Impact of six essential oils on strawberry gray mold

Gray mold caused by Botrytis cinerea is the most important disease after strawberry fruit harvest. The use of chemical fungicides can have a negative effect on the health of consumers, so the use of plant essential oils for disease management has been considered. The effect of six plant essential oils on the pathogen and the contamination of strawberry fruits was investigated in this research to identify suitable essential oil to control the disease.

The pathogen was isolated from infected strawberry fruits in northeastern Iran. The inhibitory effect of different concentrations of peppermint, savory, caraway, cumin, eucalyptus and thyme essential oils on mycelial growth and germination of the pathogen spores was tested by mixing them with culture medium. Then, the effect of these essential oils in liquid and vapor phases on the contamination of strawberry fruits was tested. After normalization, the data of these experiments were analyzed by analysis of variance with MSTAT-C software and the means were compared with Duncan test.

Essential oils of caraway and eucalyptus had the greatest effect in inhibiting the growth of pathogen mycelium. Essential oils of caraway, cumin, savory, thyme and peppermint had the greatest effect in inhibiting the germination of pathogen spores. The essential oils of caraway, cumin, savory, thyme and peppermint in the vapor phase, the essential oils of caraway and eucalyptus in the liquid phase, prevented further contamination of the fruit.

The findings of this study show that all of these plant essential oils can significantly prevent the growth of mycelium and germination of pathogen spores and contamination of strawberry fruits, but the effect of caraway essential oil in most cases is better than others. Thus, it can be used as an alternative to fungicides on strawberry fruit.