Biocontrol of Maize Weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), in Maize over a Six-Month Storage Period.

Abstract

Food security is contingent upon increasing crop yields but also upon reducing crop losses to post-harvest pests and diseases. Weevils are particularly important agents of post-harvest losses in grain crops. A long-term evaluation of a biocontrol agent, Beauveria bassiana Strain MS-8, at a single dose of 2 × 109 conidia kg-1 of grain was formulated in kaolin as a carrier at levels of 1, 2, 3, and 4 g kg-1 of grain and screened against the maize weevil, Sitophilus zeamais. After six months, the application of B. bassiana Strain MS-8 at all levels of kaolin significantly reduced the maize weevil populations compared to the untreated control (UTC). The best control of maize weevil was observed in the first 4 months after application. Strain MS-8 applied in a kaolin level of 1 g kg-1 performed the best, resulting in the lowest number of live weevils (36 insects/500 g of maize grain), the lowest level of grain damage (14.0%), and the least weight loss (7.0%). In the UTC the number of live insects was 340 insects/500 g of maize grain, the level of grain damage was 68.0%, and weight loss was 51.0%.