Vanillin enhances the antifungal effect of plant essential oils against Botrytis cinerea

Antifungal activity against Botrytis cinerea of lavender, rosemary, peppermint, sweet basil, rose, ginger, and thyme extracts alone at different concentrations (0.04, 0.19, and 0.40 mg/mL) or in combination with vanillin was investigated. Comparatively, 0.04 and 0.19 mg/mL concentrations of essential oil extracts were less inhibitory than that of 0.40 mg/mL concentrations. However, with rosemary extracts, high inhibitory activity was observed for all tested concentrations. On the other hand, the combination of essential oil extracts with vanillin exhibited a marked antifungal activity for B. cinerea with thyme, lavender, and peppermint extracts. These inhibitory effects are interesting in connection with the prevention of gray mold rot in many agricultural products and these antifungals could be used instead of synthetic products.