Bioprospecting of some indigenous plant bio-active materials for sustainable management of stored maize weevil Sitophilus zeamais Mostch. (Coleoptera: Curculionidae)

Stored maize (Zea mays) is jeopardized by maize weevil Sitophilus zeamais, resulting to recorded losses between 20% - 90%. Botanicals have emerged as promising alternatives to synthetic pesticides for the control of maize weevil due to their bio-insecticidal properties and minimal to zero impact on humans and the environment. In line with this, this research was conducted to evaluate the insecticidal properties of some botanicals (Tithonia diversifolia, Senna alata, Chromolaena odorataand Eucalyptus grandis) leaf powders on maize weevil. Uninfested maize grains where obtain from a local market in Buea, Southwest region of Cameroon and plant powders were obtained from ground leaves of these botanicals. In 2023, a laboratory study was conducted using completely randomized design with three replicates to evaluate the insecticidal activity of these botanicals with untreated control. All botanicals significantly reduced the number of F1 emerging when compared to the control. The number of F1 was 5, 5, 7, 7 and 15 for T. diversifolia, C. odorata, E. grandis, S. alata and control, respectively. Hatching reduction (%) followed a similar trend with 66.67%, 64.44%, 55.56% and 53.33% reported from C. odorata, T. diversifolia, E. grandis and S.alata, respectively. Cumulative mortality of maize weevil was 30.0%, 28.33%, 25.0% from C. odorata, T. diversifolia, and E. grandis respectively, which were statistically higher than S. alata (1.67%) and the control (1.67%). These plant species represent eco-friendly and sustainable alternatives for maize weevil management especially for resource-constraint farmers in developing countries in line with Sustainable Development Goals.