Efficacy of plant essential oils on postharvest control of rot caused by fungi on four cultivars of apples in vivo

The efficacy of plant essential oils was evaluated on apples, cv. Golden Delicious, cv. Granny Smith, cv. Red Chief and cv. Royal Gala, at postharvest to control Botrytis cinerea and Penicillium expansum. The essential oils from basil (Ocimum basilicum), fennel (Foeniculum sativum), lavender (Lavandula officinalis), marjoram (Origanum majorana), oregano (Origanum vulgare), peppermint (Mentha piperita), rosemary (Rosmarinus officinalis), sage (Salvia officinalis), savory (Satureja montana), thyme (Thymus vulgaris) and wild mint (Mentha arvensis) were tested at different concentrations. All the essential oils were from mediterranean plants. The fruits were artificially wounded and inoculated with a suspension at 1 x 10⁵ conidia/ml of each pathogen. After 12 h, emulsions at 1% and 10% of each essential oil were dropped into each inoculated wound. A tebuconazole chemical control and an inoculated control were also included. All the treated fruit were stored at 4 ± 1°C. After 15 and 30 days, the diameter of the rot around each wound was measured. The results revealed that the efficacies of the essential oils tested were cultivar- and storage time-dependent. In any case, treatments with essential oils from oregano, savory and thyme showed significant efficacy in all apple cultivars tested. Treatments with essential oil emulsions at 10% were phytotoxic for all the apple cultivars evaluated. Copyright © 2010 John Wiley & Sons, Ltd.