Maize is the second most widely grown cereal and gaining importance as highly nutritious crop in Ethiopia. However, evidences showed that maize is severely damaged by storage insects, mainly Sitophilus sp. and need further research to minimize losses due to this pest in storage. In line with this, research was initiated to evaluate the efficacy of three botanical plants powders against S. zeamais under laboratory conditions. Azadirachta indica L., Euphorbia trucalli and Calpurnia aurea powders were evaluated using completely randomized design (CRD) in three replications and at the rate of 1, 2 and 3g per 100g of grains and compared with untreated control. The effectiveness of the powders was evaluated on the basis of response variables like insect mortality, percentage of seed damage, weight loss, germination capacity, grain color and odor change. The obtained results showed that the powders caused 2.5 to 99% mortality at the different concentrations used with the highest concentration being most effective in killing the pests and reducing the grain damage and weight loss. Azadirachta indica and Euphorbia trucalli at 3g/100g were performed best in terms of mortality rate, reducing grain damage, weight loss and did not affect germination capacity. Moreover, there was no significant change in grain color and odor in comparison with untreated control. Based on the result, it was concluded that botanicals used in the present study have pesticidal properties to suppress S. zeamais in maize grain storage and could be used in controlling maize weevils.

Keywords: botanical plants, maize, weevil and storage