Phytochemical Analysis and Insecticidal Activity of Four Plant Extracts Against Maize Weevil and Larger Grain Borer

Plant‐based biopesticides provide a sustainable alternative to synthetic insecticides for managing postharvest losses caused by maize weevil ( Sitophilus zeamais ) and larger grain borer ( Prostephanus truncatus ). This study evaluated the phytochemical composition and insecticidal activity of methanolic extracts of Lantana camara , Citrus sinensis , Moringa oleifera , and Hyptis suaveolens against these pests under laboratory conditions. Qualitative and quantitative analyses revealed the presence of alkaloids, flavonoids, tannins, saponins, terpenoids, steroids, and cardiac glycosides. Bioassays were conducted using a completely randomized design with two concentrations (0.05 and 0.1 g/mL). Actellic Super 2% dust served as the synthetic reference insecticide, while acetone‐treated grains served as the control. All plant extracts significantly reduced oviposition, larval development, and adult emergence in both insects ( p < 0.05). The extracts also exhibited strong repellency, ranging from 66% to 96%, with Hyptis suaveolens exhibiting the highest repellent activity (96.7%). The observed bioactivity is attributed to the synergistic action of phytochemicals that disrupt insect feeding behavior, growth and development. These findings highlight the potential of these botanicals as eco‐friendly alternatives for protecting stored maize.