An attempt of postharvest orange fruit rot control using essential oils from Mediterranean plants.

Twelve essential oils from Mediterranean aromatic plants were tested at different doses against four fungi known as causal agents of post-harvest orange fruit rot: Botrytis cinerea, Penicillium italicum, Phytophthora citrophthora, and Rhizopus stolonifer. Essential oils were obtained from Hyssopus officinalis, Lavandula angustifolia, Majorana hortensis, Melissa officinalis, Ocimum basilicum, Origanum vulgare, Salvia officinalis, and Thymus vulgaris (Family Lamiaceae), Verbena officinalis (Family Verbenaceae), and Pimpinella anisum, Foeniculum vulgare, and Carum carvi (Family Apiaceae). Because preliminary in vitro experiments showed that only the oils from V. officinalis, T. vulgaris, and O. vulgare exhibited some fungistatic activity against the above-named fungi, these three essential oils were used in successive in vivo tests carried out to protect healthy "Washington navel" orange fruits from artificial infection by the same micromycetes. The essential oil of T. vulgaris, at a 2,000 ppm dose, controlled fruit rot by B. cinerea, P. citrophthora, and R. stolonifer but was ineffective against P. italicum. Essential oils of V. officinalis and O. vulgare inhibited infection by the first two fungi and only by P. citrophthora, respectively. This finding represents an important result, with the goal of using the essential oils as natural preservatives for food products, due to their positive effect on their safety and shelf life.