Antifungal activity of asparagus extracts against phytopathogenic Fusarium oxysporum

• Evaluation of antifungal effect of asparagus extract enriched in flavonoids.
• Asparagus extract inhibits growth of Fusarium oxysporum pathogenic to horticultural crops.
• Asparagus extract inhibits sporulation of F. oxysporum pathogenic to horticultural crops.
• Safety of asparagus extract enriched in flavonoids in asparagus plants growth.

Asparagus, carnation and strawberry are major horticultural crops in southern Spain, where diseases caused by soilborne pathogens are frequent. Among them, Fusarium spp. are the fungi more frequently associated to the infection of underground plant organs. Flavonoids are phenolic compounds which possess a wide range of biological activities, including antifungal activity. In this work we evaluated the in vitro effect of an extract enriched in flavonoids obtained from triguero asparagus by-products against Fusarium oxysporum pathogenic to asparagus, carnation and strawberry, as well as its safety in asparagus plants. A significant inhibition of mycelial growth and sporulation of F. oxysporum f. sp. asparagi, F. oxysporum f. sp. dianthi and F. oxysporum pathogenic to strawberry was obtained by the addition of the asparagus extract enriched in flavonoids in three independent experiments and using the amended plate technique. Besides, in vitro tests were conducted aiming at assessing the effect of the extract in asparagus plants. Seed germination and growth of asparagus in medium amended with the asparagus extract enriched in flavonoids were similar to those in the not amended medium. Our results constitute the first report of the antifungal properties of bioactive compounds, mainly flavonoids, from asparagus by-products, and show these extracts as a promising alternative within horticultural crop protection strategies.