Bioefficacy of Leaves Extracts of Five Selected Plants against Larvae of Malaria Mosquito Species Anopheles gambae and Culex quenquifasciatus and Formulation of Larvicide

Résumé

Plants are rich sources of alternative agents for the control mosquito because they possess bioactive chemicals which act against mosquito species including specific target insects and are eco-friendly. The need for a more effective larvicide with broad host specificity leads to this study which evaluated the larvicidal efficacy of aqueous and ethanolic leaf extracts from Jatropha curcas, Azadirachta indica, Senna tora, Ficus thonningii and Delonix regia against the larvae of Anopheles gambiae and Culex quenquifasciatus. Larvicidal bioassay showed concentration dependent activity of both ethanolic extracts of Ficus thoningii and Delonix regia were indicated a positive correlation of LC₅₀ and LC₉₀ at 0.021, 0.004 and 1.312, 0.226 respectively against Anopheles gambiae, while Azadirachta indica, Senna tora and Ficus thoningii indicated a positive correlation of LC₅₀ and LC₉₀ at 0.032, 0.376, 0.231 and 0.467 5.433, 3.337 respectively against Culex quenquifasciatus. The LC₅₀ and LC₉₀ values of aqueous extracts were determined based on the transformed PROBIT analysis and were observed to be 0.017, 0.058, 0.035 and 0.206, 0.716, 0.438 for Jatropha curcas, Azadirachta indica and Delonix regia respectively, indicated a positive correlation against Anopheles gambiae, while  Jatropha curcas, Azadirachta indica, Senna tora and Ficus thoningii also indicated a positive correlation of LC₅₀  and LC₉₀ at 0.008, 0.029, 0.100, 0.018 and 0.069, 0.260, 0.883, 0.159 respectively against larvae of Culex quenquifasciatus. The aqueous extracts were found to be more potent than the ethanolic extract. Jatropha curcas, and Azadirachta indica were more effective against the larvae of malaria mosquito Anopheles gambiae and Culex quenquifasciatus.