The potency and effectiveness of six essential oils in controlling grapevine trunk diseases in Morocco

Abstract

The objective of this study was to evaluate the antifungal activity (AA) of essential oils (EOs) extracted from Eucalyptus globulus Labill. (Eucalyptus), Citrus limonum (L.) Burm. (Lemon), Cinnamomum zeylanicum Blume. (Cinnamon), Lavandula latifolia aspic (Lavender), Rosmarinus officinalis L. (Rosemary), and Mentha spicata L. (Peppermint) against four pathogenic fungi responsible for grapevine trunk diseases in Moroccan vineyards. The EOs with the highest in vitro efficacy were selected for further testing on autoclaved grape wood assays against Diplodia mutila, Neoscytalidium novaehollandiae, Trichothecium roseum, and Neopestalotiopsis vitis. The major chemical constituents of the tested EOs were determined through GasChromatography–Mass Spectrometry (GC-MS) analysis, and their relative percentages were recorded. All tested EOs demonstrated significant antifungal activity against the four pathogens, as evidenced by in vitro results. Redundancy analysis (RDA) confirmed the efficacy of the tested EOs against grapevine fungal pathogens. The efficacy of each EO varied depending on the pathogen being targeted. For example, lavender had the highest efficacy across EOs (81.37%) against T. roseum, while peppermint was the most effective in inhibiting D. mutila (47.45%). Cinnamon was the most effective EO in controlling N. vitis (73.33%), while rosemary had the best effect in controlling N. novaehollandiae (56.79%), with the most effective EC₅₀ value (8.66 µL/ml) being attributed to the rosemary EO. The in vitro results were further confirmed through autoclaved grape wood assays, with inhibition of proliferation ranging between 93.14% and 66.32%. These findings represent a novel application of EOs extracted from various medicinal plants to control fungal diseases in grapevine plantations.