Characterization and use of essential oil from Thymus vulgaris against Botrytis cinerea and Rhizopus stolonifer in strawberry fruits

The essential oils from two clonal types of Thymus vulgaris (Laval-1 and Laval-2) were characterized and tested for antifungal activity. Contents were high in p-cymene, linalool, terpinen-4-ol and thymol which constituted 53.5% and 66.2% of Laval-1 and Laval-2 essential oils respectively. The essential oil volatiles from two clonal types exhibited antifungal activity against Botrytis cinerea and Rhizopus stolonifer, two common storage pathogens of strawberries (Fragaria ananassa). The inhibition of B. cinerea and R. stolonifer ranged from 26.5 to 63.5% and 5.5 to 50.5% respectively by oil from Laval-1, when exposed to concentrations of 50 to 200 ppm, while values of 36.9 to 90.5% and 11.5 to 65.8% were observed from oil from Laval-2. The decay of strawberry fruits caused by B. cinerea and R. stolonifer was controlled up to 73.6 and 73.0% respectively by volatiles from maximin concentration of Laval-1, and up to 75.8 and 74.8% from Laval-2. No visual phytotoxic symptoms were noticed for the observed period. Essential oil from Laval-2 exhibited higher antifungal activity which was related to its relatively higher content of antimicrobial compounds. (C) 1998 Elsevier Science Ltd. All rights reserved.