Disease Note.

Puccinia coronata on Barley. Y. Jin, Department of Plant Pathology, North Dakota State University, Fargo 58105. B. J. Steffenson, L. E. Oberthur, and P. S. Baenziger. Department of Plant Pathology, North Dakota State University, Fargo 58105; and Department of Agronomy, University of Nebraska, Lincoln 68583. Plant Dis. 76:1283. Accepted for publication 31 August 1992. Copyright 1992 The American Phytopathological Society. DOI: 10.1094/PD-76-1283C.

In 1991, winter barley (Hordeum vulgare L.) planted in a nursery near Clay Center, Nebraska, was heavily infected by a rust pathogen. Disease severity ranged from 21 to 90% in plots and averaged 46% in the nursery. The rust also was found on spring barley, foxtail barley (H. jubatum L.), quackgrass (Elytrigia repens (L.) Nevski), and common buckthorn (Rhamnus cathartica L.) in the Red River Valley region of North Dakota, South Dakota, and Minnesota in 1992. Most of 30 barley genotypes tested for disease reaction to a single-pustule isolate of the rust fungus in the greenhouse were susceptible at all growth stages up to maturity. Infection occurred on leaves, leaf sheaths, awns, and peduncles. In addition to being highly virulent on cultivated and wild species of Hordeum, this rust pathogen is virulent on Secale and many gramineous species. On barley, newly formed uredinia were elongate and light orange, and the teliospore apical cell had four to six appendages up to 46 µm long. U redial characteristics, teliospore morphology, and host range indicated that the rust was a putative variety of Puccinia coronata Corda and differed from P. coronata var. avenae W.P. Fraser & Ledingham (cause of crown rust of oat) by having low pathogenicity on Avena spp., darker urediniospores, and longer telial appendages. Because of high virulence on barley and a wide host range, this rust could become a problem in barley production.