Chemical components of essential oils as a base to control two grape pathogens: Sphaceloma ampelinum and Pseudocercopora vitis

Anthracnose and grapevine leaf spot are the most important fungal diseases of fox grape in Brazil caused by Sphaceloma ampelinum and Pseudocercospora vitis, respectively. Severe attacks of either diseases can affect the yield in the current and subsequent years. Synthetic fungicides are recommended to control these pathogens in the field but may be harmful to the environment and human health over time and select for fungicide-resistant pathogen populations. Among the new strategies for safe food production, free of pesticide residues, essential oils represent a promising tool to control plant pathogens. The objectives of this study were to evaluate the antifungal activity of the volatile compounds of 26 essential oils on germination of P. vitis and S. ampelinum and of their principal active compounds as bases for development of new technological products. The essential oils of Cinnamomum zeylanicum and Cymbopogon citratus were fungitoxic to P. vitis and S. ampelinum, in vapour and liquid phases, completely inhibiting spore germination. The main compounds found in the essential oils studied were citral, geraniol, eugenol and isoeugenol. All of these, in vapour and liquid phases, were toxic to P. vitis, completely inhibiting spore germination. Citral, in the vapour phase, and citral, eugenol and isoeugenol in the liquid phase, were toxic to S. ampelinum, completely inhibiting spore germination.