[Field evaluation of a novel plant molluscicide "Luo-Wei" against Oncomelania hupensis I molluscicidal effect by the spraying method in lake and marshland regions].

OBJECTIVE

To evaluate the field effect of a novel plant molluscicide "Luo-wei" (Tea-seed distilled saponins, TDS) against Oncomelania hupensis in the lake and marshland regions.

METHODS

A spraying experiment was carried out in the grassland of two schistosomiasis endemic counties, including Xingzi in Jiangxi Province and the Huarong in Hunan Province, to assess the molluscicidal effect of 4% TDS comparing with 50% wettable powder of niclosamide ethanolamine salt (WPN). The chi2 test was used to examine the differences between regions, molluscicides, or days after spraying.

RESULTS

Following 1, 3, 7, and 15 days of test, the snail mortality showed a simultaneous increase both in TDS group (70.43%-86.88%) and WPN group (70.21%-85.35%). There is no significant difference between TDS and WPN of day 1, 7 and 15 (all P values > 0.05), but except for day 3 (chi2 = 3.910, P = 0.048). By the end of day 15, the snail mortality for TDS was 86.53% in Xingzi and 88.28% in Huarong, while for WPN was 83.04% in Xingzi and 93.69% in Huarong respectively; the decline rate of snail density for TDS was 85.29% in Xingzi and 93.53% in Huarong, while for WPN was 85.29% in Xingzi and 93.53% in Huarong respectively. The adjusted mortality of different days ranged from 69.63% to 86.54% in the the TDS group, and 69.41% to 86.54% in the WPN group.

CONCLUSION

The molluscicidal effect of TDS by spraying is similar to that of WPN. It is time to popularize this new plant molluscicide (TDS) in a wider field.