Help! Pseudo bulb rot on Oncidium.

I noticed a couple brown patches on one of the pseudobulbs of my new oncidium. I took a sterilized knife and dug a little bit. The rot went into the pseudobulb about 1/8" deep and 1" long. I carefully dug in, removing the rot as well as a little healthy tissue to make sure. I then dusted the wound with ground cinnamon. I'm new to orchids and think this was there when I bought it and just didn't look closely enough. I've been misting 2x daily, but going to hold off until I get some advice on what or what I should do next. The pic is of the post-surgery plant. The affected pseudobulb looked to be the oldest on the plant is not desicated at all, but its only leaf is starting to yellow and brown on the top edge of it. The other pseudobulb looks very good with 6 healthy-looking leaves as well as a very attractive set of blooms shown in the next pic.

What should I do from here? Should I have carved out the rot and dusted with cinnamon?

Here's a pic of the rest of the plant.

Cutting out the rot was the wise choice as rot can spread rapidly. I've had similar problems and cut out the rot and left the wound to air-dry...I didn't bother with cinnamon...I assume the cinnamon has the same effect as sulphur in preventing rot (?). You may loose the leaf from that pseudobulb but don't worry unless the rot is on the newest bulb. You could probably remove that rotted bulb alltogether and not affect the plant too much. What is the humidity in your growing area? If 50% or more, you don't even need to mist. I rarely mist in winter but I do in summer when plants are more actively growing. If you do mist, try to avoid getting the wound wet.

sounds like what you did is good. Make sure you cut well into clean tissue. I also spray/dribble hydrogen peroxide onto the wound until it stops fizzing. Then, I just air dry. If it's in an area that tends to get wet, or if the humidity is very high, I might put some sticky fungicide or triple action first aid cream (bactericide antibiotic stuff -just what I happen to have in the medicine cabinet) on the cut.

I took the plant to the nursery where I bought it. The "orchid expert (Greg)" was working at the information desk. He gave me a full refund on the plant, noted that the rot was most likely caused by a wound to the plant, where opportunistic fungus infected it. He then completely removed that pseudobulb, which only had one bad-looking leaf growing from it, showing me the contents of it and carefully repotted it for me to take it home. For anyone in the Portland, Oregon area, I can't say enough good words about the Portland Nursery. I spent at least 1.5 hours there talked to him about orchids, asking him questions, having him look over the two more I wanted to buy. The Oncidium is now in full bloom and I will post some pics some time tomorrow along with pics of the other two that are also blooming. I know repotting when an orchid is in full-bloom is a no-no, but I trust him with my plants. He's been growing them for over 30 years. Me==two weeks.

Todd, you are correct regarding cinnamin acting as anti-fungicide. The rot was only located on an old pseudobulb. Humidity here is not 50%, at least I really doubt it is, although my orchids do live in my bathroom. We may have a lot of rain here, but the Williamette Valley here in Oregon is not know for its humidity. I take that back. This state is the fungi-mold capital of the US since we have such a long rainy season which ends abrupty. For the next 3 months, it's dry as a bone, very warm, but quite dry.

As far as misting, with the entire wounded pseudobulb gone, no worries about protecting it.
When I did mist, I was sure to protect the wound.

Keyring, thank you, too, for the valuable advice. If (when) in the future I have to deal with a similar situation, good to know what to use. I also have some anti-fungal cream, but not sure that would be suitable for plants.

I used hydrogen on a phal when it had root rot, it didn't make it though. But I've had very good results with cinnamon on my new orchids. I like using it when I repot to dust the trimmed roots.

Oncs have that bulbs for a reason, to store water. So they don't need to be watered alot and I don't think they need alot of humidity either. People also say that keeping orchids in a bathroom is bad for them b/c of the rapid air changes. I've never tried them in a bathroom so I have no personal experience.

Here's a great care sheet on oncs for ya: (Go down and click on Oncidium located under Intermediate level:
http://orchidweb.org/orchids/culture/