The mites were definitely mobile, as I could see them crawling (and I mean crawling) all over the place:
I shot this right before I brought the rauschii inside for a thorough Isopropyl alcohol spraying. It came back outside earlier tonight, so that gave me the opportunity for preventative IPA spray on other cacti in case there could be mites evading detection. Some are the same plants that were attacked in June, while others which have been in the collection for 6 months or less have a known vulnerability to flat mites based on reports by more experienced growers. In the case of my rauschii, I didn't see any signs of damage before today, so the mites must've started up only in the last few days. Such being the case, I caught the infestation in its earliest stage -- and my vigilance is paying off.
Typically, flat mites thrive in a temperature range of 77–86F with high relative humidity. While these conditions haven't been met over the last few weeks, my latest experience is telling me that the pest can still exploit cacti when they're not in growth -- i.e. winter dormancy. Since my winter has been unusually warm up until now, perhaps a cool-down to more seasonal temps this week will be enough to keep further mite attacks from happening. However, I can't afford to be complacent. I'll keep a close eye on the situation, and I won't hesitate to reach for the IPA if the rest of winter warms up again.
No one enjoys going through mite attacks, but "vigilance" is a good watchword to remember. If I practice what I preach, I won't be scared about the possibility of pest mites anymore.
