Insecticidal efficiency of green-synthesized zinc oxide nanoparticles on bean weevil, Acanthoscelides obtectus Say. (Coleoptera: Chrysomelidae)

The use of zinc oxide nanoparticles (ZnO-NPs) as a bio-insecticide has gained increasing attention due to their eco-friendly properties and proven efficacy in controlling pest populations. This study comprehensively assessed the insecticidal activity of ZnO-NPs against the bean weevil, Acanthoscelides obtectus Say. (Coleoptera: Chrysomelidae) adults, by analyzing mortality rates in a dose-dependent manner under controlled laboratory conditions. ZnO-NPs were synthesized and characterized using Scanning Electron Microscopy (SEM), which confirmed their spherical shape and nanoscale dimensions (~100 nm). Adult mortality was monitored over a 10-day period at doses of 100, 250, 500, 750 and 1000 mg kg⁻¹. The two-way ANOVA results revealed that both dose and exposure duration had significant effects on insect mortality rates. Furthermore, one-way ANOVA showed a significant dose-dependent increase in mortality, with the highest dose (1000 mg kg⁻¹) achieving a corrected mortality rate of 93.3%. These findings underscore the potential of ZnO-NPs as a sustainable alternative to conventional chemical insecticides, particularly for integrated pest management strategies in stored products. Future studies should focus on optimizing control practices in storage facilities and evaluating the long-term effects on non-target organisms and explore various doses and application methods to ensure safe and effective use.