Scanning Electron Microscopy Reveals Structural Damage by Cu-based Nanoformulations in Rhizoctonia solani, Fusarium verticillioides, and Sclerotium rolfsii

Copper nanoparticles are increasingly being explored as a sustainable alternative to conventional fungicides for controlling plant pathogens, offering enhanced efficacy and reduced environmental toxicity. This study investigated the antifungal mechanism of essential oil-grafted copper nanoparticles (EGCuNPs) using scanning electron microscopy against Sclerotium rolfsii, Fusarium verticillioides, and Rhizoctonia solani. Morphological and molecular characterization confirmed the identity of the pathogens, with ITS sequencing validating the identity of R. solani (GenBank accession OR251925). In vitro assays at ED50 concentrations of EGCuNPs revealed significant growth inhibition of all three fungi. Scanning electron microscopy (SEM) demonstrated disruption of hyphae and spores, confirming the potential antifungal activity of EGCuNPs. While S. rolfsii exhibited some tolerance, EGCuNPs caused significant damage to hyphae. The study demonstrates the antifungal mechanism of EGCuNPs, proving its potential as a next-generation fungicide. Further research should address molecular mechanisms through transcriptomics and long-term ecological impacts of repeated application of copper-based nano-formulations.