Observation on frequency and effect of dusting molluscicide in irrigation canals / 中国血吸虫病防治杂志

ABSTRACT

Objective To study a new method and technical specification for Oncomelania snail control in irrigation canals.Methods Four percent niclosamide ethanolamine salt dustable powder was dusted in a test canal three times continuously,and a control canal was set up at the same time.The molluscicidal frequency and effect of niclosamide ethanolamine salt powder was observed and the results,including the change of living snail frames,average density of living snails and mortality of snails,were analyzed.Results Between the third and fifteenth day after the first dusting in the test canal,the reduction rate of the density of snails was more than 90% and after the second and third dusting,the reduction rate was more than 99%.For the average rates of living snail frames and mortality of snails,there were significant differences between the first dusting and later two dustings,while there was no significant difference between the second dusting and the third dusting.On the thirtieth and ninetieth day after the third dusting,the effect of snail control was still satisfactory.There were significant differences between the test canal and control canal about all the observation indexes.Conclusion The application of 4% niclosamide ethanolamine salt dustable powder is efficient in the snail control in irrigation canals,and the suitable frequency of dusting is 2 or 3 times.