2种有机磷类杀蚊幼剂现场灭蚊幼实验研究

目的了解甲基嘧啶磷、毒死蜱在灭蚊幼中的效果及持效期,为今后防治蚊幼提供依据。方法选择试验现场后测量水体体积,分别施药,并在施药前后用勺捕法进行密度测定,评价效果。结果分别施于污水沟、苇塘剂量为0.2、0.4 g/m3的甲基嘧啶磷对蚊幼杀灭率达75%,可分别维持13、28 d;施于苇塘剂量分别为0.5、1 g/m3的毒死蜱对蚊幼杀灭率达100%,可分别维持66、69 d;使用后者剂量施于污水坑,在投药后1~68 d、70 d其杀灭率分别为95.34%~100%、79.91%。结论实验初步验证毒死蜱对蚊幼杀灭效果及持效期优于甲基嘧啶磷。两者均为优良的杀幼剂。在实际现场灭蚊幼中可根据环境、特点、水体污染状况等选择适宜的杀虫药剂和使用剂量。

Efficacy of two kinds of organophosphorus insecticide against mosquito larvae in field

Objective To observe the efficacy and residual activity of pirimiphos-methyl, chlopyrifos against larvae of Culex pipiens paUens in field and provide scientific data for controlling mosquito larvae in future. Methods The experimental site（ including treatment and control area） were selected and the volume of water body were measured, then insecticides were sprayed respectively into the experiment spot. The density assessment was carried out periodically with the ladle catches method in treatment and control area before and after treatment. Results Applied pirimiphos-methyl （0. 2 g/m^3 in sewage pit,0.4 g/m^3 in reed pond）for controlling mosquito larvae, the killing rate was 75% ,the residual activity days were 13 d and 28 d respectively. Applied chlopyrifos （0. 5 g/m^3 and 1 g/m^3 in reed pond）for controlling mosquito larvae, the days of residual activity were 66 d and 69 d respectively at the 100% killing rate. 0. 4 g/m^3 in sewage pit,the killing rate were from 95.34% to 100%and 79.91% respectively after treatment for 1 - 68 d and 70 d. Conclusion The efficacy and persistent activity of chiopyrifos against mosquito larvae was better than pirimiphos-methyl. But they are good larvieides for controlling mosquito larvae. To control mosquito larvae in field, the suitable larvicides and application dosages should be applied according to environment, characteristics and the pollution condition of water body.