Grass Hosts of Pyrenophora tritici-repentis. J. M. Krupinsky, Research Plant Pathologist, Agricultural Research Service, U.S. Department of Agriculture, Northern Great Plains Research Laboratory, P.O. Box 459, Mandan, ND 58554-0459. . Plant Dis. 76:92-95. Accepted for publication 2 August 1991. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source, The American Phytopathological Society, 1992. DOI: 10.1094/PD-76-0092.

Sixty-two isolates of Pyrenophora tritici-repentis were obtained from diseased leaves collected from 25 grass species. Nine species were previously unreported hosts, including Agropyron fragile subsp. sibiricum (Siberian wheatgrass), Andropogon gerardii var. paucipilus (sand bluestem), Bromus biebersteinii (meadow brome), Festuca ovina (sheep fescue), Koeleria pyramidata (June grass), Schizachyrium scoparium (little bluestem), Setaria viridis (green foxtail), Stipa comata (needle-and-thread), and Thinopyrum ponticum (tall wheatgrass). All isolates from grass hosts produced symptoms on detached seedling leaves of wheat (Triticum aestivum) and were considered pathogenic. Significant isolate effects in all analyses were interpreted to indicate that isolates from the grass hosts differed in their ability to cause disease symptoms on wheat. A number of isolates from grass hosts were as aggressive as a wheat isolate. Cultivar effects were significant in 86% of the analyses, indicating that differences in symptom response among wheat cultivars were detected when tested with isolates from the grass hosts. However, the cultivar × isolate interaction was nonsignificant in 86% of the analyses, indicating a lack of specific interaction between isolates and cultivars.

Keyword(s): Drechslera tritici-repentis, tan spot, yellow leaf spot.