Effects of ZnO Particle Size and Shape on Antifungal Activity Against Fungi Associated with Zea mays in Guachochi, Chihuahua, México

Fungal contamination of maize can threaten crop health and food safety, motivating the search for alternatives to synthetic fungicides. Here, zinc oxide (ZnO) nanomaterials with nanorod (ZnO-R), lamellar (ZnO-L), and undefined (ZnO-N) morphologies were synthesized by modified hydrothermal and precipitation methods. The characterization confirmed a crystalline structure for all morphologies. Samples were evaluated in vitro against Fusarium spp., Alternaria spp., and Paecilomyces spp. isolated from maize tissues at concentrations of 250, 500, and 1000 ppm. Factorial analysis of day-7 radial growth showed significant effects of morphology, fungal group, and concentration (p < 0.0001), as well as significant two-way and three-way interactions (p < 0.001). The three-way interaction indicated that morphology-associated differences depended on the fungal group and concentration. The highest mean radial growth occurred for ZnO-N against Fusarium spp. at 250 ppm (4.033 mm), whereas the lowest occurred for ZnO-N against Alternaria spp. at 1000 ppm (2.267 mm). Overall, ZnO nanomaterial effects depended on the combination of morphology, fungal group, and concentration; no single morphology was uniformly superior across all tested conditions.