Effect of seven new orchard pesticides on Galendromus occidentalis in laboratory studies

BACKGROUND: Biological control of phytophagous mites in orchards requires that pesticides used to manage other arthropod pests or diseases are harmless to predacious mites, as these are essential to keep phytophagous mites at non‐injurious population levels. This study evaluates the possible toxic attributes of acetamiprid, imidacloprid, thiacloprid, thiamethoxam, spirodiclofen, spinosad and methoxyfenoxide currently used in western Canadian orchards. RESULTS: None of these pesticides has any ovicidal properties against Galendromus occidentalis (Nesbitt). Imidacloprid and acetamiprid were highly toxic to the adults and reduced fecundity significantly. Thiamethoxam and spirodiclofen were non‐toxic to adults, but they slightly reduced fecundity. Thiacloprid, spinosad and methoxyfenoxide were harmless to adults and had no effect on fecundity. All compounds showed some repellence at 24 h intervals for 72 h. CONCLUSIONS: Imidacloprid and acetamiprid are incompatible with IPM programs because they are toxic to adults and negatively affect fecundity. Thiamethoxam and spirodiclofen need further field evaluation to determine if they are compatible with IPM programs because they slightly reduced fecundity. Thiacloprid, spinosad and methoxyfenoxide are harmless to adults, but they are slightly repellent. Therefore, with the exception of imidacloprid and acetamiprid, all these compounds should be field tested for compatibility in an IPM program. © Her Majesty the Queen in Right of Canada, as represented by the Minister of Agriculture and Agri‐Food Canada. Published by John Wiley & Sons, Ltd     

亚致死浓度多杀菌素对西花蓟马解毒酶系活力的影响

采用亚致死浓度(LC25)多杀菌素对西花蓟马Frankliniella occidentalis相对敏感(SS)种群进行连续选育,获得亚致死(Sub)种群。处理36代后,Sub种群对多杀菌素的敏感性下降到SS种群的5.2倍。用SS和Sub种群各自的LC10和LC25浓度多杀菌素分别处理两种群的2龄若虫,1、6 、12、24和48 h后测定羧酸酯酶(CarE)、谷胱甘肽S-转移酶(GSTs) 和多功能氧化酶(MFOs)的比活力。结果表明,Sub种群对照组CarE和GSTs比活力在除第48 h外的其他时间段都高于SS种群对照组,且6 h时两者CarE比活力差异显著,Sub种群是SS种群的1.37倍;Sub种群对照组MFOs比活力在各时间段都高于SS种群对照组,在1 和6 h时差异显著,前者分别是后者的1.62和1.36倍。再经各自的LC10和LC25浓度多杀菌素处理后,在各时间段Sub种群的CarE比活力均高于SS种群;LC25浓度处理后,Sub种群的GSTs和MFOs比活力虽在短时间内低于SS种群,但随处理时间的延长其比活力均高于SS种群。说明SS种群经亚致死浓度多杀菌素选育36代后,其体内CarE、GSTs和MFOs比活力有上升趋势;继续用亚致死浓度多杀菌素处理,则Sub种群体内解毒酶活力的动态调节能力要强于SS种群。     

多杀菌素对不同发育阶段甜菜夜蛾的毒力及其体内超氧化物歧化酶、过氧化氢酶和过氧化物酶的影响

对甜菜夜蛾的毒力测定结果表明,多杀菌素能显著降低其初孵幼虫的存活率、成虫的产卵量和成虫寿命。经6.25 μg/mL药液处理的卵,其初孵幼虫存活率仅为7.48％,而对照则为76.72％;取食12.50 μg/L药液的成虫,其产卵量和成虫寿命仅为取食蜂蜜水的1/6和1/2.5。随虫龄的增加,甜菜夜蛾幼虫对多杀菌素的敏感性显著降低,3龄、4龄幼虫的敏感性仅为2龄幼虫的1/9和1/16,且增效剂氧化胡椒基丁醚(PBO)与磷酸三苯酯(TPP)表皮点滴处理不表现增效作用。多杀菌素对甜菜夜蛾卵的孵化率、蛹重以及蛹的羽化率没有明显影响。亚致死剂量处理3龄幼虫后,其体内超氧化物歧化酶、过氧化氢酶和过氧化物酶等主要保护酶系的活性在处理后0~24 h与对照差异不明显,保护酶系与甜菜夜蛾对多杀菌素敏感性之间没有明显关系。     

小菜蛾抗多杀菌素和敏感品系耐低温能力的比较

通过杂交筛选得到小菜蛾对多杀菌素敏感和高抗的纯合子品系，对二个品系在适温和经低温处理后的生长发育特性进行了比较，以探明其抗性是否伴有适合度的变化以及适合度变化与温度的关系。结果发现:高抗品系的卵经6℃低温处理14 d，孵化出的幼虫仅有7.7％正常化蛹，显著低于敏感品系61.4％的正常化蛹率；经6℃低温处理28 d，高抗和敏感品系的卵孵化率分别为27％和75％，二者差异显著；高抗品系的蛹经 5℃低温处理7～14 d后，蛹的 发育历期显著延长，其子代卵的存活力也显著下降。在适温25℃下，抗性和敏感品系之间多项生物学特性均无显著差异或差异很小。这些结果表明，小菜蛾对多杀菌素的抗性伴随有耐低温能力的适合度代价。     

多杀霉素亚致死浓度对棉铃虫幼虫生理及代谢的影响

为明确田间使用多杀霉素亚致死浓度对棉铃虫Helicoverpa armigera幼虫的影响,用含多杀霉素亚致死浓度LC₂₅的人工饲料持续饲喂棉铃虫3龄幼虫,并对饲喂后其体重、取食量、累计蛹化率、蛹发育历期和蛹重等生长发育及脂肪体内甘油三脂（triglyceride,TG）含量和相关基因SREBP、FAS和HSL表达情况进行测定。结果表明,多杀霉素对棉铃虫的亚致死浓度LC₂₅为0.21 mg/kg;多杀霉素亚致死浓度处理4~6 d后,棉铃虫3龄幼虫体重分别为0.065、0.263和0.329 g,较对照显著降低;处理6 d后,其取食量为0.082 g,较对照显著降低;处理4~7 d后,其累计化蛹率分别为60.90%、63.20%、65.50%和65.50%,较对照显著降低。多杀霉素亚致死浓度处理后,棉铃虫蛹发育历期由对照9.89 d显著延长至10.74 d,单头蛹重为0.274 g,显著低于对照的0.324 g;其脂肪体TG含量较对照显著降低。多杀霉素亚致死浓度处理24~72 h后,参与脂肪酸合成信号通路中重要基因SREBP和FAS的相对表达量较对照均显著下调,而参与脂肪代谢的重要基因HSL则较对照显著上调。     

多素·除虫脲15%悬浮剂的研制

介绍了一种以水为介质的环保型新制剂多素.除虫脲15%悬浮剂,通过对分散剂及润湿分散剂品种的筛选,考察了配制的悬浮剂各种控制项目指标以及低温、热贮性能,并确定了最佳配方:多杀霉素2.5%,除虫脲12.5%,NNO 2%,SOPAS-270 1.5%,HT-20002.5%,黄原胶0.1%,CMC 0.5%,乙二醇5%,防腐剂0.3%,有机硅消泡剂0.08%,自来水补足至100%。结果表明,该悬浮剂配方质量稳定,分解率低,悬浮率高,使用安全,有良好的开发应用前景。     

Compatibility of spinosad with predaceous mites (Acari) used to control Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae)

BACKGROUND: Spinosad is a biopesticide widely used for control of Frankliniella occidentalis (Pergande). It is reported to be non‐toxic to several predatory mite species used for the biological control of thrips. Predatory mites Typhlodromips montdorensis (Schicha), Neoseiulus cucumeris (Oudemans) and Hypoaspis miles (Berlese) have been used for control of F. occidentalis. This study investigated the impact of direct and residual toxicity of spinosad on F. occidentalis and predatory mites. The repellency of spinosad residues to these predatory mites was also investigated. RESULTS: Direct contact to spinosad effectively reduced the number of F. occidentalis adults and larvae, causing > 96% mortality. Spinosad residues aged 2–96 h were also toxic to F. occidentalis. Direct exposure to spinosad resulted in > 90% mortality of all three mite species. Thresholds for the residual toxicity (contact) of spinosad (LT₂₅) were estimated as 4.2, 3.2 and 5.8 days for T. montdorensis, N. cucumeris and H. miles respectively. When mites were simultaneously exposed to spinosad residues and fed spinosad‐intoxicated thrips larvae, toxicity increased. Residual thresholds were re‐estimated as 5.4, 3.9 and 6.1 days for T. montdorensis, N. cucumeris and H. miles respectively. Residues aged 2–48 h repelled T. montdorensis and H. miles, and residues aged 2–24 h repelled N. cucumeris. CONCLUSION: Predatory mites can be safely released 6 days after spinosad is applied for the management of F. occidentalis. Copyright © 2011 Society of Chemical Industry     

多杀菌素微球制备关键工艺研究:Ⅰ

采用乳化-溶剂挥发法,以聚乳酸(PLA)为成球材料制备了多杀菌素微球。研究了分散剂、自然光照、明胶质量浓度和反应温度对多杀菌素微球质量的影响规律。结果表明,以12.5 mg/mL的明胶水溶液作为反应体系的分散剂,在避光30~35 ℃下可制得粒径小且分布均匀、包封率高(＞98%)的多杀菌素微球。