Bark-feeding scale insect that can form high populations rapidly. Usually attacks cherries, plums, lilacs and other trees and shrubs. On the East End it has become a severe problem on privet. Easily seen as a white coating on trunk and limbs of tree. Causes yellowing and premature leaf drop and dieback. Can severely harm trees. May require treatment over several seasons. Spray treatment recommended but must be timed to the emergent crawler stages of the life cycle (3 times during growing season on Long Island) otherwise new crawlers repopulate the trees.