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Etiology

Etiology of Radish Scab and Its Control Through Irrigation. D. R. Levick, Former graduate research assistant, Department of Botany and Plant Pathology, Michigan State University, East Lansing 48824-1312; T. A. Evans(2), C. T. Stephens(3), and M. L. Lacy(4). (2)(3)(4)Graduate research assistant, associate professor, and professor, respectively, Department of Botany and Plant Pathology, Michigan State University, East Lansing 48824-1312. Phytopathology 75:568-572. Accepted for publication 4 December 1984. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/Phyto-75-568.

A streptomycete cultured from scabbed radishes produced typical scab lesions on radishes grown in artificially infested muck soil, and was reisolated from these lesions. On a number of growth and indicator media, this isolate differed morphologically and in growth characteristics from streptomycetes that had been isolated from scabbed potatoes. Radishes grown in a tiled, relatively dry field plot had significantly greater scab than those grown in an untiled, relatively wet plot. Radishes grown under irrigation applied at 2- to 3-day intervals were consistently less scabbed than those that had received only ambient rainfall or no rainfall. Incidence of scab was significantly lower in plots irrigated for the first 2- 3 wk after planting than in plots irrigated for only the first week.