密达利杀灭湖北钉螺效果的研究

目的 实验室和现场试验评价密达利（META-Li， 40%四聚乙醛水乳剂）杀灭湖北钉螺的效果。 方法 室内：采用泥缸喷洒法、烧杯浸杀法和三角沉淀杯上爬法，用敲击法观察不同时间、不同浓度密达利对湖北钉螺的杀灭和抑制上爬作用。现场：选择安徽省芜湖县草滩进行现场喷洒试验，密达利剂量为1、2和4 g/m²，设氯硝柳胺药物对照剂量为1 g/m²和清水空白对照组，观察施药后3、7和15 d检查钉螺存活情况。 结果 室内喷洒试验：24、48和72 h的半数致死剂量（LD₅₀）分别为0.78、0.44和0.46 g/m2；室内浸杀试验：24、48、72 h的半数致死浓度（LC₅₀）分别为44.4、27.4和24.8 mg/L；24 h抑制钉螺上爬半数有效浓度（EC₅₀）为5.86 mg/L。现场喷洒试验：密达利2 g/m2喷洒后7 d钉螺死亡率大于90%，灭螺效果和氯硝柳胺1 g/m²相当（P>0.05）。 结论 密达利室内及现场喷洒灭螺效果明显，有抑制钉螺上爬作用。

Study on the Molluscicidal Effect of META-Li Against Oncomelania hupensis

Objective To evaluate the molluscicidal effect of the META-Li(40% META liquid formulation) against Oncomelania snails in laboratory and field. Methods The experiment of META-Li against the snails by spraying, immersion and climbing-inhibition test was carried out in laboratory. Spray method was performed in the field to compare with the wettable powder of 50% niclosamide ethanolamine salt. Results In laboratory, the LC50 of META-Li by spraying for 1, 2, 3 days was 0.78, 0.44 and 0.46 g/m2 respectively; by immersion method for 1, 2, 3 days, it was 44.4, 27.4 and 24.8 mg/L respectively. When sprayed with active ingredient 2 g/m2 of META-Li in the field, the snail death rate was above 90% after 7 days, similar to that of niclosamide. Conclusion META-Li shows high molluscicidal and climbing-inhibition effect on Oncomelania snails.