Effect of Blending Amaranth Grain with Maize Kernels on Maize Weevil Control during Storage

Abstract

HighlightsMixing amaranth grain and maize is a promising pesticide-free method for controlling maize weevils in stored maize.A 1:1 mixture by volume of maize and amaranth reduced the number of live weevils by 66% after 160 d of storage as compared to maize stored without amaranth.A further reduction in live weevils could be achieved by completely covering all maize kernels with a layer of amaranth.Insect-infested maize-amaranth mixtures had reduced spoilage due to mold during storage as compared to insect-infested maize stored without amaranth.Abstract. Amaranth (Amaranthus spp.) is used as a vegetable, food, forage, and sometimes an ornamental. Amaranth grain has higher protein content than other cereals, making it a good choice for human consumption. Maize is among the three most widely grown grains in the world, but it can experience large postharvest losses during storage due to infestation by the maize weevil (Sitophilus zeamais). Due to the small size of amaranth seeds, this study postulated that amaranth grain can be blended with maize during storage to fill the intergranular spaces between maize kernels, reducing the overall void volume to minimize maize weevil movements to access the kernels, and thereby controlling the maize weevil population. The objective of this study was to investigate the effects on maize weevil control of blending maize with amaranth grain during storage versus storing maize alone. Three 208 L (55 gal) steel barrels were loaded with 160 kg (353 lb) of maize, and three were loaded with a maize-amaranth mixture (1:1 by volume), all with initial weevil populations of 25 live weevils per kg of maize. Blending maize with amaranth for storage reduced the number of live weevils after 160 days by 66% compared to storing maize alone. Additional reduction of live weevils could be accomplished if the maize were completely covered by amaranth grain, further restricting maize weevil access to the maize kernels. Keywords: Broken corn and foreign material, Insects, Insect infestation, Mechanical damage, Moisture content, Postharvest losses, Relative humidity, Temperature, Test weight.