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Determining the warm-season turfgrass host range of Curvularia malina sp. nov., the ink spot pathogen

Hope Renfroe: Mississippi State University

<div><em>Curvularia malina</em> is a novel pathogen causing conspicuous chocolate brown to black patches, referred to as ink spot, in bermudagrass and zoysiagrass on golf course putting greens and fairways in the southeastern United States. Black, eye-spot lesions are produced on leaves of affected plants. Three additional warm-season turfgrasses (WST) were included in a study to determine the host range of <em>C. malina</em> sp. nov. Surface-disinfested seed of centipedegrass, seashore paspalum, bermudagrass, zoysiagrass, and nodes of St. Augustinegrass were planted in <em>C. malina</em>-infested soilless mix. Thirteen inoculated and five non-inoculated replicates were included for each host. Disease severity, based on percent foliar necrosis, and shoot and root dry weights were determined 8 weeks after emergence. Zoysiagrass displayed the greatest disease severity at 54% followed by bermudagrass with 13% severity. Shoot and root dry weights of centipedegrass and seashore paspalum were reduced significantly when compared to their non-inoculated controls. Foliar lesions were observed on leaf sheaths and stolons of St. Augustinegrass; however, no differences in shoot and root dry weights were observed. <em>C. malina</em> was isolated from foliar tissue of all WST except seashore paspalum. These results indicate centipedegrass and St. Augustinegrass may serve as hosts under natural conditions and extends the host range of <em>C. malina</em>, the ink spot pathogen.</div>