VIEW ARTICLE

Ecology and Epidemiology

Relation of Soil Physical and Fertility Properties to the Occurrence of Cytospora Canker in French Prune Orchards. P. F. Bertrand, Research Assistant, Department of Plant Pathology, University of California, Davis 95616, Present address of senior author: Oregon State University, Mid-Columbia Experiment Station, Rt. 5, Box 240, Hood River 97031; Harley English(2), and R. M. Carlson(3). (2)Professor, Department of Plant Pathology, University of California, Davis 95616; (3)Associate Pomologist, Department of Pomology, University of California, Davis 95616. Phytopathology 66:1321-1324. Accepted for publication 23 July 1976. Copyright © 1976 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-66-1321.

Twenty-six separate plots, located in commercial plantings of French prunes, were surveyed for soil properties and the occurrence of Cytospora canker. Trees with a high incidence of Cytospora canker were found associated with soils that were high in clay content and/or unable to supply adequate potassium. A regression equation developed from soil data and disease counts from 13 plots in a 20-year-old orchard accounted for 88% of the variation in disease occurrence. A similar equation developed from data from plots in 13 separate orchards of various ages accounted for 74% of the variation in disease occurrence.