Origin:
Uncertain, but probably native to North America. It is found throughout the U.S. where it infests many species of oak trees.
Biology:
The female overwinters in the pit she has caused, beginning egg production beneath the wax cover in mid-spring, and continuing egg production for several months. The mobile crawlers emerge and quickly settle onto fresh twigs no more than 1 year old. They insert their mouthparts and become sessile at this point until the end of their life. They are more common on deciduous oaks, and are particularly common in oaks found in landscape settings.
Identification:
As the scale feeds on the bark of twigs the plant responds by creating a distinctive circular depression with the scale inside. In heavy infestations the feeding cause twig dieback and stunted growth. This scale does not produce honeydew. Only females are known, and the adult female is only 1.5 mm across, with the scale rounded, flat, and colored green, gold, or turning brown with age.
Characteristicts Important to Control:
If populations of the scale warrant control dormant or summer oils may be effective, as well as contact insecticides applied when the first instar crawlers are present. An IGR applied when crawlers are present also may be effective.
