三种有机磷杀虫剂对印鼠客蚤的灭效研究

目的 实验室测试乐斯本、辛硫磷、敌敌畏3种杀虫剂对印鼠客蚤的杀灭效果。方法 瓶膜法。结果 （1）3种杀虫剂半数致死浓度LG50乐为5．9615mg／L，LC50半为6．7873mg／L，LC50敌为7．8343mg／L。（2）敌敌畏浓度在100、200mg／L时的KT50分别为9．0和4．2min，24h死亡率均为100％；辛硫磷在这2个浓度的KT50分别为44．5和23．6min，24h死亡率分别为98．7％和9718％；乐斯本在这2个浓度的24h死亡率分别为98．9％和100％。（3）浓度为100、200mg／L时，敌敌畏18min的击倒率分别为94．5％和100％，辛硫磷17min的击倒率分别为24．4％和41．1％。（4）残效：在浓度为50、100、200mg／L时，辛硫磷30d残效30min无击倒，24h死亡率为0；敌敌畏30d残效24h死亡率分别为0、16.7％、31．0％，效果较差。结论 3种药物在同一浓度下的速杀作用效果敌敌畏〉辛硫磷〉乐斯本，可将速杀效果好的与残效作用好的杀虫剂混配用于灭蚤。

Studies on the Toxicity of Three Organic Phosphates Insecticide to Xenopsylla cheopis

Objective To study the toxicity of chlorpyrifos,phoxim and dichlorvos to Xenospylly cheopis in laboratory.Methods The residual smearing method was used.Results (1) The LC_(50) of chlorpyrifos phoxim and dichlorvos to(X.cheopis) were(5.961 5 mg/L),(6.787 3 mg/L) and(7.834 3 mg/L),respectively.(2) At the concentration of 100 and(200 mg/L),the KT_(50) values of dichlorvos were(9.0 min) and(4.2) min and after treated for 24 hours both death rates were 100%,the KT_(50) values of phoxim were(44.5) min and(23.6) min,the 24 hours death rates were(98.7%) and(97.8%),while the death rates for chlorpyrifos tyeated 24 hours were(98.9%) and 100%.(3) When at the concentration of 100 and(200 mg/L),after 18 min the knock down rates of dichlorvos were(94.5%) and 100%,17 min treated the knock down rates of phoxim were(24.4%) and(41.1%).(4) At the concentration of 50,100 and(200 mg/L),the 24 hours death rates for 30 days residue effect of phoxim were 0,but for dichlorvos were 0,(16.7%) and(31.0%).For chlorpyrifos at the concentration of 400,800 and (1 600 mg/L),after 24 hours the death rates for 210 days were(55.2%),(75.0%) and(96.4%).Conclusion The quick toxitocy of the three insecticides to(X.cheopis) is dichlorvos>phoxim>chlorpyrifos.The residue effects are low.