Relationships of Soil Temperature and Moisture to Clubroot (Plasmodiophora brassicae) Severity on Radish in Organic Soil. B. A. Thuma, Graduate Research Associate, Department of Plant Pathology, Ohio Agricultural Research and Development Center, Ohio State University, Wooster 44691. R. C. Rowe, Associate Professor, and L. V. Madden, Assistant Professor, Department of Plant Pathology, Ohio Agricultural Research and Development Center, Ohio State University, Wooster 44691. Plant Dis. 67:758-762. Accepted for publication 2 December 1982. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-758.

Effects of rainfall, soil temperature, and soil moisture on clubroot severity on radish (cultivar Scarlet Knight) were investigated in naturally infested Carlisle muck soil. Cumulative rainfall in the first 2–3 wk, soil temperature throughout the growth period, and interaction of soil temperature with soil moisture were the variables most highly correlated with disease development. Regression equations were developed to predict severity of clubroot as a function of these variables.

Keyword(s): Raphanus sativus.