Activity of the Molluscicidal Plant Millettia thonningii (Leguminosae) toward Biomphalaria glabrata Eggs

A dichloromethane extract of the seeds of the molluscicidal west African legume Millettia thonningii was tested for ovicidal activity toward Biomphalaria glabrata egg masses. The extract was found to be highly ovicidal at concentrations as low as 5 mg/L. Embryonic development of the snails in egg masses was monitored using photomicrographs from which embryonic diameters were estimated. Such measurements revealed that ovicidal effects were developmentally stage specific and normally induced a curtailment of development during the gastrula to trochophore transition.