[Field evaluation of a novel plant molluscicide "Luo-wei" against Oncomelania hupensis IV molluscicidal effect in field of river beach in Dongzhi County, Anhui Province].
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 chi(2) test or Fish's exact test was used to examine the differences 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 after immersing for 7 d were 94.62% and 99.24%, respectively, and there was no significant difference between them ( chi(2) = 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 yuan per 100 m2 for TDS and 309.71 for WPN.


CONCLUSIONS
The molluscicidal effect of TDS has reached the requirements of national 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.
Dongzhi Station of Schistosomiasis Control, Anhui Province, Chizhou 247230, China.
Fa
F
Shu
Dongzhi Station of Schistosomiasis Control, Anhui Province, Chizhou 247230, China.
Sheng-You
SY
Chen
Dongzhi Station of Schistosomiasis Control, Anhui Province, Chizhou 247230, China.
Wei-Ping
WP
Xie
Dongzhi Station of Schistosomiasis Control, Anhui Province, Chizhou 247230, China.
Ping
P
Zhou
Jiangsu Institute of Schistosomiasis, China.
Le-Ping
LP
Sun
National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, WHO Collaborating Center for Malaria, Schistosomiasis and Filariasis, Key Laboratory of Parasite and Vector Biology, Ministry of Health, China.
Tie-Wu
TW
Jia
D000818:Animals; D002681:China; D003362:Cost-Benefit Analysis; D004197:Disease Reservoirs; D008975:Molluscacides / Q000494:pharmacology*; D009534:Niclosamide / Q000494:pharmacology; D045483:Rivers; D012503:Saponins / Q000494:pharmacology*; D012908:Snails / Q000187:drug effects*
D008975:Molluscacides; D012503:Saponins; D009534:Niclosamide