author(s)
Vandi Tigamba and Elias Nchiwan Nukenine

abstract
The efficacy of the pulverised seeds of Balanites aegyptiaca and Lophira lanceolata admixed with maize grains at the rates 0, 5, 10, 20 and 40 g/kg against Sitophilus zeamais was determined. The positive control, Azadirachta indica seed powder was applied at the unique rate of 5 g/kg. S. zeamais mortality was recorded 1-, 3-, 7- and 14-days post infestation, followed by the determination of F₁ progeny production and grain damage. Antifeedant activity of the powders was also assessed. At the content of 5 g/kg, powders of A. indica, B. aegyptiaca and L. lanceolata caused 70.00%, 26.25% and 25.00% mortality to S. zeamais, respectively, within 14 days of exposure. B. aegyptiaca and L. lanceolata caused maximum mortality of respectively 91.25% and 87.50% to the insect at the highest tested content of 40 g/kg, 14-days post treatment. The lowest tested content 5 g/kg of the powders from B. aegyptiaca (86.97%) and L. lanceolata (79.8%) highly suppressed progeny production, which was comparable to that of A. indica (92.20% and 86.11%, respectively), although the test powders almost completely inhibited progeny emergence, at 40 g/kg. The powders also greatly reduced grain damage and weevil feeding activity with a somewhat similar magnitude. Based on our results, seed powders of B. aegyptiaca and L. lanceolata are sufficiently potent to be considered as alternatives to synthetic insecticides for the protection of stored maize grains against S. zeamais infestation. However, safety issues need to be analysed before promoting the two botanical powders as insecticides.