This scale insect is now widespread and common, especially in southern part of England. It is particularly noticeable on the branches and trunks of its host plants in early summer when the distinctive white egg masses are being produced. It causes little damage to its host plants but heavy infestations look unsightly.
Adult dark brown scales are flat and round in shape, about 4 mm across. They perch on the edge of white egg masses which are deposited on the bark. Immature scales seen on foliage are pale yellow and oval in shape.