Is there any way to get rid of nipple gall on a vernal witch hazel?
It is terribly unsightly. –E.K., Manteo, NC Answer: While unsightly, nipple galls pose no harm to the health of your witch hazels. The half–inch–high conical green swellings, sometimes tipped with red, are the handiwork of the witch hazel gall aphid (Hormaphis hamamelidis). This insect occurs in the northeast United States, west to Illinois, and south to North Carolina. In early spring, aphid eggs that overwintered on the twigs of witch hazel hatch. The young nymphs feed on the surfaces of the unfolding leaves with their piercing mouth–parts. The leaf responds to the injury by growing to create a pocket around the insect. Females produce winged young within these galls. The young aphids then escape through a small opening on the underside of the leaf, and by midsummer the galls are empty. These winged young fly to the leaves of birch trees and produce several generations of wingless aphids during the summer. These, however, do not cause gall formation as they feed on the birch leaves.
