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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  [1616 journals]
  • Methods for evaluating leaf surface free energy and polarity having
           accounted for surface roughness
    • Authors: Justin J Nairn; W Alison Forster
      Abstract: BACKGROUNDLeaf surfaces can have similar wettability, while their roughness and polarity may be very different. This may affect agrochemical bioefficacy, hence there is a need to characterise leaf surface polarity and roughness separately. This paper reviews established surface evaluation techniques and then uses a comprehensive dataset of static contact angles (12 chemical solutions on 15 different species) to compare and contrast them for their ability to characterise leaf surface polarity in isolation from roughness.RESULTSMany techniques were severely limited when applied to leaf surfaces. A failing of the surface free energy (SFE) concept is that both physical and chemical properties affect the SFE. Additionally, whilst the leaf surface chemistry does not change, the SFE values generated are dependent on the chemical properties of the probe solution employed.CONCLUSIONSThe wetting tension–dielectric (WTD) method stands out due to its ability to isolate and quantify leaf surface roughness and polarity. A novel (WTD) roughness correction factor is proposed to improve SFE determination. The strong correlation between leaf polarity and leaf wettability for polar solutions (such as water) makes the WTD method a valuable tool for the evaluation of leaf surface-droplet behaviour and the advancement of agrochemical spray formulation technologies. © 2017 Society of Chemical Industry
      PubDate: 2017-03-20T23:55:47.771507-05:
      DOI: 10.1002/ps.4551
       
  • Positive and normative modeling for Palmer amaranth control and herbicide
           resistance management
    • Authors: George B Frisvold; Muthukumar V Bagavathiannan, Jason K Norsworthy
      Abstract: BACKGROUNDDynamic optimization models are normative; they solve for what growers ‘ought to do’ to maximize some objective, such as long-run profits. While valuable for research, such models are difficult to solve computationally, limiting their applicability to grower resistance management education. While discussing properties of normative models in general, this study presents results of a specific positive model of herbicide resistance management, applied to Palmer amaranth control on a representative cotton farm. This positive model compares a proactive resistance management strategy to a reactive strategy with lower short-run costs, but greater risk of herbicide resistance developing.RESULTSThe proactive strategy can pay for itself within 1–4 years, with a yield advantage of 4% or less if the yield advantage begins within 1–2 years of adoption. Whether the proactive strategy is preferable is sensitive to resistance onset and yield losses, but less sensitive to cotton prices or baseline yields. Industry rebates to encourage residual herbicide use (to delay resistance to post-emergence treatments) may be too small to alter grower behavior or they may be paid to growers who would have used residuals anyway. Rebates change grower behavior over a relatively narrow range of model parameters. The size of rebates needed to induce a grower to adopt the proactive strategy declines significantly if growers extend their planning horizon from 1 year to 3–4 years.CONCLUSIONSWhether proactive resistance management is more profitable than a reactive strategy is more sensitive to biological parameters than economic ones. Simulation results suggest growers with longer time horizons (perhaps younger ones) would be more responsive to rebate programs. More empirical work is needed to determine how much rebates increase residual use above what would occur without them. © 2017 Society of Chemical Industry
      PubDate: 2017-03-20T23:55:35.628405-05:
      DOI: 10.1002/ps.4537
       
  • Migratory flight behaviour of the pollen beetle Meligethes aeneus
    • Authors: Alice L Mauchline; Samantha M Cook, Wilf Powell, Jason W Chapman, Juliet L Osborne
      Abstract: BACKGROUNDThe field ecology of the pollen beetle Meligethes aeneus and its damaging effects on oilseed rape crops are well understood. However, the flight behaviour of M. aeneus, in particular the drivers for migratory movements across the landscape, is not well studied. We combined three established methodologies – suction traps, vertical-looking radar and high-altitude aerial netting – to demonstrate that M. aeneus flies at a range of altitudes at different points during its active season.RESULTSBy linking evidence of high-altitude mass migration with immigration of pollen beetles into oilseed rape fields, we were able to ‘ground-truth’ the results to characterise the seasonal movements of this pest across the landscape.CONCLUSIONWe demonstrate that this novel combination of methodologies can advance our understanding of the population movements of pollen beetles and could provide an opportunity to develop predictive models to estimate the severity and timing of pest outbreaks. © 2017 The
      Authors . Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
      PubDate: 2017-03-20T23:51:18.746668-05:
      DOI: 10.1002/ps.4550
       
  • A systematic review of the literature reveals trends and gaps in
           integrated pest management studies conducted in the USA
    • Authors: Stephen L Young
      Abstract: Integrated pest management (IPM) is a broad-based approach for addressing pests that negatively affect human and environmental health and economic profitability. Weeds, insects, and disease-causing pathogens (diseases) are the pests most often associated with IPM. A systematic review, widely used in other scientific disciplines, was employed to determine the most commonly studied IPM topics and summarize the reasons for these trends and the gaps. In a field synopsis of the literature, 1,679 relevant published papers were identified and categorized into one of the following five broad areas: IPM and organic (organic), climate change and pests (climate), rural and urban IPM (rural and urban), next generation education (education), and advanced production systems (technology). Papers were examined in greater detail for at least one of the three main pests in a systematic review. A majority (85%) of IPM papers have been in the area of rural and urban IPM, primarily addressing agriculture (78%). Professionals, land owners, and the general public were the focus of a majority (95%) of IPM papers on education. Technology is an increasing area of focus in the literature. Over the past 40 years, IPM papers have primarily (75%) addressed insects and been limited mostly to rural and urban settings. Climate change, technology, and education specific to pest management studies are increasingly being published and will help broaden the focus that could result in increased adoption and development of IPM.
      PubDate: 2017-03-20T21:30:39.760833-05:
      DOI: 10.1002/ps.4574
       
  • Susceptibility of Insecticide Resistant Bed Bugs (Cimex lectularius) to
           Infection by Fungal Biopesticide
    • Authors: Alexis M. Barbarin; Giovani S. Bellicanta, Jason A. Osborne, Coby Schal, Nina E. Jenkins
      Abstract: BACKGROUNDBed bugs are a public health concern, and their incidence is increasing worldwide. Bed bug infestations are notoriously difficult to eradicate, further exacerbated by widespread resistance to pyrethroid and neonicotinoid insecticides. This study evaluated the efficacy of the newly developed fungal biopesticide, Aprehend™, containing Beauveria bassiana, against insecticide-resistant bed bugs.RESULTSOverall mortality for the Harold Harlan (insecticide-susceptible) strain was high (98-100%) following exposure to Aprehend™ or Suspend SC (deltamethrin). The mean survival times (MSTs) for Harold Harlan bed bugs were 5.1 days for Aprehend™, and 4.8 and 3.0 days for the low and high concentrations of Suspend SC, respectively. All three strains of pyrethroid resistant bed bugs were susceptible to infection by B. bassiana, resulting in MSTs < 6 days (median = 4 days) and >94% overall mortality. Conversely, mortality of the three insecticide resistant strains after exposure to Suspend SC was only 16-40%.CONCLUSIONThese results demonstrate that Aprehend™ is equally effective against insecticide susceptible and resistant bed bugs and could provide pest control operators with a promising new tool for control of bed bugs and insecticide resistance management.
      PubDate: 2017-03-20T21:20:40.01943-05:0
      DOI: 10.1002/ps.4576
       
  • Vectorization of agrochemicals via amino acid carriers: influence of the
           spacer arm structure on the phloem mobility of phenylpyrrole conjugates in
           the Ricinus system
    • Authors: Sophie Marhadour; Hanxiang Wu, Wen Yang, Cécile Marivingt-Mounir, Jean-Louis Bonnemain, Jean-François Chollet
      Abstract: BACKGROUNDExcessive agrochemical use causes significant threats to environmental safety and human health. Reducing pesticide use without reducing yield is necessary for sustainable agriculture. Therefore we developed a vectorization strategy to enhance agrochemical delivery through plant amino acid carriers.RESULTSIn addition to a fenpiclonil conjugate recently described, three new amino acid conjugates were synthesized by coupling fenpiclonil to an L-α-amino acid. Phloem mobility of these conjugates which exhibit different structures of the spacer arm introduced between fenpiclonil and the α-amino acid function, was studied using the Ricinus model. Conjugate L-14 which contains a triazole ring with the shortest amino acid chain showed the best phloem systemicity among the four conjugates. By contrast, removing the triazole ring in the spacer arm did not improve systemicity. L-14 exhibited phloem systemicity at all reported pH values (pHs from 5.0 to 6.5) of the foliar apoplast, while acidic derivatives of fenpiclonil were translocated only at pH values near 5.0.CONCLUSIONThe conjugates were recognized by a pH-dependent transporter system and translocated at distance in the phloem. They exhibited a broader ability to phloem systemicity than fenpiclonil acidic derivatives within the pH value range of the foliar apoplast.
      PubDate: 2017-03-20T21:10:46.836269-05:
      DOI: 10.1002/ps.4575
       
  • EPSPS gene amplification conferring resistance to glyphosate in windmill
           grass (Chloris truncata) in Australia
    • Authors: The D. Ngo; Jenna M. Malone, Peter Boutsalis, Gurjeet Gill, Christopher Preston
      Abstract: BACKGROUNDFive glyphosate resistant populations of Chloris truncata originally collected from New South Wales were compared to one susceptible (S) population from South Australia, Australia to confirm glyphosate resistance and elucidate possible mechanisms of resistance.RESULTSBased on the amounts of glyphosate required to kill 50% of treated plants (LD50), glyphosate resistance (GR) was confirmed in five populations of C. truncata (A536, A528, T27, A534 and A535.1). GR plants were 2.4 to 8.7 fold more resistant and accumulated less shikimate after glyphosate treatment than S plants. There was no difference in glyphosate absorption and translocation between GR and S plants. The EPSPS gene did not contain any point mutation that has previously been associated with resistance to glyphosate. The resistant plants (A528 and A536) contained up to 32-48 more copies of the EPSPS gene than the susceptible plantsCONCLUSIONThis study has identified EPSPS gene amplification contributing to glyphosate resistance in C. truncata. In addition, a Glu-91-Ala mutation within EPSPS was identified that may contribute to glyphosate resistance in this species.
      PubDate: 2017-03-20T00:40:24.014929-05:
      DOI: 10.1002/ps.4573
       
  • Behaviour of bentazon as influenced by water and tillage management in
           rice-growing conditions
    • Authors: Antonio López-Piñeiro; David Peña, Ángel Albarrán, Javier Sánchez-Llerena, José Manuel Rato-Nunes, María Ángeles Rozas
      Abstract: Bentazon is a widely used herbicide in rice agroecosystems that has commonly been found in water resources. To assess how tillage and water regimes affect sorption/desorption, dissipation and leaching of bentazon in Mediterranean rice-growing conditions, field experiments were carried out using tillage and flooding (TF), tillage and sprinkler irrigation (TS), no-tillage and sprinkler irrigation (NTS) and long-term no-tillage and sprinkler irrigation (NTS7). After 3 years, the Kd values in TS were 2.3, 1.6 and 1.7 times lower than the values in NTS7, NTS and TF respectively. Greater sorption of bentazon was related to higher contents in total organic carbon and, although to a lesser extent, in humic acids and dissolved organic carbon. The persistence of bentazon was significantly greater under anaerobic (half-life DT50 = 94.1–135 days) than under aerobic (DT50 = 42.4–91.3 days) incubation conditions for all management regimes. Leaching losses of bentazon were reduced from 78 and 74% in TS and TF to 61 and 62% in NTS7 and NTS respectively. The mid- and long-term implementation of sprinkler irrigation in combination with no-tillage could be considered a management system that is effective at reducing water contamination by bentazon in Mediterranean rice-growing agroecosystems. © 2017 Society of Chemical Industry
      PubDate: 2017-03-17T05:26:00.021809-05:
      DOI: 10.1002/ps.4546
       
  • Evaluation of SmartStax and SmartStax PRO maize against western corn
           rootworm and northern corn rootworm: efficacy and resistance management
    • Authors: Graham P Head; Matthew W Carroll, Sean P Evans, Dwain M Rule, Alan R Willse, Thomas L Clark, Nicholas P Storer, Ronald D Flannagan, Luke W Samuel, Lance J Meinke
      Abstract: BACKGROUNDCases of western corn rootworm (WCR) field-evolved resistance to Cry3Bb1 and other corn rootworm (CRW) control traits have been reported. Pyramid products expressing multiple CRW traits can delay resistance compared to single trait products. We used field studies to assess the pyramid CRW corn products, SmartStax (expressing Cry3Bb1 and Cry34Ab1/Cry35Ab1) and SmartStax PRO (expressing Cry3Bb1, Cry34Ab1/Cry35Ab1 and DvSnf7), at locations with high WCR densities and possible Cry3Bb1 resistance, and to assess the reduction in adult emergence attributable to DvSnf7 and other traits. Insect resistance models were used to assess durability of SmartStax and SmartStax PRO to WCR resistance.RESULTSSmartStax significantly reduced root injury compared to non-CRW-trait controls at all but one location with measurable WCR pressure, while SmartStax PRO significantly reduced root injury at all locations, despite evidence of Cry3Bb1 resistance at some locations. The advantage of SmartStax PRO over SmartStax in reducing root damage was positively correlated with root damage on non-CRW-trait controls. DvSnf7 was estimated to reduce WCR emergence by approximately 80–95%, which modeling indicated will improve durability of Cry3Bb1 and Cry34Ab1/Cry35Ab1 compared to SmartStax.CONCLUSIONThe addition of DvSnf7 in SmartStax PRO can reduce root damage under high WCR densities and prolong Cry3Bb1 and Cry34Ab1/Cry35Ab1 durability. © 2017 Society of Chemical Industry
      PubDate: 2017-03-17T04:05:53.849816-05:
      DOI: 10.1002/ps.4554
       
  • Survey of conspecific herbivore-induced volatiles from apple as possible
           attractants for Pandemis pyrusana (Lepidoptera: Tortricidae)
    • Authors: Valntino Giacomuzzi; James P Mattheis, Esteban Basoalto, Sergio Angeli, Alan L Knight
      Abstract: BACKGROUNDStudies were conducted to identify volatiles released by apple foliage untreated or sprayed with a yeast and from untreated and sprayed foliage with actively feeding larvae of Pandemis pyrusana Kearfott. Field studies then evaluated various combinations of these volatiles when paired with acetic acid as possible adult attractants.RESULTSThe most abundant volatiles released following herbivore feeding were four green leaf volatiles (GLVs) and acetic acid. Nineteen volatiles were found to be released in significantly higher amounts from foliage with herbivore damage than from intact leaves. The combination of yeast followed by herbivore injury increased the levels of methyl salicylate and phenylacetonitrile compared with herbivory alone. Levels of acetic acid released were not significantly different among the four treatments. Only phenylacetonitrile and 2-phenylethanol with acetic acid caught similar and significantly more total and female moths than acetic acid alone. Moth catches with 12 other volatiles plus acetic acid were not significantly higher than with acetic acid alone, and were lower than with acetic acid and 2-phenylethanol.CONCLUSIONThese data show that herbivore injury does not create a unique chemical signal for adults to locate oviposition or rendezvous sites. Instead, moths may cue to the aromatic–acetic acid combination as a nutritional cue to locate sugary resources. © 2017 Society of Chemical Industry
      PubDate: 2017-03-17T03:30:27.557702-05:
      DOI: 10.1002/ps.4548
       
  • Interactions of glyphosate use with farm characteristics and cropping
           patterns in Central Europe
    • Authors: Armin Wiese; Michael Schulte, Ludwig Theuvsen, Horst-Henning Steinmann
      Abstract: BACKGROUNDAlthough glyphosate is the most widely used herbicide in the European Union, little is known about the patterns of its usage in arable farming. Therefore, a nationwide survey of 2026 German farmers was analysed to obtain further knowledge about glyphosate applications in conventional European arable farming. Given its broad range of agri-environmental and farm-type conditions, Germany can be regarded as a suitable study region to represent Central European farming. The growing season 2013/2014 was set as a reference.RESULTSFarmers who participated in the survey employ diverse patterns of glyphosate use. While 23% stated that they did not use glyphosate in the season in question, others applied glyphosate to their total arable area. However, most applications occurred on specific parts of the farm. Application patterns of oilseed rape, winter wheat, maize and sugar beet were studied in detail, and U-shaped distributions of glyphosate use intensity were observed. The effects of farm type and management practices on glyphosate use patterns were mixed in the various crops.CONCLUSIONMotivation for glyphosate use differs widely within the farming community. Agricultural researchers, extension services and policy makers are recommended to mitigate vulnerabilities associated with glyphosate use, such as routine spraying and practices that increase selection pressure for the evolution of glyphosate-resistant weeds. © 2017 Society of Chemical Industry
      PubDate: 2017-03-16T08:35:35.730429-05:
      DOI: 10.1002/ps.4542
       
  • Insights on food webs associated with the South American Tomato Pinworm
    • Authors: Mario Naselli; Antonio Biondi, Giovanna Tropea Garzia, Nicolas Desneux, Agatino Russo, Gaetano Siscaro, Lucia Zappalà
      Abstract: BACKGROUNDComplexity of both natural and managed ecosystems involves various forms of interaction among organisms. Two or more species that exploit the same resource can engage in competitive behaviors, usually referred to as intra-guild interactions. These can be direct, i.e. one species feeds directly upon the competitor (intra-guild predation) or indirect, e.g. when the dominant organism competes for a food source which another organism is feeding on (kleptoparasitism). We investigated the potential for such interactions in a biological model composed by the South American tomato pinworm, Tuta absoluta, and three of its newly associated natural enemies: the zoophytophagous predator Nesidiocoris tenuis, and two idiobiont ectoparasitoids Bracon nigricans, and Necremnus tutae.RESULTSNesidiocoris tenuis showed (i) to scavenge on parasitized T. absoluta larvae, and (ii) to directly attack and feed on larvae of both parasitoid species, although at a higher percentage in the case of N. tutae. In the presence of the host plant the predator reduced the emergence of both B. nigricans and N. tutae adults significantly.CONCLUSIONThis study stresses the ecological success of a generalist predator over indigenous parasitoids attacking an invasive pest. Besides, these findings provide potential elements to better design biological control programs against T. absoluta.
      PubDate: 2017-03-16T03:05:54.154378-05:
      DOI: 10.1002/ps.4562
       
  • Lethal and sublethal effects of pesticides in the management of
           Polyphagotarsonemus latus (Banks) (Acari: Tarsonemidae) on Capsicum annuum
           L.
    • Authors: Mariana O. Breda; José V. Oliveira, Alberto B. Esteves Filho, Douglas R.S. Barbosa, Andrezo A. Santos
      Abstract: BACKGROUNDThe evaluation of lethal and sublethal effects are of great importance for a complete assessment of the total impact of chemical compounds upon pest populations and the development of management strategies. At this study, the lethal and sublethal effects of different synthetic and botanical products were evaluated upon the broad mite, Polyphagotarsonemus latus (Banks), a major pest of Capsicum annuum L and other crops.RESULTSAbamectin presented the highest lethal effect to P. latus, followed by spiromesifen, azadirachtin, the neem oil and the nitrogen fertilizer + citric acid. The sublethal effects of the products were observed by the influence on the mite population growth, affecting the numbers of females, males, larvae, pupae and eggs. Furthermore, negatives instantaneous rate of increase (ri) and repellent effects were observed.CONCLUSIONThe lethal and sublethal effects of abamectin, spiromesifen, azadirachtin and the neem oil significantly affect P. latus population growth as well as present repellence to this mite on C. annuum and should be considered in the integrated pest management of this mite.
      PubDate: 2017-03-15T03:00:47.317358-05:
      DOI: 10.1002/ps.4571
       
  • Assessment of insecticide risk to human health in groundwater in Northern
           China by using the China-PEARL model
    • Authors: Yue Geng; Jing Ma, Ruize Zhou, Ran Jia, Chongjiu Li, Xiaodong Ma
      Abstract: BACKGROUNDInsecticides are extensively used in China and may leach to groundwater, which is used as a source of drinking water in Northern China. However, the risk of insecticide leaching to groundwater and the subsequent risk to human health caused by the consumption of insecticide-contaminated drinking water remain unclear.RESULTSA total of 336 predicted environmental concentrations (PECs) were simulated for 32 commonly-used insecticides, and 171 PECs were calculated for 20 metabolites in 6 agricultural dry-land scenario locations of Northern China with 8 target crops. In 264 of the 336 cases, the PEC in groundwater is ≤ 0.1 µg/L. Carbofuran, imidacloprid, trichlorfon, and oxidative metabolites of aldicarb are the most leached chemicals in groundwater. The most vulnerable crop is cotton, whereas soil treatment is the most vulnerable application type. Urumqi and Weifang are the most vulnerable situations among the 6 scenario locations. Less than 3% of 336 cases show unacceptable risk of insecticide-contaminated groundwater, thereby requiring higher risk assessment and risk mitigation. The unacceptable cases are the leaching of carbofuran for cotton growing in Urumqi and Weifang, and leaching of metabolites of aldicarb in cotton and tobacco scenarios.CONCLUSIONPopular insecticides used in Northern China are generally safe to groundwater.
      PubDate: 2017-03-15T02:50:25.456636-05:
      DOI: 10.1002/ps.4572
       
  • Biochemical evaluation of interactions between synergistic molecules and
           phase I enzymes involved in insecticide resistance in B- and Q-type
           Bemisia tabaci (Hemiptera: Aleyrodidae)
    • Authors: Michela Panini; Francesco Tozzi, Christoph T Zimmer, Chris Bass, Linda Field, Valerio Borzatta, Emanuele Mazzoni, Graham Moores
      Abstract: BACKGROUNDMetabolic resistance is an important consideration in the whitefly Bemisia tabaci, where an esterase-based mechanism has been attributed to pyrethroid resistance and over-expression of the cytochrome P450, CYP6CM1, has been correlated to resistance to imidacloprid and other neonicotinoids.RESULTSIn vitro interactions between putative synergists and CYP6CM1, B and Q-type esterases were investigated, and structure–activity relationship analyses allowed the identification of chemical structures capable of acting as inhibitors of esterase and oxidase activities. Specifically, methylenedioxyphenyl (MDP) moieties with a polyether chain were preferable for optimum inhibition of B-type esterase, whilst corresponding dihydrobenzofuran structures were potent for the Q-esterase variation. Potent inhibition of CYP6CM1 resulted from structures which contained an alkynyl chain with a terminal methyl group.CONCLUSIONSSynergist candidates could be considered for field control of B. tabaci, especially to abrogate neonicotinoid resistance. © 2017 Society of Chemical Industry
      PubDate: 2017-03-14T08:40:46.166386-05:
      DOI: 10.1002/ps.4553
       
  • Host differentiation and variability of Orobanche crenata populations from
           legume species in Morocco as revealed by cross-infestation and molecular
           analysis
    • Authors: Mounia Ennami; Fatima Zahra Briache, Fatima Gaboun, Rabha Abdelwahd, Lamiae Ghaouti, Loubna Belqadi, James Westwood, Rachid Mentag
      Abstract: BACKGROUNDOrobanche crenata represents a major biotic constraint to production of faba bean and lentil in Morocco. While this parasitic plant attacks both of these crops, the extent to which Orobanche biotypes specialise in parasitising specific crops is unknown. To address this question, we studied O. crenata that grew on different hosts and quantified their host specificity to faba bean and lentil. The virulence of O. crenata populations on each host was investigated through field trials, pot and Petri dishes assays. Genetic diversity of the parasite populations was also assessed through molecular analyses.RESULTSThe two legume species showed distinct patterns of specificity. Faba bean was more susceptible to both O. crenata populations, while the specificity for lentil by lentil-grown O. crenata was evident at the final stage of the parasite life cycle as shown by correspondence factorial analyses. Considerable internal variation (81%) within O. crenata populations parasitising both legume species was observed by molecular analyses, but significant divergence (19%; Ø = 0.189; P = 0.010) among the populations was detected.CONCLUSIONThese results indicate that O. crenata can adapt to specific host species, which is important knowledge when developing integrated pest management practices for parasitic weed control. © 2017 Society of Chemical Industry
      PubDate: 2017-03-14T08:11:04.429481-05:
      DOI: 10.1002/ps.4536
       
  • Synthesis and in vivo fungicidal activity of some new quinoline
           derivatives against rice blast
    • Authors: Xing-Hai Liu; Yue-Ming Fang, Feng Xie, Rui-Rui Zhang, Zhong-Hua Shen, Chen-Xia Tan, Jian-Quan Weng, Tian-Ming Xu, Hong-Ying Huang
      Abstract: BACKGROUNDQuinoline derivatives possess excellent fungicidal activity against rice blast, but quinoline derivatives have not been thoroughly explored as fungicides. In the process of designing new fungicides, the 1,1,1,2,3,3,3-heptafluoropropan-2-yl group was introduced in order to find new structure quinoline derivatives.RESULTSSeventeen new quinoline derivatives containing 1,1,1,2,3,3,3-heptafluoropropan-2-yl moiety were designed and synthesised. In vivo fungicidal activities of these compounds were tested against rice blast. Some of the compounds provided effective control at 100 mg L−1, and a few compounds were effective at 10 mg L−1. Furthermore, a density functional theory study established the structure–activity relationships of the synthesised compounds.CONCLUSIONQuinoline derivatives, especially benzyl (2,3,8-trimethyl-6-(perfluoropropan-2-yl)quinolin-4-yl) carbonate, which possess good control effective against rice blast and cucumber powdery mildew, may become new lead compounds for the development of fungicides with further structure modification. © 2017 Society of Chemical Industry
      PubDate: 2017-03-14T04:50:40.79158-05:0
      DOI: 10.1002/ps.4556
       
  • Mass rearing and augmentative biological control evaluation of Rhynocoris
           fuscipes (Hemiptera: Reduviidae) against multiple pests of cotton
    • Authors: Majesh Tomson; Kitherian Sahayaraj, Vivek Kumar, Pasco B Avery, Cindy L McKenzie, Lance S Osborne
      Abstract: BACKGROUNDRhynocoris fuscipes (Fab.) (Hemiptera: Reduviidae) is a generalist predator of cotton pests and is commonly found inhabiting cotton-growing regions in southern India. With the goal of integrating this predator in standard management practices used against cotton pests on a commercial scale, (1) we developed a protocol for adult group rearing of this predator inside micro-environmental cages (MECs), and (2) we evaluated the biocontrol potential of mass-produced predators against cotton pests under potted and field conditions.RESULTSHigher fecundity and adult longevity of R. fuscipes was recorded in the MECs than under natural growing conditions. The reduviid predator preferred stones and fallen leaves as hiding places in the MECs. The predator showed a higher biocontrol potential during the night hours against two pests, Phenacoccus solenopsis Tinsley and Dysdercus cingulatus (Fab.), than during the day under potted conditions. Under field conditions, R. fuscipes significantly reduced the population of Aphis gossypii Glover, P. solenopsis, D. cingulatus and Helicoverpa armigera (Hübner) by 28, 70, 29 and 50%, respectively. No negative impact of R. fuscipes was reported on other natural enemies present in the cotton agroecosystem.CONCLUSIONSignificantly higher crop yield and cost benefit ratio were observed in R. fuscipes-released plots than in the control plots. The results suggest that R. fuscipes can be mass produced efficiently under controlled conditions in MECs, and used in an integrated management program for multiple cotton pests. © 2017 Society of Chemical Industry
      PubDate: 2017-03-14T04:05:27.220537-05:
      DOI: 10.1002/ps.4532
       
  • Double-stranded RNA delivery through soaking mediates silencing of the
           muscle protein 20 and increases mortality to the Asian citrus psyllid,
           Diaphorina citri
    • Authors: Xiudao Yu; Siddarame Gowda, Nabil Killiny
      Abstract: BACKGROUNDAsian citrus psyllid, Diaphorina citri Kuwayama, is the most important economic pest of citrus because it transmits Candidatus Liberibacter asiaticus (CLas), the causal agent of huanglongbing (HLB). Silencing genes by RNA interference (RNAi) is a promising approach for controlling D. citri. RNAi-based insect management strategies depend on the selection of suitable target genes.RESULTSThe muscle protein 20 gene DcMP20 was characterized from D. citri in an effort to impair proper muscle development through RNAi. Phylogenetic analysis showed that DcMP20 was more closely related to MP20 from Drosophila compared with its counterpart from other insect species. Developmental expression analysis revealed that transcription of DcMP20 was development dependent and reached a maximum level in the last instar (fourth–fifth) of the nymphal stage. The extent of RNAi in D. citri was dose dependent, with dsRNA-DcMP20 at 75 ng µL−1 being sufficient to knock down endogenous DcMP20 expression, which resulted in significant mortality and reduced body weight that positively correlated with the silencing of DcMP20. No effect was found when dsRNA-GFP or water was used, indicating the specific effect of dsRNA-DcMP20.CONCLUSIONOur results suggest that dsRNA can be delivered to D. citri through soaking, and DcMP20 is an effective RNAi target to be used in the management of D. citri. © 2017 Society of Chemical Industry
      PubDate: 2017-03-14T03:55:30.418415-05:
      DOI: 10.1002/ps.4549
       
  • Glyphosate sorption/desorption on biochars – interactions of physical
           and chemical processes
    • Authors: Kathleen E Hall; Kurt A Spokas, Beatriz Gamiz, Lucia Cox, Sharon K Papiernik, William C Koskinen
      Abstract: BACKGROUNDBiochar, a carbon-rich product of biomass pyrolysis, could limit glyphosate transport in soil and remediate contaminated water. The present study investigates the sorption/desorption behavior of glyphosate on biochars prepared from different hardwoods at temperatures ranging from 350 to 900 °C to elucidate fundamental mechanisms.RESULTSGlyphosate (1 mg L−1) sorption on biochars increased with pyrolysis temperature and was highest on 900 °C biochars; however, total sorption was low on a mass basis (
      PubDate: 2017-03-10T10:46:12.349282-05:
      DOI: 10.1002/ps.4530
       
  • Imidacloprid is degraded by CYP353D1v2, a cytochrome P450 over-expressed
           in resistant strain of Laodelphax striatellus
    • Authors: Mohammed Esmail Abdalla Elzaki; Mohammad Asaduzzaman Miah, Min Wu, Haomiao Zhang, Jian Pu, Ling Jiang, Zhaojun Han
      Abstract: BACKGROUNDCytochrome P450s are associated with metabolizing of a wide range of compounds including insecticides. CYP353D1v2 has been found over-expressed in the imidacloprid-resistant strain of Laodelphax striatellus. Thus, this study was conducted to express CYP353D1v2 in Sf9 cell as a recombinant protein, to assess its ability in metabolizing imidacloprid.RESULTSWestern blot and carbon monoxide difference spectra analysis indicated that the intact CYP353D1v2 protein has been successfully expressed in insect cell Sf9. Catalytic activity tests with four traditional P450 activity probing substrates found that the expressed CYP353D1v2 preferentially metabolized p-nitroanisole, ethoxycoumarin and ethoxyresorufin with special activity 32.70, 0.317 and 1.22 pmol/min/pmol protein, respectively, but no activity to L-H EGE. The enzyme activity for degrading imidacloprid was tested by measuring substrate depletion and formation of the metabolite. Kinetic parameters for imidacloprid were tested as Km 5.99 ± 0.95μM and Kcat 0.03 ± 0.0004 per min. The chromatogram analysis showed clearly NADPH-dependent depletion of imidacloprid and formation of an unknown metabolite. The mass spectrum of UPLC-MS demonstrated that the metabolite was an oxidative product of imidacloprid, 5-hydroxy-imidacloprid.CONCLUSIONThese results suggested that CYP353D1v2 in L. striatellus is capable of degrading imidacloprid and the enzyme activity could be well evaluated only by some traditional probing substrates.
      PubDate: 2017-03-10T02:30:24.611269-05:
      DOI: 10.1002/ps.4570
       
  • Our top 10 herbicide-resistant weed management practices
    • Authors: Hugh J Beckie; K Neil Harker
      Abstract: Although proactive or reactive herbicide-resistant weed management (HRWM) practices have been recommended to growers in different agroecoregions globally, there is a need to identify and prioritise those having the most impact in mitigating or managing herbicide selection pressure in the northern Great Plains of North America. Our perspective on this issue is based on collaborative research, extension activities and dialogue with growers or farming experience (cereal, oilseed and pulse crop production) during the past 30 years. We list our top 10 HRWM practices, concluding with the number 1 practice which is the foundation of the other nine practices: crop diversity. Although our top 10 HRWM practices have broad applicability across agroecoregions, their ranking may vary widely. © 2017 Society of Chemical Industry
      PubDate: 2017-03-09T05:05:29.12347-05:0
      DOI: 10.1002/ps.4543
       
  • Degradation of dimethyl disulphide in soil with or without biochar
           amendment
    • Authors: Dawei Han; Dongdong Yan, Aocheng Cao, Wensheng Fang, Pengfei Liu, Yuan Li, Canbin Ouyang, Qiuxia Wang
      Abstract: BACKGROUNDDimethyl disulphide (DMDS) is a new and effective alternative to methyl bromide for soil fumigation. The effect of biochar on the fate of DMDS in soil is not fully understood. The objective of this study was to determine the degradation kinetics of DMDS in different soils and evaluate the effect of biochar amendment on DMDS degradation using incubation experiments.RESULTSThe degradation half-life of DMDS was between 1.05 and 6.66 days under non-sterile conditions, and 12.63 to 22.67 days under sterile conditions in five types of soil. Seven out of the eight tested biochar amendments (BC-2 to BC-8) delayed the degradation of DMDS in soil, increasing the half-life of DMDS in Fangshan soil from 1.05 to 1.16–5.87 days following amendment with 1% (w/w) biochar. The degradation rate of DMDS in Fangshan soil accelerated as the amendment rate of BC-1 increased, and decreased as the amendment rate of BC-7 increased.CONCLUSIONBiodegradation is an important degradation route for DMDS in soil, and DMDS degraded faster in alkaline soil. The effects of biochar amendments on DMDS degradation in soil are determined by complex multiple factors (such as surface area, pH and physicochemical composition), rather than by any single property of biochar. © 2017 Society of Chemical Industry
      PubDate: 2017-03-09T04:05:35.393327-05:
      DOI: 10.1002/ps.4545
       
  • Glyphosate resistance in Ambrosia trifida: II. Rapid response physiology
           and non-target site resistance
    • Authors: Marcelo L. Moretti; Christopher R. Van Horn, Renae Robertson, Kabelo Segobye, Stephen C. Weller, Bryan G Young, William G. Johnson, R. Douglas Sammons, Dafu Wang, Xia Ge, André d'Avignon, Todd A. Gaines, Philip Westra, Amanda C. Green, Taylor Jeffery, Mackenzie A. Lespérance, François J. Tardif, Peter H. Sikkema, J. Christopher Hall, Michael D. McLean, Mark B. Lawton, Burkhard Schulz
      Abstract: BACKGROUNDThe glyphosate-resistant rapid response (GR RR) resistance mechanism in Ambrosia trifida is not due to target site resistance (TSR) mechanisms. This study explores the physiology of the rapid response and the possibility of reduced translocation and vacuolar sequestration as non-target-site resistance (NTSR) mechanisms.RESULTSGR RR leaf discs accumulated hydrogen peroxide within minutes of glyphosate exposure, but only in mature leaf tissue. The rapid response required energy either as light or exogenous sucrose. The combination of phenylalanine and tyrosine inhibited the rapid response in a dose dependent manner. Reduced glyphosate translocation was observed in GR RR, but only when associated with tissue death caused by the rapid response. NMR studies indicated that glyphosate enters the cytoplasm and reaches chloroplasts, and it is not moved into the vacuole of GR RR, GR non-rapid response, or glyphosate-susceptible A. trifida.CONCLUSIONThe GR RR mechanism of resistance is not associated with vacuole sequestration of glyphosate, and the observed reduced translocation is likely a consequence of rapid tissue death. Rapid cell death was inhibited by exogenous application of aromatic amino acids phenylalanine and tyrosine. The mechanism by which these amino acids inhibit rapid cell death in the GR RR phenotype remains unknown, and it could involve glyphosate phytotoxicity or other agents generating reactive oxygen species. Implications of these findings are discussed. The GR RR mechanism is distinct from the currently described glyphosate TSR or NTSR mechanisms in other species.
      PubDate: 2017-03-08T22:45:27.372894-05:
      DOI: 10.1002/ps.4569
       
  • Analysis of oilseed rape stem weevils chemical control using damage rating
           scale
    • Authors: Željko Milovac; Miroslav Zorić, Filip Franeta, Sreten Terzić, Olivera Petrović Obradović, Ana Marjanović Jeromela
      Abstract: BACKGROUNDRape stem weevil (Ceutorhynchus napi Gyll.) and cabbage stem weevil (C. pallidactylus Marsh.) can cause significant yield losses to oilseed rape (Brassica napus L.), and chemical control is often needed to protect crops from these pests. The efficacy of six insecticides, chlorpyriphos + cypermethrin, bifenthrin, alpha-cypermethrin, pirimiphos-methyl, thiacloprid and tau-fluvalinate, was tested in a four year field trial. Besides the standard efficacy analysis expressed through the number of larvae per stem, a damage rating scale was introduced and modelled using a regression model for ordinal categorical data.RESULTSCompared with the control, expressed through damage rating and larval number, treatments with chlorpyriphos + cypermethrin and bifenthrin, showed higher efficacy in the control of stem weevils compared to alpha-cypermethrin and pirimiphos-methyl. The lowest efficacy was observed in treatments with tau-fluvalinate and thiacloprid.CONCLUSIONThis study showed that a combined efficacy evaluation expressed through both damage rating scale and the count of larvae, supported by an ordinal regression model for data analysis, is indispensable for obtaining accurate results.
      PubDate: 2017-03-08T22:30:27.550171-05:
      DOI: 10.1002/ps.4568
       
  • Potential exposure to clothianidin and risk assessment of manual users of
           treated soil
    • Authors: JingXia Ren; ChuanJiang Tao, LiYing Zhang, Jun Ning, XiangDong Mei, DongMei She
      Abstract: BACKGROUNDTreated soil is the second most prevalent application technique for all registered pesticides in China. Some developing countries also adopt this method. However, the safety of this scenario has not been reported in the literature. Experiments were therefore conducted to assess exposure using standard whole-body dosimetry and air sampling methodologies.RESULTSDermal deposition was the main route of exposure in this scenario. The total dermal unit exposure (UE) of operators to clothianidin-treated soil was 51.7 mg kg−1 AI handled (SD = 20.59, n = 16), and hands accounted for 36%. Inhalation UE was 0.04 mg kg−1 AI handled (SD = 0.02, n = 4), negligible compared with dermal exposure. Using an NOAEL (no observed adverse effect level) of 10 mg kg−1 day−1, the margin of exposure was 773, i.e. greater than 100.CONCLUSIONFor the first time, the scenario of treated soil exposure was assessed and was found to pose less risk than conventional pesticide application. These results can be used as a reference in pesticide management. © 2017 Society of Chemical Industry
      PubDate: 2017-03-07T03:15:31.601558-05:
      DOI: 10.1002/ps.4535
       
  • Glyphosate resistance in Ambrosia trifida: I. Novel rapid cell death
           response to glyphosate
    • Authors: Christopher R. Van Horn; Marcelo L. Moretti, Renae R. Robertson, Kabelo Segobye, Stephen C. Weller, Bryan G. Young, William G. Johnson, Burkhard Schulz, Amanda C. Green, Taylor Jeffery, Mackenzie A. Lespérance, François J. Tardif, Peter H. Sikkema, J. Christopher Hall, Michael D. McLean, Mark B. Lawton, R. Douglas Sammons, Dafu Wang, Philip Westra, Todd A. Gaines
      Abstract: BACKGROUNDGlyphosate-resistant (GR) Ambrosia trifida is now present in the Midwestern US and southwestern, Ontario, Canada. Two distinct GR phenotypes are known, including a rapid response (GR RR) phenotype that exhibits cell death within hours after treatment, and a non-rapid response (GR NRR) phenotype. The mechanisms of resistance in both GR RR and GR NRR remain unknown. Here we present a description of the RR phenotype and investigation of target-site mechanisms on multiple A. trifida accessions.RESULTSGlyphosate resistance was confirmed in several accessions and whole plant levels of resistance ranged from 2.3- to 7.5-fold compared to glyphosate-susceptible (GS) accessions. Both GR phenotypes displayed similar levels of resistance despite having dramatically different phenotypic responses to glyphosate. Glyphosate resistance was not associated with mutations in EPSPS sequence, increased EPSPS copy number, EPSPS quantity, or EPSPS activity.CONCLUSIONThese encompassing results suggest resistance to glyphosate in these GR RR A. trifida accessions is not conferred by a target-site resistance mechanism.
      PubDate: 2017-03-07T00:45:38.073622-05:
      DOI: 10.1002/ps.4567
       
  • Enhanced Atrazine Degradation is Widespread Across the United States
    • Authors: Thomas C. Mueller; Ethan T. Parker, Larry Steckel, Sharon A. Clay, Micheal D.K. Owen, William S. Curran, Randall Currie, Robert Scott, Christy Sprague, Daniel O. Stephenson, Donnie K. Miller, Eric P. Prostko, W. James Grichar, James Martin, L. Jason Kruz, Kevin Bradley, Mark L. Bernards, Peter Dotray, Stevan Knezevic, Vince Davis, Robert Klein
      Abstract: BACKGROUNDAtrazine (ATZ) has been a key herbicide for annual weed control in corn, with both a soil and postemergence vegetation application period. Although enhanced ATZ degradation in soil with a history of ATZ use has been reported, the extent and rate of degradation in the U.S. Corn Belt is uncertain. We show that enhanced ATZ degradation exists across much of the country.RESULTSSoils from 15 of 16 surveyed states had enhanced ATZ degradation. The average ATZ half-life was only 2.3 days in ATZ history soils compared with an average 14.5 days in soils with no previous ATZ use, meaning ATZ degrades an average of 6 times faster in soils with previous ATZ use.CONCLUSIONWhen ATZ is used for several years, enhanced degradation will undoubtedly change the way ATZ is used in agronomic crops and also its ultimate environmental fate.
      PubDate: 2017-03-07T00:00:28.730015-05:
      DOI: 10.1002/ps.4566
       
  • Larvicidal activity of synthetic tropane alkaloids against Ascia monuste
           orseis (Lepidoptera: Pieridae)
    • Authors: Simone Z Mairink; Luiz CA Barbosa, Eduardo VV Varejão, Elizeu S Farias, Márcio LM Santos, Marcelo C Picanço
      Abstract: BACKGROUNDTropane alkaloids are well known to play a role in plant defense. By blocking acetylcholine receptors, they exert insecticidal and deterrent effects against herbivore insects. Carbamates are an important class of chemical insecticides that also inhibit acetyl cholinesterase. The objective of this work was to synthesize a series of tropane alkaloids bearing a carbamate group, and to evaluate their effects against the pest Ascia monuste. The effects of the most active compounds were evaluated on the A. monuste predator Solenopsis saevissima and on the pollinator Tetragonisca angustula.RESULTSThe synthesis of carbamate-tropane alkaloids was accomplished in four to five steps from commercially available ketones. Results from bioassays showed that compounds 6a, 10a, and 14a presented higher activities against second-instar larvae of A. monuste, with LD50 of 1.01, 3.76, and 1.92 µg of substance per mg of insect, and TL50 of 7.0, 15.0 and 5.0 hours, respectively. These compounds were also tested for their selectivity in favor of Solenopsis saevissima and Tetragonisca angustula. Compound 6a, which showed the highest activity against A. monuste, also showed lower toxicity against Solenopsis saevissima.CONCLUSIONTropane alkaloids derivatives bearing a carbamate group show potential for the development of novel insecticides against A. monuste.
      PubDate: 2017-03-06T23:50:22.680823-05:
      DOI: 10.1002/ps.4565
       
  • Latest generation of halogen-containing pesticides
    • Authors: Peter Jeschke
      Abstract: Agriculture is confronted with enormous challenges, from production of enough high-quality food to water use, environmental impacts and issues combined with a continually growing world population. Modern agricultural chemistry has to support farmers by providing innovative agrichemicals, used in applied agriculture. In this context, the introduction of halogen atoms into an active ingredient is still an important tool to modulate the properties of new crop protection compounds. Since 2010, around 96% of the launched products (herbicides, fungicides, insecticides/acaricides and nematicides) contain halogen atoms. The launched nematicides contain the largest number of halogen atoms, followed by insecticides/acaricides, herbicides and fungicides. In this context, fungicides and herbicides contain in most cases fluorine atoms, whereas nematicides and insecticides contain in most cases ‘mixed’ halogen atoms, for example chlorine and fluorine. This review gives an overview of the latest generation of halogen-containing pesticides launched over the past 6 years and describes current halogen-containing development candidates. © 2017 Society of Chemical Industry
      PubDate: 2017-03-06T03:55:28.103677-05:
      DOI: 10.1002/ps.4540
       
  • Concentration-dependent effects of acute and chronic neonicotinoid
           exposure on the behaviour and development of the nematode Caenorhabditis
           elegans
    • Authors: Monika M Kudelska; Lindy Holden-Dye, Vincent O'Connor, Declan A Doyle
      Abstract: BACKGROUNDNeonicotinoid insecticides are under review due to emerging toxicity to non-target species. Interest has focused on biological pollinators whilst their effects on other organisms that are key contributors to the ecosystem remain largely unknown. To advance this we have tested the effects of representatives of three major classes of neonicotinoids, thiacloprid, clothianidin and nitenpyram on the free-living nematode Caenorhabditis elegans (C. elegans), as a representative of the Nematoda, an ecologically important phylum contributing to biomass.RESULTSConcentrations that are several-fold higher than those with effects against target species had limited impact on locomotor function. However, increased potency was observed in a mutant with a hyper-permeable cuticle which shows that drug access limits the effects of the neonicotinoids in C. elegans. Thiacloprid was most potent (EC50 714 μM). In addition, it selectively delayed larval development in wild-type worms at 1 mM.CONCLUSIONSC. elegans is less susceptible to neonicotinoids than target species of pest insect. We discuss an approach in which this defined low sensitivity may be exploited by heterologous expression of insect nicotinic acetylcholine receptors from both pest and beneficial insects, in transgenic C. elegans with increased cuticle permeability to provide a whole organism assay for species-dependent neonicotinoid effects.
      PubDate: 2017-03-06T02:05:27.843485-05:
      DOI: 10.1002/ps.4564
       
  • Hormetic effects of glyphosate on plants
    • Authors: Ivana PFS Brito; Leandro Tropaldi, Caio A Carbonari, Edivaldo D Velini
      Abstract: As all herbicides act on pathways or processes crucial to plants, in an inhibitory or stimulatory way, low rates of any herbicide might be used to modulate plant growth, development, or plant composition. Glyphosate is the most used herbicide in the world, and very low rates of this herbicide can stimulate plant growth, an effect called hormesis. Several studies have shown that glyphosate applications at low rates can increase plant growth, induce shikimic acid accumulation, increase photosynthesis and stomatal opening, increase seed production, and shorten the plant life cycle. Low rates of glyphosate applied to leaves have been reported to cause one or more of these effects in an expanding group of species. Under field conditions, pesticide rates are not uniform, causing some target organisms to receive rates that are low enough to cause hormesis. Until the present, low rates of glyphosate have not been recommended as a growth stimulant for crops, because the hormetic dose can vary considerably, depending on many factors. The objective of the present review is to summarize and analyze existing information about the hormetic effects of glyphosate on plants, thus contributing to understanding how glyphosate hormesis takes place and evaluating the potential use of glyphosate to stimulate plant growth. © 2017 Society of Chemical Industry
      PubDate: 2017-03-03T10:20:24.308963-05:
      DOI: 10.1002/ps.4523
       
  • Evolution of imidacloprid resistance in Myzus persicae in Greece and
           susceptibility data for spirotetramat
    • Authors: Costas Ch Voudouris; Martin S Williamson, Panagiotis J Skouras, Amalia N Kati, Anastasia J Sahinoglou, John T Margaritopoulos
      Abstract: BACKGROUNDMyzus persicae s.l. is a major crop pest globally and has evolved resistance to a range of insecticide classes making it increasingly difficult to control in some areas. Here we compare bioassay monitoring data for two important compounds, imidacloprid and spirotetramat, on field samples/clones collected in Greece.RESULTSA total of 122 aphid samples/clones from central and northern Greece were examined in dose–response bioassays with imidacloprid. There was an overall increase in the level of resistance (resistance factor = 15–40) within tobacco-collected samples from 78.7% in 2007 to 86.7% in 2015. The corresponding frequencies for peach samples were 13.3% and 6.7%. These results were confounded however by the first identification of the R81T target mutation in Greece during 2015 (4.3% as heterozygotes in peach) and 2016 (21.3% as heterozygotes in peach). No resistance to spirotetramat was found at the 60 clones collected in 2015.CONCLUSIONResistance to imidacloprid is continuing to increase within Greek M. persicae s.l. populations and the situation is likely to deteriorate further with the recent identification of the R81T resistance mutation. Resistance to spirotetramat has not been found and is therefore a good alternative to neonicotinoids for resistance management. © 2017 Society of Chemical Industry
      PubDate: 2017-03-03T04:10:35.188736-05:
      DOI: 10.1002/ps.4539
       
  • Discovery and quantitative structure-activity relationship study of
           lepidopteran HMG-CoA reductase inhibitors as selective insecticides
    • Authors: Yang-yang Zang; Yuan-mei Li, Yue Yin, Shan-shan Chen, Zhen-peng Kai
      Abstract: BACKGROUNDIn the previous study, we have demonstrated that insect 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) can be a potential selective insecticide target. Three series of inhibitors were designed based on the difference of HMGR structures from Homo sapiens and Manduca sexta with the aim for discovering potent selective insecticide candidate.RESULTSBioassay in vitro showed that gem-difluoromethylenated statin analogs have potent effects on JH biosynthesis of M.sexta and high selectivity between H.sapiens and M.sexta. All series II compounds (1,3,5-Trisubstituted [4-tert-Butyl 2-(5,5-difluoro-2,2-dimethyl-6-vinyl-4-yl) acetate] pyrazoles) have some effect on JH biosynthesis, whereas most of them are inactive on human HMGR. Particularly, the IC50 value of compound II-12 (IC50 value: 37.8 nM) is lower than lovastatin (IC50 value: 99.5 nM) and similar to rosuvastatin (IC50 value: 24.2 nM). Bioassay in vivo showed that I-1, I-2, I-3 and II-12 are potential selective insecticides, especially for lepidopteran pest control. A predictable and statistically meaningful CoMFA model of 23 inhibitors (20 as training sets and 3 as test sets) was obtained with the value of q2 and r2 of 0.66 and 0.996 respectively. The final model suggested that a potent insect HMGR inhibitor should contain suitable small and non-electronegative groups at the ring part, electronegative groups at the side chain.CONCLUSIONFour analogs were discovered as the potent selective lepidopteran HMGR inhibitors, which can specifically used for lepidopteran pest control. The CoMFA model will be useful for the design of new selective insect HMGR inhibitors that are structurally related to the training set compounds.
      PubDate: 2017-03-01T03:35:26.995043-05:
      DOI: 10.1002/ps.4561
       
  • Sea lice infestation levels decrease with deeper ‘snorkel’ barriers in
           Atlantic salmon sea-cages
    • Authors: Oppedal Frode, Samsing Francisca, Dempster Tim, Wright Daniel W; Bui Samantha, Stien Lars H
      Abstract: BACKGROUNDSalmon lice (Lepeophtheirus salmonis) are the most important parasite of farmed salmon. Infective larvae position themselves in the upper part of the water column to increase encounter probabilities with potential hosts. Previous studies have shown that a ‘snorkel’ sea-cage technology protects salmon from infection in surface waters. We tested whether deep snorkels would more effectively reduce lice infestation than shallow snorkels and still uphold adequate conditions for the fish. Five sea-cages (12 m × 12 m) each holding approximately 3000 Atlantic salmon (Salmo salar) (53 ± 10 g) were fitted with snorkels that gave protection from infection for 0, 4, 8, 12 or 16 m. We tested if reductions in the settlement of new salmon lice copepodids were consistent among 4 separate infection periods.RESULTSLice infestation decreased exponentially with depth in all time periods. Infection levels in shallow snorkels (0 and 4 m) were consistently four to ten times higher than those in deep snorkels (12 and 16 m). Key welfare and production performance indices were similar across all snorkel depths.CONCLUSIONDeeper snorkels dramatically and consistently reduced infection levels of salmon lice compared to shallow snorkels without consequences for fish welfare and production performance. Therefore, reducing salmon sea lice encounters using a depth-based barrier is a powerful management tool for salmon farming.
      PubDate: 2017-03-01T02:50:29.143045-05:
      DOI: 10.1002/ps.4560
       
  • Design, Synthesis and Insecticidal Activity of Novel Hydrocarbylidene
           Nitrohydrazinecarboximidamides
    • Authors: Yong Xu; Dong-yan Yang, Xiang-gao Zou, Chang-hui Rui, Zi-yuan Zhou, Yong-qiang Ma, Zhao-hai Qin
      Abstract: BACKGROUNDNeonicotinoids, as one of the most important pesticides in recent decades, have played pivotal roles in controlling of agricultural pests. However, the toxicity to some environmental beneficial insects has been alerting people. The development of novel insecticides safer to these insects is increasingly urgent.RESULTSA novel series of hydrocarbylidene nitrohydrazinecarboximidamides were designed and synthesized starting from S-methylisothiourea sulfate. Preliminary bioassays showed that the target molecules exhibited good activities against Lipaphis erysimi (turnip aphid) and Myzus perslcae. As shown by the initial insecticidal activity data, most of the target compounds had moderate to excellent activities at the concentration of 600 mg/L against L. erysimi and the lethal rate of most compounds exceeded 90%. They were also highly effective against M. perslcae. Some of them have shown excellent insecticidal activities, for example, the LC50 values of compounds Ie-02 ~ Ie-07 were found to be 3.8, 3.0, 2.5, 3.1, 4.1 and 4.0 mg/L, respectively.CONCLUSIONThe structure-activity relationship (SAR) analysis indicated that a suitable flexible alkyl chain at imine point and a Cl-substituted pyridine ring are the most crucial factors affecting the activity.
      PubDate: 2017-03-01T02:36:07.926525-05:
      DOI: 10.1002/ps.4559
       
  • Cover Image, Volume 73, Issue 4
    • Authors: Thomas C Sparks; Beth A Lorsbach
      Abstract: The cover image of a scentless plant bug feeding on a cotton square is based on the Perspective Perspectives on the agrochemical industry and agrochemical discovery, by Thomas C. Sparks and Beth A Lorsbach,
      DOI : 10.1002/ps.4457. Photo Credit: William Fisher – Hillsborough, North Carolina.The cover image of a scentless plant bug feeding on a cotton square is based on the Perspective Perspectives on the agrochemical industry and agrochemical discovery, by Thomas C. Sparks and Beth A Lorsbach,
      DOI : 10.1002/ps.4457. Photo Credit: William Fisher – Hillsborough, North Carolina.
      PubDate: 2017-03-01T02:18:06.975819-05:
       
  • Integrated pest management in western flower thrips: past, present and
           future
    • Authors: Sanae Mouden; Kryss Facun Sarmiento, Peter GL Klinkhamer, Kirsten A Leiss
      Abstract: Western flower thrips (WFT) is one of the most economically important pest insects of many crops worldwide. Recent EU legislation has caused a dramatic shift in pest management strategies, pushing for tactics that are less reliable on chemicals. The development of alternative strategies is therefore an issue of increasing urgency. This paper reviews the main control tactics in integrated pest management (IPM) of WFT, with the focus on biological control and host plant resistance as areas of major progress. Knowledge gaps are identified and innovative approaches emphasised, highlighting the advances in ‘omics’ technologies. Successful programmes are most likely generated when preventive and therapeutic strategies with mutually beneficial, cost-effective and environmentally sound foundations are incorporated. © 2017 The
      Authors . Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
      PubDate: 2017-02-28T08:06:05.749205-05:
      DOI: 10.1002/ps.4531
       
  • Superparasitism, immune response and optimum progeny yield in the
           gregarious parasitoid Palmistichus elaeisis
    • Authors: Kleber de S Pereira; Nelsa Maria P Guedes, José E Serrão, José C Zanuncio, Raul Narciso C Guedes
      Abstract: BACKGROUNDThe subsequent deposition of an egg clutch by a female parasitoid into a host already parasitised either by itself or a conspecific (i.e. superparasitism) is a counterintuitive adaptive strategy, particularly considering the female parasitoid's ability to recognise the parasitised hosts. Such a scenario suggests that the adaptive value of superparasitism depends on the number of clutches laid in the same host, with consequences for parasitoid progeny yield. Here, we tested whether such is the case for the gregarious parasitoid Palmistichus elaeisis and explored its underlying basis.RESULTSAllowing female parasitoids to lay multiple egg clutches in a single melonworm host pupa, parasitoid progeny and fitness exhibited a peak or optimum at three egg clutches laid per host pupa. In addition, haemocyte count, encapsulation and melanisation decreased with the number of egg clutches laid per host pupa.DISCUSSIONAn optimum number of three clutches laid per host pupa was detected for P. elaeisis. As immune response via haemocyte production, encapsulation and melanisation decreased with the number of clutches laid per host, the higher parasitoid yield and fitness observed is the likely consequence of a compromised immune response coupled with an accommodative (i.e. scramble) larval competitive strategy allowing enough resources for optimum balance of parasitoid number and quality produced. © 2017 Society of Chemical Industry
      PubDate: 2017-02-27T05:41:15.282964-05:
      DOI: 10.1002/ps.4534
       
  • Raspberry ketone supplement promotes early sexual maturation in male
           Queensland fruit fly, Bactrocera tryoni (Diptera: Tephritidae)
    • Authors: Humayra Akter; Vivian Mendez, Renata Morelli, Jeanneth Pérez, Phillip W Taylor
      Abstract: BACKGROUNDRaspberry ketone (RK) is highly attractive to sexually mature, but not immature, males of many Bactrocera species, including Queensland fruit fly (‘Qfly’, Bactrocera tryoni), and acts as a metabolic enhancer in a wide diversity of animals. We considered the possibility that, as a metabolic enhancer, RK in adult diet might accelerate sexual maturation of male Qflies.RESULTSRecently emerged adult Qfly males (0–24 h old) were exposed to RK-treated food for 48 h and were then provided only sugar and water. Four doses of RK (1.25, 2.5, 3.75 and 5%) along with control (0%) were tested with two types of food: sugar alone and sugar mixed with yeast hydrolysate (3:1). For flies tested when 4–10 days old all RK doses increased mating probability of flies fed sugar mixed with yeast hydrolysate but did not show any effect on mating probability of flies fed only sugar. No effects of RK were found for flies tested when 10–30 days old for either diet group. There was no evidence that RK affected longevity at any of the doses tested.CONCLUSIONFeeding of RK together with yeast hydrolysate to immature Qfly increases mating propensity at young ages and accordingly shows significant potential as a pre-release supplement that might increase the proportion of released flies that attain sexual maturation in Sterile Insect Technique programmes. © 2017 Society of Chemical Industry
      PubDate: 2017-02-25T13:55:29.689093-05:
      DOI: 10.1002/ps.4538
       
  • Novel nanoscale pheromone dispenser for more accurate evaluation of
           Grapholita molesta (Lepidoptera: Tortricidae) attract-and-kill strategies
           in laboratory
    • Authors: Bruna Czarnobai De Jorge; Ricardo Bisotto-de-Oliveira, Cláudio Nunes Pereira, Josué Sant'Ana
      Abstract: BACKGROUNDNanotechnology has recentlyallowed the production of formulations for controlled release of active ingredients. In the present study, the electrospinning technique was used for nanoscale dispensers production to attract-and-kill strategies. Non-woven nanofibers containing insecticide (cypermethrin) and (E)-8, (Z)-8-dodecenyl acetate and (Z)-8-dodecanol (0.87 mg.L−1), the main components of Grapholita molesta (Lepidoptera:Tortricidae) (Busck) pheromone were evaluated in laboratory experiments. Male electroantenographic (EAG) responses and mortality (tarsal-contact and attract-and-kill behavioral cages) bioassays were performed for nanofibers (with and without insecticide) exposed for different periods (21, 42, 63 e 84 days) in controlled and non-exposed conditions.RESULTSThere were no significant differences in G. molesta male EAG responses based on the time of exposure within treatments. Nanofibers with only pheromone and pheromone plus insecticide elicited equal EAG responses. Mortality in tarsal-contact bioassays was greater than 87%, after 84-day exposure. Regarding attract-and-kill bioassays, mortality ranged from 28.4 to 56.6%, though no difference was observed on insect mortalities over time (24, 48 and 72 h).CONCLUSIONIncorporation of cypermethrin in nanofibers did not interfere in G. molesta attractiveness. Both aspects of the strategy, the attractant and killing effects, were recorded using innovative nanofibers, and long-term effects suggest a controlled release of pheromone and insecticide.
      PubDate: 2017-02-24T02:50:29.445466-05:
      DOI: 10.1002/ps.4558
       
  • Comparing different techniques to assess the risk for dust drift from
           pesticide-coated seeds
    • Authors: Dieter Foque; Bert Beck, Wouter Devarrewaere, Pieter Verboven, David Nuyttens
      Abstract: BACKGROUNDAlthough considered as a save pesticide application method, treated seeds can pose environmental risks when abraded pesticide-laden seed particles are expelled during sowing. This dust drift risk is clearly linked with the seed coating quality. Seed coating quality is traditionally assessed with Heubach dustmeters and guidelines are established in terms of ‘Heubach value’. This technique may, however, not take all drift sensitive particles in to account. In this study, results of the Heubach test are compared to two alternative setups: mechanical sieving and individual sowing element.RESULTSThe abrasion potential assessed with the Heubach dustmeter was much lower than the total dust fraction generated by mechanical sieving and the individual sowing element. The amount of dust produced and its particle size distribution of the both other techniques were comparable.CONCLUSIONIt looks like the Heubach dust meter underestimates the risk of dust drift. Using one of the alternative methods might be a more appropriate way to assess the abrasion potential of seeds. Due to the low investment cost required, mechanical sieving seems a good approach for non-specialized labs. The individual sowing element setup is the most realistic simulation of the in-field dust drift generation but requires a higher initial investment. Therefore, this setup is most suitable for specialized labs and is recommended for further research in this area.
      PubDate: 2017-02-24T02:50:27.13633-05:0
      DOI: 10.1002/ps.4557
       
  • Evaluation of the efficacy of insecticidal coatings based on teflutrin and
           chlorpyrifos against Rhynchophorus ferrugineus
    • Authors: Massimo Pugliese; Andrea Alberto Rettori, Roberto Martinis, Khalid Al-Rohily, Suresh Velate, Mohamed Ashraf Moideen, Ali Al-Maashi
      Abstract: BACKGROUNDThe date palm (Phoenix dactylifera L.), an important economic resource for many nations worldwide, has recently been threatened by the presence of different insect pests, like the red palm weevil (RPW) Rhynchophorus ferrugineus.RESULTSTwo products, a glue (polyvinyl acetate) and an oil (raw linseed oil) were used as coatings and applied together with a repellent and two insecticides (teflutrin and chlorpyrifos) at different dosages on two species of palm (P. dactylifera and P. canariensis). Phytotoxic effects of the treatments were evaluated in a greenhouse on 260 potted palms (130 P. dactylifera and 130 P. canariensis) and no negative effects were observed. Afterwards, a trial lasting 400 days was carried out in a nursery located in Sicily (south Italy), treating 572 potted palm trees (286 P. dactylifera and 286 P. canariensis) with an average diameter at the base of 18–20 cm. After 400 days, 48% of the untreated palms were infested, while only 3% of date palms and 7% of Canary palms treated with insecticide at lower dosages were infested.CONCLUSIONSThe application of an insecticide-based coating is a good strategy to control and prevent the red palm weevil infestation, in particular on date palms. © 2017 Society of Chemical Industry
      PubDate: 2017-02-22T03:15:24.102036-05:
      DOI: 10.1002/ps.4527
       
  • Delivering Beauveria bassiana with electrostatic powder for the control of
           stored-product beetles
    • Authors: Christos G Athanassiou; Christos I Rumbos, Maria Sakka, Olivier Potin, Clare Storm, Aoife B Dillon
      Abstract: BACKGROUNDThe efficacy of a Beauveria bassiana-based formulation (Bb38) with Entostat, an electrostatically charged powder, was investigated as a surface treatment against Cryptolestes ferrugineus, Oryzaephilus surinamensis and Sitophilus granarius adults. In lab bioassays, the efficacy of Bb38 against the aforementioned species was examined on concrete, plywood, steel and ceramic, whereas its residual efficacy against the same species was assessed on concrete and steel in the presence or absence of illumination. Finally, the efficacy of Bb38 against O. surinamensis and S. granarius adults was assessed in a commercial grain storage facility under realistic field conditions.RESULTSIn the lab trials, O. surinamensis and C. ferrugineus were much more susceptible to Bb38 than S. granarius on all types of surfaces. Moreover, Bb38 was, at least for O. surinamensis and C. ferrugineus, as effective as the chemical standard (deltamethrin) for at least 2 months after the application, regardless of the presence or absence of illumination. Finally, in the field trial Bb38 provided a satisfactory level of control against O. surinamensis.CONCLUSIONBb38 is an effective surface treatment, but its efficacy varies according to the target species, the type of surface and the time post-application. This is the first published report that examines the efficacy of Bb38 as a surface treatment for wider uses in empty warehouses and related storage facilities. © 2017 Society of Chemical Industry
      PubDate: 2017-02-22T03:10:31.071684-05:
      DOI: 10.1002/ps.4522
       
  • The adverse impact of the neonicotinoid seed treatment ban on crop
           protection in oilseed rape in the United Kingdom
    • Authors: Alan M Dewar
      Abstract: This paper describes the consequences of the ban on neonicotinoid seed treatments on pest management in oilseed rape. Since the ban was implemented in December 2013, there have been serious crop losses in 2014, 2015 and 2016 owing to cabbage stem flea beetles, Psylliodes chrysocephala, and aphids, Myzus persicae, which have developed resistance to the alternative pyrethroid sprays that were employed to control them. This has resulted in increased crop losses, decreased yields and a substantial decrease in the area grown, leading to fewer flowering crops available in the spring, especially in the eastern region of the United Kingdom. This is likely to have an adverse effect on bees locally. © 2016 Society of Chemical Industry
      PubDate: 2017-02-22T03:05:51.637601-05:
      DOI: 10.1002/ps.4511
       
  • Identification and detection of indoxacarb resistance mutations in the
           para sodium channel of the tomato leafminer, Tuta absoluta
    • Authors: Emmanouil Roditakis; Konstantinos Mavridis, Maria Riga, Emmanouil Vasakis, Evangelia Morou, Jean Luc Rison, John Vontas
      Abstract: BACKGROUNDIndoxacarb is an important active ingredient extensively used for the control of Tuta absoluta, a major tomato pest, playing a particular role in insecticide resistance management schemes.RESULTSReduced susceptibility to indoxacarb was identified (1794-fold resistance) through toxicological bioassays in a field population from Greece and evolved rapidly to resistance after short laboratory selection. Combined bioassays with synergists and biochemical analysis suggested only a partial involvement of detoxification enzymes in the resistant phenotype. To investigate the role of target-site resistance, segment 6 of domain IV of the sodium channel in T. absoluta was cloned and the sequences compared between susceptible and indoxacarb-resistant T. absoluta insects. The presence of the F1845Y and the V1848I indoxacarb resistance mutations was detected and was strongly associated with the phenotype. These amino acid substitutions correspond to recently characterised indoxacarb resistance mutations in diamondback moth (Plutella xylostella). Robust and accurate PCR-RFLP assays were subsequently developed and successfully validated for detecting both indoxacarb resistance mutations in field T. absoluta populations.CONCLUSIONThe identification of indoxacarb resistance mutations and the development of diagnostic tools will allow early detection of indoxacarb resistance, facilitating implementation of appropriate resistance management strategies, thus delaying the spread of resistance. © 2016 Society of Chemical Industry
      PubDate: 2017-02-20T03:36:15.140924-05:
      DOI: 10.1002/ps.4513
       
  • Characterisation of glufosinate resistance mechanisms in Eleusine indica
    • Authors: Adam Jalaludin; Qin Yu, Peter Zoellner, Roland Beffa, Stephen B Powles
      Abstract: BACKGROUNDAn Eleusine indica population has evolved resistance to glufosinate, a major post-emergence herbicide of global agriculture. This population was analysed for target-site (glutamine synthetase) and non-target-site (glufosinate uptake, translocation and metabolism) resistance mechanisms.RESULTSGlutamine synthetase (GS) activity extracted from susceptible (S) and resistant (R*) plants was equally sensitive to glufosinate inhibition, with IC50 values of 0.85 mm and 0.99 mm, respectively. The extractable GS activity was also similar in S and R* samples. Foliar uptake of [14C]-glufosinate did not differ in S and R* plants, nor did glufosinate net uptake in leaf discs. Translocation of [14C]-glufosinate into untreated shoots and roots was also similar in both populations, with 44% to 47% of the herbicide translocated out from the treated leaf 24 h after treatment. The HPLC and LC-MS analysis of glufosinate metabolism revealed no major metabolites in S or R* leaf tissue.CONCLUSIONSGlufosinate resistance in this resistant population is not due to an insensitive GS, or increased activity, or altered glufosinate uptake and translocation, or enhanced glufosinate metabolism. Thus, target-site resistance is likely excluded and the exact resistance mechanism(s) remain to be determined. © 2017 Society of Chemical Industry
      PubDate: 2017-02-20T03:15:29.519383-05:
      DOI: 10.1002/ps.4528
       
  • Why was resistance to shorter-acting pre-emergence herbicides slower to
           evolve?
    • Authors: Gayle J Somerville; Stephen B Powles, Michael J Walsh, Michael Renton
      Abstract: BACKGROUNDAcross several agricultural systems the evolution of herbicide resistance has occurred more rapidly to post-emergence than pre-emergence herbicides; however, the reasons for this are not clear. We used a new simulation model to investigate whether interactions between differences in order of application and weed cohorts affected could explain this historically observed difference between the herbicide groups.RESULTSA 10 year delay in resistance evolution was predicted for a shorter-acting residual pre-emergence (cf. post-emergence), when all other parameters were identical. Differences in order of application between pre- and post-emergence herbicides had minimal effect on rates of resistance evolution when similar weed cohorts were affected.CONCLUSIONThis modelling suggested that the historically observed lower levels of resistance to pre-emergence herbicides are most likely to be due to the smaller number of weed cohorts affected by many pre-emergence herbicides. The lower number of weed cohorts affected by pre-emergence herbicides necessitated the use of additional, effective control measures, thereby reducing resistance evolution. This study highlights the advantages of applying multiple control measures to each weed cohort. © 2016 Society of Chemical Industry
      PubDate: 2017-02-20T03:10:32.955177-05:
      DOI: 10.1002/ps.4509
       
  • Identification of glyphosate resistance in Salsola tragus in north-eastern
           Oregon
    • Authors: Judit Barroso; Jennifer A Gourlie, Larry K Lutcher, Mingyang Liu, Carol A Mallory-Smith
      Abstract: BACKGROUNDFarmers in the low-rainfall region of eastern Oregon rely on repeated applications of non-selective herbicides, predominately glyphosate, to control Salsola tragus in no-till fallow systems. Reports of poor glyphosate effectiveness have increased in recent years. Reduced efficacy is often attributed to dust, water stress, or generally poor growing conditions during application. Inadequate control also may be the result of the evolution of glyphosate resistance. Therefore, studies were undertaken to determine if glyphosate-resistant S. tragus populations occur in Oregon.RESULTSResults from dose–response studies confirmed glyphosate resistance in three of 10 Oregon Salsola tragus populations. The ratio I50R/I50S from dose–response curves was, on average, 3.1 for the relative dry biomass per plant and 3.2 for the % of surviving plants per pot in these three populations. Plant mortality at recommended glyphosate doses for the resistant populations was less than 30% 3 weeks after treatment.CONCLUSIONSGlyphosate resistance in S. tragus highlights the imperative need to diversify weed control strategies to preserve the longevity and sustainability of herbicides in semi-arid cropping systems of the Pacific Northwest. © 2017 Society of Chemical Industry
      PubDate: 2017-02-16T08:50:26.999768-05:
      DOI: 10.1002/ps.4525
       
  • Basis of ACCase and ALS inhibitor resistance in Hordeum glaucum Steud
    • Authors: Lovreet S Shergill; Jenna Malone, Peter Boutsalis, Christopher Preston, Gurjeet Gill
      Abstract: BACKGROUNDAcetyl coenzyme-A carboxylase (ACCase) and/or acetolactate synthase (ALS) inhibitor resistance has been identified by herbicide resistance screening in eight populations obtained from cropping regions of South Australia. This study aimed to quantify the level of resistance and characterise the molecular basis of resistance to ACCase and ALS inhibitors in these H. glaucum populations.RESULTSH. glaucum populations from the Upper-North region were highly resistant (resistance index RI > 12) to the aryloxyphenoxypropionate (APP) herbicides quizalofop and haloxyfop and less resistant (RI = 2–12) to cyclohexanedione (CHD) herbicide clethodim, and some Mid-North populations had a low level of resistance (RI = 2–6) to the sulfonylurea (SU) herbicide mesosulfuron. Gene sequencing confirmed the presence of Ile-1781-Leu, Ile-2041-Asn and Gly-2096-Ala mutations in the ACCase gene, with no mutation found in the ALS gene. The use of the known metabolic inhibitor malathion in combination with mesosulfuron enhanced the activity of this herbicide. These populations were also susceptible to SU herbicide sulfometuron.CONCLUSIONThis study has documented APP-to-CHD herbicide cross-resistance, the first case of ACCase inhibitor resistance due to Ile-2041-Asn mutation, and characterised the resistance to ALS inhibitors in H. glaucum. Resistance to ACCase inhibitors is due to a target-site mutation. The reversal of SU resistance by malathion and susceptibility to sulfometuron suggests that non-target-site mechanisms confer resistance to ALS inhibitors. © 2016 Society of Chemical Industry
      PubDate: 2017-02-15T03:35:28.603037-05:
      DOI: 10.1002/ps.4501
       
  • Characteristics of dust particles abraded from pesticide treated seeds: 2.
           Density, porosity and chemical content
    • Authors: Dieter Foqué; Wouter Devarrewaere, Pieter Verboven, David Nuyttens
      Abstract: BACKGROUNDApart from particle size, drift of abraded seed particles during sowing is mainly affected by two other physical properties, viz. particle shape and envelope density. The impact of these abraded seed particles on the environment is highly dependable on their active ingredient content. In this study, the envelope density and chemical content of dust abraded from seeds was determined as a function of particle size for six seed species.RESULTSEnvelope density and active ingredient content both change as a function of particle size. Important differences in these physico-chemical properties were observed between the six species. Functions were fitted to the collected data to describe the physico-chemical properties as a function of particle size.CONCLUSIONThe gathered physico-chemical information is essential for the computational fluid dynamics (CFD)-based dust drift prediction models and can be useful for other prediction models as well as for the ongoing risk assessment of active ingredients used for seed treatment on ecosystems and ecosystem-services. In addition, the results can help to better understand the dust drift phenomenon and to develop mitigation strategies. © 2017 Society of Chemical Industry
      PubDate: 2017-02-15T02:50:59.236587-05:
      DOI: 10.1002/ps.4524
       
  • Characteristics of dust particles abraded from pesticide treated seeds: 1.
           Size distribution using different measuring techniques
    • Authors: Dieter Foqué; Ingrid KA Zwertvaegher, Wouter Devarrewaere, Pieter Verboven, David Nuyttens
      Abstract: BACKGROUNDParticle size is one of the most important properties affecting the driftability and behaviour of dust particles abraded from pesticide dressed seeds during sowing. Three particle sizing techniques were used determine the particle size distribution of dust abraded from seeds from six different species.RESULTSImportant differences in dust particle size distribution between species were observed with the finest dust for rapeseed and the coarsest dust for barley. Wet laser diffraction and sonic sieving particle size results correlated well while micro-CT is able to deliver three-dimensional information and additional physical particle properties (shape, porosity).CONCLUSIONAll particle sizing techniques have their (dis)advantages and none of them is able to perfectly describe the real size distribution of non-spherical particles. The particle size information gathered can be used in dust drift prediction models, risk assessment tools and will help to better understand the dust drift phenomenon. © 2017 Society of Chemical Industry
      PubDate: 2017-02-15T02:50:53.664604-05:
      DOI: 10.1002/ps.4526
       
  • The toxicity of flonicamid to cotton leafhopper, Amrasca biguttula
           (Ishida), is by disruption of ingestion: an electropenetrography study
    • Authors: Kaleem Tariq; Mah Noor, Elaine A Backus, Adil Hussain, Asad Ali, Wei Peng, Hongyu Zhang
      Abstract: BACKGROUNDThe cotton leafhopper, Amrasca biguttula, is one of the most destructive pests of cotton in Asia. This species is thought to cause damage by injecting enzymatic saliva into various, presently unknown, cotton tissues and ingesting the resulting macerate. Flonicamid is a novel systemic insecticide used to control the cotton leafhopper; however, its mode of action is unknown.RESULTSThe mechanism of action of flonicamid on cotton leafhopper was investigated using electropenetrography (EPG). EPG recordings revealed six waveforms, i.e. Np (non-probing), A1 (channel cutting), A2, A3, A4, A5 and A6. Waveforms A2 and A3 probably represent active ingestion with (A2) and without (A3) simultaneous watery salivation. The meanings of A4, A5 and A6 are presently unknown, but minor in duration. Flonicamid significantly increased the mean duration of non-probing events and strongly inhibited ingestion by treated insects, which resulted in the slow death of leafhoppers. Inhibition of ingestion was dose dependent, and near-complete suppression was observed when the flonicamid concentration was increased to 10 000 mg L−1.CONCLUSIONSWe propose that starvation caused by inhibition of active ingestion is the mechanism of toxicity for flonicamid. This knowledge could aid in applicability and use of this new insecticide for field management of leafhopper populations. © 2016 Society of Chemical Industry
      PubDate: 2017-02-13T09:20:29.173576-05:
      DOI: 10.1002/ps.4508
       
  • Target-site mutations conferring resistance to glyphosate in feathertop
           Rhodes grass (Chloris virgata) populations in Australia
    • Authors: The D Ngo; Mahima Krishnan, Peter Boutsalis, Gurjeet Gill, Christopher Preston
      Abstract: BACKGROUNDChloris virgata is a warm-season, C4, annual grass weed affecting field crops in northern Australia that has become an emerging weed in southern Australia. Four populations with suspected resistance to glyphosate were collected in South Australia, Queensland and New South Wales, Australia, and compared with one susceptible (S) population to confirm glyphosate resistance and elucidate possible mechanisms of resistance.RESULTSBased on the rate of glyphosate required to kill 50% of treated plants (LD50), glyphosate resistance (GR) was confirmed in four populations of C. virgata (V12, V14.2, V14.16 and V15). GR plants were 2–9.7-fold more resistant and accumulated less shikimate after glyphosate treatment than S plants. GR and S plants did not differ in glyphosate absorption and translocation. Target-site EPSPS mutations corresponding to Pro-106-Leu (V14.2) and Pro-106-Ser (V15, V14.16 and V12) substitutions were found in GR populations. The population with Pro-106-Leu substitution was 2.9–4.9-fold more resistant than the three other populations with Pro-106-Ser substitution.CONCLUSIONThis report confirms glyphosate resistance in C. virgata and shows that target-site EPSPS mutations confer resistance to glyphosate in this species. The evolution of glyphosate resistance in C. virgata highlights the need to identify alternative control tactics. © 2016 Society of Chemical Industry
      PubDate: 2017-02-13T09:05:25.969805-05:
      DOI: 10.1002/ps.4512
       
  • Heterologous Expression of Helicoverpa armigera Cytochrome P450 CYP6B7 in
           Pichia pastoris and Interactions of CYP6B7 with Insecticides
    • Authors: Chunqing Zhao; Genmiao Song, Hongxia Duan, Tao Tang, Chen Wang, Lihong Qiu
      Abstract: BACKGROUNDPrevious studies indicated that constitutive overexpression of cytochrome P450 CYP6B7 was involved in fenvalerate resistance in Helicoverpa armigera. In this study, the CYP6B7 gene from H. armigera (namely HaCYP6B7), was heterologously expressed in Pichia pastoris GS115. A vector pPICZA-HaCYP6B7 was constructed and transformed into P. pastoris GS115, the transformant of pPICZA-HaCYP6B7-GS115 was then cultured and induced by 1% (v/v) methanol and the heterologous expression of HaCYP6B7 protein in P. pastoris was confirmed by SDS-PAGE and western blot.RESULTSMicrosomes containing the expressed HaCYP6B7 showed activities against model substrate p-nitroanisole and 7-ethoxycoumarin, with p-nitroanisole O-demethylation (PNOD) and 7-ethoxycoumarin O-deethylation (ECOD) activities of 15.66 and 4.75-fold of the control, respectively. Moreover, it showed degradation activities against insecticides bifenthrin, fenvalerate and chlorpyrifos, with clearance activities of 6.88, 1.49 and 2.27-fold of the control respectively. The interactions of HaCYP6B7 with insecticides were further confirmed by molecular docking in silico with binding scores of 5.450, 5.295 and 2.197 between putative HaCYP6B7 protein and bifenthrin, fenvalerate and chlorpyrifos, respectively.CONCLUSIONThe results of present study provided more direct and important evidence on the role of HaCYP6B7 conferring pyrethroid resistance in H. armigera.
      PubDate: 2017-02-13T08:05:25.033379-05:
      DOI: 10.1002/ps.4552
       
  • Interaction of transgenic and natural insect resistance mechanisms against
           Spodoptera littoralis in cotton
    • Authors: Steffen Hagenbucher; Michael Eisenring, Michael Meissle, Jörg Romeis
      Abstract: BACKGROUNDInsect-resistant transgenic plants that express insecticidal Cry proteins from Bacillus thuringiensis (Bt) are grown on millions of hectares worldwide. While these proteins are efficient in controlling key lepidopteran pests, not all pests are affected and the development of resistance in target pests is always a concern. These shortcomings could be addressed by exploiting the natural insect resistance of cotton, especially inducible terpenoids such as gossypol.RESULTSTo assess the potential of gossypol in supplementing Cry proteins as a resistance trait, we conducted a range of feeding assays with Spodoptera littoralis using artificial diet with defined amounts of Cry proteins and gossypol. This was supplemented by assays with leaf discs of induced and uninduced non-Bt and Bt cotton (expressing Cry1Ac and Cry2Ab). Additionally, we quantified Cry proteins and cotton terpenoids to describe the interactions in planta. We found that gossypol can increase the efficacy of Cry proteins in artificial diet in an additive way. Induced production of gossypol and other cotton terpenoids, however, did not increase the efficacy of Bt cotton owing to the strong impact of the Bt trait.CONCLUSIONCotton terpenoids may offer the chance to supplement the insect resistance of Bt cotton in cases were the pest is not strongly affected by the Cry proteins. © 2016 Society of Chemical Industry
      PubDate: 2017-02-13T03:40:43.1985-05:00
      DOI: 10.1002/ps.4510
       
  • Inductions of reproduction and population growth in the generalist
           predator Cyrtorhinus lividipennis (Hemiptera: Miridae) exposed to
           sub-lethal concentrations of insecticides
    • Authors: Weiwei Lu; Qiujing Xu, Jun Zhu, Chen Liu, Linquan Ge, Guoqing Yang, Fang Liu
      Abstract: BACKGROUNDThe miridbug, Cyrtorhinus lividipennis, is a significant predacious enemy of rice planthoppers. The effects of sub-lethal concentrations of triazophos, deltamethrin and imidacloprid on fecundity, egg hatchability, expression levels of genes associated with reproduction, and population growth in C. lividipennis were investigated.RESULTSThe fecundities for three pair combinations (♀c × ♂t, ♀t × ♂c and ♀t × ♂t) treated with sub-lethal concentrations of the insecticides triazophos, deltamethrin and imidacloprid (LC10 and LC20) showed a significant increase compared to the untreated pairs (♀c × ♂c). However, sub-lethal concentration treatments did not affect the egg hatchability. The ClVg expression levels of female adults exposed to triazophos, deltamethrin and imidacloprid (LC20) increased by 52.6, 48.9 and 91.2%, respectively. The ClSPATA13 expression level of adult males exposed to triazophos, deltamethrim and imidacloprid (LC20) increased by 80.7, 41.3 and 48.3%, respectively. Furthermore, sub-lethal concentrations of insecticides (LC20) caused increased population numbers in C. lividipennis.CONCLUSIONSub-lethal concentrations of triazophos, deltamethrin and imidacloprid stimulated reproduction and enhanced population growth of C. lividipennis. The reproductive stimulation might result from the up-regulation of ClVg or ClSPATA13. These findings may be useful in mediating populations of planthoppers. © 2017 Society of Chemical Industry
      PubDate: 2017-02-10T04:11:29.749574-05:
      DOI: 10.1002/ps.4518
       
  • Efficacy of a long-lasting bifenthrin-treated net against horticultural
           pests and its compatibility with the predatory mite Amblyseius swirskii
           and the parasitic wasp Eretmocerus mundus
    • Authors: Maria del Mar Fernández; Ignacio Colomer, Pilar Medina, Alberto Fereres, Pedro Del Estal, Elisa Viñuela
      Abstract: BACKGROUNDInsecticide-treated nets (ITNs) have been investigated recently for their use in agriculture. Depending on the insecticide, the hole size and the way they are produced, these nets can target different pests and therefore they could be interesting options for use in integrated pest management (IPM). As the information on their compatibility with beneficial fauna is practically negligible, in this work we have tested the compatibility of an experimental bifenthrin long-lasting insecticide-treated net (LLITN) with Amblyseius swirskii and Eretmocerus mundus, important natural enemies of whiteflies and thrips, under laboratory, semi-field and commercial greenhouse conditions.RESULTSIn the laboratory, the treated net was very deleterious to adults of both natural enemies, after 72 h exposure. However, in choice tests with Y-tubes, both natural enemies were neither attracted nor repelled by the treated net and no short-term mortality was detected in individuals that had crossed it. No deleterious effects on the E. mundus beneficial capacity were detected in semi-field trials. In field trials, the LLITN proved to be compatible with A. swirskii while decreasing pest densities.CONCLUSIONSBifenthrin LLITN studied could be a valuable method for reducing pest population infestations in IPM programmes while being compatible with biocontrol agents. © 2017 Society of Chemical Industry
      PubDate: 2017-02-08T02:57:18.868834-05:
      DOI: 10.1002/ps.4515
       
  • Performance of honey bee colonies under a long-lasting dietary exposure to
           sub-lethal concentrations of the neonicotinoid insecticide thiacloprid
    • Authors: Reinhold Siede; Lena Faust, Marina D. Meixner, Christian Maus, Bernd Grünewald, Ralph Büchler
      Abstract: BACKGROUNDSubstantial honey bee colony losses have occurred periodically in the last decades. The drivers for these losses are not fully understood. The influence of pests and pathogens are beyond dispute, but in addition, chronic exposure to sub-lethal concentrations of pesticides has been suggested to affect the performance of honey bee colonies. This study aims to elucidate the potential effects of a chronic exposure to sub-lethal concentrations (one realistic worst-case concentration) of the neonicotinoid thiacloprid to honey bee colonies in a three-year replicated colony feeding study.RESULTSThiacloprid did not significantly affect the colony strength. No differences between treatment and control were observed for the mortality of bees, the infestation with the parasitic mite Varroa destructor and the infection levels of viruses. No colony losses occurred during the overwintering seasons. Furthermore, thiacloprid did not influence the constitutive expression of the immunity related hymenoptaecin gene. However, upregulating of the hymenoptaecin expression as a response to bacterial challenge was less pronounced in exposed bees than in control bees.CONCLUSIONUnder field conditions bee colonies are not adversely affected by a long-lasting exposure to sub-lethal concentrations of thiacloprid. No indications were found that field-realistic and higher doses exerted a biologically significant effect on colony performance.
      PubDate: 2017-02-07T04:50:28.145383-05:
      DOI: 10.1002/ps.4547
       
  • Effects of foliar and systemic insecticides on whitefly transmission and
           incidence of Cucurbit yellow stunting disorder virus
    • Authors: Steven Castle; John Palumbo, Paul Merten, Charles Cowden, Nilima Prabhaker
      Abstract: BACKGROUNDCucurbit yellow stunting disorder virus (CYSDV) is a cosmopolitan viral disease transmitted by Bemisia tabaci that infects cucurbit crops. Cantaloupe production in the southwestern USA has been confronted by epidemics of CYSDV since 2006 when it was first identified in Arizona and California. As a phloem-limited virus that is vectored in a semi-persistent manner by B. tabaci, CYSDV has transmission characteristics that may be suppressed by select insecticide applications.RESULTSEight active ingredients formulated as foliar and/or soil-applied insecticides were tested to determine the suppressive effect on transmission and incidence of CYSDV in greenhouse and field studies. Many compounds limited virus transmission to
      PubDate: 2017-02-07T03:50:45.352149-05:
      DOI: 10.1002/ps.4478
       
  • Discovery and characterisation of field resistance to organophosphorus
           chemicals in a major mite pest, Halotydeus destructor
    • Authors: Paul A Umina; Alan Lord, Svetlana Micic, Owain Edwards
      Abstract: BACKGROUNDThe redlegged earth mite (Halotydeus destructor) is an agricultural pest in Australia that attacks a wide variety of crops and pasture species. Chemicals remain an important part of control strategies for H. destructor, despite the existence of resistance to pyrethroid insecticides in this species. Recent chemical control failures involving a second insecticide class, organophosphates, were investigated using pesticide bioassays.RESULTSWe confirmed, for the first time, resistance to organophosphates in H. destructor, and show that resistance is not confined to a single property, or region. There was no evidence that resistance to organophosphorus chemicals has evolved in Australian states outside of Western Australia.CONCLUSIONThese findings demonstrate the strong evolutionary capability of H. destructor and highlight the need for ongoing resistance surveillance within Australia. © 2017 Society of Chemical Industry
      PubDate: 2017-02-07T03:10:29.220398-05:
      DOI: 10.1002/ps.4520
       
  • Impact of glyphosate-resistant sugar beet
    • Authors: Don W Morishita
      Abstract: Glyphosate-resistant (GR) sugar beet became commercially available to US sugar beet growers in 2008 and was rapidly adopted. Prior to the availability of GR sugar beet, growers would commonly make 3–5 herbicide applications. This often resulted in some crop injury, but was accepted to reduce the impact of weeds. In addition, non-GR sugar beet was cultivated 1–3 times and often followed by hand weeding. The introduction of GR sugar beet drastically reduced the complexity of weed management. Concerns about GR weeds in the United States also apply to sugar beet growers. Changes in weed management strategies will be required to keep this technology. Sugar beet is arguably one of the most suitable crops for GR technology because: (1) none of the herbicides registered for use in this crop was very effective without risking crop injury; (2) sugar beet cannot be grown in the same field year after year owing to disease concerns and thus requires a 3–4 year rotation; (3) pollen-mediated gene flow is negligible from the sugar beet crop because it is a biennial and harvested before it flowers; (4) the processing of harvested roots to extract the sucrose rapidly degrades the DNA in the extracted raw juice and subsequent refining so that no DNA is present in the finished sugar; (5) studies have shown that processed GR beet sugar is identical to non-GR beet sugar, as well as cane sugar. © 2016 Society of Chemical Industry
      PubDate: 2017-02-06T08:40:25.281935-05:
      DOI: 10.1002/ps.4503
       
  • Cross-resistance to three phenylpyrazole insecticides and A2′N mutation
           detection of GABA receptor subunit in fipronil-resistant Laodelphax
           striatellus (Hemiptera: Delphacidae)
    • Authors: Qi Wei; Xi-Chao Mu, Shun-Fan Wu, Li-Xiang Wang, Cong-Fen Gao
      Abstract: BACKGROUNDLaodelphax striatellus (Fallén) is an important pest of crops in East Asia. Over the past decade, phenylpyrazole insecticides, which target the insect GABA receptor, have increasingly been used as alternatives against rice planthoppers.RESULTSCross-resistance to ethiprole and butene-fipronil was detected in a laboratory-selected fipronil-resistant strain of L. striatellus (LsFR). Compared with a fipronil-susceptible strain (LsFS), LsFR had obtained a high-level resistance to fipronil (112.1-fold) and moderate resistance to ethiprole (24.5-fold) and butene-fipronil (14.7-fold). For the resistance of field populations, LC50 values of ethiprole were remarkably higher than the other two analogues in Gaochun and Yancheng populations in 2016. Significant correlations were demonstrated between the LC50 values of three phenylpyrazole insecticides (R = 0.944-0.998, P = 0.007–0.016). Additionally, an AS-PCR assay was developed to detect the A2′N mutant GABA receptor in L. striatellus strains or populations. It was noteworthy that mutation frequencies of 19.2 and 3.6% appeared in Lujiang and Gaochun populations in 2016, respectively. Furthermore, there was an extremely significant difference in genomic expression of Lsrdl between the LsFS and LsFR individuals (1.85-fold, F = 26.8, P = 0.0008).CONCLUSIONSThis study could help us better understand the cross-resistance mechanisms in L. striatellus, and be beneficial for proposing effective pest management strategies of phenylpyrazole resistance. © 2016 Society of Chemical Industry
      PubDate: 2017-02-06T03:50:35.029015-05:
      DOI: 10.1002/ps.4498
       
  • Winter flooding of California rice fields reduces immature populations of
           Lissorhoptrus oryzophilus (Coleoptera: Curculionidae) in the spring
    • Authors: Mohammad-Amir Aghaee; Larry D Godfrey
      Abstract: BACKGROUNDIn California, rice fields are flooded over the winter months (November to March) to facilitate degradation of post-harvest rice straw and to provide temporary habitat for migratory waterfowl. Prior research showed that winter flood rice fields had fewer rice water weevil (Lissorhoptrus oryzophilus), larvae and pupae during the rice production season than fields that were left unflooded in the winter. A series of experiments were conducted to provide further support for these trends under controlled conditions and to find a mechanism for this phenomenon.RESULTSUnder winter flooded conditions there was a 50% reduction in populations of weevil immatures compared with the untreated control (no straw or winter flood). These same conditions corresponded to a 20% increase in the amount of silicon found in plant tissues in 2014 and a 39 to 90% decrease in methane production in the soil from 2013 to 2014, respectively.CONCLUSIONEvidence from previous field research and these controlled studies supports winter flooding as an appropriate tactic for controlling L. oryzophilus populations in the spring. However, the mechanism that would explain why winter flooding adversely affects L. oryzophilus immatures remains unclear. © 2016 Society of Chemical Industry
      PubDate: 2017-02-06T03:50:27.672372-05:
      DOI: 10.1002/ps.4507
       
  • Tetra-primer ARMS PCR for rapid detection and characterisation of
           Plasmopara viticola phenotypes resistant to carboxylic acid amide
           fungicides
    • Authors: Hao Zhang; Fanfang Kong, Xina Wang, Lisha Liang, Cor D Schoen, Jie Feng, Zhongyue Wang
      Abstract: BACKGROUNDThe occurrence of Plasmopara viticola populations resistant to carboxylic acid amide (CAA) fungicides is becoming a serious problem in the control of grapevine downy mildew worldwide. The resistance is caused by point mutations in the PvCesA3 gene. These isolates with this mutation have been detected mainly by determining the minimum inhibitory concentration of fungicides, which is always time consuming and inefficient.RESULTSTo establish a suitable method for rapid detection of the G1105S mutation in P. viticola, an efficient and simple molecular method was developed, based on tetra-primer ARMS PCR. A set of four primers were designed and optimised to distinguish the different genotypes within one step. Only 2 h was required from the sampling of symptoms to the phenotyping of fungicide resistance. Using this method, CAA-resistant P. viticola were identified for the first time in China. Also, the finding of sensitive heterozygotes indicated that the resistant allele is spreading in the population in Ziyuan.CONCLUSIONThis new method proved to be useful as an early warning system for resistance outbreaks of P. viticola to CAA fungicides in the field and may be helpful in decisions concerning rotation of different fungicide groups. © 2016 Society of Chemical Industry
      PubDate: 2017-02-03T12:05:41.063024-05:
      DOI: 10.1002/ps.4506
       
  • Novel Gene-Sequence Markers for Isolate Tracking within Monilinia
           fructicola Lesions
    • Authors: M.E. Dowling; G. Schnabel, H.G. Boatwright, S.E. Everhart
      Abstract: ABSTRACTDowling, M.E., Schnabel, G., Boatwright, H.G., and Everhart, S.E. xxxx. Novel gene-sequence markers for isolate tracking within Monilinia fructicola lesions. Pest Management Science xxx:xxx-xxx.BACKGROUNDMonilinia fructicola is a diverse pathogen of pome and stone fruits that causes severe economic losses each year. However, little is known about inoculum flow within or between orchards and pathogen establishment in an orchard, because few methods exist for detecting diversity or tracking isolates over time. SSR loci are an effective option, but may be confounded by a high degree of mutability and potential sensitivity to abiotic stress.RESULTSThrough transcriptome analysis, we identified novel markers mrr1, DHFR, and MfCYP01 and validated stability of these markers under fungicide stress in natural infection sites. Nucleotide variation within mrr1, DHFR, and MfCYP01 sequences differentiated isolates at all spatial scales: within the same infection site, between trees, and between two farms. Sequenced regions were also effective for matching isolates collected from blossoms at the beginning of the season to progeny in cankers obtained at the end of the season.CONCLUSIONSCollectively, results show that mrr1, DHFR, and MfCYP01 are able to accurately differentiate M. fructicola isolates at the population level, can be used to track isolates over time, and are more stable than SSRs under external stresses. Either by themselves or combined with SSR markers, these gene-encoding regions are a much-needed tool for better understanding M. fructicola population dynamics.
      PubDate: 2017-02-03T07:50:35.511775-05:
      DOI: 10.1002/ps.4544
       
  • How the use of nitrogen fertiliser may switch plant suitability for
           aphids: the case of Miscanthus, a promising biomass crop, and the aphid
           pest Rhopalosiphum maidis
    • Authors: Florent Bogaert; Quentin Chesnais, Manuella Catterou, Caroline Rambaud, Géraldine Doury, Arnaud Ameline
      Abstract: BACKGROUNDThe use of nitrogen fertiliser in agrosystems can alter plant nitrogen and consequently improve nutrient availability for herbivores, potentially leading to better performance for herbivores and higher pest pressure in the field. We compared, in laboratory conditions, the effects of nitrogen fertilisation on a promising biomass crop, Miscanthus × giganteus, and its parents M. sinensis and M. sacchariflorus. The plant-mediated effects were compared on the second trophic level, the green corn leaf aphid Rhopalosiphum maidis.RESULTSResults showed that the biomass and leaf C:N ratio of M. sinensis plants treated with nitrogen fertiliser were significantly greater than those of non-treated plants. As regards M. × giganteus and M. sacchariflorus, the only reported change was a significantly smaller leaf C:N ratio for treated M. sacchariflorus compared with non-treated plants. Surprisingly, nitrogen fertilisation had opposite effects on plant–herbivore interactions. Following nitrogen treatments, M. sinensis was less suitable in terms of intrinsic rate of increase for R. maidis, the feeding behaviour of which was negatively affected, while M. sacchariflorus and M. × giganteus exhibited greater suitability in terms of aphid weight.CONCLUSIONNitrogen fertilisation had contrasting effects on the three species of Miscanthus plants. These effects cascaded up to the second trophic level, R. maidis aphid pests, either through a modification of their weight or demographic parameters. The implications of these results were discussed in the context of agricultural sustainability and intensive production practices. © 2016 Society of Chemical Industry
      PubDate: 2017-02-03T03:35:27.928119-05:
      DOI: 10.1002/ps.4505
       
  • Numerical simulation of ozone concentration profile and flow
           characteristics in paddy bulks
    • Authors: Ravi Pandiselvam; Veerapandian Chandrasekar, Venkatachalam Thirupathi
      Abstract: BACKGROUNDOzone has shown the potential to control stored product insect pests. The high reactivity of ozone leads to special problems when it passes though an organic medium such as stored grains. Thus, there is a need for a simulation study to understand the concentration profile and flow characteristics of ozone in stored paddy bulks as a function of time.RESULTSSimulation of ozone concentration through the paddy grain bulks was explained by applying the principle of the law of conservation along with a continuity equation. A higher ozone concentration value was observed at regions near the ozone diffuser whereas a lower concentration value was observed at regions away from the ozone diffuser. The relative error between the experimental and predicted ozone concentration values for the entire bin geometry was less than 42.8%.CONCLUSIONThe simulation model described a non-linear change of ozone concentration in stored paddy bulks. Results of this study provide a valuable source for estimating the parameters needed for effectively designing a storage bin for fumigation of paddy grains in a commercial scale continuous-flow ozone fumigation system. © 2017 Society of Chemical Industry
      PubDate: 2017-02-03T03:25:28.911475-05:
      DOI: 10.1002/ps.4516
       
  • Evaluation of a decision support strategy for the control of powdery
           mildew (Erysiphe necator [Schw.] Burr.) in grapevine in the central region
           of Chile
    • Authors: Héctor Valdés-Gómez; Miguel Araya-Alman, Carolina Pañitrur-De la Fuente, Nicolás Verdugo-Vásquez, Mauricio Lolas, César Acevedo-Opazo, Christian Gary, Agnès Calonnec
      Abstract: BACKGROUNDThe primary strategy to control powdery mildew in Chilean vineyards involves periodic fungicide spraying, which may lead to many environmental and human health risks. This study aimed to implement and evaluate the effectiveness and economic feasibility of a novel Decision Support Strategy (DSS) to limit the number of treatments against this pathogen. An experiment was conducted between the 2010 and 2013 seasons in two irrigated vine fields, one containing a cultivar of Cabernet Sauvignon (CS) and another of Chardonnay (CH).RESULTSThe results showed that the DSS effectively controlled powdery mildew in CS and CH vine fields as evidenced by a disease severity lower than 3%, which was lower than that observed in untreated vines (approximately 10% and 40 % for CS and CH, respectively). The DS strategy required the application of only 2–3 fungicide treatments per season in key vine phenological stages, and the cost fluctuated between US $ 322 and 415 per hectare, which was 40 to 60 % cheaper than the traditional strategy employed by vine growers.CONCLUSIONThe Decision Support Strategy evaluated in this trial allows a good control of powdery mildew for various types of epidemics with an early and late initiation.
      PubDate: 2017-02-03T01:15:33.327236-05:
      DOI: 10.1002/ps.4541
       
  • Pesticide exposure assessment for surface waters in the EU. Part 2:
           Determination of statistically based run-off and drainage scenarios for
           Germany
    • Authors: Martin Bach; Mirjam Diesner, Dietlinde Großmann, Djamal Guerniche, Udo Hommen, Michael Klein, Roland Kubiak, Alexandra Müller, Thomas G Preuss, Jan Priegnitz, Stefan Reichenberger, Kai Thomas, Matthias Trapp
      Abstract: BACKGROUNDIn order to assess surface water exposure to active substances of plant protection products (PPPs) in the European Union (EU), the FOCUS (FOrum for the Co-ordination of pesticide fate models and their USe) surface water workgroup introduced four run-off and six drainage scenarios for Step 3 of the tiered FOCUSsw approach. These scenarios may not necessarily represent realistic worst-case situations for the different Member States of the EU. Hence, the suitability of the scenarios for risk assessment in the national authorisation procedures is not known.RESULTSUsing Germany as an example, the paper illustrates how national soil–climate scenarios can be developed to model entries of active substances into surface waters from run-off and erosion (using the model PRZM) and from drainage (using the model MACRO). In the authorisation procedure for PPPs on Member State level, such soil–climate scenarios can be used to determine exposure endpoints with a defined overall percentile.CONCLUSIONThe approach allows the development of national specific soil–climate scenarios and to calculate percentile-based exposure endpoints. The scenarios have been integrated into a software tool analogous to FOCUS-SWASH which can be used in the future to assess surface water exposure in authorisation procedures of PPPs in Germany. © 2017 The
      Authors . Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
      PubDate: 2017-02-01T04:00:43.310365-05:
      DOI: 10.1002/ps.4519
       
  • Improved synthetic route to quinoxyfen photometabolite
           2-chloro-10-fluorochromeno[2,3,4-de]quinoline
    • Authors: Peter L Johnson; Jeremy Kister, Scott Thornburgh
      Abstract: BACKGROUNDQuinoxyfen is a fungicide developed by Dow AgroSciences for the control of powdery mildew. Re-registration studies required gram quantities of 2-chloro-10-fluorochromeno[2,3,4-de]quinoline, a photometabolite of quinoxyfen. The only previous method of preparation of this photometabolite was by photolysis of quinoxyfen in less than 1% yield. Therefore, a new method allowing for the preparation of this photometabolite in gram quantities was required.RESULTSSeveral different metal catalyzed intramolecular cyclization approaches were investigated for the synthesis of 2-chloro-10-fluorochromeno[2,3,4-de]quinoline. While most methods failed to provide the desired product from a 2-bromophenyl derivative of quinoxyfen, a novel one-pot two-step synthesis led to the desired material in good yield from quinoxyfen.CONCLUSIONA short and efficient synthetic route was developed to access 2-chloro-10-fluorochromeno[2,3,4-de]quinoline from readily available (4-fluoro-2-hydroxyphenyl)boronic acid and quinoxyfen and was found to be scalable, which enabled the preparation of the desired photometabolite in gram quantities thus meeting material requirements to complete regulatory studies for the re-registration of quinoxyfen. © 2017 Society of Chemical Industry
      PubDate: 2017-02-01T03:55:42.708937-05:
      DOI: 10.1002/ps.4517
       
  • Mortality, fecundity and development among bed bugs (Cimex lectularius)
           exposed to prolonged, intermediate cold stress
    • Authors: Bjørn A Rukke; Morten Hage, Anders Aak
      Abstract: BACKGROUNDBed bugs (Cimex lectularius L.) have returned as a nuisance pest worldwide. Their ability to withstand different types of environmental stress should be explored in order potentially to increase the efficiency of control methods.RESULTSImmediate and long-term effects of exposure to temperatures from 0 to −10 °C for 1, 2 and 3 weeks are reported. Fifth-instar nymphs and adults were exposed to constant or fluctuating temperatures. Increased cold and extended time yielded higher mortality; nymphs were more resilient than adults at the shorter durations of exposure. At intermediate temperatures, mortality was higher at constant compared with fluctuating temperatures, whereas all individuals died after 3 weeks of exposure to −7 °C. The success among survivors after cold treatment was also affected in terms of reduced egg production, hatching success and the ability of fifth-instar nymphs to advance into the adult stage; however, nymphs produced after cold treatment developed normally.CONCLUSIONSDetrimental effects of prolonged exposure to low temperatures were seen in bed bugs both during and after cold treatment. The results suggest that temperatures below −7 °C can be applied by laymen to control this pest in small items if available treatment time is of less concern. © 2016 The
      Authors . Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
      PubDate: 2017-01-31T03:26:01.012955-05:
      DOI: 10.1002/ps.4504
       
  • How glyphosate affects plant disease development: it is more than enhanced
           susceptibility
    • Authors: Ray Hammerschmidt
      Abstract: Glyphosate has been shown to affect the development of plant disease in several ways. Plants utilize phenolic and other shikimic acid pathway-derived compounds as part of their defense against pathogens, and glyphosate inhibits the biosynthesis of these compounds via its mode of action. Several studies have shown a correlation between enhanced disease and suppression of phenolic compound production after glyphosate. Glyphosate-resistant crop plants have also been studied for changes in resistance as a result of carrying the glyphosate resistance trait. The evidence indicates that neither the resistance trait nor application of glyphosate to glyphosate-resistant plants increases susceptibility to disease. The only exceptions to this are cases where glyphosate has been shown to reduce rust diseases on glyphosate-resistant crops, supporting a fungicidal role for this chemical. Finally, glyphosate treatment of weeds or volunteer crops can cause a temporary increase in soil-borne pathogens that may result in disease development if crops are planted too soon after glyphosate application. © 2017 Society of Chemical Industry
      PubDate: 2017-01-30T08:45:40.912818-05:
      DOI: 10.1002/ps.4521
       
  • A beekeeper's perspective on the neonicotinoid ban
    • Authors: Norman L Carreck
      Abstract: Bees and agrochemicals have a long history. For example, the first volume of IBRA's journal Bee World in 1919 contains mention of poisoning of bees by spraying an orchard with lead arsenate. Bees being insects, it is self-evident that the use of insecticides to control crop pests poses a risk to them. Bee poisoning incidents became a very serious problem in the 1960s and 1970s with spraying of, in particular, oilseed rape with organophosphorus compounds. The introduction of carbamates and then especially synthetic pyrethroids reduced these problems. Data from the Wildlife Incident Investigation Scheme show that in recent years there have been very few poisoning incidents in the United Kingdom that can be attributed to agricultural insecticides. The introduction of neonicotinoid insecticides has, however, been very controversial. Almost as soon as they were introduced in the 1990s, French beekeepers blamed colony losses on imidacloprid used on sunflowers and maize, but restrictions on its use did not lead to a reduction in losses or to a reduction in beekeepers' concerns. Acute pesticide poisoning incidents by neonicotinoids in Germany and Italy in 2008 further sealed their reputation. Despite laboratory evidence showing their harm, field experience remains equivocal, and many commercial beekeepers continue to move their colonies to oilseed rape crops for honey production. The neonicotinoid moratorium has undoubtedly led to the increased use of older insecticides, and the effect of this on bee populations is unknown and unquantified. Many beekeepers are currently confused by the conflicting evidence. © 2016 Society of Chemical Industry
      PubDate: 2017-01-30T04:38:07.971509-05:
      DOI: 10.1002/ps.4489
       
  • Discovery of metabolic resistance to neonicotinoids in green peach aphids
           (Myzus persicae) in Australia
    • Authors: Siobhan C de Little; Owain Edwards, Anthony R van Rooyen, Andrew Weeks, Paul A Umina
      Abstract: BACKGROUNDMyzus persicae is a serious pest that attacks a broad range of agricultural crops. This species has developed chemical resistance to many insecticides globally, and within Australia resistance to multiple chemical groups has been identified. Resistance to neonicotinoid insecticides has been discovered in several countries, but has not previously been confirmed in Australia. We use biomolecular assays and bioassays on field-collected populations to investigate neonicotinoid resistance in M. persicae within Australia.RESULTSSeveral geographically and genetically distinct populations showed evidence for resistance in bioassays. Genetic markers identified that the mechanism of neonicotinoid resistance in Australia is metabolic resistance through the enhanced expression of a cytochrome P450 gene, CYP6CY3.CONCLUSIONM. persicae populations in parts of Australia are now resistant to four different insecticide chemical groups, raising concerns about the long-term management of this pest. While higher copy numbers of CYP6CY3 were seen in all resistant populations, the number of gene copies was not strongly correlated with the level of resistance as determined by LD50 values generated through bioassays. This finding sheds further light on the complexity of the P450 genes in regulating neonicotinoid resistance. © 2016 Society of Chemical Industry
      PubDate: 2017-01-30T04:29:56.22155-05:0
      DOI: 10.1002/ps.4495
       
  • Phytoecdysteroids as antifeedants towards several beetles that include
           polyphagous and monophagous feeding guilds
    • Authors: Russell Jurenka; Kathryn Russell, Matthew O'Neal
      Abstract: BACKGROUNDPlants are thought to produce ecdysteroids as a means of protection from insect herbivores. Some insects will not feed on plants containing high amounts of phytoecdysteroids, and this response could be limited to monophagous and oligophagous insects. The aim of this study was to determine whether phytoecdysteroids could inhibit feeding in several species of beetles that range from monophagous to polyphagous.RESULTSHere we demonstrate that phytoecdysteroids, including 20-hydroxyecdysone, prevent several beetle species from feeding on preferred host plants, including the polyphagous Japanese beetle Popillia japonica (Scarabaeidae). Phytoecdysteroids prevented feeding damage when sprayed onto soybean plants in no-choice and choice assays in a dose-dependent manner. Laboratory assays indicate that other plants could be protected from Japanese beetle herbivory, including linden, wild grape, elm, Virginia creeper and rose leaves. Additional beetle species tested in the family Chrysomelidae included the oligophagous Cerotoma trifurcata and Diabrotica virgifera virgifera and the monophagous Trirhabda canadensis. All species were prevented from feeding when their preferred host plants were treated with phytoecdysteroids.CONCLUSIONThis study demonstrates that beetles, representing polyphagous and monophagous feeding guilds, can be prevented from feeding when phytoecdysteroids are applied to the leaf surface. The phytoecdysteroids could be utilized in pest management towards a variety of beetles, including the more pestiferous polyphagous species, if the compounds are placed on the leaf surface. © 2016 Society of Chemical Industry
      PubDate: 2017-01-26T06:05:27.741976-05:
      DOI: 10.1002/ps.4500
       
  • MicroRNA and dsRNA targeting chitin synthase A reveal a great potential
           for pest management of the hemipteran insect Nilaparvata lugens
    • Authors: Tengchao Li; Jie Chen, Xiaobin Fan, Weiwen Chen, Wenqing Zhang
      Abstract: BACKGROUNDTwo RNA silencing pathways in insects are known to exist that are mediated by short interfering RNAs (siRNAs) and microRNAs (miRNAs), which have been hypothesised to be promising methods for insect pest control. However, a comparison between miRNA and siRNA in pest control is still unavailable, particularly in targeting chitin synthase gene A (CHSA).RESULTSThe dsRNA for Nilaparvata lugens CHSA (dsNlCHSA) and the microR-2703 (miR-2703) mimic targeting NlCHSA delivered via feeding affected the development of nymphs, reduced their chitin content and led to lethal phenotypes. The protein level of NlCHSA was downregulated after female adults were injected with dsNlCHSA or the miR-2703 mimic, but there were no significant differences in vitellogenin (NlVg) expression or in total oviposition relative to the control group. However, 90.68 and 46.13% of the eggs laid by the females injected with dsNlCHSA and miR-2703 mimic were unable to hatch, respectively. In addition, a second-generation miRNA and RNAi effect on N. lugens was observed.CONCLUSIONIngested miR-2703 seems to be a good option for killing N. lugens nymphs, while NlCHSA may be a promising target for RNAi-based pest management. These findings provide important evidence for applications of small non-coding RNAs (snRNAs) in insect pest management. © 2016 Society of Chemical Industry
      PubDate: 2017-01-26T05:45:29.867124-05:
      DOI: 10.1002/ps.4492
       
  • Economic analysis of revenue losses and control costs associated with the
           spotted wing drosophila, Drosophila suzukii (Matsumura), in the California
           raspberry industry
    • Authors: Derek Farnsworth; Kelly A Hamby, Mark Bolda, Rachael E Goodhue, Jeffrey C Williams, Frank G Zalom
      Abstract: BACKGROUNDThe spotted wing drosophila (SWD), Drosophila suzukii (Matsumura), is an invasive vinegar fly with a preference for infesting commercially viable berries and stone fruits. SWD infestations can reduce yields significantly, necessitating additional management activities. This analysis estimates economic losses in the California raspberry industry that have resulted from the SWD invasion.RESULTSCalifornia raspberry producers experienced considerable revenue losses and management costs in the first years following SWD's invasion of North America. Conventional producers have since developed effective chemical management programs, virtually eliminating revenue losses due to SWD and reducing the cost of management to that of purchasing and applying insecticides more often. Organic raspberry producers, who do not have access to the same chemical controls, continue to confront substantial SWD-related revenue losses. These losses can be mitigated only by applying expensive insecticides registered for organic use and by performing labor-intensive field sanitation.CONCLUSIONSWD's invasion into North America has caused extensive crop losses to berry and cherry crops in California and elsewhere. Agricultural producers and researchers have responded quickly to this pest by developing management programs that significantly reduce revenue losses. Economic losses are expected to continue to fall as producers learn to manage SWD more efficiently and as new control tactics become available. © 2016 Society of Chemical Industry
      PubDate: 2017-01-26T04:56:12.003043-05:
      DOI: 10.1002/ps.4497
       
  • Development of a mechanical sexing system to improve the efficacy of an
           area-wide sterile insect release programme to control American serpentine
           leafminer (Diptera: Agromyzidae) in Canadian ornamental greenhouses
    • Authors: Maryam Sultan; Rose Buitenhuis, Graeme Murphy, Cynthia D Scott-Dupree
      Abstract: BACKGROUNDAmerican serpentine leafminer (ASL), Liriomyza trifolii (Burgess), is a significant pest of greenhouse ornamental crops, and females damage leaf tissue with their ovipositor during feeding and oviposition. The sterile insect technique has been advocated as a non-chemical alternative to currently available control methods. In area-wide sterile insect release programmes, males act as true vectors of sterility. Females should be eliminated from a cohort of pupae prior to irradiation to maximise production economics and sterility spread. The aim of this research was to develop a mechanical sexing system based on pupal size to reduce the proportion of ASL females.RESULTSCumulative frequency distributions were used to examine significant differences in male and female pupal length and dorsal and lateral width distributions. Optimum size cut-off points based on the largest differences in distribution curves were used to determine the dimensions of three different sieve designs. Sieve pores measuring 1.543 mm by 0.765 mm excluded 76% of female pupae and doubled the proportion of males in the throughput sample.CONCLUSIONPupal sexual dimorphisms identified in this research can be used to design a sieve to aid in reducing the proportion of females prior to irradiation, thus improving the efficacy of an area-wide sterile insect release programme. © 2016 Society of Chemical Industry
      PubDate: 2017-01-25T03:20:31.627872-05:
      DOI: 10.1002/ps.4494
       
  • Imidacloprid seed treatments affect individual ant behavior and community
           structure but not egg predation, pest abundance or soybean yield
    • Authors: Hannah J Penn; Andrew M Dale
      Abstract: BACKGROUNDNeonicotinoid seed treatments are under scrutiny because of their variable efficacy against crop pests and for their potential negative impacts on non-target organisms. Ants provide important biocontrol services in agroecosystems and can be indicators of ecosystem health. This study tested for effects of exposure to imidacloprid plus fungicide or fungicide-treated seeds on individual ant survival, locomotion and foraging capabilities and on field ant community structure, pest abundance, ant predation and yield.RESULTSCohorts of ants exposed to either type of treated seed had impaired locomotion and a higher incidence of morbidity and mortality but no loss of foraging capacity. In the field, we saw no difference in ant species richness, regardless of seed treatment. Blocks with imidacloprid did have higher species evenness and diversity, probably owing to variable effects of the insecticide on different ant species, particularly Tetramorium caespitum. Ant predation on sentinel eggs, pest abundance and soybean growth and yield were similar in the two treatments.CONCLUSIONBoth seed treatments had lethal and sublethal effects on ant individuals, and the influence of imidacloprid seed coating in the field was manifested in altered ant community composition. Those effects, however, were not strong enough to affect egg predation, pest abundance or soybean yield in field blocks. © 2016 Society of Chemical Industry
      PubDate: 2017-01-23T08:20:50.37416-05:0
      DOI: 10.1002/ps.4499
       
  • Field evaluation of 3-hydroxy-2-hexanone and ethanol as attractants for
           the cerambycid beetle pest of vineyards, Xylotrechus arvicola
    • Authors: Álvaro Rodríguez-González; Esteban Sánchez-Maíllo, Horacio J Peláez, Manuel González-Núñez, David R Hall, Pedro A Casquero
      Abstract: BACKGROUNDThe beetle Xylotrechus arvicola (Coleoptera: Cerambycidae) is a serious pest of vineyards in the Iberian Peninsula. In previous work, the male beetles, but not females, were shown to produce (R)-3-hydroxy-2-hexanone, and female beetles were attracted to this compound in a laboratory bioassay. In this study, release rates of 3-hydroxy-2-hexanone from different dispensers were measured in the laboratory, and the attractiveness of these to X. arvicola adults was determined in trapping tests in three traditional wine-growing regions in Spain.RESULTSAs a result of laboratory experiments, for field experiments 3-hydroxy-2-hexanone was formulated as 100 μL in a polyethylene sachet (50 mm × 50 mm × 250 µm), and ethanol was formulated as 1 mL in a polyethylene press-seal bag (76 mm × 57 mm ×50 µm). Field catches were similar at all three study sites. Catches in traps baited with 3-hydroxy-2-hexanone alone were not significantly different from those in unbaited control traps, but catches in traps baited with 3-hydroxy-2-hexanone and ethanol in separate sachets, with 3-hydroxy-2-hexanone and ethanol in the same sachet or with ethanol alone were significantly greater than those in control traps. These results confirm that the beetles are attracted to ethanol, and the addition of 3-hydroxy-2-hexanone does not seem to make any difference.CONCLUSIONSAttraction of females for the male-produced compound (R)-3-hydroxy-2-hexanone has been observed in laboratory but not in field experiments. Traps baited with ethanol are highly attractive to both sexes of adults of X. arvicola, and these can be used for improved monitoring of the adult emergence and for population control by mass trapping. © 2016 Society of Chemical Industry
      PubDate: 2017-01-19T04:40:55.991384-05:
      DOI: 10.1002/ps.4491
       
  • An entomopathogenic bacterium strain, Bacillus thuringiensis, as a
           biological control agent against the red palm weevil, Rhynchophorus
           ferrugineus (Coleoptera: Curculionidae)
    • Authors: Yu-chen Pu; Tian-ling Ma, You-ming Hou, Ming Sun
      Abstract: BACKGROUNDThe red palm weevil (RPW), Rhynchophorus ferrugineus, is an invasive wood-boring insect that damages palms and sugarcane. Bacillus thuringiensis (Bt) is an entomopathogenic bacterium which has been modified into various strains and widely used in pest management. The aim of this study was to evaluate the susceptibility of RPW to the HA strain of Bt.RESULTSFive concentrations of Bt bioassays were used on RPW eggs, second instars and fourth instars. Average egg hatching rates exceeded 85% using Bt suspensions or distilled water. Hatch times were extended significantly using higher Bt concentrations. For second instar larvae, the LC50 was 4.92 × 109 CFU mL−1 15 d after feeding; the LT50 values decreased with each higher concentration. The corrected mortality of second instars increased significantly with increased concentrations after 15 d, ranging from 16.97% to 94.32%. Significant differences occurred in the boring activity of fourth instars when dipped in Bt suspensions or crawling on treated sugarcane. Bacterial infection in dead larvae was confirmed using molecular techniques.CONCLUSIONOur results indicated that Bt can be used in RPW control as a potential biological control agent and can effectively reduce palm trees damage. © 2016 Society of Chemical Industry
      PubDate: 2017-01-06T03:35:37.420713-05:
      DOI: 10.1002/ps.4485
       
  • Enhanced photosynthesis endows seedling growth vigour contributing to the
           competitive dominance of weedy rice over cultivated rice
    • Authors: Lei Dai; Xiaoling Song, Baoye He, Bernal E Valverde, Sheng Qiang
      Abstract: BACKGROUNDWeedy rice, as one of the worst paddy field weeds worldwide, bears vigorous seedlings and dominantly competes with cultivated rice causing serious crop yield losses. To elucidate the causes of its stronger seedling vigour endowing its dominant competition with cultivated rice, comparative studies on seedling growth characteristics were conducted among six weedy rice biotypes and the two indica and japonica cultivars Shanyou-63 (SY-63) and Zhendao-8 (ZD-8), respectively, in the greenhouse.RESULTSWeedy rice emerged 2 to 3 days earlier, rapidly grew 1.3–1.7 cm taller daily, produced more secondary adventitious roots and greater aboveground fresh biomass than cultivated rice. Moreover, weedy rice exhibited greater photosynthetic pigment content, net photosynthetic rate, stomatal conductance, intercellular CO2 concentration, transpiration rate, and chlorophyll fluorescence kinetic parameters. An enhanced overall photosynthetic activity in weedy rices was attributed to the combined action of a larger antenna, more active reaction centres and higher quantum yield for electron transfer beyond QA.CONCLUSIONSEnhanced photosynthesis of weedy rice at the seedling stage should be the main factor for leading to strong competitive dominance over cultivated rice. © 2016 Society of Chemical Industry
      PubDate: 2017-01-05T10:45:49.405755-05:
      DOI: 10.1002/ps.4471
       
  • Dibenzo-α-pyrones: a new class of larvicidal metabolites against Aedes
           aegypti from the endophytic fungus Hyalodendriella sp. Ponipodef12
    • Authors: Ziling Mao; Daowan Lai, Xunda Liu, Xiaoxiang Fu, Jiajia Meng, Ali Wang, Xiaohan Wang, Weibo Sun, Zhi Long Liu, Ligang Zhou, Yang Liu
      Abstract: BACKGROUNDIn our search for new agrochemicals from endophytic fungi, the crude extract of the endophytic Hyalodendriella sp. Ponipodef12 associated with the hybrid ‘Neva’ of Populus deltoides Marsh × P. nigra L. was found to possess larvicidal activity against Aedes aegypti.RESULTSFractionation of the extract has led to the isolation of 11 dibenzo-α-pyrones (1–11), including three new congeners: hyalodendriols A–C (1–3). The structures of the new compounds were elucidated by comprehensive spectroscopic analyses, including the modified Mosher's method for the assignment of the absolute configuration. Compounds 2–7 showed potent larvicidal activities against the fourth-instar larvae of A. aegypti with IC50 values ranging from 7.21 to 120.81 µg mL−1. Among them, penicilliumolide D (6) displayed the strongest activity (IC50 = 7.21 µg mL−1). A structure–larvicidal activity relationship was discussed. The possible mode of action of these compounds was assessed for their acetylcholinesterase inhibitory activities. In addition, hyalodendriol C (3) displayed antibacterial activity against Bacillus subtilis and Xanthomonas vesicatoria, and exhibited strong inhibition against the spore germination of Magnaporthe oryzae.CONCLUSIONOur study revealed dibenzo-α-pyrones to be a new class of larvicidal metabolites against A. aegypti. © 2016 Society of Chemical Industry
      PubDate: 2017-01-05T04:05:31.804349-05:
      DOI: 10.1002/ps.4481
       
  • Issue Information
    • Pages: 651 - 654
      PubDate: 2017-03-01T02:18:09.291752-05:
      DOI: 10.1002/ps.4382
       
  • Innovations in Agrochemical Discovery and the Role of Metabolism,
           Bioavailability and Formulations
    • Authors: Beth A Lorsbach; Thomas C Sparks
      Pages: 655 - 657
      PubDate: 2017-03-01T02:18:05.899425-05:
      DOI: 10.1002/ps.4533
       
  • Chance and design in proinsecticide discovery
    • Authors: Vincent L Salgado; Michael D David
      Pages: 723 - 730
      Abstract: Many insecticides are inactive on their target sites in the form that is sold and applied, needing first to be bioactivated. This proinsecticide strategy has often been achieved by design, through systematic derivatization of intrinsically active molecules with protecting groups that mask their toxic effects until their selective removal in target insects by metabolic enzymes generates the toxiphore. Proinsecticides can be designed to gain selectivity between target and non-target organisms, or to improve bioavailability by enhancing plant or insect uptake. In most cases, however, chance trumps design in proinsecticide discovery: most first-in-class products that we now know to be proinsecticides were only discovered a posteriori to be such, often after having been on the market for years. Knowing the active form of an insecticide is essential to mode of action identification, and early mode of action studies on novel chemotypes should take into account the possibility that the compounds might be proinsecticides. This paper reviews examples of proinsecticides in the marketplace, strategies for making proinsecticides and techniques for unmasking proinsecticides in mode of action studies. Our analysis of global agrochemical sales data shows that 34% of the dollar value of crop insecticides used in 2015 were proinsecticides. © 2016 Society of Chemical Industry
      PubDate: 2017-02-02T03:21:10.053066-05:
      DOI: 10.1002/ps.4502
       
  • Synthesis and biological activity of pyridazine amides, hydrazones and
           hydrazides
    • Authors: Ann M Buysse; Maurice CH Yap, Ricky Hunter, Jonathan Babcock, Xinpei Huang
      Pages: 782 - 795
      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 exist 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. © 2016 Society of Chemical Industry
      PubDate: 2017-01-30T04:16:20.542774-05:
      DOI: 10.1002/ps.4465
       
  • Mesoionic insecticides: a novel class of insecticides that modulate
           nicotinic acetylcholine receptors
    • Authors: Caleb W Holyoke; Daniel Cordova, Wenming Zhang, James D Barry, Robert M Leighty, Robert F Dietrich, James J Rauh, Thomas F Pahutski, George P Lahm, My-Hanh Thi Tong, Eric A Benner, John L Andreassi, Rejane M Smith, Daniel R Vincent, Laurie A Christianson, Luis A Teixeira, Vineet Singh, Kenneth A Hughes
      Pages: 796 - 806
      Abstract: BACKGROUNDAs the world population grows towards 9 billion by 2050, it is projected that food production will need to increase by 60%. A critical part of this growth includes the safe and effective use of insecticides to reduce the estimated 20–49% loss of global crop yields owing to pests. The development of new insecticides will help to sustain this protection and overcome insecticide resistance.RESULTSA novel class of mesoionic compounds has been discovered, with exceptional insecticidal activity on a range of Hemiptera and Lepidoptera. These compounds bind to the orthosteric site of the nicotinic acetylcholine receptor and result in a highly potent inhibitory action at the receptor with minimal agonism. The synthesis, biological activity, optimization and mode of action will be discussed.CONCLUSIONTriflumezopyrim insect control will provide a powerful tool for control of hopper species in rice throughout Asia. Dicloromezotiaz can provide a useful control tool for lepidopteran pests, with an underexploited mode of action among these pests. © 2016 Society of Chemical Industry
      PubDate: 2017-02-01T05:21:02.220463-05:
      DOI: 10.1002/ps.4496
       
  • A retrospective look at anthranilic diamide insecticides: discovery and
           lead optimization to chlorantraniliprole and cyantraniliprole
    • Authors: Thomas P Selby; George P Lahm, Thomas M Stevenson
      Pages: 658 - 665
      Abstract: Anthranilic diamides are an important commercial synthetic class of insecticides (IRAC Group 28) that bind to the ryanodine receptor with selective potency against insect versus mammalian forms of the receptor. The first commercialized diamide, chlorantraniliprole, has exceptional activity against lepidopteran pests. The second anthranilamide product, cyantraniliprole, has excellent cross-spectrum activity against a range of insect orders, including both lepidopteran and hemipteran pests. Here, a retrospective look is presented on the discovery of the class, along with chemistry highlights of the lead evolution to both products. © 2016 Society of Chemical Industry
      PubDate: 2016-06-07T02:15:34.725034-05:
      DOI: 10.1002/ps.4308
       
  • It takes a team: reflections on insecticide discoveries, toxicological
           problems and enjoying the unexpected
    • Authors: Keith D Wing
      Pages: 666 - 671
      Abstract: Absorption/distribution/metabolism/excretion (ADME)-related studies are mandatory in agrochemical development/registration, but can also play a valuable role in the discovery process. In combination with target-site potency, bioavailability/ADME characteristics determine agrochemical bioactivity and selectivity, and these concerns can dictate the fate of a discovery lead area. Bioavailability/ADME research was critical to the eventual commercialization of three different insecticide chemistries examined in this paper. In one situation, improved systemicity in anthranilic diamides was required to expand pest spectrum. In another, ADME tools were needed to improve the selective toxicity and non-target safety of sodium channel blocker insecticides. Finally, differential ADME characteristics of two classes of hormone agonists dictated differential insecticidal activity, and were useful in optimizing the dibenzoylhydrazine ecdysone agonists. ADME discovery research will help companies to advance novel, efficacious and selective agrochemicals, but organizational patience and a desire to understand lead areas in depth are required. © 2016 Society of Chemical Industry
      PubDate: 2016-06-06T02:20:25.249155-05:
      DOI: 10.1002/ps.4311
       
  • Perspectives on the agrochemical industry and agrochemical discovery
    • Authors: Thomas C Sparks; Beth A Lorsbach
      Pages: 672 - 677
      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 spectra, and changing agricultural needs and practices. As presented in the associated analysis of the agrochemical industry, the rising costs and complexities of agrochemical discovery have, in part, led to increasing consolidation, especially in the USA and Europe. However, as demonstrated by the present analysis, the discovery of new agrochemicals continues in spite of the challenges. © 2016 Society of Chemical Industry
      PubDate: 2016-12-16T08:40:28.461041-05:
      DOI: 10.1002/ps.4457
       
  • 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
      Pages: 678 - 685
      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 necessitates 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 have 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. © 2016 Society of Chemical Industry
      PubDate: 2016-08-12T21:20:33.896369-05:
      DOI: 10.1002/ps.4336
       
  • Delivery strategies: RNA interference in agriculture and human health
    • Authors: Richard W Heidebrecht
      Pages: 686 - 691
      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? © 2016 Society of Chemical Industry
      PubDate: 2016-08-10T03:30:52.541071-05:
      DOI: 10.1002/ps.4341
       
  • Insecticide ADME for support of early-phase discovery: combining classical
           and modern techniques
    • Authors: Michael D David
      Pages: 692 - 699
      Abstract: The two factors that 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 that 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. © 2016 Society of Chemical Industry
      PubDate: 2016-08-19T00:30:28.927525-05:
      DOI: 10.1002/ps.4345
       
  • Natural products, their derivatives, mimics and synthetic equivalents:
           role in agrochemical discovery
    • Authors: Thomas C Sparks; Donald R Hahn, Negar V Garizi
      Pages: 700 - 715
      Abstract: Natural products (NPs) have a long history as a source of, and inspiration for, novel agrochemicals. Many of the existing herbicides, fungicides, and insecticides have their origins in a wide range of NPs from a variety of sources. Owing 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. Although 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 the 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. © 2016 Society of Chemical Industry
      PubDate: 2016-12-17T12:05:28.618395-05:
      DOI: 10.1002/ps.4458
       
  • Evolution of resistance to pyrethroid insecticides in Musca domestica
    • Authors: Jeffrey G Scott
      Pages: 716 - 722
      Abstract: Houseflies, Musca domestica L., are a significant pest because of the numerous diseases they transmit. Control of housefly 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). Houseflies have evolved resistance to pyrethroids owing 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 multihalogenated benzyl pyrethroids, for which super-kdr confers less resistance than kdr. P450-mediated resistance can result from overexpression of CYP6D1 or another P450 (unidentified) whose overexpression is linked to autosomes II or V. The initial use of field-stable pyrethroids resulted in different patterns of evolution across the globe, but with time these mutations have become more widespread in their distribution. What is known about the fitness costs of the resistance alleles in the absence of insecticide is discussed, particularly with respect to the current and future utility of pyrethroid insecticides. © 2016 Society of Chemical Industry
      PubDate: 2016-07-13T05:09:12.334979-05:
      DOI: 10.1002/ps.4328
       
  • 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
      Pages: 731 - 742
      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 whether these changes would improve potency.RESULTSStructure–activity relationship (SAR) studies showed that, with respect to the methylene linker, both mono- and disubstitution 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.CONCLUSIONA novel series of compounds exploring 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 at the terminal tail with bulkier substituents. A quantitative structure–activity relationship 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 to explain the observed activity with the various substituents. © 2016 Society of Chemical Industry
      PubDate: 2016-09-07T07:25:35.584583-05:
      DOI: 10.1002/ps.4351
       
  • Insecticidal activity of novel thioureas and isothioureas
    • Authors: William T Lambert; Miriam E Goldsmith, Thomas C Sparks
      Pages: 743 - 751
      Abstract: BACKGROUNDWe hypothesized that the 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 that 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. © 2016 Society of Chemical Industry
      PubDate: 2016-09-09T05:31:18.629895-05:
      DOI: 10.1002/ps.4353
       
  • 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
      Pages: 752 - 760
      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 owing to a possible vacuole-trapping mechanism. Physical property modulation via a prodrug approach was attempted to overcome this mechanism.RESULTSClonidine showed insecticidal activity against M. persicae and B. tabaci. A prodrug of a known open-chain analog of clonidine was developed. While the prodrug had decreased pKa and increased lipophilicity and displayed good activity against M. persicae B. tabaci, the activity did not translate to cotton. Metabolic studies showed that the prodrug 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 prodrug approach did not overcome the lack of translation in this case. Studies confirmed that the synthesized prodrug analog metabolized in planta to the 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. © 2016 Society of Chemical Industry
      PubDate: 2016-08-25T06:25:26.031115-05:
      DOI: 10.1002/ps.4358
       
  • Synthesis and biological activity of a new class of insecticides: the
           N-(5-aryl-1,3,4-thiadiazol-2-yl)amides
    • Authors: Joseph D Eckelbarger; Marshall H Parker, Maurice CH Yap, Ann M Buysse, Jonathan M Babcock, Ricky Hunter, Yelena Adelfinskaya, Jack G Samaritoni, Negar Garizi, Tony K Trullinger
      Pages: 761 - 773
      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 a 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).CONCLUSIONStructure–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. © 2016 Society of Chemical Industry
      PubDate: 2016-08-30T00:40:29.16551-05:0
      DOI: 10.1002/ps.4359
       
  • Discovery of the aryl heterocyclic amine 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
      Pages: 774 - 781
      Abstract: BACKGROUNDγ-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 (AHAs) 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 2–4 times lower than commercial standards and also appeared to be species dependent, with good activity seen for larvae of Spodoptera exigua, but inactivity 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. © 2016 Society of Chemical Industry
      PubDate: 2016-10-26T01:55:38.652286-05:
      DOI: 10.1002/ps.4431
       
 
 
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