Survival, Seed Transmission, and Epiphytic Development of Xanthomonas campestris pv. glycines in the North-Central United States. D. E. Groth, Former Research Assistant, Department of Plant Pathology, Iowa State University, Ames 50011. E. J. Braun, Associate Professor, Department of Plant Pathology, Iowa State University, Ames 50011. Plant Dis. 73:326-330. Accepted for publication 1 December 1988. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/PD-73-0326.

Xanthomonas campestris pv. glycines located in plant debris placed on the soil surface or buried at a depth of 15 cm survived through the winter in Iowa. Epiphytic populations of the pathogen developed on both resistant and susceptible seedlings that grew from seeds with either external or internal populations of X. c. pv. glycines. The pathogen dispersed from a diseased source plant in the field equally in all directions and at roughly the same rate in plots of either resistant or susceptible soybeans. The size of the epiphytic population did not differ significantly between resistant and susceptible cultivars during the first 3 wk after inoculation. However, 35 days after inoculation, external populations of X. c. pv. glycines were 20-to 50-fold greater on the susceptible plants. Eventually, disease developed on susceptible but not on resistant plants.