Arborvitae (Thuja)-Spider mite

Includes spruce spider mite (Oligonychus ununguis)

Pest description and damage Several species of spider mites can cause damage in deciduous, evergreen and coniferous ornamentals. Mites are all 0.02 inch or smaller. Nymphs are yellowish green and as they mature, they develop a grayish-black abdomen with tan-colored legs and head area. Spider mites damage leaf scales and fruit indirectly by feeding on leaves causing leaf stippling and bronzing that later turns brown. The reduction in photosynthesis causes loss of vigor.

For biology, life history, monitoring and management

See "Spider Mite" in:

Management-chemical control

See Table 1 in: