Larvicidal and Pupicidal Activity of Terminalia catappa Leaf Extracts on Aedes aegypti Mosquito: A Vector Intervention

Abstract

The effect of aqueous, ethanol and acetone extracts of Terminalia catappa leaves against the larvae and pupae of Aedes aegypti mosquito was studied. Early 3 rd instar larvae of Aedes aegypti mosquitoes and pupae were exposed for up to three days, to a dilution of 2, 4, 6, 8 and 10% of aqueous extracts and 100, 200, 300, 400 and 500ppm of ethanol and acetone extract of leaves. All tested extracts showed larval mortality. Except aqueous extract, other extracts showed pupal mortality. However, larval mortality was greatest with the ethanol extract followed by acetone and aqueous extract. Maximum pupal mortality was observed in acetone extract followed by ethanolic extract. The aqueous extract did not show any pupal mortality. Based on Probit analysis, the LC50 values of aqueous, ethanol and acetone extract of Terminalia catappa for the 3 rd instar larvae was found to be 5%, 166.0ppm and 177.8 ppm and for the pupae it was 169.8 ppm and 161.4 ppm for ethanolic and acetone extract respectively. The results were statistically significant at P<0.05 level. Qualitative analysis of the extracts revealed the presence of saponins, tannins, flavonoids, alkaloids, terepenoids and phenols. The results suggest that the leaf extract of Terminalia catappa could be used as an effective herbal larvicidal and pupicidal agent against Aedes aegypti without causing damage to the environment