Scale Insects

Gloomy Scale, Melanaspis tenebricosa (Comstock), Hemiptera: Diaspididae, Lepidosaphes ulmi (Oystershell)

The distinct adult females are ovel reddish-brown, with waxy fringe along body margin.

There are numerous host plants and are scattered Worldwide.

Cool temperatures are favored.

When present in large numbers, scale insects cause yellowing and premature drop of foliage. Young trees may be killed outright, older trees are so weakened that they are susceptible to borers, diseases, and drought. During egg-laying, females excrete honeydew covering the bark and leaves, which then becomes covered with sooty mold.

After feeding starts, adults remain immobile for most of their lives. Eggs are deposited from spring to mid-summer. Eggs laid in June hatch in July. First instar nymphs (crawlers) migrate to rough bark cracks to overwinter. Active development and feeding occur in spring. Some feed on leaves while others settle down to feed on twigs of small branches.