Screening of twenty five plant extracts for larvicidal activity against Culex quinquefasciatus Say (Diptera: Culicidae)

Objective To determine the larvicidal activity of twenty five plant extracts against Culex quinquefasciatus ( Cx. quinquefasciatus ). Methods The larvicidal activity was determined against the third instar larvae of Cx. quinquefasciatus at 1 000 ppm concentration. Larval mortality was assessed after 24 and 48 h. Results The hexane extracts of Cleistanthus collinus ( C. collinus ) and Murraya koeingii ( M. koeingii ) plants showed 100 percent mortality at 24 h bioassay followed by diethyl ether, dichloromethane and ethyl acetate extracts of C. collinus, Leucas aspera ( L. aspera ), Hydrocotyle javanica ( H. javanica ), M. koeingii, Sphaeranthus indicus ( S. indicus ) and Zanthoxylum limonella ( Z. limonella ) after 48 h exposure. Conclusions The results indicate larvicidal activity against Cx. quinquefasciatus and further investigations are needed to elucidate this activity against a wide range of all stages of mosquito species and also the active ingredients of the extract responsible for larvicidal activity should be identified.