Larvicidal Potentials of Three Indigenous Plants Against Malaria Vector, Anopheles Gambiae L.

Malaria is one of the highest causes of mortality in the populations of African, South Asia, and Latin America as it contributes a large part of the continued impoverishment of these populations. The efficacy of both the ethanolic and aqueous extracts of the fruits of Calotropis gigantea, R. Br. (Ascelepiadaceae), Aframomum melegueta K. Schum (Zingiberaceae), and seeds of Blighia sapida (Sapindaceae) were tested on the third instar larvae of Anopheles gambiae (L). 200 g of the blended form of each plant material was suspended in 500 mls of water and filtered after 1 day. The filtrates were then dried to get the stock from which serial concentrations (20, 10, 1, 0.1 mg/ml) were reconstituted. The result after a 24 hrs bioassay time shows that the A. meleguta (59.4 %) ethanolic extract with LC50 values of 0.3 mg/ml acted most followed by its aqueous form (38.89 %) with LC50 2.57 mg/ml, ethanolic extract of C. gigantea (27.78 %) with LC50 5.57 mg/ml, the ethanolic form of B. sapida (27.5 %) 6.25 mg/ml while the aqueous forms of C. gigantea and B. sapida were 6.37 at 25 % and 6.5mg/ml at 26.6% respectively. For all the plants used, A. melegueta was the most potent plant and there was significant difference (p<0.05) between the ethanolic extract and the aqueous form. The use of insecticides of plant origins may serve as a suitable alternative to chemical insecticides in the future with their characteristic relative safety, degradability, and abundance in many areas of the world. [ABSTRACT FROM AUTHOR]