Effects of Essential Oils on Phytopathogenic Fungi In Vitro*

The essential oils of Thymus vulgaris L., of Eavandula R.C. hybrid and Mentha piperita L. were tested in vitro against the pathogenic fungi Rhizoctonia solani Kuhn, Pythium ultimum Trow var. ultimum, Eusarium solani (Mart.) Sacc, Colletotrichum tindemuthianum (Sacc. & Magn.) Briosi & Cav. Ali the oils tested inhibited fungal growth. The most effective oil was that of thyme, with a fungicidal activity attributable to thymol, found in a concentration of 50.06% in the oil tested. SEM observations revealed that these oils cause degeneration of the fungal hyphae which appeared emptied of their cytoplasmic content