ABSTRACT This study evaluated the antifungal potential of essential oils and plant extracts for the control of Monilinia fructicola , the causal agent of brown rot in peaches, under in vitro and postharvest conditions. Essential oils and cold aqueous, hot aqueous, and hydroalcoholic extracts of Allium sativum , Syzygium aromaticum , Origanum vulgare , Rosmarinus officinalis , Artemisia absinthium and Eugenia uniflora were evaluated using direct and indirect contact assays. In vitro assays showed complete inhibition of mycelial growth by the essential oils of A. sativum , S. aromaticum and O. vulgare , comparable to the chemical control (captan). The essential oil of A. sativum exhibited the lowest minimum inhibitory concentration (0.04%), whereas essential oils of S. aromaticum and O. vulgare showed minimum inhibitory concentrations of 0.16%. Plant extracts exhibited predominantly fungistatic effects. Scanning electron microscopy revealed structural damage to fungal hyphae induced by the essential oils, confirming their fungitoxic activity. In postharvest assays, only the essential oil of O. vulgare and the chemical treatment, when applied by direct contact, completely suppressed disease incidence and severity over 7 days of storage. Although the essential oils of A. sativum and S. aromaticum reduced disease development at early stages, their efficacy decreased over time, particularly under indirect contact. Biochemical analyses indicated that essential oil treatments, particularly O. vulgare , induced defence responses in the host fruit, as evidenced by increased protein content and enhanced phenylalanine ammonia‐lyase and chitinase activity. These results indicate that essential oils—particularly that of oregano—act through a dual mechanism involving direct antifungal activity and induction of fruit defence responses. These findings highlight their potential as sustainable alternatives for postharvest management of brown rot in peaches.
Baseggio et al. (Thu,) studied this question.