微量氯氰菊酯对家蚕的毒性

在桑园中喷施微量氯氰菊酯,用该桑叶连续喂饲2龄起蚕,调查一个龄期的死亡率。结果表明:喷施过1.08 μg/L氯氰菊酯的桑叶在经过63 d后,对家蚕依然存在致死作用;喷施过108.00 μg/L氯氰菊酯的桑园中,10 d后新生长桑叶未见对家蚕的致死作用。对家蚕3龄起蚕进行连续喂饲染毒桑叶的试验结果表明:0.11 ng/L氯氰菊酯将引起家蚕幼虫死亡率显著上升(P＜0.05)和眠蚕体重显著下降(P＜0.05);1.08 ng/L将引起幼虫死亡率的极显著上升(P＜0.01),以及眠蚕体重和全茧量的极显著下降(P＜0.01);10.80 ng/L将引起茧层率的极显著下降(P＜0.01)。

Toxicity of Low Dosage Cypermethrin to the Silkworm, Bombyx mori

Mulberry leaves sprayed with cypermethrin were continuously fed to 2rd instar silkworms till 3rd instar. The study on residual effect of the pesticide on mulberry indicated that leaves sprayed with 1.08 μg/L showed toxicity after 63 days, while 108.00 μg/L sprayed plants new sprouted leaves did not show toxicity even after 10 days. The effect of different concentrations of cypermethrin fed to 3rd instar larvae and its influence on larval mortality, larval weight during moult, cocoon weight, and shell ratio showed the mortality of silkworms and larval weight during moult fed with 0.11 ng/L cypermethrin were significantly(P＜0.05) increase and decreased respectively. The silkworms fed with 1.08 ng/L cypermethrin, the mortality of silkworms, and larval weight during moult and cocoon weight was significantly (P＜0.01) increase and decreased respectively. The influence of 10.80 ng/L cypermethrin on cocoon shell ratio was also significantly (P＜0.01) decreased.