Cowpea seed bruchid, Callosobruchus maculatus (F) (Coleoptera; Crysomelidae) is a
cosmopolitan field -to- store insect pest which is ranked as the principal post-harvest pest of
cowpea in tropics and sub-tropics (Jackkai and Daouest, 1986; Singh et al., 1990). This pest
causes substantial quantitative and qualitative losses which are manifested by seed perforation
and weight loss, reduction in market value and germinability of seed (IITA, 1989, Adeduntan
and Ofuya, 1998).
According to Caswell (1980) and (Singh et al. (1983), it was revealed that, at least 4% of the
total annual production of about 30,000 tonnes valued at over 30 million US dollars is lost
annually in Nigeria alone to this bruchid infestation. Under traditional storage conditions, 100%
infestation of this cowpea occurs within 6monthsor more often, within 3 to 5 months of storage
(Booker, 1967; Caswell and Akibu, 1980; Seck, 1993). It was estimated that bruchid causes huge
damage amounted to 20% -50% on stored seeds and sometimes this damage could accounts for
100% because of its high reproductive capacity (Shaaya et al., 1997; Udo and harry, 2013;
Mogbo et al., 2014 Tufail et al., 2015).