Molluscicidal activities of certain pesticide and their mixtures against Biomphalaria alexandrina

In this study, Biomphalaria alexandrina snails were collected from irrigation canals at Giza Governorate and maintained on fresh lettuce leaves under suitable laboratory conditions. Niclosamide and uccmaluscide proved to be the most effective compounds, followed by copper sulfate. This was followed by anilofos, isoprothiolane and fluazifop-P-butyl. Moreover, butachlor herbicide was the least potent compound. In general, the specific molluscicides showed more efficiency than the conventional tested herbicides and fungicides on the treated snails. Pre-exposure to 1/10 LC50 of anilofos, butachlor and isoprothiolane showed synergistic effects to uccmaluscide. However, the same treatment with 1/10 LC50 of fluazifop-P-butyl, isoprothiolane and butachlor gave an additive effect to copper sulfate and niclosamide on the treated snails. Data indicated that when butachlor, anilofos, fluazifop-P-butyl or isoprothiolane added to copper sulfate at ratios of 10:40 and 20:30 of LC50 as well as anilofos when added to copper sulfate at 30:20 showed synergism in activity against snails. On the contrary, the tested mixtures with niclosamide resulted in an antagonistic action, while they showed synergistic effect. Isoprothiolane-uccmaluscide mixture at a ratio of 40:10 of LC50 showed an additive effect on the snails. The determination of niclosamide by gas chromatography indicated that niclosamide showed relatively slower degradation either in case of niclosamide or its mixture with butachlor. Meanwhile, its mixture with anilofos or fluazifop-p-butyl or isoprothiolane showed a rapid degradation