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Journal Cover Pest Management Science
  [SJR: 1.262]   [H-I: 72]   [4 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1526-498X - ISSN (Online) 1526-4998
   Published by John Wiley and Sons Homepage  [1598 journals]
  • Intermediate derivatization method in the discovery of new acaricide
           candidate: synthesis of N‐substituted piperazines derivatives and
           their activity against phytophagous mites
    • Authors: Yong Xie; Ying Xu, Changling Liu, Aiying Guan, Lanfeng Ban, Fei Ding, Wei Peng
      Abstract: BACKGROUND To discover and exploit novel acaricidal compounds, a series of novel N‐substituted piperazines derivatives were designed and synthesized using a tert‐butyl piperazine‐1‐carboxylate as starting material by intermediate derivatization methods and their acaricidal activities were evaluated. RESULTS The acaricidal activity showed compounds 11 and 12 exhibited significant acaricidal activity against adults of Tetranychus cinnabarinus in greenhouse tests. Compound 12 in particular was found to be the best potential candidate acaricide and proved more active than that of the commercial positive controls spirodiclofen and pyridaben, with an LC50 of 0.8977 mg L−1. The results of acaricidal activities against larvae and eggs of Tetranychus cinnabarinus indicated that compound 12 possessed equivalent larvicidal activity to spirodiclofen and higher larvicidal activity than pyridaben. Meanwhile, compound 12 showed less ovicidal activity than pyridaben, but higher activity than spirodiclofen. Furthermore, the results of the field trial demonstrated that compound 12 could effectively control Panonychus citri and Panonychus ulmi with long‐lasting persistence and rapid‐acting property. CONCLUSIONS The present work indicates that compound 12 could be a novel acaricide candidate for spider mites control.
      PubDate: 2016-07-23T03:15:32.568748-05:
      DOI: 10.1002/ps.4369
  • Synthesis and Insecticidal Activity of Novel Pyrimidine Derivatives
           Containing Urea pharmacophore against Aedes aegypti
    • Abstract: BACKGROUND Aedes aegypti is a major mosquito vector for the transmission of serious diseases, especially dengue and yellow fever. More than one billion people in developing countries are at risk. The widespread and continual use of pesticides can lead to resistant mosquitoes. In order to maintain mosquito control gains, it is critical to develop and evaluate novel bioactive molecules that differ in mode of action from currently used products. RESULTS A series of novel pyrimidine derivatives were designed and synthesized. Their structures were elucidated by 1H NMR and HRMS. Biological activities of these compounds were tested against Aedes aegypti. Many of them exhibited insecticidal activity against adult and larval mosquitoes. Compound 4d displayed relatively good activity to reach 70% mortality at 2 µg/mL. Furthermore, DFT (Density functional theory) calculations were established to study the structure‐activity relationship of these novel compounds. CONCLUSION A practical synthetic route for pyrimidine derivatives is presented. This study suggests that these pyrimidine derivatives exhibited some activity against the yellow fever mosquito, and with further structure modification, could be novel lead compounds for the development of insecticides against mosquitoes.
      PubDate: 2016-07-23T03:15:26.888181-05:
      DOI: 10.1002/ps.4370
  • Efficacy of tebuconazole embedded in biodegradable
           poly‐3‐hydroxybutyrate to inhibit the development of Fusarium
           moniliforme in soil microecosystems
    • Abstract: Background An important line of research is the development of a new generation of formulations with targeted and controlled release of the pesticide, using matrices made from biodegradable materials. In this study, slow‐release formulations of the fungicide tebuconazole (TEB) have been prepared by embedding it into the matrix of poly‐3‐hydroxybutyrate (P3HB) in the form of films, microgranules, and pellets. Results The average rates of P3HB degradation rates were determined by the geometry of the formulation, reaching for 63 days 0.095‐0.116; 0.081‐0.083; 0.030‐0.055 mg d−1 for films, microgranules, and pellets, respectively. The fungicidal activity of P3HB/TEB against the plant pathogen Fusarium moniliforme was compared with that of the commercial formulation Raxil Ultra. A pronounced fungicidal effect of the experimental P3HB/TEB formulations was observed in 2–4 weeks after application, and it was retained for 8 weeks, without affecting significantly the development of soil aboriginal microflora. Conclusions TEB release can be regulated by the process employed to fabricate the formulation and the fungicide loading and that TEB accumulates in the soil gradually, as the polymer is degraded. The experimental forms of TEB embedded in the slowly degraded P3HB can be used as a basis for developing slow‐release fungicide formulations.
      PubDate: 2016-07-22T09:20:27.285264-05:
      DOI: 10.1002/ps.4367
  • Forward selection for multiple resistance across the non‐selective
    • Abstract: BACKGROUND In the Mediterranean area, Lolium species have evolved resistance to glyphosate after decades of continue use without other alternative chemicals in perennial crops (olive, citrus and vineyard). In recent years, oxyfluorfen alone or mixed with glyphosate and glufosinate have been introduced as chemical options to control dicot and grass weeds. RESULTS Dose response studies confirmed that three glyphosate resistant Lolium weed species (L. rigidum, L. perenne, L. multiflorum) collected from perennial crops in the Iberian Peninsula have also evolved resistance to glufosinate and oxyfluorfen herbicides, despite their recent introduction. Based on LD50 resistance parameter, resistance factor was similar among Lolium species and ranged from 14‐21‐fold and 10‐12‐fold for oxyfluorfen and glufosinate, respectively. Similarly, about 14‐fold resistance to both oxyfluorfen and glufosinate was estimated in average for the three Lolium species when growth reduction (GR50) was assessed. This study identified oxyfluorfen resistance in a grass species for the first time. CONCLUSION A major threat to sustainability of perennial crops in the Iberian Peninsula is evident as multiple resistance to non‐selective glyphosate, glufosinate and oxyfluorfen herbicides has evolved in L. rigidum, L. perenne and L. multiflorum weeds.
      PubDate: 2016-07-22T09:20:24.457363-05:
      DOI: 10.1002/ps.4368
  • Susceptibility of Selected Boreal Fruits and Berries to the Invasive Pest
           Drosophila suzukii (Diptera: Drosophilidae)
    • Authors: Catherine M Little; Thomas W Chapman, Debra L Moreau, N Kirk Hillier
      Abstract: BACKGROUND Drosophila suzukii Matsumara has recently emerged as a major invasive pest species in soft‐skinned fruits in berries throughout N. America and Europe. Its distribution has spread so rapidly that little is known of the extent of fruit susceptibility, particularly in boreal regions. Populations of D. suzukii increase dramatically in late summer in boreal regions, concurrent with fruiting seasons for commercially and culturally significant fruits and berries. We tested fruit preference and susceptibility of lingonberry, blueberry, chokecherry, sea buckthorn, and raspberry fruits to D. suzukii. RESULTS Female D. suzukii attempted to oviposit on all fruit types tested. Fruits with lower brix and lower pH levels were preferred in choice tests. Undamaged lingonberries were relatively safe from infestation; however, bruised or frost‐damaged fruits were easily penetrated. Sea buckthorn and raspberry fruits were highly preferred. CONCLUSIONS Although blueberry growers have experienced severe economic crop losses due to D. suzukii, we have found that blueberries were the least preferred of fruits tested. This suggests that D. suzukii are largely opportunistic and highlights the importance of fruit phenology in fruit susceptibility.
      PubDate: 2016-07-22T09:15:59.719798-05:
      DOI: 10.1002/ps.4366
  • Systemic RNAi in the small hive beetle (Aethina tumida Murray, Coleoptera:
           Nitidulidae), a serious pest of the European honey bee (Apis mellifera)
    • Authors: Michelle E. Powell; Hannah M. Bradish, John A. Gatehouse, Elaine C. Fitches
      Abstract: BACKGROUND Aethina tumida is a serious pest of the European honey bee (Apis mellifera) in North America and Australia. Here we investigate whether Laccase 2, phenoloxidase gene essential for cuticle sclerotization and pigmentation in many insects, and vacuolar‐ATPase V‐type subunit A, vital for the generation of proton gradients used to drive a range of transport processes, could be potential targets for RNAi‐mediated control of A. tumida. RESULTS Injection of V‐ATPase subunit A (5 ng) and Laccase 2 (12.5 ng) dsRNAs resulted in 100 % larval mortality, qPCR confirmed significant decreases and enhanced suppression of transcript levels over time. Oral delivery of V‐ATPase subunit A dsRNA in solutions resulted in 50 % mortality, however gene suppression could not be verified. We suggest that the inconsistent RNAi effect was a consequence of dsRNA degradation within the gut due to the presence of extracellular nucleases. Target specificity was confirmed by a lack of effect on survival or gene expression in honey bees injected with A. tumida dsRNAs. CONCLUSIONS This is the first study to show evidence for systemic RNAi in A. tumida in response to injected dsRNA but further research is required to develop methods to induce RNAi effects via ingestion.
      PubDate: 2016-07-22T09:10:32.046249-05:
      DOI: 10.1002/ps.4365
  • Recurrent selection with reduced 2,4‐D amine doses results in the
           rapid evolution of 2,4‐D herbicide resistance in wild radish
           (Raphanus raphanistrum L.)
    • Authors: Michael B. Ashworth; Michael J. Walsh, Ken C. Flower, Stephen B. Powles
      Abstract: BACKGROUND When used at effective doses, weed resistance to auxinic herbicides has been slow to evolve when compared to other modes of action. Here we report the evolutionary response of a herbicide‐susceptible population of wild radish (Raphanus raphanistrum L.) and confirm that sub‐lethal doses of 2,4‐D amine can lead to the rapid evolution of 2,4‐D resistance and cross resistance to acetolactate synthase (ALS) inhibiting herbicides. RESULTS Following four generations of 2,4‐D selection, the progeny of a herbicide‐susceptible wild radish population evolved 2,4‐D resistance, increasing the LD50 from 16 g ha−1 to 138 g ha−1. Along with 2,4‐D resistance, cross resistance to the ALS‐inhibiting herbicides metosulam (4.0‐fold), and chlorsulfuron (4.5‐fold) was evident. Pre‐treatment of the 2,4‐D‐selected population with the cytochrome P450 inhibitor, malathion, restored chlorsulfuron to full efficacy, indicating that cross resistance to chlorsulfuron was likely due to P450 catalysed enhanced rates of herbicide metabolism. CONCLUSION This study is the first to confirm the rapid evolution of auxinic herbicide resistance through the use of low doses of 2,4‐D and serves as a reminder that 2,4‐D must always be used at highly effective doses. With the introduction of transgenic auxinic herbicide resistant crops in the America's there will be a marked increase in auxinic herbicide use and therefore the risk of resistance evolution. Auxinic herbicides should be used only at effective doses and with diversity if resistance is to remain a minimal issue.
      PubDate: 2016-07-21T11:50:26.311405-05:
      DOI: 10.1002/ps.4364
  • Costs and benefits of insecticide and foliar nutrient applications to
           HLB‐infected citrus trees
    • Authors: James A. Tansey; Pilar Vanaclocha, Cesar Monzo, Moneen Jones, Philip A. Stansly
      Abstract: BACKGROUND The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae), vectors ‘Candidatus Liberibacter asiaticus’ that causes huanglongbing (HLB). In Florida, HLB incidence is approaching 100% statewide. Yields have decreased and production costs have increased since 2005. Despite this, some growers are maintaining a level of production and attribute this in part to aggressive psyllid control and foliar nutrition sprays. However, the value of these practices is debated. A replicated field study was initiated in 2008 in a commercial block of ‘Valencia’ sweet orange trees to evaluate individual and combined effects of foliar nutrition and ACP control. Results from 2012–2016 are presented. RESULTS Insecticides consistently reduced ACP populations. However, neither insecticide nor nutrition applications significantly influenced HLB incidence nor PCR copy number in mature trees. In reset trees, infection continued to build and reached 100% in all treatments. Greatest yields (kg fruit/ ha) and production (kg s/ ha) were obtained from trees receiving both insecticides and foliar nutrition. CONCLUSIONS All treatments resulted in production and financial gains relative to controls. However, material and application costs associated with the nutrition component offset these gains resulting in lesser benefits than insecticides applied alone.
      PubDate: 2016-07-18T05:53:45.896665-05:
      DOI: 10.1002/ps.4362
  • Structure‐based bioisosterism design, synthesis, insecticidal
           activity and structure‐activity relationship (SAR) of anthranilic
           diamides analogs containing 1,2,4‐oxadiazole rings
    • Abstract: BACKGROUND Anthranilic diamides derivatives are among the most important classes of synthetic insecticides. Besides the 1,2,4‐oxadiazole heterocycle, a bioisostere of amide, has been extensively used in pesticide. In order to discover novel molecules with high insecticidal activities, a series of anthranilic diamides analogs containing 1,2,4‐oxadiazole rings were designed and synthesized. RESULTS A series of novel anthranilic diamides derivatives containing 1,2,4‐oxadiazole were obtained, and confirmed by 1H NMR, 13C NMR and HRMS. The structure of 3‐bromo‐N‐(4‐chloro‐2‐methyl‐6‐(3‐((methylsulfonyl)methyl)‐1,2,4‐oxadiazol‐5‐yl)phenyl)‐1‐(3‐chloropyridin‐2‐yl)‐1H‐pyrazole‐5‐carboxamide was further characterized by X‐ray diffraction analysis. In addition, bioassays showed that most of the newly synthesized compounds displayed 100 % mortality against Plutella xylostella at 100 mg L−1. And compound 3IIl showed 90 % larvicidal activities at the concentration of 0.5 mg L−1. The LC50 value of 3IIl was 0.20 mg L−1, which indicated that it may be used as potential leading compound for further structural optimization. Furthermore, a brief comparative molecular field analysis models were established to study the structure‐activity relationship of the title compounds. CONCLUSION Compound 3IIl may be used as potential leading compound for further structural optimization. And the SAR and CoMFA model could provide reliable clues for further structural optimization.
      PubDate: 2016-07-18T05:53:44.735627-05:
      DOI: 10.1002/ps.4363
  • Homozygous and heterozygous point mutations in succinate dehydrogenase
           subunits b, c, and d of Rhizoctonia cerealis conferring resistance to
    • Abstract: BACKGROUND Thifluzamide, a succinate dehydrogenase inhibitor (SDHI) fungicide, is a promising fungicide for controlling wheat sharp eyespot (WSE). WSE is caused by Rhizoctonia cerealis. Information on the resistance mechanism of this pathogen to thifluzamide remains unavailable. RESULTS We used selective re‐culturing and UV mutagenesis to generate thifluzamide resistant mutants. Thifluzamide‐resistant mutants were only generated through UV mutagenesis. Sequence analysis of succinate dehydrogenase (Sdh) genes revealed that two mutants had no mutation in RCSdhB, RCSdhC, and RCSdhD and the other 18 mutants all had at least a one mutation in RCSdhB, RCSdhC, or RCSdhD, either in a homozygous or heterozygous state. The majority of mutants included either RCSdhD‐H116Y or RCSdhC‐H139Y. They showed slight resistance to boscalid, bixafen, and penflufen. Only one mutant possessed RCSdhB‐H246Y and it showed medium resistance to boscalid, penflufen, and a slight resistance to bixafen. All the thifluzamide mutants were sensitive to flutolanil. Compared with their parental isolates, these mutants present no or minor fitness penalties. CONCLUSION Homozygous and heterozygous point mutations in the succinate dehydrogenase subunits b, c, and d of R. cerealis may be involved in thifluzamide resistance.
      PubDate: 2016-07-14T09:06:00.392682-05:
      DOI: 10.1002/ps.4361
  • Synthesis and Biological Activity of a New Class of Insecticides: the
    • Authors: Joseph D. Eckelbarger; Marshall H. Parker, Maurice C. H. Yap, Ann M. Buysse, Jonathan M. Babcock, Ricky Hunter, Yelena Adelfinskaya, Jack G. Samaritoni, Negar Garizi, Tony K. Trullinger
      Abstract: BACKGROUND Optimization studies on a high throughput screening (HTS) hit led to the discovery of a series of N‐(6‐arylpyridazin‐3‐yl)amides with insecticidal activity. It was hypothesized that the isosteric replacement of the pyridazine ring with a 1,3,4‐thiadiazole ring could lead to more potent biological activity and/or broader sap‐feeding pest spectrum. The resulting N‐(5‐aryl‐1,3,4‐thiadiazol‐2‐yl)amides were explored as a new class of insecticides. RESULTS Several methods for 2‐amino‐1,3,4‐thiadiazole synthesis were used for the preparation of key synthetic intermediates. Subsequent coupling to variously substituted carboxylic acid building blocks furnished the final targets, which were tested for insecticidal activity against susceptible strains of Aphis gossypii (Glover) (cotton aphid), Myzus persicae (Sulzer) (green peach aphid), and Bemisia tabaci (Gennadius) (sweetpotato whitefly). CONCLUSIONS Structure‐activity relationship (SAR) studies on both the amide tail and the aryl A‐ring of novel N‐(5‐aryl‐1,3,4‐thiadiazol‐2‐yl)amides led to a new class of insecticidal molecules active against sap‐feeding insect pests.
      PubDate: 2016-07-14T08:55:38.584957-05:
      DOI: 10.1002/ps.4359
  • Pro‐Insecticidal Approach Towards Increasing In Planta Activity
    • Authors: Lawrence C. Creemer; Natalie C. Giampietro, William Lambert, Maurice C. Yap, Gerrit J. deBoer, Yelena Adelfinskaya, Scott Castetter, Frank J. Wessels
      Abstract: BACKGROUND The adrenergic mode of action was investigated for the development of potential new insecticides. Clonidine related analogs were tested against Myzus persicae (Sulzer) and Bemisia tabaci (Gennadius). Clonidine analogs lack translation due to a possible vacuole trapping mechanism. Physical properties modulation via a pro‐drug approach was attempted to overcome this mechanism. RESULTS Clonidine showed insecticidal activity against M. persicae and B. tabaci. A pro‐drug of a known open‐chain analog of clonidine, was developed. While the pro‐drug had decreased pKa and increased lipophillicity and displayed good activity against M. persicae and B. tabaci, the activity did not translate on cotton. Metabolic studies showed the pro‐drug was quickly metabolized to the parent compound, and was further metabolized to a known vacuole‐trapped oxazoline analog. CONCLUSIONS Adrenergic active compounds, such as clonidine analogs, show potential as insecticides; however, a designed pro‐drug approach did not overcome lack of translation in this case. Studies confirmed that the synthesized pro‐drug analog metabolized in planta to a proposed vacuole‐trapped compound. One possible explanation for the failure of this approach is that the rate of metabolism and vacuole trapping is faster than translaminar flow and therefore the released pesticide is not biologically available to the target organism.
      PubDate: 2016-07-14T08:55:27.754405-05:
      DOI: 10.1002/ps.4358
  • Effects of trans‐2‐Hexenal on Reproduction, Growth and
           Behavior and Efficacy against Pinewood Nematode, Bursaphelenchus
    • Authors: Le Cheng; Shuangyu Xu, Chunmei Xu, Hongbao Lu, Zhengqun Zhang, Daxia Zhang, Wei Mu, Feng Liu
      Abstract: BACKGROUND Bursaphelenchus xylophilus is a serious quarantined pest that causes severe damage and major economic losses to pine forests. Because of the adverse effects of some traditional nematicides on human and the environment, new plant toxicants against these nematodes have intensified. Nematicidal activity of trans‐2‐hexenal, which is a six carbon aldehyde present in many plants, was tested against the nematode. RESULTS trans‐2‐Hexenal showed significant efficacy against B. xylophilus at a dose range of 349.5‐699 g m‐3 by fumigation of pine wood logs. Additionally, it had significant nematicidal activity against different life stages of B. xylophilus in‐vitro test, with second‐stage larvae (L2s) being the most sensitive, which had LC50 value of 9.87 µg mL‐1 at 48 h. Egg hatch was also significantly inhibited. Further studies revealed that trans‐2‐hexenal inhibited the reproductive activity of B. xylophilus, with negative effects on reproduction rate and egg numbers. Moreover, trans‐2‐hexenal reduced the body length of B. xylophilus. Respiratory rate and thrashing behavior of B. xylophilus also decreased following treatment with this compound. CONCLUSION trans‐2‐hexenal had significant nematicidal activity against B. xylophilus, providing a basis for elucidation of the mode of action of trans‐2‐hexenal against plant parasitic nematodes in future studies.
      PubDate: 2016-07-14T08:55:25.229031-05:
      DOI: 10.1002/ps.4360
  • Effect of plant resistance and BioAct WG (Purpureocillium lilacinum strain
           251) on Meloidogyne incognita in a tomato–cucumber rotation in a
    • Abstract: BACKGROUND The effectiveness of combining resistant tomato with BioAct WG (Purpureocillium lilacinum strain 251; Pl251) against Meloidogyne incognita was assessed in a tomato‐cucumber rotation in greenhouse over two years. Additionally, the enzymatic activity of the fungus, the percentage of fungal egg and juvenile parasitism, cardinal temperatures and the effect of water potential on mycelial growth and the soil receptivity to Pl251 were determined in vitro. RESULTS Plant resistance was the only factor that suppressed nematode and crop yield losses. Percentage of egg parasitism in plots treated with BioAct WG was less than 2.6 %. However under in vitro conditions, Pl251 showed protease, lipase, and chitinase activities, and parasitized 94.5 % of eggs, but no juveniles. Cardinal temperatures were 14.2, 24‐26, and 35.4 °C. The maximum Pl251 mycelial growth was at ‐0.25 MPa and 25 °C. Soil temperatures and water potential in the greenhouse were in the range of the fungus. However, soil receptivity was less in greenhouse soil, irrespective of sterilization, than in sterilized sand. CONCLUSIONS Plant resistance was the only factor able to suppress nematode densities, disease severity and yield losses, and to protect the following cucumber crop. Environmental factors involved in soil receptivity could have negatively affected fungus effectiveness.
      PubDate: 2016-07-14T08:55:23.174418-05:
      DOI: 10.1002/ps.4357
  • Effects of Residual Novaluron on Reproduction in Alfalfa Leafcutting Bees,
           Megachile rotundata F. (Megachilidae)
    • Abstract: Background The chitin synthesis inhibitor novaluron can suppress pests that affect alfalfa seed production, but can negatively impact reproductive success in the alfalfa pollinator Megachile rotundata. Novaluron is considered a reduced risk insecticide because it disrupts ecdysis and is nonlethal to adults, but some exposed adult insects have fewer eggs and suppressed egg hatch. For this experiment, bees nested in field cages where they were exposed to alfalfa never treated with novaluron, alfalfa that was recently sprayed, or alfalfa that had been sprayed one and two weeks earlier. Results Compared to control, greater proportions of dead eggs and larvae and lower proportions of live prepupae occurred when bees were exposed to recent novaluron sprays as well as one‐ or two‐week old spray residues. Two possible routes of residual pesticide exposure were revealed. Mother bees become contaminated through ingestion or direct contact. Or, pollen‐nectar provisions become contaminated with novaluron 1) on or within leaf pieces that surround provisions or 2) transferred from mother bees’ bodies to provisions. Conclusion We found strong immature mortality effects of novaluron and its residues on M. rotundata. Understanding all possible pesticide exposure routes for pollinating bees enhances decision‐making for maintaining bee populations while protecting crops.
      PubDate: 2016-07-12T09:25:19.625365-05:
      DOI: 10.1002/ps.4356
  • Sorption and desorption characteristics of methyl bromide during and after
           fumigation of pine (Pinus radiata D. Don) logs
    • Abstract: BACKGROUND The sorption and desorption characteristics of methyl bromide (MB) were determined during and after fumigation of recently harvested pine (Pinus radiata D. Don) logs. The effects of dose (48 or 120 g m−3), degree of bark cover (0, 50 or 100%) and end‐grain sealing (sealed or unsealed) on sorption and desorption were determined over time. RESULTS Sorption of MB was proportional to the dose applied and dependent on the amount of end‐grain sealed. After 16 h, an average of 70.7 ± 2.5% of the initial concentration remained in the treated space when end‐grains were sealed whereas only 47.3 ± 2.5% remained when unsealed. During aeration, MB was released from logs initially ranging from 2.8 to 8.8 g.h m−3, depending on the treatment. The rate of desorption quickly decreased during aeration. CONCLUSION The surface area of a log is the most important factor influencing MB sorption and desorption rates, with greater surface area resulting in a greater (de)sorption rates. Sorption data can now be combined with insect toxicity data to estimate a minimum effective dose of MB for further evaluation; while desorption data can be combined with fumigant plume modelling to assess worker safety.
      PubDate: 2016-07-12T09:16:04.038919-05:
      DOI: 10.1002/ps.4355
  • Insecticidal Activity of Novel Thioureas and Isothioureas
    • Authors: William T. Lambert; Miriam E. Goldsmith, Thomas C. Sparks
      Abstract: BACKGROUND We hypothesized that exploration of chemical space around compounds with reported insecticidal activity could be a viable strategy for discovering novel, insecticidally active areas of chemistry. RESULTS A series of thioureas and isothioureas were prepared as part of a scaffold‐hopping effort around known insecticidal compounds. Many of these compounds showed excellent activity against key sap‐feeding insect pests in insecticidal bioassays. While analogs bearing monocyclic thiophene head groups showed activity against Myzus persicae (green peach aphid), analogs with diarylethane head groups were active against both M. persicae and Bemisia tabaci (sweetpotato whitefly). Despite compelling activity in these laboratory tests, these compounds showed diminished activity when applied to host plants via tracksprayer. CONCLUSIONS The initial hypothesis that structural modification of molecules reported to have insecticidal activity would yield novel compounds which also exhibit insecticidal activity was validated. Despite excellent activity in laboratory bioassays, these new compounds failed to show compelling activity in more demanding tracksprayer tests.
      PubDate: 2016-07-08T08:35:25.173009-05:
      DOI: 10.1002/ps.4353
  • Weed seed inactivation in soil mesocosms via biosolarization with mature
           compost and tomato processing waste amendments
    • Abstract: BACKGROUND Biosolarization is a fumigation alternative that combines passive solar heating with amendment‐driven soil microbial activity to temporarily create antagonistic soil conditions, such as elevated temperature and acidity, that can inactivate weed seeds and other pest propagules. The aim of this study was to use a mesocosm‐based field trial to assess soil heating, pH, volatile fatty acid accumulation, and weed seed inactivation during biosolarization. RESULTS Biosolarization for 8 days using 2% mature green waste compost and 2 or 5% tomato processing residues in the soil resulted in accumulation of volatile fatty acids in the soil, particularly acetic acid, and >95% inactivation of Brassica nigra and Solanum nigrum seeds. Inactivation kinetics data showed that near complete weed seed inactivation in soil was achieved within the first 5 days of biosolarization. This was significantly greater than the inactivation achieved in control soils that were solar heated without amendment or were amended but not solar heated. CONCLUSION The composition and concentration of organic matter amendments in soil significantly affected volatile fatty acid accumulation at various soil depths during biosolarization. Combining solar heating with organic matter amendment resulted in accelerated weed seed inactivation compared to either approach alone.
      PubDate: 2016-07-08T08:35:21.04782-05:0
      DOI: 10.1002/ps.4354
  • Eradicating grey squirrel Sciurus carolinensis from urban areas: an
           innovative decision making approach based on lessons learnt in Italy
    • Authors: Daniele Paoloni; Valentina La Morgia
      Abstract: BACKGROUND Eradication of Invasive Alien Species supports the recovery of native biodiversity. In Europe, a new Regulation introduces obligations to eradicate the most harmful invasive species. However, eradications of charismatic mammals may encounter strong oppositions. Considering the case study of the Eastern grey squirrel (Sciurus carolinensis Gmelin, 1788) in central Italy, we developed a structured decision making technique, based on a Bayesian Decision Network model and explicitly considering the plurality of environmental values of invasive species management to reduce potential social conflicts. RESULTS The model identified priority areas for management activities. These areas corresponded to the core of the grey squirrel range, but they also included peripheral zones, where rapid eradication is fundamental to prevent the spread of squirrels. However, when the model was expanded also integrating the attitude of citizens towards the project, the intervention strategy slightly changed. In some areas, the citizens’ support was limited and this resulted in a reduced overall utility of intervention. CONCLUSION The suggested approach extends the scientific basis for the management decisions, evaluated in terms of technical efficiency, feasibility and social impact. Here, the Bayesian Decision Network model analysed the potential technical and social consequences of management actions and it responded to the need of transparency in the decision process, but it can be easily extended to consider further issues, common in many mammal eradication programs. Thanks to its flexibility and comprehensiveness, it provides an innovative example of how to plan rapid eradication or control activities, as required by the new EU Regulation.
      PubDate: 2016-07-01T07:40:24.218874-05:
      DOI: 10.1002/ps.4352
  • Toxicity of squamocin on Aedes aegypti larvae, its predators and human
    • Abstract: BACKGROUND The mosquito Aedes aegypti transmit virus that cause diverse human diseases and the vector control is an important strategy to avoid their propagation. Plants in Annonaceae are recognized as source to molecules with use in medical and agriculture fields. Molecules of secondary metabolites of Annonaceae plants exhibit insecticidal potential against insect pest and vectors, with highlight to acetogenins that show high toxicity with low doses, which encouraged research to producing new insecticide molecules. Herein, we identify an acetogenin from Annona mucosa seeds (chemical analysis) and provide toxicity test against larvae of A. aegypti (target insect), its predators Culex bigoti and Toxorhynchites theobaldi (non‐target insects) and cytotoxicity to human leukocytes. RESULTS We identify squamocin (C37H66O7) a fatty acid with presence of bis‐tetrahydrofuran ring. In A. aegypti, this compound exhibited behavioral disturb before larval death, high mortality and require low concentrations to LC50 = 0.01 µg/mL and LC90 = 0.11 µg/mL. However, in predators and human leukocytes the squamocin showed non‐effect toxic which indicate selectivity this molecule to non‐target organism. CONCLUSION We identify squamocin from A. mucosa seeds and reported lethal action against A. aegypti and show that it is selective for non‐target insects and has low cytotoxicity on human cell.
      PubDate: 2016-07-01T07:35:40.975195-05:
      DOI: 10.1002/ps.4350
  • Studies toward Understanding the SAR around the Sulfoximine Moiety of the
           Sap‐Feeding Insecticide Sulfoxaflor
    • Authors: Ann M. Buysse; Benjamin M. Nugent, Nick X. Wang, Zoltan Benko, Nneka Breaux, Richard Rogers, Yuanming Zhu
      Abstract: BACKGROUND The discovery of sulfoxaflor (Isoclast™ active) stemmed from a novel scaffold‐based approach toward identifying bioactive molecules. It exhibits broad spectrum control of many sap‐feeding insect pests, including aphids, whiteflies, hoppers and Lygus. Systematic modifications of the substituents flanking each side of the sulfoximine moiety were carried out to determine if these changes would improve potency. RESULTS Structure activity relationship (SAR) studies showed that with respect to the methylene linker, both mono‐ and di‐substitution with alkyl groups of varying sizes as well as cyclic analogs exhibited excellent control of cotton aphids. However against green peach aphids a decrease in activity was observed with substituents larger than ethyl as well as larger cycloalkyl groups. At the terminal tail there appeared to be a narrow steric tolerance as well, with linear groups or small rings more active against green peach aphids than bulkier groups. CONCLUSIONS A novel series of compounds which explored the substituents flanking the sulfoximine moiety of sulfoxaflor were prepared and tested for bioactivity against cotton aphids and green peach aphids. SAR studies indicated that a decrease in green peach aphid potency was observed at the methylene linker as well as the terminal tail with bulkier substituents. A quantitative structure activity relationship (QSAR) analysis of the compounds revealed significant correlation of activity with two molecular descriptors, vol (volume of a molecule) and GCUT_SMR_3 (molar refractivity). This predictive model helps explain the observed activity with the various substituents.
      PubDate: 2016-07-01T07:35:37.990813-05:
      DOI: 10.1002/ps.4351
  • Unrelenting spread of the alien monk parakeet Myiopsitta monachus in
           Israel. Is it time to sound the alarm?
    • Abstract: BACKGROUND Monk parakeets, Myiopsitta monachus Boddaert are native to South America, but have established populations in North America, Europe, Africa and Asia. They are claimed to act as agricultural pests in their native range, and their communal stick nests may damage human infrastructure. Although several monk parakeet populations are present in the Mediterranean basin and temperate Europe, little empirical data are available on their population size and growth, distribution, and potential impact. We investigated the temporal and spatial dynamics of monk parakeets in Israel to assess their invasion success and potential impact on agriculture. RESULTS Monk parakeet populations are growing exponentially at a higher rate than that reported elsewhere. The current Israeli population of monk parakeets comprises approximately 1500 individuals. The distribution of the species has increased and shifted from predominantly urban areas to agricultural landscapes. CONCLUSIONS In Israel monk parakeet populations are growing fast and have dispersed rapidly from cities to agricultural areas. At present, reports of agricultural damage are scarce. A complete assessment of possible management strategies is urgently needed before the population becomes too large and widespread to allow for cost‐effective mitigation campaigns to be implemented.
      PubDate: 2016-07-01T07:35:32.584788-05:
      DOI: 10.1002/ps.4349
  • Toxicities and effects of insecticidal toxic baits to control Drosophila
           suzukii and Zaprionus indianus (Diptera: Drosophilidae)
    • Authors: Felipe Andreazza; Daniel Bernardi, Cleber A Baronio, Joel Pasinato, Dori E Nava, Marcos Botton
      Abstract: BACKGROUND Drosophila suzukii is a primary insect pest that causes direct damage to fruits with a thin epidermis such as strawberries, cherries, and blueberries. In strawberry fields, the co‐occurrence of D. suzukii and Zaprionus indianus has increased production losses. This study evaluated the toxicities and effects of insecticidal baits to control adults and larvae of both D. suzukii and Z. indianus. RESULTS Organophosphates (dimethoate and malathion), spinosyns (spinosad and spinetoram), pyrethroid (lambda‐cyhalothrin) and diamide (cyantraniliprole) insecticides, exhibited high toxicity to both adults and larvae of D. suzukii and Z. indianus (mortality > 80%) in topical and dip bioassays. However, when the insecticides were mixed with a feeding attractant, a positive effect was observed only for adults of D. suzukii. Insecticides containing neonicotinoids (acetamiprid and thiamethoxam) and pyrolle (chlorfenapyr) caused intermediate mortality to adults of D. suzukii (40% to 60%) and low mortality for Z. indianus (mortality 
      PubDate: 2016-06-29T02:45:21.460099-05:
      DOI: 10.1002/ps.4348
  • Enhancing the Effectiveness of Biological Control Programs of Invasive
           Species through a More Comprehensive Pest Management Approach
    • Authors: Joseph M DiTomaso; Robert A Van Steenwyk, Robert M Nowierski, Jennifer L Vollmer, Eric Lane, Earl Chilton, Patrick L Burch, Phil E. Cowan, Kenneth Zimmerman, Christopher P Dionigi
      Abstract: BACKGROUND Invasive species are one of the greatest economic and ecological threats to agriculture and natural areas in the US and the world. Among the available management tools, biological control provides one of the most economical and long‐term effective strategies for managing widespread and damaging invasive species populations of nearly all taxa. RESULTS Integrating biological control programs in a more complete integrated pest management approach that utilizes increased information and communication, post‐release monitoring, adaptive management practices, long‐term stewardship strategies, and new and innovative ecological and genetic technologies can greatly improve the effectiveness of biological control. In addition, expanding partnerships among relevant national, regional, and local agencies, as well as academic scientists and land managers, offers far greater opportunities for long‐term success in the suppression of established invasive species. CONCLUSIONS In this paper we direct our recommendations to federal agencies that oversee, fund, conduct research, and develop classical biological control programs for invasive species. By incorporating these recommendations into adaptive management strategies, private and public land managers will have far greater opportunities for long‐term success in suppression of established invasive species.
      PubDate: 2016-06-29T02:20:36.694577-05:
      DOI: 10.1002/ps.4347
  • Predation by generalist arthropod predators on Apolygus lucorum
           (Hemiptera: Miridae): molecular gut‐content analysis and
           field‐cage assessment
    • Authors: Jinhua Li; Fan Yang, Qian Wang, Hongsheng Pan, Haibin Yuan, Yanhui Lu
      Abstract: BACKGROUND The mirid bug Apolygus lucorum (Meyer‐Dür) is a principal pest of cotton that also causes great damage to many other crops in China. A study was conducted to assess the mortality of A. lucorum from generalist arthropod predators using both molecular methods and a field‐cage trial. The species‐specific primer pair for the detection of A. lucorum tissues in predators was designed according to the sequences of the cytochrome oxidase subunit I (COI) gene. RESULTS A total of 2096 generalist predators that consisted of ladybeetles, lacewings and spiders were collected, and A. lucorum remains were detected using the designed primers. Only 1.6% of these predators contained A. lucorum DNA, with the highest positive proportion (6.1%) for Harmonia axyridis larvae. In the field‐cage experiment, the daily predation rates of 2nd instar A. lucorum nymphs by H. axyridis adults and larvae were 4.7% and 5.2%, respectively. CONCLUSIONS The overall low positive proportion of generalist predators with A. lucorum DNA detected using the molecular method combined with the low predation rate in the field‐cage experiment indicated that the primary generalist predators likely had a limited role in the suppression of A. lucorum in the field.
      PubDate: 2016-06-28T03:40:20.209566-05:
      DOI: 10.1002/ps.4346
  • Insecticide ADME for Support of Early Phase Discovery: Combining Classical
           and Modern Techniques
    • Authors: Michael D. David
      Abstract: The two factors which determine an insecticide's potency are its binding to a target site (intrinsic activity) and the ability of its active form to reach the target site (bioavailability). Bioavailability is dictated by the compound's stability and transport kinetics, which are determined by both physical and biochemical characteristics. At BASF Global Insecticide Research, we characterize bioavailability in early research with an ADME (Absorption, Distribution, Metabolism, and Excretion) approach, combining classical and modern techniques. For biochemical assessment of metabolism, we purify native insect enzymes using classical techniques, and recombinantly express individual insect enzymes which are known to be relevant in insecticide metabolism and resistance. For analytical characterization of an experimental insecticide and its metabolites, we conduct classical radiotracer translocation studies when a radiolabel is available. In discovery, where typically no radiolabel has been synthesized, we utilize modern high‐resolution mass spectrometry to probe complex systems for the test compounds and its metabolites. By using these combined approaches, we can rapidly compare the ADME properties of sets of new experimental insecticides and aid in the design of structures with an improved potential to advance in the research pipeline.
      PubDate: 2016-06-27T03:45:34.207794-05:
      DOI: 10.1002/ps.4345
  • Potential risk levels of invasive Neoleucinodes elegantalis (small tomato
           borer) in areas optimal for open field Solanum lycopersicum (tomato)
           cultivation in the present and under predicted climate change
    • Abstract: BACKGROUND Neoleucinodes elegantalis is one of the major insect pests of Solanum lycopersicum. Currently N. elegantalis is present only in America and the Caribbean, and is a threat in the world's largest S. lycopersicum producing countries. In terms of potential impact on agriculture, the impact of climate change on insect invasions must be a concern. Currently no research exists regarding the effects of climatic change on risk level of N. elegantalis. The purpose of this study is to develop a model for S. lycopersicum and N. elegantalis utilizing CLIMEX to determine risk levels of N. elegantalis in open field S. lycopersicum cultivation in the present and under projected climate change, using the Global Climate Model, CSIRO‐Mk3.0. RESULTS Large areas are projected to be suitable for N. elegantalis and optimal for open field S. lycopersicum cultivation under current time. However, in the future these areas will become unsuitable for both species. Conversely, in others regions in the future may become optimal for open field S. lycopersicum cultivation with varying risk level for N. elegantalis. CONCLUSION The risk levels results presented here provide a useful tool to design strategies to prevent the introduction and establishment of N. elegantalis in open field S. lycopersicum cultivation.
      PubDate: 2016-06-22T03:30:33.595448-05:
      DOI: 10.1002/ps.4344
  • Impact of volunteer rice infestation on yield and grain quality of rice
    • Authors: Vijay Singh; Nilda R. Burgos, Shilpa Singh, David R. Gealy, Edward E. Gbur, Ana L. Caicedo
      Abstract: BACKGROUND Volunteer rice (Oryza sativa L.) grains may differ in physico‐chemical traits from cultivated rice, which may reduce the quality of harvested rice grain. To evaluate the effect of volunteer rice on cultivated rice, fields were surveyed in Arkansas, USA in 2012. RESULTS Cropping history that included hybrid cultivars in the previous two years (2010 and 2011) had higher volunteer rice infestation (20%) compared to fields planted previously with inbred rice (5.6%). The total grain yield of rice was reduced 0.4% for every 1% increase in volunteer rice density. The grain quality did not change in fields planted with the same cultivar for three years. Volunteer rice density of at least 7.6% negatively impacted the head rice yield. Volunteer rice density of at least 17.7% reduced the rice grain yield. The protein and amylose contents of rice were not affected until volunteer rice infestation exceeded 30%. CONCLUSION Crop rotation systems that include hybrid rice are expected to have higher volunteer rice infestation than systems without hybrid rice. It is predicted that at 8% infestation, volunteer rice will start to impact head rice yield and will reduce total yield at 18% infestation. It could alter the chemical quality of rice grain at >30% infestation.
      PubDate: 2016-06-22T03:30:30.546135-05:
      DOI: 10.1002/ps.4343
  • Behavioral effects of sublethal exposure to a combination of
           β‐cyfluthrin and imidacloprid in the bed bug, Cimex lectularius
    • Authors: Sydney E. Crawley; Katelyn A. Kowles, Jennifer R Gordon, Michael F. Potter, Kenneth F. Haynes
      Abstract: BACKGROUND Bed bugs (Cimex lectularius) are blood‐feeding insect pests with public health relevance. Their rapid evolution of resistance to pyrethroids has prompted a shift to combination products that include both a pyrethroid and neonicotinoid insecticide. Insecticides have both a direct impact on mortality, and an indirect effect on behavior. Thus, we assessed the sublethal effects of a widely used combination product containing β‐cyfluthrin (a pyrethroid) and imidacloprid (a neonicotinoid), since unexpected behavioral changes after exposure have been known to affect efficacy of insecticides. RESULTS We found that bed bugs exposed to sublethal doses of a combination product containing β‐cyfluthrin and imidacloprid did not feed as effectively as untreated bugs. Their locomotion behavior was also reduced. However, aggregation in response to the presence of conspecific harborages was not affected by sublethal exposure. CONCLUSION Bed bugs exhibit behavioral changes after sublethal exposure to a combination product that could affect pest management choices and outcomes. A reduction in host‐finding efficiency and feeding could complement the lethal effects of the insecticide. Alternatively, reduced locomotion following exposure could limit ongoing contact with insecticide deposits. However, an overall reduction in movement indicates that treatments are unlikely to cause dispersal of bugs to adjacent dwellings.
      PubDate: 2016-06-20T09:31:17.433061-05:
      DOI: 10.1002/ps.4342
  • Delivery Strategies: RNA Interference in Agriculture and Human Health
    • Authors: Richard W. Heidebrecht
      Abstract: Crop protection through expression of introduced insecticidal proteins is a well‐established technique. Modifications of endogenous gene expression have also been used successfully to produce safe and effective agrochemical products. The existing gene expression regulatory apparatus can be employed to alter messenger ribonucleic acid (mRNA) stability in the host species through a ribonucleic acid‐interference (RNAi) mechanism. Such solutions are currently delivered by incorporation of new genes into the host plant. Direct delivery of RNAi is being extensively explored in the clinic to treat selected human diseases and could be advantageous in agriculture. What are the unifying characteristics of successful delivery agents, and how can we project those observations into the future?
      PubDate: 2016-06-17T06:11:09.389004-05:
      DOI: 10.1002/ps.4341
  • Expression pattern and pharmacological characterisation of two novel
           alternative splice variants of glutamate‐gated chloride channel in
           the small brown planthopper Laodelphax striatellus
    • Abstract: BACKGROUND Glutamate‐gated chloride channels (GluCl) mediate fast inhibitory neurotransmission in invertebrate nervous systems. Although only one GluCls gene was presented in insects, it showed diverse alternative splicing that was speculated could impact on channel function and pharmacology. RESULTS In this study, we isolated GluCl cDNAs from adult of the small brown planthopper (SBPH, Laodelphax striatellus) and showed that six L. striatellus GluCls variants (LsGluCl‐AS, LsGluCl‐BS, LsGluCl‐CS, LsGluCl‐AL, LsGluCl‐BL and LsGluCl‐CL) were present in the SBPH. The expression patterns of six variants differed among developmental stages (egg, 1st–5th instar nymph, male and female) and among the body parts (head, thorax, abdomen, and leg) of the female adult SBPH. All the transcripts were abundant in the head of the adult. When expressed in Xenopus laevis oocytes, the two functional variants (LsGluCl‐AS and ‐AL) had similar EC50 and IC50 values for L‐glutamate and channel blockers picrotoxinin and fipronil. CONCLUSION This study represents a comprehensive molecular, expression and pharmacological characterisation of GluCl in the SBPH. These findings should be useful in providing more opportunities to discover novel insect control chemicals.
      PubDate: 2016-06-15T03:45:25.801951-05:
      DOI: 10.1002/ps.4340
  • Survey for zoonotic pathogens in Norway rat populations from Europe
    • Abstract: BACKGROUND The Norway rat Rattus norvegicus is an important reservoir of various zoonotic pathogens, such as cowpox virus and Leptospira, but also for agents of no or unknown zoonotic potential. We describe a survey of 426 Norway rats originating from five European countries and different habitats for Leptospira spp., rickettsiae, orthopox virus (OPV), avian metapneumovirus subtype A and B (aMPV), and rat polyomavirus (rat PyV). RESULTS Leptospira DNA was detected in 60 of 420 (14.3%) rats and Rickettsia DNA was found in three of 369 (0.8%) rats investigated. PCR‐based typing resulted in the identification of L. interrogans sequence type 17, serogroup Icterohaemorrhagiae, and Rickettsia helvetica, respectively. Rat PyV DNA was detected in 103 of 421 (24.5%) rats. OPV DNA and aMPV RNA were detected in none of the rats, but OPV‐specific antibodies in three of 388 (0.8%) rats. The frequency of single Leptospira and rat PyV infections and co‐infections was, independent of sex, greater for adults compared to juveniles/subadults and greater at rural sites compared to urban areas. CONCLUSIONS Study results indicate a broad geographical distribution of Leptospira DNA in rats within Europe underlining the need to further investigate potential mechanisms leading to increased prevalence in rural habitats and to assess the relevance to public health. In contrast, rickettsia and OPV infections rarely occurred in wild rat populations. The potential influence of rat PyV on the susceptibility to infections with other pathogens should be investigated in future studies.
      PubDate: 2016-06-14T08:25:32.743798-05:
      DOI: 10.1002/ps.4339
  • A simple approach for a spatial terrestrial exposure assessment of the
           insecticide fenoxycarb based on a high resolution landscape analysis
    • Authors: Kai Thomas; Herbert Resseler, Robert Spatz, Paul Hendley, Paul Sweeney, Martin Urban, Roland Kubiak
      Abstract: BACKGROUND The objective was to refine the standard regulatory exposure scenario used in plant protection product authorisations by developing a more realistic landscape related GIS‐based exposure assessment for terrestrial Non‐Target Arthropods. We quantified the proportion of adjacent off‐target area in agricultural landscapes potentially exposed to insecticide drift from applications of the active substance fenoxycarb. High resolution imagery, landscape classification, and subsequent stepwise analysis of a whole landscape using drift and interception functions were applied to selected areas in representative fruit‐producing regions in Germany. RESULTS Even under worst‐case assumptions regarding treated area, use rate and drift, less than 12 % of the non‐agricultural habitat area would potentially be exposed to fenoxycarb drift above regulatory acceptable concentrations. Additionally, if the filtering effect of tall vegetation were taken into account, this number would decrease to 6.6 %. Further refinements to landscape elements and application conditions indicate that less than 5 % of the habitat area might be exposed above regulatory acceptable concentrations, meaning that 95 % of the non‐agricultural habitat area will be unimpacted (i.e., no unacceptable effects) and can serve as refuge for recolonisation. CONCLUSIONS Approaches and tools are proposed for standardizable and transparent refinements in regulatory risk assessments on landscape level.
      PubDate: 2016-06-14T08:25:28.81018-05:0
      DOI: 10.1002/ps.4338
  • RNAi‐based gene silencing through dsRNA injection or ingestion
           against the African sweetpotato weevil Cylas puncticollis (Coleoptera:
    • Authors: Katterinne Prentice; Olivier Christiaens, Ine Pertry, Ana Bailey, Chuck Niblett, Marc Ghislain, Godelieve Gheysen, Guy Smagghe
      Abstract: BACKGROUND RNA interference (RNAi) technology can potentially serve as a suitable strategy to control the African sweetpotato weevil Cylas puncticollis (SPW), which is a critical pest in Sub‐Saharan Africa. Important prerequisites are required to use RNAi in pest control, such as the presence of an efficient RNAi response and the identification of suitable target genes. RESULTS Here we evaluated the toxicity of dsRNAs targeting essential genes by injection and oral feeding in SPW. In injection assays, 12 of 24 dsRNAs were as toxic as the one targeting Snf7, a gene used commercially against Diabrotica virgifera virgifera. Three dsRNAs with high insecticidal activity were then chosen for oral feeding experiments. The data confirmed that oral delivery can elicit a significant toxicity, albeit lower compared to injection. Subsequently, ex vivo assays revealed that dsRNA is affected by degradation in the SPW digestive system, possibly explaining the lower RNAi effect by oral ingestion. CONCLUSION We conclude that the full potential of RNAi in SPW is affected by the presence of nucleases. Therefore, for future application in crop protection, it is necessary to either constantly provide new dsRNA and/or protect it against possible degradation to obtain a higher RNAi efficacy.
      PubDate: 2016-06-14T08:25:26.11771-05:0
      DOI: 10.1002/ps.4337
  • Lead Generation in Crop Protection Research: A Portfolio Approach to
           Agrochemical Discovery
    • Authors: Michael R. Loso; Negar Garizi, Vidyadhar B. Hegde, James E. Hunter, Thomas C. Sparks
      Abstract: The need for increased food and feed supply to support future global demand with the added challenges of resistance pressure and an evolving regulatory environment necessitate the discovery of new crop protection agents for growers of today and tomorrow. Lead generation is the critical “engine” for maintaining a robust pipeline of new high‐value products. A wide variety of approaches exist for the generation of new leads, many of which having demonstrated success. Each approach features some degree of merit or benefit while also having some inherent drawback or level of risk. While risk for any single approach can be mitigated in a variety of different ways depending on the approach, long‐term viability of a successful lead generation program merits utilization of a portfolio of different approaches and methodologies for the generation of new leads.
      PubDate: 2016-06-14T08:15:39.460503-05:
      DOI: 10.1002/ps.4336
  • Biological control of chestnut blight in Croatia: an interaction between
           host ‐ sweet chestnut, its pathogen Cryphonectria parasitica and the
           biocontrol agent ‐ Cryphonectria hypovirus 1
    • Abstract: BACKGROUND Chestnut blight, caused by the fungus Cryphonectria parasitica, is a severe chestnut disease which can be controlled with naturally occurring hypoviruses in many areas of Europe. The aim of this research was to measure effect of different Cryphonectria hypovirus 1 (CHV1) strains on the growth of fungal host and select strains that could potentially be used for human‐mediated biocontrol in forests and orchards, and to investigate if and how chestnut‐fungus‐virus interactions affect development and growth of lesion area on cut stems. RESULTS Two Croatian CHV1 strains (CR23 and M56/1) were selected as potential biocontrol agents. The sequencing of CHV1/ORF‐A showed that both of these virus strains belonged to the Italian subtype of CHV1. In vitro transfection of selected virus strains from hypovirulent to genetically diverse virus‐free fungal isolates and subsequent inoculation of all virus/fungus combinations on stems of genetically diverse sweet chestnut trees revealed that Croatian virus strain CR23 had an equally hypovirulent effect on the host as the strong French strain CHV1‐EP713, while M56/1 had a weaker effect. Furthermore, it was shown that in some cases, the same hypovirus‐fungus combinations induced various degrees of canker development on different chestnut genotypes. CONCLUSION Some CHV1 strains belonging to the Italian subtype have similar hypovirulent effects on C. parasitica as those belonging to the French subtype. Furthermore, chestnut susceptibility and recovery could be influenced by the response of chestnut trees to particular hypovirulent C. parasitica isolates, and virus‐fungus‐chestnut interactions could have significant implications on the success of chestnut blight biocontrol.
      PubDate: 2016-06-11T01:20:28.907136-05:
      DOI: 10.1002/ps.4335
  • Genetics, cross‐resistance and synergism of indoxacarb resistance in
           Helicoverpa armigera (Lepidoptera: Noctuidae)
    • Authors: L.J. Bird
      Abstract: BACKGROUND The cotton bollworm Helicoverpa armigera is a global pest of field and horticultural crops and has developed resistance to insecticides from many chemical classes. Indoxacarb is an important option for selective control of H. armigera in a range of crops that play host to this species. A strain of H. armigera resistant to indoxacarb (designated GY7‐39) was detected from the field by F2 screening and characterized by comparison with a near‐isogenic indoxacarb‐susceptible laboratory strain to determine inheritance, cross‐resistance profile, and synergism of indoxacarb resistance. RESULTS The level of indoxacarb resistance in the GY7‐39 was 139 to 198‐fold compared with the susceptible strain. Genetic analysis showed that resistance was autosomal, incompletely dominant, and conferred by one or a few closely linked loci. Indoxacarb resistance in the GY7‐39 strain did not confer cross‐resistance to chlorantraniliprole. The GY7‐39 was more susceptible to emamectin benzoate, fenvalerate, Cry1Ac and Cry2Ab compared with the susceptible strain. Indoxacarb resistance was synergized by the metabolic inhibitor PBO. CONCLUSIONS Rapid selection of indoxacarb resistance in the GY7‐39 strain indicates the potential risk of resistance development to indoxacarb in field populations of H. armigera. Lack of cross‐resistance indicates that resistance could be managed effectively by the use of rotational strategies which incorporate transgenic technologies. Synergism studies indicate the potential involvement of metabolic detoxification enzymes as the mechanism of resistance to indoxacarb.
      PubDate: 2016-06-10T04:45:23.863541-05:
      DOI: 10.1002/ps.4334
  • Development and implementation of a laboratory spray device and rainfall
           simulator for retention research using small amounts of
    • Authors: Ingrid K. A. Zwertvaegher; Inge Van Daele, Peter Verheesen, Marnix Peferoen, David Nuyttens
      Abstract: BACKGROUND Rainfall greatly affects the retention of foliar‐applied agro‐formulations. Improving their resistance to wash‐off is therefore of great importance in spray applications. While developing such formulations, small‐scale laboratory assays are generally required. A set‐up for retention studies using only small amounts of agro‐formulations (< 0.5 L) was developed. The set‐up consists of a spray device and a rainfall simulator. The effect of rain quantity (1, 3, 6 mm) on the spray retention of agro‐formulations was evaluated using this set‐up. RESULTS The data showed that uniform and repeatable spraying was achieved with the small‐scale spray device (CV = 23.4%) on potato pot plants (Solanum tuberosum L.). Rain quantity significantly affected the spray retention. Approximately 40% of the initial deposition was lost after 1 mm of rain at an intensity of 25 mm h−1. Additional losses decreased with increasing volumes of rain (65% and 80% loss after respectively 3 mm and 6 mm of rain). CONCLUSION Future studies could implement the set‐up to evaluate the effect of different rainfall characteristics and formulations on spray retention in order to improve the rainfastness of agro‐formulations.
      PubDate: 2016-06-10T04:22:26.578971-05:
      DOI: 10.1002/ps.4333
  • Wheat (Triticum aestivum L.)‐based intercropping systems for
           biological pest control: a review
    • Abstract: BACKGROUND Wheat Triticum aestivum L.) is one of the most cultivated crops in temperate climates. As its pests are mainly controlled with insecticides which are harmful to the environment and human health, alternative practices such as intercropping have been studied for their potential to promote biological control. Based on the published literature, this study aimed to review the effect of wheat‐based intercropping systems on insect pests and their natural enemies. RESULTS Fifty original research papers were obtained from a systematic search of the peer‐reviewed literature. Results from a vote‐counting analysis indicated that, in the majority of studies, pest abundance was significantly reduced in intercropping systems compared with pure stands. However, the occurrence of their natural enemies as well as predation and parasitism rates were not significantly increased. The country where the studies took place, the type of intercropping, and the crop that was studied in the association had significant effects on these results. CONCLUSION These findings show that intercropping is a viable practice to decrease insecticide use in wheat production systems. Nevertheless, other practices could be combined with intercropping to favour natural enemies and enhance pest control.
      PubDate: 2016-06-08T04:21:18.46591-05:0
      DOI: 10.1002/ps.4332
  • Lipopeptides from a novel Bacillus methylotrophicus 39b strain suppress
           Agrobacterium crown gall tumours on tomato plants
    • Abstract: BACKGROUND This study aims to characterize the antibacterial activity of a novel Bacillus methylotrophicus strain named 39b against tumorigenic Agrobacterium tumefaciens C58 and B6 strains. It also aims to identify the compound which is responsible for its activity and to evaluate its efficiency to control crown gall disease in tomato plants. RESULTS B. methylotrophicus strain 39b was found to stop the growth of phytopathogenic A. tumefaciens strains in in vitro experiments. Lipopeptides; surfactins, iturins and fengycins; were detected under various isoforms, by mass spectrometry analysis of the methanolic extract. The active principle acting against Agrobacterium strains was isolated from TLC plates and identified by mass spectrometry as surfactin. The strain was effective in reducing the weight and the number of galls induced by A. tumefaciens strains on tomato plants. Total inhibition of gall formation was observed using the antibacterial compounds. CONCLUSION B. methylotrophicus strain 39b exhibited antibacterial activity against phytopathogenic A. tumefaciens C58 and B6 both in vitro and in vivo. Lipopeptides are the main compounds which confer the biocontrol ability. This strain has the potential to be developed as a biological control agent for crown gall disease.
      PubDate: 2016-06-02T01:40:30.090684-05:
      DOI: 10.1002/ps.4331
  • Review of anthraquinone applications for pest management and agricultural
           crop protection
    • Authors: Shelagh T. DeLiberto; Scott J. Werner
      Abstract: We reviewed published anthraquinone applications for international pest management and agricultural crop protection from 1943–2016. Anthraquinone (AQ) is commonly found in dyes, pigments, and many plants and organisms. Avian repellents research with AQ began in the 1940s. In context of pest management, AQ is currently used as a chemical repellent, perch deterrent, insecticide, and feeding deterrent in many wild birds, and some mammals, insects, and fishes. Criteria for evaluation of effective chemical repellents include efficacy, potential for wildlife hazards, phytotoxicity, and environmental persistence. As a biopesticide, AQ often meets these criteria of efficacy for the non‐lethal management of agricultural depredation caused by wildlife. We summarize published applications of AQ for the protection of newly‐planted and maturing crops from pest birds. Conventional applications of AQ‐based repellents include pre‐plant seed treatments (e.g. corn (Zea mays L.), rice (Oryza sativa L.), sunflower (Helianthus annuus L.) wheat (Triticum spp.), millet (Panicum spp.), sorghum (Sorghum bicolor L.), pelletized feed, and forest tree species) and foliar applications for rice, sunflower, lettuce (Lactuca sativa L.), turf, sugar beets (Beta vulgaris L.), soybean (Glycine max L.), sweet corn, and nursery, fruit, and nut crops. In addition to agricultural‐repellent applications, AQ has also been used to treat toxicants for the protection of non‐target birds. Few studies have demonstrated AQ repellency in mammals, including wild boar (Sus scrofa, L.), thirteen‐lined ground squirrels (Ictidomys tridecemlineatus, Mitchill), black‐tailed prairie dogs (Cyomys ludovicainus, Ord.), common voles (Microtus arvalis, Pallas), house mice (Mus musculus, L.), Tristram's jirds (Meriones tristrami, Thomas) and black rats (Rattus rattus L.). Natural sources of AQ and its derivatives have also been identified as insecticides and insect repellents. As a natural or synthetic biopesticide, AQ is a promising candidate for many contexts of non‐lethal and insecticidal pest management.
      PubDate: 2016-06-02T01:35:30.42667-05:0
      DOI: 10.1002/ps.4330
  • Evolution of resistance to pyrethroid insecticides in Musca domestica
    • Authors: Jeffrey G. Scott
      Abstract: BACKGROUND House flies, Musca domestica L., are a significant pest because of the numerous diseases they transmit. Control of house fly populations, particularly at animal production facilities, is frequently done using pyrethroid insecticides which kill insects by prolonging the open time of the voltage sensitive sodium channel (VSSC). RESULTS House flies have evolved resistance to pyrethroids due to mutations in Vssc and by cytochrome P450‐mediated detoxification. Three Vssc mutations are known: kdr (L1014F), kdr‐his (L1014H) and super‐kdr (M918T+L1014F). Generally, the levels of resistance conferred by these mutations are kdr‐his < kdr < super‐kdr, but this pattern does not hold for multi‐halogenated benzyl pyrethroids for which super‐kdr confers less resistance than kdr. P450‐mediated resistance can result from overexpression of CYP6D1 or to another P450 (unidentified) whose overexpression is linked to autosomes II or V. CONCLUSIONS The initial use of field‐stable pyrethroids resulted in different patterns of evolution across the globe, but with time these mutations have become more widespread in their distribution. What is known about the fitness costs of the resistance alleles in the absence of insecticide is discussed, particularly with respect to the current and future utility of pyrethroid insecticides.
      PubDate: 2016-05-31T02:00:41.407397-05:
      DOI: 10.1002/ps.4328
  • Field evaluation of the nematicide fluensulfone for control of the potato
           cyst nematode Globodera pallida
    • Authors: Patrick M Norshie; Ivan G Grove, Matthew A Back
      Abstract: BACKGROUND Three field experiments evaluated the performance of the nematicide fluensulfone against the potato cyst nematode Globodera pallida in Shropshire, England. RESULTS Experiments 1 and 2 showed reduced root infection and lowered multiplication of G. pallida following fluensulfone (Nimitz 15G®) soil treatments at five rates (1.95, 3.00, 4.05 (full rate), 5.05 and 6.00 kg a.s. ha−1), and Nimitz 480EC® at the full rate. Experiment 3 demonstrated a positive interaction between the full rate of Nimitz 15G® and the potato variety Santé in the reduction of G. pallida. The fluensulfone treatments at the full rate had more consistent effects than the lower rates, and there were no greater effects for the treatments higher than this full rate. Generally, fluensulfone was less efficacious than oxamyl or fosthiazate, which suggests that the treatment may not be reliably integrated within shorter potato rotations CONCLUSION The data suggest that fluensulfone soil application could make a useful addition to the few available nematicide treatments for the control of G. pallida rather than be a substitute for these treatments.
      PubDate: 2016-05-31T02:00:36.604497-05:
      DOI: 10.1002/ps.4329
  • Susceptibility of Alphitobius diaperinus in Texas to permethrin and
           β‐cyfluthrin treated surfaces
    • Authors: Brandon N. Lyons; Tawni L. Crippen, Le Zheng, Pete D. Teel, Sonja L. Swiger, Jeffery K. Tomberlin
      Abstract: BACKGROUND Effective control of the lesser mealworm beetle, Alphitobius diaperinus, relies heavily on insecticides. Susceptibility level of beetles to these insecticides can be dependent on active ingredient, population treated, formulation, surface treated and timing of observation. The susceptibility of adult beetles from six populations to β‐cyfluthrin was determined up to 48 hours after exposure. Susceptibility of adult beetles to the label rate of β‐cyfluthrin and permethrin formulations on concrete, wood chip‐type particleboard, and pressure treated wood was determined up to 48 hours post exposure. RESULTS Variation in LC50’s at 2 and 24 hours were found within and between beetle populations from two regions of Texas, USA sampled at 2 and 24 h. The permethrin formulation had lower mean mortality than the β‐cyfluthrin formulation on all surfaces tested. The permethrin formulation had high levels of recovery on all surfaces tested after 2 h. Surface affected the efficacy of the insecticides tested on killing adult beetles. CONCLUSION Permethrin‐based insecticide had lower knockdown and persistence on various surfaces over time than β‐cyfluthrin‐based insecticide. Beetle recovery in less‐ susceptible populations may necessitate longer observation periods for efficacy evaluations. Our study also shows that surfaces chosen can affect efficacy of the compound on killing adult beetles.
      PubDate: 2016-05-30T15:45:25.499968-05:
      DOI: 10.1002/ps.4327
  • Long‐term population patterns of rodents and associated damage in
           German forestry
    • Abstract: BACKGROUND Several rodent species can damage forest trees especially at young tree age in afforestation. Population outbreaks of field voles (Microtus agrestis L.) and bank voles (Myodes glareolus Schreber) in particular can cause losses. RESULTS Analyses of long‐term time‐series indicate good synchrony of population abundance in rodent species associated with damage in forestry. This synchrony could be related to the effect of beech (Fagus spec.) mast in the previous year on population growth rates of both species. In shorter time‐series from Eastern Germany, damage in forestry was mostly associated with autumn abundances of rodents. Environmental factors like beech mast and snow cover did not explain additional variation in rodent damage to trees. CONCLUSIONS Beech mast is a good indicator of long‐term rodent abundance in Northern German afforestation areas. However, rodent damage to forestry in Central Germany did not seem to depend on environmental parameters other than rodent abundance at the large scale. As a result, there is still uncertainty on the link between environmental predictors and rodent damage to forestry and further experimental work is required to identify suitable environmental drivers and their interplay with other potential factors such as the local predator community.
      PubDate: 2016-05-28T01:20:29.581305-05:
      DOI: 10.1002/ps.4325
  • Sublethal dose of Phoxim and Bombyx mori nucleopolyhedrovirus interact to
           elevate silkworm mortality
    • Authors: ZhiYa Gu; FanChi Li, JingSheng Hu, Chao Ding, Zhaoqian Wang, JiangHai Tian, Bin Xue, KaiZun Xu, WeiDe Shen, Bing Li
      Abstract: BACKGROUND Silkworm (Bombyx mori) is an economically important insect. It is relatively less resistant to certain chemicals and environment exposures, such as pesticides and pathogens. After pesticide exposures, the silkworms are more susceptible to microbial infections. The mechanism underlying the susceptibility might be related to immune response and oxidative stress. RESULTS Sublethal dose of phoxim combined with Bombyx mori nucleopolyhedrovirus (BmNPV) elevated the silkworm mortality at 96 h. We found higher content of H2O2 and increased levels of genes related to oxidative stress and immune response after treatment with sublethal dose of phoxim for 24 h or 48 h. However, such response decreased with longer pesticide treatment. The mortality increased 44% when B. mori was exposed to combined treatment with BmNPV and phoxim than BmNPV alone. The level of examined immune‐related and oxidative stress‐related genes significantly decreased in combined treatment group than those in BmNPV group. Our results indicated that with long‐term exposure to pesticides, such as OPs even at sublethal dose, the oxidative stress response and immune responses in silkworm were inhibited, which may lead to further immune impairment and accumulation of oxidative stress, resulting in the susceptibility to virus and harm to silkworm. CONCLUSION Our study provided insights for understanding the susceptibility to pathogen after pesticide exposures, which may promote the development of better pesticide controls to avoid significant economic losses.
      PubDate: 2016-05-25T01:45:27.684546-05:
      DOI: 10.1002/ps.4326
  • RNAi as a management tool for the western corn rootworm, Diabrotica
           virgifera virgifera
    • Abstract: The western corn rootworm (WCR), Diabrotica virgifera virgifera, is the most important pest of corn in the U.S. Corn Belt. Economic estimates indicate that costs of control and yield loss associated with WCR damage exceed $1 billion annually. Historically, corn rootworm management has been extremely difficult because of its ability to evolve resistance to both chemical insecticides and cultural control practices. Since 2003, the only novel commercialized developments in rootworm management have been transgenic plants expressing Bt insecticidal proteins. Four transgenic insecticidal proteins are currently registered for rootworm management, and field resistance to proteins from the Cry3 family highlights the importance of developing traits with new modes of action. One of the newest approaches for controlling rootworm pests involves RNA interference (RNAi). This review describes the current understanding of the RNAi mechanisms in WCR and the use of this technology for WCR management. Further, the review addresses the ecological risk assessment of RNAi and insect resistance management of RNAi for corn rootworm.
      PubDate: 2016-05-24T02:16:29.191577-05:
      DOI: 10.1002/ps.4324
  • Phthalimide‐Derived Strigolactone Mimics as Germinating Agents for
           Seeds of Parasitic Weeds
    • Abstract: BACKGROUND Broomrapes attack important crops, cause severe yield losses and they are difficult to eliminate because their seed bank is virtually indestructible. In the absence of a host, the induction of seed germination leads to inevitable death due to nutrient starvation. Synthetic analogs of germination‐inducing factors may constitute a cheap and feasible strategy to control the seed bank. These compounds should be easy and cheap to synthesize as this will allow their mass production. The aim of this work is to obtain new synthethic germinating agents. RESULTS Nineteen N‐substituted phthalimides containing a butenolide ring and different substituents in the aromatic ring were synthesized. The synthesis started with commercially available phthalimides. The complete collection was assayed against the parasitic weeds Orobanche minor, O. cumana, Phelipanche ramosa and P. aegyptiaca, with the synthetic strigolactone analog GR24 used as a positive control. This compounds offered low EC50 values: O. cumana 38.3 μM, O. minor 3.77 μM, P. aegyptiaca 1.35 μM and P. ramosa 1.49 μM. CONCLUSIONS The synthesis was carried out in few steps and provided the target compounds in good yields. The compounds tested showed great selectivity and low EC50 values were obtained for structures that were simpler than GR24.
      PubDate: 2016-05-24T02:16:28.007957-05:
      DOI: 10.1002/ps.4323
  • The consequences of sublethal exposure to insecticide on the survivorship
           and mobility of Halyomorpha halys (Hemiptera: Pentatomidae)
    • Authors: William R. Morrison III; Brittany Poling, Tracy C. Leskey
      Abstract: BACKGROUND The direct lethal effects of conventional and organic insecticides have been investigated thoroughly for all life stages of H. halys. However, the sublethal effects of insecticides on the behavior of H. halys have not been well‐documented. Our aims were to evaluate the impact of a brief 5‐min exposure to residues of bifenthrin, dinotefuran, methomyl, thiamethoxam, and thiamethoxam + λ‐cyhalothrin on survivorship, horizontal and vertical movement, and flight capacity of adult H. halys under laboratory conditions. RESULTS Over half of the insecticide‐exposed adults were classified as affected, moribund, or dead after the 5‐min exposure, compared with only 6% of the adults in the water‐only control. We found that the horizontal movement, vertical climbing, and flight capacity of adults exposed to insecticides were decreased by 20‐60% overall relative to the water‐only control. The most lethal insecticide was bifenthrin. CONCLUSION Many insecticide‐exposed H. halys adults retained significant mobility and flight capacity, with flight most pronounced immediately after exposure. These results suggest that brief exposure periods to efficacious insecticides will result in high dispersal and low mortality. Therefore, management strategies that enhance the retention of H. halys on insecticide‐coated surfaces should be considered to ensure adults are exposed to a lethal dose of insecticide.
      PubDate: 2016-05-23T01:55:27.295989-05:
      DOI: 10.1002/ps.4322
  • Sugar Concentration in Nectar: A Quantitative Metric of Crop
           Attractiveness for Refined Pollinator Risk Assessments
    • Authors: Loren D. Knopper; Tereza Dan, Dominic D. Reisig, Josephine D. Johnson, Lisa M. Bowers
      Abstract: Those involved with pollinator risk assessment know that agricultural crops vary in attractiveness to bees. Intuitively this means that exposure to agricultural pesticides is likely greatest for attractive plants and lowest for unattractive plants. While crop attractiveness in the risk assessment process has been qualitatively remarked on by some authorities, absent is direction on how to refine the process with quantitative metrics of attractiveness. At a high level, attractiveness of crops to bees appears to depend on several key variables, including but not limited to: floral, olfactory, visual and tactile cues, seasonal availability, physical and behavioral characteristics of the bee and plant, and nectar rewards. Notwithstanding the complexities and interactions amongst these variables, sugar content in nectar stands out as a suitable quantitative metric by which to refine pollinator risk assessments for attractiveness. Provided herein is a proposed way to use sugar nectar concentration to adjust the exposure parameter (with what is called a Crop Attractiveness Factor) in the calculation of risk quotients in order to derive crop‐specific Tier I assessments. This Perspective is meant to invite discussion on incorporating such changes in the risk assessment process.
      PubDate: 2016-05-20T02:11:11.637034-05:
      DOI: 10.1002/ps.4321
  • Temperature variability is a key component to accurately forecast the
           effects of climate change on pest phenology
    • Authors: Scott C. Merrill; Frank B. Peairs
      Abstract: Background Models describing the effects of climate change on arthropod pest ecology are needed to help mitigate and adapt to forthcoming changes. Challenges arise because climate data are at resolutions that do not readily synchronize with arthropod biology. Here we explain how multiple sources of climate and weather data can be synthesized to quantify the effects of climate change on pest phenology. Results Predictions of phenological events differ substantially between models that incorporate scale‐appropriate temperature variability and models that do not. As an illustrative example, we predicted adult emergence of a pest of sunflower, Cylindrocopturus adspersus (LeConte). Predictions of the timing of phenological events differed by an average of 11 days between models with different temperature variability inputs. Moreover, as temperature variability increases developmental rates accelerate. Conclusions Our work details a biologically‐relevant phenology modeling approach for pests with results designed to help mitigate the effects of climate change. Results show that selection of scale appropriate temperature data is of more importance than selecting a climate change emission scenario or Representative Concentration Pathway. Predictions derived without appropriate temperature variability inputs will likely result in substantial phenological event miscalculations. Additionally, results suggest that increased temperature instability will lead to accelerated pest development.
      PubDate: 2016-05-16T02:50:43.347123-05:
      DOI: 10.1002/ps.4320
  • Study of the efficiency of anticoagulant rodenticides to control Mus
           musculus domesticus introgressed with Mus spretus Vkorc1
    • Abstract: BACKGROUND Antivitamin K anticoagulant (AVK) rodenticides are commonly used to control rodent pests worldwide. They specifically inhibit the VKORC1 enzyme essential for the recycling of vitamin K, and thus prevent blood clotting and cause death by haemorrhage. Numerous mutations or polymorphisms of the Vkorc1gene were reported in rodents and some lead to resistance to rodenticides. In house mice (Mus musculus domesticus), adaptative introgression of the Vkorc1 gene from the Algerian mouse (Mus spretus) was reported. This adaptative introgression causes the substitution of four amino acids in M. musculus domesticus. RESULTS The consequences of introgression were assessed by (i) the characterization of the in vivo resistant phenotype of adaptative Vkorc1spr‐introgressed mice, (ii) the characterization of the ex vivo resistance phenotype of the liver VKOR activity and (iii) the comparison of these results with the properties of recombinant VKORC1spr protein expressed in yeast. The resistance factor (from 1 to 120) induced by the four introgressed polymorphisms obtained using these three approaches was dependent on the used AVKs but were highly correlated among the three approaches. CONCLUSION The 4 introgressed polymorphisms were clearly the cause of the strong resistant phenotype observed in the field. In the context of strong selection pressure due to the extensive use of AVK, this resistant phenotype may explain the widespread distribution of this genotype from Spain to Germany.
      PubDate: 2016-05-16T02:50:16.806926-05:
      DOI: 10.1002/ps.4319
  • Structure, function and management of semi‐natural habitats for
           conservation biological control: A review of European studies
    • Abstract: Different semi‐natural habitats occur on farmland and it is the vegetation's traits and structure that subsequently determine their ability to support natural enemies and their associated contribution to conservation biocontrol. New habitats can be created and existing ones improved with agri‐environment scheme funding in all EU member states. Understanding the contribution of each habitat type can aid the development of conservation control strategies. Here we review the extent to which the predominant habitat types in Europe support natural enemies, whether this results in enhanced natural enemy densities in the adjacent crop, and whether this leads to reduced pest densities. Considerable variation exists in the available information for the different habitat types and trophic levels. Natural enemies within each habitat were the most studied, with less information on whether they were enhanced in adjacent fields, whilst their impact on pests was rarely investigated. Most information was available for woody and herbaceous linear habitats, yet not for woodland that can be the most common semi‐natural habitats in many regions. While the management and design of habitats offers potential to stimulate conservation biocontrol we also identified knowledge gaps. A better understanding of the relationship between resource availability and arthropod communities across habitat types, the spatio‐temporal distribution of resources in the landscape, and interactions with other factors that play a role in pest regulation could contribute to an informed management of semi‐natural habitats for biocontrol.
      PubDate: 2016-05-14T00:16:45.866127-05:
      DOI: 10.1002/ps.4318
  • The interactions between piperonyl butoxide and analogues with the
           metabolic enzymes FE4 and CYP6CY3 of the green peach aphid Myzus persicae
           (Hemiptera: Aphididae)
    • Authors: Michela Panini; Francesco Tozzi, Chris Bass, Christoph T. Zimmer, Linda Field, Valerio Borzatta, Emanuele Mazzoni, Graham Moores
      Abstract: BACKGROUND Piperonyl butoxide (PBO) is a well‐known insecticide synergist capable of interacting with phase 1 metabolic enzymes, specifically esterases and cytochrome P450s. In this study, structure activity relationship (SAR) analyses were used to characterise the interaction of around 30 analogues of PBO with the esterase FE4 and the P450 CYP6CY3 from insecticide resistant Myzus persicae (Sulzer), in order to predict the synthesis of more potent inhibitors. RESULTS Enzyme inhibition studies were performed against esterase and oxidase activities and together with in silico modelling, key activity determinants of the analogues were identified and optimised. Novel analogues were then designed and synthesised, some of which showed greater inhibition against both enzymatic systems: specifically, dihydrobenzofuran moieties containing an alkynyl side chain and a butyl side chain against FE4, and benzodioxole derivatives with a propyl/butyl side chain and an alkynyl ether moiety for CYP6CY3. CONCLUSIONS In vitro assays identified potential candidate synergists with high inhibitory potency. The in vivo confirmation of such results will allow consideration for a possible use in agriculture.
      PubDate: 2016-05-13T04:50:49.296776-05:
      DOI: 10.1002/ps.4314
  • The Importance of Regulatory Data Protection or Exclusive Use and other
           forms of Intellectual Property Rights in the Crop Protection Industry
    • Authors: Michael J. Carroll
      Abstract: BACKGROUND In order for a chemical plant protection product to be authorised for sale a registration dossier has to be assembled to demonstrate safety and efficacy to the satisfaction of government regulators. These studies and tests are protected for a period of 10 years in Europe, North America and some other jurisdictions from the date of first product authorisation so that only the data owner can gain commercial benefit from the data. RESULTS After first product authorisation the USA, Canada, Australia and Brazil give 10 years of data protection exclusive use for the safety and efficacy data necessary for the regulatory decision. At subsequent regulatory review financial compensation is payable to the data owner for new studies. The EU system offers sequential regulatory data protection exclusive use with compensation for vertebrate studies which can lead to confusion. CONCLUSION Data protection exclusive use is a time limited intellectual property right that gives the data owner a period of 10 years in Europe and North America whereby no other company can use the data for commercial gain. Subsequent regulatory reviews should not result in further periods of regulatory data protection exclusive use but compensation should be payable to the data generator.
      PubDate: 2016-05-13T04:50:45.944898-05:
      DOI: 10.1002/ps.4316
  • Not in my backyard: effectiveness of outdoor residual spraying from
           hand‐held sprayers against the mosquito Aedes albopictus in Rome,
    • Abstract: BACKGROUND WHO guidelines state that adulticide interventions are recommended only in case of disease outbreak. However, peridomestic sprayings are carried out routinely to reduce Aedes albopictus (Skuse) nuisance, at least in Italy. Failing in keeping low adult abundance overtime triggers the need for further applications. The aim of the study was to investigate the effectiveness of a common control strategy routinely performed by citizens in highly infested urban sites inside the metropolitan city of Rome using a freely purchasable pyrethroid and a hand‐held sprayer. Moreover, the effectiveness evaluated in three field experiments was compared to the one achieved by blending the pyrethroid with a new carbon‐based liquid additive. RESULTS 86% post‐treatment reduction in Ae. albopictus abundance was observed in gravid and host‐seeking females, while the population recovery time was 10 days. Blending the insecticide with the additive lengthened mosquito recovery time over 14 days. CONCLUSION Peridomestic sprayings largely reduce mosquito population immediately after treatment but fail to keep low mosquito abundance on a longer period, partially explaining the uncontrolled repetitions of treatments. An optimal control application could benefit from research in the field of additive to improve the mosquito abatement and the overtime performances of pyrethroids.
      PubDate: 2016-05-13T04:50:43.673534-05:
      DOI: 10.1002/ps.4315
  • A generalised individual‐based algorithm for modelling the evolution
           of quantitative herbicide resistance in arable weed populations
    • Authors: Chun Liu; Melissa E. Bridges, Shiv S. Kaundun, Les Glasgow, Micheal D. K. Owen, Paul Neve
      Abstract: BACKGROUND Simulation models are useful tools for predicting and comparing the risk of herbicide resistance in weed populations under different management strategies. Most existing models assume a monogenic mechanism governing herbicide resistance evolution. However, growing evidence suggests that herbicide resistance is often inherited in a polygenic or quantitative fashion. Therefore, we constructed a generalised modelling framework to simulate the evolution of quantitative herbicide resistance in summer annual weeds. RESULTS Real‐field management parameters based on Amaranthus tuberculatus (Moq.) Sauer (syn. rudis) control with glyphosate and mesotrione in the Midwestern U.S. maize‐soybean agroecosystems demonstrated that the model can represent evolved herbicide resistance in realistic timescales. Sensitivity analyses showed that genetic and management parameters were impactful on the rate of quantitative herbicide resistance evolution, whilst biological parameters such as emergence and seed bank mortality were less important. CONCLUSION The simulation model provides a robust and widely applicable framework for predicting the evolution of quantitative herbicide resistance in summer annual weed populations. The sensitivity analyses identified weed characteristics that would favour herbicide resistance evolution, including high annual fecundity, large resistance phenotypic variance and pre‐existing herbicide resistance. Implications for herbicide resistance management and potential use of the model are discussed.
      PubDate: 2016-05-13T04:50:33.370933-05:
      DOI: 10.1002/ps.4317
  • Larval Western bean cutworm feeding damage encourages the development of
           Gibberella ear rot on field corn
    • Authors: Nicole S. Parker; Nolan R. Anderson, Douglas S. Richmond, Elizabeth Y. Long, Kiersten A. Wise, Christian H. Krupke
      Abstract: BACKGROUND A two year study was conducted to determine if western bean cutworm (Striacosta albicosta Smith) (WBC) larval feeding damage increases severity of the fungal disease Gibberella ear rot (Fusarium graminearum (Schwein.) Petch in field corn (Zea mays L.). The effect of a QoI fungicide, pyraclostrobin, on Gibberella ear rot severity and mycotoxin production, both with and without WBC pressure, was also evaluated. The impact of each variable was assessed individually and in combination to determine the effect of each upon ear disease severity. RESULTS There was a positive correlation between the presence of WBC larvae in field corn and Gibberella ear rot severity under inoculated conditions in two years of the experiment. An application of pyraclostrobin did not impact Gibberella ear rot development when applied at corn growth stage R1 (silks first emerging). CONCLUSION Feeding damage from WBC larvae significantly increases the development of F. graminearum in field corn. We conclude that an effective integrated management strategy for Gibberella ear rot should target the insect pest first, in an effort to limit disease severity and subsequent mycotoxin production by F. graminearum in kernels.
      PubDate: 2016-05-09T09:11:43.117516-05:
      DOI: 10.1002/ps.4313
  • Fitness costs and stability of Cry1Fa resistance in Brazilian populations
           of Spodoptera frugiperda
    • Abstract: BACKGROUND The presence of fitness costs of resistance to Bacillus thuringiensis (Bt) insecticidal proteins in insect populations may delay or even reverse the local evolution of insect resistance to Bt transgenic crops, deserving rigorous investigation. Here we assessed the fitness costs associated with Cry1Fa resistance in two fall armyworm strains [Spodoptera frugiperda (Lepidoptera: Noctuidae)] derived from field collections in different Brazilian regions and further selected in the laboratory for high levels of resistance to Cry1Fa using leaves of TC1507 corn. RESULTS Fitness components were compared using paired resistant and susceptible strains with similar genetic background and F1 generations from reciprocal crosses, all of them reared on non‐transgenic corn leaves. No apparent life‐history costs in the larval stage were observed in the Bt resistant strains. Moreover, the resistance remained stable for seven generations in the absence of selection with no decrease in the proportion of resistant individuals. Larval respiration rates were also similar between resistant and susceptible homozygotes, and heterozygotes displayed respiration rates and demographic performance equal or superior to that of susceptible homozygotes. CONCLUSION In combination, these results indicate lack of strong fitness costs associated with resistance to Cry1Fa in the fall armyworm strains studied. These findings suggest that Cry1Fa resistance in S. frugiperda populations is unlikely to be counter‐selected in Cry1Fa‐free environments.
      PubDate: 2016-05-05T02:05:35.437732-05:
      DOI: 10.1002/ps.4312
  • It Takes a Team: Reflections on Insecticide Discoveries, Toxicological
           Problems and Enjoying the Unexpected
    • Authors: Keith D. Wing
      Abstract: ADME (Absorbtion/Distribution/Metabolism/Excretion)–related studies are mandatory in agrochemical development/registration, but can also play a valuable role in the discovery process. In combination with target site potency, bioavailability/ADME characteristics determine agrochemical bioactivity and selectivity, and these concerns can dictate the fate of a discovery lead area. Bioavailability/ADME research was critical to the eventual commercialization of three different insecticide chemistries examined in this paper. In one situation, improved systemicity in anthranilic diamides was required to expand pest spectrum. In another, ADME tools were needed to improve the selective toxicity and nontarget safety of sodium channel blocker insecticides. Finally, differential ADME characteristics of two classes of hormone agonists dictated differential insecticidal activity, and were useful in optimizing the dibenzoylhydrazine ecdysone agonists. ADME discovery research will help companies to advance novel, efficacious and selective agrochemicals, but organizational patience and a desire to understand lead areas in depth are required.
      PubDate: 2016-05-05T02:05:27.994215-05:
      DOI: 10.1002/ps.4311
  • Laboratory studies of insecticide efficacy and resistance in Drosophila
           suzukii (Matsumura) (Diptera: Drosophilidae) populations from British
           Columbia, Canada
    • Abstract: BACKGROUND Drosophila suzukii (Matsumura), spotted wing drosophila (SWD), control can be improved with better knowledge of insecticide efficacy, timing of sprays, and rotations with registered products during the crop year. An efficacy bioassay was applied to study the dose–response of adult laboratory‐reared SWD collected from a cherry orchard in British Columbia (BC), Canada, to 11 insecticides. RESULTS Age and sex specific toxicities with the most effective insecticide, malathion, determined that older male SWD were significantly more susceptible than females. The selection for polygenic resistance to malathion using repeated exposure to sub‐lethal concentrations with both the original and an additional blueberry‐collected population of laboratory reared SWD determined no significant difference in susceptibility after 30 generations. CONCLUSION Possible reasons reported in Drosophila melanogaster studies where resistance did not occur after insecticide selection included avoidance and associated microbial complexes. The low level of malathion‐resistance observed in the selected SWD populations and a field‐collected population is useful information in the development of insecticide resistance management programs.
      PubDate: 2016-05-05T02:00:24.38099-05:0
      DOI: 10.1002/ps.4310
  • An artificial diet containing plant pollen for the mealybug predator
           Cryptolaemus montrouzieri
    • Authors: Jiaqin Xie; Hongsheng Wu, Hong Pang, Patrick De Clercq
      Abstract: BACKGROUND The specialist predatory ladybird Cryptolaemus montrouzieri is an effective natural enemy of mealybugs and plays a key role in the biological control of these pests. However, its mass production is complicated by the dependence on parallel cultures of mealybugs or the need for Ephestia kuehniella eggs as an expensive factitious prey. RESULTS Here we developed a pollen‐based artificial food for the predator to lower its dependence on natural prey. We found that this artificial diet was an effective alternative food for larvae and adults of this predator. The artificial food not only supported the development and reproduction of the predator in the first generation (F0) but also in the next generation (F1). Although the developmental time and preoviposition period of C. montrouzieri on the artificial food were ca. 1.5 days and 4 days longer than on the natural prey, the citrus mealybug Planococcus citri, respectively, its immature survival, fecundity and egg hatch were similar to that on mealybugs. In addition, adult C. montrouzieri maintained on natural or artificial food had a similar starvation resistance. CONCLUSIONS Our results suggest that the pollen‐based artificial diet can be used as an alternative food in the rearing of C. montrouzieri, and indicate its potential to support the mass production and wider application of this predator in biological control programs.
      PubDate: 2016-05-05T02:00:20.778774-05:
      DOI: 10.1002/ps.4309
  • A Retrospective Look at Anthranilic Diamide Insecticides: Discovery and
           Lead Optimization to Chlorantraniliprole and Cyantraniliprole
    • Authors: Thomas P. Selby; George P. Lahm, Thomas M. Stevenson
      Abstract: Anthranilic diamides are an important commercial synthetic class of insecticides (IRAC Group 28) that bind to the ryanodine receptor with selective potency against insect versus mammalian forms of the receptor. The first commercialized diamide, chlorantraniliprole, has exceptional activity against Lepidopteran pests. The second anthranilamide product, cyantraniliprole, has excellent cross‐spectrum activity against a range of insect orders, including both Lepidopteran and Hemipteran pests. Here, a retrospective look is presented on the discovery of the class along with chemistry highlights of the lead evolution to both products.
      PubDate: 2016-05-05T01:55:24.41971-05:0
      DOI: 10.1002/ps.4308
  • Novel and current rodenticides for pocket gopher Thomomys spp. management
           in vineyards: what works?
    • Authors: Roger A. Baldwin; Ryan Meinerz, Gary W. Witmer
      Abstract: Background Rodenticides are often included as part of an IPM approach for managing pocket gophers (Thomomys spp.) given that they are relatively quick and inexpensive to apply. Strychnine has historically been the most effective toxicant for pocket gophers, but its use is currently limited in the U.S.; alternative registered toxicants have not proven effective. Recent research with baits containing cholecalciferol plus anticoagulant toxicants proved effective against pocket gophers in a lab setting. Therefore, we established a field study to compare cholecalciferol plus anticoagulant combinations (0.03% cholecalciferol plus 0.005% diphacinone [C + D], 0.015% cholecalciferol plus 0.0025% brodifacoum [C+B1], 0.03% cholecalciferol plus 0.0025% brodifacoum [C+B2]) to strychnine (0.5%) for pocket gopher management. Results Strychnine treatments resulted in 100% efficacy after two treatment periods. Both C + D and C+B2 resulted in efficacy significantly greater than 70% after two treatment periods (83% and 75%, respectively). Efficacy from C+B1 (85%) was not significantly greater than 70%, but did yield high overall efficacy as well. Conclusion Although strychnine remains the most effective rodenticide for pocket gopher control, the cholecalciferol plus anticoagulant baits tested would be a good alternative when strychnine is unavailable. C + D may be the best option given that it uses a first‐generation anticoagulant as the synergist.
      PubDate: 2016-05-03T00:41:27.404309-05:
      DOI: 10.1002/ps.4307
  • Competition between the phytophagous stink bugs Euschistus heros and
           Piezodorus guildinii in soybeans
    • Abstract: BACKGROUND The abundance and contribution of the Neotropical brown stink bug, Euschistus heros (F.), and the redbanded stink bug, Piezodorus guildinii (West.), to the composition of insect pests of soybean, Glycine max (L.), fields have changed both spatially and temporally in Neotropical soybean production areas. Therefore, we assessed the competitiveness of each species in direct competition experiments following an additive series. We performed mixed (adult) insect infestations in soybean plants and evaluated the fitness of each species and the soybean yield. RESULTS While the competitive ability of E. heros was significantly compromised by increments in conspecifics and heterospecifics (i.e., P. guildinii), the competitive ability of P. guildinii was compromised by the presence of heterospecifics (i.e., E. heros). The reproductive output of P. guildinii remained unaffected by increments of E. heros or of P. guildinii. Intriguingly, despite the fact that P. guildinii apparently lost the competition with E. heros, almost no pod production was observed in any plant colonized by the former. CONCLUSIONS The higher abundance of E. heros on Neotropical soybean fields seems to result from higher competitive ability than its heterospecific competitor P. guildinii, which may prevent the higher losses caused by P. guildinii.
      PubDate: 2016-04-30T05:05:41.457121-05:
      DOI: 10.1002/ps.4306
    • Abstract: BACKGROUND Acibenzolar‐S‐methyl (BTH), a functional analog of Salicylic Acid (SA), is known to elicit a systemic resistance across a broad range of plant–pathogen interactions but, so far, it was not tested against Flavescence dorée (FDP), one of the most devastating grapevine diseases. Aims of this work were to evaluate the activity of BTH in preventing FDP transmission by the insect vector and in inducing recovery of infected grapevines. RESULTS Repeated applications of 2 mM BTH to test grapevine cuttings (cv Barbera) exposed to adults of the infectious vector, Scaphoideus titanus Ball, reduced the rate of infected plants. The effect was not recorded following similar BTH applications to highly susceptible young in vitro propagated vines. A high natural recovery rate (more than 70%) was observed over a three‐year‐period in field‐infected grapevines of the same cv. Under these conditions, BTH repeated applications over the whole period clearly failed to increase recovery of field‐infected grapevines. CONCLUSION Following a three‐year experiment, it can be concluded that, although high doses and repeated applications of BTH reduced vector transmission of FDP, BTH was ineffective in inducing recovery of FDP‐infected grapevines cv Barbera under field conditions.
      PubDate: 2016-04-27T01:31:09.45451-05:0
      DOI: 10.1002/ps.4303
  • Vkorc1‐sequencing suggests anticoagulant resistance in rats in New
    • Abstract: BACKGROUND Anticoagulant toxins are used globally to control rats. Resistance of Rattus species to these toxins now occurs in at least 18 countries in Europe, America, and Asia. Resistance is often associated with single nucleotide polymorphisms (SNP) in the Vkorc1 gene. This study gives a first overview of the distribution and frequency of Vkorc1 SNPs in rats in New Zealand. New Zealand is unusual in having no native rodents but three species of introduced Rattus – norvegicus Berk., rattus L. and exulans Peale. RESULTS Sequence variants occurred in at least one species of rat at all 30 of the sites sampled. Three new SNPs were identified, one in kiore and two in ship rats. No SNPs previously associated with resistance were found in Norway rats or kiore, but seven ship rats were heterozygous and one homozygous for the A74T variant. Its resultant Tyr25Phe mutation has previously been associated with resistance to both first and second generation anticoagulants in ship rats in Spain. CONCLUSIONS This is the first evidence of potential resistance to anticoagulant toxins in rats in New Zealand. Further testing using blood clotting response times in dosed rats is needed to confirm resistance potentially conferred by the Tyr25Phe mutation. Assessment is also needed of the potential of the other non‐synonymous variants (Ala14Val, Ala26Val) recorded in this study to confer resistance to anticoagulant toxins.
      PubDate: 2016-04-27T01:30:55.563106-05:
      DOI: 10.1002/ps.4304
  • Linking pollen quality and performance of Neoseiulus californicus (Acari:
           Phytoseiidae) in two‐spotted spider mite management programmes
    • Authors: Mostafa Khanamani; Yaghoub Fathipour, Ali Asghar Talebi, Mohammad Mehrabadi
      Abstract: BACKGROUND It has been shown that pollen as a dietary supplement may increase the establishment of generalist predatory mites, and therefore pest control by these mites can be provided. Life table studies were performed to evaluate the nutritional value of seven different pollens (almond, castor‐bean, date‐palm, maize, bitter‐orange, sunflower and mixed bee pollen) as a supplementary food source for the spider mite predator, Neoseiulus californicus McGregor. In addition, the nutritional quality of each pollen species was assessed through morphological and chemical analysis. RESULTS Preadult duration was longer when the predator fed on castor‐bean pollen (10.01 days) and bee pollen (9.94 days) compared with the others (5.58 ‐7.27 days). The cohort reared on almond pollen had the highest intrinsic rate of increase (r) (0.231 day−1), and those on mixed bee pollen had the lowest r (0.005 day−1). The levels of nutritional content (sugar, lipid and protein) were significantly different among tested pollens. CONCLUSIONS Comparison of N. californicus life table parameters on different diets revealed that the almond pollen (and after that the maize pollen) was a more suitable diet than the others. These findings will be useful to develop appropriate strategies for conservation of N. californicus to control the spider mites.
      PubDate: 2016-04-27T01:30:25.414719-05:
      DOI: 10.1002/ps.4305
  • Influence of Soil Properties and Soil Moisture on the Efficacy of
           Indaziflam and Flumioxazin on Kochia scoparia L.
    • Authors: Derek Sebastian; Scott Nissen, Phil Westra, Dale Shaner, Greg Butters
      Abstract: BACKGROUND Kochia (Kochia scoparia L.) is a highly competitive, non‐native weed found throughout the western US. Flumioxazin and indaziflam are two broad spectrum preemergence herbicides that can control kochia in a variety of crop and non‐crop situations; however, under dry conditions, these herbicides sometimes fail to control this important weed. There is very little information describing the effect of soil properties and soil moisture on the efficacy of these herbicides. RESULTS Soil organic matter (SOM) explained the highest proportion of variability in predicting the herbicide dose required for 80 percent kochia growth reduction (GR80) for flumioxazin and indaziflam (r2 = 0.72 and 0.79, respectively). SOM had a larger impact on flumioxazin phytotoxicity compared to indaziflam. Flumioxazin and indaziflam kochia phytotoxicity was greatly reduced at soil water potentials below −200 kPa. CONCLUSION Kochia can germinate at soil moisture potentials below the moisture required for flumioxazin and indaziflam activation, which means that kochia control is greatly influenced by the complex interaction between soil physical properties and soil moisture. This research can be used to better understand how and why some weeds, like kochia, are so difficult to manage even with herbicides that normally provide excellent control.
      PubDate: 2016-04-25T00:30:36.611993-05:
      DOI: 10.1002/ps.4300
  • Dust drift reduction effect of an air conveyor kit (dual pipe deflector)
           mounted on different maize pneumatic drills
    • Authors: Marco Manzone; Paolo Balsari, Paolo Marucco, Mario Tamagnone
      Abstract: BACKGROUND All maize drills produce a fine dust due to the abrasions of the seed coating that occur inside the seeding element. Nevertheless, the air stream generated by the fan of pneumatic drills – necessary to create a depression in the sowing element of the machine and to guarantee a correct seeds deposition – can blow away the solid particles detached from the seeds. In order to reduce this phenomena, coated maize seeds company (Syngenta®) has set up an ad hoc kit “dual pipe deflector” that easy a fits different pneumatic drills (also old drills). In this study, the efficiency of this kit and the influence of different drills types on the kit effects in reducing the environmental contamination, were evaluated using three different pneumatic seed drills models. RESULTS The research showed that dual pipe deflector installed on the drill in standard configuration did not change the seeder performance and using this kit on pneumatic drills, independent of their design, it is possible to reduce up to 69% the amount of dust drift with respect to the conventional machine set up. CONCLUSION Dual pipe deflector, under conditions explained in this experimentation, showed good performances with all types of maize pneumatic drills used. Independent of the seeder model on which is mounted, it is able to obtain similar results highlighting an high operative versatility.
      PubDate: 2016-04-25T00:30:31.180102-05:
      DOI: 10.1002/ps.4302
  • Phytotoxicity of aminobisphosphonates targeting both
           δ1‐pyrroline‐5‐carboxylate reductase and glutamine
    • Abstract: BACKGROUND Dual‐target inhibitors may contribute to the management of herbicide‐resistant weeds and avoid or delay the selection of resistant biotypes. Some aminobisphosphonates inhibit the activity of both glutamine synthetase and δ1‐pyrroline‐5‐carboxylate (P5C) reductase in vitro, but the relevance of the latter in vivo has not been proven, yet. This study aimed at demonstrating that these compounds can block also proline synthesis in planta. RESULTS Two aminophosphonates, namely 3,5‐dichlorophenylamino‐methylenebisphosphonic acid and 3,5‐dibromophenylaminomethylenebis‐phosphonic acid (Br2PAMBPA), showed inverse effectiveness against the two partially purified target enzymes from rapeseed. The compounds showed equipotency in inhibiting the growth of rapeseed seedlings and cultured cells. The analysis of amino acid content in treated cells showed a strong reduction of glutamate and glutamate‐related amino acid pools, but a milder effect on free proline. In the case of Br2PAMBPA, toxic P5C levels accumulated in treated seedlings, proving that the inhibition of P5C reductase takes place in situ. CONCLUSIONS Phenyl‐substituted aminobisphosphonates may be regarded as true dual‐target inhibitors. Their use to develop new active principles for crop protection could consequently represent a tool to address the problem of target‐site resistance among weeds.
      PubDate: 2016-04-22T03:55:22.756387-05:
      DOI: 10.1002/ps.4299
  • Impact of Atrazine Prohibition on the Sustainability of Weed Management in
           Wisconsin Maize Production
    • Authors: Fengxia Dong; Paul D. Mitchell, Vince M. Davis, Ross Recker
      Abstract: BACKGROUND Controversy has surrounded atrazine due to its susceptibility to leaching and runoff, with regular calls for a ban or restrictions on its use. In the context of a decreasing trend in the percentage of US maize using no‐till since 2008, coinciding with the trend of glyphosate‐resistant weeds becoming problematic in the Midwestern US, we empirically examine how atrazine use restrictions impacted the diversity of weed management practices used by Wisconsin maize farmers. RESULTS Using survey data from farms inside and outside atrazine prohibition areas, we found that prohibiting atrazine did not directly impact tillage practices, but rather it increased adoption of herbicide‐resistant seed, which then increased adoption of conservation tillage systems. We also found that prohibiting atrazine and using herbicide‐resistant seed decreased the number of herbicide sites of action used. CONCLUSIONS The results indicate that prohibiting atrazine reduced the diversity of weed management practices, which increased the risk of herbicide resistance. Our concern is that a regulatory policy to address one issue (atrazine in groundwater) has induced farmer responses that increase problems with another issue (herbicide‐resistant weeds) that longer term will contribute to water quality problems from increased soil erosion and offset the initial benefits.
      PubDate: 2016-04-21T07:25:44.051588-05:
      DOI: 10.1002/ps.4298
  • The efficacy of Beauveria bassiana, jasmonic acid and chlorantraniliprole
    • Authors: Aneela Younas; Zaeema Khan, Waqas Wakil, Muhammad Shaaban, Sean Michael Prager
      Abstract: BCKGROUND A robust integrated pest management (IPM) program is needed to reduce the use of insecticides in controlling Helicoverpa armigera. Therefore, a two year field study was conducted to evaluate the use of alternative control measures (biochemical use) for H. armigera relative to exclusively use of chemical insecticides. The entomopathogenic fungi Beauveria bassiana, jasmonic acid and the insecticide chlorantraniliprole were each applied twice during the chickpea‐growing season. RESULTS All three applied materials (either alone or combined) significantly (p ≤ 0.05) reduced the larval population of H. armigera and pod infestation. Effects increased with time and the maximum difference was observed 7 days after the second application in each year. The lowest numbers of larvae per plant and pod infestation were in the B. bassiana 3.21 × 106 + chlorantraniliprole treatment in both 2009/2010 and 2010/2011 year. The reduction in the larval population and pod infestation increased chickpea yield and the highest yield in both seasons, and the maximum yield was obtained in the B. bassiana 3.21 × 106 + chlorantraniliprole treatment. The populations of natural enemies were highest in the jasmonic acid treatment. CONCLUSION The results suggest that B. bassiana, jasmonic acid and chlorantraniliprole may be useful components for H. armigera IPM strategy.
      PubDate: 2016-04-21T07:20:20.954756-05:
      DOI: 10.1002/ps.4297
  • Methoxyfenozide resistance of house fly, Musca domestica L. (Diptera:
           Muscidae): Cross‐resistance patterns, stability and associated
           fitness costs
    • Authors: Rizwan Mustafa Shah; Sarfraz Ali Shad, Naeem Abbas
      Abstract: BACKGROUND House fly, Musca domestica L., (Diptera: Muscidae) is an insect pest of public health and veterinary importance with ability to develop resistance to insecticides. Methoxyfenozide, an ecdysone agonist, is a bio‐rational insecticide being used for the management of various insect pests, including house flies. To design an effective resistance management strategy, life history traits based on laboratory observations were established for methoxyfenozide resistant (MXY‐SEL), unselected counterpart (UNSEL) and reciprocal cross strains of house fly. RESULTS The MXY‐SEL developed a resistance ratio of 160.99 after 30 generations of selection with methoxyfenozide compared to the UNSEL. The MXY‐SEL showed very low cross‐resistance to cyromazine, fipronil and chlorpyrifos and no cross‐resistance to spinosad and bifenthrin, when compared to the Methoxy‐Field population. Resistance to methoxyfenozide, cyromazine, fipronil, spinosad, chlorpyrifos, and bifenthrin was unstable in the MXY‐SEL. The MXY‐SEL had a reduced relative fitness (0.31), with lower hatchability, lower number of next generation larvae, lower intrinsic rate of natural increase, and lower biotic potential compared to the UNSEL. CONCLUSIONS Disadvantageous life history traits of the MXY‐SEL suggest that development of resistance to methoxyfenozide has considerable costs of fitness for this strain. Moreover, the unstable resistance to tested chemicals provides useful information to preserve the efficacy of these chemicals.
      PubDate: 2016-04-21T06:55:26.078672-05:
      DOI: 10.1002/ps.4296
  • Diet quality affects bait performance in German cockroaches (Dictyoptera:
    • Authors: Alexander E. Ko; Coby Schal, Jules Silverman
      Abstract: BACKGROUND Bait formulations are widely used to control German cockroach (Blattella germanica) populations. To perform optimally, these formulations must compete favorably with non‐toxic alternative foods present within the insect's habitat. We hypothesized that the nutritional history of cockroaches and their acceptance or avoidance of glucose would affect their food preference and thus bait efficacy. To test this hypothesis, we conducted a controlled laboratory experiment, first providing glucose‐accepting and glucose‐averse cockroaches nutritionally defined diets and then offering them identical diets containing the insecticide hydramethylnon as a bait proxy to evaluate the effect of diets of differing macronutrient composition on bait performance. RESULTS The interaction between diet composition and bait composition affected the survival of adult males as well as first instar nymphs exposed to excretions produced by these males. Survival analyses indicated different responses of glucose‐averse and glucose‐accepting insects, but generally, any combination of diet and bait that resulted in high diet intake and low bait intake decreased secondary kill. CONCLUSIONS This study represents a comprehensive examination of the effect of alternative foods on bait efficacy. We suggest that disparities between the nutritional quality of baits and the foods that are naturally available could profoundly impact the management of German cockroach infestations.
      PubDate: 2016-04-21T06:55:22.858708-05:
      DOI: 10.1002/ps.4295
  • The influence of time and distance traveled by bed bugs, Cimex
           lectularius, on permethrin uptake from treated mattress liners
    • Authors: Stephen A. Kells; Sabrina N. Hymel
      Abstract: Background Residual insecticides interrupt dispersal of bed bugs (Cimex lectularius, L.), but one of the issues encountered with residual applications is understanding the uptake of active residues by the insect. This study determined permethrin uptake by bed bugs walking on the ActiveGuard® Mattress Liner product, via a combination of video‐recording in arenas and gas chromatography analyses. Results The best model for estimating permethrin uptake utilized a covariance model (r2 = 0.469) with two factors: time of exposure (F1,55 = 2.44, P < 0.001) and distance traveled (F1,55 = 0.30 P = 0.0460). Bed bug permethrin‐uptake was 15.1 (95 % CI: 10.3 – 22.1) ng insect−1 within 1 min exposure; 21.0 (15.0, 31.0) ng insect−1 in 10 min; and, ≈42 (29.8, 60.6) ng insect−1 in ≥ 50 min exposure. Correcting for % recovery, these values would be would be increased by a factor of 1.21. Conclusion This permethrin‐treated fabric provides a surface from which bed bugs begin to rapidly absorb permethrin on contact and within the first 1 cm of travel. Variability in uptake was likely a result of grooming and thigmotaxis, and future work should use quantitative methods to study behaviors and formulations that increase exposure to the toxicant.
      PubDate: 2016-04-21T06:50:22.403982-05:
      DOI: 10.1002/ps.4294
  • Non‐target‐site glyphosate resistance in Conyza bonariensis is
           based on modified subcellular distribution of the herbicide
    • Authors: Ziv Kleinman; Baruch Rubin
      Abstract: BACKGROUND Conyza spp. was the first broadleaf weed reported to have evolved glyphosate resistance. Several mechanisms have been proposed for glyphosate resistance. In an effort to elucidate the mechanism of this resistance in Conyza bonariensis, possible target‐site and non‐target site mechanisms were investigated in glyphosate‐resistant (GR) C. bonariensis biotypes. RESULTS Using differential glyphosate applications and analyses of shikimate accumulation, we followed the herbicide effect in different plant organs and monitored the herbicide's apparent mobility. We found high shikimate levels in the roots and young leaves of GS plants regardless of the site of application; whereas in GR plants, shikimate accumulated mainly in treated young leaves. 14C‐glyphosate studies, however, revealed the expected source‐to‐sink translocation pattern in both GS and GR plants. Sequencing of the appropriate EPSPS DNA fragments of GR and glyphosate‐sensitive (GS) plants revealed no alteration at the Pro106 position. CONCLUSION These data support the hypothesis that the glyphosate resistance of our Conyza bonariensis GR biotypes is associated with altered subcellular distribution of glyphosate, which keeps the herbicide sequestered away from the EPSPS target site in the chloroplast.
      PubDate: 2016-04-21T06:45:23.281578-05:
      DOI: 10.1002/ps.4293
  • Landscape crop composition effects on cotton yield, Lygus hesperus
           densities, and pesticide use
    • Authors: Matthew H. Meisner; Tania Zaviezo, Jay A. Rosenheim
      Abstract: BACKGROUND Landscape crop composition surrounding agricultural fields is known to affect the density of crop pests, but quantifying these effects, as well as measuring how they translate to changes in yield, is difficult. Using a large dataset consisting of 1498 records of commercial cotton production in California between 1997 and 2008, we explored the relationship between landscape composition and cotton yield, the density of Lygus hesperus (a key cotton pest) at field‐level and within‐field spatial scales, and pesticide use. RESULTS We found that the crop composition immediately adjacent to a cotton field was associated with substantial differences in cotton yield, L. hesperus density, and pesticide use. Furthermore, crops that tended to be associated with increased L. hesperus density also tended to be associated with increased pesticide use and decreased cotton yield. CONCLUSION Our results suggest a possible mechanism by which landscape composition can affect cotton yield: by increasing the density of pests that in turn damage cotton plants. Our quantification of how surrounding crops affect pest densities, and in turn yield, in cotton fields, has significant impacts for cotton farmers who can use this information to help optimize crop selection and ranch layout.
      PubDate: 2016-04-10T22:35:23.986891-05:
      DOI: 10.1002/ps.4290
  • Effect of three safeners on sulfur assimilation and iron deficiency
           response in barley (Hordeum vulgare) plants
    • Authors: Maria Luce Bartucca; Silvia Celletti, Stefania Astolfi, Tanja Mimmo, Stefano Cesco, Ivan Panfili, Daniele Del Buono
      Abstract: BACKGROUND Safeners are agrochemicals used in agriculture to protect crop from herbicide injuries. They act by stimulating herbicide metabolism. Since graminaceous plants to cope with iron (Fe) deficiency activate sulfur (S) metabolism and release huge amounts of Fe chelating compounds (phytosiderophores – PSs), we investigated in barley plants (Hordeum vulgare, L.) grown in Fe‐deficiency the effects of three safeners on two enzymes of S assimilation, cysteine (Cys) and glutathione (GSH) contents, and PSs release. Finally, we monitored the root Fe content in plants treated with the most effective safener. RESULTS Generally, all the safeners activated S metabolism and increased Cys and GSH contents. In addition, the safened plants excreted higher levels of PSs. Being mefenpyr‐diethyl (Mef) the most effective in causing these effects, we assessed Fe concentration in Mef treated barley and we found higher Fe levels than those of untreated plants. CONCLUSION The three safeners differently, but specifically, activated S reductive metabolism, regulated Cys and GSH contents, PSs rate release and Fe content (Mef treated barley). The results of this research provide new indications on the biochemical and physiological mechanisms involved in the safening action.
      PubDate: 2016-04-08T13:09:21.844325-05:
      DOI: 10.1002/ps.4291
  • Postharvest impacts of rodents in Myanmar; how much rice do they eat and
    • Authors: Nyo Me Htwe; Grant R Singleton, Pyai Phyo Maw
      Abstract: BACKGROUND We undertook studies on postharvest losses by rodents in two townships in the Ayeyarwady delta, Myanmar. Farmers harvest their monsoon rice crop and then stack it on levee banks to await threshing 4–6 weeks later. After threshing and drying, paddy rice is stored in granaries. The amount of grain stored in burrows was collected 4 weeks after harvest by excavating burrows. In grain stores, we quantified weight of grain consumed by rodents for 3–6 months postharvest. RESULTS The dominant species in the field were Bandicota bengalensis and B. indica, whereas in grain stores the dominant species were Rattus rattus and R. exulans. The mean grain stored by rodents in burrows was 1.49 ± 0.9 kg/ burrow in 2013 and 1.41 ± 0.7 kg/ burrow in 2014. The mean loss of grain in granaries was higher in Daik U (14% in 2013, 4% in 2014) than Maubin (8.2% in 2013, 1.2% in 2014). The total amount of grain lost to rodents during piling and storing could feed households from 1.6‐4 months. CONCLUSION Postharvest losses to grain is a significant food security issue for smallholder farmers in Myanmar. Community rodent management and better rodent proofing of granaries are recommended to reduce rodent losses.
      PubDate: 2016-04-08T13:08:28.601908-05:
      DOI: 10.1002/ps.4292
  • Lures for Red Palm Weevil trapping systems: aggregation pheromone and
           synthetic kairomone
    • Abstract: BACKGROUND The optimization of the lure is essential for the implementation of trapping systems to control insect pests. In this work, the response of the red palm weevil (RPW), Rhynchophorus ferrugineus Olivier, to increasing emission rates of its aggregation pheromone (ferrugineol) and the efficacy of a convenient synthetic kairomone based on fermentation odors (ethyl acetate and ethanol) have been evaluated in different years and locations along the Mediterranean basin. RESULTS In general, although capture data and emission had noticeable variability among locations, significantly less RPW were captured in pyramidal Picusan® traps with the lowest ferrugineol emission rates tested (0.6‐3.8 mg/day−1). Captures increase rapidly with ferrugineol emission up to 4–5 mg day−1; then, higher emission rates did not improve nor decrease captures, up to the highest emission rate tested of 50.9 mg day−1. Thus, there is no evidence of an optimum release rate corresponding with a maximum of RPW catches. Traps baited with the synthetic kairomone (1:3 ethyl acetate/ethanol) captured from 1.4 to 2.2 times more total weevils than traps baited only with ferrugineol. Moreover, in most of the locations, the synthetic blend was at least as effective as the local co‐attractants used (plant material + molasses). CONCLUSIONS Ferrugineol emission rate can vary in a wide range without affecting significantly RPW response. Co‐attractants based on fermenting compounds, ethyl acetate and ethanol, are able to improve the attractant level of ferrugineol and could be employed to replace non‐standardized natural kairomones in RPW trapping systems after further optimization of their proportions and doses.
      PubDate: 2016-04-06T03:19:10.334186-05:
      DOI: 10.1002/ps.4289
  • Two compounds in bed bug feces are sufficient to elicit off‐host
           aggregation by bed bugs, Cimex lectularius
    • Authors: Joelle F. Olson; Leonard M. Ver Vers, Roger D. Moon, Stephen A. Kells
      Abstract: BACKGROUND After feeding, bed bugs aggregate in cracks and crevices near a host. Aggregation and arrestment are mediated by tactile and chemical stimuli associated with the bugs’ feces and exuviae. Volatiles derived from fecally stained filter papers were analyzed by SPME and evaluated using a multi‐choice behavioral assay to determine their impact on bed bug aggregation. In addition, crude fecal extracts were collected in methanol, analyzed by GC‐EAD and GC‐MS and evaluated in open‐air multiple choice behavioral assays. RESULTS An SPME method was used to detect (E)‐2‐hexenal and (E)‐2‐octenal in heated bed bug feces. The presence of these two volatile components did not affect aggregation. Analysis of the crude fecal extracts revealed several semi‐volatile nitrogenous compounds, a carboxylic acid, and a sulfur based compound. Adult antennae responded to compounds eluted from three regions of the crude extract using GC‐EAD. A combination of two compounds, dimethyl trisulfide (DMTS) and methyldiethanolamine (MDEA) resulted in aggregation responses equivalent to original crude extract. CONCLUSION Bed bug aggregation is mediated by semi‐volatile compounds derived from fecal extracts, and two compounds are sufficient to elicit aggregation. The two compounds identified here could be used to enhance the effectiveness of insecticidal applications or improve monitoring techniques.
      PubDate: 2016-04-06T02:52:55.892661-05:
      DOI: 10.1002/ps.4286
  • Knockdown of two trehalose‐6‐phosphate synthases severely
           affects chitin metabolism gene expression in the brown planthopper
           Nilaparvata lugens
    • Abstract: BACKGROUND RNA interference combined with digital gene expression (DGE) analysis can be used to study gene function. Trehalose‐6‐phosphate synthase (TPS) plays a key role in the synthesis of trehalose and insect development. RESULTS The DGE analysis revealed that the expression of 9 or 4 chitinase genes was decreased significantly 48 h after NLTPS1 and NLTPS2 knockdown by RNAi, respectively. Additionally, abnormal phenotypes were noted, and approximately 30% of insects died. HK and G6PI2 expression decreased significantly 72 h, whereas GFAT, GNPNA, and UAP expression increased significantly 72 h after two NLTPS genes RNAi knockdown. PGM1 expression decreased significantly after TPS2 knockdown, whereas PGM2 expression increased significantly and the expression of three CHS genes decreased 48 h after TPS1 knockdown. The mRNA expression of all of twelve chitin degradation genes decreased 48 h after NLTPS1 and NLTPS2 RNAi treatment, and Cht2, Cht3, Cht6, Cht7, Cht10, and ENGase levels remained significantly decreased up to 72 h after NLTPS1 and NLTPS2 RNAi knockdown. CONCLUSIONS These results demonstrate that silencing of TPS genes can lead to increased molting deformities and mortality rates due to the misregulation of genes involved in chitin metabolism, and TPS genes are potential pest control targets in the future.
      PubDate: 2016-04-06T02:51:47.088151-05:
      DOI: 10.1002/ps.4287
  • Evaluation of chromatic cue for trapping Bactrocera tau
    • Authors: Lei Li; Huabo Ma, Liming Niu, Dongyin Han, Fangping Zhang, Junyu Chen, Yueguan Fu
      Abstract: BACKGROUND Trapping technology based on chromatic cues is an important strategy in controlling Tephritidae (fruit flies). The objectives of this present study were to evaluate the preference of Bactrocera tau to different chromatic cues and to explore an easy method to print and reproduce color paper. RESULTS Chromatic cues significantly affected the preference of adult B. tau. The wavelengths in the range of 515 to 604 nm were the suitable wavelengths for trapping B. tau. Different day‐old B. tau had different color preferences. Virtual wavelengths of 595 (yellow) and 568 nm (yellowish green) were the optimum wavelengths for trapping 5‐day‐old to 7‐day‐old B. tau and 30‐day‐old to 32‐day‐old B. tau, respectively. The trap type and height significantly influenced the attraction efficiency of B. tau. The number of B. tau on color traps hung perpendicular to plant rows were not significantly higher than those hung parallel to plant rows. CONCLUSION The quantization of color on the basis of Bruton's wavelength to RGB function can be served as an alternative method to print and reproduce the color papers, but a corrected equation should be established between the theoretical wavelength and actual wavelength of color papers. Results show that a compound paper colored yellow (595 nm) and yellowish green (568 nm) installed at 60 and 90 cm in height above the ground show the maximum effect for trapping B. tau.
      PubDate: 2016-04-06T02:49:50.114541-05:
      DOI: 10.1002/ps.4288
  • Trypsin inhibitor from Leucaena leucocephala seeds delays and disrupts the
           development of Aedes aegypti, a multiple disease vector
    • Abstract: BACKGROUND Nowadays Aedes aegypti mosquito represents a serious issue in public health due to the large outbreaks of the arboviral diseases Zika, Dengue, Chikungunya and Yellow fever. This holometabolous insect has midgut digestive enzymes which are trypsin and chymotrypsin‐like proteins. Protease inhibitors are able to bind to proteolytic enzymes and promote a blockage in digestion and nutrition leading to death. Thus, we investigated the effect of trypsin inhibitor of Leucaena leucocephala (LTI) seeds upon egg hatching, larval development and digestive midgut proteases. RESULTS LTI was obtained by TCA‐precipitation followed by a single chromatography step on anhydrous trypsin sepharose. SDS‐PAGE showed a single protein band with molecular mass near 20 kDa. After exposure of Ae. aegypti egg to LTI (0.3 mg.mL−1), egg hatching was reduced (50%). LTI did not show acute toxicity on newly hatched larvae incubated under the same conditions, but after ten days of exposure a high mortality rate (86%) was observed and the surviving larvae had a 25% delay in development. LTI was able to inhibit in vitro the midgut enzymatic activity (70%) and when larvae were incubated with LTI solution we observed an inhibition of 56%. CONCLUSIONS LTI is a promising new tool to control critical points of Ae. aegypti development.
      PubDate: 2016-04-04T06:29:03.104057-05:
      DOI: 10.1002/ps.4284
  • The mononuclear NiII complex
           protects tomato from Verticillium dahliae by inhibiting the fungal growth
           and activating plant defenses
    • Authors: Hanane Zine; Lalla Aicha Rifai, Tayeb Koussa, Fouad Bentiss, Salaheddine Guesmi, Abdelhakim Laachir, Kacem Makroum, Malika Belfaiza, Mohamed Faize
      Abstract: BACKGROUND The antifungal proprieties of the nickel complex bis(azido‐κN)bis[2,5‐bis(pyridin‐2‐yl)‐1,3,4‐thiadiazole‐κ2N2,N3]nickel(II) (noted NiL2(N3)2) and its parental ligand 2,5‐bis(pyridin‐2‐yl)‐1,3,4‐thiadiazole (L) were examined to evaluate their ability to protect tomato plants against Verticillium dahliae. Our main objectives were to determine their effects on the in vitro growth of the pathogen, and their aptitude on controlling verticillium wilt and activating plant defense responses in the greenhouse. RESULTS NiL2(N3)2 exhibited in vitro an elevated inhibition of radial growth of three strains of the pathogen. According to the strain, the EC50 values ranged from 10 to 29 µg ml−1 for NiL2(N3)2. In the greenhouse, it induced an elevated protection against V. dahliae when it was applied twice as foliar sprays at 50 µg ml−1. It reduced leaf alteration index by 85% and vessel browning by 96%. In addition, its protective ability was associated with the accumulation of H2O2, and the activation of total phenolic content as well as potentiation of the activity of peroxidase and polyphenol oxidase. CONCLUSION These results demonstrated that coordination of ligand with Ni associated to the azide as a co‐ligand resulted in the improvement of its biological activity by both inhibiting the growth of the V. dahliae and activating plant defense responses.
      PubDate: 2016-04-04T06:27:38.017174-05:
      DOI: 10.1002/ps.4285
  • Impact of Bacillus cereus NRKT on grape ripe rot disease through
           resveratrol synthesis in berry skin
    • Authors: Takanori Aoki; Yoshinao Aoki, Shiho Ishiai, Misa Otoguro, Shunji Suzuki
      Abstract: BACKGROUND Vine growers are faced with the difficult problem of how to control grape ripe rot disease in vineyards because of fear of accumulation of pesticide residues on grape berries near harvest. Biological control is an alternative non‐hazardous technique to control the diseases. RESULTS Application of resveratrol‐synthesis‐promoting bacterium, Bacillus cereus strain NRKT, decreased the incidence of grape ripe rot disease caused by Colletotrichum gloeosporioides in a vineyard. The application of NRKT to berry bunches upregulated the gene expression of stilbene synthase, a key enzyme for resveratrol synthesis in berry skins, thereby promoting resveratrol synthesis in berry skins. CONCLUSION The potential use of NRKT in vineyards is expected to contribute to the increase of resveratrol content in berry skins, thereby protecting grape berries against fungal diseases.
      PubDate: 2016-04-01T00:12:10.405601-05:
      DOI: 10.1002/ps.4283
  • Migration by seed dispersal of ACCase inhibitor resistant Avena fatua in
           Northwestern Mexico
    • Abstract: BACKGROUND Biotypes of Avena fatua resistant to ACCase‐inhibiting herbicides have been reported in the States of Baja California (BC) and Sonora (SON), Mexico. We hypothesized that resistant biotypes present in SON (Valle de Hermosillo and Valle del Yaqui) are derived from a resistant population from BC (Valle de Mexicali) via gene flow, due to the transport and exchange of contaminated wheat seed. This study aimed to determine: 1) the resistance of A. fatua to ACCase‐inhibiting herbicides in populations from BC and SON, 2) the mutation at the site of action and 3) the genetic structure and gene flow among populations. RESULTS DNA sequencing showed that all biotypes shared the same mutation (Leu x Ile at codon 1781). Microsatellites showed evidence of a genetic bottleneck in SON, and spatial analysis of molecular variance grouped one biotype from the Valle de Mexicali with two biotypes from the Valle de Hermosillo. Migration analysis suggested gene flow from the Valle de Mexicali to the Valle de Hermosillo, but not to the Valle del Yaqui. CONCLUSIONS The presence of resistant biotypes of Avena fatua in the Valle de Hermosillo, SON are likely derived from seeds from BC, possibly through the transport of contaminated wheat seeds.
      PubDate: 2016-04-01T00:11:55.39262-05:0
      DOI: 10.1002/ps.4282
  • Distinguishing between weedy Amaranthus species based on intron one
           sequences from the 5‐enolpyruvylshikimate‐3‐phosphate
           synthase (EPSPS) gene
    • Authors: Alice A. Wright; William T. Molin, Vijay K. Nandula
      Abstract: BACKGROUND Hybridization between Amaranthus species and the potential for herbicide resistance to be transferred by hybridization are of growing concern in the weed science community. Early detection of evolved herbicide resistance and hybrids expressing resistance to single or multiple herbicides is important to develop an effective control strategy. RESULTS A PCR test was developed to quickly identify weedy amaranths and any hybrids. The sequences of intron one for the 5‐enolpyruvylshikimate‐3‐phosphate synthase (EPSPS; EC gene were determined for Amaranthus palmeri, A. retroflexus, A. blitoides, A. viridis, A. tuberculatus, and A. hybridus. These sequences were aligned and primers were developed in areas where the sequence differed between species. Species specific primers and cycle conditions were successfully developed. These primers produce a single robust band only for the species for which they were designed. CONCLUSION The PCR techniques described here allow identification of a weedy amaranth or suspect hybrid in a few hours. Using a similar target, it may be possible to design similar, simple PCR tests to identify even more difficult to distinguish weed species or weeds prone to interspecific hybridization.
      PubDate: 2016-03-23T01:30:50.477582-05:
      DOI: 10.1002/ps.4280
  • Evaluation of Spray Application Methods for Navel Orangeworm Control in
    • Authors: James C. Markle; Franz J. Niederholzer, Frank G. Zalom
      Abstract: BACKGROUND Gear Up, Throttle Down (GUTD) and Inward Only strategies represent potential alternatives to conventional airblast applications to reduce spray drift. This study evaluates Inward Only and a modified version of GUTD in almonds, the largest U.S. tree crop, at the recommended hull split treatment timing for control of navel orangeworm (NOW), the key almond insect pest. RESULTS Conventional treatment produced the most drift (15.6% of total bifenthrin load) while the GUTD and Inward Only treatments produced only 7.6% and 9.7%, respectively. For all methods 92‐94% of the drift was found in the first 15.2 m downwind of the orchard. NOW control was lower for the Inward Only treatment compared with the GUTD and Conventional treatments. NOW control was consistently lower at the 4.88 m height relative to 2.44 m in all treatments, reflecting the reduced deposition higher in the tree canopy recorded in deposition samples. CONCLUSION While Inward Only treatments reduced spray drift relative to the Conventional application method, poorer control of NOW, the key insect pest of almonds, in the Inward Only treatment would likely limit its voluntary use by growers. However, GUTD holds promise for use at the hull split treatment timing to address spray drift.
      PubDate: 2016-03-22T03:50:23.073853-05:
      DOI: 10.1002/ps.4279
  • Accurate prediction of black‐rot epidemics in vineyards using a
           weather‐driven disease model
    • Abstract: Background Grapevine black‐rot caused by Guignardia bidwellii is a serious threat in vineyards, especially in areas with cool and humid springs. A mechanistic, weather‐driven model was recently developed for the detailed prediction of black‐rot epidemics. The aim of this work was the evaluation of the model by comparison with observed disease development in leaves and clusters in a vineyard in north Italy from 2013 to 2015. Results The model accurately predicted disease onset. The probability of predicting new infections that did not occur (i.e., unjustified alarms) was ≤ 0.180, while the probability of missing actual infections was 0.175 for leaves and 0.263 for clusters. In 78% of these false negative predictions, the difference between expected and actual disease onset was ± 2 days; therefore, only one infection period was actually missed by the model. The model slightly overestimated disease severity (mainly on leaves) when the observed disease severity was >0.6. Conclusions The model was highly accurate and robust in predicting the infection periods and dynamics of black‐rot epidemics. The model can be used for scheduling fungicide sprays in vineyards.
      PubDate: 2016-03-21T02:45:25.232311-05:
      DOI: 10.1002/ps.4277
  • Phenotypical and biochemical characterization of resistance for parasitic
           weed (Orobanche foetida Poir.) in radiation mutagenized mutants of
    • Authors: Ines Brahmi; Yassine Mabrouk, Guillaume Brun, Philippe Delavault, Omrane Belhadj, Philippe Simier
      Abstract: BACKGROUND Some radiation mutagenized chickpea mutants potentially resistant to the broomrape, Orobanche foetida Poir., were selected through field trials. The objectives of this work were to confirm resistance under artificial infestation, in pots and mini‐rhizotron systems, and to determine the developmental stages of broomrape affected by resistance and the relevant resistance mechanisms induced by radiation mutagenesis. RESULTS Among thirty mutants tested for resistance to O. foetida, five shared strong resistance in both pot experiments and mini‐rhizotrons systems. Resistance was not complete but the few individuals which escaped resistance displayed high disorders of shoot development. Results demonstrated a 2–3 fold decrease in stimulatory activity of root exudates towards broomrape seed germination in resistant mutants in comparison to non‐irradiated control plants and susceptible mutants. Resistance was associated to an induction of broomrape necrosis early during infection. When infested, most of resistant mutants shared enhanced levels in soluble phenolic contents, phenylalanine ammonia lyase activity, guaiacol peroxidase activity, polyphenol oxidase activity, in addition to glutathione and notably ascorbate peroxidase gene expression in roots. CONCLUSION Results confirmed enhanced resistance in chickpea radiation mutagenized mutants, and demonstrated resistance is rested on alteration of root exudation, presumed cell wall reinforcement and change in root oxidative status in response to infection.
      PubDate: 2016-03-21T02:45:22.563375-05:
      DOI: 10.1002/ps.4278
  • Genetic variation in target‐site resistance to pyrethroids and
           pirimicarb in Tunisian populations of the peach potato aphid, Myzus
           persicae (Sulzer) (Hemiptera: Aphididae)
    • Abstract: BACKGROUND We used molecular assays to diagnose resistance to pyrethroids and pirimicarb in samples of Myzus persicae from field crops or an insect suction trap in Tunisia. Genotypes for resistance loci were related to ones for polymorphic microsatellite loci in order to investigate breeding systems, patterns of genetic diversity and to inform resistance management tactics. RESULTS The kdr mutation L1014F conferring pyrethroid resistance was found in all samples. The M918T s‐kdr mutation also occurred in most samples, but only in conjunction with kdr. We discovered a previously unreported genotype heterozygous for L1014F but homozygous for M918T. Samples with modified acetylcholinesterase (MACE) conferring resistance to pirimicarb were less common but widespread. 16% of samples contained both the kdr and MACE mutations. Many unique microsatellite genotypes were found, suggesting that M. persicae is holocyclic in Tunisia. There were no consistent associations between resistance and microsatellite markers. CONCLUSION This first study of insecticide resistance in M. persicae in North Africa showed genetic variation in insecticide resistance within microsatellite multilocus genotypes (MLGMs) and the same resistance mechanisms to be present in different MLGMs. This contrasts with variation in northern Europe where M. persicae is fully anholocyclic. Implications for selection and control strategies are discussed.
      PubDate: 2016-03-16T03:16:28.066508-05:
      DOI: 10.1002/ps.4276
  • Increasing social welfare by taxing pesticide externalities in the Indian
           cotton sector
    • Authors: Livia Rasche; Alexander Dietl, Nikolinka Shakhramanyan, Divya Pandey, Uwe A. Schneider
      Abstract: Background Pesticide use in the Indian cotton industry has decreased with the introduction of Bt cotton, but rates are still high in comparison to other countries. The adoption of alternative strategies, such as integrated pest management, has been slow, even though benefits are potentially high, more so if the full costs of the external effects of the technologies are taken into account. In order to estimate true societal benefits of different strategies, we compare their external costs and economic performance under external cost taxation, using a state of the art partial equilibrium model of the Indian agricultural sector. Results Pesticide externalities lower social welfare in the Indian cotton sector by USD 400–2200 million, depending on the technologies employed. A full internalization decreases producer revenues by 100 USD/ha if only Bt cotton is used, and by 30 USD/ha if IPM is another option. Consumers don't start to lose surplus until 20‐70% are internalized, and losses are smaller if all technologies are available. Conclusions External pesticide costs can be internalized partially without substantially impacting consumer surplus while still increasing social welfare, but producers need to have access to and the knowledge to employ all available cotton production technologies to minimize losses.
      PubDate: 2016-03-15T06:41:54.747232-05:
      DOI: 10.1002/ps.4275
  • Frequency of Cry1F Resistance Alleles in Spodoptera frugiperda
           (Lepidoptera: Noctuidae) in Brazil
    • Authors: Juliano R Farias; David A. Andow, Renato J Horikoshi, Daniel Bernardi, Rebeca da S Ribeiro, Antonio R B do Nascimento, Antonio C dos Santos, Celso Omoto
      Abstract: BACKGROUND The frequency of resistance alleles is a major factor influencing the rate of resistance evolution. Here, we adapted the F2 screen procedure for Spodoptera frugiperda (J.E. Smith) with a discriminating concentration assay, and extended associated statistical methods to estimate the frequency of resistance to Cry1F protein in S. frugiperda in Brazil when resistance was not rare. RESULTS We show that F2 screen is efficient even when resistance frequency is 0.250. It was possible to screen 517 isoparental lines from 12 populations sampled in five states of Brazil during the first half of 2012. Western Bahia had the highest allele frequency of Cry1F resistance, 0.192, with a 95% confidence interval (CI) between 0.163 and 0.220. All other states had a similar and lower frequency varying from 0.042 in Paraná to 0.080 in Mato Grosso do Sul. CONCLUSION The high frequency in western Bahia may be related to year‐round availability of maize, the high population density of S. frugiperda, the lack of refuges, and the high adoption rate of Cry1F maize. Cry1F resistance alleles were not rare and occurred at frequencies that have already compromised the useful life of TC1507 maize in western Bahia.
      PubDate: 2016-03-15T05:51:16.334391-05:
      DOI: 10.1002/ps.4274
  • Simplified strigolactams as potent analogues of strigolactones for the
           seed germination induction of Orobanche cumana Wallr
    • Abstract: Background Strigolactones play an important role in the rhizosphere as signaling molecules stimulating the seed germination of parasitic weed seeds and hyphal branching of arbuscular micorrhiza and also act as hormones in plant roots and shoots. Strigolactone derivatives e.g. strigolactams could be used as suicidal germination inducers in the absence of a host crop for the decontamination of land infested with parasitic weed seeds. Results We report the stereoselective synthesis of novel strigolactams together with some of their critical physicochemical properties such as water solubility, hydrolytic stability, as well as their short soil persistence. In addition, we show that such strigolactams are potent germination stimulants of O. cumana parasitic weed seeds and do not affect the seed germination and the root growth of sunflower. Conclusions The novel strigolactam derivatives described here compare favorably with the corresponding GR‐28 strigolactones in term of biological activity and physicochemical properties. However, we believe strigolactone‐ and strigolactam‐ derivatives require further structural optimization to improve their soil persistence to demonstrate a potential for agronomical applications.
      PubDate: 2016-03-04T03:44:40.053989-05:
      DOI: 10.1002/ps.4268
  • Combining electrostatic powder with an insecticide: effect on stored
           product beetles and on the commodity
    • Authors: Christos G Athanassiou; Thomas N Vassilakos, Anna C. Dutton, Nicholas Jessop, David Sherwood, Garry Pease, Andreja Brglez, Clare Storm, Stanislav Trdan
      Abstract: BACKROUND The opportunity to reduce the amount of pirimiphos‐methyl applied to grain by formulating it in an electrostatic powder was investigated. The insecticidal efficacy of pirimiphos‐methyl in EC formulation or formulated using electrostatic powder (EP) as an inert carrier was investigated against; Sitophilus oryzae (L.), Oryzaephilus surinamensis (L.), Rhyzopertha dominica (F.) and Tribolium confusum Jacquelin du Val. Furthermore, the adhesive properties of EP, to rice, corn and wheat, together with the effect on bulk density and bread and pasta making properties were investigated. RESULTS The results showed that pirimiphos‐methyl formulated with EP provided better efficacy against adults when compared to EC formulation for O. surinamensis and T. confusum, but there was no difference for R. dominica. Progeny production was consistently lower in grain treated with the EP formulation than the EC. The adherence tests showed that EP remained on the kernels greater on hard wheat than on maize or rice. In most commodities EP did not alter the bulk density. Finally, the addition of EP did not affect flour and bread making properties, nor the pasta making properties. CONCLUSIONS The results of the present study suggest that an EP could be used to reduce the amount of pirimiphos‐methyl applied to grain for effective pest control with no detrimental effects on grain quality.
      PubDate: 2016-02-11T01:27:40.889661-05:
      DOI: 10.1002/ps.4255
  • Issue Information ‐ Aims and Scope
    • Pages: 1627 - 1627
      PubDate: 2016-07-25T04:16:56.544063-05:
      DOI: 10.1002/ps.4131
  • Issue Information ‐ Info Page
    • Pages: 1628 - 1628
      PubDate: 2016-07-25T04:16:53.786644-05:
      DOI: 10.1002/ps.4132
  • Issue Information ‐ ToC
    • Pages: 1629 - 1630
      PubDate: 2016-07-25T04:16:56.133829-05:
      DOI: 10.1002/ps.4133
  • Cross‐resistance to prosulfocarb + S‐metolachlor and
           pyroxasulfone selected by either herbicide in Lolium rigidum
    • Authors: Roberto Busi; Stephen B Powles
      Pages: 1664 - 1672
      Abstract: BACKGROUND Weeds can be a greater constraint to crop production than animal pests and pathogens. Pre‐emergence herbicides are crucial in many cropping systems to control weeds that have evolved resistance to selective post‐emergence herbicides. In this study we assessed the potential to evolve resistance to the pre‐emergence herbicides prosulfocarb + S‐metolachlor or pyroxasulfone in 50 individual field Lolium rigidum populations collected in a random survey in Western Australia prior to commercialisation of these pre‐emergence herbicides. RESULTS This study shows for the first time that in randomly collected L. rigidum field populations the selection with either prosulfocarb + S‐metolachlor or pyroxasulfone can result in concomitant evolution of resistance to both prosulfocarb + S‐metolachlor and pyroxasulfone after three generations. CONCLUSIONS In the major weed L. rigidum, traits conferring resistance to new herbicides can be present before herbicide commercialisation. Proactive and multidisciplinary research (evolutionary ecology, modelling and molecular biology) is required to detect and analyse resistant populations before they can appear in the field. Several studies show that evolved cross‐resistance in weeds is complex and often unpredictable. Thus, long‐term management of cross‐resistant weeds must be achieved through heterogeneity of selection by effective chemical, cultural and physical weed control strategies that can delay herbicide resistance evolution. © 2016 Society of Chemical Industry
      PubDate: 2016-03-21T04:45:56.40708-05:0
      DOI: 10.1002/ps.4253
  • A psbA mutation (Val219 to Ile) causes resistance to propanil and
           increased susceptibility to bentazon in Cyperus difformis
    • Pages: 1673 - 1680
      Abstract: BACKGROUND Propanil‐resistant (R) Cyperus difformis populations were recently confirmed in California rice fields. To date, propanil resistance in other weed species has been associated with enhanced aryl acylamidase (AAA)‐mediated propanil conversion into 3,4‐dichloroaniline. Our objectives were to determine the level of propanil resistance and cross‐resistance to other PSII inhibitors in C. difformis lines, and to elucidate the mechanism of propanil resistance. RESULTS The propanil‐R line had a 14‐fold propanil resistance and increased resistance to bromoxynil, diuron and metribuzin, but not to atrazine. The R line, however, displayed a fourfold increased susceptibility to bentazon. Interestingly, susceptible (S) plants accumulated more 3,4‐dichloroaniline and were more injured by propanil and carbaryl (AAA‐inhibitor) applications than R plants, suggesting that propanil metabolism is not the resistance mechanism. psbA gene sequence analysis indicated a valine‐219–isoleucine (Val219Ile) amino acid exchange in the propanil‐R chloroplast D1 protein. CONCLUSION The D1 Val219Ile modification in C. difformis causes resistance to propanil, diuron, metribuzin and bromoxynil but increased susceptibility to bentazon, suggesting that the Val219 residue participates in binding of these herbicides. This is the first report of a higher plant exhibiting target‐site propanil resistance. Tank mixing of bentazon and propanil, where permitted, can control both propanil‐R and propanil‐S C. difformis and prevent the spread of the resistant phenotype. © 2016 Society of Chemical Industry
      PubDate: 2016-04-06T02:11:27.78165-05:0
      DOI: 10.1002/ps.4267
  • Biochemical basis of alphamethrin resistance in different life stages of
           Anopheles stephensi strains of Bangalore, India
    • Authors: Thiruvaipati PN Hariprasad; Nadikere J Shetty
      Pages: 1689 - 1701
      Abstract: BACKGROUND Anopheles stephensi is an important urban malaria vector in the Indian subcontinent. Extensive application of insecticides evokes microevolution, which results in resistance that can be traced back to their genotypes. In this study, resistant and susceptible strains of An. stephensi for alphamethrin were selected by selective inbreeding for 27 and ten generations respectively. The biochemical basis of resistance in all the life stages was investigated. Quantitative assays were performed for proteins (total and soluble), esterases (α, β and acetylcholine) and phosphatases (acid and alkaline) by spectrophotometry, and qualitative assays for the enzymes by native polyacrylamide gel electrophoresis. RESULTS The enzyme quantities significantly varied in all life stages of the resistant strain as compared with the susceptible ones. Qualitative studies showed seven isoforms for α‐ and β‐esterases, three each for acetylcholinesterase and alkaline phosphatase and two for acid phosphatase. Exclusive bands were found in the resistant strain, such as α‐Est 1 and β‐Est 1 in eggs and larvae, β‐Est 3 in adult males, β‐Est 2 in adult females and AlkP 1, AlkP 2 and AlkP 3 in adult females, larvae and adult males respectively. CONCLUSION Variations in the quantity and specific enzyme isoforms play a key role in the development of alphamethrin resistance in An. stephensi. © 2015 Society of Chemical Industry
      PubDate: 2016-01-04T08:21:49.769447-05:
      DOI: 10.1002/ps.4194
  • Efficacy of entomopathogenic nematodes against larvae of Tuta absoluta in
           the laboratory
    • Authors: Veerle M Van Damme; Bert KEG Beck, Els Berckmoes, Rob Moerkens, Lieve Wittemans, Raf De Vis, David Nuyttens, Hans F Casteels, Martine Maes, Luc Tirry, Patrick De Clercq
      Pages: 1702 - 1709
      Abstract: BACKGROUND Previous studies have indicated the control potential of entomopathogenic nematodes (EPNs) against Tuta absoluta. Here, the potential of Steinernema feltiae, S. carpocapsae and Heterorhabditis bacteriophora is studied when applied against larvae of T. absoluta inside leaf mines in tomato leaf discs by means of an automated spray boom. RESULTS The studied EPN species were effective against all four larval instars of T. absoluta but caused higher mortality in the later instars (e.g. fourth instar: 77.1–97.4% mortality) than in the first instars (36.8–60.0% mortality). Overall, S. feltiae and S. carpocapsae yielded better results than H. bacteriophora. Steinernema carpocapsae and H. bacteriophora performed better at 25 °C (causing 55.3 and 97.4% mortality respectively) than at 18 °C (causing 12.5 and 34.2% mortality respectively), whereas S. feltiae caused 100% mortality at both temperatures. Under optimal spraying conditions and with the use of Addit and Silwet L‐77 adjuvants, a reduced dosage of 6.8 infective juveniles (IJs) cm−2 yielded equally good control as a recommended dosage of 27.3 IJs cm−2. CONCLUSION Under laboratory conditions, S. feltiae and S. carpocapsae showed good potential against the larvae of T. absoluta inside tomato leaf mines. Results need to be confirmed in greenhouse experiments. © 2015 Society of Chemical Industry
      PubDate: 2016-01-04T08:42:59.779197-05:
      DOI: 10.1002/ps.4195
  • Apoptotic activity and gene responses in Drosophila melanogaster S2 cells,
           induced by azadirachtin A
    • Authors: Lin Xu; Sheng Li, Xueqin Ran, Chang Liu, Rutao Lin, Jiafu Wang
      Pages: 1710 - 1717
      Abstract: BACKGROUND Azadirachtin has been used as an antifeedant and growth disruption agent for many insect species. Previous investigations have reported the apoptotic effects of azadirachtin on some insect cells, but the molecular mechanisms are still not clear. This study investigated the underlying molecular mechanisms for the apoptotic effects induced by azadirachtin on Drosophila melanogaster S2 cells in vitro. RESULTS The results of the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2H‐tetrazolium bromide assay demonstrated that azadirachtin exhibited significant cytotoxicity to S2 cells in a time‐ and dose‐dependent manner. The changes in cellular morphology and the DNA fragmentation demonstrated that azadirachtin induced remarkable apoptosis of S2 cells. Expression levels of 276 genes were found to be significantly changed in S2 cells after exposure to azadirachtin, as detected by Drosophila genome array. Among these genes, calmodulin (CaM) was the most highly upregulated gene. Azadirachtin was further demonstrated to trigger intracellular Ca2+ release in S2 cells. The genes related to the apoptosis pathway, determined from chip data, were validated by the real‐time quantitative polymerase chain reaction method. CONCLUSION The results showed that azadirachtin‐mediated intracellular Ca2+ release was the primary event that triggered apoptosis in Drosophila S2 cells through both pathways of the Ca2+‐CaM and EcR/Usp signalling cascade. © 2015 Society of Chemical Industry
      PubDate: 2016-01-04T11:49:37.344362-05:
      DOI: 10.1002/ps.4198
  • Efficacy of a Juncus effusus extract on grapevine and apple plants against
           Plasmopara viticola and Venturia inaequalis, and identification of the
           major active constituent
    • Pages: 1718 - 1726
      Abstract: BACKGROUND There is growing demand to replace chemical pesticides with alternatives owing to concerns related to impacts on human health and the environment. Plant‐derived plant protection products could provide sustainable and environmentally friendly alternatives to chemical products. The aim of this study was to identify plant and fungal extracts with so far unknown activity against important plant pathogens by in vitro screening of a library of more than 3000 extracts. RESULTS Several plant extracts with promising in vitro fungicidal activity (MIC100 ≤ 50 µg mL−1) towards one or several of the investigated pathogens (Venturia ineaqualis, Phytophthora infestans, Plasmopara viticola) were identified by the screening. One of the hits, an ethyl acetate extract of Juncus effusus L. medulla, was further investigated, and dehydroeffusol (DHEF) was identified as its main active constituent. On susceptible grapevine and apple seedlings, efficacies of up to 100% were reached with the extract (EC50 123 or 156 µg mL−1) and with DHEF (EC50 18 or 21 µg mL−1) against P. viticola and V. inaequalis respectively. CONCLUSIONS Our results demonstrate that plants can provide promising alternatives for integrated and organic farming. J. effusus shows high efficacy at low concentrations and, as an abundant perennial species, is an interesting candidate for the development of a novel plant protection product. © 2015 Society of Chemical Industry
      PubDate: 2016-01-22T07:44:59.667469-05:
      DOI: 10.1002/ps.4199
  • Field‐evolved resistance to Cry1Ab maize by Spodoptera frugiperda in
    • Authors: Celso Omoto; Oderlei Bernardi, Eloisa Salmeron, Rodrigo J Sorgatto, Patrick M Dourado, Augusto Crivellari, Renato A Carvalho, Alan Willse, Samuel Martinelli, Graham P Head
      Pages: 1727 - 1736
      Abstract: BACKGROUND The first Bt maize in Brazil was launched in 2008 and contained the MON 810 event, which expresses Cry1Ab protein. Although the Cry1Ab dose in MON 810 is not high against fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), MON 810 provided commercial levels of control. To support insect resistance management in Brazil, the baseline and ongoing susceptibility of FAW was examined using protein bioassays, and the level of control and life history parameters of FAW were evaluated on MON 810 maize. RESULTS Baseline diet overlay assays with Cry1Ab (16 µg cm−2) caused 76.3% mortality to field FAW populations sampled in 2009. Moderate mortality (48.8%) and significant growth inhibition (88.4%) were verified in leaf‐disc bioassays. In greenhouse trials, MON 810 had significantly less damage than non‐Bt maize. The surviving FAW larvae on MON 810 (22.4%) had a 5.5 day increase in life cycle time and a 24% reduction in population growth rate. Resistance monitoring (2010–2015) showed a significant reduction in Cry1Ab susceptibility of FAW over time. Additionally, a significant reduction in the field efficacy of MON 810 maize against FAW was observed in different regions from crop season 2009 to 2013. CONCLUSIONS The decrease in susceptibility to Cry1Ab was expected, but the specific contributions to this resistance by MON 810 maize cannot be distinguished from cross‐resistance to Cry1Ab caused by exposure to Cry1F maize. Technologies combining multiple novel insecticidal traits with no cross‐resistance to the current Cry1 proteins and high activity against the same target pests should be pursued in Brazil and similar environments. © 2015 Society of Chemical Industry
      PubDate: 2016-01-04T08:21:52.021763-05:
      DOI: 10.1002/ps.4201
  • Monitoring the effects of thiamethoxam applied as a seed treatment to
           winter oilseed rape on the development of bumblebee (Bombus terrestris)
    • Authors: Helen Thompson; Mike Coulson, Natalie Ruddle, Selwyn Wilkins, Paul Harrington, Sarah Harkin
      Pages: 1737 - 1742
      Abstract: Background The development of bumblebee (Bombus terrestris audax) colonies that had foraged for 5 weeks on flowering winter oilseed rape grown from seed treated with thiamethoxam (as Cruiser OSR) was assessed (two control, one treated field). Colony development was evaluated by monitoring the colony mass, forager activity was assessed, both at the hive and within the crop, and the contribution of oilseed rape to the pollen stored within the colony was analysed. Results Pollen collected from the treated crop contained residues of 1.0 µg thiamethoxam kg−1 and 3.0 µg CGA322704 (metabolite likely equivalent to clothiandin) kg−1, and nectar contained residues of 1.8 µg thiamethoxam kg−1 and no metabolite. No residues of thiamethoxam or CGA322704 were detected in samples from the control fields. Up to 93% of bumblebee collected pollen sampled from within the colonies originated from oilseed rape, and B. terrestris were observed actively foraging on all the fields. Colonies on all three fields showed similar rates of mass gain during the exposure phase and comparable production of gynes and drones. Conclusions B. terrestris colonies placed adjacent to a field of flowering oilseed rape grown from thiamethoxam‐treated seed developed at a comparable rate with colonies placed adjacent to oilseed rape grown from untreated seed. © 2015 Society of Chemical Industry
      PubDate: 2016-01-25T08:15:55.787157-05:
      DOI: 10.1002/ps.4202
  • Molecular characterisation of the vitellogenin gene (AlVg) and its
           expression after Apolygus lucorum had fed on different hosts
    • Authors: Yang Sun; Liubin Xiao, Guangchun Cao, Yongjun Zhang, Yingfang Xiao, Guangchun Xu, Jing Zhao, Yongan Tan, Lixin Bai
      Pages: 1743 - 1751
      Abstract: BACKGROUND The polyphagous pest Apolygus lucorum is now the dominant pest of Bacillus thuringiensis (Bt) cotton in China. In this study, the transcriptional and translational profiles of AlVg influenced by different hosts were identified, and then the correlations between AlVg gene or AlVg protein expression and key population proliferation parameters of A. lucorum were further clarified. RESULTS AlVg or AlVg expression can be significantly regulated by different host nutrients (P < 0.05). AlVg or AlVg expression was significantly higher in A. lucorum reared on Bt and conventional cotton than in A. lucorum reared on garland chrysanthemum and broad bean (P < 0.05), but there was no significant difference between AlVg or AlVg expression in A. lucorum reared on Bt and conventional cotton (P > 0.05). In addition, there were significant linear regression correlations between AlVg or AlVg expression and total mortality rate of nymphs, female lifespan, per female fecundity and egg hatching rates (P < 0.05). CONCLUSION Our results confirm that AlVg or AlVg is the key parameter affecting female fertility of A. lucorum. AlVg and AlVg expression can be influenced by different host nutrients except for Bt toxin. © 2015 Society of Chemical Industry
      PubDate: 2016-01-22T07:37:18.362536-05:
      DOI: 10.1002/ps.4203
  • The effect of synthetic pesticides and sulfur used in conventional and
           organically grown strawberry and soybean on Neozygites floridana, a
           natural enemy of spider mites
    • Pages: 1752 - 1757
      Abstract: Background The beneficial fungus Neozygites floridana kills the two‐spotted spider mite Tetranychus urticae, which is a serious polyphagous plant pest worldwide. Outbreaks of spider mites in strawberry and soybean have been associated with pesticide applications. Pesticides may affect N. floridana and consequently the natural control of T. urticae. N. floridana is a fungus difficult to grow in artificial media, and for this reason, very few studies have been conducted with this fungus, especially regarding the impact of pesticides. The aim of this study was to conduct a laboratory experiment to evaluate the effect of pesticides used in strawberry and soybean crops on N. floridana. Results Among the pesticides used in strawberry, the fungicides sulfur and cyprodinil + fludioxonil completely inhibited both the sporulation and conidial germination of N. floridana. The fungicide fluazinam affected N. floridana drastically. The application of the fungicide tebuconazole and the insecticides fenpropathrin and abamectin resulted in a less pronounced negative effect on N. floridana. Except for epoxiconazole and cyproconazole, all tested fungicides used in soybean resulted in a complete inhibition of N. floridana. Among the three insecticides used in soybean, lambda‐cyhalothrin and deltamethrin resulted in a significant inhibition of N. floridana. Conclusion The insecticides/ acaricides abamectin and lambda‐cyhalothrin at half concentrations and fenpropathrin and permethrin and the fungicide tebuconazole at the recommended concentrations resulted in the lowest impact on N. floridana. The fungicides with the active ingredients sulfur, cyprodinil + fludioxonil, azoxystrobin, azoxystrobin + cyproconazole, trifloxystrobin + tebuconazole and pyraclostrobin + epoxiconazole negatively affected N. floridana. © 2015 Society of Chemical Industry
      PubDate: 2016-02-01T03:59:15.680759-05:
      DOI: 10.1002/ps.4204
  • Confirmation and mechanism of glyphosate resistance in tall windmill grass
           (Chloris elata) from Brazil
    • Authors: Caio ACG Brunharo; Eric L Patterson, Daniela R Carrijo, Marcel SC de Melo, Marcelo Nicolai, Todd A Gaines, Scott J Nissen, Pedro J Christoffoleti
      Pages: 1758 - 1764
      Abstract: BACKGROUND Overreliance on glyphosate as a single tool for weed management in agricultural systems in Brazil has selected glyphosate‐resistant populations of tall windmill grass (Chloris elata Desv.). RESULTS Two C. elata populations, one glyphosate resistant (GR) and one glyphosate susceptible (GS), were studied in detail for a dose–response experiment and for resistance mechanism. The dose causing 50% reduction in dry weight was 620 g a.e. ha−1 for GR and 114 g ha−1 for GS, resulting in an R/S ratio of 5.4. GS had significantly higher maximum 14C‐glyphosate absorption into the treated leaf (51.3%) than GR (39.5%), a difference of 11.8% in maximum absorption. GR also retained more 14C‐glyphosate in the treated leaf (74%) than GS (51%), and GR translocated less glyphosate (27%) to other plant parts (stems, roots and root exudation) than GS (36%). There were no mutations at the Pro106 codon in the gene encoding 5‐enolpyruvylshikimate‐3‐phosphate synthase (EPSPS). There was no difference in EPSPS genomic copy number or EPSPS transcription between GS and GR populations. CONCLUSION Based on these data, reduced glyphosate absorption and increased glyphosate retention in the treated leaf contribute to glyphosate resistance in this C. elata population from Brazil. © 2015 Society of Chemical Industry
      PubDate: 2016-02-04T04:41:58.064184-05:
      DOI: 10.1002/ps.4205
  • Visual and olfactory enhancement of stable fly trapping
    • Pages: 1765 - 1771
      Abstract: BACKGROUND Stable flies are considered to be one of the major blood‐feeding pests in the US livestock industry, causing losses running into billions of dollars annually. Adult stable flies are highly attracted to Alsynite traps; however, Alsynite is becoming increasingly difficult to obtain and is expensive. RESULTS Here, we report on the development of a less expensive and more efficacious trap based upon a white panel with the option to add visual and olfactory stimuli for enhanced stable fly trapping. White panel traps caught twice as many stable flies than Alsynite traps. Baiting the traps with synthetic manure volatiles increased catches 2–3‐fold. Electroretinographic recordings of stable flies showed strong peaks of visual sensitivities occurring at 330–360 nm, 460–525 nm and 605–635 nm. A laboratory study indicated that young stable flies are more responsive to white, whereas gravid females prefer blue; in the field, white traps caught more stable flies than patterned or blue‐black traps. CONCLUSION Stable fly control can be enhanced by developing more efficient trapping systems with added visual and olfactory stimuli. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.
      PubDate: 2016-01-25T07:31:29.37548-05:0
      DOI: 10.1002/ps.4207
  • Toxicity to Diaphania hyalinata, selectivity to non‐target species
           and phytotoxicity of furanones and phthalide analogues
    • Pages: 1772 - 1777
      Abstract: BACKGROUND Despite being of great importance to crop protection, the disadvantages of intensive and inappropriate use of pesticides have stimulated the search for more selective and less harmful agrochemicals. Thus, we have evaluated the effectiveness of 16 synthetic molecules (phthalides and precursors) to control the melonworm Diaphania hyalinata, a key pest in cucurbit crops of economic importance in Brazil. The selectivity to beneficial organisms Solenopsis saevissima and Tetragonisca angustula and the phytotoxicity to Cucumis sativus of the promising insecticides were also assessed. RESULTS In the screening assay, compounds 1 and 6 provided 91 and 88% mortality of the melonworm. Compound 1 presented higher toxicity (median lethal dose LD50 = 15.99 µmol g−1) and higher speed on pest control (median survival time LT50 = 420 min) than compound 6 (LD50 = 44.51 µmol g−1 and LT50 = 840 min). Both compounds inhibited less than 11% of host‐plant growth and caused ≤36 and ≥93% mortality of predator and pollinator respectively. CONCLUSION Among the tested compounds, only compounds 1 and 6 were effective in melonworm control. Both compounds presented no considerable phytotoxicity and were selective to predator but non‐selective to pollinator, which enables their application for pest control if the exposure of the bees is minimised. © 2015 Society of Chemical Industry
      PubDate: 2016-01-18T04:06:24.008815-05:
      DOI: 10.1002/ps.4210
  • Insecticide resistance and diminished secondary kill performance of bait
           formulations against German cockroaches (Dictyoptera: Blattellidae)
    • Authors: Alexander E Ko; Donald N Bieman, Coby Schal, Jules Silverman
      Pages: 1778 - 1784
      Abstract: BACKGROUND Bait formulations are considered to be the most effective method for reducing German cockroach (Blattella germanica) infestations. An important property of some bait formulations is secondary kill, whereby active ingredient (AI) is translocated in insect‐produced residues throughout the cockroach population, especially affecting relatively sedentary early‐instar nymphs. RESULTS B. germanica was collected from a location where baits containing hydramethylnon, fipronil or indoxacarb had become ineffective, and these AIs were topically applied to adult males. Results revealed the first evidence for hydramethylnon resistance, moderate resistance to fipronil and extremely high resistance to indoxacarb. Insecticide residues excreted by field‐collected males that had ingested commercial baits effectively killed nymphs of an insecticide‐susceptible laboratory strain of B. germanica but failed to kill most nymphs of the field‐collected strain. CONCLUSIONS We report three novel findings: (1) the first evidence for hydramethylnon resistance in any insect; (2) extremely high levels of indoxacarb resistance in a field population; (3) reduced secondary mortality in an insecticide‐resistant field‐collected strain of B. germanica. We suggest that, while secondary mortality is considered to be advantageous in cockroach interventions, the ingestion of sublethal doses of AI by nymphs may select for high insecticide resistance by increasing the frequency of AI resistance alleles within the population. © 2015 Society of Chemical Industry
      PubDate: 2016-01-27T04:21:30.090419-05:
      DOI: 10.1002/ps.4211
  • Thiamethoxam and imidacloprid drench applications on sweet orange nursery
           trees disrupt the feeding and settling behaviour of Diaphorina citri
           (Hemiptera: Liviidae)
    • Pages: 1785 - 1793
      Abstract: BACKGROUND Chemical control is the method most used for management of Diaphorina citri, the vector of the phloem‐limited bacteria associated with citrus huanglongbing (HLB) disease. The objectives of this study were to determine the influence of soil‐drench applications of neonicotinoids (thiamethoxam and imidacloprid) on the probing behaviour of D. citri on citrus nursery trees, using the electrical penetration graph (EPG) technique, and to measure the D. citri settling behaviour after probing on citrus nursery trees that had received these neonicotinoid treatments. RESULTS The drench applications of neonicotinoids on citrus nursery trees disrupt D. citri probing, mainly for EPG variables related to phloem sap ingestion, with a significant reduction (≈90%) in the duration of this activity compared with untreated plants in all assessment periods (15, 35 and 90 days after application). Moreover, both insecticides have a repellent effect on D. citri, resulting in significant dispersal of psyllids from treated plants. CONCLUSIONS This study clearly demonstrates the interference of soil‐applied neonicotinoids on the feeding and settling behaviour of D. citri on citrus nursery trees, mainly during the phloem ingestion phase. These findings reinforce the recommendation of drench application of neonicotinoids before planting nursery trees as a useful strategy for HLB management. © 2015 Society of Chemical Industry
      PubDate: 2016-02-01T05:47:03.964893-05:
      DOI: 10.1002/ps.4213
  • Selection and characterization of resistance to the Vip3Aa20 protein from
           Bacillus thuringiensis in Spodoptera frugiperda
    • Authors: Oderlei Bernardi; Daniel Bernardi, Renato J Horikoshi, Daniela M Okuma, Leonardo L Miraldo, Julio Fatoretto, Fernanda CL Medeiros, Tony Burd, Celso Omoto
      Pages: 1794 - 1802
      Abstract: BACKGROUND Spodoptera frugiperda is one the main target pests of maize events expressing Vip3Aa20 protein from Bacillus thuringiensis (Bt) in Brazil. In this study, we selected a resistant strain of S. frugiperda on Bt maize expressing Vip3Aa20 protein and characterized the inheritance and fitness costs of the resistance. RESULTS The resistance ratio of the Vip3Aa20‐resistant strain of S. frugiperda was >3200‐fold. Neonates of the Vip3Aa20‐resistant strain were able to survive and emerge as fertile adults on Vip3Aa20 maize, while larvae from susceptible and heterozygous strains did not survive. The inheritance of Vip3Aa20 resistance was autosomal recessive and monogenic. Life history studies to investigate fitness cost revealed an 11% reduction in the survival rate until adult stage and a ∼50% lower reproductive rate of the Vip3Aa20‐resistant strain compared with susceptible and heterozygous strains. CONCLUSION This is the first characterization of S. frugiperda resistance to Vip3Aa protein. Our results provide useful information for resistance management programs designed to prevent or delay resistance evolution to Vip3Aa proteins in S. frugiperda. © 2016 Society of Chemical Industry
      PubDate: 2016-02-09T07:57:10.971875-05:
      DOI: 10.1002/ps.4223
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