This is a common and serious pest of evergreen euonymus, often causing defoliation and dieback. Pachysandra and bittersweet are also suitable hosts. There are two generations per year. Both sexes are circular, strongly convex, and dark gray or black. Mature scales have a central, light-gray, circular right which is visible with a magnifying glass.
Gloomy scale is a common and serious pest of silver maple and red maple.
It is also found on sugar maple, hackberry, elm, boxelder, sweetgum, redbud, buckthorn, gallberry, mulberry, and soapberry. Obscure Scale Mature scales are dark gray, often identical to the color of the bark. Crawlers tend to settle close together, resulting in patches of scales several layers deep. This is a serious pest which causes dieback of branches, limbs, and sometimes entire trees. Oaks, especially pin oak, are the primary host, but it has also been reported on chestnut, pecan, beech, English walnut, willow, maple, hickory, and other trees.