Fungi? Mold? Bacteria?

[admsteiner]

Originally Posted by calvin_orchidL

Not too clear from the photos but you may have mealy bugs which manifest as nasty white fluff (the bugs are small and inside the fluff)..google mealybugs and see if that's what you have. Get rid of them ASAP as they really suck and will spread to everything. Safers End All works

Thanks! That was exactly the problem. Wiped off what I could see, found one of my trusty sprays that lists mealybugs and had a whirl. I'll be keeping a very careful eye over the next few weeks and pouncing whenever I see them...