- classification : Bacteria, Actinobacteria, Actinomycetales, Micrococcinae, Microbacteriaceae
- synonyme : Corynebacterium michiganense subsp. michiganense (Smith 1910) Jensen 1934
- English name: bacterial canker


Clavibacter michiganensis subsp. michiganensis , mainly affecting a few nightshades, was first described in North America in 1909. It is the cause of a vascular bacteriosis particularly feared by producers in many production areas on all continents . Easily transmitted by seeds and plants, it is rampant both in the open field and under shelter. In the latter, the many manipulations of plants contribute to its extension and to the increase of its incidence. It is found in both soil and soil crops, where it is present in the substrate and the nutrient solution. Its damage can be considerable: in a poorly controlled situation, almost all plants can be affected. Ultimately, the number of dead plants is high and yields are greatly reduced.

In France , as in many countries, this bacteriosis is probably one of the most feared tomato diseases , especially under shelters. In addition to the damage it causes, it often forces a reorganization of work in the crops. Once installed in a farm, it is difficult to get rid of it without the implementation of heavy measures.

The aggressiveness and host specificity of this Gram + bacterium seems to fluctuate depending on the strain studied.