The adult female is armoured, pear-shaped, and flat, with a length of about 1/8 inch. The colors range from white to filthy grey. They resemble the closely related pine needle scale in appearance.
Males have a similar look but are significantly smaller.
The crawler stage is a deep purple color.
Host plant:
The most common hosts are aspen, cottonwood, and willow. Other known hosts include apple, hawthorn, mountain ash, and Prunus spp.
Damages caused by Scurfy Scale:
Scurfy scale feeds on twigs and branch sap. Large dirty-white crusts of the scale will be seen during relatively infrequent outbreaks, and contaminated regions of bark will be destroyed.
Life history and habits:
Female scurfy scales are flat, thin, greyish white, 1/8-inch long, and rounded on one side, giving them the appearance of a pear or an oyster shell. Females may deposit up to 80 eggs, a characteristic reddish-purple color. After she dies, they are kept beneath the female covering. The bug overwinters in the egg stage, with eggs emerging in late spring and becoming purple crawlers that roam around on plants before settling and feeding. The scale is usually found on the shady side of trees or under a dense canopy of leaves. Because the scurfy scale is firm, no honeydew is formed during eating. In Illinois, one to two generations are generated each year.
