VIEW ARTICLE

Ecology and Epidemiology

Survival and Dissemination of Clavibacter michiganensis subsp. michiganensis in Tomatoes. M. L. Gleason, Department of Plant Pathology, Iowa State University, Ames 50011; E. J. Braun, W. M. Carlton, and R. H. Peterson. Department of Plant Pathology, Iowa State University, Ames 50011. Phytopathology 81:1519-1523. Accepted for publication 26 August 1991. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/Phyto-81-1519.

Rifampicin-resistant strains of Clavibacter michiganensis subsp. michiganensis, the causal agent of bacterial canker of tomato, were used to investigate the dynamics of epiphytic populations and overwintering survival of the pathogen. Epiphytic populations stabilized at 10⁶–10⁸ cfu per leaflet and 10⁵–10⁶ cfu per green fruit. After log₁₀ transformation, epiphytic populations of the pathogen on leaflets and fruit approached a normal distribution. C. m. michiganensis survived for at least 24 mo in infested debris at the soil surface, but for only 7 mo in buried debris. Infested debris that was allowed to overwinter served as primary inoculum for establishment of epiphytic populations of C. m. michiganensis on a subsequent processing-tomato crop. These plants became diseased and their yields were significantly reduced. The establishment of epiphytic populations of the pathogen and local survival can be important in the disease cycle of bacterial canker.