Evaluation of Agropyron intermedium for Reactions to Various Leaf Spot Diseases. J. M. Krupinsky, Plant Pathologist, Agricultural Research Service, U.S. Department of Agriculture, Northern Great Plains Research Center, Mandan, ND 58554-0459. J. D. Berdahl, Research Geneticist, Agricultural Research Service, U.S. Department of Agriculture, Northern Great Plains Research Center, Mandan, ND 58554-0459. Plant Dis. 68:1089-1091. Accepted for publication 11 June 1984. 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-68-1089.

Twelve cultivars or strains of intermediate wheatgrass (Agropyron intermedium) were evaluated for reactions to leaf spot diseases under field conditions at Mandan, ND. The cultivars or strains were Greenleaf, Mandan 759, Slate, Trigo, PI 345526, Nebraska 314054, Swift Current I3702, Swift Current I3713, South Dakota 50, South Dakota 2-15, South Dakota 4-14, and South Dakota 10-14. A total of 4,800 spaced plants were established in 1980 and evaluated for 3 yr. Disease reactions differed significantly among years and among cultivars or strains. South Dakota 2-15 was rated the most resistant and Trigo the least resistant for all 3 yr. Neither heading date nor plant height were associated with resistance or susceptibility. Cochliobolus sativus was considered the most important leaf-spotting pathogen because it was isolated from nearly all plots evaluated and was present on 41% of the plated leaves. Pyrenophora trichostoma, Leptosphaeria nodorum, and a Leptosphaeria sp. were also widely distributed in the plots.

Keyword(s): hay crop, pasture.