Disease Note.

First Report of Bacterial Canker of Pepper in Indiana. R. Latin, Department of Botany Purdue University, West Lafayette, Ind. 47907 . I. Tikhonova, and K. Rane. Department of Botany and Plant Pathology, Purdue University, West Lafayette, Ind. 47907. Plant Dis. 79:860. Accepted for publication 10 July 1995. Copyright 1995 The American Phytopathological Society. DOI: 10.1094/PD-79-0860E.

Clavibacter michiganensis subsp, michiganensis, the causal agent of bacterial canker, was isolated from symptomatic bell pepper (Capsicum sativum L.) from a commercial production field in northern Indiana. Affected fruit exhibited white, raised “bird’s-eye” spots that were similar to symptoms on tomato fruit with bacterial canker. There were no conspicuous symptoms on the foliage of plants with symptomatic fruit. Gram-positive bacteria with a colony morphology characteristic of C. m. subsp, michiganensis on nutrient broth-yeast extract agar were isolated from fruit lesions. The pepper strain was compared in pathogenicity tests with a strain of C. m. subsp, michiganensis that was isolated from symptomatic tomatoes from a canker-infested field. Pathogenicity tests for both strains were performed on tomato and pepper seedlings by placing a drop of bacterial suspension (approximately 108 cfu/ml) on wounds created by excising cotyledons. The procedure was repeated with a sterile water control. No symptoms were expressed on pepper seedlings inoculated with either strains. All inoculated tomato seedlings exhibited wilting and necrosis of leaf margins in 20 to 25 days. Both strains were reisolated from inoculated tomato plants. Both strains also induced hypersensitive reactions on four o’clock plants (Mirabilis jalapa) 24 h after inoculation (1). Although bacterial canker has been a common disease of processing tomatoes in Indiana for the past 10 years, this is the first time C. m. subsp, michiganensis has been associated with pepper in the state. There was no apparent yield loss attributable to the disease in the Indiana field. A nearby field of severely affected tomatoes may have served as the source of contamination. A previous report described the occurrence of bacterial canker in a commercial pepper field in California (2).