Effects of six selected orchard insecticides on Neoseiulus fallacis (Acari: Phytoseiidae) in the laboratory

BACKGROUND: Neoseiulus fallacis (Garman) is a key predator of tetranychid mites in integrated pest management (IPM) programs across Canada. This study identified compounds that would be recommended for tier‐II field evaluations in an IPM program. RESULTS: The overall egg mortality caused by the six insecticides was negligible as it extended from 0 to 12.1%. Imidacloprid was classified as toxic to adults. The label rate was 7.73‐fold the LC₅₀. Thiamethoxam was classified as moderately toxic to adults, and its label rate was 2.87‐fold the LC₅₀. Acetamiprid and spinosad were classified as marginally toxic, and their label rates were respectively 0.99‐ and 0.45‐fold the LC₅₀ for adults. Thiacloprid and methoxyfenozide were virtually innocuous to adults. CONCLUSION: Methoxyfenozide was totally harmless to all stages of N. fallacis, and it would be included in IPM programs immediately. Acetamiprid, spinosad and thiacloprid had varying degrees of mild toxicity to at least one growth stage of the predator. Therefore, they were recommended for tier‐II field testing according to their label claims. Imidacloprid and thiamethoxam were toxic to moderately toxic to adults and had significant adverse effects on fecundity. Therefore, they would be field evaluated only if alternatives were unavailable. Copyright 2010 Crown in the right of Canada. Published by JohnWiley & Sons, Ltd     

不同药剂防治秋豇豆白粉虱效果探讨

为减轻豇豆白粉虱的发生,减少化学农药用量、残留和环境污染,采用测报调查、随机区组设计和统计分析等方法,开展了化学农药呋虫胺、啶虫脒和吡蚜酮,生物农药阿维菌素防治豇豆温室白粉虱农药田间药效试验。结果表明:在温室大棚秋季豇豆白粉虱发生较重情况下,每公顷用1.8%阿维菌素EC 375 g、20%呋虫胺SP(护瑞)600 g、5%啶虫脒WP 600 g、25%吡蚜酮WP 600 g(对照药剂),5~8天施药1次,连续施用3次,药后7、14、20天,防治效果分别达90.9%、97.0%、88.0%、93.9%,97.4%、92.1%、84.2%、89.4%和95.6%、86.7%、82.2%、84.5%,且药后7天呋虫胺与阿维菌素和吡蚜酮,极显著高于啶虫脒,阿维菌素与啶虫脒和吡蚜酮之间差异不显著;药后14天,阿维菌素与呋虫胺和吡蚜酮差异不显著,极显著高于啶虫脒,呋虫胺与吡蚜酮差异不显著,显著高于啶虫脒;药后20天,阿维菌素极显著高于呋虫胺、啶虫脒和吡蚜酮,呋虫胺与啶虫脒和吡蚜酮差异不显著。同时,生物农药阿维菌素在药后7天,防效稍低于化学农药呋虫胺,药后14天,防效高于呋虫胺,药后20天,防效极显著高于呋虫胺。这4种药剂尤其是生物农药阿维菌素不仅可以作为防治温室白粉虱的理想药剂,而且可以作为现代农业示范区、无公害农产品、绿色农产品和有机农产品的理想药剂。     

Rapid report acetamiprid resistance and cross-resistance in the diamondback moth, Plutella xylostella

A 110-fold acetamiprid-resistant Plutella xylostella (L) strain was established after four selection experiments (in five generations) on a 9.5-fold resistant colony in the laboratory. The resistant strain did not show cross-resistance to chlorfluazuron or Bacillus thuringiensis subsp kurstaki Berliner, but displayed low resistance to cartap and phenthoate.     

季铵盐和有机硅助剂对啶虫脒杀虫活性及水生生物毒性的影响

分别以浸渍法和相加指数法,评价了5种季铵盐助剂和3种有机硅助剂分别与啶虫脒混合使用时对苹果黄蚜Aphis citricola的联合作用,以及对两种非靶标水生环境生物大型溞Daphnia magna和斑马鱼Brachydonio rerio的毒性。结果表明,有机硅助剂和季铵盐助剂对啶虫脒防治蚜虫具有明显的增效作用,且silwet 618的增效倍数高达210.2。环境毒性试验结果表明:啶虫脒对两种水生生物均为低毒;供试季铵盐和有机硅助剂对大型溞的单一毒性均为剧毒,季铵盐助剂对斑马鱼为高毒,而有机硅助剂对斑马鱼为中毒。与农药联合作用测定结果表明:有机硅助剂对两种水生生物均表现为增毒作用;而5种季铵盐助剂除十四烷基二甲基苄基氯化铵（1427）对大型溞表现为增毒作用外,其他4种对两种水生生物均呈现不同程度的拮抗作用。此外,季铵盐和有机硅助剂还可以显著降低清水的表面张力（由清水的74.37 mN/m降为20.50~40.07 mN/m）,提高叶片上的最大持留量（由清水的1.54 μg/cm2提高到2.39~4.34 μg/cm2）。因此,使用季铵盐和有机硅助剂作为增效剂时应考虑其对水生生物的毒性,其中季铵盐助剂对环境生物的潜在威胁更小。     

金银花干制和冲泡过程中吡虫啉和啶虫脒的残留行为

为了研究金银花在干制和冲泡过程中吡虫啉和啶虫脒的残留行为,利用高效液相色谱法对其进行分析,结果显示,吡虫啉和啶虫脒在金银花和茶汤2种基质中的添加回收率为80.8%~94.5%,变异系数为0.5%~6.7%。晒干、阴干和烘干3种干制方法对金银花中的两种农药均有一定的消解作用,吡虫啉和啶虫脒残留的消解百分数分别为30.9%~78.3%和25.1%~78.0%,其中,晒干和高温烘干处理具有更高的消解百分数。在不同农药浓度、冲泡次数、茶水比和浸泡时间以及加不加盖子等冲泡条件下,金银花中的吡虫啉和啶虫脒残留分别有7.7%~26.3%和6.5%~39.4%转移至茶汤。可见合理的干制方法和冲泡条件可以减少吡虫啉和啶虫脒残留向人体的转移。     

毛叶枣中多菌灵、吡虫啉和啶虫脒消解动态研究

采用超高效液相色谱—串联质谱,研究了多菌灵、吡虫啉和啶虫脒在毛叶枣中的消解动态和最终残留量。毛叶枣样品经乙腈提取,低温冷冻液萃取后,采用正离子多反应监测模式（MRM）测定,结果表明：在 0.1~10 μg/L范围内,3 种农药的线性关系良好,检出限为 0.06 μg/kg,定量限为 0.20 μg/kg,回收率范围为 89.1%~97.0%,相对标准偏差为 5.3%~6.9%。田间试验结果表明,多菌灵、吡虫啉和啶虫脒在毛叶枣中的消解半衰期分别为 3.2、3.3、2.8 d,最终残留试验结果表明,在毛叶枣采收期时 3 种农药均有低含量检出,表明 3 种农药在毛叶枣上的残留时期较长,喷施时需控制好喷施浓度和间隔期。     

葡萄中几种常用防治绿盲蝽农药的残留动态与风险评估

为探明葡萄中常用的几种防治绿盲蝽农药的残留规律和膳食风险,开展3种常用农药甲氨基阿维菌素苯甲酸盐(甲维盐)、噻虫嗪和啶虫脒在葡萄中的残留动态及膳食风险研究。结果表明,甲维盐、噻虫嗪、啶虫脒在葡萄中的降解均符合一级动力学方程,且使用14 d后均可降解至农药最高残留限量(MRL)值以下。3种农药在降解14 d的残留量的膳食风险评估结果表明,3种农药的慢性风险、急性风险和全膳食风险均小于100%,说明按照推荐的使用方法所选3种试验农药使用14 d后膳食风险较低,可以推荐用于绿盲蝽的防治,推荐安全间隔期为14 d。