12 days ago

Stem rot symptoms were seen on greenhouse-grown tomato during the 2017 winter

Affected tomato plants showed darkening of the stem and a severe stem rot symptoms. I think it's a bacterial disease... Which bacterium causes these symptoms? It is the first time that we observe this symptom. What can cause such disease?

3 answers

alex ignatov 12 days ago

I support opinion of Dr. Ravishankar Narayana, but must say that the symptoms do not look typical for Cmm. It is impossible to identify bacterial pathogen by symptoms only. It looks like the bacteria can be easy isolated in pure culture on non-selective medium.

Is there any infection on fruits? Also, is it possible to upload images of split open stem?
I think it could be a bacterial canker disease caused by Clavibacter michiganensis.

It is a seed borne disease quite common in greenhouse tomatoes. The symptoms may vary depends on age of plant, type of infection, environment and other factors. In general, the infected leaves exhibit irregular shaped water soaked lesions in between the veins, which later turn to light tan, necrotic and dark brown. Infected plants may wilt and die. Stems also shows sunken, necrotic lesions. The vascular system shows brown streaks. Yellow sticky fluid will ooze from infected stem.

http://ag.umass.edu/vegetable/fact-sh...
http://extension.msstate.edu/content/...
http://www.extension.umn.edu/garden/f...

Dr. Raffaele Giurato 12 days ago

Dear Narayana,
I think it's not C. michiganensis, because, in all cases, we have not observed the symptoms in the fruits.
This disease has affected several farms also very far apart. We had never observed such symptoms.
I think it's a bacterial disease... but to know the species only through isolation! :/

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