为明确新烟碱类杀虫剂对非靶标生物家蚕的毒性以及对生态环境的安全性影响,采用浸叶法测定6种新烟碱类杀虫剂及其它3类对照杀虫剂对家蚕的急性毒性,并观察不同种类杀虫剂引起家蚕的急性中毒症状差异。6种新烟碱类杀虫剂中噻虫胺、吡虫啉、噻虫啉和烯啶虫胺对家蚕2龄幼虫96 h的LC50分别为0.065 1、0.174、0.258、0.445 mg/L,属剧毒级农药,噻虫嗪和啶虫脒对家蚕2龄幼虫96 h的LC50分别为1.31、2.73 mg/L,属高毒级农药,6种药剂均对家蚕存在极大的安全风险性。新烟碱类杀虫剂引起家蚕中毒的症状主要表现为拒食,身体扭曲呈"C"或"S"形,头部肿大等。其它3类杀虫剂中,抗生素类杀虫剂阿维菌素的毒性属剧毒级,并在测定药剂中的毒性最高,家蚕中毒症状主要表现为吐液、头部或尾部翘起、拒食等;有机磷类杀虫剂毒死蜱的毒性属高毒级,家蚕中毒症状与新烟碱类杀虫剂相似;吡咯类杀虫剂虫螨腈的毒性属中毒级。因新烟碱类杀虫剂对家蚕的毒性强,建议远离桑园使用,以避免对养蚕生产造成危害。
In order to identify the toxicity of neonicotinoid insecticides to non-target organism silkworm(Bombyx mori) and their impact on the security of ecological environment,we determined and compared the acute toxicity of 6 neonicotinoid insecticides and 3 other insecticides to silkworm with leaf dipping method.The differences in symptoms of acute toxicity caused by treatment with various kinds of insecticides were observed and recorded.The results indicated that,among the 6 neonicotinoid insecticides,LC50 of clothianidin,imidacloprid,thiacloprid and nitenpyram to the 2nd instar silkworm larvae at 96 h was 0.065 1,0.174,0.258 and 0.445 mg/L respectively,being pesticides of virulent toxicity grade.That of thiamethoxam and acetamiprid was 1.31 and 2.73 mg/L respectively,being pesticides of high toxicity grade.They all had great security risk on silkworm.The major poisoning symptoms on silkworm after treatment with neonicotinoid insecticides included antifeeding,body twisting into "C" or "S" shape,and head tumidity etc.In the other 3 insecticides,the antibiotic insecticide abamectin belonged to virulent toxicity grade and had the highest toxicity among all tested pesticides.Its main poisoning symptoms on silkworm were vomiting,head or tail bending upwards,and antifeeding etc.The organophosphate insecticide chlorpyrifos belonged to high toxicity grade and its poisoning sym-ptoms on silkworm were similar to neonicotinoid insecticides.The pyrroles insecticide chlorfenapyr belonged to middle toxicity grade.In consideration of their virulent toxicity on silkworm,it is suggested that neonicotinoid insecticides should be used far away from mulberry field to avoid damage on sericultural production.