Scale insects are small, non-mobile insects that attach themselves to the wood, foliage, and, sometimes, the fruit of trees. Scale is most common on new, tender, woody growth. When adult scale is attached to the tree, it often appears as crusty or waxy bumps on the tree and is often mistaken for part of the tree’s own growth, but it is actually an insect. The scale sucks sap from the tree and causes leaves to turn yellow and drop. Often, a sticky substance can be found near the scale or on leaves. This is a secretion from the scale called honeydew and it often acts as an attractant for ants or as a growth source for sooty mold.
In the spring or mid-summer, small, almost invisible nymphs emerge from under the female shells and move to infect new areas of the tree. This is the only time in the life cycle of scale that the insects move.
To control scale insects effectively and to limit damage, Horticultural Oil Insect Spray should be sprayed on the tree. The Horticultural oil serves to suffocate the scale and eggs. In the spring or early summer, if the crawling nymphs are present, spray the trees with Bug Buster Pyrethrin Insect Spray to prevent the new nymphs from further infecting the tree.