Thanks—good eye. I rubbed at the larger spots with a toothpick and they seem to have been casings of some sort. Certainly no evidence of anything currently alive. With my limited knowledge, I have to guess these are eggs, though. (I did find a dead larder beetle(?) in the tray.) Would you recommend ...

Hello cacti lovers. My opuntia subulata has developed these small white spots within the last week. They're contained to one of three stalks and seem to be limited to the bottom and middle of the plant (for now). I can rub them off and there is no trace of them left. Are these eggs of some kind? The...