关键词: 乐斯本, 辛硫磷, 敌敌畏, 印鼠客蚤, 灭效

Abstract: 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 LC₅₀ 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 KT₅₀ values of dichlorvos were(9.0 min) and(4.2) min and after treated for 24 hours both death rates were 100%,the KT₅₀ 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.