Evaluation of larvicidal efficacy of Cleome viscosa L. (Capparaceae) aerial extracts against Culex quinquefasciatus Say (Diptera: Culicidae)

To evaluate the larvicidal efficacy of crude petroleum ether, chloroform, acetone and aqueous aerial extracts of Cleome viscosa against the filarial vector, Culex quinquefasciatus. Standard World Health Organization protocols with minor modifications was adopted for the larvicidal bioassay. Larvicidal activity of exyracts was evaluated at concentrations of 62.5, 125, 250, 500 and 1 000 mg/L. Larval mortality was observed after 24 and 48 h. Amongst the solvent extracts tested, petroleum ether exhibited the highest larvicidal activity and LC50 values was 52.62 and 43.16 mg/L followed by acetone, aqueous and chloroform extract with LC50 values of 328.64 and 280.58; 493.44 and 298.76; 509.27 and 434.40 mg/L after 24 and 48 h respectively. Further investigations are needed to explore the larvicidal activity of the petroleum ether aerial extract of this plant against a wide range of mosquito species and also the active ingredient(s) of the extract responsible for larvicidal activity should be identified.