HL杀灭湖北钉螺效果观察

目的实验室和现场试验评价HL杀灭湖北钉螺的效果。方法实验室采用泥缸喷洒法、烧杯浸杀法和三角沉淀杯上爬法,观察不同浓度HL对湖北钉螺的杀灭和抑制上爬作用。选择在安徽省芜湖县草滩进行现场喷洒试验,HL剂量分别为40、80、120g/m2,以50%氯硝柳胺乙醇胺盐可湿性粉剂(2g/m2)为药物对照,另设清水为空白对照组,施药后3、7和15d检查钉螺存活情况。结果泥缸喷洒24、48和72h的半数致死浓度(LC50)分别为269、117、65g/m2。烧杯浸杀24、48和72h的LC50分别为115.4、10.6和9.9mg/L;24h抑制钉螺上爬半数有效浓度(EC50)为55.8mg/L。现场使用80g/m2HL喷洒15d钉螺死亡率为84%,40g/m3HL浸杀3d钉螺死亡率为80%。50%氯硝柳胺乙醇胺盐可湿性粉剂2g/m2喷洒15d钉螺死亡率为91%,2g/m3浸杀3d钉螺死亡率为100%。结论HL室内及现场对钉螺均有较好的杀灭效果。

Molluscicidal effect on the plant molluscicide HL against Oncomelania hupensis

The molluscicidal effect of the plant molluseicide HI. to Oncomelania hupensis in laboratory and field investi- gation. In laboratory experiment, effect of HL was performed by spray, immersion and climbing test to observe the inhibitory effect of HL on the climbing action of snails. The field spray investigation was done in Wuhu of Anhui province by spray with different concentration of HL （40, 80 and 120 g/m2 ;and 50% of niclosamide powder （2 g/m2） and pure water were used as the drug control and blank control. The surviving condition of snails was examined 3, 7 and 15 days after application of medicines. It was found that the 50% lethal concentration （LC50） of HL used in spray method for 24, 48 and 72 hours were 269, 117 and 65g/m2） respectively, while by using the immersion method, they were 115.4, 10.6 and 9.9 mg/L. The 50% effec- tive concentration （EC50） of HL to inhibit the climbing of snails 24 hours after usage of drug was 55.8 mg/L. In addition, the death rate of snails sprayed with 80 g/m2 of HL 15days after spraying was 84% , and that of the immersion method using 40 g/ m2 of HL for 3 days was 800/00. As to the drug control groups, they were 91% for spray of niclosamide for 15 days and 100% for water immersion for 3 days. From these observations it is evident that plant molliscicide HL has molluscicidal effect on Oncomelania hupensis.