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目的 :提高杀虫剂对致乏库蚊幼虫的药效。方法 :将氯氰菊酯与B .t.iH 14混配 ,观察对试虫的半数致死量 (LC50 )及共毒系数。结果 :混配制剂对敏感品系致乏库蚊幼虫的LC50 为0 .0 0 56mg/L ,共毒系数为90 .8;对抗性致乏库蚊幼虫的LC50 为 0 .0 545mg/L ,共毒系数为2 84 .0 3。按 2 .5mg/L浓度对敏感品系及抗性品系试虫的灭效 >80 % ,在实验室的持效时间为 2 1d ,2 1d后灭效迅速下降 ,30d药效基本丧失。结论 :该混配制剂对敏感品系试虫的毒力表现为两者相加作用 ,对抗性品系试虫有明显增效作用 ,持效期长于单独使用 0 .5mg/L氯氰菊酯及2 .0mg/LB .t .iH 14。
Objective: To improve the efficacy of insecticides on Culex pipiens larvae. Methods: Cypermethrin was mixed with B.t.iH 14 to observe the half lethal dose (LC50) and co-toxicity coefficient of the test insects. Results: The LC50 of Culex pipiens pallens larvae in the susceptible strain was 0.0056 mg / L and the co-toxicity coefficient was 90.8. The LC50 of Culex pipiens pallens larvae was 0 545 mg / L The poison coefficient is 2 84 .0 3. According to the concentration of 2.5mg / L, the killing rate of sensitive strains and resistant strains was> 80%, the persistence time in the laboratory was 21 days, the killing effect dropped rapidly after 21 days, and the efficacy was basically lost after 30 days. CONCLUSION: The toxicity of the mixed preparation to the susceptible strain is additive, and the antagonistic strain has obvious synergistic effect. The persistence period is longer than that of 0.5 mg / L cypermethrin alone and 2.0 mg / LB .t. IH 14.