Molluscicidal and cercaricidal efficacy of Acanthus mollis and its binary and tertiary combinations with Solanum nigrum and Iris pseudacorus against Biomphalaria alexandrina.

Abstract

Molluscicidial activity of leaves of Acanthus mollis against Biomphalaria alexandrina were evaluated. Its petroleum ether extract (LC50 values = 6.92 mg/L) was more potent than Solanum nigrum and Iris pseudacorus extracts. A binary combination (1:1) of A. mollis and S. nigrum, as well as, a binary combination (1:1) of A. mollis and I. pseudacorus extracts showed additive effect on snails (24 hr LC50: 5.09 mg/l and 3.76 mg/l respecttively). A tertiary combination (1:1:1) of A. mollis, S. nigrum and I. pseudacorus extracts (24 hr LC50: 4.01 mg/l) showed good result. Also, petroleum ether extract of A. mollis leaves killed Schistosoma mansoni cercariae at concentrations of 20, 10 and 5 mg/l within 30, 45 min. and an hour respectively. Mortality increased with increasing exposure time and concentration.