Evaluation of insecticidal properties of an indigenous plant, Cannabis sativa Linn., against mosquito larvae under laboratory conditions

Laboratory studies were conducted with the crude ethanolic extract (CEE) of Cannabis sativa Linn., an indigenous plant, to evaluate its insecticidal properties against the larval stages of Anopheles stephensi Liston, Culex quinquefasciatus (Say) and Aedesaegypti (Linn.) mosquitoes. A concentration of 4.0 per cent induced 100.0 per cent larval mortality in all the three mosquito species in 24 h of exposure. The plant extract was found to be highly toxic to the larvae of A. stephensi followed by C. quinquefasciatus and Ae. aegypti, the LC₅₀ values being 0.10, 0.14 and 0.50 per cent of CEE, respctively. It is suggested that cheap indigenous natural insecticide would provide the alternative to overcome the various problems posed by synthetic insecticides.