杀虫剂对菜蛾啮小蜂的毒性

TOXICITY OF INSECTICIDES TO OOMYZUS SOKOLOWSKII, A PARASITOID OF DIAMONDBACK MOTH

本试验评价了１１种杀虫剂（分属有机磷、拟除虫菊酯、氨基甲酸酯、昆虫生长调节剂、杀虫抗生素、沙蚕毒素及微生物农药）对菜蛾啮小蜂的影响。供试浓度为田间防治推荐浓度，用试管药膜法测定农药对成虫的毒性，用浸渍法测定农药对蛹的影响。结果表明，农药对成虫的击倒能力的顺序依次为：辛硫磷≌万灵＞巴丹＞乐果＞敌杀死≌功夫＞害极灭≌虫螨光＞杀灭菊酯＞抑太保≌Ｂｔ；其触杀活性的顺序为：辛硫磷≌乐果≌万灵＞敌杀死≌功夫≌巴丹＞害极灭≌虫螨光＞杀灭菊酯＞抑太保≌Ｂｔ。供试的５种杀虫剂（即乐果、杀灭菊酯、虫螨光、抑太保和Ｂｔ）不影响菜蛾啮小蜂蛹的发育和羽化，但乐果对羽化后的成虫有极高的毒性。

Toxicity of eleven commonly used insecticides (including organophosphates, synthetic pyrethroids, carbamates, insect growth regulators, antibiotics, nereistoxin and microbial insecticides) to Oomyzus sokolowskii was evaluated in the laboratory. All insecticides were applied at concentrations recommended for field application by the producers. Adults were exposed to fresh, dry insecticide film in glass vials for 05, 2 and 24 h, respectively, and were then transferred to clean vials and kept for a further 24 h for observation. Pupae were dipped into insecticides for 10 s, and emergence of adults and the mortality 24 h after emergence were recorded. Results showed that the rates of knockdown by the insecticides to adults were in the following decreasing order: phoxim≌methomyl>cartap>dimethoate>deltamethrin≌cyhalothrin>abamectin≌avermectin>fenvalerate>chlorfluazuron≌Bt, and the order of contact toxicity to the adults were: phoxim≌dimethoate≌methomyl>deltamethrin≌cyhalothrin>cartap>abamectin≌avermectin>fenvalerate>chlorfluazuron≌Bt. Five insecticides (dimethoate, fenvalerate,avermectin, chlorfluazuron and Bt) were shown to be harmless to the pupae, however, dimethoate was toxic to the adults emerging from the treated pupae. 