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Etiology

Etiology of Phony Peach and Plum Leaf Scald Diseases. J. M. Wells, Plant pathologist, Southeastern Fruit and Tree Nut Laboratory, Agriculture Research, Science and Education Administration, U.S. Department of Agriculture, Byron, GA 31008; B. C. Raju(2), J. M. Thompson(3), and S. K. Lowe(4). (2)(4)Plant pathologist and research associate, respectively, Department of Plant Pathology, University of California, Davis 95616; (3)Plant geneticist, Southeastern Fruit and Tree Nut Laboratory, Agriculture Research, Science and Education Administration, U.S. Department of Agriculture, Byron, GA 31008. Phytopathology 71:1156-1161. Accepted for publication 30 March 1981. 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, 1981. DOI: 10.1094/Phyto-71-1156.

Rickettsialike bacteria (RLB), previously associated with phony peach disease (PPD) and plum leaf scald (PLS), were transmitted from peach trees with PPD symptoms to plum and from plum trees with PLS symptoms to peach by grafts of root sections. Symptoms of PLS appeared on plants of plum cultivars Ozark Premier, Methley, Santa Rosa, and Shiro 9 mo after they had received root grafts from Dixiland peach with PPD symptoms. Grafted plum had RLB that appeared to be identical to those associated with PPD, measuring 0.35 × 2.0 μm, and shared similar ultrastructural details, including an outer (rippled) trilaminar membrane in the cell wall profile. Graft-transmitted RLB from plum and from peach reacted positively to immunofluorescence and enzyme-linked immunosorbent assays conducted with antiserum prepared against RLB associated with PPD.