The niclosamide and uccmaluscide proved to be the most effective compounds, followed by copper sulphate. The second category of efficiency includes the 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 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 additive effect to copper sulphate and niclosamide on treated snails. Data indicated that when butachlor, anilofos, fluazifop-P-butyl or isoprothiolane added to copper sulphate at the ratios of 10:40, 20:30 of LC50 as well as anilofos when added to copper sulphate at 30:20 showed synergism in activity against snails. On the contrary, the tested mixtures with niclosamide resulted in antagonistic action, while pesticide uccmaluscide mixtures showed synergistic effect, except isoprothiolane-uccmaluscide mixture at ratio 40:10 of LC50 showed additive effect on snails. Determination of niclosamide by gas chromatography, indicated that niclosamide showed relatively slower degradation either in the case of niclosamide or it's mixture with butachlor. Meanwhile, it's mixture with anilofos or fluazifop-p-butyl or isoprothiolane showed rapid degradation.