Scurfy Scale (Chionaspis furfura)

From: Ostry, Michael E.; Wilson, Louis F.; McNabb, Harold S., Jr.; Moore, Lincoln M. 1988. A guide to insect, disease, and animal pests of poplars. Agric. Handb. 677. Washington, DC: U.S. Department of Agriculture. 118 p.

Importance- This insect sucks sap from leaves, branches, and trunks of Populus and various other tree species. Single trees or clumps of trees may become infested by a great number of scales, which kill shoots, branches, and occasionally the entire tree.

Look For: Dead and dying branches on trees. White to dirty gray, flattened, pear-shaped scales (one-eighth inch long) on the bark. Often in large numbers they appear as a whitish crust on branches and stems.

Cluster of scurfy scales on aspen Photo by Whitney Cranshaw, Colorado State University

Biology- Eggs overwinter beneath the female scale, and crawlers hatch in spring. Nymphs settle down on the bark and grow into adults by late summer.

Monitoring- Inspect trees for scales any time of the year. Scales will usually infest isolated trees or clumps of trees. Consider control only when 10 percent of the trees are heavily infested and many branches die.

Control:

• Prune and destroy infested branches.
• Spray individual infested trees or stands for the crawlers with an insecticide recommended for scale insects.