There are several other general types of aphids or aphid-like insects. This insect, which is easily characterized by the conspicuous woolly patches it forms, is particularly drawn to open wounds or pruning scars. Aphids that feed at the base of leaf buds cause the leaves to curl and thicken of deform the leaves. Aphids that feed on branches, twigs, or roots may cause galls or knotty swellings. Extensive feeding damage can cause severe galls to develop on twigs, branches, and roots.
Heavy populations produce a lot of honeydew, which leads to the development of sooty mold.
In the fall, aphids fly to elm and deposit overwintering eggs. In the spring, aphids return to other hosts, such as apple. Pine bark adelgid. They are easily recognized by the white, waxy, cottony covering that they produce. Trunks of heavily-infested trees often appear to be whitewashed.