桑园治虫新药40%“乐桑”乳油对家蚕的残毒期测定

Determining of Intervals of 40% Lesang Emulsion(Chlorpyrifos) Residual Toxicant Effects on Silkworms

以266 mg/L 40%“乐桑”乳油在桑园里喷雾治虫,春季分别在喷药后第19、20、21天,秋季分别在喷药后第17、18和19天采叶喂蚕,统计2个季节各处理与相应对照的虫蛹生命率、茧层量和全茧量。利用M ann-W h itney U精确p值的Monte Carlo估计值进行统计检验,结果表明:该药对家蚕的残毒期春季为20 d,秋季为18 d。

Intervals of chlorpyrifos＇s residual toxicant effects on the silkworm were evaluated through testing statistical significance of larva-pupa survival rate, cocoon shell weight and whole cocoon weight of varied time spans among treatments and their corresponding controls. Silkworms were subsisted on mulberry leaves treated by 266 mg/L chlorpyrifos and water （control） in the fields from third instar to cocooning in spring or autumn. The corresponding Mann-Whitney U＇s estimates of the exact p values （one-tailed） were computed by the results of the Monte Carlo analysis. The results revealed that the safe intervals of chlorpyrifos residual toxicant effects to silkworms were 20 days and 18days in springtime and autumn, respectively.