[Molluscicidal effect of suspension concentrate of niclosamide ethanolamine salt]

Objective To evaluate the molluscicidal effect of suspension concentrate of niclosamide ethanolamine salt (SCNE) against Oncomelania hupensis snails in laboratory and field. Methods The experiment of SCNE against the snails by using the immersing and spraying methods was performed in laboratory and field, with control groups of wettable powder of niclosamide ethanolamine salt (WPN). Results In the laboratory, LC_50(s) of SCNE for 24, 48 h and 72 h by using the immersion method were 0.092 6, 0.062 9 mg/L and 0.054 9 mg/L, respectively. The mortality rates of snails for 24, 48 h and 72 h by using the immersion method were all 100% with the concentrations of 0.25 mg/L. The mortality rates of snails were all 100% while spraying SCNE for 3 d in the laboratory with the concentrations of 0.25 g/m². In Jiangling County, except 0.5 g/m³ SCNE immersing the snails for 24 h, the mortality rates of snails by using SCNE with the immersing method were all 100%. While the concentration of SCNE was 0.5 g/m³ or above, the mortality rates were all 100% after the use of it with the immersion method for 2 d in Gong'an County. In Jiangling County, the mortality rates of snails by using SCNE 0.5 g/m³ for 1 d, 3 d, and 7 d with the spraying method were 87.5%, 92.82% and 97.40% respectively. While the concentration of SCNE was 0.5 g/m³, the mortality rates were 85.94%, 86.78% and 94.21% respectively after the use of it with the spraying method for 1 d, 3 d, 7 d in Gong'an County, and the molluscicidal effect of SCNE (1.0 g/m²) was higher than that of WPN. Conclusion SCNE has a high molluscicidal effect in the laboratory and field, and it is a novel and simple formulation of niclosamide.