I've had mealybug on some of my houseplants for a couple years now. Most of my plants seem to be immune, but a few have it pretty badly. I have a lot of succulents and they seem to get the worst case of mealybug (especially my jades and aloes).
|Aloe with mealybug|
Unfortunately, even the "safe" houseplant insecticidal soaps are not safe on succulents. I once lost a gorgeous, enormous jade plant (that I had owned for over a decade) after spraying it with insecticidal soap. I guess I should have done more research before doing the spraying, but I assumed it was safe for all houseplants. Instead, that beautiful jade started dropping all of its leaves, then sections of the stem started to fall off...eventually the whole plant collapsed. The loss of this plant was really upsetting!
From that point on, I've used a different tactic to combat the mealybugs...I just let them be. The infestation hasn't spread to any other plants, and the infested plants seem to do just fine (despite looking a little furry). I put most of my houseplants outside over the summer which seems to knock their numbers down. However, they always comes back when I bring the plants inside for the winter.
|Mealybugs on my potted rosemary. I just wash them off and eat it anyway!|