I'm confused. The first one looks like mealy bugs, but second one looks like rot. Hope someone can nail this, 'cause I'm stumped at the combination of symptoms.
Looks like young scale to me (I've been battling scale for a few months now myself)....they like the pseudobulb canes more than mealy's do. They wedge themselves in the ridges and munch away. Bayer Rose insecticide works well on them, but keep spaying every 5 days or so to kill the ones that hatch out. AND check all of your plants they spread like wild fire. Vigilance is the key to getting rid of them. (I learned that the hard way)
I use isopropyl rubbing alcohol 70% which you can pick up at any drugstore. I use it full strength on a Q-tip or cotton ball or I also have some mixed with water (about 1 to 1) in a spray bottle. Mealybugs turn brown the instant the alcohol touches them. I hope this works for you!