Effect of Pre-Treatment with Plant Powders on the Nutrient Composition of Maize Grain Zea Mays Infested by Weevil Sitophilus zeamais Motsch

Abstract

Quality deterioration in maize grain as judged by changes in proximate composition caused by S. zeamais after three months post infestation was determined by proximate analyses of the maize grain before and after the infestation. Fifty grammes of maize were treated with 0.5 g and 1.0 g of each plant powder (i.e. kernel of Azadiracta indica, bulb of Allium sativa, rhizome of Zingiber officinale, leaves of Nicotiana tabacum and Ocimum basilicum and along with conventional insecticide, Coopex). The results showed that the percentage total protein determined by the estimate of total nitrogen content did not decrease much after three months of post infestation. The percentage ash in the maize grain decreased with storage period. The percentage fibre was higher in the untreated control (7.02%), than on the treated grains (3.23%). The percentage carbohydrate however, decreased (69.85%) with increase in infestation period. The minerals content in infested grains decreased substantially due to insect feeding. The findings have indicated that all the tested materials have potentials of reducing effect of S. zeamais on the nutritional composition of maize grains at 1.0g of powder/50g of grains, but A. indica is more efficacious.