[Molluscicidal effects of 3 molluscicides by spraying and poudrage methods in dry season]

To evaluate the effects of 3 molluscicides namely 5% niclosamide ethanolamine granules, 4% "Luowei" (Tea-seed distilled saponins, TDS) and 50% wettable powder of niclosamide ethanolamine salt (WPN) by spraying and poudrage methods in marshland and lake regions in dry season.

An environment with a high snail density was chosen as the experimental field, then the spraying and poudrage experiments were carried out in the field to assess the molluscicidal effects of 5% niclosamide ethanolamine granules, TDS and WPN delivered by spraying and poudrage methods with a concentration of 30, 6 and 2 g/m2, respectively, and the molluscicidal effects of the 3 drugs by the two methods were evaluated and compared in different time.

After the delivery for 15 d, the adjusted snail death rates of the 5% niclosamide ethanolamine granules, TDS and WPN in the spraying experiment were 79.00%, 82.29% and 84.83%, respectively, and those in the poudrage experiments were 97.42%, 95.27% and 96.62%, respectively.

The molluscicidal effect of poudrage method is better than the spraying method, and the former is worthy of further extension and application in the marshland in dry season.