Origin:
Native to the Orient, but introduced into the western U.S. on imported plants.
Biology:
Immature scales overwinter as flattened scales that are not particularly noticeable. In early spring the females grow rapidly and ultimately may be nearly 3/16 inch in diameter as a completely round, ball-like wax cover. They are dark brown to mahogany in color. Honeydew production is extremely heavy when infestations are high, causing problems with layers of sticky material on surfaces below the trees and large numbers of ants feeding on the sweet material. In mid-spring eggs hatch and the orange mobile crawlers emerge, move to the undersides of leaves, and feed there through the summer. In the fall these nymphs then move back to stems, insert their mouthparts there, and become the sessile stage with increasing layers of wax over them. The male scales go into a pupa-like stage in late winter, resembling small, white grains of rice.
Identification:
This scale is quite obvious with its large size and very round, bead-like shape. The mature females are mahogany brown and about 3/16 inch in diameter. It infests many plants in the Rose family, such as pear, apple, or pyracantha, as well as other fruit trees like cherry, almond, and peach, and ornamentals such as pyracantha, hawthorn, and others.
Characteristicts Important to Control:
For ornamentals dormant or summer oils may be effective in killing the scales, as well as contact insecticides applied when the first instar crawlers are present. An IGR applied when crawlers are present also may be effective. A systemic applied to the soil can also provide effectiveness in killing the feeding scales. For food-bearing trees a registered insecticide needs to be used as a topical treatment.
