Eco-Friendly Copper and Zinc Oxide Nanofertilizers for Sustainable Control of Fungal Plant Disease

This study evaluates the antifungal potential of chemical-synthesized copper (Cu) and zinc oxide (ZnO) nanoparticles against Alternaria solani and Rhizoctonia solani, compared to bulk formulations. Cu nanoparticles were synthesized using ascorbic acid and starch as eco-friendly reducing and capping agents, while ZnO nanoparticles were prepared via a precipitation method. Physicochemical characterization (SEM, EDX, FTIR, XRD) confirmed nanoscale size (1–100 nm), surface functionalization with phytochemicals, and crystalline phases (predominantly CuO for Cu; mixed Zn phases for ZnO, with possible trace Cu contamination). In vitro antifungal assays revealed that nano-formulations consistently outperformed bulk counterparts, particularly at low concentrations (50–100 mg L⁻¹) and early exposure periods (Day 2). At 300 mg L⁻¹, nano-Cu and nano-ZnO achieved 84–85% inhibition by Day 6—significantly higher than bulk treatments (72–78%). Nano-Cu also exhibited a faster inhibitory effect than nano-ZnO. These results highlight the potential of nanofertilizers as efficient, low-dose alternatives for sustainable crop protection, though synthesis purity remains critical for reliable performance.