Curvularia malina sp nov incites a new disease of warm-season turfgrasses in the southeastern United States

A novel species of Curvularia was identified as a foliar pathogen of Cynodon dactylon (bermuda-grass) and Zoysia matrella (zoysiagrass), two important warm-season turfgrasses in the southeastern United States. Field symptoms were conspicuous chocolate brown to black spots in turf of both species on golf course putting greens and fairways. Leaves of plants within these spots exhibited prominent, black eyespot lesions from which a darkly pigmented fungus was consistently isolated. The fungus produced gray- to black-olivaceous mycelium within 10 d on potato dextrose agar at 25 C but never produced conidia despite numerous attempts to induce them. Field symptoms were reproduced in inoculated plants of both grasses, and re-isolation of the pathogen from symptomatic tissues confirmed its pathogenicity in fulfillment of Koch's postulates. A phylogenetic analysis was performed using sequence markers of internal nuclear ribosomal transcribed spacer region (ITS), glyceraldehyde-3-phosphate dehydrogenase (GPD1) and translation elongation factor 1-alpha (TEF1). The concatenated phylogenetic tree showed strong support for a new species within Curvularia that is distinctly divergent from other Curvularia spp. Therefore, the darkly pigmented pathogen of was m-season turfgrasses is described and illustrated as a new species, Curoularia malina.