Efeito de óleos essenciais sobre Lecanicillium fungicola e sua colonização em Agaricus bisporus

Abstract

In Brazil, we notice a rise in consumption and, consequently, in the production and commercialization of mushrooms, especially Agaricus bisporus, the popular champignon. This occurs because of the current major promotion of its nutritional and medicinal properties and for its price having become more accessible. However, the Lecanicillium fungicola species is considered the main pathogen for A. bisporus, growing wherever the mushroom establishes. In addition, it is known that the pathogen‟s sensibility decreases because of the fungicides currently used for its control. Therefore, this study aimed at evaluating the effect of essential oils extracted from Melissa officinalis (lemon balm), Thymus vulgaris (thyme), Origanum vulgare (oregano), Eucalyptus globulus (eucalyptus), Cinnamomum zeylanicum (cinnamon) and Syzygium aromaticum (India clove) over the in vitro mycelial growth and conidia germination of L. fungicola; as well as verifying the interaction between A. bisporus and L. fungicola by means of scanning electron microscopy (SEM). The cinnamon and India clove oils, in the concentration of 0.4%, and thyme, at 0.8%, inhibited the mycelial growth of the fungus, while oregano, lemon balm and eucalyptus oils were inefficient. The Scan Electron Microscopy revealed that, after 19 hours of L. fungicola inoculation to A. bisporus, the spores were already fully germinated, which indicates the occurrence of infection. Thus, the results of this study suggest that S. aromaticum, C. zeylanicum and T. vulgaris oils are potential alternatives in treating mushrooms for controlling L. fungicola.