Control of Postharvest Fungal Rots on Grapes Using Essential Oil of Foeniculum vulgare Mill

Fungal rots, caused by Botrytis cinerea and Colletotrichum acutatum, are the main causes of postharvest decay of table grapes in Brazil. The aim of this study was to assess the chemical composition and the fungicidal effect of Foeniculum vulgare essential oil in vitro, on mycelial growth (contact and volatile phase) and conidia germination, and in vivo on postharvest grapes against both fungi. The major compounds found in F. vulgare essential oil were trans-anethole (79.14%), fenchone (11.94%) and estragole (5.76%). The mycelial growth (contact phase) and conidia germination of B. cinerea were inhibited completely at concentrations of 50 and 100 ppm (µL mL-1), respectively. For C. acutatum, mycelial growth (contact phase) and conidia germination were inhibited completely at concentrations of 100 and 200 ppm, respectively. The volatile phase had a fungistatic effect on mycelial growth of both fungi at different concentrations tested, and the pure essential oil (100%) presented fungicidal effect against B. cinerea. In vivo tests were carried out using grapes of Vitis spp. cv. “Isabella” and the concentrations of essential oil tested were efficient, reducing the incidence of disease caused by B. cinerea and C. acutatum at postharvest, both in preventive and curative treatment. The concentration 200 ppm completely inhibited the incidence of both fungi. In conclusion, F. vulgare essential oil presented fungicidal action against postharvest fungal rots on grapes.