Green Nanoparticle-Based Biopesticides for Sustainable Management of Citrus Canker Disease

Abstract

Citrus canker, caused by the Gram-negative bacterium Xanthomonas citri subsp. citri (Xcc), remains a major threat to global citrus production, inducing severe yield losses (up to 50%) and trade restrictions due to its aggressive virulence, environmental resilience, and rapid resistance development to copper-based fungicides. Traditional control strategies copper sprays, windbreaks, and eradication face limitations in sustainability, phytotoxicity, and regulatory scrutiny. This review explores green nanoparticle-based biopesticides as eco-friendly alternatives, synthesized via biogenic routes using plant extracts (Azadirachta indica, Aloe vera), microorganisms (bacteria, fungi, algae), and biopolymers to produce metal/metal oxide NPs (Ag, CuO, ZnO, Fe₃O₄) with enhanced antimicrobial efficacy. Mechanisms include ROS generation, membrane disruption, efflux pump inhibition, and biofilm prevention, achieving 70–100% in vitro inhibition and 50–80% field symptom reduction at low doses (10–100 ppm). Field trials demonstrate superior performance over conventional treatments, with reduced environmental persistence and minimal phytotoxicity. Challenges such as scalability, regulatory approval, and long-term ecosystem impacts are addressed, emphasizing the potential of green NPs for integrated pest management (IPM) in sustainable citrus cultivation amid climate change.