The protective effect of selected plant powders against the rice weevil, Sitophilus oryzae (Coleoptera: Curculionidae) in wheat grains in comparison with a model insecticide: in vivo and in Silico analysis

Abstract Background The rice weevil acts as one of the primary harmful pests of stored cereals, posing a substantial threat to rice and other stored grains. It is difficult to identify and control due to its internal infestation behavior, quick reproduction, and resistance to traditional pesticides. Treatments using natural compounds are environmentally safe. They provide an affordable substitute. Methods The insecticidal properties of five plant powders, black pepper, clove, neem, garlic, and bay-laurel, were tested against the rice weevil ( Sitophilus oryzae ). In silico approaches were employed to predict the eco-friendly insecticidal potential and simulate the pharmacokinetic properties of compounds identified through GC-MS analysis. The physicochemical properties of Malathion as a model insecticide and high-percentage phytocompounds were evaluated, and their potential toxicity profiles were determined. The adult mortality, progeny reduction, wheat grain weight loss over seven weeks, and repellency were evaluated and compared to treatment with Malathion. Results Neem exhibited the highest mortality rate (87.5%), followed by clove, bay laurel, garlic, and black pepper (48.75%). Neem and clove demonstrated the highest progeny reduction (88.07%, 84.41%) and weight loss reduction (2.98%, 9.73%), respectively. The LC50 values decreased over time, suggesting an increase in toxicity with prolonged exposure. Clove exhibited the highest repellency (64.17%), followed by neem (59.17%) and garlic (51.67%). The phytochemical makeup of oils derived from the selected plants was analyzed using gas chromatography- mass spectrometry. In silico analysis for selected major plant components was performed, and the mechanism of toxicity was determined compared to Malathion. Eugenol, a significant component in clove, showed superior physicochemical compatibility as a drug-like molecule in comparison to 9,12-Octadecenoic acid, the primary component in neem. Conclusion Neem and clove powders showed promising insecticidal and grain-protecting potential as eco-friendly alternatives to chemical insecticides, emphasizing their sustainable potential for post-harvest grain protection. Graphical abstract