Need help with mold killing my orchid roots!

[greenleaf]

I have a cattleya that I repotted 10 days ago. It had some mild root rot but I was able to clean off all the bad roots and repot it into new bark mix. It still had a sufficient amount of roots left and 5 very nice pbulbs. I watered it a week ago.

Anyways I didn't see the plant for a week and now I got back and I noticed that though the surface is dry, there's tons of water vapor and droplets inside the pot! And mold too! Cobwebby mold and green patches of mold! (It's in a 4" clear plastic pot btw.) I quickly unpotted the plant and noticed mold growing on the roots, and more roots rotting, looking like brown jelly!

Where did the mold come from? I used a newly opened bag of bark from Home depot. At first I did notice some white stuff on the bark but I poured boiling water on the bark as a precaution. What caused the mold? Should I spray with fungicide and what's the best brand of fungicide? What else should I do?

also I live in US near D.C. and humidity is low so I don't know why so much mold...and what I did wrong

thanks for the help!