Appropriate combinations and varied dosage of Gongronema latifolium (GL) and Diatomaceous earth (DE) powder on cowpea seed damage by Callosobruchus maculatus in storage were assessed under Entomology laboratory condition. Twenty (20 g) Kidney cowpea seeds were treated with the powders at different dosage of 0.25 g, 0.50 g and 1.00 g and binary ratios; 1:1, 1:2, 1:3, 1:4, 5:1, 4:1, 3:1, 2:1, and infested with five pairs of newly emerged C. maculatus separately into netted lid containers and left for 14 days. Each treatment, including the control comprised four replicates in a Completely Randomized Design. Results of the study shows that GLand DE powdered evoked significant (P < 0.05) mortality (30.35%) and (25.41%) after 90 days post treatment. The result also revealed that DE was more effective in achieving mortality of adult bruchids at higher dosage. Diatomaceous earth and Gongronema latifolium treated seeds had 7.33% and 10.00% exit holes; 12.08% and 12.02% seed damage; 3.00% and 2.50% weight loss in all the treatments compared with control (32.30%; 77.50%; 22.50% and 37.00%). The combination GL:DE (1:2) produced most desirable results causing lower exit hole (0.33) and seed damage (3.33%), and least seed weight loss (0.03%). Therefore, effectiveness of GL:DE (2:1), (1:3) combinations may be attributed to synergetic effects exerted on C. maculatus.
Diatomaceous earth, Gongronema latifolium, powders, mortality, combination, synergetism