Mosquitocidal efficacy of medicinal plant, Nerium oleander (Apocynaceae), leaf and flower extracts against malaria vector, Anopheles stephensi Liston (Diptera: Culicidae) larvae

Objective To assess the larvicidal efficacy of five different extracts of Nerium oleander L. ( N. oleander ) against malaria mosquitoes, Anopheles stephensi ( An. stephensi ), to combat disease. Methods The acetone, benzene, petroleum ether, chloroform, and aqueous extracts from leaves and flowers of N. oleander were subjected to distillation process in a Clevenger type glass apparatus model soxhlet. Larvicidal bioassays were performed to determine their LC 50 and LC 90 values, regression equation, and 95% confidence with lower and upper limits were calculated using probit analysis. Mortality effect was recorded after 24 h. Results The data indicated that there were significant differences in the lethality (LC 50 , LC 90 ) values of An. stephensi mosquito larvae among most of the various extracts with their controls. The order of potency with five different concentrations of flower extracts was benzene>chloroform> acetone>petroleum>water. The order of potency with similarly five different concentrations of leaf extracts was chloroform>petroleum>benzene>water>acetone. Conclusions It was concluded that there was an overall lethal effect of N. oleander extracts against mosquito, An. stephensi larvae which could be manipulated to develop a safe and effective larvicide.