Larvicidal effect of Azadirachta indica, Moringa oleifera, and Carica papaya on the development of Anopheles gambiae (Diptera: Culicidae) larvae

Abstract

A wide range of pyrethroid and organochlorine resistance has been observed across most African countries. Therefore, using eco-friendly plant botanicals to control Anopheles larvae offers a cost-effective alternative method for larval management. This study assessed the larvicidal effect of Azadirachta indica, Moringa oleifera, and Carica papaya on the growth of Anopheles gambiae larvae (Diptera: Culicidae). Azadirachta indica, M. oleifera, and C. papaya leaves were obtained, processed and crushed into powder using a Qasa electric grinder. Anopheles larvae were collected from natural breeding sites using dippers and nets. Twenty live larvae were subjected to test cups filled with 100 ml of distilled water containing A. indica, M. oleifera, and C. papaya leaf powder at concentrations of 0.001, 0.005, and 0.01 g/ml. The larvae were exposed to these treatments for 24 and 48 hours, respectively, with four replicates for each concentration. The Anopheles larvae showed 100% mortality within 24 hours when exposed to 0.01 g/ml of C. papaya. Similarly, 0.01 g/ml of M. oleifera resulted in mortality rates of 45% at 24 hours and 100% at 48 hours. In contrast, A. indica leaf powder showed the least effectiveness, with mortality rates of 2.5% and 30% observed after 24 and 48 hours of exposure. A strong positive linear relationship was observed between the concentration of A. indica (r² = 0.83), M. oleifera (r² = 0.66), and Anopheles larvae mortality. Carica papaya exhibited superior larvicidal efficacy with higher mosquito mortality and a lower LC₅₀ value. The mortality of Anopheles larvae exposed to A. indica and M. oleifera depended on concentration and duration. A. indica, M. oleifera, and C. papaya leaf powder can minimize and compliment measures towards control and inhibit development of Anopheles larvae.