Tea tree oil controls brown rot in peaches by damaging the cell membrane of Monilinia fructicola

Abstract This study tested the efficacy of plant essential oils (EOs) for controlling rot in post-harvest peaches. Three fungal pathogens from naturally infected peaches were isolated and identified, and their pathogenicity was confirmed on peach fruit. Monilinia fructicola was the most pathogenic of the three isolates (M. fructicola, Penicillium expansum and P. spinulosum). The antifungal effects of four EOs (tea tree oil (TTO), thyme oil, rosemary oil, and lemon oil) were then evaluated against M. fructicola. TTO had the strongest antifungal activity against M. fructicola in vitro and in inoculated peach fruit. Experiments designed to probe the antifungal mechanisms of TTO revealed that the EO affects the composition of the M. fructicola cell membrane, leading to changes in mycelial morphology, membrane permeability, and levels of intracellular reactive oxygen species. Based on these results, we conclude that TTO is effective against infection by M. fructicola in post-harvest peaches. TTO should be considered as a viable substitute for conventional fungicides that are currently used to control rot in peach.