Reddened undersides are covered in whitish powder. Leaves later turn purple or red. Pick off and destroy affected leaves. Spray Benomyl or Sulphur . Red-purple spots on leaves.
Spots enlarge and show gray centers.
Spray Fruit Guard when spots appear and repeat twice at 14-day intervals. Do not spray during blossom time. Leaves are stippled and yellowish. They have a dirty appearance, dry out and drop. Small webs may be visible.