Antifungal effects of extracts from Origanum compactum Benth and Eucalyptus grandis on gray mold from Strawberry

Botrytis cinerea, responsible for gray mold, is a highly destructive disease of strawberries in Morocco. Fungicides are commonly used to control this pathogen, but they present considerable dangers to the environment and human health. Thus, it is necessary to look for new efficient non-polluting alternatives such as medicinal plant extracts. The goal of this research was to evaluate the antifungal potency of aqueous extracts and essential oil (EO) of Origanum compactum Benth and Eucalyptus grandis against B. cinerea in vitro. The chemical composition of EO was also examined through gas chromatography-mass spectrometry (GC-MS). Different concentrations of extracts were tested on the Malt medium inoculated with the pathogen. The findings revealed that the Minimum Inhibitory Concentrations (MICs) of aqueous extracts of all medicinal plants are the same for mycelial growth and sporulation of B. cinerea. MICs of EO from O. compactum Benth are 0.5 μL/mL against B. cinerea, while the MICs of EO of E. grandis are 0.6 μL/mL. The different compounds of EOs were identified. Thymol and carvacrol are the major chemical compounds of O. compactum Benth, while Eucalyptol and Gamma-Terpinene are the major compounds for E. grandis. Extracts of two medicinal plants induced a total irreversible inhibition on the mycelial growth of B. cinerea.