THE EFFICIENCY OF FOUR SELECTED PLANT EXTRACT [OCIMUM GRATISSIMUM, AZADIRACHTA INDICA, CAPSICUM ANNUUM AND CITRUS LIMON] AGAINST CALLOSOBRUCHUS MACULATUS IN COWPEA

Callosobruchus maculatus is a species of beetles known commonly as the cowpea weevil or cowpea seed beetle. The cowpea which is infested by Callosobruchus maculatus and plant extracts ( Neem leaf, scent leaf, lemon and dry red chilli pepper) were sourced from Akungba Akoko, Ondo state, Nigeria. The plant extracts were air dried in room temperature and turned into powdering form which serves as a formulated insecticide against cowpea weevil. 3g of infested cowpea was placed into four different containers adding 1ml (high dose), 0.75ml(medium dose) and 0.5ml(low dose) of formulated insecticide in different portions with an exception of the control container. The emergence rate and mortality rate of the cowpea weevil in each of the containers were recorded and monitored for four weeks. In the control, emergence rates increased dramatically over four weeks, indicating rapid population growth of untreated weevils. In contrast, the treated groups exhibited significantly lower emergence rates, with the 0.5 ml concentration showing moderate control, the 0.75 ml concentration providing better control, and the 1 ml concentration maintaining the lowest emergence rates, demonstrating a strong dose-dependent response. There was no record for mortality rate in the control, while the highest rate of mortality was recorded in high dose due to the higher concentration of the formulated insecticide applied. Comparing the medium dose to the low dose, the medium dose was more effective due to the higher concentration of formulated insecticides than low dose