If you are organic you have a real problem in our dry intermountain area of the west with this pest once it gets established in your area. The best organic defense for me (Reno,Nevada) has been the external spray "Surround" from Gardens Alive. It is a white powdery protectant film that coats the surface of the leaves and fruit and is an irritant to the pest. When used early enough in the Spring after petal drop it protects about 75%-80% of the crop on each tree. It wipes off of the ripe apples easily and is non-toxic. Great stuff ! Looks funny on the trees but it also helps with sunscald too.