Help! I have these white spots on my pencil cactus. Anyone know why? I am located in North Alabama, USA.
It might be mealybugs. Look close, with a magnifying glass if you have one, and see if you find tiny fuzzy bugs.
Well, nothing I've ever read says to do that, but you can buy it in spray bottles (select the cheapest alcohol you can find) and that's what I have always done, on a few different types of plants. It's of course cheaper to dilute the alcohol and probably as effective. Or you can wet a Q-tip with alcohol and dab them. I'm not very patient with them and just grab the bottle and go at everything that looks anything like a mealy bug. My infected plant has a lot of leaves in several layers with a lot of places for them to hide, so I just manage to keep them sparce but not eradicated. If you can manage to remember to do it every few days for a few weeks, you might catch them all before they reproduce.