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Hawthorn Mealybug |
By Carl Wilson, Horticulturist, Denver Cooperative Extension
The hawthorn mealybug feeds on the sap of twigs and small branches.Heavy infestations
weaken plants and cause branch dieback. Sooty mold grows on the large amounts of honeydew
produced and greatly detracts from hawthorn 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.
Predators include three species of ladybeetle and green lacewing larvae. Control efforts
have proved difficult because the insect spends so much time under loose bark and in other
protected sites.
The best time to attempt to control hawthorn mealybug appears to be in early May when crawlers are moving from overwintering sites in bark crevices to feeding sites in twig crotches. Contact an arborist to arrange for sprays with effective insecticides. Dormant season oil sprays in winter may provide some degree of control but should be coupled with spring crawler sprays.
Photograph courtesy of Judy Sedbrook.
