Difference in the susceptibility to certain molluscicides and Schistosoma mansoni infection of three forms Egyptian Biomphalaria glabrata.

The first generation of 3 morphologically different forms of B. glabrata collected from Giza were compared for LC50 values susceptibility to bayluscide and copper sulphate (chemical molluscicides) and Anagallis arvensis and Calendula micrantha (plant molluscicides) and to Schistosoma mansoni infection. Form (2) as juvenile and adult were less sensitive to C. micrantha and A. arvensis. Form (3) as juvenile and form (1) as adult were least sensitive to CuSO4. Approximately the same susceptibility to bayluscide was observed in the 3 forms either as juvenile or adult. The sublethal concentrations of the molluscicides on B. glabrata 3 forms showed no significant difference in the growth or survival rate in between. Form (2) was significantly higher in the egg lying capacity. The total protein concentration was not affected except in certain cases where the increase was primarily due to the increase in the globulin concentrations which indicate with the marked increase observed in the urea concentration and marked increase or inhibition in the activity of either AST or ALT that the digestive gland of the 3 forms of snails is seriously affected by molluscicides. The 3 forms of B. glabrata showed low susceptibility to infection with the local strain of S. mansoni.

Molluscicidal activities of certain pesticide and their mixtures against Biomphalaria alexandrina.

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.