I have a opuntia cactus that has tiny little white bubbles coming out of the glochids. The bubbles aren't liquid, they seem to be dry, and they aren't on every tuft, just a few on each pad. I'm worried they might be egg sacs from some bugs. (Haven't had a bug invasion though.) I've had the cactus for a couple years and never noticed this before, but then again I didn't look this closely before. What do you think?