CHAPTER 29: Detection of Clavibacter michiganensis subsp. sepedonicus in Potato Tubers

Bacterial ring rot, caused by Clavibacter michiganensis subsp. sepedonicus, is one of the most destructive bacterial diseases of potato. It is a fastidious, slow-growing bacterium not easily isolated from potato, which is its only known natural host. The pathogen overwinters in potato tubers in storage as well as in volunteer plants and infected plant residues in the field. The pathogen grows as a biofilm in plant tissue; the bacterial cells are embedded in a polymeric matrix and become remarkably resistant to environmental challenges. Such biofilm material, dried onto potato equipment and walls of storage containers and transport vehicles, serves as an important long-term inoculum source. Disease symptoms, management methods, and protocols for pathogen detection are included in this chapter.