EFFICACY OF Acalypha fruticosa (Eurphorbiaceae) EXTRACTS AS MOSQUITO OVICIDAL, LARVICIDAL AND PUPICIDAL AGENTS AGAINST THREE VECTOR MOSQUITOS Aedes aegypti L., Culex quinquefasciatus Say. AND Anopheles stephensi Liston. (DIPTERA: CULICIDAE)

The aerial parts of Acalypha fruticosa (Euphorbiaceae) were successively extracted with hexane, chloroform and methanol. The three extracts were studied for their mosquito ovicidal, larvicidal and pupicidal activities against the three mosquito vectors Aedes aegypti, Culex quinquefasciatus and Anopheles stephensi for 24 hours. The activities were studied for concentration levels 500, 250, 125 and 62.5 ppm for all the extracts. The percentage mortality values obtained for each concentration were subjected to probit analysis and LC50 and LC90 values were calculated. It was observed that hexane and chloroform extracts showed more activity than the methanol extract at 500ppm in all the three assays. The ovicidal efficacy of A. fruticosa was highest in hexane extract against An. stephensi and Ae. aegypti with 91% and 86% respectively at 500 ppm. In contrast, the chloroform extract showed highest ovicidal activity of 78% at 500 ppm against Culex eggs and relatively lesser activities were observed against Anopheles and Aedes. The methanol extract showed very low activity against the eggs of all the three mosquito species. The hexane extract showed the highest larvicidal activity against Ae. aegypti and An. stephensi with the LC50 values of 188.43 ppm and 170.77 ppm respectively. However the chloroform extract showed highest activity against Cx. quinquefasciatus larvae with the LC50 value of 189.22 ppm. The pupicidal activity also showed the same trend at 500 ppm. The hexane extract showed highest activity against An. stephensi and Ae. aegypti with LC50 values of 61.38ppm and 184.67 ppm respectively. The Chloroform extract was more active against Cx. quinquefasciatus, LC50 value being 224.07ppm. The findings reveal that both hexane as well as chloroform extracts of the aerial parts of the plant Acalypha fruticosa seem to possess active molecules against the three major mosquito larvae Ae. aegypti, An. stephensi, and Cx. quinquefasciatus. This is the first report of the mosquito ovicidal, larvicidal and pupicidal activities of Acalypha fruticosa hexane and chloroform extracts against Ae. aegypti and An. stephensi.