Activity of tea tree (Melaleuca alternifolia, Cheel) and thyme (Thymus vulgaris, Linnaeus.) essential oils against some pathogenic seed borne fungi.
Melaleuca alternifolia (tea tree) and Thymus vulgaris (thyme) essential oils were tested for their antifungal activity to investigate the possibility of their use for seed treatment. The ability of the two oils to inhibit mycelial growth was studied by in vitro assay on agar medium containing different concentrations of the essential oils (0%, 0.05%, 0.1%, 0.25%, 0.5%, 1% v/v). Seven seed-borne pathogen fungi of large interest Ascochyta rahiei, Colletotrichum lindemuthianum, Fusarium graminearum, F. culmorum, Drechslera avenae, Alternaria radicina and A. dauci were transferred on the modified medium in order to test the oils antifungal activity, by calculating the Percentage of Mycelial Growth Inhibition (%MGI) and the Minimum Inhibitory Concentration (MIC). Results showed that both the oils had a clear reducing effect on fungal growth, that was dose-dependent and it differed depending on the fungal species, confirming what is already reported in literature, with T. vulgaris oil to be one of the most potent agent against fungi. M. alternifolia and T. vulgaris oils can be considered potential alternative natural fungicides to the synthetic chemicals that are currently used to prevent and control seed-borne diseases, and could be used in agriculture for safe and eco-friendly seed-treatments.