Discoloration on leaves of Oncidium (something eating them maybe?)

[butterfly_muse]

Good evening, everyone! Long time no chat! My orchids have been doing well lately, and I've even gotten a slew of reblooms going on right now.

Alas, though, this evening while watering one of my guys, I noticed that there is some brown discoloration on the leaves -- it almost looks like something is sucking the color right out of them? At the very tip of one of the leaves I found what looked like a tiny cobweb. <_<

Any idea what this might be, and how to remedy it? I would hate to spread it to my other orchids, including some new recruits I picked up at the Maryland Orchid Society sale on Saturday. O_O!

I have attached photos, any advice would be greatly appreciated!