Mealybugs live in roots also. I have root pruned and removed all soil and then dipped plant in solution to kill mealeys. All soil bagged and disposed. Pots cleaned and sterilized. Shelves and room cleaned. They can travel far. Plants will recover but if you miss one bug will start all over. Sometimes better to toss plants and propagate clean cuttings. Can win against mealeys with diligence.