Antifungal Efficacy of Green-Synthesized CuO-ZnO Nanoparticles and Biodegradable Films Embedded with CuO-ZnO Nanocomposites against Storage Phytopathogens

Storage fungi management is important for reducing postharvest losses, especially under ambient conditions favorable for the sudden proliferation of microorganisms. The antifungal activity of biosynthesized copper oxide and zinc oxide nanoparticles along with a biodegradable Chitosan, Polyvinyl Alcohol, and Hydroxyethyl Cellulose films impregnated with CuO-ZnO nanocomposites were evaluated against major storage phytopathogens such as Aspergillus sp., Alternaria sp., and Colletotrichum sp. The fungal isolates collected were purified and then multiplied under controlled laboratory conditions before being tested for their antifungal activity. The nanoparticles were tested at three concentrations-100, 150, and 200 ppm-by the disc diffusion method, while the nanocomposite films were tested at incorporation levels-0.1%, 0.3%, and 0.5%. CuO and ZnO nanoparticles showed distinct concentration-dependent inhibition; however, CuO has shown the highest antifungal activity against all tested pathogens. Aspergillus sp. responded most strongly with an inhibition of 33.00 mm from CuO and 27.00 mm from ZnO at 200 ppm, showing strong dose responsiveness. On the other hand, Alternaria sp. and Colletotrichum sp. also responded quite positively but with a species-specific pattern of sensitivity. Biodegradable nanocomposite films have shown typical antifungal potential due to the film matrix itself, which increased further when CuO-ZnO nanoparticles were incorporated into them, and the highest response was observed in Alternaria sp. at 0.3% filling. Thus, the green synthesized metal oxide nanoparticles, particularly CuO, are found to be highly effective antifungal agents and incorporation of these into biodegradable films offers an eco-friendly strategy for storage fungi control. These findings support the possibility of using nanoparticle-based formulations as environmentally friendly alternatives to synthetic fungicides in the effort to enhance postharvest protection and reduce storage-related losses.

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