VIEW ARTICLE

Ecology and Epidemiology

Variation Among Strains of Clavibacter michiganense subsp. nebraskense Isolated from a Single Popcorn Field. Mary L. Smidt, Department of Plant Pathology, University of Nebraska, Lincoln 68583-0722; Anne K. Vidaver, Department of Plant Pathology, University of Nebraska, Lincoln 68583-0722. Phytopathology 77:388-392. Accepted for publication 21 August 1986. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/Phyto-77-388.

The variation among 50 single-colony strains of Clavibacter michiganense subsp. nebraskense (=Corynebacterium michiganense subsp. nebraskense) was assessed on the bases of color and morphology of colonies on solid media, bacteriocin production, pathogenicity, and bacteriophage sensitivity. All strains were isolated in 1982 from popcorn residue and popcorn plants in one 46-ha field in Nebraska. Seven major groups were identified by the first three criteria. Groupings were independent of the location within the field and the type of plant material from which they were isolated. Strains in the seven groups were further subdivided by bacteriophage sensitivity, making a total of 20 subgroups that identify a minimum of that many individual strains.