Abstract

The larvicidal effect of aqueous extracts of Hemidesmus indicus roots, Gymnema sylvestre and Eclipta prostrata leaves were tested against Culex quinquefasciatuslarvae at the concentrations of 1, 2, 3, 4 and 5% up to three days. All extracts showed larval mortality. Larval mortality was 100% with the use of 5% concentration of root extract of H. indicus, leaves extracts of G. sylvestre and E. prostrata after 2 days. Qualitative analysis of the phytochemicals of aqueous extracts revealed the presence of carbohydrates, saponins, phytosterols, phenols, flavonoids and tannins in all the plants. Quantitative analysis showed that the crude saponin was the major phytochemical constituent present in highest percentage followed by crude tannin in all three plants. It is suggested that all the three plants possess larvicidal properties that could be developed and used as natural insecticides for mosquito control.

Key words: aqueous extract, larval mortality, qualitative analysis, phytochemicals, natural insecticides