Lecanium scale (Lecanium spp.) and numerous other species
Pest description and damage Adult female scale live under a shell-like covering that may resemble a "volcano," "barnacle," "hemispherical bump," "cotton puffs," "oyster" or even flat, soft and naked, and within various dull colors and markings. They are often found attached along the branches, twigs, leaves or needles or even fruit. Most scale insects measure from 0.0625 to 0.25 inch long. Occasionally scale build up large enough numbers to cause damage to the host plant. These insects have piercing-sucking mouthparts that they inject into plant tissues to feed on plant juices. Large populations of scale can devitalize plants and retard growth, as well as discolor the foliage. Severe infestations can kill twigs. In many cases, large quantities of honeydew are produced, which makes leaves and fruit shiny and sticky. Sooty mold fungus may grow on the honeydew giving the plants a dirty, sooty appearance.
For biology, life history, monitoring and management
See "Scale insect" in: