Brassia pseudobulbs discolored and dented?
 

I have a problem with my Brassia Spider's Gold.

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There are two bulbs, and they are both turning ugly colors and developing big dents and holes.

https://farm4.staticflickr.com/3927/...39b01a4d_z.jpg

https://farm4.staticflickr.com/3939/...d7970166_z.jpg

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The opposite side of one bulb looks fine.

https://farm4.staticflickr.com/3947/...9373dcd6_z.jpg

Although the bulbs are deteriorating, the two new growths seem to be developing normally.

When squeezed or pushed, the bulbs are firm, even the brown and dented areas. No mushy spots have been found.

I first noticed this a couple of months ago when one half of the pseudobulb's leaf began to yellow. I remember thinking it was odd that only one side was yellowing and not the whole thing. Eventually, the entire leaf detached from the bulb.

I don't know what I'm dealing with, and need some help with this one!

Did you cut into the rhizome and check to see if there's a purple ring inside?

This looks like what happened to my first Oncidium Sharry Baby and it turned out to be fusarium. I tossed the plant once I discovered it.

If not... I *think* it could be normal aging, but I'm not sure. My older pbulbs that have died back on my brassia hybrids tend to turn yellow and they don't get mushy, they just slowly start to dehydrate and turn brown.

I think it is fungus rot. If you cut the bulbs with a razor blade, you'd be amazed how far the disease went inside. In my experience the best prevention is Cattleya-like light and moving air.

Yep, it is rotting.
I would cut that whole pb off right now.
That should usually take care of the problem.

Thanks for the advice!

I ripped off the worst pseudobulb, but have left the other, even though it is showing signs of rot as well.

If I cut it off too, will the new growths survive without pbulbs to support them?

When there is a rot, the earlier you cut that off, the better the chance you will save the plant.
The new growth will not like it as much, but it's better than dying from rot. It has its own roots and the recovery might take one or two seasons, but it's totally worth it. You don't want to take a chance with rot.

If you feel bad about removing the pb completely and the rot is rather small, you can use a very sharp tool like a surgical mess and just cut away big scoop of the rot and its surrounding area. I have done with this with my Tahoma Glacier with good result, but I did it when the rot was less than half an inch or even smaller, and then I scooped out a big chunk.
I would have actually preferred to cut away the entire pb, but the pb was just sprouting a new shoot, so I had no other options.