Pseudobulbs on Cattleya turning brown

[Mathias]

I need help! A very prescious Cattleya is affected by some discease that is turning front pseudobulbs brown. It is not affecting the roots.

The symptom started after a repot, probably by some damaged roots. I cut of the pseudobulb and kept the plant dry until ut stopped. However, when I resumé watering it started on the next pseudobulb again.

The pseudobulb is not especially soft or mushy. Just brown. I noticed small blisters. It starts at the rhizome and moves slowly up the bulb.

And help is appreciated!! Here are some pics from the last pseudobulb I cut.

 

[Stone]

I think it might be too late to save it. Once the rot gets into the rhizome it is almost impossible to stop if there are no unaffected bulbs well away from the infection which you can isolate. You can try to remove the the last good bulb, hope the infection has not reached it (unlikely) soak it in a systemic fungicide and plant it in a small pot of sphagnum moss. Also, if it is bacterial, fungicides wont help.
Good luck.

 

[gonewild]

Looks like maybe Phytophthora (fungus). Basically to save it do as Stone said.
I would separate the one green stem and after treatment treat it like a backbulb and leave it unplanted and dry until a new root emerged.
Take care Phytophthora is spread by water.