In vitro evaluation of antifungal activity of Artemisia species essential oils (A. absinthium, A. dracunculus and A. vulgaris)

Due to the trend to reduce the use of synthetic pesticides and the increasing attention to environmental protection, research in the field of allelopathy, especially allelochemicals that can be used for the synthesis of biopesticides, has been intensified in recent decades. The genus Artemisia belongs to the family Asteraceae and includes a large number of aromatic and weedy species (about 500), which are known as a significant source of biologically active compounds characterized by allelopathic effects. Therefore, the aim of this study was to investigate the effect of essential oils from three species of the genus Artemisia (A. absinthium, A. dracunculus and A. vulgaris) on the mycelial growth of different isolates of the phytopathogenic fungus Colletotrichum orbiculare, the causal agent of anthracnose of Cucurbitaceae hosts in vitro. The antifungal activity of the essential oils in in vitro tests was determined using the disc volatilisation method. The essential oils were applied directly in amounts of: 1, 5, 10, 15 and 20 µl for A. dracunculus and A. vulgaris, i.e. 10, 15, 20, 25, 30 µl for A. absinthium. The concentrations of essential oils achieved in the air phase were 0.035, 0.17, 0.35, 0.53 0.70 µl ml-1 for A. dracunculus and A. vulgaris and 0.35, 0.53, 0.70, 0.88, 1.05 µl ml-1 for A. absinthium. The average IC50 values were 0.16, 0.25 and 0.62 µl ml-1 of air phase for A. vulgaris, A. dracunculus and A. absinthium, respectively. According to the IC50 values obtained, the essential oil of A. vulgaris showed the strongest antifungal potential, while the essential oil of A. absinthium showed the weakest inhibitory effect.