Effects of Pruning on Tomato Plants Supporting Epiphytic Populations of Clavibacter michiganensis subsp. michiganensis . W. M. CARLTON, Former Graduate Student, Department of Plant Pathology, Iowa State University, Ames 50011. M. L. GLEASON, Extension Plant Pathologist, and E. J. BRAUN, Associate Professor, Department of Plant Pathology, Iowa State University, Ames 50011. Plant Dis. 78:742-745,. Accepted for publication 28 April 1994. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/PD-78-0742.

Infection of pruning wounds by epiphytic populations of the bacterial canker pathogen, Clavi-bacler michiganensis subsp. michiganensis, increased the amount of diseased foliage and vascular colonization in field-grown tomato plants in 1991 but not in 1990. Pruning significantly reduced yield from inoculated plants compared with nonpruned inoculated plants in 1991 but not in 1990. Inoculation significantly reduced estimated yield in both years. Pruning had no effect on disease development or yield in noninoculated tomato plants.