Larvicidal activity of some medicinal plant extracts against filariasis fever mosquito, Culex quinquefasciatus (Say.) (Diptera: Culicidae).

Objectives: The present study was aimed to find the larvicidal activity of petroleum ether, chloroform, acetone and methanolic extracts of Dichanthium foveolatum (Del.) Roberty, Leptochloa uniflora Hochst, Pancratium triflorum Roxb and Molineria trichocarpa (Wight) N.P.Balakr against Culex quinquefasciatus.

Methods: The larvicidal potential of selected plant extracts were determined against 4th instar larvae of C. quinquefasciatus with various concentrations viz., 50, 100, 150, 200 and 250 mg/ml. The mortality counts were made after 24 h of incubation and LC values were calculated.

Results: Chloroform extracts of studied plants were showed highest larvicidal activity with remarkable irritant against the larva of C. quinquefasciatus. Highest larvicidal activity was observed in the chloroform extract of D. foveolatum against the larva of C. quinquefasciatus with LC50 = 277.03 mg/ml. The larvicidal activity of the studied plants as follows chloroform extract of D. foveolatum (LC50 = 277.03 mg/ml) >L. uniflora (LC50 = 300.56 mg/ml) >M. trichocarpa (LC50 = 306.60 mg/ml) >P. triflorum (LC50 318.42 mg/ml). The larvicidal potential of P. triflorum was as follows Chloroform > acetone > methanol > petroleum ether. The larvicidal activities of L. uniflora and M. trichocarpa were as follows Chloroform > petroleum ether > acetone > methanol respectively. The larvicidal potentials of D. foveolatum was as follows Chloroform > methanol > acetone > petroleum ether.

Conclusion: The chloroform extract of D. foveolatum find use as broad-spectrum larvicidal agent in the near future. It is hoped that more work would be undertaken to evaluate the utility of these plant extracts for field applications considering the promising leads given by the present study.