VIEW ARTICLE

Soil Conditions and Distribution of Pathogens in Relation to Pea Root Rot in Wisconsin Soils. D. W. Burke, Research Plant Pathologist, Crops Research Division, ARS, USDA, Prosser, Washington 99350 (formerly Visiting Professor, Department of Plant Pathology, University of Wisconsin); D. J. Hagedorn(2), and J. E. Mitchell(3). (2)(3)Professors, Department of Plant Pathology, University of Wisconsin, Madison 53706. Phytopathology 60:403-406. Accepted for publication 24 September 1969. DOI: 10.1094/Phyto-60-403.

Aphanomyces euteiches was prevalent throughout the plowed layer in 9 of 12 pea “root rot” fields and in 2 of 12 “nonroot rot” fields in southern Wisconsin. Fusarium solani f. sp. pisi was prevalent throughout the plowed layer in all 24 fields, averaging 275 to 6,175 propagules/g of soil, with no definite relationship between population and disease history. In contrast, populations of both pathogens were generally sparse immediately below the plowed layer. Neither disease histories nor pathogen numbers were correlated with recent cropping histories or with wide variations in soil pH. However, four fields in which peas had been grown repeatedly without a root rot problem, including two with a high incidence of both pathogens, had softer, less dense soil throughout the profile than the root rot fields. Soils in all fields were less compact in plowed layers than in subsoils.