Investigation on the Antifungal Potential of Thymol and Carvacrol Bearing Plants in Controlling Botrytis cinerea, the Causal Agent of Grape Gray Rot

During the last several decades the efficacy of plant extracts and essential oils in controlling plant diseases specially those of leaf spots and fruit rots have raised the interest of many researchers worldwide. Several findings have approved the antifungal potential of plant products containing Thymol and Carvacrol compounds against a wide range of plant fungal diseases including grape gray rot. Botrytis cinerea, the causal agent of grape gray rot has a wide host range and can cause severe loss in the field and during storage. In this study the antifungal efficacy of five essential oils, ie: Wild marjoram, Savory, Fennel, Wormwood and Rosemary were evaluated at three concentrations 200, 400 and 600 ppm on mycelia growth, spore germination and germ tube elongation of B. cinerea under laboratory conditions. Results indicate that Wild marjoram, Savory and Fennel at 200, 400 and 600 ppm could completely (100%) inhibit the mycelia growth as well as spore germination of this fungus respectively, while Wormwood and Rosemary had either very little or no effect on this fungus . Results also approve that Wild marjoram and Savory essential oils which contain Thymol and Carvacrol compounds, specially the first one containing both the compounds showed the highest antifungal activity against B. cinerea.