Leaf Scald on Plum Shoots Growing from Disease-free Buds. A. J. Latham, Associate Professor, Department of Botany, Plant Pathology and Microbiology, Auburn University, Auburn, AL 36849. J. D. Norton, Professor, Department of Horticulture; and M. W. Folsom, Graduate Research Assistant, Department of Botany, Plant Pathology and Microbiology, Auburn University, Auburn, AL 36849. Plant Dis. 64:995-996. Copyright 1980 American Phytopathological Society. DOI: 10.1094/PD-64-995.

Buds free of leaf scald symptoms were grafted on plum trees infected with rickettsialike organisms. Typical scald symptoms developed on plum shoots from surviving buds. Rickettsialike organisms with characteristic rippled cell walls were seen by electron microscopy in xylem extracts and xylem cross sections of petioles from leaf scald-affected leaves. Crushing petioles in 0.1 M KOH and examining the extract under a phase contrast microscope was an effective method for evaluating leaves when a vacuum extraction method could not be used.