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Sycamore Leaf Scorch: Culture and Pathogenicity of Fastidious Xylem-Limited Bacteria from Scorch-Affected Trees. J. L. Sherald, Ecological Services Laboratory, National Capital Region, National Park Service, Washington, DC 20242. S. S. Hearon, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD 20705; S. J. Kostka, Department of Plant Pathology, University of Massachusetts, Amherst 01003; and D. L. Morgan, Texas A&M University, Research and Extension Center, Dallas 75252. Plant Dis. 67:849-852. Accepted for publication 22 January 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, 1983. DOI: 10.1094/PD-67-849.

Morphologically identical gram-negative bacteria serologically related to the Pierce's disease (PD) and elm leaf scorch bacteria were cultured from 24 of 25 scorch-affected sycamores (Platanus occidentalis) in Washington, DC, Richardson, TX, and New Orleans. LA, by incubating wood chip samples in a liquid medium similar to that used for culture of the periwinkle wilt agent. Isolates then grew readily on media developed for the PD bacterium. Roots of 19 sycamore seedlings were inoculated with one isolate from scorched sycamore. Five months after inoculation, bacteria were reisolated from 11 of the seedlings, seven of which showed leaf scorch symptoms. No bacteria were isolated from 20 control trees.