One of the most recent methods for plant diseases management is to protect the plants from pathogenic microorganism via application of essential oil based compounds. In this study, at first, some post-harvest pathogenic fungi of grape were isolated in Arak and Botrytis cinerea was identified as the dominant species. To evaluate the antifungal effect of essential oils, effect of different concentrations of essential oils of plants including: thyme oil (Zataria multiflora, 10 to 350 ppm), pennyroyal oil (Mentha pulegium, 75 to 1000 ppm), cumin oil (Cuminum cyminum, 75 to 500 ppm), on radial growth of B.cinerea. Experiments were performed using the macro dilution causal agents method and the minimum inhibitory concentration (MIC) was determined. The results showed that the thyme and cumin were able to prevent the growth of the pathogen in vitro at very low concentration (125 and 350 ppm), with 100% inhibition of radial growth of the fungus. In all essential oils, with increasing concentration, the inhibition on mycelial growth of fungi increases. The lowest MIC belonged to thyme and cumin, and mentha respectively. As a result these products can be used to make suitable formulations as natural fungicides that can be replaced with synthetic fungicides[1,2
