Control of the Cowpea Beetle Callosobruchus Maculatus (F.) (Coleoptera: Bruchidae) on Stored Cowpea Using Vegetable Oils

Abstract

Coconut oil and two types of palm oil (Palmin oil and Frytol oil) were evaluated for the control of the cowpea beetle, Callosobruchus maculatus (F.) on stored cowpea. The oils were applied at the rate of 4, 6 and 10 ml per kg cowpea. Oil treatment reduced oviposition and progeny emergence but did not affect the longevity of the adult insects. The highest dosage of 10 ml per kg seed protected the seeds for five months. Palmin oil appeared superior to coconut and frytol oil. The oils had no adverse effect on seed viability, cooking time and taste of the cooked beans after six months storage. Mould growth was, however, detected in infested oil-treated seeds stored in cotton sacks. Nutritional analysis showed that the oils did not affect the nutritional content of the oil-treated seeds and the oils did not also go rancid after the 6 months storage.