Association of Fastidious, Xylem-Inhabiting Bacteria with Leaf Scorch in Red Maple. J. L. Sherald, Center for Urban Ecology, National Capital Region, National Park Service, 1100 Ohio Dr., S. W., Washington, DC 20242. J. M. Wells, S. S. Hurtt, and S. J. Kostka. USDA-ARS, P.O. Box 231, Cook College, Rutgers University, New Brunswick, NJ 08903; USDA-ARS, Florist and Nursery Crops Laboratory, Beltsville, MD 20705; and Crop Genetics International, 7170 Standard Drive, Hanover, MD 21076. Plant Dis. 71:930-933. Accepted for publication 20 February 1987. 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, 1987. DOI: 10.1094/PD-71-0930.

Trees of red maple (Acer rubrum L.) were examined that showed a late-summer, marginal leaf scorch characteristic of diseases caused by fastidious, xylem-inhabiting bacteria (FXIB). Bacteria morphologically identical to the Pierce's disease bacterium and to other FXIB were found in the tracheary elements of scorch-affected leaves but not in leaves of an adjacent symptomless tree. Isolations were made from scorch-affected trees by incubating wood chips in an amended formulation of the periwinkle wilt broth medium used previously for isolating the sycamore and mulberry leaf scorch FXIB. A strain from maple cultured for serological and biochemical tests reacted positively in indirect ELISA with monoclonal antibodies specific to the FXIB, and the cellular fatty acid composition was characteristic of that of the FXIB.