Origin:
Native to Japan and China, but now well established throughout the U.S. and into Canada wherever suitable host plants are used in landscaping.
Biology:
A scale capable of infesting several kinds of ornamental shrubs, including pachysandra and bittersweet, but most often a serious pest on Euonymus. Heavy infestations can cause severe stress and dieback to the plant, or lead to the death of the plant. Mature females overwinter, deposit eggs beneath their wax shell in the early spring, and crawlers emerge in mid spring. This first generation completes development by early summer, and a second generation is common that is active until the early fall. In mild climates there may be 3 generations per year.
Identification:
A very small armored scale with a dark gray, elongate pear-shaped body about 1/16 inch long as the adult female. In heavy infestations entire twigs may be covered with the insects. The male scales often are highly visible in this species, as a narrow, white scale mixed in with the darker females. Male scale insects initially begin as tiny wasp-like, winged insects, but in this case they eventually become sessile on the plants as the females do, producing their wax shell.
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.
