Blc. with black spots/yellow leaves

[etcherkate]

I don’t like the looks of this at all! Some time in the last week, my Blc. has developed sunken black lesions on a new growth. The rest of the plant looks fine, and none of my other orchids have the same symptoms.

I moved my 40 or so orchids out of the window sills and under lights a few months ago, along with some herb seedlings. The orchids have never been happier: all of the phals are in spike, as are a couple of Oncidiums. The only problem I’ve had is aphids on my basil and fennel. The affected plants have been moved to another area of the house while I pick the aphids off one by one. Aside from occasional gnats, I don’t see any bugs on the orchids.

My inclination is to cut the affected area of the Blc. off with a new razor and move it to another area of the house, where it won’t be happy with the lighting, but I won’t risk spreading the problem to other plants.

What do you think? Bacterial infection? Fungus? Thank you in advance for your help!