Now, during the dormant season, is a good time to check woody plants for scale insect infestations. Scale insects are not the easiest to recognize because they are not only immobile, but are usually small and do not look like most other insects. Many of them resemble small, oval or circular sea shells. One is even called oyster shell scale because of its similar appearance. If you discover an infestation, plan to apply a dormant oil, which controls the scale by smothering it, in late winter. This oil is readily available at your local garden center.
There are many trees and shrubs that are host to scale insects. Some of the more common ones are camellias, apples, pears, maple, oak, and euonymus. A few scales will not harm plants. However, populations can increase dramatically once the growing season begins. Heavy scale infestations can seriously impede the healthy growth of plants and may lead to decline and eventual death. For more information about scale insects check out the following websites.