Antifungal activity of Asteriscus graveolens (Forssk.) Less essential oil against Fusarium oxysporum f. sp. albedinis, the causal agent of “Bayoud” disease on date palm

Abstract

Date palm (Phoenix dactylifera L.) is an important food source and commercial perennial crop in the Sahara and North Africa. “Bayoud”, a vascular wilt disease, incited by the soilborne fungal pathogen Fusarium oxysporum f. sp. albedinis (FOA), has become a serious threat to date production in date palm-growing regions in Morocco. Substantial body of research reported antifungal properties of a wide range of plant extracts. The present work aims to determine chemical composition and anti-FOA activity of Asteriscus graveolens (Forssk.) Less (AG) essential oil. GC/GC-MS analysis revealed the presence of forty-two distinct chemical components in the essential oil samples. The main compounds of the studied essential oils were 6-Oxocyclonerolidol (7.7–73.8%), cis-8-acetoxychrysanthenylacetate (0.6–50.1%) cis-chrysantenyl acetate (0.3–15.4%), 6-hydroxycyclonerolidol (2–13.3%), τ-cadinol (0.4–12.2%) and α-oxobisabolene (0.2–5.5%). Mycelial growth and spore germination of FOA were found to be strongly inhibited by the oil when tested using agar dilution assay. The lowest essential oil (EO) concentration that inhibits 100% of mycelial growth was 3500 ppm for leaves and 4000 ppm for aerial parts EO. These findings contribute significant insight into the potential of using plant extracts for controlling “Bayoud” disease.