Previous View
APSnet Home
Plant Disease Home

Disease Note.

First Report of Magnaporthe poae, Cause of Summer Patch on Annual Bluegrass, in Ohio. J. C. Stier, Department of Plant Pathology, The Ohio State University, Columbus 43210. W. W. Shane, Department of Plant Pathology, The Ohio State University, Columbus 43210. Plant Dis. 74:252. Accepted for publication 4 December 1989. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/PD-74-0252B.

Magnaporthe poae Landschoot & Jackson (2), the cause of summer pa1ch (1), was isolated from symptomatic annual bluegrass (Poa annua L.) in golf course putting green at Cincinnati and Columbus during the summer of 1988. Small (<15 cm chlorotic patches typical of the early symptoms of summer patch consisted of plants with decayed crowns and discolored roots covered with dark ectotrophic hyphae. The teleomorph, required for accurate identification, was produced in vitro (acidified potato-dextrose agar) only wben paired with the compatible mating type (2). Perithecia, asci with refractive apical rings, and ascospore morphology and measurements were similar to those reported by Landschoot and Jackson (2). Pathogenicity of Ohio isolates was verified with Koch's postulates in greenhouse studies. Kentucky bluegrass (P. pratensis L. 'S-21') and P. annua were inoculated with millet seed infested with M. poae at the time of planting in sterilized sand. This is the first published report of M. poae in Ohio.

References: (1) P. J. Landschoot and N. Jackson. Phytopathology 77:119, 1987. (2) P. J. Lnndschoot and N. Jackson. Mycol. Res. 93:59, 1989.