study on biological control of six fresh water snails of medical and veterinary importance

ABSTRACT

This study evaluated the molluscicidal effect of Commiphora molmol oil extract [Myrrh], on control of six fresh water snails [Lymnaea natalensis, Bilinus truncatus, Biomphalaria alexandrina, Physa acuta, Melania tuberculata and Cleopatra bulimoides]. Also, the extract effect on the egg masses of L. natalensis, B. truncatus, B. alexandrina and Ph. acuta was evaluated. Snails and egg masses were exposed at 16-20°C to various concentrations [conc.]- LD[50] after 24 hours exposure were 264/132, 283/195, 230/252, 200/224, 241/246 and 241/246 ppm for young/adult of L natalensis, B. truncatus, B. alexandrina, Ph. acuta, M. tuberculata and C. bulimoides respectively. LD[100] after 24 hours exposure were 400/400 for L. natalensis, B. truncatus, B. alexandrina, M. tuberculata and C. bulimoides, and 300/300 for Ph. acuta. Also, complete mortality [100%] was achieved for the egg masses of L. natalensis, B. truncatus, B. alexandrina and Ph. acuta at concentrations of 300, 200, 300 and 400 ppm respectively. Lower concentrations gave the same results after longer exposure. LD[100] of C. molmol oil extract [Myrrh] had a rapid lethal effect on the six snail species and their egg masses in high conc, of 300 and 400 ppm. Commiphora molmol is a promising plant to be included with the candidate plant molluscicides. The oil extract of this plant showed a remarkable molluscicidal activity against used snail species