Antifungal Studies of Selected Essential Oils and a Commercial Formulation against Botrytis Cinerea

Growing concerns about food safety and environmental protection have created a need for new and safe plant disease control strategies. The aim of this study was to find an alternative to synthetic fungicides currently used in the control of the devastating fungal pathogen Botrytis cinerea Pers., the causal agent of grey mould disease of strawberry (Fragariaananassa Duch). The antifungal activity of the essential oils of Origanumvulgare L., Monardadidyma L. and of a commercial formulation of thyme oil (Gloves Off®) was investigated against B. cinerea and compared with controls. Contact phase effects of different concentrations of the essential oils and commercial formulation were found to inhibit the growth of B. cinerea in a dose dependent manner. Complete growth inhibition of the pathogen was recorded at 200 µg/ml of ‘Gloves Off®’. The mycelial growth of the pathogen was significantly reduced at the highest concentration of the essential oils of O. vulgare and M. didyma tested, which was 51.2 µg/ml. Spore germination and germ tube elongation were also inhibited by the essential oils and Gloves Off®. Light microscopic observations revealed that the essential oils caused morphological degenerations, such as cytoplasmic coagulation, hyphal shrivelling and protoplast leakage of the fungal hyphae. The essential oils of O. vulgare L. and M. didyma L. are promising, antifungal agents against B. cinereasimilar to the commercial formulation ‘Gloves Off®’.