农药在桑树上单一施用与混合施用对家蚕残毒期的测定

目的]调查混配农药残毒期。方法]采用敌敌畏、乐果以及双扑3种药剂的单一与混合1000倍稀释液喷施桑园,于施药后不同间隔时间采收桑叶饲喂家蚕,进行其对家蚕的残毒期测定。结果]单一喷施敌敌畏后第3天桑叶的饲蚕死亡率为36.7%,第5天为3.3%,第7天桑叶饲蚕无中毒和死亡现象。单一喷施乐果后第3天桑叶的饲蚕死亡率为6.7%,第5天桑叶饲蚕已无中毒现象。单一喷施双扑后第3天桑叶的饲蚕死亡率为100.0%;第5天为93.3%;第10天桑叶饲蚕仍有个别死亡或中毒现象。施药后第3天,各混剂处理桑叶饲蚕死亡率均超过80.0%;第5天,敌敌畏＋乐果处理桑叶饲蚕已无中毒现象,其他处理桑叶饲蚕死亡率依然很高;第7天,敌敌畏＋乐果处理桑叶饲蚕已无死亡和中毒表现。结论]单剂混合可能使残毒期缩短或延长。

Determination on Toxin Residual Period of Pesticides against Silkworm in Single and Mingled Applications on Mulberry Trees

Objective] The aim was to investigate the toxin residual periods of mingled pesticides.Method] The mulberry trees were sprayed with single and mingled 1 000-times dilutions of 3 pesticides of dichlorovos,dimethoate and Shuangpu,the mulberry leaves were harvested in different interval time after pesticide application for feeding silkworm and then their toxin residual periods against silkworm were determined.Result]The mortality of silkworm fed with mulberry leaves harvested on the 3rd day after single application of dichlorovos was 36.7% ,that of silkworm fed with mulberry leaves harvested on the 5th day was 3.3% and the silkworm fed with mulberry leaves harvested on the 7th day showed no poisoned or dead phenomenon.The mortality of silkworm fed with mulberry leaves harvested on the 3rd day after single application of dimethoate was 6.7% and the silkworm fed with mulberry leaves harvest on the 5th day showed no poisoned phenomenon.The mortality of silkworm fed with mulberry leaves harvested on the 3rd day after single application of Shuangpu was 100.0% ,that of silkworm fed with mulberry leaves harvested on the 5th day was 93.3% and the silkworm fed with mulberry leaves harvest on the 10th day still showed individual dead or poisoned phenomenon.The mortalities of silkworm fed with mulberry leaves harvested on the 3rd day after various mingled applications all exceeded 80.0% ; the silkworm fed with mulberry leaves sprayed with dichlorovos + dimethoate and harvested on the 5th day showed no poisoned phenomenon and the mortalities of silkworm fed with mulberry leaves in the other treatments were still high; the silkworm fed with mulberry leaves sprayed with dichlorovos + dimethoate and harvested on the 7th day showed no dead or poisoned phenomenon.Conclusion]The mingled applications of individual pesticides might shorten or extend toxin residual periods.