Just Toss Plants Infested with Mealybugs
Mealybugs, those little “cotton balls” that collect in the leaf axils of your houseplants, are very difficult to control. So if you see any on one of your plants, the best advice is to… simply toss it in the garbage! Next, thoroughly clean the spot where the pot was located with a cloth soaked in soapy water, because often the female lays her eggs elsewhere than on the plant. Even if you want to keep the pot, it’s best it to place the dishwasher where the intense heat of the water jets will eliminate any hidden mealybug eggs.
You find yourself unable to throw out a living plant? First, try to get over this: it’s not a good habit if you want to be a successful gardener. If not, you can try to control them with rubbing alcohol. But not by dabbing every insect individually with a cotton swab dipped in rubbing alcohol, which is the usual trick you hear. That is simply a waste of time because you’ll only see the adults; the tiny larvae, barely visible even when in exposed spots, survive these treatments by hiding in cracks and leaf axils. Next thing you know, the mealybugs are back again.
Instead, try spraying the entire plant with a solution of 3 tsp (15 mL) rubbing alcohol, 2 tsp (10 ml) of concentrated insecticide soap and 2 cups (500 ml) of warm water. Be thorough: you need to get the solution into every nook and cranny. Repeat every 3 days as needed. That might work. But tossing the plant is still the safest bet.