Application of Some Botanicals in the Protection of Sorghum Grains Against the Maize Weevil, Sitophilus zeamais Motsch. (Coleoptera: Curculionidae)

Laboratory studies were conducted in order to assess the ability of Euphorbia balsamifera Aiton, Lawsonia inermis L., Mitracarpus hirtus (L.) DC and Senna obtusifolia (L.) Irwin and Bemeby in the protection of stored sorghum grains against damages caused by Sitophilus zeamais Motsch. Ten adult S. zeamais were introduced in 20 g of freshly harvested sorghum grains treated with 2.5, 5.0 and 10.0 × 104 ppm of powders and ethanolic extracts of the botanicals separately. The experiment was arranged in a completely randomized design (CRD) and replicated four times. The weevils were removed after 14 days leaving the grains only. All emerged adults were sieved and grain damage was assessed 84 days after treatment (DAT) while seed viability was determined after 6 months post treatment. Highest (10.00 ± 2.04 %) grain perforations (GP) was recorded in 2.5 × 104 ppm S. obtusifolia powder while 2.50 ± 1.44 % was the least GP recorded in 10.0 × 104 ppm E. balsamifera ethanolic extracts. Weight loss (WL) caused by the weevils due to their internal feeding as well as exit holes among the botanical treatments was high (4.16 ± 1.10 %) in 2.5 × 104 ppm S. obtusifolia powder, while it was low (0.89 ± 0.52 %) in 10.0 × 104 ppm E. balsamifera ethanolic extracts. Germination of treated sorghum varied between 77.50 ± 4.79 and 92.50 ± 2.50 %. The selected botanicals have shown considerable protectant ability to sorghum grains against S. zeamais infestations and could therefore be used while storing sorghum grains for seeds