Objective: To evaluate and compare the short-term effects of two kinds of plastic mulch on Oncomelania hupensis snail control in irrigation and drainage ditches with snails in Yunnan Province.
Methods: The irrigation and drainage ditches with high density of Oncomelania hupensis snails were chosen as the investigation sites, and then 4 groups were set, namely a colorless plastic mulch group, black plastic mulch group, colorless plastic mulch with molluscicide group and black plastic mulch with molluscicide group. The snail situation of the 4 groups was surveyed before the experiment and 7, 14, 21, 30 days after covering plastic mulch, and the snail death rates were compared among the 4 groups. Meanwhile, the hourly temperatures of soil surface, soil surface under plastic mulch and soil layer 5, 15 cm under the surface as well as the weather situation during the study period were measured and recorded.
Results: The average snail mortality rate of the colorless plastic mulch group was only 15.29% that was higher than that of the black plastic mulch group (6.56%) (P < 0.01). The average snail mortality rates of the colorless and black plastic mulch with molluscicide groups were 40.80% and 50.15%, respectively, and there was no statistic difference between them (P > 0.05). Both kinds of plastic mulches could raise the temperature of the soil surface under plastic mulch and the soil layer below it, and the temperature of soil under the mulches increased over the cover time, and the average temperature of the soil surface under the black mulch in 30 days was higher than that under the colorless mulch.
Conclusions: It is not suitable to use plastic mulch only in irrigation and drainage ditches with snails widely in Yunnan Province because of its low effect, and if necessary, the molluscicide should be added.
[摘要]目的 观察并比较无色和黑色塑料地膜覆盖法在云南省有螺排灌沟的短期灭螺效果。方法 选择钉螺密度较 高的排灌沟, 设单纯无色地膜覆盖组、单纯黑色地膜覆盖组、无色地膜覆盖施药组和黑色地膜覆盖施药组4个组。在实 验前以及覆盖地膜后7、14、21、30 d对各组进行螺情调查, 观察钉螺死亡率, 并定时记录土表温度、膜内土表及土下5、15 cm处温度及每日天气情况。结果 单纯无色地膜覆盖组钉螺平均死亡率 (15.29%) 略高于单纯黑色地膜覆盖组 (6.56%) (P < 0.01), 两组灭螺效果均不理想。两种地膜覆盖并辅以灭螺药, 均能增加钉螺死亡率; 无色、黑色地膜施药覆盖组钉 螺平均死亡率分别为40.80%、50.15%, 差异无统计学意义 (P > 0.05)。两种塑料地膜均能提高膜内土表及土内温度, 并 且随着覆盖时间的延长膜内土壤温度均呈升高趋势, 黑色地膜覆盖后30 d平均膜内土表温度高于无色地膜。结论 云 南省有螺排灌沟不宜大范围使用地膜覆盖法灭螺, 如必须使用地膜, 需辅以灭螺药物。.
Keywords: Irrigation and drainage ditch; Niclosamide; Plastic mulch; Schistosomiasis; Snail control effect; Yunnan Province.