Larvicidal activity of the cold and hot water leaf extracts of <i>Azadirachta Indica</i> a. Juss (meliaceae) against the larvae of <i>Culex guinquefasciatus</i> say (diptera: culicidae)

Abstract

This study investigated the potency of the cold and hot water leaf extracts of Azadirachta indica A. Juss (Meliaceae) against the third instar larvae of Culex quinquefasciatus (Say) (Diptera: Culicidae), the vector of lymphatic filariasis. Ten actively swimming third instar larvae of Cx. quinquefasciatus were exposed to different concentrations of 0.0, 1.0, 2.0 and 3.0 % (w/v) of cold and hot water leaf extracts of A. indica, after which percentage larval mortality was monitored for 24 and 48 hours. Results from this study revealed that both extract types (cold and hot water) of A. indica demonstrated excellent larvicidal activities against the larvae of Cx. quinquefasciatus at all tested concentrations (excluding the control – 0.0 % w/v). Percentage larval mortality was slightly a function of both concentration and exposure duration. Following a 48 hour exposure period of Cx. quinquefasciatus larvae to different concentrations of A. indica cold and hot water leaf xtracts, the highest concentration (3.0 % w/v) of both extract types was observed to demonstrate a perfect larvicidal activity (100 %) against the test insect. In conclusion, this study recommends the application of A. indica cold and hot water leaf extracts in the control of Cx. quinquefasciatus specifically at their potential breeding sites and also in areas where lymphatic filariasis is endemic.

Keywords: Azadirachta indica, Leaf extracts, Larvicidal activity, Culex quinquefasciatus