Molluscicidal effect of Piper guineense.

The study was undertaken to assess the dosage-mortality ratio and toxic effects of Piper guineense fruit extracts on the adults of Biomphalaria pfeifferi, the snail intermediate host of Schistosoma mansoni, which causes intestinal schistosomiasis. The result showed significant toxic effects with crude ethanol and hot water fruits extracts. The estimated lethal dose concentration by arithmetic method (LC(50) and LC(90)) using both crude ethanol and hot water fruit media extracts were found to be (0.10 ± 0.04, 0.9 ± 0.2) mgl(-1) respectively for ethanolic extract and (5.0 ± 1.4, 8.5 ± 0.7) mgl(-1) respectively for hot water extract. Ethanolic extract was more potent than hot water extract. An all or none phenomenon appeared characteristic of the biological activity of these extracts. There was significant decrease in oviposition rate (p < 0.02). The extract from the fruits of this tropical plant holds promise in the control of Biomphalaria pfeifferi.