Evaluation of Mosquito Larvicidal Activities of Seed Coat Extract of <i>Cassia sophera</i> L.

Abstract

In the present study an attempt was made to analyze the larvicidal activity of crude and ethyl acetate extracts of matured seed coat of Cassia sophera against Culex quinquefaciatus . Crude and ethyl acetate extracts of matured seed coat of Cassia sophera was tested against Culex quinquefaciatus . The lethal concentration was determined and the appropriate lethal concentrations at 24 h for ethyl acetate extract was also studied on non target organisms such as Daphnia sp., Diplonychus annulatum (predatory water-bug) and Chironomus circumdatus larvae (insect). Phytochemical analysis of the crude extract of matured seed coat of Cassia sophera was also done. All the graded concentration (0.6%, 0.7%, 0.8%, 0.9%, 1%) showed significant (p<0.05) larval mortality and result of regression equation revealed that mortality rates were positively correlated with concentrations of extracts. LC 50 and LC 90 values were calculated at different time intervals, and the lowest values were obtained at 72 h for first instar larvae. In ethyl acetate solvent extract the mortality rate was higher at 520 ppm against Culex quinquefaciatus than the other doses. There was no mortality of non-target organism within 72 h of post exposure to LC 50 concentration at 24 h of both crude and solvent extracts under the laboratory condition. The result of preliminary qualitative phytochemical analysis of the seed coat revealed the presence of some secondary metabolite such as saponin, alkaloid and cardiac glycosides. The results support that the tested plant extract can be used for control of larval form of Culex quinquefaciatus .