www.ccsenet.org/ijb International Journal of Biology Vol. 4, No. 1; January 2012 ISSN 1916-9671 E-ISSN 1916-968X 96 Bioactivity of Anacardium occidentale (L) and Allium sativum (L) Powders and Oils Extracts against Cowpea Bruchid, Callosobruchus maculatus (Fab.) [Coleoptera: Chrysomelidae] K. D. Ileke (Corresponding author) Department of Environmental Biology and Fisheries Adekunle Ajasin University, PMB 001 Akungba Akoko, Ondo State, Nigeria Tel: 234-803-431-8706 E-mail: kayodeileke@yahoo.com O. F. Olotuah Department of Plant Science and Biotechnology Adekunle Ajasin University, PMB 001 Akungba Akoko, Ondo State, Nigeria Received: October 10, 2011 Accepted: October 25, 2011 Published: January 1, 2012 doi:10.5539/ijb.v4n1p96 URL: http://dx.doi.org/10.5539/ijb.v4n1p96 Abstract The powders and oils extracts of Anacardium occidentale (L.) seeds and Allium sativum (L.) bulbs were tested as contact insecticides against the cowpea bruchid, Callosobruchus maculatus (Fab.) in cowpea seeds. The powders were incorporated at rates 1, 2.5 and 5/20g of cowpea seeds and acetone extracts of the plants were also applied at 0.5, 1 and 1.5ml per 20g of cowpea seeds to assess contact mortality of adult insect, oviposition, adult emergence and damage assessment. The results obtained showed that at 72 hours; 1, 2.5 and 5/20g of cowpea seeds evoked 63.3, 80 and 100% adult mortality of the cowpea bruchid while the corresponding results for A. sativum were 60.7, 73.3 and 100% mortality respectively. All concentration of acetone extracts that were used evoked 100% mortality of C. maculatus after 72 hours of post treatment. Complete protection of seeds and complete inhibition of adult emergence in both powders and extracts of A. occidentale and A. sativum were achieved. The results obtained from this research revealed that powders and extracts of A. occidentale seeds and A. sativum bulbs were effective in controlling cowpea bruchid, C. maculatus in stored cowpea seeds. Keywords: Callosobruchus maculatus, Anacardium occidentale, Allium sativum, Bioactivity, Biopesticide, Cowpea seed, Weevil Perforation Index 1. Introduction Cowpea, Vigna unguiculata occupy a prominent place in the nutrition of Nigerians because their edible seeds form cheap alternative source of dietary protein (Ofuya, 2001; Ofuya and Adedire , 2004; Adedire et al., 2011). Cowpea seeds are veritable source of minerals and vitamins such as calcium, thamine and riboflavin (Nelson, 1991). Cowpea have therefore been described as “poor man’s meat”. The major problem facing grains storage in Nigeria and other Africa countries are several insect pests including weevils, beetles and moths, leading to loss in weight and seeds quality (Adedire, 2001; Udo, 2005; Akinkurolere et al., 2006; 2009; Adedire et al., 2011). Bruchid especially those belonging to the genus Callosobruchus can infest stored cowpea seeds (Ofuya and Bamigbola, 1991) and this insect pest has been recognized as a constraint to food security in African (Markham et al., 1994). Apart from contamination of food grains by dead insects, pupae and larval cocoons, their integument has been found to contain various carcinogenic compound such as ethyl, methyl and methoxy quinines which can not be denatured by boiling or baking (Zehrer, 1980; Adedire et al., 2011).