Environmentally Benign Solanum torvum (Sw.) (Solanaceae) Leaf Extract in Ecofreindly Management of Human Disease Vector, Aedes aegypti (Linn.)

Abstract

Mosquitoes play a key role in the transmission of diseases such as malaria, yellow fever, Japanese encephalitis, etc. Plant based compounds form alternate source of control measures against mosquitoes, in view of deleterious effects of chemical pesticides. In the present study, insecticidal activity of aerial part of Solanum torvum (Sw.) was studied against Aedes aegypti (L.) under laboratory conditions. GC-MS study was analysed in hexane, ethyl acetate and methanol extract of S. torvum and the leaf extracts yielded around 57 compounds. In the larvicidal and adulticidal tests against A. aegypti, mortality rate increased with the increased concentrations of S. torvum extract. Highest larval mortality was obtained with ethyl acetate 100% extract at the dose of 200 ?g/ml after 48 hrs experiment, followed by methanol 64% and hexane 42% leaf extract. The LC₅₀ values of leaf extract was observed as 159.594 ?g/mL, 182.272 ?g/mL at 24 hrs interval and 85.2833 ?g/mL, 138.472 ?g/mL 48 hrs interval for ethyl acetate and methanolic extracts, respectively. In adulticidal activity highest mortality rate was obtained in ethyl acetate extract at 92% for the dose of 2 mg/ml after 24 hrs, followed by methanol 74% and hexane 52% leaf extracts. The LC₅₀ values were 0.453 mg/mL, 0.790 mg/mL and 1.294 mg/mL with ethyl acetate, methanol and hexane extracts at 24 hrs interval against Aedes aegypti. In control treatment, no mortality rate was observed. Thus the present study showed the potential application of S. torvum leaf extract in the control of dengue mosquito under the laboratory conditions.