Influence of some natural and synthetic substances on certain fresh water organsisms and the snail vectors of Schistosomiasis and Fascioliasis

ABSTRACT

The effect of plants Anagallis arvensis, Calendula micrantha and Ambrosia maritima and the synthetic chemical molluscicides bayluscide and copper sulphate on survivorship, egg production of the snail vectors of schistosomiasis [Biomphalaria alexandrina] and fascioliasis [Lymnaea natalensis] and on some fresh water organisms were studied. Anagallis arvensis and Calendula micrantha showed good molluscicidal action against B. alexandrina and L. natalensis where LC90 values were 88 and 93 ppm, respectively, for A. arvensis and 135 and 100 ppm, respectively, for Calendula micrantha. The cumulative mortality of B. alexandrina [70%] was considerably high after 4 weeks of continuous exposure to A. arvensis. Complete inhibition of egg production was obtained for B. alexandrina after 2 weeks of exposure to low concentration of C. micrantha, bayluscide and copper sulphate. A. arvensis increased the maximum standing crops of algal biomass of Sirogyra [1.1358 g] and daily specific growth rate [0.0586 g.], while the control was 1.0106 g. and 0.0503 g., respectively. A low toxic effect on Daphnia pula was obtained under the effect of Anagul1is arvensis [5% mortality] and calendula micrantha [25% mortality] compared with synthetic molluscicides suggesting the use of the tested plants as molluscicides