Comparative Methodology for Assessing Natural Antifungal Metabolites Compared to Synthetic Compounds in Grapevine

Grapevine (Vitis vinifera) is one of the most economically important fruit crops worldwide, but its high susceptibility to fungal diseases threatens yield and quality. Traditionally, disease management relies heavily on synthetic fungicides. Management typically depends on synthetic fungicides, which, although effective, raise concerns about environmental contamination, pathogen resistance, and chemical residues in grapes. In this context, natural antifungal compounds from native biocontrol agents represent a promising alternative. Notably, microbial volatile organic compounds (mVOCs) have attracted interest due totheir ability to suppress phytopathogenic fungi without harmful residues. However, methodologies directly comparing the efficacy of these natural metabolites with conventional fungicides remain scarce.

This study establishes a comparative methodology to evaluate the antifungal potential of mVOCs versus synthetic fungicides. mVOCs previously identified via GC-MS include ethyl acetate, isoamyl acetate, 2-phenethyl acetate (PEA), and 2-phenethyl alcohol (PEOH). These compounds were tested using double-petri dish assays and ex vivo grape models. Antifungal activity against Botrytis cinerea was assessed through disease severity scales. Preliminary findings show that 0.5 g/L concentrations of PEA and PEOH achieved complete fungal inhibition in both assays. This work provides a structured approach to evaluating mVOCs, contributing valuable insights into integrated disease management and the advancement of eco-friendly strategies in viticulture.