The calico scale (Eulecanium cerasorum) is species of scale insect. It is a common pest of a variety of woody landscape plants. It does not usually kill its host plant, however, it can severely weaken the plant, making it more susceptible to woodborers, drought and other stresses. Calico scale can be spread by windblown crawlers orcarried on the feet of birds between plants. They can also be spread by infested nursery stock.
This colorful white and dark brown calico scale is about 1/4 inch in diameter. It is brightest at maturity and darkens with age. The first-instar nymphs are pinkish in color becoming yellowish as they enlarge. Throughout the winter the immature females are oval, flattened, and light to dark brown with a hard waxy coating.
Calico scale’s host range includes dogwood (Cornus), honeylocust (Gleditsia), magnolia (Magnolia), maple (Acer), sweetgum (Liquidambar styraciflua), tuliptree (Liriodendron tulipifera) and ornamental fruit trees. It covers the branches and leaves of the host plant feeding on the phloem tissue. The plant may be covered in sooty mold as a result of the large quantities of honeydew produced by the calico scale. In large numbers, feeding can result in branch dieback.