Ajayi, Folorunso A.Olomisakin, A.Anda, D.A.Ewete, O.Ogundiran, E.O.2023-12-112023-12-112011-10-09F. A. Ajayi1*, A. Olonisakin2, D. A. Anda3,0. Ewete1 and E. O. Ogundiran1 Nasarawa State University, Keffi, Faculty of Agriculture, Shabu-Lafia Campus, Department of Agronomy, P.M.B. 135, Lafia, Nasarawa State, Nigeria 2Adekunle Ajasin University, Department of Chemistry and Industrial Chemistry, Akungba-Akoko, Ondo State, Nigeria 'College of Agriculture, P. M. B. 033, Lafia, Nasarawa State Corresponding author e-mail: faajayidr@yahoo.com Received: June 05,2011; Accepted: October 09,2011https://keffi.nsuk.edu.ng/handle/20.500.14448/2997Three edible plant product oils, West African Black Pepper (WABP) Piper guineense Schum and Thonn; Claot, '<Syzgium aromaticum (L) Merril and Percy; Ethiopian pepper oil, Xylopia aethiopica (Dum) A. Rich, were studied far their effectiveness in suppressing or deterring oviposition, egg mortality and progeny emergence against the j cowpea bruchid, Callosobruchus maculatus (F) in the laboratory under ambient temperature and relative humidity. The experiment was carriedoutas treatment before infestation (TBI) and treatment after infestation (TAI) on cowpea seeds infested with cowpea bruchids. The edible plant product oil (EPPO) was used at the rate of 0.25,0.5,0.75 and 1.00 mg/lOg of cowpea seeds against cowpea bruchid C. maculatus. The TBIexperiment showed that the entire plant product oil significantly (P<0.05) reduced oviposition by C. maculatus when compared with oviposition in the control treai nents. Clave and WABP oil at the highest dosage rate of 1.00 mg completely deterred oviposition by the adult C meculatus and hence no adults emerged in the treatments. WABP oil completely deterred F, adult emergence a' the dosage rates of 0,5 and 0.75; and dove oil deterred adult emergence of the F2generation at the dosage rate of 0,75 -<ig. Ethiopian pepper oil was generally found to be less effective than clove and WABP when applied as treatment before infestation. In the TAI the three essential oils significantly (P<0.05) reduced the percentage o/C maculatus a'tults that emerged. Egg mortalities were highest in all the treatments when compared with the control and were statistically significant. No adult emerged in cowpea seeds treated with WABP andEthiopianpepperoilsat the rate of 1.00 mg/lQg seeds. The potential effectiveness of all the three edible plant product oil implied that stored cowpea seed- could be adequately protected against Callosobruchus maculatus; thus reducing their infestation and damage on &wpea seeds.___________enCallosobruchus maculatus, Cowpea, edible plant product oils, treatmentArticle