两种敌敌畏乳油对家蚕的毒性和残毒期比较

Comparison of Toxicity and Residual Period of Two Types of Dichlorvos EC to Silkworm Bombyx mori

90%敌敌畏乳油是一种新开发的高含量制剂,本文以77.5%敌敌畏乳油为对照,比较两种敌敌畏乳油对养蚕生产的安全性。试验结果显示:90%敌敌畏乳油对家蚕3龄起蚕的急性食下毒性(LC50)为17.6212 mg/L,与77.5%敌敌畏乳油的16.1004 mg/L均达到高毒级;用90%敌敌畏乳油500倍、1000倍和1500倍稀释液喷洒的桑叶饲喂3龄起蚕,残毒期分别为3 d、1 d和1 d,略短于77.5%敌敌畏乳油1000倍的3 d;两种敌敌畏乳油稀释液处理的桑叶在低温避光条件下,毒性降解时间比田间残毒期大幅度延长。结论:90%敌敌畏乳油对家蚕的急性食下毒性及其在桑叶上的残毒期略低于77.5%敌敌畏乳油,但用于防治桑园害虫时建议选择登记在桑树上的农药产品。

90%dichlorvos EC is a newly developed high concentration preparation,to find its safety dosage to silkworm Bombyx mori,77.5%dichlorvos EC was used as the control and comparative experiment was carried out in this study.The results showed that:the acute toxicity(LC50)of 90%dichlorvos EC to the 3rd instar silkworm was 17.6212 mg/L,which was higher than that of 77.5%dichlorvos EC(16.1004 mg/L);the residual toxicity of 90%dichlorvos EC was 3 d,1 d and 1 d when 500,1000 and 1500 dilutions of 90%dichlorvos EC was sprayed to the newly exuviated larvae of third instar,which was slightly shorter than that of 77.5%dichlorvos EC(1000 times).The degradation of dichlorvos emulsifiable concentrate was significantly longer when the mulberry leaves treated with the two type of dichlorvos EC were preserved in low temperature and dark conditions if compared with that of mulberry trees in field.Conclusion:the acute toxicity of 90%dichlorvos EC to silkworm and its residual toxicity period on mulberry leaves are slightly lower than 77.5%dichlorvos EC,hit is suggested to choose the pesticide registered on mulberry trees when it is used to control mulberry pests.