ABSTRACT
Objective To investigate the effectiveness and cost of 50% and 80% wettable powder of niclosamide ethanolamine salt (NESWP) and 26% metaldehyde and niclosamide suspension concentrate (MNSC) in hilly schistosomiasis-endemic regions, so as to provide insights into the selection of chemical molluscicides in hilly regions. Methods In September 2020, a wasteland in Guanshanqiao Village, Yanrui Township, Yushan County of Jiangxi Province was selected as the experimental region, which was sectioned into five blocks and defined as four experimental groups (A1, A2, B, C) and a blank control group (D). 80% NESWP were given at doses of 1 g/m2 and 1.5 g/m2 in groups A1 and A2 using the spraying method, 50% NESWP was given at a dose of 2 g/m2 in Group B using the spraying method, and 26% MNSC was at a dose of 4 g/m2 in Group C using the spraying method, while no chemical treatment was given in Group D. Snail survey was performed using a systematic sampling method before chemical treatment and 1, 3, 7 d and 15 d post-treatment to examine the molluscicidal effect, and all molluscicidal costs were estimated to calculate the cost of chemical treatment per 1 m2 and the cost of the reduction in the mean density of living snails per 1%. Results The highest mortality of snails was 78.95% and the lowest density of living snails was 0.2388 snails/0.1 m2 in the experimental groups within 7 d of chemical treatment, and the highest mortality of snails was 94.74% and the lowest density of living snails was 0.058 0 snails/0.1 m2 7 d post-treatment. There were no significant differences in the snail mortality among the A1, A2, B and C groups 1 (χ2 = 2.250, P > 0.05), 3 (χ2 = 1.779, P > 0.05) or 15 d post-treatment (χ2 = 2.286, P > 0.05), while a significant difference was detected in the snail mortality among the four groups 7 d post-treatment (χ2 = 7.990, P = 0.046). In addition, there were no significant differences in the snail mortality between A1 and A2 groups 1 (χ2 = 0.724, P > 0.05), 3 (χ2 = 0.584, P > 0.05), 7 (χ2 = 0.400, P > 0.05) or 15 d post-treatment (χ2 = 0.251, P > 0.05). The costs of chemical treatment per 1 m2 were 0.58, 0.60, 0.64 Yuan and 0.73 Yuan in groups A1, A2, B and C, and the costs of the mean density of living snail per 1% reduction were 19.29, 20.44, 21.68 Yuan and 23.53 Yuan in groups A1, A2, B and C, respectively. Conclusion 80% NESWP shows a high molluscicidal efficacy and low cost in hilly schistosomiasis-endemic regions.
ABSTRACT
Objective To evaluate the effects of 3 molluscicides namely 5%niclosamide ethanolamine granules,4%“Luo-wei”(Tea-seed distilled saponins,TDS)and 50%wettable powder of niclosamide ethanolamine salt(WPN)by spraying and pou-drage methods in marshland and lake regions in dry season. Methods 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 differ-ent time. Results 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. Conclusion 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.
ABSTRACT
Objective To compare the field molluscicidal effects of 25%suspension concentrate of nielosamide ethanolamine salt(SCNE),50% wettable powder of niclosamide ethanolamine salt(WPN),40% META-Li and 50% Rongbao powder,so as to provide scientific basis for choosing the safe and highly effective molluscicide in field.Methods Four snail habitats with the similar snail status were selected and sprayed with the four molluscicides mentioned above,respectively.Then the snail status in the four fields was surveyed 3,7 and 17 d after the spraying and the moiluscicidal effects of difierent molluscieides were cornpared.Results The corrected mortalities of snails in the field sprayed with SCNE 3,7 and 17 d afterthe spraying were the hiishest among the four fields,with the rates of 93.13%,91.85% and 85.28%,respectively.Conclusion SCNE has a high molluseieidal effect in the field and can be further used in snail-infested areas.
ABSTRACT
In order to evaluate the moUuseicidal effect of 50% wettable power of niclosamide ethanolamine salt(WPN)combined with urea against Oncomelania snails in the field,4 g/m~2 WPN,4 g/m~2 WPN+20 g/m2 urea and 4 g/m~2 WPN+30 g/m~2 urea were used for mollusciciding with the spraying method.The results showed after 7 days,the mortality rates of snail were 74.43% for 4 g/m~2 WPN,90.32% for 4 g/m~2 WPN+20 g/m~2 urea and 94.83% for 4 g/m~2 WPN+30 g/m~2 urea,respectively.It is indicated that WPN combined with urea can improve the molluscieidal effect significantly.
ABSTRACT
Objective To evaluate the molluscicidal effect of 2 kinds of shamingdan in lab. Methods Under constant temperature (25?1) ℃, the studies were carried out by using different concentrations(dosages) of molluscicide, shamingdan, in various methods of immersing, spraying and dusting power, and the molluscicidal effects were compared with 50% wettable powder of niclosamide ethanolamine salt(WPN). Results The 48-hour's LC_ 50(s) of 4% shamingdan granular formulation and 50% shamingdan soluble powder were 0.1752 mg/L and 0.2713 mg/L, respectively, which were similar to that of 50% WPN. In spraying and dusting powder experiment, the 7-day's LC_ 50(s) were 3.0418, 0.1623 g/m~2 and 2.8752, 1.1101 g/m~2, respectively, and the 50% shamingdan soluble powder was better than 4% shamingdan granular formulation and 50% WPN. Conclusions The molluscicidal effect of 2 kinds of shamingdan using immersing is better than that using spraying and dusting. The molluscicidal effect of the 50% shamingdan soluble powder is remarkably better than that of the 4% shamingdan granular formulation and 50% WPN.