三类生物源农药及其混配制剂对家蚕的毒性与评价

Toxicity Evaluation of Three Kinds of Biogenic Pesticides and Their Mixed Preparations to Silkworm

为明确阿维菌素类、氯化烟酰类和拟除虫菊酯类农药对家蚕的毒性,采用食下毒叶法测定了阿维菌素、甲氨基阿维菌素苯甲酸盐、吡虫啉、高效氯氰菊酯及其混配制剂共15种生物源农药对家蚕2龄幼虫的毒性,并观察了家蚕中毒症状。结果表明:将15种农药分别配制成不同梯度浓度的药液浸渍桑叶饲喂家蚕48 h后,各种药剂对家蚕的LC50值均小于0.5 mg/kg,属剧毒级农药,对家蚕有极高风险性;各种药液处理引起的家蚕中毒症状表现出多种相似的特征,如有吐液、翘头、翘尾、身体扭曲呈"C"或"S"形等。试验证明阿维菌素、甲氨基阿维菌素苯甲酸盐、吡虫啉、高效氯氰菊酯及其混配制剂不适合在桑园及其附近农田使用,同时也验证了对高等动物毒性低的农药并非就对非靶标生物具有安全性。

In order to identify the toxicities of avermectins, chloronicotinyl and pyrethroid pesticides to silkworm （ Bombyx mori）, we determined the toxicities of the 15 biogenic pesticides （including abamectin, emamectin benzoate, imidacloprid and β-cypermethrin and their mixed formulations） to 2nd instar larvae with the leaf dipping method. At the same time, the poisoning symptoms of treated silkworm were observed. The results showed that the LCso values of 15 biogenic pesticides to 2nd instar larvae were less than 0.5 mg/kg after 48 h of exposure respectively, the poisoning symptoms of treated silkworm were similar, which was vomiting, head or tail bending upwards, and body distorting to ＂C＂ or ＂S＂ shaped etc. It suggested that these pesticides should not be used in mulberry field because of their high toxicities. Our results indicated that pesticide with low toxicity to vertebrate is not necessarily safe to non-target insects simultaneously.