Saddled prominent is a green to brown or yellow caterpillar with a reddish brown spot on its back. It eats the leaves. No chemicals are listed because outbreaks of the insect are short-lived. At other times it is very rare.
Witch-hazel leaf gall aphid causes galls 1/2 inch long. The galls are green, sometimes with reddish tips, and are formed on the upper leaf surfaces. Natural enemies usually control this insect; hand picking and destroying infested leaves will also be helpful. Dormant oil applied before the plant grows will control this insect.
The spiny witch-hazel gall aphid causes galls 3/4 inch long with long, coarse spines. The galls are green tinged with red. Both this aphid and the previous one migrate to birch for part of their life cycle. Spray with dormant oil before the plants begin to grow in the spring.
Eastern tent caterpillar feeds on witch-hazel leaves. Removing the nest by hand will control the infestation.