In vitro control of post-harvest fruit rot fungi by some plant essential oil components.

Eight substances that are main components of the essential oils from three Mediterranean aromatic plants (Verbena officinalis, Thymus vulgaris and Origanum vulgare), previously found active against some phytopathogenic Fungi and Stramenopila, have been tested in vitro against five etiological agents of post-harvest fruit decay, Botrytis cinerea, Penicillium italicum, P. expansum, Phytophthora citrophthora and Rhizopus stolonifer. The tested compounds were ß-fellandrene, ß-pinene, camphene, carvacrol, citral, o-cymene, γ-terpinene and thymol. Citral exhibited a fungicidal action against P. citrophthora; carvacrol and thymol showed a fungistatic activity against P. citrophthora and R. stolonifer. Citral and carvacrol at 250 ppm, and thymol at 150 and 250 ppm stopped the growth of B. cinerea. Moreover, thymol showed fungistatic and fungicidal action against P. italicum. Finally, the mycelium growth of P. expansum was inhibited in the presence of 250 ppm of thymol and carvacrol. These results represent an important step toward the goal to use some essential oils or their components as natural preservatives for fruits and foodstuffs, due to their safety for consumer healthy and positive effect on shelf life extension of agricultural fresh products.

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.