The hawthorn mealybug feeds on the sap of twigs and small branches.
Heavy infestations weaken plants and cause branches to die.
Sooty mold grows on the large amounts of honeydew produced by the bug, and greatly detracts from hawthorn's appearance. White, waxy clumps scattered among the bark scales of the trunk and large branches are another sign of hawthorn mealybug infestation. Much of the insect's life is spent on the bark and only the young or nymph stage feeds on the leaves. Because this insect spends so much time under loose bark and in other protected sites where insecticide is difficult to apply, this bug is difficult to control. Predators include three species of lady beetle and the green lacewing larvae.