Katja: I have found that infestations are somewhat weather dependant here in Senegal, and that most plants are most susceptible when stressed (not enough sunlight, too little
water, etc.). If you have the right plant in the right place and it's still getting attacked, try
soap spray: it is very effective for mealy bugs. I use a spoonful of potassium based
soap in litre of water. The soap dissolves the way coating they rely on for defense and protection from the elements. Usually one or two applications does the trick.
Most liquid soaps are potassium based. If you aren't sure, or are worried about the additives that might be in whatever liquid soap is available to you,
spray a trial amount somewhere inconspicuous and check for plant damage the next day.
