Investigating the alleviatory ability of bio-synthesized zinc oxide nanoparticles from Sargassum ilicifolium (Turner) C. Agardh on the tomato plants exposed to whitefly infestation

Green nanoparticle synthesis presents a sustainable agricultural approach that reduces dependence on chemical pesticides while promoting environmental sustainability. The whitefly (Trialeurodes vaporariorum), a major sap-sucking pest of tomato plants, causes significant yield losses worldwide. In this study, we developed an eco-friendly management strategy using zinc oxide nanoparticles (ZnO-NPs) biosynthesized from the brown seaweed Sargassum ilicifolium, a rich source of bioactive compounds. The nanosized ZnO-NPs (5-65 nm) were applied as a foliar spray and effectively mitigated whitefly-induced oxidative stress in tomato plants. Foliar application of ZnO-NPs at 50 ppm significantly increased chlorophyll a, chlorophyll b, and carotenoid contents compared to the control. This treatment also enhanced the activities of antioxidant enzymes, including superoxide dismutase, catalase, and phenylalanine ammonia-lyase. Additionally, ZnO-NPs at 50 and 100 ppm significantly reduced malondialdehyde and hydrogen peroxide levels. ZnO-NPs exhibited strong insecticidal activity against T. vaporariorum, achieving 96.66% mortality at 1000 ppm (LC₅₀ = 407.4 ppm after 96 h). ZnO-NPs synthesized using S. ilicifolium demonstrated a dual role: priming plant defense mechanisms and acting as an effective nanopesticide. These findings highlight their potential as a sustainable strategy for integrated whitefly management in greenhouse environments. Future research should focus on field-scale validation, environmental safety assessments, and formulation optimization.