Evaluation of the Insecticidal Effect of Aqueous Ricinus communis Leaf Extract Against the Cigarette Beetle (Lasioderma serricorne) (Coleoptera: Ptinidae) in Wheat Grains Prior to Storage

الملخص

     This study evaluates the insecticidal potential of aqueous Ricinus communis leaf extract against Lasioderma serricorne when applied to wheat grains prior to storage. Laboratory experiments were conducted at the Chemistry Department, University of Tripoli. Five extract concentrations (5%, 20%, 50%, 70%, and 100%) were tested alongside a control, using 300 insects per treatment, distributed across three replicates. The extract was applied via light spraying, followed by proper ventilation to ensure rapid drying. After 48 hours, mortality rates ranged from 19% at 5% concentration to 96% at 100%. The LC₅₀ value, confirmed through Probit regression analysis, was 38.7%, indicating moderate toxicity. Statistical analysis using ANOVA and Tukey’s HSD test revealed significant differences among treatments. The insecticidal effect is attributed to active compounds such as myristic acid, stearic acid, flavonoids, and terpenoids, while the absence of ricin enhances the safety profile of the extract. The study recommends using concentrations between 20% and 50% as a pre-storage treatment for wheat grains, ensuring surface dryness to prevent mold development.