Larvicidal and adult emergence inhibition effect of Centella asiatica Brahmi (Umbelliferae) against mosquito Culex quinquefasciatus say (Diptera : Culicidae)

Abstract

Ethanolic extract of Centella asiatica leaves were evaluated for the larvicidal and adult emergence inhibition activity against mosquito Culex quinquefasciatus under five constant temperatures 19, 22, 25, 28 and 31°C in the laboratory. Toxicity of this extract increased with temperature. The 50% medium lethal concentrations ranged between 6.84 ppm at 19°C and 1.12 ppm at 31°C. A similar trend was observed for the 90% lethal concentrations which varied from 9.12 to 3.63 ppm at the two temperatures, respectively. The adult emergence inhibition activity of this extract at LC 50 s of different temperatures was generally more pronounced in increased temperatures. These results suggest that the leaf extract of C. asiatica is promising as larvicide and adult emergence inhibitor against Culex quinquefasciatus and might be used directly in small volume aquatic habitats or breeding sites of limited size around human dwellings. African Journal of Biomedical Research Vol. 8(1) 2005: 31-33