after feeding of WSAI resulted into reduction of longevity of T. castaneum.CONCLUSIONStudy reflects significance of WSAI to affect the overall growth and development of T. castaneum. Pre and post-harvest pest resistive capability makes WSAI a potential candidate for insect pest management. Further, effectiveness of this inhibitor could be explored either in formulations or through transgenic approach.
      PubDate: 2016-10-22T00:35:22.234722-05:
      DOI: 10.1002/ps.4467
  • Synthesis and Biological Activity of Pyridazine Amides, Hydrazones and
    • Authors: Ann M. Buysse; Maurice C. H. Yap, Ricky Hunter, Jonathan Babcock, Xinpei Huang, Marshall H. Parker
      Abstract: BACKGROUNDOptimization studies on compounds initially designed to be herbicides led to the discovery of a series of [6-(3-pyridyl)pyridazin-3-yl]amides exhibiting aphicidal properties. Systematic modifications of the amide moiety as well as the pyridine and pyridazine rings were carried out to determine if these changes could improve insecticidal potency.RESULTSStructure-activity relationship (SAR) studies showed that changes to the pyridine and pyridazine rings generally resulted in a significant loss of insecticidal potency against green peach aphids (Myzus persicae (Sulzer) and cotton aphids (Aphis gossypii (Glover). However, replacement of the amide moiety with hydrazines, hydrazones, or hydrazides appeared to be tolerated, with small aliphatic substituents being especially potent.CONCLUSIONSA series of aphicidal [6-(3-pyridyl)pyridazin-3-yl]amides were discovered as a result of random screening of compounds that were intially investigated as herbicides. Follow-up studies of the structure activity relationship of these [6-(3-pyridyl)pyridazin-3-yl]amides showed that biosteric replacement of the amide moiety was widely tolerated suggesting that further opportunities for exploitation may exsist for this new area of insecticidal chemistry. Insecticidal efficacy from the original hit, compound 1, to the efficacy of compound 14 produced greater than 10-fold potency improvement against Aphis gossypii and greater than 14-fold potency improvement against Myzus persicae.
      PubDate: 2016-10-21T02:30:36.075486-05:
      DOI: 10.1002/ps.4465
  • Comparison of ingestion and topical application of insecticides against
           the common bed bug, Cimex lectularius (Hemiptera: Cimicidae)
    • Authors: Angela Sierras; Coby Schal
      Abstract: BACKGROUNDThe global prevalence of Cimex lectularius infestations has challenged current intervention efforts, as pyrethroid resistance has become ubiquitous, availability of labeled insecticides for bed bugs is limited, and non-chemical treatment options, such as heat, are often unaffordable. We evaluated representative insecticides toward the goal of developing a novel, ingestible liquid bait for hematophagous arthropods.RESULTSLC50 values were estimated for adult males and first instar nymphs of an insecticide-susceptible strain for abamectin, clothianidin, fipronil and indoxacarb, after ingestion from an in vitro feeder. LD50 values were calculated based on the ingested blood volume. Ingested abamectin, clothianidin and fipronil caused rapid mortality in both life stages. Fipronil was ~43-fold more effective by ingestion than by topical application. Indoxacarb and its bioactive metabolite decarbomethoxyllated JW062 (DCJW) were ineffective at causing bed bug mortality even at concentrations as high as 1000 ng mL−1 blood.CONCLUSIONSFipronil, clothianidin and abamectin have potential for being incorporated into a liquid bait for bed bug control; indoxacarb and DCJW were not effective. Bed bugs are a good candidate for an ingestible liquid bait because systemic formulations generally require less active ingredient than residual sprays, they remain contained and more effectively target hematophagous arthropods.
      PubDate: 2016-10-21T02:00:38.522087-05:
      DOI: 10.1002/ps.4464
  • The Rise and Future of Glyphosate and Glyphosate-Resistant Crops
    • Authors: Jerry M. Green
      Abstract: Glyphosate and glyphosate-resistant crops had a revolutionary impact on weed management practices, but the epidemic of glyphosate-resistant (GR) weeds is rapidly decreasing the value of these technologies. In areas that fully adopted glyphosate and GR crops, GR weeds evolved and glyphosate and glyphosate traits now must be combined with other technologies. The chemical company solution is to combine glyphosate with other chemicals, and the seed company solution is to combine glyphosate resistance with other traits. Unfortunately, companies have not discovered a new commercial herbicide mode-of-action for over 30 years and have already developed or are developing traits for all existing herbicide types with high utility. Glyphosate mixtures and glyphosate trait combinations will be the mainstays of weed management for many growers, but are not going to be enough to keep up with the capacity of weeds to evolve resistance. Glufosinate, auxin, HPPD-inhibiting and other herbicide traits, even when combined with glyphosate resistance, are incremental and temporary solutions. Herbicide and seed businesses are not going to be able to support what critics call the chemical and transgenic treadmills for much longer. The long time without the discovery of a new herbicide mode-of-action and the epidemic of resistant weeds is forcing many growers to spend much more to manage weeds and creating a worst of times, best of times predicament for the crop protection and seed industry.
      PubDate: 2016-10-18T22:55:21.423423-05:
      DOI: 10.1002/ps.4462
  • Perspectives on the Agrochemical Industry and Agrochemical Discovery
    • Authors: Thomas C Sparks; Beth A Lorsbach
      Abstract: Agrochemicals have been critical to the production of food and fiber, as well as the control of vectors of disease. The need for the discovery and development of new agrochemicals continues unabated due to the loss of existing products through the development of resistance, the desire for products with more favorable environmental and toxicological profiles, shifting pest spectrums, and changing agricultural needs and practices. As presented in the associated analysis of the agrochemical industry, the rising costs and complexities of agrochemical discovery has, in part, led to increasing consolidation, especially in the US and Europe. However, as demonstrated by the present analysis, the discovery of new agrochemicals continues in spite of the challenges.
      PubDate: 2016-10-18T01:56:01.893395-05:
      DOI: 10.1002/ps.4457
    • Authors: Sharon Downes; Darren Kriticos, Hazel Parry, Cate Paull, Nancy Schellhorn, Myron P. Zalucki
      Abstract: Helicoverpa armigera is a major pest of agriculture, horticulture and floriculture throughout the old world and recently invaded parts of the new world.We overview of the evolution in thinking about the application of area-wide approaches to assist with its control by the Australian Cotton Industry to highlight important lessons and future challenges to achieving the same in the New World. An over-reliance of broad-spectrum insecticides led to Helicoverpa spp. in Australian cotton rapidly became resistant to DDT, synthetic pyrethroids, organophosphates, carbamates and endosulfan. Voluntary strategies were developed to slow the development of insecticide resistance, which included rotating chemistries and basing spray decisions on thresholds. Despite adoption of these practices, insecticide resistance continued to develop until the introduction of genetically modified cotton provided a platform for augmenting Integrated Pest Management in the Australian cotton industry. Compliance with mandatory resistance management plans for Bt cotton necessitated a shift from pest control at the level of individual fields or farms towards a coordinated area-wide landscape approach. Our take home message for control of H. armigera is that resistance management is essential in genetically modified crops and must be season long and area-wide to be effective.
      PubDate: 2016-10-17T23:00:21.904865-05:
      DOI: 10.1002/ps.4461
  • Computational Design of Novel Inhibitors to Overcome Weed Resistance
           Associated with Acetohydroxyacid Synthase (AHAS) P197L Mutant
    • Authors: Ren-Yu Qu; Jing-Fang Yang, Yu-Chao Liu, Qiong Chen, Ge-Fei Hao, Cong-Wei Niu, Zhen Xi, Guang-Fu Yang
      Abstract: BACKGOUNDAcetohydroxyacid synthase (AHAS; EC is the first common enzyme in the biosynthetic pathway leading to the branched-chain amino acids in plants and a wide range of microorganisms. With the long-term and wide application of AHAS inhibitors, weed resistance is becoming a global problem, which leads to an urgent demand for novel inhibitors to antagonize both wild-type and resistant AHAS.RESULTSPyrimidinyl-Salicylic acid derivatives, as one of the main classes of commercial AHAS herbicides, show potential anti-resistant bioactivity to wild-type and P197L mutant. In current work, a series of novel 2-benzoyloxy- 6-pyrimidinyl salicylic acid derivatives were designed through fragment-based drug discovery (FBDD). Fortunately, the newly synthesized compounds showed a good inhibitory activity against both wild-type and P197L mutant. Some compounds not only had a lower resistance factor value, but also showed an excellent inhibitory activity against wild type AHAS and P197L mutant. Furthermore greenhouse experiments showed compound 11 m displayed almost 100% inhibition against both wild-type and high-resistant Descurainia sophia at the dosage of 150 present work indicated that the 2-benzoyloxy- 6-pyrimidinyl salicylic acid motif was well worth further optimization. And compound 11 m can be used as a potential anti-resistant AHAS herbicide which requires further research.
      PubDate: 2016-10-17T03:06:15.66104-05:0
      DOI: 10.1002/ps.4460
  • Natural Products, Their Derivatives, Mimics and Synthetic Equivalents:
           Role in Agrochemical Discovery
    • Authors: Thomas C. Sparks; Donald R. Hahn, Negar V. Garizi
      Abstract: Natural products (NPs) have a long history as a source of, and inspiration for, novel agrochemcials. Many of the existing herbicides, fungicides and insecticides have their origins in a wide range of NPs from a variety of sources. Due to the changing needs of agriculture, shifts in pest spectrum, development of resistance and evolving regulatory requirements, the need for new agrochemical tools remains as critical as ever. As such, NPs continue to be an important source of models and templates for the development of new agrochemicals, demonstrated by the fact that NP models exist for many of the pest control agents that were discovered by other means. Interestingly, there appear to be distinct differences in the success of different NP sources for different pesticide uses. While a few microbial NPs have been important starting points in recent discoveries of some insecticidal agrochemicals, historically plant sources have contributed the most to the discovery of new insecticides. In contrast, fungi have been the most important NP sources for new fungicides. Like insecticides, plant sourced NPs have made the largest contribution to herbicide discovery. Available data on 2014 global sales and numbers of compounds in each class of pesticides indicate that the overall impact of NPs to the discovery of herbicides has been relatively modest compared to impact observed for fungicides and insecticides. However, as new sourcing and approaches to NP discovery evolve, the impact of NPs in all agrochemical arenas will continue to expand.
      PubDate: 2016-10-14T00:40:24.9129-05:00
      DOI: 10.1002/ps.4458
  • Spider (Araneae) Predations on White-Backed Planthopper Sogatella
           furcifera in Subtropical Rice Ecosystems, China
    • Authors: Xue-Qin Wang; Guang-Hua Wang, Zeng-Rong Zhu, Qi-Yi Tang, Yang Hu, Fei Qiao, Kong Luen Heong, Jia-an Cheng
      Abstract: BACKGROUNDSpiders are effective biological control agents in rice ecosystems, but the comparative study of predations among main spider species under field conditions have not been fully explored since lack of practical methodology. In this study, more than 6000 spiders of dominant species were collected from subtropical rice ecosystems to compare their predations on Sogatella furcifera (Horváth) using DNA based gut content analysis.RESULTSThe positive rates for all spider taxa were closely related to prey densities, as well as their behaviors and niches. The relationships of positive rates to prey planthopper densities for Pardosa pseudoannulata (Bö Str.), Coleosoma octomaculata (Bö Str.), Tetragnatha maxillosa Thorell and Ummeliata insecticeps (Bö Str.) in field conditions could be described with saturated response curves. Quantitative comparisons of predations among the 4 spider species confirmed that P. pseudoannulata and C. octomaculata were more rapacious than U. insecticeps and T. maxillosa in field conditions. The comparison of ratio of spider to WBPH and positive rates between fields revealed that biological control by spiders could be effectively integrated with variety resistance.CONCLUSIONThe generalist spiders could follow up WBPH population in time and assemblages of spiders cooperated with variety resistance could effectively suppress WBPH population.
      PubDate: 2016-10-14T00:06:06.016243-05:
      DOI: 10.1002/ps.4459
  • Use of an individual-based simulation model to explore and evaluate
           potential insecticide resistance management strategies
    • Authors: Russell Slater; Pierre Stratonovitch, Jan Elias, Mikhail A. Semenov, Ian Denholm
      Abstract: BACKGROUNDTools with the potential to predict risks of insecticide resistance and aid the evaluation and design of resistance management tactics are of value to all sectors of the pest management community. Here we describe use of a versatile individual-based model of resistance evolution to simulate how strategies employing single and multiple insecticides influence resistance development in the pollen beetle, Meligethes aeneus.RESULTSUnder repeated exposure to a single insecticide, resistance evolved faster to a pyrethroid (lambda-cyhalothrin) than to a pyridine azomethane (pymetrozine), due to difference in initial efficacy. A mixture of these compounds delayed resistance compared to use of single products. The effectiveness of rotations depended on the sequence in which compounds were applied in response to pest density thresholds. Effectiveness of a mixture strategy declined with reductions in grower compliance. At least 50% compliance was needed to cause some delay in resistance development.CONCLUSIONNo single strategy meets all requirements for managing resistance. It is important to evaluate factors that prevail under particular pest management scenarios. The model used here provides operators with a valuable means for evaluating and extending sound resistance management advice, as well as understanding needs and opportunities offered by new control techniques.
      PubDate: 2016-10-12T20:50:28.250307-05:
      DOI: 10.1002/ps.4456
  • Comparative metabolomics analysis of Callosobruchus chinensis larvae under
           hypoxia, hypoxia/hypercapnia and normoxia
    • Authors: Sufen Cui; Lei Wang, Jiangping Qiu, Zhicheng Liu, Xueqing Geng
      Abstract: BACKGOUNDThe tolerance to low oxygen (hypoxia) and high carbon dioxide (hypercapnia) is criticalfor insect control. On the basis of bioassay, metabolism profiles were built to dissect adaptive mechanism in bean weevil under hypoxia, hypoxia/hypercapnia, and normoxia usinggas chromatography–time-of-flight mass spectrometry (GC–TOF–MS).RESULTThe growth and development of bean weevils were suppressed significantly by two hypoxia situations, and hypercapnia enhanced the mortality, but after 24-d exposure, the surviving insects emerged adults earlier than those under hypoxia only. Metabolism profiles also showed striking difference in metabolites among three groups, both quantitatively and qualitatively. A total of 61 metabolites changed significantly in three pairs of comparison, among them, 40 were in hypoxia and 37 in hypoxia/hypercapnia relative to control groups, 16 metabolites were found between two treatments. Increased metabolites were mainly carbohydrates, amino acids and organic acids, while free fatty acids were decreased. Furthermore, the changes were further strengthened by the addition of hypercapnia, but excluding free fatty acids.CONCLUTIONOur findings showed bean weevil has high tolerance to hypoxia, even hypoxia/hypercapnia at biologically achievable levels and provides more direct evidence for stored-product insect mechanism regulation under hypoxia stress, especially free fatty acid regulation by hypercapnia, but not hypoxia.
      PubDate: 2016-10-08T08:20:46.92898-05:0
      DOI: 10.1002/ps.4455
  • Detecting pyrethroid resistance in predatory mites inhabiting soil and
           litter: An in vitro test
    • Authors: Marine El Adouzi; Olivier Bonato, Lise Roy
      Abstract: BACKGROUNDWhile resistance against insecticides is widely known in pest arthropods, it remains poorly known in non-target arthropods of the same agrosystems. This may be of crucial importance in the context of organic pest management or IPM: first, stopping of pesticide pressure during farm conversion may lead to important rearrangements of non-target communities due to fitness cost of resistance in populations of some species. Second, resistant biological agents may be useful to farms with low synthetic pesticide use. Communities of mesostigmatid mites, encompassing numerous predatory species, are supposed to be involved in important ecological processes in both crop soils and animal litter/manure.RESULTSHere we provide a tarsal-contact method for assessing resistance in different populations from various species of mesostigmatid mites. Analyses of data from repeated tests on three populations from different mesostigmatid families proved the method to be robust and able to generate consistent and reliable mortality percentages according to insecticide concentration.CONCLUSIONOur bioassay system allows for both one-shot estimate of pyrethroid sensitivity in mite populations and estimation of how it changes over time, making possible survival analyses and assessment of recovery from knockdown. The rating system retained makes it possible to score response to insecticides in a consistent and standard way in species from different mesostigmatid families.
      PubDate: 2016-10-08T08:10:22.892811-05:
      DOI: 10.1002/ps.4454
  • Combined use of Bacillus subtilis strain B-001 and bactericide for the
           control of tomato bacterial wilt
    • Authors: Di Peng; Kun Luo, Huidan Jiang, Yanan Deng, Lianyang Bai, Xiaomao Zhou
      Abstract: BACKGROUNDTomato bacterial wilt caused by Ralstonia solanacearum poses a serious threat to tomato production. However, no effective control measures are available. In this study, we combined the bactericide Saisentong with an effective biological control agent Bacillus subtilis B-001 to control tomato bacterial wilt under greenhouse and field conditions.RESULTSGrowth of B-001 in vitro was unaffected by Saisentong. In greenhouse experiments, the combined application of B-001and Saisentong via root irrigation or spray resulted in better disease control compared with either agent alone. In two fieldtrials, at a concentration of 400 to 500 mg kg−1 Saisentong, the combination treatment was more effective than expected and showed a synergistic effect. A lower concentration of Saisentong (200 or 300 mg kg−1) in combination with B-001 resulted in antagonistic effect. However, disease control was significantly greater compared with either treatment alone.CONCLUSIONThe combination of Saisentong and B-001 effectively controls tomato bacterial wilt. The integrated strategy represents a promising new tool to control the disease.
      PubDate: 2016-10-08T04:00:42.513302-05:
      DOI: 10.1002/ps.4453
  • Evaluation of systemic neonicotinoid insecticides for the management of
           the Asian citrus psyllid Diaphorina citri on containerized citrus
    • Authors: Frank J. Byrne; Matthew P. Daugherty, Elizabeth E. Grafton-Cardwell, James A. Bethke, Joseph G. Morse
      Abstract: BACKGROUNDStudies were conducted to evaluate uptake and retention of 3 systemic neonicotinoid insecticides, dinotefuran, imidacloprid, and thiamethoxam, in potted citrus nursery plants treated at standard label rates. Infestation of these plants placed at a field site with moderate levels of Asian citrus psyllid (ACP) was monitored for 14 weeks following treatments and insecticide residues in leaf tissue were quantified using ELISA. Bioassays were conducted using leaves harvested on various dates post-treatment to compare the efficacies of residues against adult ACP.RESULTSResidues of the 3 neonicotinoids were detected in leaf tissues within 1 week after treatment. Peak concentrations established at 1 week for imidacloprid and dinotefuran and at 2 weeks for thiamethoxam. Imidacloprid and thiamethoxam outperformed the control and dinotefuran treatments at protecting trees from infestations by ACP eggs and nymphs. For a given insecticide concentration in leaf tissue, thiamethoxam induced the highest mortality of the 3 insecticides, and dinotefuran was the least toxic.CONCLUSIONIf the time needed to achieve effective thresholds of a systemic neonicotinoid is known, treatments at production facilities could be scheduled that would minimize unnecessary post-treatment holding periods and ensure maximum retention of effective concentrations after the plants have shipped to retail outlets. The rapid uptake of the insecticides and retention at effective concentrations in containerized citrus suggest that the current 30-day post-treatment shipping restriction from production facilities to retail outlets outside of quarantine could be shortened to 14 days. Thiamethoxam should be added to the list of approved nursery treatments.
      PubDate: 2016-10-07T02:30:47.953007-05:
      DOI: 10.1002/ps.4451
  • Insecticide Resistance, Control Failure Likelihood, & the First Law of
    • Authors: Raul Narciso C Guedes
      Abstract: Insecticide resistance is a broadly recognized ecological backlash resulting from insecticide use and is widely reported among arthropod pest species with well-recognized underlying mechanisms and consequences. Nonetheless, insecticide resistance is the subject of evolving conceptual views that introduces a different concept useful if recognized in its own right—the risk or likelihood of control failure. Here we suggest an experimental approach to assess the likelihood of control failure of an insecticide allowing for consistent decision-making regarding management of insecticide resistance. We also challenge the current emphasis on limited spatial sampling of arthropod populations for resistance diagnosis in favor of comprehensive spatial sampling. This necessarily requires larger population sampling—aiming to use spatial analysis in area-wide surveys—to recognize focal points of insecticide resistance and/or control failure that will better direct management efforts. The continuous geographical scale of such surveys will depend on the arthropod pest species, pattern of insecticide use, and many other potential factors. Regardless, distance-dependence among sampling sites should still hold, following the maxim that the closer two things are, the more they resemble each other, which is the basis of Tobler's First Law of Geography.
      PubDate: 2016-10-07T02:11:26.837899-05:
      DOI: 10.1002/ps.4452
  • Sensitivity of Fusarium culmorum to triazoles: impact of trichothecene
           chemotypes, oxidative stress response and genetic diversity
    • Authors: Pierre Hellin; Jonathan Scauflaire, Viviane Van Hese, Françoise Munaut, Anne Legrève
      Abstract: BACKGROUNDFusarium culmorum is a fungal pathogen occurring worldwide on various weeds and important crops. Triazoles have been shown to be the most effective fungicide for managing Fusarium spp. but little is known about their specific activity on F. culmorum.RESULTSThe sensitivity of 107 F. culmorum strains to triazoles was assessed using microtiter plate assays. The EC50 values ranged from 0.14 to 1.53 mg L −1 for tebuconazole and from 0.25 to 2.47 mg L −1 for epoxiconazole. High cross-resistance to both azoles was found (r = 0.61). Fusarium culmorum appeared to be significantly more sensitive than F. graminearum or F. cerealis. No increase in the mean EC50 was observed over time, which might be related to an unfavorable fitness cost, measured here as fungal growth. On average, nivalenol-producing strains of F. culmorum were significantly more resistant than deoxynivalenol-producing strains. The relationship between resistance and chemotype-dependent adaptation to oxidative stress was investigated, but remained unclear. No link between inter-simple sequence repeat (ISSR) genetic diversity and triazole resistance could be established.CONCLUSIONFungicide use might not be a driving force in the evolution of F. culmorum and the benefit of a resistance trait probably does not outweigh its costs.
      PubDate: 2016-10-03T10:55:30.801352-05:
      DOI: 10.1002/ps.4450
  • Synergistic mortality between a neonicotinoid insecticide and an
           ergosterol-biosynthesis-inhibiting fungicide in three bee species
    • Authors: Fabio Sgolastra; Piotr Medrzycki, Laura Bortolotti, Maria Teresa Renzi, Simone Tosi, Gherardo Bogo, Dariusz Teper, Claudio Porrini, Roberto Molowny-Horas, Jordi Bosch
      Abstract: BACKGROUNDNeonicotinoid insecticides have been identified as an important factor contributing to bee diversity declines. Nonetheless, uncertainties remain about their impact under field conditions. Most studies have been conducted on Apis mellifera and tested single compounds. However, in agricultural environments, bees are often exposed to multiple pesticides. We explore synergistic mortality between a neonicotinoid (clothianidin) and an ergosterol-biosynthesis-inhibitor fungicide (propiconazole) in three bee species (A. mellifera, Bombus terrestris, Osmia bicornis) following oral exposure in the laboratory.RESULTSWe developed a new approach based on the binomial proportion test to analyze synergistic interactions. We estimated uptake of clothianidin per foraging bout in honey bees foraging on seed-coated rapeseed fields. We found significant synergistic mortality in all three bee species exposed to non-lethal doses of propiconazole and their respective LD10 of clothianidin. Significant synergism was only found in the first assessment times in A. mellifera (4 and 24 h) and B. terrestris (4 h), but persisted throughout the experiment (96 h) in O. bicornis. Osmia bicornis was also the most sensitive species to clothianidin.CONCLUSIONOur results underscore the importance to test pesticide combinations likely to occur in agricultural environments, and to include several bee species in environmental risk assessment schemes.
      PubDate: 2016-09-29T10:16:27.217387-05:
      DOI: 10.1002/ps.4449
  • Establishment of in vitro soybean aphids, Aphis glycines (Hemiptera:
           Aphididae): a tool to facilitate studies of aphid symbionts, plant-insect
           interactions and insecticide efficacy
    • Authors: Andika Gunadi; Raman Bansal, John J Finer, Andy Michel
      Abstract: BACKGROUNDStudies on plant-insect interactions of the soybean aphid, Aphis glycines (Matsumura), can be influenced by environmental fluctuations, status of the host plant and variability in microbial populations. Maintenance of aphids on in vitro-grown plants minimizes environmental fluctuations, provides uniform host materials and permits the selective elimination of aphid-associated microbes for more standardized controls in aphid research.RESULTSAphids were reared on sterile, in vitro-grown soybean seedlings, germinated on plant tissue culture media amended with a mixture of antimicrobials. For initiation and maintenance of in vitro aphid colonies, single aphids were inoculated onto single in vitro seedlings. After 3 rounds of transfer of “clean” aphids to fresh in vitro seedlings, contamination was no longer observed, and aphids performed equally well when compared to those reared on detached leaves. Addition of the insecticides thiamethoxam and chlorantraniliprole to the culture medium confirmed uptake and caused significant mortality to the in vitro aphids. The use of the antimicrobial mixture removed the associated bacteria Arsenophonus but retained Buchnera and Wolbachia within the in vitro aphids.CONCLUSIONThe in vitro aphid system is a novel and highly useful tool to understand insecticidal efficacy and expand our knowledge of tri-trophic interactions among plants, insects and symbionts.
      PubDate: 2016-09-28T09:03:17.002205-05:
      DOI: 10.1002/ps.4448
  • No effect of Bt-transgenic rice litter on meiobenthos community in field
    • Authors: Yongbo Liu; Wanxiang Jiang, Yuyong Liang, Caiyun Zhao, Junsheng Li
      Abstract: BACKGROUNDThe non-target effect of Bacillus thuringiensis (Bt) toxins in aquatic ecosystems is crucial to improve the present assessment of Bt-transgenic plants, particularly where crops are cultivated near aquatic ecosystems. We conducted decomposition experiments during two growing seasons to determine the effects of Bacillus thuringiensis (Bt)-transgenic rice litter with and without insecticide application on meiobenthos communities in a field ditch.RESULTSCommunity composition of meiobenthos colonized on leaf litter was not significantly different between Bt and non-Bt rice. Abundance of meiobenthos colonizing leaves differed between insecticide application and control, and this insecticide effect was interacted with rice type. No Bt toxin was detected in the field ditch water. Leaf decomposition and nutrient content were comparable for both Bt and non-Bt rice with or without insecticide application.CONCLUSIONBt-transgenic rice litter had no effect on meiobenthos community composition in field ditches, but the chronic persistence of transgenic litter in nature needs to be taken into account at large scales in aquatic ecosystems.
      PubDate: 2016-09-22T08:40:22.76349-05:0
      DOI: 10.1002/ps.4446
  • Biological control potential of entomopathogenic nematodes for management
           of Caribbean fruit fly, Anastrepha suspensa Loew (Tephritidae)
    • Authors: William K. Heve; Fahiem E. El‐Borai, Daniel Carrillo, Larry W. Duncan
      Abstract: BACKGROUNDCaribbean fruit fly (Caribfly) is a serious economic insect pest because of development of larvae that hatch from eggs oviposited into fruits by female adults. This study assessed virulence of at least 10 entomopathogenic nematodes (EPNs) to Caribfly in laboratory bioassays as a starting point toward evaluation of management strategies for the fruit‐to‐soil‐dwelling stages of A. suspensa in fields infested by Caribfly.RESULTSInoculation of A. suspensa with 1 ml of ca. 200 IJs (larva)−1 killed Caribfly at either larval or pupal stage. Pupae were more resistant to EPN infections than larvae. Adult emergence from inoculated pupae in soil microcosms was significantly lower than those observed in filter paper assays. Longest or largest steinernematids suppressed emergence of more adult Caribfly from pupae in soils whereas shorter heterorhabditids were more infectious to Caribfly larvae. The highest mortalities of A. suspensa were caused by exotic nematodes Steinernema feltiae and Heterorhabditis bacteriophora followed by the native Heterorhabditis indica and the exotic Steinernema carpocapsae.CONCLUSIONEntomopathogenic nematodes reduced development of Caribfly larvae and pupae to adult in our bioassays, suggesting that EPNs have potential for biological control of A. suspensa. Future work will assess management strategies, using the virulent EPNs, in orchards infested by A. suspensa.
      PubDate: 2016-09-22T08:35:22.025783-05:
      DOI: 10.1002/ps.4447
  • Molecular characterization of two α‐esterase genes involving
           chlorpyrifos detoxification in the diamondback moth, Plutella xylostella
    • Authors: Miao Xie; Na‐Na Ren, Yan‐Chun You, Wei‐Jun Chen, Qi‐Sheng Song, Min‐Sheng You
      Abstract: BACKGROUNDCarboxylesterases (CarEs) are involved in metabolic detoxification of dietary and environmental xenobiotics in insects. However, due to the complexity of the protein family, the involvement of CarEs in insecticide metabolism in Plutella xylostella has not been fully elucidated. This study aimed to characterize two CarE genes and assess their potential roles in response to chlorpyrifos in P. xylostella.RESULTSSynergistic test showed that triphenyl phosphate decreased the resistance of the 3rd‐instar larvae to chlorpyrifos. The treatment of the 3rd‐instar larvae with chlorpyrifos at the dose of LC30 led to significant increase of CarE activity. Two CarE cDNAs (Pxae18 and Pxae28) were subsequently sequenced and characterized. Both genes were expressed predominantly in larva midgut. Most importantly, two CarE genes showed significantly higher expression in the chlorpyrifos resistant strain (CRS) than in the susceptible strain (SS). RNAi knockdown of Pxae18 and Pxae28 significantly increased the mortality to chlorpyrifos from 40% in control to 73.8% and 63.3%, respectively.CONCLUSIONRNAi knockdown of Pxae18 and Pxae28 significantly inhibited the detoxification ability, and increased the mortality in P. xylostella. The results indicate that these two CarE genes play important roles in detoxification of chlorpyrifos in P. xylostella.
      PubDate: 2016-09-22T08:31:15.471615-05:
      DOI: 10.1002/ps.4445
  • A potential IGR for cockroach control: design, synthesis and bioactivity
           of N‐terminal modified allatostatin analogs
    • Authors: Xiaoqing Wu; Meizi Wang, Juan Huang, Li Zhang, Zhe Zhang, Yun Ling, Xinling Yang, Stephen S. Tobe
      Abstract: BACKGROUNDThe FGLa‐allatostatins (ASTs) are a family of neuropeptides that can inhibit juvenile hormone biosynthesis by the corpora allata (CA) in vitro, and therefore, they are regarded as insect growth regulator (IGR) candidates for pest control. In our previous studies, an AST mimic, H17 was found to have a significant effect on JH biosynthesis by cockroach CA, both in vitro and in vivo. To discover new potential mimics and explore the substituent effect on the inhibition of JH biosynthesis, 30 analogs, modified with various substituents on the benzene ring at the N‐terminus of lead compound H17, were designed and synthesized. Their bioactivity in inhibiting JH biosynthesis by the CA of Diploptera punctata and the potency of M9, M10 and M11 in activation of Dippu‐AstR was evaluated.RESULTSAll the analogs showed an effect on JH biosynthesis by CA in vitro. M9, M10 and M11 can activate the Dippu‐AstR, albeit with much lower potency than that of AST 1. M11 also exhibited improved in vitro activity (IC50: 6.98 nmol/L) in comparison with the lead compound H17 (IC50: 29.5 nmol/L). In particular, M11 displayed good in vivo activity in inhibiting JH biosynthesis and basal oocyte growth.CONCLUSIONThe structure‐activity relationship (SAR) studies suggest that different positions of substituents on the benzene ring of the cinnamic acid can lead to different activities. The para‐substitution on the benzene ring plays an important role in inhibiting JH biosynthesis in vitro. Moreover, M11 is considered to be a potential IGR for cockroach control.
      PubDate: 2016-09-22T08:31:06.964895-05:
      DOI: 10.1002/ps.4444
  • Characterisation of Ramularia collo‐cygni laboratory mutants resistant
           to Succinate Dehydrogenase Inhibitors
    • Authors: Marta J Piotrowska; James M Fountaine, Richard A Ennos, Maciej Kaczmarek, Fiona J Burnett
      Abstract: BACKGROUNDRamularia collo‐cygni (Rcc) is responsible for Ramularia leaf spot (RLS), a foliar disease of barley contributing to serious economic losses. Protection against the disease has been almost exclusively based on fungicide applications, including Succinate Dehydrogenase Inhibitors (SDHIs). In 2015 the first field isolates of Rcc with reduced sensitivity to SDHIs were recorded in some European countries. In this study we established baseline sensitivity of Rcc to SDHIs in the UK and characterised mutations correlating with resistance to SDHIs in UV‐generated mutants.RESULTSFive SDHI resistant isolates were generated by UV mutagenesis. In four of these mutants a single amino acid change in a target succinate dehydrogenase (Sdh) protein was associated with decrease in sensitivity to SDHIs. Three of these mutations were stably inherited in the absence of SDHI fungicide and resistant isolates did not demonstrate a fitness penalty. There were no detectable declines in sensitivity in field populations in years 2010–2012 in the UK.CONCLUSIONSSDHIs remained effective in controlling Rcc in the UK in years 2010–2012. However given that the first isolates of Rcc with reduced sensitivity appeared in other European countries in 2015, robust anti‐resistance strategies need to be continuously implemented to maintain effective disease control.
      PubDate: 2016-09-19T09:50:32.905348-05:
      DOI: 10.1002/ps.4442
  • Overexpression of TAT‐PTD‐diapause hormone fusion protein in tobacco
           and it effect on larval development of Helicoverpa armigera (Lepidoptera:
    • Authors: Zhou Zhou; Yongli Li, Chunyan Yuan, Daniel Doucet, Yongan Zhang, Liangjian Qu
      Abstract: BACKGROUNDThe diapause hormone (DH) has been shown to either induce or terminate diapause depending on the insect species. In a previous study we demonstrated that the DH from Clostera anastomosis (caDH) has biological activity in Helicoverpa armigera, which prompted us to examine the potential growth‐inhibiting or antiherbivory effects of the TAT‐caDH fusion protein when expressed in transgenic plants.RESULTSIn this study, we produced transgenic tobacco plants expressing either the TAT‐caDH protein, or a TAT‐caDH‐eGFP fusion version that allows tracking of the fluorescent protein in plant tissues. Our results indicate that H. armigera larvae feeding on transgenic tobacco expressing TAT‐caDH exhibited a significantly reduced survival rate and weight gain. However, larvae feeding on transgenic tobacco expressing TAT‐caDH‐eGFP were unaffected. While fusion of the eGFP gene influenced the bioactivity of caDH in larvae, TAT‐caDH‐eGFP can still penetrate the insect midgut cell membrane.CONCLUSIONTAT‐caDH increases DH stability in oral delivery. Our results may help in targeting DH‐dependent physiological processes in insects for improving herbivore tolerance in economically important crops.
      PubDate: 2016-09-19T09:40:20.718787-05:
      DOI: 10.1002/ps.4443
  • Phorate can reverse P450 metabolism‐based herbicide resistance in
           Lolium rigidum
    • Authors: Roberto Busi; Todd Adam Gaines, Stephen Powles
      Abstract: BACKGROUNDOrgano‐phosphate insecticides can inhibit specific cytochrome P450 enzymes involved in metabolic herbicide resistance mechanisms leading to synergistic interactions between the insecticide and the herbicide. In this study we report synergistic versus antagonistic interactions between the organo‐phosphate insecticide phorate and five different herbicides observed in a population of multiple herbicide‐resistant Lolium rigidum.RESULTSPhorate synergized with three different herbicide modes of action enhancing the activity of the ALS‐inhibitor chlorsulfuron (60% LD50 reduction), the VLCFAE‐inhibitor pyroxasulfone (40% LD50 reduction), and the mitosis‐inhibitor trifluralin (70% LD50 reduction). Conversely, phorate antagonized the two thiocarbamate herbicides prosulfocarb (7‐fold LD50 increase) and triallate (11‐fold LD50 increase).CONCLUSIONWe report the selective reversal of P450‐mediated metabolic multiple‐resistance to chlorsulfuron and trifluralin in the grass weed L. rigidum by synergistic interaction with the insecticide phorate and discuss the putative mechanistic basis. This research should encourage diversity in herbicide use patterns for weed control as part of a long‐term integrated management effort to reduce the risk of selection of metabolism‐based multiple herbicide resistance in L. rigidum.
      PubDate: 2016-09-19T09:35:22.019313-05:
      DOI: 10.1002/ps.4441
  • Substitutions in Spodoptera exigua Topoisomerase I modulate its relaxation
           activity and camptothecin sensitivity
    • Authors: Pei Zhang; Lan Zhang, Yanning Zhang, Liangang Mao, Hongyun Jiang
      Abstract: BACKGROUNDTopoisomerase I (Top I) is referred as the cellular target of the camptothecins (CPTs) which are now being explored as potential pesticides for insect control. Three amino acid substitutions including L530P, A653T and S729T in Top Is of insects were found in our previous studies. In order to investigate the effect of these three substitutions, the comparative analysis was conducted between the wild type and mutant Top Is in Spodoptera exigua Hübner.RESULTSThe optimal salt concentration of A653T and S729T was 150 mM consistent with that of the wild type Top I. While, the mutant L530P showed the maximum relaxation activity at a lower KCl concentration (100 mM). The mutated L530P and A653T Top Is showed higher relaxation efficiency due to the increased relaxation velocity toward the negatively supercoiled plasmid pBR322 DNA, which rendered L530P and A653T resistance to CPTs. While, mutant S729T exhibited sensitivity to CPTs as a result of a decreased relaxation activity toward plasmid pBR322 DNA.CONCLUSIONSThese results suggested that the polymorphism in Top I of insects was related to the biological activity of CPTs, which provided the basic information for the reasonable usage of CPTs to control insect pests.
      PubDate: 2016-09-19T09:29:40.022106-05:
      DOI: 10.1002/ps.4440
  • Inhibition of early development stages of rust fungi by the two fungal
           metabolites cyclopaldic acid and epi‐epoformin
    • Authors: Eleonora Barilli; Alessio Cimmino, Marco Masi, Marco Evidente, Diego Rubiales, Antonio Evidente
      Abstract: BACKGROUNDRusts are a noxious group of plant diseases affecting major economically important crops. Crop protection is largely based on chemical control. There is a renewed interest in the discovery of natural products as alternatives to synthetic fungicides for control. In this study we tested two fungal metabolites, namely cyclopaldic acid and epi‐epoformin, for their effectiveness in reducing early stages of development of two major rusts fungi from the genera Puccinia and Uromyces, P. triticina and U. pisi. Spore germination and appressoria formation were assessed on pre‐treated detached leaves under controlled conditions. Cyclopaldic acid and epi‐epofomin were also tested in infected plants in order to evaluate the level of control achieved by treatments both before and after inoculation.RESULTSCyclopaldic acid and epi‐epoformin were strongly effective in inhibiting fungal germination and penetration of both rust species studied. This effect was not dose‐dependent. These results were further confirmed in planta by spraying the metabolites on plants leaves which reduced fungal developmental of U. pisi and P. triticina at values comparable to those obtained by application of the fungicide.CONCLUSIONOur results further demonstrate the potential of fungal metabolites as natural alternatives to synthetic fungicides for the control of crop pathogens of economic importance as rusts.
      PubDate: 2016-09-14T04:05:42.680358-05:
      DOI: 10.1002/ps.4438
  • Insecticide resistance and size assortative mating in females of the maize
           weevil (Sitophilus zeamais)
    • Authors: Erick Mauricio G Cordeiro; Alberto S Corrêa, Conrado A Rosi‐Denadai, Hudson Vaner V Tomé, Raul Narciso C Guedes
      Abstract: BACKGROUNDRandom mating is a common assumption in studies of insecticide resistance evolution, but seldom tested despite its potential consequences. Therefore, the existing evidence of female choice and insecticide resistance in populations of the maize weevil (Sitophilus zeamais), a key pest of stored cereals, led to the assessment of mating preferences and its association with insecticide resistance in this species.RESULTSMixed lines of a maize weevil colony were established from field‐collected populations, which after five months of natural breeding were selected for deltamethrin resistance for five generations reaching over 100‐fold resistance. Mating preference was significantly based on the partner size, measured as body mass (χ2 = 5.83, df = 1, P = 0.016). Susceptible females preferred heavier males for mating (χ2 = 5.83, df = 1, P = 0.015), trait that was more frequently associated with deltamethrin resistance (χ2 = 7.38, df = 1, P = 0.007). Deltamethrin resistance compromised daily fertility, although the reduced offspring production observed in matings between susceptible females and resistant males were negligible.CONCLUSIONSusceptible female weevils prefer larger (and heavier) males to mate, trait associated with deltamethrin resistance, favoring the maintenance and spread of the resistant phenotype in the population.
      PubDate: 2016-09-14T03:55:31.426955-05:
      DOI: 10.1002/ps.4437
  • Monitoring and mechanisms of insecticide resistance in Chilo suppressalis
           (Lepidoptera: Crambidae) with special reference to diamides
    • Authors: Rong Yao; Dan‐Dan Zhao, Shuai Zhang, Li‐Qi Zhou, Xin Wang, Cong‐Fen Gao, Shun‐Fan Wu
      Abstract: BACKGROUNDThe rice stem borer, Chilo suppressalis Walker (Lepidoptera: Crambidae) is one of the most economically important pests of rice in Asia. Chemical control remains the most efficient primary means for controlling this pest.RESULTSSignificant variations among field populations to seven insecticides were observed. The populations exhibited LC50 values that ranged between 0.605 ‐ 108.088 mg a.i L−1 for chlorantraniliprole and 0.046 ‐ 3.919 mg a.i L−1 for flubendiamide. YY14 population collected from Yuyao in Zhejiang province at 2014 showed moderate resistance level to two diamides, i.e., up to 77.6‐ and 42.6‐fold for chlorantraniliprole and flubendiamide, respectively. Synergism tests and biochemical assays showed no obvious correlations between diamides resistance and three detoxifying enzymes. Sequence comparison of ryanodine receptor gene between YY14 resistant population and susceptible population revealed that a glycine to glutamic acid substitution (G4910E) was presented in the YY14 population.CONCLUSIONG4910E mutation might be involved in the resistance evolution of C. suppressalis to the diamides. The appropriate insecticide resistance management program should be established to maintain the effectiveness of the insecticides and to ensure sustainable management.
      PubDate: 2016-09-14T03:47:18.459542-05:
      DOI: 10.1002/ps.4439
  • A negative association between bromadiolone exposure and nestling body
           condition in common kestrels: management implications for vole outbreaks
    • Authors: J. Martínez‐Padilla; D. López‐Idiáquez, J.J. López‐Perea, R. Mateo, A. Paz, J. Viñuela
      Abstract: BACKGROUNDVole outbreaks have been extensively described along with their impacts on humans, particularly in agricultural areas. The use of rodenticides is a common legal practice to minimise crop damage induced by high vole density for biocidal use. However, rodenticides can have negative direct and indirect impacts on non‐target species that feed on voles. We studied whether the use of a second generation anticoagulant rodenticide, bromadiolone, can be detected in the blood of fledglings of wild common kestrels Falco tinnunculus in two areas of central Spain, exploring its possible indirect effects.RESULTSWe found that 16.9% of fledgling had detectable concentration of bromadiolone in their blood, with an average concentration of 0.248 ± 0.023 ng/mL. Fledglings with bromadiolone in their blood, regardless of the concentration, had 6.7% lower body mass than those without detectable bromadiolone.CONCLUSIONThe use of bromadiolone was detectable in the blood of alive non‐target species. Detected bromadiolone in blood may reduce body condition of nestlings, potentially reducing their fitness. The source of bromadiolone found in nestlings need to be determined in future studies to derive accurate management advice. However, we urge the discontinuation of official SGAR distribution to farmers and their use in agrarian lands to minimise damage of voles on crops, particularly where common kestrel breed and encourage the use of alternative effective practices.
      PubDate: 2016-09-12T04:55:28.009228-05:
      DOI: 10.1002/ps.4435
  • Detection of the cytochrome b mutation G143A in Irish Rhynchosporium
           commune populations using targeted 454 sequencing
    • Authors: Sinead Phelan; Marie‐Sophie Barthe, Camille Tobie, Steven Kildea
      Abstract: BACKGROUNDRhynchosporium commune is a major fungal pathogen of barley crops and the application of fungicides, such as Quinone outside inhibitors (QoI’s), plays an important role in crop disease control. The genetic mechanisms linked to QoI resistance have been identified in the cytochrome b gene, with QoI resistance conferred by the G143A substitution. The objective of this study was to develop a high throughput molecular assay to detect and identify mutations associated with QoI resistance within the Irish R. commune population.RESULTSLeaf lesions of R. commune sampled from 74 sites, during 2009‐2014, and isolates from 2006 and 2007 were screened for non‐synonymous mutations of the cytochrome b gene using 454 targeted sequencing. The presence of the G143A substitution was confirmed in R. commune samples in one site in 2013 and in four sites in 2014, however the frequency of the substitution in these samples was low (2‐18%). 454 sequencing results were confirmed though PCR‐RFLP and Sanger sequencing.CONCLUSIONThe molecular assay which has been applied to this monitoring programme has shown that the application of 454 next generation sequencing offers the potential for high throughput and accurate characterisation of non‐synonymous mutations associated with fungicide resistance in a crop pathogen.
      PubDate: 2016-09-12T04:06:08.607765-05:
      DOI: 10.1002/ps.4434
  • Evaluation of field resistance to Striga hermonthica [Del.] Benth. in
           Sorghum bicolor [L.] Moench. The relationship with strigolactones
    • Authors: Nasreldin M. Ahmed; Tatsiana Charnikhova, Evert J. Bakker, Aad van Ast, Abdelgabar G.T. Babiker, Harro J. Bouwmeester
      Abstract: BACKGROUNDSignificant losses in sorghum biomass and grain yield occur in sub‐Saharan Africa due to infection by the root parasitic weed Striga hermonthica [Del.] Benth. One strategy to avoid these losses is to adopt resistant crop varieties. To further delineate the role of germination stimulants in resistance we conducted a field experiment employing six sorghum genotypes, in eastern Sudan, and in parallel analysed the strigolactone levels in the root exudates of these genotypes under controlled conditions in Wageningen.RESULTSThe root exudates of these genotypes displayed large differences in strigolactone composition and Striga germination inducing activity. Korokollow, Fakimustahi and Wadfahel exuded the highest amounts of 5‐deoxystrigol. Fakimustahi was by far the highest sorgomol producer and Wadbaco and SRN39 produced the highest amount of orobanchol. The concentration of 5‐deoxystrigol in the root exudate showed a significant positive correlation with in vitro Striga germination and was positively associated with Striga infection in the field experiments, while orobanchol, on the other hand, was negatively associated with Striga infection in the field experiments.CONCLUSIONFor the first time a close association is reported between strigolactone levels, analysed under laboratory conditions, and Striga infection in the field in sorghum genotypes. These genotypes may be used to further study this resistance mechanism and for the introgression of the low germination trait in other sorghum varieties to breed for a strigolactone composition with low stimulant activity. The use of such improved varieties in combination with other Striga management tools could possibly alleviate the current Striga problem in the African continent.
      PubDate: 2016-09-09T07:17:16.014851-05:
      DOI: 10.1002/ps.4426
    • Authors: Rafael M Tavares; João P A R Cunha, Thales C Alves, Mariana R Bueno, Sérgio M Silva, César H S Zandonadi
      Abstract: BACKGROUNDDue to the difficulty in reaching targets during pesticide applications on guava trees, it is important to evaluate new technologies that may improve pest management. In electrostatic spraying, an electric force is added to the droplets to control their movements such that they are efficiently directed to the target. The present study evaluated the performance of electrostatic and non‐electrostatic spraying in the control of the guava psyllid, the deposition of the spray mixture on the leaves, and the losses to the soil.RESULTSThe deposition of the spray mixture was up to two times greater when using electrostatic spraying in comparison with non‐electrostatic application. The losses of the spray mixture to the soil were up to four times smaller with the electrostatic spraying. Electrostatic had better control of the psyllid.CONCLUSIONIt was possible to reduce the volume rate of application with electrostatic spraying without adversely affecting the control of the guava psyllid.
      PubDate: 2016-09-08T08:45:45.603231-05:
      DOI: 10.1002/ps.4433
  • Active saponins from root of Pueraria peduncularis (Grah. ex Benth.)
           Benth. and their molluscicidal effects on Pomacea canaliculata
    • Authors: ChunPing Yang; Min Zhang, Bo Lei, GuoShu Gong, GuiZhou Yue, XiaoLi Chang, XiaoFang Sun, Yue Tian, HuaBao Chen
      Abstract: BACKGROUNDPueraria peduncularis (Grah. ex Benth.) Benth., which belongs to the Leguminosae family, exhibits resistance to many crop pests in agricultural production. Pomacea canaliculata is an important invasive snail in rice fields and causes severe yield losses. To evaluate the toxicity of P. peduncularis to P. canaliculata, in this study, the molluscicidal activity of root extracts of P. peduncularis was tested against P. canaliculata, and the active compounds were isolated, and the structures of these compounds were analyzed on the basis of using nuclear magnetic resonance (NMR) analysis and mass spectral analysis.RESULTSOur results showed that the molluscicidal activity of the root crude extract differed between P. canaliculata with different shell diameters after treatment for 72 h. The median lethal concentration (LC50) was 5.511 mg · L−1 against snails with1.5 ± 0.2 cm in diameter and 12.383 mg · L−1 against snails with 2.5 ± 0.2 cm in diameter. Furthermore, two active ingredients isolated from root methanol extracts were identified as pedunsaponin A and pedunsaponin C. Both pedunsaponin A and C showed strong molluscicidal activities, with LC50 values of 3.893 mg · L−1 and 4.252 mg · L−1, respectively, against snails with shell diameters of 1.5 ± 0.2 cm after treatment for 72 h.CONCLUSIONPueraria peduncularis extracts exhibit high molluscicidal activity and have great potential value for exploring a molluscicide to control Pomacea canaliculata.
      PubDate: 2016-09-08T08:45:42.622886-05:
      DOI: 10.1002/ps.4432
  • Discovery of the aryl heterocyclic amine (AHA) insecticides: Synthesis,
           insecticidal activity, field results, mode of action and bioavailability
           of a leading field candidate
    • Authors: William H Dent; Mark A Pobanz, Chaoxian Geng, Thomas C Sparks, Gerald B Watson, Theodore J Letherer, Kenneth W Beavers, Cathy D Young, Yelena A Adelfinskaya, Ronald R Ross, Greg Whiteker, James Renga
      Abstract: BACKGROUNDGamma‐amino butyric acid (GABA) antagonists are proven targets for control of Lepidopteran and other pests. New heterocyclic compounds with high insecticidal activity were discovered using a competitive‐intelligence inspired scaffold hopping approach to generate analogs of fipronil, a known GABA antagonist. These novel aryl heterocyclic amines (AHA’s) displayed broad spectrum activity on a number of chewing insect pests.RESULTSThrough >370 modifications of the core AHA structure, a 7‐pyrazolopyridine lead molecule was found to exhibit much improved activity on a number of insect pests. In field trial studies, its performance was 2 – 4x lower than commercial standards and also appeared to be species dependent with good activity seen for larvae of Spodoptera exigua, but inactive on larvae of Trichoplusia ni.CONCLUSIONAn extensive investigational biology effort demonstrated that these AHA analogs appear to have multiple modes of action including GABA receptor antagonism and mitopotential or uncoupler activity. The limited capability in larvae of T. ni to convert the lead molecule to its associated open form correlates with the low toxicity of the lead molecule in this species. This work has provided information that could aid investigations of novel GABA antagonists.
      PubDate: 2016-09-08T08:25:19.649081-05:
      DOI: 10.1002/ps.4431
  • Biological activity of Myrtaceae plant essential oils and their major
           components against Drosophila suzukii (Diptera: Drosophilidae)
    • Authors: Miyeon Jang; Junheon Kim, Kyungjae Andrew Yoon, Si Hyeock Lee, Chung Gyoo Park
      Abstract: BackgroundThe spotted wing drosophila (SWD), Drosophila suzukii (Matsumura), is a globally invasive and serious pest of numerous soft‐skinned fruit crops. Assessments were made of fumigant and contact toxicities of 12 Myrtaceae plant essential oils (EOs) and their components. For determining the mode of action of major components of active EOs, their activities against acetylcholinesterase (AChE) and Glutathione S‐transferase (GST) were also assessed.ResultsStrong fumigant and contact toxicities were observed from EOs of Eucalyptus citriodora and Melaleuca teretifolia. The main components of E. citriodora were citronellal and isopulegol, whereas those of M. teretifolia were neral and geranial. Geranial showed the strongest fumigant activity followed by citronellal or neral, M. teretifolia EO, isopulegol, and E. citriodora EO. In contact toxicity assay, Geranial also exhibited the strongest insecticidal activity followed by neral or M. teretifolia EO, citronellol, citronellal, isopulegol, and E. citriodora EO. Among the major components, all compounds showed low AChE inhibitory activity, while neral and geranial showed GST inhibitory activity against SWD.ConclusionMyrtaceae plant EOs and their components have an excellent potential for being used in the control of SWD adult and could be useful in the development of more effective natural compounds as alternatives to synthetic pesticides.
      PubDate: 2016-09-08T07:35:41.348074-05:
      DOI: 10.1002/ps.4430
  • Impact of sesquiterpenes from Inula racemosa (Asteraceae) on growth,
           development and nutrition of Spodoptera litura (Lepidoptera:Noctuidae)
    • Authors: Mandeep Kaur; Rakesh Kumar, Deep Patel Upendrabhai, Inder Pal Singh, Sanehdeep Kaur
      Abstract: BACKGROUNDThe use of botanical pesticides for protecting crops from insect pests has assumed greater importance all over the world due to growing awareness of harmful effects of indiscriminate use of synthetic pesticides. Inula racemosa Hook. f. (Asteraceae), a medicinally important perennial herb is rich in sesquiterpenes with many biological activities. The present studies were conducted with the objective to evaluate the sesquiterpenes isolated from I. racemosa for insecticidal activity against Spodoptera litura (F.).RESULTSAlantolactone and isoalantolactone isolated from I. racemosa, exerted growth inhibitory effects on S. litura. Addition of both the sesquiterpenes to larval diet extended the development period and reduced pupation as well as adult emergence. The dietary utilization experiments on 3rd instar larvae of S. litura revealed reduction in consumption and growth rates of larvae as well as efficiency of conversion of ingested and digested food due to alantolactone and isoalantolactone.CONCLUSIONThe root extract of I. racemosa which is rich in two sesquiterpenes i.e. alantolactone and isoalantolactone, has the potential for management of S. litura. However, there is need to understand the specific mechanism of action of these compounds.
      PubDate: 2016-09-08T07:31:16.575324-05:
      DOI: 10.1002/ps.4429
  • Evaluating a filtering and recirculating system to reduce dust drift in
           simulated sowing of dressed seed and abraded dust particle characteristics
    • Authors: Marcello Biocca; Daniele Pochi, Roberto Fanigliulo, Pietro Gallo, Patrizio Pulcini, Francesca Marcovecchio, Cinzia Perrino
      Abstract: BACKGROUNDThe pneumatic precision drills used in maize sowing can release dust due to abrasion of dressed seed; the drift of dust containing insecticide active ingredients (a.i.) are harmful to honeybees. Therefore, we developed a device for drills, which uses partial recirculation and filtration of the air by means of an anti‐pollen and an electrostatic filter.RESULTSTests were carried out by simulating sowing of seed treated with imidacloprid, thiamethoxam, clothianidin and fipronil. Dust released by the drill in different configurations were analyzed to assess its mass and a.i. concentration, size distribution and particle number concentration. In general, particles with a diameter lower than 2.5 µm (Particulate Matter ‐ PM2.5) and 10 µm (PM10), represent about 40% and 75% of the total dust mass, respectively. The finest size fraction (
      PubDate: 2016-09-08T07:31:14.403767-05:
      DOI: 10.1002/ps.4428
  • Companion planting with white yarrow or with feverfew for squash bug,
           Anasa tristis (Hemiptera: Coreidae) management on summer squash
    • Authors: Brian A. Kahn; Eric J. Rebek, Lynn P. Brandenberger, Keith Reed, Mark E. Payton
      Abstract: BACKGROUNDThe squash bug, Anasa tristis (De Geer) is a major insect pest of cucurbits. Control of squash bugs with insecticidal chemicals is difficult to achieve. We investigated the potential of companion planting with white yarrow (Achillea millefolium L.) or feverfew [Tanacetum parthenium (L.) Sch. Bip.] for squash bug management in field plantings of summer squash (Cucurbita pepo L.).RESULTSCompanion planting with white yarrow had few effects. Companion planting with feverfew tended to reduce squash bug populations, but results often were not statistically significant (P ≥ 0.05). Early‐season ventilated row covers (without herbs) neither reduced squash bug populations nor increased squash yields. Herbs reduced marketable squash yields compared with the control only once out of seven experiments.CONCLUSIONThe tested companion planting strategies inconsistently affected squash bug populations on summer squash. Therefore, these strategies are not recommended to commercial producers.
      PubDate: 2016-09-08T04:00:19.557072-05:
      DOI: 10.1002/ps.4427
  • How well will stacked transgenic pest/herbicide resistances delay pests
           from evolving resistance?
    • Authors: Jonathan Gressel; Aaron J. Gassmann, Micheal D. K. Owen
      Abstract: Resistance has evolved to single transgenic traits engineered into crops for arthropod and herbicide resistances, and can be expected to evolve to the more recently introduced pathogen resistances. Combining transgenes against the same target pest is being promoted as the solution to the problem. This solution would have worked if used pre‐emptively, but where resistance has evolved, resistance should easily evolve for the second gene in most cases. We propose and elaborate criteria that could be used to evaluate the value of stacked traits for pest resistance management. Stacked partners must: target the same pest species; be in a tandem construct to preclude segregation; be synchronously expressed in same tissues; have similar tissue persistence; target pest species that are still susceptible to at least two stacked partners. Additionally, transgene products must not be degraded in the same manner, and there should be a lack of cross‐resistance to stacked transgenes or to their products. With stacked herbicide resistance transgenes, both herbicides must be used and have the same persistence. If these criteria are followed, and integrated with other pest management practices, resistance may be considerably delayed.
      PubDate: 2016-09-06T09:00:40.298584-05:
      DOI: 10.1002/ps.4425
  • Value of Neonicotinoid Seed Treatments to US Soybean Farmers
    • Authors: Terry Hurley; Paul Mitchell
      Abstract: BACKGROUNDThe benefits of neonicotinoid seed treatment to soybean farmers have received increased scrutiny. Rather than use data from small‐plot experiments, this research uses survey data from 500 US farmers to estimate the benefit of neonicotinoid seed treatments to them. As seed treatment users, farmers are familiar with their benefits in the field and have economic incentives to only use them if they provide value.RESULTSOf the surveyed farmers, 51% used insecticide seed treatments, averaging 87% of their soybean area. Farmers indicated that human and environmental safety is an important consideration affecting their pest management decisions and reported aphids as the most managed and important soybean pest. Asking farmers who used seed treatments to state how much value they provided gives an estimate of US$28.04 ha−1 treated in 2013, net of seed treatment costs. Farmer reported average yields provided an estimated average yield gain of 128.0 kg ha−1 treated in 2013, or about US$42.20 ha−1 treated, net of seed treatment costs.CONCLUSIONThese estimates using different data and methods are consistent and suggest the value of insecticide seed treatments to the US soybean farmers that used them in 2013 was around US$28 to US$42 ha−1 treated, net of seed treatment costs.
      PubDate: 2016-08-30T23:20:23.534231-05:
      DOI: 10.1002/ps.4424
  • Identifying obstacles and ranking common biological control research
           priorities for Europe to manage most economically important pests in
           arable, vegetable and perennial crops
    • Authors: Jay Ram Lamichhane; Monika Bischoff‐Schaefer, Sylvia Bluemel, Silke Dachbrodt‐Saaydeh, Laure Dreux, Jean‐Pierre Jansen, Jozsef Kiss, Jürgen Köhl, Per Kudsk, Thibaut Malausa, Antoine Messéan, Philippe C. Nicot, Pierre Ricci, Jérôme Thibierge, François Villeneuve
      Abstract: BACKGROUNDEU agriculture is currently in transition from conventional crop protection to integrated pest management (IPM). Because biocontrol is a key component of IPM, many European countries recently have intensified their national efforts on biocontrol research and innovation (R&I) although such initiatives are often fragmented. The operational outputs of national efforts would benefit from closer collaboration among stakeholders via transnationally coordinated approaches since most economically important pests are similar across Europe.RESULTSThis paper proposes a common European framework on biocontrol R&I. It identifies generic R&I bottlenecks and needs as well as priorities for three crop types (arable, vegetable and perennial crops).CONCLUSIONSThe existing gap between the market offers of biocontrol solutions and the demand of growers, the lengthy and expensive registration process for biocontrol solutions and their varying effectiveness due to variable climatic conditions and site‐specific factors across Europe are key obstacles hindering the development and adoption of biocontrol solutions in Europe. Considering arable, vegetable and perennial crops, a dozen of common target pests are identified for each type of crop and ranked by order of importance at European level. Such a ranked list indicates numerous topics on which future joint transnational efforts would be justified.
      PubDate: 2016-08-28T23:35:36.243768-05:
      DOI: 10.1002/ps.4423
  • Evaluation of antifungal activities and structure‐activity relationships
           of Coumarin Derivatives
    • Authors: Ping‐Ping Song; Jun Zhao, Zong‐Liang Liu, Ya‐bing Duan, Yi‐ping Hou, Chun‐Qing Zhao, Min Wu, Min Wei, Nian‐he Wang, Ye Lv, Zhao‐Jun Han
      Abstract: BACKGROUNDOsthol is a natural coumarin and lead compound that has been developed into commercial fungicides in China. Natural coumarins comprise five major subtypes—simple coumarins, linear furanocoumarins, angular furanocoumarins, linear pyranocoumarins, and angular pyranocoumarins. Studies pertaining to the antifungal activities of linear pyranocoumarins are few, and no reports exist for the antifungal activities of angular pyranocoumarins. In order to discover more antifungal natural coumarins, we synthesized a series of simple natural coumarins and isolated several plant‐based furanocoumarins and pyranocoumarins using previously described methods. The compounds were biologically evaluated against some plant fungal pathogens.RESULTSSeveral of the 35 coumarins evaluated here exhibited strong activities against specific fungal species, including Compound 25 (Pd‐D‐V, a linear pyranocoumarin), Compound 26 (libanorin, an angular furanocoumarin), and Compound 34 (disenecioyl khellactone, an angular pyranocoumarin). Compound 25 exhibited a high activity against Sclerotinia sclerotiorum (EC50=13.2 µg·mL−1); Compound 34 displayed a strong antifungal activity against Botrytis cinerea (EC50=11.0 µg·mL−1).CONCLUSIONThis study demonstrates that several natural coumarins (one linear pyranocoumarin and one angular pyranocoumarin in particular) exhibit strong antifungal activities. These results compel further studies, where these coumarins can be examined as potential lead compounds for developing novel antifungal agents.
      PubDate: 2016-08-28T23:35:25.622971-05:
      DOI: 10.1002/ps.4422
  • Effect of nonwoven fabric covering on residual activity of pendimethalin
           in lettuce and soil
    • Authors: Miroslav Jursík; Jana Kováčová, Martin Kočárek, Kateřina Hamouzová, Josef Soukup
      Abstract: BACKGROUNDLettuce (Lactuca sativa L.) is a crop very sensitive to herbicide contamination due to its short growing season. Use of long‐residual herbicides and nonwoven fabric coverings could therefore influence pendimethalin concentrations in soil and lettuce.RESULTSPendimethalin half‐life in soil ranged between 18 and 85 days and was mainly affected by season (i.e., weather), especially by soil moisture. Pendimethalin degradation in soil was slowest under dry conditions. Longer pendimethalin half‐life was observed under the nonwoven fabric treatment, but the effect of varying application rate was not significant. Pendimethalin residue concentrations in lettuce heads were significantly influenced by pendimethalin application rate and by nonwoven fabric cover, especially at lettuce's early growth stages. The highest pendimethalin concentration at final harvest was determined in lettuce grown on uncovered plots treated by pendimethalin at application rate 1,200 g ha−1 (7–38 µg kg−1). Depending on growing season duration and weather conditions, pendimethalin concentrations in lettuce grown under nonwoven fabric ranged from 0 to 21 µg kg−1.CONCLUSIONUse of transparent nonwoven fabric cover with lettuce can help reduce application rates of soil herbicides and diminish the risk of herbicide contamination in the harvested vegetables.
      PubDate: 2016-08-25T03:46:10.492193-05:
      DOI: 10.1002/ps.4421
  • Bioassimilable Sulfur Provides Effective Control of Oidium neolycopersici
           in Tomato Enhancing Plant Immune System
    • Authors: Eugenio Llorens; Carlos Agustí‐Brisach, Ana I González‐Hernández, Pilar Troncho, Begonya Vicedo, Teresa Yuste, Marta Orero, Carlos Ledó, Pilar García‐Agustín, Leonor Lapeña
      Abstract: BACKGROUNDDevelopment of alternatives to the use of chemical pesticides to control pests are focused on the induction of natural plant defenses. The study of new compounds based on liquid bioassimilable sulfur and its effect as an inductor of the immune system of plants would provide an alternative option to farmers to enhance plant resistance against pathogen attacks such as powdery mildew. In order to elucidate the efficacy of this compound in tomato against powdery mildew, we tested several treatments: curative foliar, preventive foliar, preventive in soil drench and combining preventive in soil drench and curative foliar.RESULTSIn all cases, treated plants showed lower infection development, better physiological parameters and a higher level of chlorophyll. We also observed better performance in parameters involved in plant resistance such as antioxidant response, callose deposition and hormonal levels.CONCLUSIONThe results indicate that preventive and curative treatments can be highly effective for the prevention and control of powdery mildew in tomato plants. Foliar treatments are able to stop the pathogen development when they are applied as curative. Soil drench treatments induce immune response mechanisms of plants, increasing significantly callose deposition and promoting plant development.
      PubDate: 2016-08-25T03:46:02.444867-05:
      DOI: 10.1002/ps.4419
  • An integrated pest control strategy against the Asian tiger mosquito in
           northern Italy: a case study
    • Authors: Frédéric Baldacchino; Francesca Bussola, Daniele Arnoldi, Matteo Marcantonio, Fabrizio Montarsi, Gioia Capelli, Roberto Rosà, Annapaola Rizzoli
      Abstract: BACKGROUNDIn Europe, Aedes albopictus is an invasive mosquito species known to be a major nuisance as well as a vector of a range of arboviruses. A number of studies have indicated that community participation programs are an effective pest control tool to reduce mosquito populations. However, few studies have evaluated the effectiveness of a community‐based approach in Europe. In this study, we examined two Ae. albopictus control strategies that implemented a community‐based approach in northern Italy: one was a partial intervention that included a public education campaign and the larviciding of public spaces, and the other was a full intervention that additionally included a door‐to‐door campaign. This latter consisted of going door to door to actively educate residents about control measures and deliver larvicide tablets for treating catch basins at home. A site where no intervention measures were carried out was used as a control.RESULTSIn the site where a full intervention was carried out, Ae. albopictus egg density was 1.6 times less than at the site that received partial intervention, and 1.9 times less than at the non‐intervention site. No significant reduction in egg density was achieved in the partial intervention site.CONCLUSIONSIn our study, Ae. albopictus populations were most effectively reduced by larviciding both public and private catch basins. Door‐to‐door education was effective in convincing residents to apply control measures on their property; however, this method was labor intensive and costly. It may be possible to reduce personnel costs by involving volunteers or using a ‘hot spot’ approach.
      PubDate: 2016-08-19T04:55:41.556767-05:
      DOI: 10.1002/ps.4417
  • Distributions of imidacloprid, imidacloprid‐olefin and
           imidacloprid‐urea in green plant tissues and roots of rapeseed (Brassica
           napus) from artificially contaminated potting soil
    • Authors: Marcela Seifrtova; Tatana Halesova, Klara Sulcova, Katerina Riddellova, Tomas Erban
      Abstract: BackgroundImidacloprid‐urea is the primary imidacloprid soil metabolite, whereas imidacloprid‐olefin is the main plant‐relevant metabolite and is more toxic to insects than imidacloprid. We artificially contaminated potting soil and used quantitative UHPLC‐QqQ‐MS/MS to determine the imidacloprid, imidacloprid‐olefin and imidacloprid‐urea distributions in rapeseed green plant tissues and roots after 4 weeks of exposure.ResultsIn soil, the imidacloprid/imidacloprid‐urea molar ratios decreased similarly after the 250 and 2500 µg/kg imidacloprid treatments. The imidacloprid/imidacloprid‐urea molar ratios in the root and soil were similar, whereas in the green plant tissue, imidacloprid‐urea increased more than two‐fold compared to the root. Although imidacloprid‐olefin was prevalent in the green plant tissues with imidacloprid/imidacloprid‐olefin molar ratios of 2.24 and 1.47 for the 250 and 2500 µg/kg treatments, respectively, it was not detected in the root. However, imidacloprid‐olefin was detected in the soil after the 2500 µg/kg imidacloprid treatment.ConclusionsSignificant proportions of imidacloprid‐olefin and imidacloprid‐urea in green plant tissues were demonstrated. The greater imidacloprid supply increased the molar ratio of imidacloprid‐olefin/imidacloprid in the green plant tissues. The absence of imidacloprid‐olefin in the root excluded its re‐transport from leaves. The similar imidacloprid/imidacloprid‐urea ratios in the soil and root indicated that the root serves primarily for transporting these substances.
      PubDate: 2016-08-19T04:51:39.911353-05:
      DOI: 10.1002/ps.4418
  • Pathogenic nature of Syncephalastrum in Atta sexdens rubropilosa fungus
    • Authors: Mariana O. Barcoto; Felipe Pedrosa, Odair C. Bueno, Andre Rodrigues
      Abstract: BACKGROUNDLeaf‐cutter ants are considered a major herbivore and agricultural pest in the Neotropics. They are often controlled by environmentally persistent insecticides. Biological control using pathogenic fungi is regarded as an alternative for the management of these insects. Here, we assess whether the filamentous fungus Syncephalastrum sp. is a pathogenic microorganism, responsible for a characteristic disease in fungus gardens. We also characterize the damage caused by this fungus by evaluating physiological and behavioral responses of Atta sexdens rubropilosa sub‐colonies infected with Syncephalastrum sp.RESULTSSyncephalastrum sp. fulfills Koch's postulates, characterizing it as a pathogenic microorganism. Ant workers recognize the infection and remove contaminated fragments from the fungus garden. Syncephalastrum sp. infection causes an interruption of foraging activity, an increase in ant mortality, sub‐colony deterioration and increase in the amount of waste generated, all resulting in sub‐colony death. Syncephalastrum sp. also inhibits the ant fungal cultivar in vitro. The pathogenic effect of Syncephalastrum sp. does not depend on host morbidity or stress (e.g., worker mortality caused by an entomopathogenic fungus).CONCLUSIONSyncephalastrum sp. treatment resulted in progressive damage in sub‐colonies. The interactions among Syncephalastrum sp., fungus garden and ants offer new opportunities in integrated pest management of leaf‐cutting ants.
      PubDate: 2016-08-19T04:40:39.329224-05:
      DOI: 10.1002/ps.4416
  • Termiticidal lectins from Myracrodruon urundeuva (Anacardiaceae) cause
           midgut damages when ingested by Nasutitermes corniger (Isoptera;
           Termitidae) workers
    • Authors: Thâmarah A. Lima; Kenner M. Fernandes, Ana Patrícia S. Oliveira, Leonardo P. Dornelles, Gustavo F. Martins, Thiago H. Napoleão, Patrícia M.G. Paiva
      Abstract: BACKGROUNDMyracrodruon urundeuva is a hardwood tree whose bark, heartwood, and leaf contain lectins (MuBL, MuHL and MuLL, respectively) with termiticidal activity against Nasutitermes corniger. In this work, the effects of these lectins on the midgut of N. corniger workers were evaluated.RESULTSThe insects were supplied with an artificial diet containing the lectins at their respective LC50 (previously determined). Forty‐eight hours after the treatment, the midguts were dissected and fixed for histopathology analyses. Toluidine blue‐stained midguts from lectin‐treated workers showed disorganization, with presence of debris in the lumen and absence of the brush border. Fluorescence microscopy revealed that the numbers of digestive and proliferating cells were lower in lectin‐treated individuals than in the control, and caspase‐3 staining confirmed occurrence of cell apoptosis. Enteroendocrine cells were not seen in the treated individuals. The midguts from treated insects showed greater staining for peroxidase than the control, suggesting that the lectins caused oxidative stress. Staining with wheat germ agglutinin conjugated to FITC revealed that the lectins interfered with the integrity of the peritrophic matrix.CONCLUSIONThis study showed that termiticidal lectins from M. urundeuva cause severe injuries, oxidative stress and cell death in the midgut of N. corniger workers.
      PubDate: 2016-08-16T21:15:24.999825-05:
      DOI: 10.1002/ps.4415
  • Pyrethroid resistance is associated with a kdr‐type mutation (L1014F) in
           the potato tuber moth Tecia solanivora
    • Authors: Tito Bacca; Khalid Haddi, Maria Pineda, Raul Narciso C. Guedes, Eugênio E. Oliveira
      Abstract: BACKGROUNDThe Guatemalan potato tuber moth, Tecia solanivora, has been the most important pest species in Hispanico‐American potato fields since its first record on potatoes in 1956 in Guatemala. This insect pest has been spreading to other parts of the world, including the Canary Islands in Europe. The tuber moth control relies heavily on the use of insecticides, including pyrethroids. Here, we assessed the likelihood of control failures and performed concentration‐response bioassays in five Colombian strains of T. solanivora to evaluate their susceptibilities to the pyrethroid permethrin.RESULTSEvidence of control failures was observed in four strains tested, which exhibited moderate resistance levels (i.e., ranging from 5.4‐ to 24.4‐fold). However, no spatial dependence was observed between the permethrin LC50 values and the geographic distances among the tuber moth strains. In order to evaluate whether permethrin resistance was mediated by potential mutations in the para‐type sodium channels of T. solanivora, the IIS4–IIS6 region of the para gene was PCR‐amplified and sequenced from the five strains tested. As demonstrated across a range of different arthropod species that exhibited knockdown resistance (kdr), we observed a single point substitution (L1014F) at high frequencies in the para gene of all four resistant strains.CONCLUSIONSThis is the first identification of a target‐site alteration based resistance in the Guatemalan potato tuber moth T. solanivora, which is widespread and exhibits high frequencies among geographically distant strains indicating that pyrethroids are probably becoming ineffective for the control of this pest species.
      PubDate: 2016-08-08T13:18:13.091755-05:
      DOI: 10.1002/ps.4414
  • Impact of Glyphosate Resistant Corn, Glyphosate Applications, and Tillage
           on Soil Nutrient Ratios, Exoenzyme Activities and Nutrient Acquisition
    • Authors: Michael B. Jenkins; Martin A. Locke, Krishna N. Reddy, Daniel S. McChesney, R.Wade Steinriede
      Abstract: BACKGROUNDWe report results of the last two years of a 7‐year field experiment designed to test the null hypothesis: applications of glyphosate on glyphosate resistant (GR) and non‐resistant (nonGR) corn (Zea mays L.) under conventional tillage and no‐till would have no effect on soil exoenzymes and microbial activity.RESULTSBulk soil (BS) and rhizosphere soil (RS) macronutrient ratios were not affected by either GR or nonGR corn, or glyphosate applications. Differences observed between exoenzyme activities were associated with tillage rather than glyphosate applications. In 2013 nutrient acquisition ratios for bulk and rhizosphere soils indicated P limitations, but sufficient assimilable N. In 2014 P limitations were observed for bulk and rhizosphere soils, in contrast to balanced C and N acquisition ratios in rhizosphere soils. Stoichiometric relationships indicated few differences between glyphosate and non‐glyphosate treatments. Negative correlations between C:P and N:P nutrient ratios and nutrient acquisition ratios underscored the inverse relation between soil nutrient status and microbial community exoenzyme activities.CONCLUSIONSInconsistent relationships between microbial community metabolic activity and exoenzyme activity indicated an ephemeral effect of glyphosate on BS exoenzyme activity. Except for ephemeral effects, glyphosate applications appeared not to affect the function of the BS and RS exoenzymes under conventional tillage or no‐till.
      PubDate: 2016-08-05T02:45:23.642837-05:
      DOI: 10.1002/ps.4413
  • Amitraz and its metabolite differentially activate α‐ and
           β‐adrenergic‐like octopamine receptors
    • Authors: Tomo Kita; Takeshi Hayashi, Tomohiro Ohtani, Haruka Takao, Hiroshi Takasu, Genyan Liu, Hiroto Ohta, Fumiyo Ozoe, Yoshihisa Ozoe
      Abstract: BACKGROUNDAmitraz is a formamidine acaricide and insecticide used to control ticks, mites and fleas. N2‐(2,4‐Dimethylphenyl)‐N1‐methyformamidine (DPMF), a metabolite of amitraz, is thought to be an active agent that exerts acaricidal and insecticidal effects by acting as an agonist on octopamine receptors. The emergence of cattle ticks resistant to amitraz is a serious problem that requires urgent attention. The objective of this research was to determine which type of octopamine receptor is the primary target of amitraz and thereby understand the molecular mechanisms of action and resistance to amitraz.RESULTSAmitraz and DPMF potently activated Bombyx mori α‐ and β‐adrenergic‐like octopamine receptors (α‐ and β‐AL OARs) that were stably expressed in HEK‐293 cells. Notably, DPMF elevated intracellular cAMP levels with an EC50 of 79.6 pM in β‐AL OARs, the transcripts of which were prevalently and widely localized in B. mori body parts. Furthermore, DPMF elevated the intracellular Ca2+ levels, with an EC50 of 1.17 nM in α‐AL OARs.CONCLUSIONAlthough both amitraz and DPMF acted as OAR agonists, the metabolite DPMF was more potent than amitraz and differentially activated α‐ and β‐AL OARs. The present findings provide a basis for studies to examine the mechanism of amitraz resistance and to develop novel acaricides and insecticides.
      PubDate: 2016-08-03T02:50:30.805151-05:
      DOI: 10.1002/ps.4412
  • Can Herbicide Safeners Allow Selective Control of Weedy Rice Infesting
           Rice Crops?
    • Authors: Roberto Busi; Nghia K Nguyen, Bhagirath S Chauhan, Francesco Vidotto, Maurizio Tabacchi, Stephen B Powles
      Abstract: BACKGROUNDRice is a major field crop of paramount importance for global food security. However, the increased adoption of more profitable and resource‐efficient direct‐seeded rice systems (DSR) has contributed to greater weed infestations including weedy rice that has become a severe problem in several Asian regions. In this study we have developed a conceptually novel method to protect rice plants at high doses of clomazone and triallate.RESULTSThe insecticide phorate applied to rice seeds provided substantial level of protection against the herbicides clomazone or triallate. Fifteen kg phorate ha−1 significantly increased the LD50 values >2‐fold greater than rice plants treated only with clomazone. Twenty kg phorate ha−1 in combination with 2,000 g triallate ha−1 safened rice plants (80% survival) with LD50 >3.4‐fold greater than in phorate‐untreated rice. Weed control efficacy was not lowered by the presence of phorate‐treated rice seeds.CONCLUSIONWeedy rice is one of the most damaging global weeds and a major threat of DSR systems. In this study we have developed a proof‐of‐concept method to allow selective weedy rice control in rice crops. We call for herbicide discovery programs and research to identify candidate safener and herbicide combinations to achieve selective herbicide control of weedy rice and alleviate weed infestations in global rice crops.
      PubDate: 2016-08-03T02:35:24.745099-05:
      DOI: 10.1002/ps.4411
  • Rapid Killing of Bed Bugs (Cimex lectularius L.) on Surfaces using Heat:
           Application to Luggage
    • Authors: Catherine Loudon
      Abstract: BACKGROUNDThe resistance of bed bugs (Cimex lectularius L.) to chemical insecticides has motivated development of non‐chemical control methods such as heat treatment. However, because bed bugs tend to hide in cracks or crevices, their behavior incidentally generates a thermally‐insulated microenvironment for themselves. Bed bugs located on the outer surface of luggage are less insulated and potentially more vulnerable to brief heat treatment.RESULTSSoft‐sided suitcases with adult male bed bugs on the outside were exposed to an air temperature of 70‐75 °C. It took 6 minutes to kill all of the bed bugs, even those that had concealed themselves under zipper flaps or decorative piping. During heating, only one bed bug (out of 250 total) moved into the luggage (through a closed zipper). Over long periods of time (24 hours) at room temperature, adult male bed bugs on the exterior of luggage only infrequently moved inside; only 3% (5/170) had moved inside during 24 hours.CONCLUSIONSBrief exterior heat treatment of luggage is a promising way to decrease the spread of bed bugs being transported on the outer surface of luggage. This treatment will not kill bed bugs inside the luggage, but could be a component of integrated management for this pest.
      PubDate: 2016-08-01T00:01:07.142822-05:
      DOI: 10.1002/ps.4409
  • Oral delivery of dsRNA lipoplexes to German cockroach protects dsRNA from
           degradation and induces RNAi response
    • Authors: Yu‐Hsien Lin; Jia‐Hsin Huang, Yun Liu, Xavier Belles, How‐Jing Lee
      Abstract: BACKGROUNDIn the past years, the concept of RNAi application for insect pest control has been proposed, considering the disruption of vital genes. However, the efficiency of RNAi is variable between different insect groups, especially by oral delivery of dsRNA. The purpose of this study is to assess the possibilities of RNAi as a tool for pest control using oral delivery of the dsRNAs encapsulated by liposome in the German cockroach Blattella germanica, which is highly sensitive to RNAi by injection of dsRNAs.RESULTSInjecting dsRNA into the abdomen of B. germanica caused dramatic depletion of essential α‐tubulin gene and mortality. In contrast, oral delivery of the naked dsRNA resulted in lower RNAi efficiency accounted for rapid degradation of the dsRNA in the midgut of B. germanica. Notably, we have further demonstrated that continuous ingestion of dsRNA lipoplexes, which dsRNA was encapsulated with a cationic liposome carrier, was sufficient to slow down the degradation of dsRNA in the midgut and to increase the mortality of the German cockroach by significantly inhibiting α‐tubulin expression in the midgut.CONCLUSIONWe provide the empirical evidence that the formulation of dsRNA lipoplexes could be a plausible approach for insect pest control based on RNAi.
      PubDate: 2016-07-29T06:20:33.573851-05:
      DOI: 10.1002/ps.4407
  • Estimating the effect of plant‐provided food supplements on pest
    • Authors: Tarryn Schuldiner‐Harpaz; Moshe Coll
      Abstract: BACKGROUNDPlant‐provided food supplements can influence biological pest control by omnivorous predators in two counteracting ways: (i) enhance predator populations, but (ii) reduce pest consumption by individual predators. Yet the majority of studies address only one of these aspects. Here, we first tested the influence of canola (Brassica napus L.) pollen supplements on the life history of two ladybeetle species: Hoppodamia variegata (Goeze) and Coccinella septempunctata (L.). We then developed a theoretical model to simulate total pest consumption in the presence and absence of pollen supplements.RESULTSSupplementing a prey diet with canola pollen increased H. variegata larvae survival from 50% to 82%, and C. septempunctata female oviposition by 1.6 fold. Model simulations revealed a greater benefit of pollen supplements when relying on C. septempunctata for pest suppression than on H. variegata.CONCLUSIONFor these two predators, the tested pollen serves as an essential supplement to a diet of prey. However, the benefit of a mixed prey‐pollen diet was not always sufficient to overcome individual decrease in pest consumption. Taken together, our study highlights the importance of addressing both positive and negative roles of plant‐provided food supplements in considering the outcome for biological control efforts that rely on omnivorous predators.
      PubDate: 2016-07-29T06:20:23.772466-05:
      DOI: 10.1002/ps.4410
  • Determining the geographical origin of Asian longhorn beetle (Anoplophora
           glabripennis) specimens using stable isotope and trace element analyses
    • Authors: Katharina Heinrich; Larissa Collins
      Abstract: BACKGROUNDAn outbreak of EU quarantine listed pest Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambicidae), Asian Longhorn Beetle, in Kent (UK) resulted in environmentally and financially costly eradication action being taken. In this study the potential of using multi‐element stable isotope or trace element analyses to determine the geographical origin of individual specimens has been investigated.RESULTSThe isotope ratios of A. glabripennis individuals for hydrogen varied within and across 5 locations. Carbonisotope ratios fell within the expected values for C3 plants (trees using the photosynthetic pathway common for moderate climates). Nitrogen isotope ratios indicated separation of UK laboratory from American (New York, Ohio, Massachusetts) beetles; whilst sulfur isotope ratios distinguished beetles from New York against the other 4 locations. Three trace elements (TEs) separated UK laboratory‐reared beetles from American beetles (Ohio and New York) with ~ 68% confidence.CONCLUSIONSStable isotope and TE analyses show potential to differentiate between newly arrived A. glabripennis individuals and those from previously undetected in‐country populations, which would be of immediate practical benefit in making appropriate strategic decisions on surveillance and eradication. Analyses of additional samples (i) from the same populations, (ii) different locations and (iii) variety of host trees will enhance the overall picture.
      PubDate: 2016-07-29T06:15:45.448612-05:
      DOI: 10.1002/ps.4408
  • Intermediate derivatization method in the discovery of new acaricide
           candidate: synthesis of N‐substituted piperazines derivatives and their
           activity against phytophagous mites
    • Authors: Yong Xie; Ying Xu, Changling Liu, Aiying Guan, Lanfeng Ban, Fei Ding, Wei Peng
      Abstract: BACKGROUNDTo discover and exploit novel acaricidal compounds, a series of novel N‐substituted piperazines derivatives were designed and synthesized using a tert‐butyl piperazine‐1‐carboxylate as starting material by intermediate derivatization methods and their acaricidal activities were evaluated.RESULTSThe acaricidal activity showed compounds 11 and 12 exhibited significant acaricidal activity against adults of Tetranychus cinnabarinus in greenhouse tests. Compound 12 in particular was found to be the best potential candidate acaricide and proved more active than that of the commercial positive controls spirodiclofen and pyridaben, with an LC50 of 0.8977 mg L−1. The results of acaricidal activities against larvae and eggs of Tetranychus cinnabarinus indicated that compound 12 possessed equivalent larvicidal activity to spirodiclofen and higher larvicidal activity than pyridaben. Meanwhile, compound 12 showed less ovicidal activity than pyridaben, but higher activity than spirodiclofen. Furthermore, the results of the field trial demonstrated that compound 12 could effectively control Panonychus citri and Panonychus ulmi with long‐lasting persistence and rapid‐acting property.CONCLUSIONSThe present work indicates that compound 12 could be a novel acaricide candidate for spider mites control.
      PubDate: 2016-07-23T03:15:32.568748-05:
      DOI: 10.1002/ps.4369
  • Synthesis and Insecticidal Activity of Novel Pyrimidine Derivatives
           Containing Urea pharmacophore against Aedes aegypti
    • Authors: Xing‐Hai Liu; Qiao Wang, Zhao‐Hui Sun, David E. Wedge, James J. Becnel, Alden S. Estep, Cheng‐Xia Tan, Jian‐Quan Weng
      Abstract: BACKGROUNDAedes aegypti is a major mosquito vector for the transmission of serious diseases, especially dengue and yellow fever. More than one billion people in developing countries are at risk. The widespread and continual use of pesticides can lead to resistant mosquitoes. In order to maintain mosquito control gains, it is critical to develop and evaluate novel bioactive molecules that differ in mode of action from currently used products.RESULTSA series of novel pyrimidine derivatives were designed and synthesized. Their structures were elucidated by 1H NMR and HRMS. Biological activities of these compounds were tested against Aedes aegypti. Many of them exhibited insecticidal activity against adult and larval mosquitoes. Compound 4d displayed relatively good activity to reach 70% mortality at 2 µg/mL. Furthermore, DFT (Density functional theory) calculations were established to study the structure‐activity relationship of these novel compounds.CONCLUSIONA practical synthetic route for pyrimidine derivatives is presented. This study suggests that these pyrimidine derivatives exhibited some activity against the yellow fever mosquito, and with further structure modification, could be novel lead compounds for the development of insecticides against mosquitoes.
      PubDate: 2016-07-23T03:15:26.888181-05:
      DOI: 10.1002/ps.4370
  • Efficacy of tebuconazole embedded in biodegradable
           poly‐3‐hydroxybutyrate to inhibit the development of Fusarium
           moniliforme in soil microecosystems
    • Authors: Tatiana G Volova; Svetlana V Prudnikova, Natalia O Zhila, Olga N Vinogradova, Anna A Shumilova1, Elena D Nikolaeva, Evgeniy G Kiselev, Ekaterina I Shishatskaya
      Abstract: BackgroundAn important line of research is the development of a new generation of formulations with targeted and controlled release of the pesticide, using matrices made from biodegradable materials. In this study, slow‐release formulations of the fungicide tebuconazole (TEB) have been prepared by embedding it into the matrix of poly‐3‐hydroxybutyrate (P3HB) in the form of films, microgranules, and pellets.ResultsThe average rates of P3HB degradation rates were determined by the geometry of the formulation, reaching for 63 days 0.095‐0.116; 0.081‐0.083; 0.030‐0.055 mg d−1 for films, microgranules, and pellets, respectively. The fungicidal activity of P3HB/TEB against the plant pathogen Fusarium moniliforme was compared with that of the commercial formulation Raxil Ultra. A pronounced fungicidal effect of the experimental P3HB/TEB formulations was observed in 2–4 weeks after application, and it was retained for 8 weeks, without affecting significantly the development of soil aboriginal microflora.ConclusionsTEB release can be regulated by the process employed to fabricate the formulation and the fungicide loading and that TEB accumulates in the soil gradually, as the polymer is degraded. The experimental forms of TEB embedded in the slowly degraded P3HB can be used as a basis for developing slow‐release fungicide formulations.
      PubDate: 2016-07-22T09:20:27.285264-05:
      DOI: 10.1002/ps.4367
  • Forward selection for multiple resistance across the non‐selective
    • Authors: Pablo Fernández; Ricardo Alcántara, María D. Osuna, Martin Vila‐Aiub, Rafael De Prado
      Abstract: BACKGROUNDIn the Mediterranean area, Lolium species have evolved resistance to glyphosate after decades of continue use without other alternative chemicals in perennial crops (olive, citrus and vineyard). In recent years, oxyfluorfen alone or mixed with glyphosate and glufosinate have been introduced as chemical options to control dicot and grass weeds.RESULTSDose response studies confirmed that three glyphosate resistant Lolium weed species (L. rigidum, L. perenne, L. multiflorum) collected from perennial crops in the Iberian Peninsula have also evolved resistance to glufosinate and oxyfluorfen herbicides, despite their recent introduction. Based on LD50 resistance parameter, resistance factor was similar among Lolium species and ranged from 14‐21‐fold and 10‐12‐fold for oxyfluorfen and glufosinate, respectively. Similarly, about 14‐fold resistance to both oxyfluorfen and glufosinate was estimated in average for the three Lolium species when growth reduction (GR50) was assessed. This study identified oxyfluorfen resistance in a grass species for the first time.CONCLUSIONA major threat to sustainability of perennial crops in the Iberian Peninsula is evident as multiple resistance to non‐selective glyphosate, glufosinate and oxyfluorfen herbicides has evolved in L. rigidum, L. perenne and L. multiflorum weeds.
      PubDate: 2016-07-22T09:20:24.457363-05:
      DOI: 10.1002/ps.4368
  • Susceptibility of Selected Boreal Fruits and Berries to the Invasive Pest
           Drosophila suzukii (Diptera: Drosophilidae)
    • Authors: Catherine M Little; Thomas W Chapman, Debra L Moreau, N Kirk Hillier
      Abstract: BACKGROUNDDrosophila suzukii Matsumara has recently emerged as a major invasive pest species in soft‐skinned fruits in berries throughout N. America and Europe. Its distribution has spread so rapidly that little is known of the extent of fruit susceptibility, particularly in boreal regions. Populations of D. suzukii increase dramatically in late summer in boreal regions, concurrent with fruiting seasons for commercially and culturally significant fruits and berries. We tested fruit preference and susceptibility of lingonberry, blueberry, chokecherry, sea buckthorn, and raspberry fruits to D. suzukii.RESULTSFemale D. suzukii attempted to oviposit on all fruit types tested. Fruits with lower brix and lower pH levels were preferred in choice tests. Undamaged lingonberries were relatively safe from infestation; however, bruised or frost‐damaged fruits were easily penetrated. Sea buckthorn and raspberry fruits were highly preferred.CONCLUSIONSAlthough blueberry growers have experienced severe economic crop losses due to D. suzukii, we have found that blueberries were the least preferred of fruits tested. This suggests that D. suzukii are largely opportunistic and highlights the importance of fruit phenology in fruit susceptibility.
      PubDate: 2016-07-22T09:15:59.719798-05:
      DOI: 10.1002/ps.4366
  • Systemic RNAi in the small hive beetle (Aethina tumida Murray, Coleoptera:
           Nitidulidae), a serious pest of the European honey bee (Apis mellifera)
    • Authors: Michelle E. Powell; Hannah M. Bradish, John A. Gatehouse, Elaine C. Fitches
      Abstract: BACKGROUNDAethina tumida is a serious pest of the European honey bee (Apis mellifera) in North America and Australia. Here we investigate whether Laccase 2, phenoloxidase gene essential for cuticle sclerotization and pigmentation in many insects, and vacuolar‐ATPase V‐type subunit A, vital for the generation of proton gradients used to drive a range of transport processes, could be potential targets for RNAi‐mediated control of A. tumida.RESULTSInjection of V‐ATPase subunit A (5 ng) and Laccase 2 (12.5 ng) dsRNAs resulted in 100 % larval mortality, qPCR confirmed significant decreases and enhanced suppression of transcript levels over time. Oral delivery of V‐ATPase subunit A dsRNA in solutions resulted in 50 % mortality, however gene suppression could not be verified. We suggest that the inconsistent RNAi effect was a consequence of dsRNA degradation within the gut due to the presence of extracellular nucleases. Target specificity was confirmed by a lack of effect on survival or gene expression in honey bees injected with A. tumida dsRNAs.CONCLUSIONSThis is the first study to show evidence for systemic RNAi in A. tumida in response to injected dsRNA but further research is required to develop methods to induce RNAi effects via ingestion.
      PubDate: 2016-07-22T09:10:32.046249-05:
      DOI: 10.1002/ps.4365
  • Recurrent selection with reduced 2,4‐D amine doses results in the rapid
           evolution of 2,4‐D herbicide resistance in wild radish (Raphanus
           raphanistrum L.)
    • Authors: Michael B. Ashworth; Michael J. Walsh, Ken C. Flower, Stephen B. Powles
      Abstract: BACKGROUNDWhen used at effective doses, weed resistance to auxinic herbicides has been slow to evolve when compared to other modes of action. Here we report the evolutionary response of a herbicide‐susceptible population of wild radish (Raphanus raphanistrum L.) and confirm that sub‐lethal doses of 2,4‐D amine can lead to the rapid evolution of 2,4‐D resistance and cross resistance to acetolactate synthase (ALS) inhibiting herbicides.RESULTSFollowing four generations of 2,4‐D selection, the progeny of a herbicide‐susceptible wild radish population evolved 2,4‐D resistance, increasing the LD50 from 16 g ha−1 to 138 g ha−1. Along with 2,4‐D resistance, cross resistance to the ALS‐inhibiting herbicides metosulam (4.0‐fold), and chlorsulfuron (4.5‐fold) was evident. Pre‐treatment of the 2,4‐D‐selected population with the cytochrome P450 inhibitor, malathion, restored chlorsulfuron to full efficacy, indicating that cross resistance to chlorsulfuron was likely due to P450 catalysed enhanced rates of herbicide metabolism.CONCLUSIONThis study is the first to confirm the rapid evolution of auxinic herbicide resistance through the use of low doses of 2,4‐D and serves as a reminder that 2,4‐D must always be used at highly effective doses. With the introduction of transgenic auxinic herbicide resistant crops in the America's there will be a marked increase in auxinic herbicide use and therefore the risk of resistance evolution. Auxinic herbicides should be used only at effective doses and with diversity if resistance is to remain a minimal issue.
      PubDate: 2016-07-21T11:50:26.311405-05:
      DOI: 10.1002/ps.4364
  • Costs and benefits of insecticide and foliar nutrient applications to
           HLB‐infected citrus trees
    • Authors: James A. Tansey; Pilar Vanaclocha, Cesar Monzo, Moneen Jones, Philip A. Stansly
      Abstract: BACKGROUNDThe Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae), vectors ‘Candidatus Liberibacter asiaticus’ that causes huanglongbing (HLB). In Florida, HLB incidence is approaching 100% statewide. Yields have decreased and production costs have increased since 2005. Despite this, some growers are maintaining a level of production and attribute this in part to aggressive psyllid control and foliar nutrition sprays. However, the value of these practices is debated. A replicated field study was initiated in 2008 in a commercial block of ‘Valencia’ sweet orange trees to evaluate individual and combined effects of foliar nutrition and ACP control. Results from 2012–2016 are presented.RESULTSInsecticides consistently reduced ACP populations. However, neither insecticide nor nutrition applications significantly influenced HLB incidence nor PCR copy number in mature trees. In reset trees, infection continued to build and reached 100% in all treatments. Greatest yields (kg fruit/ ha) and production (kg s/ ha) were obtained from trees receiving both insecticides and foliar nutrition.CONCLUSIONSAll treatments resulted in production and financial gains relative to controls. However, material and application costs associated with the nutrition component offset these gains resulting in lesser benefits than insecticides applied alone.
      PubDate: 2016-07-18T05:53:45.896665-05:
      DOI: 10.1002/ps.4362
  • Structure‐based bioisosterism design, synthesis, insecticidal activity
           and structure‐activity relationship (SAR) of anthranilic diamides
           analogs containing 1,2,4‐oxadiazole rings
    • Authors: Qi Liu; Rui Zhu, Shang Gao, Shi‐Han Ma, Hai‐Jun Tang, Jian‐Jun Yang, Ya‐Mei Diao, Hong‐Lei Wang, Hong‐Jun Zhu
      Abstract: BACKGROUNDAnthranilic diamides derivatives are among the most important classes of synthetic insecticides. Besides the 1,2,4‐oxadiazole heterocycle, a bioisostere of amide, has been extensively used in pesticide. In order to discover novel molecules with high insecticidal activities, a series of anthranilic diamides analogs containing 1,2,4‐oxadiazole rings were designed and synthesized.RESULTSA series of novel anthranilic diamides derivatives containing 1,2,4‐oxadiazole were obtained, and confirmed by 1H NMR, 13C NMR and HRMS. The structure of 3‐bromo‐N‐(4‐chloro‐2‐methyl‐6‐(3‐((methylsulfonyl)methyl)‐1,2,4‐oxadiazol‐5‐yl)phenyl)‐1‐(3‐chloropyridin‐2‐yl)‐1H‐pyrazole‐5‐carboxamide was further characterized by X‐ray diffraction analysis. In addition, bioassays showed that most of the newly synthesized compounds displayed 100 % mortality against Plutella xylostella at 100 mg L−1. And compound 3IIl showed 90 % larvicidal activities at the concentration of 0.5 mg L−1. The LC50 value of 3IIl was 0.20 mg L−1, which indicated that it may be used as potential leading compound for further structural optimization. Furthermore, a brief comparative molecular field analysis models were established to study the structure‐activity relationship of the title compounds.CONCLUSIONCompound 3IIl may be used as potential leading compound for further structural optimization. And the SAR and CoMFA model could provide reliable clues for further structural optimization.
      PubDate: 2016-07-18T05:53:44.735627-05:
      DOI: 10.1002/ps.4363
  • Homozygous and heterozygous point mutations in succinate dehydrogenase
           subunits b, c, and d of Rhizoctonia cerealis conferring resistance to
    • Authors: Hai‐Yan Sun; Chao‐Qun Lu, Wei Li, Yuan‐Yu Deng, Huai‐Gu Chen
      Abstract: BACKGROUNDThifluzamide, a succinate dehydrogenase inhibitor (SDHI) fungicide, is a promising fungicide for controlling wheat sharp eyespot (WSE). WSE is caused by Rhizoctonia cerealis. Information on the resistance mechanism of this pathogen to thifluzamide remains unavailable.RESULTSWe used selective re‐culturing and UV mutagenesis to generate thifluzamide resistant mutants. Thifluzamide‐resistant mutants were only generated through UV mutagenesis. Sequence analysis of succinate dehydrogenase (Sdh) genes revealed that two mutants had no mutation in RCSdhB, RCSdhC, and RCSdhD and the other 18 mutants all had at least a one mutation in RCSdhB, RCSdhC, or RCSdhD, either in a homozygous or heterozygous state. The majority of mutants included either RCSdhD‐H116Y or RCSdhC‐H139Y. They showed slight resistance to boscalid, bixafen, and penflufen. Only one mutant possessed RCSdhB‐H246Y and it showed medium resistance to boscalid, penflufen, and a slight resistance to bixafen. All the thifluzamide mutants were sensitive to flutolanil. Compared with their parental isolates, these mutants present no or minor fitness penalties.CONCLUSIONHomozygous and heterozygous point mutations in the succinate dehydrogenase subunits b, c, and d of R. cerealis may be involved in thifluzamide resistance.
      PubDate: 2016-07-14T09:06:00.392682-05:
      DOI: 10.1002/ps.4361
  • Synthesis and Biological Activity of a New Class of Insecticides: the
    • Authors: Joseph D. Eckelbarger; Marshall H. Parker, Maurice C. H. Yap, Ann M. Buysse, Jonathan M. Babcock, Ricky Hunter, Yelena Adelfinskaya, Jack G. Samaritoni, Negar Garizi, Tony K. Trullinger
      Abstract: BACKGROUNDOptimization studies on a high throughput screening (HTS) hit led to the discovery of a series of N‐(6‐arylpyridazin‐3‐yl)amides with insecticidal activity. It was hypothesized that the isosteric replacement of the pyridazine ring with a 1,3,4‐thiadiazole ring could lead to more potent biological activity and/or broader sap‐feeding pest spectrum. The resulting N‐(5‐aryl‐1,3,4‐thiadiazol‐2‐yl)amides were explored as a new class of insecticides.RESULTSSeveral methods for 2‐amino‐1,3,4‐thiadiazole synthesis were used for the preparation of key synthetic intermediates. Subsequent coupling to variously substituted carboxylic acid building blocks furnished the final targets, which were tested for insecticidal activity against susceptible strains of Aphis gossypii (Glover) (cotton aphid), Myzus persicae (Sulzer) (green peach aphid), and Bemisia tabaci (Gennadius) (sweetpotato whitefly).CONCLUSIONSStructure‐activity relationship (SAR) studies on both the amide tail and the aryl A‐ring of novel N‐(5‐aryl‐1,3,4‐thiadiazol‐2‐yl)amides led to a new class of insecticidal molecules active against sap‐feeding insect pests.
      PubDate: 2016-07-14T08:55:38.584957-05:
      DOI: 10.1002/ps.4359
  • Pro‐Insecticidal Approach Towards Increasing In Planta Activity
    • Authors: Lawrence C. Creemer; Natalie C. Giampietro, William Lambert, Maurice C. Yap, Gerrit J. deBoer, Yelena Adelfinskaya, Scott Castetter, Frank J. Wessels
      Abstract: BACKGROUNDThe adrenergic mode of action was investigated for the development of potential new insecticides. Clonidine related analogs were tested against Myzus persicae (Sulzer) and Bemisia tabaci (Gennadius). Clonidine analogs lack translation due to a possible vacuole trapping mechanism. Physical properties modulation via a pro‐drug approach was attempted to overcome this mechanism.RESULTSClonidine showed insecticidal activity against M. persicae and B. tabaci. A pro‐drug of a known open‐chain analog of clonidine, was developed. While the pro‐drug had decreased pKa and increased lipophillicity and displayed good activity against M. persicae and B. tabaci, the activity did not translate on cotton. Metabolic studies showed the pro‐drug was quickly metabolized to the parent compound, and was further metabolized to a known vacuole‐trapped oxazoline analog.CONCLUSIONSAdrenergic active compounds, such as clonidine analogs, show potential as insecticides; however, a designed pro‐drug approach did not overcome lack of translation in this case. Studies confirmed that the synthesized pro‐drug analog metabolized in planta to a proposed vacuole‐trapped compound. One possible explanation for the failure of this approach is that the rate of metabolism and vacuole trapping is faster than translaminar flow and therefore the released pesticide is not biologically available to the target organism.
      PubDate: 2016-07-14T08:55:27.754405-05:
      DOI: 10.1002/ps.4358
  • Effects of trans‐2‐Hexenal on Reproduction, Growth and Behavior and
           Efficacy against Pinewood Nematode, Bursaphelenchus xylophilus
    • Authors: Le Cheng; Shuangyu Xu, Chunmei Xu, Hongbao Lu, Zhengqun Zhang, Daxia Zhang, Wei Mu, Feng Liu
      Abstract: BACKGROUNDBursaphelenchus xylophilus is a serious quarantined pest that causes severe damage and major economic losses to pine forests. Because of the adverse effects of some traditional nematicides on human and the environment, new plant toxicants against these nematodes have intensified. Nematicidal activity of trans‐2‐hexenal, which is a six carbon aldehyde present in many plants, was tested against the nematode.RESULTStrans‐2‐Hexenal showed significant efficacy against B. xylophilus at a dose range of 349.5‐699 g m‐3 by fumigation of pine wood logs. Additionally, it had significant nematicidal activity against different life stages of B. xylophilus in‐vitro test, with second‐stage larvae (L2s) being the most sensitive, which had LC50 value of 9.87 µg mL‐1 at 48 h. Egg hatch was also significantly inhibited. Further studies revealed that trans‐2‐hexenal inhibited the reproductive activity of B. xylophilus, with negative effects on reproduction rate and egg numbers. Moreover, trans‐2‐hexenal reduced the body length of B. xylophilus. Respiratory rate and thrashing behavior of B. xylophilus also decreased following treatment with this compound.CONCLUSIONtrans‐2‐hexenal had significant nematicidal activity against B. xylophilus, providing a basis for elucidation of the mode of action of trans‐2‐hexenal against plant parasitic nematodes in future studies.
      PubDate: 2016-07-14T08:55:25.229031-05:
      DOI: 10.1002/ps.4360
  • Effect of plant resistance and BioAct WG (Purpureocillium lilacinum strain
           251) on Meloidogyne incognita in a tomato–cucumber rotation in a
    • Authors: Ariadna Giné; Francisco J Sorribas
      Abstract: BACKGROUNDThe effectiveness of combining resistant tomato with BioAct WG (Purpureocillium lilacinum strain 251; Pl251) against Meloidogyne incognita was assessed in a tomato‐cucumber rotation in greenhouse over two years. Additionally, the enzymatic activity of the fungus, the percentage of fungal egg and juvenile parasitism, cardinal temperatures and the effect of water potential on mycelial growth and the soil receptivity to Pl251 were determined in vitro.RESULTSPlant resistance was the only factor that suppressed nematode and crop yield losses. Percentage of egg parasitism in plots treated with BioAct WG was less than 2.6 %. However under in vitro conditions, Pl251 showed protease, lipase, and chitinase activities, and parasitized 94.5 % of eggs, but no juveniles. Cardinal temperatures were 14.2, 24‐26, and 35.4 °C. The maximum Pl251 mycelial growth was at ‐0.25 MPa and 25 °C. Soil temperatures and water potential in the greenhouse were in the range of the fungus. However, soil receptivity was less in greenhouse soil, irrespective of sterilization, than in sterilized sand.CONCLUSIONSPlant resistance was the only factor able to suppress nematode densities, disease severity and yield losses, and to protect the following cucumber crop. Environmental factors involved in soil receptivity could have negatively affected fungus effectiveness.
      PubDate: 2016-07-14T08:55:23.174418-05:
      DOI: 10.1002/ps.4357
  • Effects of Residual Novaluron on Reproduction in Alfalfa Leafcutting Bees,
           Megachile rotundata F. (Megachilidae)
    • Authors: Theresa L. Pitts‐Singer; James D. Barbour
      Abstract: BackgroundThe chitin synthesis inhibitor novaluron can suppress pests that affect alfalfa seed production, but can negatively impact reproductive success in the alfalfa pollinator Megachile rotundata. Novaluron is considered a reduced risk insecticide because it disrupts ecdysis and is nonlethal to adults, but some exposed adult insects have fewer eggs and suppressed egg hatch. For this experiment, bees nested in field cages where they were exposed to alfalfa never treated with novaluron, alfalfa that was recently sprayed, or alfalfa that had been sprayed one and two weeks earlier.ResultsCompared to control, greater proportions of dead eggs and larvae and lower proportions of live prepupae occurred when bees were exposed to recent novaluron sprays as well as one‐ or two‐week old spray residues. Two possible routes of residual pesticide exposure were revealed. Mother bees become contaminated through ingestion or direct contact. Or, pollen‐nectar provisions become contaminated with novaluron 1) on or within leaf pieces that surround provisions or 2) transferred from mother bees’ bodies to provisions.ConclusionWe found strong immature mortality effects of novaluron and its residues on M. rotundata. Understanding all possible pesticide exposure routes for pollinating bees enhances decision‐making for maintaining bee populations while protecting crops.
      PubDate: 2016-07-12T09:25:19.625365-05:
      DOI: 10.1002/ps.4356
  • Sorption and desorption characteristics of methyl bromide during and after
           fumigation of pine (Pinus radiata D. Don) logs
    • Authors: Matthew Hall; Adriana Najar‐Rodriguez, Anthony Adlam, Alistair Hall, Don Brash
      Abstract: BACKGROUNDThe sorption and desorption characteristics of methyl bromide (MB) were determined during and after fumigation of recently harvested pine (Pinus radiata D. Don) logs. The effects of dose (48 or 120 g m−3), degree of bark cover (0, 50 or 100%) and end‐grain sealing (sealed or unsealed) on sorption and desorption were determined over time.RESULTSSorption of MB was proportional to the dose applied and dependent on the amount of end‐grain sealed. After 16 h, an average of 70.7 ± 2.5% of the initial concentration remained in the treated space when end‐grains were sealed whereas only 47.3 ± 2.5% remained when unsealed. During aeration, MB was released from logs initially ranging from 2.8 to 8.8 g.h m−3, depending on the treatment. The rate of desorption quickly decreased during aeration.CONCLUSIONThe surface area of a log is the most important factor influencing MB sorption and desorption rates, with greater surface area resulting in a greater (de)sorption rates. Sorption data can now be combined with insect toxicity data to estimate a minimum effective dose of MB for further evaluation; while desorption data can be combined with fumigant plume modelling to assess worker safety.
      PubDate: 2016-07-12T09:16:04.038919-05:
      DOI: 10.1002/ps.4355
  • Insecticidal Activity of Novel Thioureas and Isothioureas
    • Authors: William T. Lambert; Miriam E. Goldsmith, Thomas C. Sparks
      Abstract: BACKGROUNDWe hypothesized that exploration of chemical space around compounds with reported insecticidal activity could be a viable strategy for discovering novel, insecticidally active areas of chemistry.RESULTSA series of thioureas and isothioureas were prepared as part of a scaffold‐hopping effort around known insecticidal compounds. Many of these compounds showed excellent activity against key sap‐feeding insect pests in insecticidal bioassays. While analogs bearing monocyclic thiophene head groups showed activity against Myzus persicae (green peach aphid), analogs with diarylethane head groups were active against both M. persicae and Bemisia tabaci (sweetpotato whitefly). Despite compelling activity in these laboratory tests, these compounds showed diminished activity when applied to host plants via tracksprayer.CONCLUSIONSThe initial hypothesis that structural modification of molecules reported to have insecticidal activity would yield novel compounds which also exhibit insecticidal activity was validated. Despite excellent activity in laboratory bioassays, these new compounds failed to show compelling activity in more demanding tracksprayer tests.
      PubDate: 2016-07-08T08:35:25.173009-05:
      DOI: 10.1002/ps.4353
  • Weed seed inactivation in soil mesocosms via biosolarization with mature
           compost and tomato processing waste amendments
    • Authors: Yigal Achmon; Jesús D. Fernández‐Bayo, Katie Hernandez, Dlinka G. McCurry, Duff R. Harrold, Joey Su, Ruth M. Dahlquist‐Willard, James J. Stapleton, Jean S. VanderGheynst, Christopher W. Simmons
      Abstract: BACKGROUNDBiosolarization is a fumigation alternative that combines passive solar heating with amendment‐driven soil microbial activity to temporarily create antagonistic soil conditions, such as elevated temperature and acidity, that can inactivate weed seeds and other pest propagules. The aim of this study was to use a mesocosm‐based field trial to assess soil heating, pH, volatile fatty acid accumulation, and weed seed inactivation during biosolarization.RESULTSBiosolarization for 8 days using 2% mature green waste compost and 2 or 5% tomato processing residues in the soil resulted in accumulation of volatile fatty acids in the soil, particularly acetic acid, and >95% inactivation of Brassica nigra and Solanum nigrum seeds. Inactivation kinetics data showed that near complete weed seed inactivation in soil was achieved within the first 5 days of biosolarization. This was significantly greater than the inactivation achieved in control soils that were solar heated without amendment or were amended but not solar heated.CONCLUSIONThe composition and concentration of organic matter amendments in soil significantly affected volatile fatty acid accumulation at various soil depths during biosolarization. Combining solar heating with organic matter amendment resulted in accelerated weed seed inactivation compared to either approach alone.
      PubDate: 2016-07-08T08:35:21.04782-05:0
      DOI: 10.1002/ps.4354
  • Eradicating grey squirrel Sciurus carolinensis from urban areas: an
           innovative decision making approach based on lessons learnt in Italy
    • Authors: Daniele Paoloni; Valentina La Morgia
      Abstract: BACKGROUNDEradication of Invasive Alien Species supports the recovery of native biodiversity. In Europe, a new Regulation introduces obligations to eradicate the most harmful invasive species. However, eradications of charismatic mammals may encounter strong oppositions. Considering the case study of the Eastern grey squirrel (Sciurus carolinensis Gmelin, 1788) in central Italy, we developed a structured decision making technique, based on a Bayesian Decision Network model and explicitly considering the plurality of environmental values of invasive species management to reduce potential social conflicts.RESULTSThe model identified priority areas for management activities. These areas corresponded to the core of the grey squirrel range, but they also included peripheral zones, where rapid eradication is fundamental to prevent the spread of squirrels. However, when the model was expanded also integrating the attitude of citizens towards the project, the intervention strategy slightly changed. In some areas, the citizens’ support was limited and this resulted in a reduced overall utility of intervention.CONCLUSIONThe suggested approach extends the scientific basis for the management decisions, evaluated in terms of technical efficiency, feasibility and social impact. Here, the Bayesian Decision Network model analysed the potential technical and social consequences of management actions and it responded to the need of transparency in the decision process, but it can be easily extended to consider further issues, common in many mammal eradication programs. Thanks to its flexibility and comprehensiveness, it provides an innovative example of how to plan rapid eradication or control activities, as required by the new EU Regulation.
      PubDate: 2016-07-01T07:40:24.218874-05:
      DOI: 10.1002/ps.4352
  • Toxicity of squamocin on Aedes aegypti larvae, its predators and human
    • Authors: Marilza S. Costa; Antônio E. G. Santana, Leandro L. Oliveira, José E. Serrão
      Abstract: BACKGROUNDThe mosquito Aedes aegypti transmit virus that cause diverse human diseases and the vector control is an important strategy to avoid their propagation. Plants in Annonaceae are recognized as source to molecules with use in medical and agriculture fields. Molecules of secondary metabolites of Annonaceae plants exhibit insecticidal potential against insect pest and vectors, with highlight to acetogenins that show high toxicity with low doses, which encouraged research to producing new insecticide molecules. Herein, we identify an acetogenin from Annona mucosa seeds (chemical analysis) and provide toxicity test against larvae of A. aegypti (target insect), its predators Culex bigoti and Toxorhynchites theobaldi (non‐target insects) and cytotoxicity to human leukocytes.RESULTSWe identify squamocin (C37H66O7) a fatty acid with presence of bis‐tetrahydrofuran ring. In A. aegypti, this compound exhibited behavioral disturb before larval death, high mortality and require low concentrations to LC50 = 0.01 µg/mL and LC90 = 0.11 µg/mL. However, in predators and human leukocytes the squamocin showed non‐effect toxic which indicate selectivity this molecule to non‐target organism.CONCLUSIONWe identify squamocin from A. mucosa seeds and reported lethal action against A. aegypti and show that it is selective for non‐target insects and has low cytotoxicity on human cell.
      PubDate: 2016-07-01T07:35:40.975195-05:
      DOI: 10.1002/ps.4350
  • Studies toward Understanding the SAR around the Sulfoximine Moiety of the
           Sap‐Feeding Insecticide Sulfoxaflor
    • Authors: Ann M. Buysse; Benjamin M. Nugent, Nick X. Wang, Zoltan Benko, Nneka Breaux, Richard Rogers, Yuanming Zhu
      Abstract: BACKGROUNDThe discovery of sulfoxaflor (Isoclast™ active) stemmed from a novel scaffold‐based approach toward identifying bioactive molecules. It exhibits broad spectrum control of many sap‐feeding insect pests, including aphids, whiteflies, hoppers and Lygus. Systematic modifications of the substituents flanking each side of the sulfoximine moiety were carried out to determine if these changes would improve potency.RESULTSStructure activity relationship (SAR) studies showed that with respect to the methylene linker, both mono‐ and di‐substitution with alkyl groups of varying sizes as well as cyclic analogs exhibited excellent control of cotton aphids. However against green peach aphids a decrease in activity was observed with substituents larger than ethyl as well as larger cycloalkyl groups. At the terminal tail there appeared to be a narrow steric tolerance as well, with linear groups or small rings more active against green peach aphids than bulkier groups.CONCLUSIONSA novel series of compounds which explored the substituents flanking the sulfoximine moiety of sulfoxaflor were prepared and tested for bioactivity against cotton aphids and green peach aphids. SAR studies indicated that a decrease in green peach aphid potency was observed at the methylene linker as well as the terminal tail with bulkier substituents. A quantitative structure activity relationship (QSAR) analysis of the compounds revealed significant correlation of activity with two molecular descriptors, vol (volume of a molecule) and GCUT_SMR_3 (molar refractivity). This predictive model helps explain the observed activity with the various substituents.
      PubDate: 2016-07-01T07:35:37.990813-05:
      DOI: 10.1002/ps.4351
  • Unrelenting spread of the alien monk parakeet Myiopsitta monachus in
           Israel. Is it time to sound the alarm?
    • Authors: Jose Luis Postigo; Assaf Shwartz, Diederik Strubbe, Antonio‐Román Muñoz
      Abstract: BACKGROUNDMonk parakeets, Myiopsitta monachus Boddaert are native to South America, but have established populations in North America, Europe, Africa and Asia. They are claimed to act as agricultural pests in their native range, and their communal stick nests may damage human infrastructure. Although several monk parakeet populations are present in the Mediterranean basin and temperate Europe, little empirical data are available on their population size and growth, distribution, and potential impact. We investigated the temporal and spatial dynamics of monk parakeets in Israel to assess their invasion success and potential impact on agriculture.RESULTSMonk parakeet populations are growing exponentially at a higher rate than that reported elsewhere. The current Israeli population of monk parakeets comprises approximately 1500 individuals. The distribution of the species has increased and shifted from predominantly urban areas to agricultural landscapes.CONCLUSIONSIn Israel monk parakeet populations are growing fast and have dispersed rapidly from cities to agricultural areas. At present, reports of agricultural damage are scarce. A complete assessment of possible management strategies is urgently needed before the population becomes too large and widespread to allow for cost‐effective mitigation campaigns to be implemented.
      PubDate: 2016-07-01T07:35:32.584788-05:
      DOI: 10.1002/ps.4349
  • Toxicities and effects of insecticidal toxic baits to control Drosophila
           suzukii and Zaprionus indianus (Diptera: Drosophilidae)
    • Authors: Felipe Andreazza; Daniel Bernardi, Cleber A Baronio, Joel Pasinato, Dori E Nava, Marcos Botton
      Abstract: BACKGROUNDDrosophila suzukii is a primary insect pest that causes direct damage to fruits with a thin epidermis such as strawberries, cherries, and blueberries. In strawberry fields, the co‐occurrence of D. suzukii and Zaprionus indianus has increased production losses. This study evaluated the toxicities and effects of insecticidal baits to control adults and larvae of both D. suzukii and Z. indianus.RESULTSOrganophosphates (dimethoate and malathion), spinosyns (spinosad and spinetoram), pyrethroid (lambda‐cyhalothrin) and diamide (cyantraniliprole) insecticides, exhibited high toxicity to both adults and larvae of D. suzukii and Z. indianus (mortality > 80%) in topical and dip bioassays. However, when the insecticides were mixed with a feeding attractant, a positive effect was observed only for adults of D. suzukii. Insecticides containing neonicotinoids (acetamiprid and thiamethoxam) and pyrolle (chlorfenapyr) caused intermediate mortality to adults of D. suzukii (40% to 60%) and low mortality for Z. indianus (mortality 
      PubDate: 2016-06-29T02:45:21.460099-05:
      DOI: 10.1002/ps.4348
  • Enhancing the Effectiveness of Biological Control Programs of Invasive
           Species through a More Comprehensive Pest Management Approach
    • Authors: Joseph M DiTomaso; Robert A Van Steenwyk, Robert M Nowierski, Jennifer L Vollmer, Eric Lane, Earl Chilton, Patrick L Burch, Phil E. Cowan, Kenneth Zimmerman, Christopher P Dionigi
      Abstract: BACKGROUNDInvasive species are one of the greatest economic and ecological threats to agriculture and natural areas in the US and the world. Among the available management tools, biological control provides one of the most economical and long‐term effective strategies for managing widespread and damaging invasive species populations of nearly all taxa.RESULTSIntegrating biological control programs in a more complete integrated pest management approach that utilizes increased information and communication, post‐release monitoring, adaptive management practices, long‐term stewardship strategies, and new and innovative ecological and genetic technologies can greatly improve the effectiveness of biological control. In addition, expanding partnerships among relevant national, regional, and local agencies, as well as academic scientists and land managers, offers far greater opportunities for long‐term success in the suppression of established invasive species.CONCLUSIONSIn this paper we direct our recommendations to federal agencies that oversee, fund, conduct research, and develop classical biological control programs for invasive species. By incorporating these recommendations into adaptive management strategies, private and public land managers will have far greater opportunities for long‐term success in suppression of established invasive species.
      PubDate: 2016-06-29T02:20:36.694577-05:
      DOI: 10.1002/ps.4347
  • Predation by generalist arthropod predators on Apolygus lucorum
           (Hemiptera: Miridae): molecular gut‐content analysis and field‐cage
    • Authors: Jinhua Li; Fan Yang, Qian Wang, Hongsheng Pan, Haibin Yuan, Yanhui Lu
      Abstract: BACKGROUNDThe mirid bug Apolygus lucorum (Meyer‐Dür) is a principal pest of cotton that also causes great damage to many other crops in China. A study was conducted to assess the mortality of A. lucorum from generalist arthropod predators using both molecular methods and a field‐cage trial. The species‐specific primer pair for the detection of A. lucorum tissues in predators was designed according to the sequences of the cytochrome oxidase subunit I (COI) gene.RESULTSA total of 2096 generalist predators that consisted of ladybeetles, lacewings and spiders were collected, and A. lucorum remains were detected using the designed primers. Only 1.6% of these predators contained A. lucorum DNA, with the highest positive proportion (6.1%) for Harmonia axyridis larvae. In the field‐cage experiment, the daily predation rates of 2nd instar A. lucorum nymphs by H. axyridis adults and larvae were 4.7% and 5.2%, respectively.CONCLUSIONSThe overall low positive proportion of generalist predators with A. lucorum DNA detected using the molecular method combined with the low predation rate in the field‐cage experiment indicated that the primary generalist predators likely had a limited role in the suppression of A. lucorum in the field.
      PubDate: 2016-06-28T03:40:20.209566-05:
      DOI: 10.1002/ps.4346
  • Insecticide ADME for Support of Early Phase Discovery: Combining Classical
           and Modern Techniques
    • Authors: Michael D. David
      Abstract: The two factors which determine an insecticide's potency are its binding to a target site (intrinsic activity) and the ability of its active form to reach the target site (bioavailability). Bioavailability is dictated by the compound's stability and transport kinetics, which are determined by both physical and biochemical characteristics. At BASF Global Insecticide Research, we characterize bioavailability in early research with an ADME (Absorption, Distribution, Metabolism, and Excretion) approach, combining classical and modern techniques. For biochemical assessment of metabolism, we purify native insect enzymes using classical techniques, and recombinantly express individual insect enzymes which are known to be relevant in insecticide metabolism and resistance. For analytical characterization of an experimental insecticide and its metabolites, we conduct classical radiotracer translocation studies when a radiolabel is available. In discovery, where typically no radiolabel has been synthesized, we utilize modern high‐resolution mass spectrometry to probe complex systems for the test compounds and its metabolites. By using these combined approaches, we can rapidly compare the ADME properties of sets of new experimental insecticides and aid in the design of structures with an improved potential to advance in the research pipeline.
      PubDate: 2016-06-27T03:45:34.207794-05:
      DOI: 10.1002/ps.4345
  • Potential risk levels of invasive Neoleucinodes elegantalis (small tomato
           borer) in areas optimal for open field Solanum lycopersicum (tomato)
           cultivation in the present and under predicted climate change
    • Authors: Ricardo Siqueira da Silva; Lalit Kumar, Farzin Shabani, Marcelo Coutinho Picanço
      Abstract: BACKGROUNDNeoleucinodes 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.RESULTSLarge 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.CONCLUSIONThe 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: BACKGROUNDVolunteer 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.RESULTSCropping 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%.CONCLUSIONCrop 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: BACKGROUNDBed 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.RESULTSWe 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.CONCLUSIONBed 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
    • Authors: Shun‐Fan Wu; Xi‐Chao Mu, Yao‐Xue Dong, Li‐Xiang Wang, Qi Wei, Cong‐Fen Gao
      Abstract: BACKGROUNDGlutamate‐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.RESULTSIn 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.CONCLUSIONThis 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
    • Authors: Elisa Heuser; Stefan Fischer, Rene Ryll, Anne Mayer‐Scholl, Donata Hoffmann, Carina Spahr, Christian Imholt, Dewi Murni Alfa, Andreas Fröhlich, Dörte Lüschow, Reimar Johne, Bernhard Ehlers, Sandra Essbauer, Karsten Nöckler, Rainer G. Ulrich
      Abstract: BACKGROUNDThe 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).RESULTSLeptospira 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.CONCLUSIONSStudy 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: BACKGROUNDThe 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.RESULTSEven 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.CONCLUSIONSApproaches and tools are proposed for standardizable and transparent refinements in regulatory risk assessments on landscape level.
      PubDate: 2016-06-14T08:25:28.81018-05:0
      DOI: 10.1002/ps.4338
  • RNAi‐based gene silencing through dsRNA injection or ingestion against
    • Authors: Katterinne Prentice; Olivier Christiaens, Ine Pertry, Ana Bailey, Chuck Niblett, Marc Ghislain, Godelieve Gheysen, Guy Smagghe
      Abstract: BACKGROUNDRNA 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.RESULTSHere 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.CONCLUSIONWe 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
    • Authors: Ljiljana Krstin; Zorana Katanić, Marin Ježić, Igor Poljak, Lucija Nuskern, Ivana Matković, Marilena Idžojtić, Mirna Ćurković‐Perica
      Abstract: BACKGROUNDChestnut 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.RESULTSTwo 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.CONCLUSIONSome 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: BACKGROUNDThe 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.RESULTSThe 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.CONCLUSIONSRapid 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
    • Authors: Ingrid K. A. Zwertvaegher; Inge Van Daele, Peter Verheesen, Marnix Peferoen, David Nuyttens
      Abstract: BACKGROUNDRainfall 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.RESULTSThe 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).CONCLUSIONFuture 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
    • Authors: Thomas Lopes; Séverin Hatt, Qinxuan Xu, Julian Chen, Yong Liu, Frédéric Francis
      Abstract: BACKGROUNDWheat 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.RESULTSFifty 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.CONCLUSIONThese 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
    • Authors: O Frikha‐Gargouri; D Ben Abdallah, I Ghorbel, I Charfeddine, L Jlaiel, MA Triki, S Tounsi
      Abstract: BACKGROUNDThis 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.RESULTSB. 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.CONCLUSIONB. 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
  • Evolution of resistance to pyrethroid insecticides in Musca domestica
    • Authors: Jeffrey G. Scott
      Abstract: BACKGROUNDHouse 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).RESULTSHouse 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.CONCLUSIONSThe 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
  • 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: BACKGROUNDEffective 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.RESULTSVariation 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.CONCLUSIONPermethrin‐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
  • Issue Information - Aims and Scope
    • Pages: 2009 - 2009
      PubDate: 2016-10-04T05:42:56.242284-05:
      DOI: 10.1002/ps.4137
  • Issue Information - Info Page
    • Pages: 2010 - 2010
      PubDate: 2016-10-04T05:42:57.77796-05:0
      DOI: 10.1002/ps.4138
  • Issue Information - ToC
    • Pages: 2011 - 2012
      PubDate: 2016-10-04T05:43:01.206491-05:
      DOI: 10.1002/ps.4139
  • Strigolactones and parasitic weed management 50 years after the discovery
           of the first natural strigolactone strigol: status and outlook
    • Authors: Claudio Screpanti; Koichi Yoneyama, Harro J Bouwmeester
      Pages: 2013 - 2015
      PubDate: 2016-10-04T05:42:55.660569-05:
      DOI: 10.1002/ps.4436
  • Suicidal germination for parasitic weed control
    • Authors: Binne Zwanenburg; Alinanuswe S Mwakaboko, Chinnaswamy Kannan
      Pages: 2016 - 2025
      Abstract: Parasitic weeds of the genera Striga and Orobanche spp. cause severe yield losses in agriculture, especially in developing countries and the Mediterranean. Seeds of these weeds germinate by a chemical signal exuded by the roots of host plants. The radicle thus produced attaches to the root of the host plant, which can then supply nutrients to the parasite. There is an urgent need to control these weeds to ensure better agricultural production. The naturally occurring chemical signals are strigolactones (SLs), e.g. strigol and orobanchol. One option to control these weeds involves the use of SLs as suicidal germination agents, where germination takes place in the absence of a host. Owing to the lack of nutrients, the germinated seeds will die. The structure of natural SLs is too complex to allow multigram synthesis. Therefore, SL analogues are developed for this purpose. Examples are GR24 and Nijmegen-1. In this paper, the SL analogues Nijmegen-1 and Nijmegen-1 Me were applied in the field as suicidal germination agents. Both SL analogues were formulated using an appropriate EC-approved emulsifier (polyoxyethylene sorbitol hexaoleate) and applied to tobacco (Nicotiana tabacum L.) fields infested by Orobanche ramosa L. (hemp broomrape), following a strict protocol. Four out of 12 trials showed a reduction in broomrape of ≥95%, two trials were negative, two showed a moderate result, one was unclear and in three cases there was no Orobanche problem in the year of the trials. The trial plots were ca 2000 m2; half of that area was treated with stimulant emulsion, the other half was not treated. The optimal amount of stimulant was 6.25 g ha−1. A preconditioning prior to the treatment was a prerequisite for a successful trial. In conclusion, the suicidal germination approach to reducing O. ramosa in tobacco fields using formulated SL analogues was successful. Two other options for weed control are discussed: deactivation of stimulants prior to action and biocontrol by Fusarium oxysporum. © 2016 Society of Chemical Industry
      PubDate: 2016-02-15T04:17:00.015908-05:
      DOI: 10.1002/ps.4222
  • Strigolactones: how far is their commercial use for agricultural
    • Authors: Maurizio Vurro; Cristina Prandi, Francesca Baroccio
      Pages: 2026 - 2034
      Abstract: Strigolactones are a class of natural and synthetic compounds that in the past decade have been exciting the scientific community not only for their intriguing biological properties but also for their potential applications in agriculture. These applications range from their use as hormones to modify and/or manage plant architecture, to their use as stimulants to induce seed germination of parasitic weeds and thus control their infestation by a reduced seed bank, to their use as ‘biostimulants’ of plant root colonisation by arbuscular mycorrhizal fungi, improving plant nutritional capabilities, to other still unknown effects on microbial soil communities. More recently, these compounds have also been attracting the interest of agrochemical companies. In spite of their biological attractiveness, practical applications are still greatly hampered by the low product yields obtainable by plant root exudates, by the costs of their synthesis, by the lack of knowledge of their off-target effects and by the not yet specified or properly identified legislation that could regulate the use of these compounds, depending on the agricultural purposes. The aim of this article is to discuss, in the light of current knowledge, the different scenarios that might play out in the near future with regard to the practical application of strigolactones. © 2016 Society of Chemical Industry
      PubDate: 2016-03-15T06:11:48.638795-05:
      DOI: 10.1002/ps.4254
  • Practicality of the suicidal germination approach for controlling Striga
    • Authors: Hiroaki Samejima; Abdel Gabar Babiker, Hirosato Takikawa, Mitsuru Sasaki, Yukihiro Sugimoto
      Pages: 2035 - 2042
      Abstract: BACKGROUNDPurple witchweed (Striga hermonthica), Orobanchaceae, is an obligate root-parasitic weed of important cereal crops. The parasite is a copious seed producer, and a huge seed bank develops soon after the onset of the initial infestation. To germinate, a Striga seed requires a pretreatment in a moist warm environment and a subsequent exposure to an exogenous stimulant. One approach to reduce the seed bank is artificially to induce germination of the seeds in the absence of or away from the host roots. A newly developed germination stimulant for S. hermonthica, designated as T-010, was evaluated for efficacy in greenhouse and field experiments under artificial Striga infestation.RESULTST-010 displayed germination-inducing activity in soil. Formulated T-010 applied at 0.1, 1 and 10 kg ai ha−1 to potted soil containing S. hermonthica seeds, previously conditioned by judicious irrigation, reduced Striga emergence by 94–100%. Results of a field trial showed that formulated T-010, at the same rates as for the pot experiment, delayed and reduced Striga emergence by 33% and increased sorghum shoot and head dry weight by 18.7–40.2% and 187–241% respectively.CONCLUSIONThese findings demonstrated, for the first time, the technical feasibility of suicidal germination for controlling S. hermonthica. Optimising structure, formulation and application protocol of germination stimulants should be the main goal for further improvement of the technology. © 2016 Society of Chemical Industry
      PubDate: 2016-02-04T05:11:31.377164-05:
      DOI: 10.1002/ps.4215
  • Parasitic weed management by using strigolactone-degrading fungi
    • Authors: Angela Boari; Biancamaria Ciasca, Rocío Pineda-Martos, Veronica MT Lattanzio, Koichi Yoneyama, Maurizio Vurro
      Pages: 2043 - 2047
      Abstract: BACKGROUNDSeed germination is a key phase of the parasitic plant life cycle that is stimulated by the secondary metabolites, mainly strigolactones (SLs), secreted by the host roots. Interventions during this stage would be particularly suitable for parasitic weed management practices, as blocking these chemical signals would prevent seed germination and thus parasite attack. Four fungal strains with different ecological functions were considered for their possible ability to metabolise SLs: Fusarium oxysporum and F. solani, biocontrol agents of Phelipanche ramosa; Trichoderma harzianum, a potential biopesticide; Botrytis cinerea, a phytopathogenic fungus. Four different SLs [the natural strigol, 5-deoxystrigol (5DS) and 4-deoxyorobanchol (4DO), and the synthetic analogue GR24] were added to fungal cultures, followed by determination of the SL content by liquid chromatography–tandem mass spectrometry.RESULTSDifferences were observed among microorganisms, treatments and SLs used. T. harzianum and F. oxysporum were the most capable of reducing the SL content; considering the whole set of fungi used, 5DS and 4DO proved to be the most degradable SLs.CONCLUSIONSBeneficial microscopic fungi could differently be used for biocontrolling parasitic weeds, acting as a ‘physiological’ barrier, by preventing the germination of their seeds through the ability to biotransform the stimulatory signals. © 2016 Society of Chemical Industry
      PubDate: 2016-02-09T04:45:14.257405-05:
      DOI: 10.1002/ps.4226
  • Chemical modification of a phenoxyfuranone-type strigolactone mimic for
           selective effects on rice tillering or Striga hermonthica seed germination
    • Authors: Ikuo Takahashi; Kosuke Fukui, Tadao Asami
      Pages: 2048 - 2053
      Abstract: BACKGROUNDWe 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.RESULTSBoth assays showed that the substituent position affected debranone 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.CONCLUSIONThese 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. © 2016 Society of Chemical Industry
      PubDate: 2016-04-05T03:55:42.355445-05:
      DOI: 10.1002/ps.4265
  • Simplified strigolactams as potent analogues of strigolactones for the
           seed germination induction of Orobanche cumana Wallr.
    • Authors: Alexandre Lumbroso; Emmanuelle Villedieu-Percheron, Didier Zurwerra, Claudio Screpanti, Mathilde Lachia, Pierre-Yves Dakas, Laure Castelli, Verity Paul, Hanno Christian Wolf, Danielle Sayer, Andreas Beck, Stefano Rendine, Raymonde Fonné-Pfister, Alain De Mesmaeker
      Pages: 2054 - 2068
      Abstract: BACKGROUNDStrigolactones play an important role in the rhizosphere as signalling 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.RESULTSWe 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.CONCLUSIONSThe novel strigolactam derivatives described here compare favourably with the corresponding GR-28 strigolactones in terms of biological activity and physicochemical properties. However, we believe strigolactone and strigolactam derivatives require further structural optimisation to improve their soil persistence to demonstrate a potential for agronomical applications. © 2016 Society of Chemical Industry
      PubDate: 2016-04-18T08:30:30.810549-05:
      DOI: 10.1002/ps.4268
  • Phthalimide-derived strigolactone mimics as germinating agents for seeds
           of parasitic weeds
    • Authors: Antonio Cala; Kala Ghooray, Mónica Fernández-Aparicio, José MG Molinillo, Juan CG Galindo, Diego Rubiales, Francisco A Macías
      Pages: 2069 - 2081
      Abstract: BACKGROUNDBroomrapes attack important crops, cause severe yield losses and 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 analogues of germination-inducing factors may constitute a cheap and feasible strategy to control the seed bank. These compounds should be easy and cheap to synthesise, as this will allow their mass production. The aim of this work is to obtain new synthethic germinating agents.RESULTSNineteen N-substituted phthalimides containing a butenolide ring and different substituents in the aromatic ring were synthesised. 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 analogue GR24 used as a positive control. These 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.CONCLUSIONSThe synthesis was carried out in a 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. © 2016 Society of Chemical Industry
      PubDate: 2016-06-24T03:32:09.373155-05:
      DOI: 10.1002/ps.4323
  • Effects of selected herbicides and fungicides on growth, sporulation and
           conidial germination of entomopathogenic fungus Beauveria bassiana
    • Authors: Franci A Celar; Katarina Kos
      Pages: 2110 - 2117
      Abstract: BACKGROUNDThe in vitro fungicidal effects of six commonly used fungicides, namely fluazinam, propineb, copper(II) hydroxide, metiram, chlorothalonil and mancozeb, and herbicides, namely isoxaflutole, fluazifop-P-butyl, flurochloridone, foramsulfuron, pendimethalin and prosulfocarb, on mycelial growth, sporulation and conidial germination of entomopathogenic fungus Beauveria bassiana (ATCC 74040) were investigated. Mycelial growth rates and sporulation at 15 and 25 °C were evaluated on PDA plates containing 100, 75, 50, 25, 12.5, 6.25 and 0% of the recommended application rate of each pesticide. The tested pesticides were classified in four scoring categories based on reduction in mycelial growth and sporulation.RESULTSAll pesticides, herbicides and fungicides tested had fungistatic effects of varying intensity, depending on their rate in the medium, on B. bassiana. The most inhibitory herbicides were flurochloridone and prosulfocarb, and fluazinam and copper(II) hydroxide were most inhibitory among the fungicides, while the least inhibitory were isoxaflutole and chlorothalonil. Sporulation and conidial germination of B. bassiana were significantly inhibited by all tested pesticides compared with the control treatment. Flurochloridone, foramsulfuron, prosulfocarb and copper(II) hydroxide inhibited sporulation entirely at 100% rate (99–100% inhibition), and the lowest inhibition was shown by fluazifop-P-butyl (22%) and metiram (33%). At 100% dosage, all herbicides in the test showed a high inhibitory effect on conidial germination. Conidial germination inhibition ranged from 82% with isoxaflutole to 100% with fluorochloridone, pendimethalin and prosulfocarb. At 200% dosage, inhibition rates even increased (96–100%).CONCLUSIONSAll 12 pesticides tested had a fungistatic effect on B. bassiana of varying intensity, depending on the pesticide and its concentration. B. bassiana is highly affected by some herbicides and fungicides even at very low rates. Flurochloridone, foramsulfuron, prosulfocarb and copper(II) hydroxide stopped sporulation. Of all tested pesticides, isoxaflutole, fluazifop-P-butyl and chlorothalonil showed the least adverse effects and therefore probably could be compatible with B. bassiana in the field. © 2016 Society of Chemical Industry
      PubDate: 2016-02-29T09:03:02.537282-05:
      DOI: 10.1002/ps.4240
  • Insecticidal potency of RNAi-based catalase knockdown in Rhynchophorus
           ferrugineus (Oliver) (Coleoptera: Curculionidae)
    • Authors: Hassan Al-Ayedh; Muhammad Rizwan-ul-Haq, Abid Hussain, Ahmed M Aljabr
      Pages: 2118 - 2127
      Abstract: BACKGROUNDPalm trees around the world are prone to notorious Rhynchophorus ferrugineus, which causes heavy losses of palm plantations. In Middle Eastern countries, this pest is a major threat to date palm orchards. Conventional pest control measures with the major share of synthetic insecticides have resulted in insect resistance and environmental issues. Therefore, in order to explore better alternatives, the RNAi approach was employed to knock down the catalase gene in fifth and tenth larval instars with different dsRNA application methods, and their insecticidal potency was studied.RESULTSdsRNA of 444 bp was prepared to knock down catalase in R. ferrugineus. Out of the three dsRNA application methods, dsRNA injection into larvae was the most effective, followed by dsRNA application by artificial feeding. Both methods resulted in significant catalase knockdown in various tissues, especially the midgut. As a result, the highest growth inhibition of 123.49 and 103.47% and larval mortality of 80 and 40% were observed in fifth-instar larvae, whereas larval growth inhibition remained at 86.83 and 69.08% with larval mortality at 30 and 10% in tenth-instar larvae after dsRNA injection and artificial diet treatment. The topical application method was the least efficient, with the lowest larval growth inhibition of 57.23 and 45.61% and 0% mortality in fifth- and tenth-instar larvae. Generally, better results were noted at the high dsRNA dose of 5 µL.CONCLUSIONCatalase enzyme is found in most insect body tissues, and thus its dsRNA can cause broad-scale gene knockdown within the insect body, depending upon the application method. Significant larval mortality and growth inhibition after catalase knockdown in R. ferrugineus confirms its insecticidal potency and suggests a bright future for RNAi-based bioinsecticides in pest control. © 2016 Society of Chemical Industry
      PubDate: 2016-03-01T04:18:51.046779-05:
      DOI: 10.1002/ps.4242
  • Development of a rapid and high-throughput molecular method for detecting
           the F200Y mutant genotype in benzimidazole-resistant isolates of Fusarium
    • Authors: Yabing Duan; Ying Yang, Tao Li, Donglei Zhao, Junhong Cao, Yiyuan Shi, Jianxin Wang, Mingguo Zhou
      Pages: 2128 - 2135
      Abstract: BackgroundThe point mutation at codon 200 (TTCTAC, F200Y) of the β2-tubulin gene confers resistance to benzimidazole fungicide in Fusarium asiaticum. These isolates with this mutation have been detected mainly by determining the minimum inhibitory concentration (MIC) of fungicides, which is always time consuming, tedious and inefficient.ResultsA visual, rapid and efficient method with high specificity was developed, based on loop-mediated isothermal amplification (LAMP). Six sets of LAMP primers were designed, and one set was optimised specifically to distinguish the F200Y mutant genotype. With the optimal LAMP primers, concentrations of LAMP components were optimised. The optimal reaction conditions were 57–64 °C for 75 min. The feasibility of the LAMP assay for detection of the F200Y mutant genotype of F. asiaticum was demonstrated by assaying diseased wheat spikelets that were artificially inoculated in the field.ConclusionThe new LAMP assay had good specificity, sensitivity, stability and repeatability. It will be useful for assessing the risk of F. asiaticum populations with carbendazim resistance developing in the field, and will also provide important reference data for integrated control of Fusarium head blight caused by F. asiaticum. © 2016 Society of Chemical Industry
      PubDate: 2016-03-03T07:55:48.645149-05:
      DOI: 10.1002/ps.4243
  • Development of a CO2-releasing coformulation based on starch,
           Saccharomyces cerevisiae and Beauveria bassiana attractive towards western
           corn rootworm larvae
    • Authors: Marina Vemmer; Mario Schumann, Wilhelm Beitzen-Heineke, Bryan W French, Stefan Vidal, Anant V Patel
      Pages: 2136 - 2145
      Abstract: BACKGROUNDCO2 is known as an attractant for many soil-dwelling pests. To implement an attract-and-kill strategy for soil pest control, CO2-emitting formulations need to be developed. The aim of the present work was to develop a slow-release bead system in order to bridge the gap between application and hatching of western corn rootworm larvae.RESULTSWe compared different Ca-alginate beads containing Saccharomyces cerevisiae for their potential to release CO2 over a period of several weeks. The addition of starch improved CO2 release, resulting in significantly higher CO2 concentrations in soil for at least 4 weeks. The missing amylase activity was compensated for either by microorganisms present in the soil or by coencapsulation of Beauveria bassiana. Formulations containing S. cerevisiae, starch and B. bassiana were attractive for western corn rootworm larvae within the first 4 h following exposure; however, when considering the whole testing period, the maize root systems remained more attractive for the larvae.CONCLUSIONCoencapsulation of S. cerevisiae, starch and B. bassiana is a promising approach for the development of attractive formulations for soil applications. For biological control strategies, the attractiveness needs to be increased by phagostimuli to extend contact between larvae and the entomopathogenic fungus growing out of these formulations. © 2016 Society of Chemical Industry
      PubDate: 2016-03-03T06:45:06.533942-05:
      DOI: 10.1002/ps.4245
  • Allelobiosis in the interference of allelopathic wheat with weeds
    • Authors: Yong-Hua Li; Zhi-Chao Xia, Chui-Hua Kong
      Pages: 2146 - 2153
      Abstract: BACKGROUNDPlants may chemically affect the performance of neighbouring plants through allelopathy, allelobiosis or both. In spite of increasing knowledge about allelobiosis, defined as the signalling interactions mediated by non-toxic chemicals involved in plant–plant interactions, the phenomenon has received relatively little attention in the scientific literature. This study examined the role of allelobiosis in the interference of allelopathic wheat with weeds.RESULTSAllelopathic wheat inhibited the growth of five weed species tested, and the allelochemical (2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one) production of wheat was elicited in the presence of these weeds, even with root segregation. The inhibition and allelochemical levels varied greatly with the mixed species density. Increased inhibition and allelochemical levels occurred at low and medium densities but declined at high densities. All the root exudates and their components of jasmonic acid and salicylic acid from five weeds stimulated allelochemical production. Furthermore, jasmonic acid and salicylic acid were found in plants, root exudates and rhizosphere soils, regardless of weed species, indicating their participation in the signalling interactions defined as allelobiosis.CONCLUSIONThrough root-secreted chemical signals, allelopathic wheat can detect competing weeds and respond by increased allelochemical levels to inhibit them, providing an advantage for its own growth. Allelopathy and allelobiosis are two probably inseparable processes that occur together in wheat–weed chemical interactions. © 2016 Society of Chemical Industry
      PubDate: 2016-03-02T03:15:45.381858-05:
      DOI: 10.1002/ps.4246
  • RNA interference of cytochrome P450 CYP6F subfamily genes affects
           susceptibility to different insecticides in Locusta migratoria
    • Authors: Yanqiong Guo; Haihua Wu, Xueyao Zhang, Enbo Ma, Yaping Guo, Kun Yan Zhu, Jianzhen Zhang
      Pages: 2154 - 2165
      Abstract: BACKGROUNDMany insect cytochrome P450s (CYPs) play critical roles in detoxification of insecticides. The CYP6 family is unique to the class Insecta, and its biochemical function has essentially been associated with the metabolism of xenobiotics. In this study, we sequenced and characterised the full-length cDNAs of five CYP genes from Locusta migratoria, a highly destructive agricultural pest worldwide.RESULTSThe five genes were predominantly expressed in brain, guts, fat bodies or Malpighian tubules. CYP6FE1, CYP6FF1 and CYP6FG1 were expressed at higher levels in fourth-instar nymphs than in other developmental stages. CYPFD2 is specifically expressed in adults, whereas CYP6FD1, CYP6FD2 and CYP6FE1 showed significantly lower expression in eggs than in other developmental stages. Deltamethrin suppressed CYP6FD1 expression in third-instar nymphs and upregulated the expression level of CYP6FD2, CYP6FF1 and CYP6FG1 at the dose of LD10. Efficient RNA interference-mediated gene silencing was established for four of the five CYP genes. Silencing of CYP6FF1 increased the nymphal mortality from 23 to 50% in response to deltamethrin. Silencing of CYP6FD2 and CYP6FE1 increased the nymphal mortality from 32 to 72 and 66%, respectively, to carbaryl.CONCLUSIONThree of the four CYP6F subfamily genes in L. migratoria were associated with the detoxification of deltamethrin or carbaryl. The role of CYPs in insecticide detoxification appears to be both gene and insecticide specific. © 2016 Society of Chemical Industry
      PubDate: 2016-03-15T05:50:46.71771-05:0
      DOI: 10.1002/ps.4248
  • Binding of imidacloprid, thiamethoxam and N-desmethylthiamethoxam to
           nicotinic receptors of Myzus persicae: pharmacological profiling using
           neonicotinoids, natural agonists and antagonists
    • Authors: Hartmut Kayser; Katrin Lehmann, Marilyne Gomes, Wolfgang Schleicher, Karin Dotzauer, Margarethe Moron, Peter Maienfisch
      Pages: 2166 - 2175
      Abstract: BACKGROUNDThe increasing structural diversity of the neonicotinoid class of insecticides presently used in crop protection calls for a more detailed analysis of their mode of action at their cellular targets, the nicotinic acetylcholine receptors.RESULTSComparative radioligand binding studies using membranes of Myzus persicae (Sulzer) and representatives of the chloropyridyl subclass (imidacloprid), the chlorothiazolyl subclass (thiamethoxam), the tetrahydrofuranyl subclass (dinotefuran), as well as the novel sulfoximine type (sulfoxaflor), which is not a neonicotinoid, reveal significant differences in the number of binding sites, the displacing potencies and the mode of binding interference. Furthermore, the mode of interaction of [3H]thiamethoxam and the nicotinic antagonists methyllycaconitine and dihydro-β-erythroidine is unique, with Hill values of >1, clearly different to the values of around unity for [3H]imidacloprid and [3H]N-desmethylthiamethoxam. The interaction of [3H]N-desmethylthiamethoxam with the agonist (−)nicotine is also characterised by a Hill value of >1.CONCLUSIONSThere is no single conserved site or mode of binding of neonicotinoids and related nicotinic ligands to their target receptor, but a variety of binding pockets depending on the combination of receptor subunits, the receptor subtype, its functional state, as well as the structural flexibility of both the binding pockets and the ligands. © 2016 Society of Chemical Industry
      PubDate: 2016-03-07T05:53:00.27786-05:0
      DOI: 10.1002/ps.4249
  • The discovery of a novel antagonist – Manduca sexta allatotropin
           analogue – as an insect midgut active ion transport inhibitor
    • Authors: Xi-le Deng; Zhen-peng Kai, Mary E Chamberlin, Frank M Horodyski, Xin-ling Yang
      Pages: 2176 - 2180
      Abstract: BACKGROUNDThe midgut is an important site for both nutrient absorption and ionic regulation in lepidopteran larvae, major pests in agriculture. The larval lepidopteran midgut has become a potent insecticide target over the past few decades. Recent studies have shown that an insect neuropeptide, Manduca sexta allatotropin (Manse-AT), exhibits inhibition of active ion transport (AIT) across the larval midgut epithelium. The full characteristic of the AIT inhibition capacity of Manse-AT is essential to assay. In this study, AIT inhibition across the M. sexta midgut by Manse-AT and its analogues in a range of concentrations was assayed. The structure–activity relationship of Manse-AT was also studied by truncated and alanine-replacement strategies.RESULTSOur results identified three residues, Thr4, Arg6 and Phe8, as the most important components for activity on the midgut. Replacement of Glu1, Met2 and Met3 reduced the potency of the analogues. The conservative substitution of Gly7 with alanine had little effect on the potency of the analogues. We demonstrated for the first time that Manse-AT (10–13) behaves as a potent antagonist in vitro on active ion transport across the epithelium of the posterior midgut in M. sexta.CONCLUSIONStructure–activity studies of Manse-AT are useful in developing lead compounds for the design and testing of synthetic antagonists, ultimately to develop potent and specific pest control strategies. Manse-AT (10–13) has been discovered as the first Manse-AT antagonist, with a significant effect and a short sequence compared with other insect neuropeptides. It may be a new potential pest control agent in the future. © 2016 Society of Chemical Industry
      PubDate: 2016-03-22T02:55:24.838569-05:
      DOI: 10.1002/ps.4251
  • 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 B dos Santos, Judith K Brown
      Pages: 2181 - 2187
      Abstract: BACKGROUNDBemisia 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 screenhouse studies were carried out to investigate the durability of this putative and unprecedented adaptation to a grass host.RESULTSAnalysis 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 first and second leaves of maize, but were also able to colonise 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 screenhouse developed from egg to adulthood in 28.6 ± 0.2 days.CONCLUSIONThis 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. © 2016 Society of Chemical Industry
      PubDate: 2016-03-31T03:16:22.320419-05:
      DOI: 10.1002/ps.4259
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