Dendrobium Nobile type, brown pseudobulbs.

[Russski]

Hi I have a problem with my dendrobium, for some time bseudobulbs are turn brown. It is not soft, but I don't like the color. What could be wrong?

[gnathaniel]

Hard to tell from your photo, but it could be fungal rot spreading through the rhizome, I've lost a few of this type to similar infections. If so you might be able to save part via swift 'surgery' and fungicide treatment, then laying remaining parts in damp moss, but I've had only occasional success with such methods.

On the other hand, pseudobulbs will often yellow with age and/or high light exposure, so might be entirely more benign than my above suggestion...

[NYCorchidman]

I see rot right there on the lower part of the cane on the far left.
The browning of the other cane might be from the same issues.
The fact that it's spreading from down up and that more than one cane is affected, it's not good.
You might want to take the plant out of the pot and check the base of the plant.