[Comparison of molluscicidal effects of two snail control methods with plastic film covering in hilly regions].
OBJECTIVE
To evaluate and compare the molluscicidal effects of colorless and black plastic film covering methods against Oncomelania hupensis snails in hilly regions.


METHODS
A hilly setting with high snail density was selected as the study area, and three groups including the colorless plastic film covering method, black plastic film covering method and control were designed. The snail surveys were conducted 1, 3, 7, 15 days and 30 days in each group following plastic film covering, and the mortality of snails and reduction of snail density were investigated. The air temperature, soil surface temperature in the control group, as well as the soil surface temperature and the temperatures 5 cm and 15 cm under the soil within the film were recorded.


RESULTS
The mortality rates of snails were 36.84%, 78.94%, 95.92%, 100.00% and 99.45% 1, 3, 7, 15 days and 30 days following colorless plastic film covering, respectively, and the snail density after 30 days of covering reduced by 99.36% as compared to that before covering, while the mortality rates of snails were 10.08%, 8.94%, 6.11%, 26.15% and 49.32% 1, 3, 7, 15 days and 30 days following black plastic film covering, respectively, and the snail density after 30 days of covering reduced by 58.10% as compared to that before covering. There were significant differences in the 1-, 3-, 7-, 15-day and 30-day snail mortality rates between the colorless and black film covering groups (all P values <0.01), and a significant difference was detected in the snail density between the two groups 30 days after the film covering (P < 0.001). In addition, the speed, amplitude and duration of the rise in the soil surface temperature within the colorless film were all greater than those within the black film.


CONCLUSIONS
The short-term molluscicidal effect of the colorless plastic film covering method is significantly superior to that of the black plastic film covering method in summer in hilly regions.
Jiangning District Centre for Disease Control and Prevention, Nanjing City, Jiangsu Province, Nanjing 211100, China.
Yun
Y
Zhou
Jiangning District Centre for Disease Control and Prevention, Nanjing City, Jiangsu Province, Nanjing 211100, China.
Biao
B
Zhang
Jiangning District Centre for Disease Control and Prevention, Nanjing City, Jiangsu Province, Nanjing 211100, China.
Zhi-Mei
ZM
Wang
Jiangning District Centre for Disease Control and Prevention, Nanjing City, Jiangsu Province, Nanjing 211100, China.
Jia-Huei
JH
Zhao
Jiangning District Centre for Disease Control and Prevention, Nanjing City, Jiangsu Province, Nanjing 211100, China.
Shu
S
Mao
Tangshan Health Community Center, Jiangning District, Nanjing City, Jiangsu Province, China.
De-Bing
DB
Xie
Tangshan Health Community Center, Jiangning District, Nanjing City, Jiangsu Province, China.
Zhi-Zhong
ZZ
Mei
Tangshan Health Community Center, Jiangning District, Nanjing City, Jiangsu Province, China.
Jun
J
Zhang
Jiangsu Institute of Parasitic Diseases, China.
Qing-Biao
QB
Hong
Jiangsu Institute of Parasitic Diseases, China.
Wei
W
Wang
Jiangsu Institute of Parasitic Diseases, China.
Le-Ping
LP
Sun
D000818:Animals; D008975:Molluscacides / Q000494:pharmacology*; D010571:Pest Control / Q000379:methods*; D010969:Plastics / Q000494:pharmacology*; D011156:Population Density; D012908:Snails / Q000187:drug effects* / Q000254:growth & development; D013696:Temperature
D008975:Molluscacides; D010969:Plastics