Toxigenic Alternaria species from Argentinean blueberries

► The genus Alternaria was the main component of the blueberry mycobiota. ► A. tenuissima species-group was the most frequently isolated. ► Tenuazonic acid, alternariol and alternariol methylether were investigated. ► Toxicogenic potential of Alternaria from blueberries was demonstrated. ► Pathogenicity toward blueberries ranged from moderate to very pathogenic.