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

Abstract

A novel species of Curvularia was identified as a foliar pathogen of Cynodon dactylon (bermudagrass) 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), glyceralde-hyde-3-phosphate dehydrogenase (GPD1) and translation elongation factor 1-α (TEF 1). 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 warm-season turfgrasses is described and illustrated as a new species, Curvularia malina.

• bermudagrass
• golf course turfgrass
• leaf spot
• multilocus phylogeny
• zoysiagrass

Acknowledgments

Much gratitude and appreciation to Robert Pratt, Clarissa Balbalian, and Amy Rossman for their critical reviews of the manuscript. This publication is a contribution of the Mississippi Agricultural and Forestry Experiment Station and golf course superintendents in South Texas Golf Course Superintendents Association of America, including Eric Bauer, Billy Weeks, and Cody Alexander. We thank Anthony Carmerino for collecting turf samples and monitoring disease outbreaks in Harris County, Texas. This manuscript was approved for publication as Journal Article No. J12001 of the Mississippi Agricultural and Forestry Experiment Station, Mississippi State University.