Brassolaeliocattley Black Rot Fungus?

I read Diana's reply, I looked at your picture. I agree that it is a goner. So much so that I wouldn't try any remedy at all. It looks to me that the base of each pseudobulb is dead and the new growth that started has died also. There is nothing left that can grow on. This type of problem starts in the rhizome. It can spread the entire length of the rhizome, dooming the plant, before it starts to travel up the base of the pseudobulbs where it can be seen. I have a plant do this once in a while. I discovered two plants heading down this path in the last 3 months. Both had several growths (unlike your plant with only 3) and I was able to find a section where the rot had not spread yet. One looks like it will make it for sure. The other one I can't tell yet. The rhizome of your plant seems to be covered by the medium. I plant mine a little deep sometimes too because my humidity runs kind of low and I've had roots dry up before they reach the medium. I do believe planting deep makes this disease much more likely. Even more so if your humidity is also high keeping the top layers moist longer. Didn't mean to write a book.

Steve