[Molluscicidal effect of spraying 5% niclosamide ethanolamine salt granules with drones against in marshland areas].

OBJECTIVE

To evaluate the molluscicidal effect of spraying 5% niclosamide ethanolamine salt granules with drones against of snails in snail habitats in marshland areas.

METHODS

From September to October, 2022, marshlands were sampled from Dantu District, Zhenjiang City, Jiangsu Province as study areas, and assigned into four groups, of approximately 3 000 m per group. In Group A, environmental cleaning was performed, followed by spraying 5% niclosamide ethanolamine salt granules with knapsack sprayers at a dose of 40 g/m, and in Group B, 5% niclosamide ethanolamine salt granules were sprayed with knapsack sprayers at a dose of 40 g/m without environmental cleaning, while in Group C, environmental cleaning was conducted, followed by spraying 5% niclosamide ethanolamine salt granules with drones at a dose of 40 g/m, and in Group D, 5% niclosamide ethanolamine salt granules were sprayed with drones at a dose of 40 g/m without environmental cleaning. Then, the study areas in each group were equally divided into six blocks, with Block 1 for baseline surveys and blocks 2 to 6 for snail surveys 1, 3, 5, 7, 14 days following chemical treatment. The mortality of snails and the reduction of the density of living snails were calculated.

RESULTS

A total of 132 frames were surveyed during the period from September to October 2022, and the occurrence of frames with living snails and means density of living snails were 61.36% (81/132) and 1.58 snails/0.1 m, respectively. The overall mortality rates of snails were 43.02% (77/179), 38.69% (77/199), 47.78% (86/180) and 31.02% (58/187) 14 days following chemical treatment in groups A, B, C and D, respectively (χ = 11.646, < 0.05), and there were differences detected in the snail mortality between group A and D, and between groups C and D (both values < 0.05). The adjusted mortality rates of snails were 37.42%, 36.07%, 38.85% and 40.40% in groups A, B, C and D 14 days post-treatment, and the density of living snails decreased by 48.10%, 63.29%, 67.09% and 69.62% 14 days post-treatment relative to pre-treatment, respectively.

CONCLUSIONS

Chemical treatment with drones is feasible for snail control in marshland areas; however, the molluscicidal effect of spraying 5% niclosamide ethanolamine salt granules with drones is comparable to spraying chemicals manually in marshland areas regardless of environmental cleaning.