During the season, insecticide sprays will kill the crawlers. Insecticide sprays will not kill the scales once the cover is secreted. Usually aphids are considered a pest of the leaves. The feeding causes the tree to form knobby galls. This can occur on twigs and on the roots.
Heavy damage can reduce the vigor of the tree.
Woolly aphids are covered with a mass of long wax filaments. This gives them their common name. The above-ground forms can be controlled with insecticide sprays. These should be applied whenever colonies of the aphids are present. Root feeding colonies cannot be controlled.