The sooty mold fungus grows upon this honeydew, blackening the foliage, twigs, and bark. Soft scales generally have one generation per year. Soft scales infest many deciduous woody plants and some conifers. Elms, maples, and fruit trees are commonly infested. The crawler stage may be dispersed by wind and water as well as migrating birds, small mammals, larger insects, etc.
Scale insects have piercing and sucking mouthparts.
They reduce the vigor of their hosts by sucking plant juices. Bark and sapwood tissues injured by scale feeding gradually turn brown and die. Soft scales feed primarily on the woody parts of the host. In some species, however, the crawler stage feeds temporarily on the leaves but moves back onto the twigs before leaf fall. Twig dieback may occur from heavy feeding on the bark of branches and twigs.