吡虫啉对家蚕的毒性试验

Toxicity Evaluation of Imidacloprid to Silkworm Bombyx mori

10%吡虫啉可湿性粉剂对家蚕3龄起蚕的急性食下毒性(LC50)为1.2841mg/L,对家的毒性等级为高毒;晚秋蚕期用10%吡虫啉可湿性粉剂稀释液喷雾的桑叶喂饲3龄起蚕,1500倍(66.67mg/L)处理区约在35d时不再出现中毒死亡,750倍(133.33mg/L)到39d时仍有38.89%的蚕死亡,表明吡虫啉在桑叶上的残留毒性较长,但未见桑叶内吸传导毒性。吡虫啉对家蚕的中毒症状主要表现为胸部膨大、摇头、吐液、爬动,头尾向背弯曲呈“U”或“O”字形。

The acute ingested toxicity (LC50) of 10% imidacloprid wettable powder to the third instar silkworm is 1.2841mg/L, which is highly toxic to the silkworm. In late autumn silkworm rearing season, there was no toxic symptom observed when 3rd instar silkworms were fed with mulberry leaves sprayed with 1500 times (66.67 mg/L) of 10% imidacloprid wettable powder diluent after 35 d, however, 38.89% dead silkworms were observed in the treatment of 750 times (133.33 mg/L) at 39 d, indicating that the residual toxicity of imidacloprid on mulberry leaves was very long, but no conduction toxicity through absorption of imidacloprid by mulberry leaves was observed. The poisoning symptoms of silkworm were mainly manifested by chest enlargement, shaking head, spitting and crawling,and the head and tail bending back in the shape of "U" or "O".