Repellent Efficacy of Eight Medicinal Plants Against Sitophilus zeamais (Coleoptera: Curculionidae): Green Integrated Pest Management for Stored Grains

The objective of this investigation was to assess the efficacy of eight distinct plant materials in repelling the maize weevil, Sitophilus zeamais , a pest that is notorious for causing significant damage to stored maize. Heeng ( Ferula asafoetida ), Turmeric ( Curcuma longa ), harmal ( Peganum harmala ), neem ( Azadirachta indica ), basil ( Ocimum basilicum ), mint ( Mentha arvensis ), and tumma ( Citulluscolocynthis ), Lemon grass ( Cymbopogon flexuosus ) were the materials that were tested. The maize variety Azam was employed to test each plant material in three forms (powders, aqueous extracts and oils) and three concentrations (5%, 10%, and 15%). The experiment comprised nine treatments, one of which was an untreated control for the purpose of comparison. The maize weevil was significantly repelled by all plant material formulations and concentrations, as evidenced by the results. In comparison to aqueous extracts and granules, the oil consistently demonstrated the highest repellency among the various formulations. Both A. indica and C. Colocynthis was found to be particularly effective and can be used as essential oils or extracts to repel this pest. The research also demonstrated that repellency was enhanced by higher concentrations of plant materials, while it was diminished by extended exposure times. Neem exhibited the highest repellency, with a range of 91.81% to 98.25%, followed by harmal (87.80–95.62%) and turmeric (72.22–86.71%) at a 15% concentration after 24 hours of treatment. In contrast, the repellency of heeng, lemongrass, and mint was the lowest, with heeng ranging from 51.65–71.08%, lemongrass from 39.74–65.31%, and mint from 25.76 to 49.01% after 24 hours of application.