Impact of water quality and soils on the molluscicidal activity of the plants A gave attenuata and A gave fihifera

ABSTRACT

The effect of water quality, salinity, an organic compound [Na[2]EDTA] and soil types [alluvial and sandy] on the molluscicidal activity of the two plants A gave attenuata and A gave filjfera against Biomphalaria alexandrina snails under laboratory conditions were studied. The LC[50] of the two tested plant molluscicides against B. alexandrina in all tested water samples [Nile, irrigation and drainage water] were lower than the tap water [as a control]. Thus, the molluscicidal activity of the two plants slightly increased when tested at the studied water samples. LC[50] values of the plant A. altenuata against B. alexandrina for the Nile water and drainage water were 50 and 54.5 ppm, respectively compared to 68 ppm for tap water. The corresponding values of A. fiIfera were 50, 54.5 and 60 ppm respectively. The molluscicidal activity of the two tested plants was not affected by the salinity levels used. Slight effect of the organic compound Na[2]EDTA on the molluscicidal activity of the two plants was recorded. However, the tested soils [alluvial and sandy] had a significant reduction in molluscicidal activity of A. attenuata and A. filifera against B. alexandrina. Thus, only 20% mortality of treated snails was recorded for LC[50] of A.attenuata in the presence of sandy soil, while no death was observed at alluvial soil. TLC analysis reveled only three bands for A. alt enuata mixed with sandy or alluvial soil compared to 6 bands for the crude plant. For A filifera only two bands appeared by mixing with sandy soil, whereas with alluvial soil no bands appeared