Occurrence of bacterial canker in tomato fields of Karnataka and effect of biological seed treatment on disease incidence

Bacterial canker caused by Clavibacter michiganensis ssp. michiganensis was detected during a survey of tomato fields in the state of Karnataka, India. The disease incidence ranged from 25% to 48%. The pathogen was isolated from infected plant material and seeds. The pathogen was also detected in tomato seeds by laboratory assay and its identity was confirmed by biochemical, physiological, hypersensitivity in four-o'clock plant (Mirabilisjalapa) and pathogenicity tests. A seed transmission rate of up to 46% was observed in naturally infested seed. Biological seed treatment with antagonistic Pseudomonasfluorescens improved seed quality (p = 0.05) under laboratory conditions and drastically reduced the bacterial canker incidence in field. (c) 2005 Elsevier Ltd. All rights reserved.