两种塑料地膜在血吸虫病水网型流行区的灭螺效果评价

Evaluation of molluscicidal effect of two kinds of plastic films in water network endemic areas of schistosomiasis

目的了解地膜覆盖法在血吸虫病水网型流行区不同时期的灭螺效果。方法在钉螺密度较高的地方(滋生地)选取3个监测点,在每个观察点投放7袋装有100只活钉螺的效应螺袋,然后予以不同覆膜的处理(黑色地膜组、无色地膜组以及对照组)。在效应螺投入后第1、3、7、15、30、60和90天分别回收效应螺袋,冲洗后分别对袋中的效应螺进行计数,并观察钉螺死活情况,同时利用自动化装置收集观察期间黑色地膜组、无色地膜组以及对照组膜内的温度。结果7批次回收3个观察点(黑色地膜组、无色地膜组和对照组)效应螺总回收率分别为98.14%(687/700)、98.57%(690/700)和97.57%(683/700)。在钉螺死亡状况方面,对获取不同天数后的效应螺进行分析,研究发现黑色地膜组与无色地膜组效应螺死亡率均随膜覆盖天数的延长,死亡率均呈升高趋势(黑色地膜组:χ2=314.28,P<0.001;无色地膜组:χ2=368.97,P<0.001),且均能达到100.00%的灭螺效果。在温度方面,当外界气温较高时,黑色地膜组与无色地膜组膜内均能保持长时间(9~18时)的较高温度,黑色地膜组与无色地膜组的温度变化较对照组差异有统计学意义(无色地膜组vs.对照组:t=13.94,P<0.001;黑色地膜组vs.对照组:t=11.94,P<0.001),且黑色地膜组与无色地膜组差异亦有统计学意义(t=9.336,P<0.001)。高温是覆膜灭螺的一个重要原因,无色地膜组的灭螺效果优于黑色地膜组可能与膜内温度有一定的关系。黑色地膜组的膜内无杂草生长且覆膜无破损,而无色地膜组的膜内杂草丛生且造成无色地膜破损。结论黑色地膜覆盖法在血吸虫病水网型流行区的有螺环境中进行灭螺处理,具备较好的优势与效果。

Objective To understand the effects of oncomelania snail eradication in different periods with plastic films mulching in water-net-endemic areas of schistosomiasis.Methods In this study,3 monitoring points were selected in places with high snail density,and 7 bags each containing 100 live snails were placed at each observation point,and then treated with different films(black mulch film group,colorless mulch film group and the control group).The effect snail bags were recovered on the 1,3,7,15,30,60 and 90 days after the snails were put in.After washing and other treatments,the snails in the bags were counted.At the same time,an automatic device was used to collect the air temperature in the black mulch film group,colorless mulch film group and the control group during the observation period.Results The total recovery rates of snails in black mulch film group,colorless mulch film group and control group were 98.14%(687/700),98.57%(690/700)and 97.57%(683/700),respectively.The mortality of the snails in the black mulching film group and the colorless mulching film group increased with the extension of the film coverage days,and the mortality rate showed an increasing trend(Black mulch film group:χ2trend=314.28,Ptrend<0.001;Colorless mulch film group:χ2trend=368.97,Ptrend<0.001)and all could achieve 100.00%snail control effect.In terms of temperature,when the outside temperature was high,both the black mulch film group and the colorless mulch film group could maintain a high temperature for a long time(from9:00 to 18:00).The paired t-test results showed that the temperature changes between the black mulch film group and the colorless mulch film group were significantly different from those of the control group(colorless mulch film group vs.control group:t=13.94,P<0.001,black mulch film group vs.control group:t=11.94,P<0.001)and there were also significant differences between the black mulch film group and the colorless mulch film group(t=9.336,P<0.001).This result suggests that high temperature might be an important reason for snail control and the colorless film group had better snail control effect than black film,and temperature inside the film might play an important role.However,when observing the different treatment groups,the study found that the black mulching film group had no weeds growing and the mulching film was not damaged,while the colorless mulching film group was overgrown with weeds and the mulching film was damaged to a certain extent by the weeds.Conclusion In terms of comprehensive anti-snail effects and maintenance after corresponding measures,the black mulching method had better advantages and effects on snail-killing in water-net-endemic areas of schistosomiasis.