A Bacterial Kernel Spot of Barley Caused by Pseudomonas syringae pv. syringae. R. A. Peters, Former Graduate Student, USDA, ARS, Plant Pathology Department, North Dakota State University, Fargo 58102. R. G. Timian, Research Plant Pathologist, USDA, ARS, Plant Pathology Department, North Dakota State University, Fargo 58102, and D. Wesenberg, Research Agronomist, USDA, ARS, Aberdeen Experiment Station, Aberdeen, ID 83210. Plant Dis. 67:435-438. Accepted for publication 22 November 1982. 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, 1983. DOI: 10.1094/PD-67-435.

Necrotic spots on developing barley kernels, observed only rarely before 1977, were common on sprinkler-irrigated barley cultivar Klages in southern Idaho in 1977. Necrotic lesions on barley leaves and leaf sheaths were observed in 1980. Affected kernels had tan to dark brown necrotic spots with distinct margins. A Gram-negative, oxidase-negative, fluorescent bacterium identified as Pseudomonas syringae pv. syringae was the causal organism. P. syringae strains isolated from blighted seed and necrotic leaves were identical in pathogenicity on several hosts and were indistinguishable in physiological tests. Infection of barley lemmas occurred most often in kernels inoculated before the lemma became attached to the seed.