Armeria maritima (Mill.) Willd. Flower Hydromethanolic Extract for Cucurbitaceae Fungal Diseases Control.

The cliff rose ( Armeria maritima ), like other halophytes, has a phenolics-based antioxidant system that allows it to grow in saline habitats. Provided that antioxidant properties are usually accompanied by antimicrobial activity, in this study we investigated the phytochemicals present in a hydromethanolic extract of A. maritima flowers and explored its antifungal potential. The main phytocompounds, identified by gas chromatography-mass spectrometry, were: hexadecanoic acid, octadecanoic acid, 9-octadecenoic acid, 3-(3,4-dihydroxy-phenyl)-acrylic acid ethyl ester, and benzeneacetaldehyde. The antifungal activity of the extract and its main constituents-alone and in combination with chitosan oligomers-was tested against six pathogenic taxa associated with soil-borne diseases of plant hosts in the family Cucurbitaceae: Fusarium equiseti , F. oxysporum f. sp. niveum , Macrophomina phaseolina , Neocosmospora falciformis , N. keratoplastica , and Sclerotinia sclerotiorum . In in vitro tests, EC 90 effective concentrations in the 166-865 μg·mL -1 range were obtained for the chitosan oligomers- A. maritima extract conjugate complexes, lower than those obtained for fosetyl-Al and azoxystrobin synthetic fungicides tested for comparison purposes, and even outperforming mancozeb against F. equiseti . In ex situ tests against S. sclerotiorum conducted on artificially inoculated cucumber slices, full protection was achieved at a dose of 250 μg·mL -1 . Thus, the reported results support the valorization of A. maritima as a source of biorationals for Cucurbitaceae pathogens protection, suitable for both organic and conventional agriculture.