Obscure Pests on Trees and Shrubs Scales, which are found on bark, twigs, leaves, fruit, and evergreen needles, resemble small, rather hard growths. Some are round, others are oval, some narrow, and some shaped like oyster shells. Most are brown or gray in color, blending very well with tree bark or plant material.
Scales range in size from the size of a poppy seed to the size of a split pea.
When clustered together, they can look like crusty patches. Scales are found on fruit trees, shade trees, evergreens, and ornamentals. In Montana, we often find scale on fruit trees, lilacs, plums, birch, elm, spruce, pines, and sometimes Douglas fir and green ash. Although they are immobile, scales are actually insects that construct a small, permanent protective cover over themselves. They live underneath these shells, sucking plant juices.