Objective: To evaluate the molluscicidal effect of spraying different formulations of niclosamide ethanolamine salt with drones against Oncomelania hupensis in ditches.
Methods: A semi-dry and semi-wet ditch with O. hupensis snails was selected in the second branch field of Jiangbei Farm, Jiangling County, Hubei Province in May 2023, and divided into 4 experimental areas, named groups A1, A2, B1 and B2. Environmental cleaning was performed in groups A1 and B2, and was not conducted in groups A2 or B2. Then, 50% wettable powder of niclosamide ethanolamine salt was sprayed with drones at an effective dose of 2 g/m2 in groups A1 and A2, and 5% niclosamide ethanolamine salt granule was sprayed with drones at an effective dose of 2 g/m2 in groups B1 and B2. O. hupensis snails were surveyed using the systematic sampling method 1, 3, 5, 7, 14 days after spraying, and the natural mortality and corrected mortality of O. hupensis snails were calculated.
Results: The occurrence of frames with living snails, mean density of living snails and natural mortality of snails were 97.50% (117/120), 6.30 snails/0.1 m2 and 1.18% (9/765) in the test ditch before spraying, respectively. There were significant differences in the mortality of snails among four groups 1, 3, 5, 7 and 14 days after spraying niclosamide formulations with drones (χ2 = 17.230, 51.707, 65.184, 204.050 and 34.435, all P values < 0.01). The overall mortality rates of snails were 94.51% (1 051/1 112), 79.44% (908/1 143), 96.54% (977/1 012) and 88.55% (1 021/1 153) in groups A1, A2, B1 and B2 (χ2 = 207.773, P < 0.05), respectively. In addition, there was no significant difference in the overall snail mortality between groups A1 and B1 (P > 0.05), and the snail mortality in groups A1 and B1 were both statistically different from that in groups A2 and B2 (all P values < 0.05).
Conclusions: Both 50% wettlable powder of niclosamide ethanolamine salt and 5% niclosamide ethanolamine salt granule sprayed with drones are active against O. hupensis snails in ditches, and environmental cleaning may improve the molluscicidal effect.
［摘要］ 目的 评价应用无人机在沟渠环境施用不同剂型杀螺胺乙醇胺盐的灭螺效果。方法 2023年5月在湖北省荆 州市江陵县江北农场二分场选取1个半干半湿的有螺沟渠环境作为试验现场, 并划分为A1、A2、B1、B2等4个试验组地 块, 每组面积约500 m2。A1、B1组清障后, 分别采用无人机喷洒50%杀螺胺乙醇胺盐可湿性粉剂和5%杀螺胺乙醇胺盐 颗粒剂, 有效剂量均为2 g/m2; A2、B2组不清障, 分别采用无人机喷洒50%杀螺胺乙醇胺盐可湿性粉剂和5%杀螺胺乙醇 胺盐颗粒剂, 有效剂量均为2 g/m2。施药前1 d及施药后第1、3、5、7天和第14天, 通过系统抽样法进行钉螺调查, 采用压 碎法鉴别钉螺死活, 计算不同时间各组钉螺自然死亡率和校正死亡率。结果 施药前, 试验沟渠活螺框出现率为 97.50% (117/120), 活螺平均密度为6.30只/0.1 m2, 钉螺自然死亡率为1.18% (9/765)。无人机施药后第1、3、5、7、14天各 组钉螺死亡率差异均有统计学意义 (χ2 = 17.230、51.707、65.184、204.050和34.435, P均< 0.01) ; A1、A2、B1组和B2组钉螺总 死亡率分别为94.51% (1 051/1 112)、79.44% (908/1 143)、96.54% (977/1 012) 和88.55% (1 021/1 153), 差异有统计学意义 (χ2 = 207.773, P < 0.05); 经两两比较发现, A1、B1组钉螺总死亡率差异无统计学意义 (P 均> 0.05), 但均高于A2、B2组 (P 均< 0.05)。结论 在沟渠环境采用无人机喷洒50%杀螺胺乙醇胺盐可湿性粉剂与5%杀螺胺乙醇胺盐颗粒剂均可有效 杀灭钉螺, 施药前对环境进行清障可进一步提高灭螺效果。.
Keywords:
Drone; Granule; Niclosamide ethanolamine salt;