Productivity of Tribolium Species (Coleoptera; Tenebrionidae) within Flours Derived from Edible Tubers and Effects on Proximate Composition

Abstract

The productivity of Tribolium species within flours derived from edible tubers and effects on proximate composition were assessed. Population of adults T. castaneum were obtained from infested product of flour commodities by grain merchants at Samaru Zaria Market. The experiment was carried out in the Laboratory in a Completely Randomized Design (CRD) with triplicates. Four edible tubers yam (Dioscorea sp.), cassava (Manihot esculenta), sweet potatoes (Ipomoea batata), and cocoyam (Colocasia esculenta) were flake and sun dried and then pulverised to powdered form, 8g of each were then measured. Proximate analysis was conducted. The level of moisture in the flours ranges from 7.10% - 12.50%, ash (0.16% - 1.27%), lipid (0.10% - 0.58%), crude protein (2.50% - 12.00%), crude fiber (0.10% - 1.10%), carbohydrate (86.05% - 96.52%). It was concluded that low amounts of ash, lipid, moisture and proteins in cocoyam flour compared to other flours can explain why T. castaneum was not able to develop and multiply faster on this flour. Cocoyam flour showed the lowest level of total weight loss, thus it is considered as the least susceptible to infestation, while sweet potatoes and yam had the highest level of total weight loss, thus they were the most susceptible. It was therefore recommended that when considering T. castaneum management on stored flours, more attention and concentration should be directed towards comparing of cereals flours with root and tubers flours in order to determine which flour has the highest vulnerability to infestation.