Septoria spraguei, Pyrenophora trichostoma, and Cochliobolus sativus Incidence on Russian Wildrye Grass Leaves and S. spraguei Host Range. J. M. Krupinsky, Plant Pathologist, Agriculture Research Service, USDA, Northern Great Plains Research Center, P.O. Box 459, Mandan, ND 58554. J. D. Berdahl, Research Geneticist, Agriculture Research Service, USDA, Northern Great Plains Research Center, P.O. Box 459, Mandan, ND 58554.. Plant Dis. 68:13-16. Accepted for publication 7 July 1983. 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, 1984. DOI: 10.1094/PD-68-13.

Of 112 samples of Russian wildrye (Elymus junceus) leaves collected in 1982 in North Dakota, 57% were infected with Septoria spraguei, 51% with Pyrenophora trichostoma, and 68% with Cochliobolus sativus. All three fungi were also isolated from other Elymus spp. S. spraguei has not been previously reported on beardless wildrye (E. triticoides), Altai wildrye (E. angustus), or European dune wildrye (E. arenarius), and P. trichostoma has not been previously reported on field collections of basin wildrye (E. cinereus), beardless wildrye, or European dune wildrye. Five isolates of S. spraguei, two from Russian wildrye and one each from basin wildrye, Siberian wildrye, and beardless wildrye, were pathogenic on a wide range of grass species and could be reisolated from each. Among 25 inoculated grass species, leaf necrosis was most severe on Russian wildrye and beardless wildrye, followed by Siberian wildrye and tetraploid crested wheatgrass (Agropyron desertorum). Lesions were fewer and smaller on spring wheat than on Russian wildrye.

Keyword(s): forage grasses.