Bt制剂对小菜蛾及其主要寄生蜂的选择毒性

测定了6种Bt制剂对小菜蛾幼虫的毒力及其寄生蜂菜蛾绒茧蜂和菜蛾啮小蜂成虫的选择毒性。6种Bt制剂对小菜蛾3龄幼虫的毒力差异显著，毒力大小顺序为：绿茵〉高效Bt／杀虫单〉Bt可湿性粉剂〉苏泰〉农泰〉比力Bt（8010）浓缩型粉剂。Bt制剂对小菜蛾主要寄生蜂的选择毒性研究结果如下，绿茵和苏泰对菜蛾绒茧蜂成虫属于有害类药剂，比力、高效Bt／杀虫单和农泰属于中度有害类杀虫剂，Bt可湿性粉剂属于无害类药剂；绿茵、高效Bt／杀虫单对菜蛾啮小蜂成虫属于有害类药剂，具有很强的杀伤力，比力和苏泰属于中度有害类杀虫剂，Bt可湿性粉剂和农泰属于无害类药剂。

Selective Toxicities of Several Bt Preparations to Diamondback Moth and Its Parasitoids

Selective toxicities of Bt preparations to diamondback moth(DBM) larvae were evaluated by leaf-dip bioassays,and those of its main parasites such as Cotesia plutellae Kurdjumov and Oomyzus sokolowskii Kurdjumov to field concentrationse of 6 Bt preparations were evaluated by vial residual method.The order of the toxicities of 6 Bt preparations to the larvae of DBM was luying> high effectual Bt/Shachongdan > Bt soluble powder>Sutai>Nongtai>BiliBt(8010) suspension concentration.Luying is the highest toxic to O.sokolowskii Kurdjumov,According to the indexes proposed by Guoyujie(1995),luying fell into deleterious preparation.Bili(8010) into low toxicity preparation and Nongtai and Bt into innocuous preparations;the 6 Bt preparations Sutai was the highest toxic to C.plutellae Kurdjumov and its adult mortality reached 66.67%.After contacting film for one day,bili(8010) was the second highest toxic to C.Kurdjumov.Bt soluble powder,nongtai,Bt/Shachongdan were harmless to C.Kurdjumov.