The Efficacy of Three Botanical Leaf Powders (Ocimum gratissimum, Azadirachta indica, and Carica papaya) in the Control of Rice Weevil (Sitophilus oryzae)

Abstract

Rice is an economically important crop and the most important staple food for the world’s population. The aim of the study was to evaluate the efficacy of three botanical leaf powders, scent leaf, neem and paw-paw in the control of rice weevil Sitophilus oryzae on stored rice grain. The leaf powders were mixed with the rice grain at the quantities of 3g, 6g, 9g and 12g per 20g of rice. In the control, no treatment was used. The plant leaves were dried under room temperature and ground into fine powders. The experimental design adopted for the experiment was Complete Randomized Design (CRD) and each treatment was replicated four times for each experiment. Ten (10) adult S. oryzae unsexed were introduced into each vial including the control and were subsequently covered with muslin cloth held tightly in place by a rubber band to avoid their escaping. The experiments were monitored for 96 hours. The results showed that all the plant leaf powders were good grain protectants. Scent leaf recorded its highest percentage mortality of 40% in 6g, 9g, and 12g after 48 hours, whereas neem had its highest percentage mortality of 40% in 6g and 12g at 48 hours, while paw-paw recorded its highest mortality of 40% in 9g and 12g at 48 hours. No mortality was recorded in the control experiment. These botanical leaves powders especially scent leaf should be incorporated into grain protection practice of resource poor farmers and small scale rice dealers.