Comparative Effectiveness of the Powders of Some Underutilized Botanicals for the Control of Sitophilus Zeamais (Motschulsky) (Coleoptera: Curculionidae)

Experiments were conducted to study the effectiveness of powders of some underutilized botanicals for the control of Sitophilus zeamais. The tested plants are: Piptadeniastrum africanum, Piper guineense, Alstonia boonei, Garcinia kola, Xylopia aethiopica, Picralima nitida and Aristolochia repens. The effects of the powders were observed at different dosage rates : 0.0g (Control), 0.5g, 1.0g, 1.5g and 2.0g per 20g of maize grains which correspond to 2.5, 5.0, 7.5 and 10.0%w/w. Twenty (20) newly emerged adults of S. zeamais were introduced into the plastic containers and percentage mortality as well as adult emergence were determined. The results showed that among the plant powders tested, Piper guineense was the most effective in all durations which gave 90% at day two (2) in the treatment with 10.0%w/w. This was followed by A. repens, root bark of P. africanum and leaf of P. africanum which gave 97.50%, 80 % and 87.5% at day four (4) in the treatment with 10.0%w/w. The effect of the plant powders of G. kola, A. boonei, X. aethiopica and P. nitida were not significantly different (p≥0.05) from the control throughout the trial period. However, there was a progressive decrease in the number of the first filial generation of S. zeamais in all the powders tested.