Impacts of Lavandula angustifolia Mill. and Thymbra spicata L. essential oils on postharvest gray mold of strawberries

Antifungal activities of two essential oils (EOs), derived from the Lavandula angustifolia L. and Thymbra spicata L. plant leaves were tested in current study against two isolates (M1-5 and M3-5) of Botrytis cinerea in Potato Dextrose Agar (PDA). These studies were performed in vitro and a further in vivo test with vapor contact application of the EOs was performed with strawberry fruits to confirm the antifungal activities in postharvest storage. In vitro studies were conducted with four different application doses (0.25, 0.50, 1.00 and 2.00 mL L-1) of both EOs with poisoned food technique. The highest dose (2.00 mL L-1) of L. angustifolia had a 92.50% mycelial growth inhibition on M1-5, where the same dose of same oil had 0.00% mycelial growth inhibition on M3-5. On the other hand, the highest dose (2.00 mL L-1) of T. spicata had 16.76% and 51.18% of mycelial growth inhibition on M1-5 and M3-5, respectively. The lower doses had less or no antifungal activity, thus only the highest doses were tested in the consecutive in vivo studies. Results suggested that both of the EOs had moderate impact on the prevention of disease severity at strawberry cv. Camarosa fruits, inoculated with M1-5 and M3-5 isolates. The EOs were also noted to have a significant influence on the prevention of the weight loss and loss of soluble solids concentration. Results suggested that the vapor contact application of L. angustifolia and T. spicata essential oils have potential to be alternative to synthetic fungicides for controlling gray mold in strawberry fruits caused by B. cinerea.