There are many types and galls can be on the leaves or twigs. Most galls are harmless so chemical controls are not suggested. Scales of several types are controlled with sprays of dormant oil applied in spring. Use Orthene applied 2 to 3 times at 7 to 10 intervals when the crawlers are first seen. Diazinon, Sevin or malathion are used whenever the crawlers are present.
Aphids cause distorted growth and deposits of honeydew on lower leaves.
Spray small trees with Orthene, Diazinon, or malathion when aphids first appear. On large trees, predatory insects will often bring the aphid infestation under control. Boring insects are most likely to attack weakened or stressed trees. Newly planted young trees may also be attacked. No chemicals are available.