Determination of In-Vitro Antifungal Activities of Essential Oils Against Fungal Pathogens

Abstract

This study was carried out to determine the in-vitro antifungal activities of essential oils obtained from thyme (Thymus vulgaris), Turkish pickling herb (Echinophora tenuifolia subsp. sibthorpiana), clove (Syzygium aromaticum), cinnamon (Cinnamomum zeylanicum), eucalyptus (Eucalyptus globulus), dill (Anethum graveolens), juniper (Juniperus communis), and ginger (Zingiber officinale) against Rhizoctonia solani and Fusarium solani infections. Essential oils were added to autoclaved potato dextrose agar (PDA) medium at 0, 500, 1000 and 2000 ppm doses. Mycelium disks of both fungi with a diameter of 5 mm were transferred to the center of petri dishes and incubated at 24±2 °C for 7 days. By measuring the mycelial development diameters of fungi, the biocontrol efficiencies of essential oils were calculated. Essential oil applications showed significant antifungal activity against R. solani infection and cinnamon, thyme and clove essential oils at 1000 ppm, and dill essential oil at 2000 ppm doses completely inhibited mycelial development. The biocontrol efficiencies of juniper (%2.4-12.6), eucalyptus (%2.8-26.6) and ginger (%18.2-37.3) essential oils against R. solani were found to be low. While clove and thyme essential oils completely inhibited F. solani mycelial development at 2000 ppm dose, the biocontrol efficiencies of ginger (%1.6-3.7), eucalyptus (%1.2-7.4) and dill (%2.9-9.8) essential oils were found to be low. It was concluded that especially clove, thyme, cinnamon and Turkish pickling herb essential oils showed high in-vitro antifungal activity against both phytopathogens and may have the potential to be used as an alternative to synthetic fungicide active substances.