San Jose scale

San Jose scale (Aspidiotus perniciosus), insect in the armored scale family. Although small as a pinhead, this insect causes mass destruction to a wide variety of trees and their fruit. The wind blows the scales from tree to tree, and upon arrival, they begin to eat a tree's sap. Native to China, they have been found throughout the United States and Canada since their discovery in the San Jose area of California around 1880. Oil spray and natural enemies such as the Chinese ladybird beetle help protect trees from this insect.

See also: Scale insect.