关键词: 钉螺； 螺威； 氯硝柳胺乙醇胺盐； 杀螺效果； 植物杀螺剂； 现场评价

Abstract: Objective To evaluate the field effect of the plant molluscicide“Luo?wei” （tea?seed distilled saponins，TDS） against the snail Oncomelania hupensis in the river beach in Anhui Province. Methods The immersing and spraying experiments were carried out in the river beach in Dongzhi County，Anhui Province，to assess the molluscicidal effect of 4% TDS comparing with 50% wettable powder of niclosamide ethanolamine salt（WPN） . The χ2 test or Fish’ s exact test was used to examine the dif? ferences between or among the molluscicidal effects by different environments，molluscicides，application methods，or days after the intervention. Meanwhile，the cost?effectiveness of the two molluscicides was analyzed. Results After 1，2 ，3 d and 7 d of the immersion，the snail death rates in both TDS group and WPN group increased gradually，the snail death rates in the two groups af? ter immersing for 7 d were 94.62% and 99.24%，respectively，and there was no significant difference between them（χ2 =3.30， P > 0.05） . After 1 ，3 ，7 d and 15 d of spraying，the snail death rates were 70.82%，79.75%，85.11% and 91.65% in the TDS group，and 77.71%，84.27%，91.90% and 95.58% in the WPN group，respectively，and the differences among the snail death rates of the two groups at each time point were statistically significant（all P values < 0.05） . The costs of spraying were 316.71 yu? an per 100 m2 for TDS and 309.71 for WPN. Conclusions The molluscicidal effect of TDS has reached the requirements of na? tional standard on nature source pesticides in the river beach of the middle and lower reaches of the Yangtze River. It is necessary to further evaluate its cost?effectiveness in large?scale field experiments in the future

Key words: Oncomelania hupensis；Luo?wei（tea?seed distilled saponins, TDS）；Niclosamide ethanolamine salt（WPN）； Molluscicidal effect；Plant molluscicide；Field evaluation