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Etiology

Pathogenicity of Some Ectotrophic Fungi with Phialophora Anamorphs that Infect the Roots of Turfgrasses. P. J. Landschoot, Assistant professor, Department of Agronomy, The Pennsylvania State University, University Park 16802; N. Jackson, Professor, Department of Plant Sciences, University of Rhode Island, Kingston 02881. Phytopathology 80:520-526. Accepted for publication 27 November 1989. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/Phyto-80-520.

Magnaporthe poae, Gaeumannomyces incrustans, G. cylindrosporus, and Phialophora graminicola (anamorph of G. cylindrosporus) were identified on turfgrasses in Rhode Island and New York. M. poae was isolated from Poa annua and Poa pratensis, and G. incrustans was isolated from P. pratensis exhibiting symptoms of summer patch disease. G. cylindrosporus or P. graminicola were obtained from P. pratensis and Lolium perenne exhibiting only a decline in quality. At 28 C, M. poae was highly pathogenic to 8-wk-old turf of P. pratensis and P. annua and to 7-yr-old turf of P. pratensis. G. incrustans was mildly pathogenic to P. pratensis and P. annua, whereas G. cylindrosporus or P. graminicola were parasitic but not pathogenic to the same hosts. M. poae also was pathogenic to Agrostis palustris, Festuca rubra var. commutata, Festuca arundinacea, L. perenne, Hordeum vulgare, Triticum aestivum, Avena sativa, and Secale cereale. When inoculated into mature (22-mo-old) turf of P. pratensis, M. poae produced symptoms of summer patch. M. poae was reisolated from the roots and crowns of diseased plants, confirming a causal relationship between M. poae and summer patch disease.