Heavily infested plants grow poorly and may suffer dieback of twigs and branches. Occasionally, an infested host will be so weakened that it will die. During the winter the cottony maple scale is in the immature stage and is small, oval and flattened in shape, and pale green in color. During the warm temperatures of spring, the scale reaches maturity and, by late spring, the brown, elongate scale has a characteristic white, cottony egg mass attached to it. Eggs are laid in April and June and hatching occurs throughout the early summer.
Crawlers settle on leaves and stems.
Male scales complete development by fall and mate with the immature females. Before the leaves drop from the trees, the female scales migrate to the stems and twigs to overwinter. In spring the female reaches maturity and lays a distinctive cottony egg mass. There is one generation per year. Crawlers are usually out between June 5 and June 25 in Virginia.