Abstract

Studies were carried out to determine the efficacy of three spices (Allium sativum L., Capsicum frutescens L., and Zingiber officinale Rosc.) against S. zeamais reared on sorghum grains. Doses of 0.5, 1.0 and 1.5 g of each of A. sativum, C. frutescens and Z. officinale and 0.12 g of permethrin were applied to 20 g of sorghum grains infested with S. zeamais under constant conditions of 30 ± 2°C and 65 ± 5% R.H. In all the treatments, 100% mortality among adult of S. zeamais reared on sorghu treated with all the powders was obtained. The effect of the spices on adult mortality was significant (p<0.05) between the powdered spices and the control. The effect of the different spices applied at varying amounts on grain damage caused by S. zeamais was significantly (p<0.05) different with the highest (33.30%) in petri dishes with 1.5 g of C. frutescens and the least (3.30%) from treatments of 0.5, 1.0 and 1.5 g of Z. officinale and C. frutescens, respectively. The findings of this study indicated that the selected spices showed their potentiality in reducing sorghum grain damage caused by S. zeamais.

Key words:  Allium sativum, Capsicum frutescens, Protectants, Sitophilus zeamais, Sorghum grain, Zingiber officinale.