Scales usually are seen in the stationary stage as adults and aren't always identified correctly by homeowners. Scales can be observed on bark and needles. They feed by sucking sap from a tree. The tree suffers reduced vigor, needle drop and dieback in severe infestations. Some scales also excrete a sticky honeydew that attracts nuisance pests such as yellow jackets and other wasps.
All scales start as eggs that are laid underneath the mother scale.
Crawlers eventually settle on a tree, produce a waxy covering and settle in to feed. The crawler stage usually occurs from mid- to late spring and lasts one to two weeks. Control of scale is best targeted against the crawler stage. You can choose from many different insecticides to control scale during this time of their life cycle. Sevin and Malathion are some insecticide options.