Effectiveness of Pyrethrum Dosage on Maize and Bean Weevils under Farmer's Storage Conditions in Morogoro Region, Tanzania

4.1 Abstract Storage of grains is essential in agriculture, both to initiate new life and from a food security point of view. Recently, farmers have been encouraged to use different botanical insecticides instead of synthetic insecticides because of the many problems associated with synthetic chemicals.A field study was conducted at the ten selected farmer’s stores in Morogoro, Tanzania, from November 2020 to May 2021 to evaluate the effect of pyrethrum dosage on maize and bean weevils under farmers' storage conditions. Pyrethrum powder at six dosage levels (5, 10, 15, 20, 25, and 30 g/kg) was mixed with 1 kg of disinfested maize and bean grains in separate polythene bags, and the effects on insect mortality, grain damage, and weight loss were assessed. The results showed that there was significant difference only in the highest concentration (20 g/kg and 25 g/kg for bean and maize grains respectively) pyrethrumand the control (P<0.05).Grain weight loss in pyrethrum powder-treated grains was dose-dependent, ranging from 0% in the highest dose to 26.49 and 46.52 % in beans and maize grains, respectively, in the control, with significant differences.Generally, the powders are cheap and safer for human consumption hence is recommended to be usedas maize and bean protectants in storage. Further studies on the packaging and sales of these plant powders for easy accessibility to farmers and consumers of maize is also suggested. Keywords: Maize grains; bean grains; chemical control; pyrethrum powder; maize weevils; bean weevil