158 South Asian J Exp Biol; 1 (3): 158‐162; 2011 ISSN: 2230‐9799 Vol. 1, Issue 3, Page 158‐162 http://www.sajeb.org REGULAR ARTICLE Evaluation of leaf and vine powders of Secamone afzelii (Schult) K. Schum for control of Callosobruchus maculatus (Fab.) (Coleoptera: Bruchidae) in stored cowpea Vigna unguiculata (L.) Walp. J. M. Adesina 1 * and T. I. Ofuya 2 1 Agricultural Technology Department, Rufus Giwa Polytechnic, P. M. B 1019, Owo, Ondo state, Nigeria 2 Crop, Soil and Pest Management Department, Federal University of Technology, P. M. B. 704, Akure, Ondo State, Nigeria ARTICLE INFO Article History: Received: 20‐02‐2011 Revised: 18‐03‐2011 Accepted: 19‐03‐2011 *Corresponding Author: Telephone: +2348037110905 Email: moboladesina@yahoo.com Keywords: Callosobruchus macula‐ tus, efficacy, leaf and vine powders, reduction, Secamone afzelii, signifi‐ cantly ABSTRACT The experiment was carried out to evaluate the efficacy of Secamone afzelii leaf and vine powders applied at the rate of 0.5g, 1.0g, 1.5g and 2.0g under ambient laboratory conditions on Callosobruchus maculatus on stored cow‐ pea. Mortality of adult insects at 48 h post treatment, number of eggs laid, adult emergence, adult exit holes and percentage weight loss in each treat‐ ment were compared with those of control. The results indicated that vine powder caused significantly greater kill (P < 0.05) of C. maculatus adults when applied at 2.0g than other dosages. The application rate of 2.0g of leaf powder was able to cause reduction in number of eggs laid by the weevil (5.67/20g seed) and significantly (P < 0.05) suppressed adult emergence (21.12). Adult exit holes and percentage weight loss were significantly re‐ duced at all levels of application. It is concluded that Secamone afzelii has great potential for use as a plant‐based biopesticide for controlling C. macu‐ latus on stored cowpea. 1. Introduction Cowpea seeds Vigna unguiculata (L.) Walp are very important in meeting the dietary requirements of increasing human population in the tropics, being the affordable source of protein (Shaaya et al, 1997) and the major constraint in the storage of cowpea seeds in the tropics are infestation and damage by Callosobruchus maculatus (Ofuya and Arogundade, 2007). During storage, the weevils cause deterioration in the quality and quantity of the grains; about 30 – 50% annual loss was re‐ ported for tropical Africa (Lale, 1995; 2001). The huge post harvest losses and quality deterioration caused by these weevils is a major obstacle to achieving food security in the developing countries (IITA, 1995). The use of synthetic insecticides is the most effec‐ tive method of controlling storage pests in devel‐ oping countries (Porca et al., 2003; Ngamo, 2004). The use of these insecticides has been character‐ ised by several shortcomings such as hazard to man, livestock and the environment as result of residual effect and persistence (Ofuya, 2003; Lee et al., 2004), product adulteration (Oparaeke and Bunmi, 2006), erratic supplies and unavailability at critical period (Arannilewa, 2007). Moreover, insec‐ ticides often put a burden on the budget of small scale farmers (Mba and Okoronkwo, 2008). This