Abstract: Five Edible Plant Product Powders (EPPP), West African black pepper (Piper guineense Schum and Thonn), clove (Syzgium aromaticum (L.) Merril and Percy), Ethiopian pepper (Xylopia aethiopica (Dunn.) A. Rich), Alligator pepper (Aframomum melegueta Schum) and African locust bean (Parkia biglobosa (Jacq.) R. Br. Ex G. Donf.) were studies for their effectiveness in suppressing oviposition, egg hatch and progeny emergence against Callosobruchus maculatus (F.). Pulverized EPPP at the rate of 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 g/20 g cowpea seeds were applied as pre-treated and treatment after infestation. All the plant product powders significantly (p≤0.05) reduced oviposition by C. maculatus when tested as pre-treated application, compared with oviposition in control treatments. Consequently, F1 progeny emergence was significantly (p≤0.05) suppressed compared with emergence in control. In the treatment after infestation, egg mortalities were highest in treatments with WABP, Clove and Ethiopian pepper. There were however significant differences (p≤0.05) between the EPPP and the control treatment at all dosage rates tested. The effectiveness of the EPPP in both studies was thus ranked as follows: WABP>Clove>Ethiopian pepper>Alligator pepper>African locust bean.