Question
We live in The eastern part of Wisconsin -Two Rivers. We were trimming the dead branches from the tree and found what we thought was called scale from some things we read, but don't know what to do about it

Answer
Scale insects refers to a group of insects that vary in shape and form and can affect both hardwoods and conifers.

There are three types of scales (softbodied, hard-bodied, or armored scale).

A large population of scales can cause stunted tree growth, a weakening of the tree, and branch or crown dieback. Scales are usually a serious problem only in nurseries, seed orchards, and landscape trees.   

Scales go through three life stages: the egg, the nymph, and the adult. Many scales can only move about during the nymph stage, which is also called the crawler stage. As adults, these scales cannot move around a tree and stay in one place. Depending on the type of scales, adults usually have some form of outer covering, either a hard covering or a softer, waxy one.

In the spring, female scales lay their eggs underneath their bodies. The eggs hatch and the nymphs emerge and seek out a feeding site on the tree. Scales feed by sucking out plant juices and this is what causes damage. Nymphs eventually molt and become adult scales

Ususlly there is the presence of a sticky substance called honeydew. This is the excrement from the sap that the scales feed on. A sooty mold will grow on this honeydew.

If there are only a few scales present and there is no sticky honeydew, natural predators such as ladybugs will control the infestation.If there are good numbers then a spray should be used to control the scales.  


Insecticidal soaps are long chain fatty acids that kill susceptible insects through direct contact. Like horticultural oils, they require thorough coverage. Soaps leave no residue so repeated applications may be needed for some pests. These products may burn the foliage of sensitive plants, such as Japanese maple, so check the label for information about the plant species that you intend to treat.

A variety of natural and synthetic insecticides are labeled for use as sprays to control scale crawlers on landscape trees and shrubs. While the residual life of these products is generally longer than oils and soaps, timing, coverage, and precautions on damage to some plant species are very similar to those for oils and soaps.

?Systemic insecticides
Imidacloprid (Bayer Advanced Garden Tree & Shrub Insect Control Concentrate) is applied as a drench around the root zone of infested plants. This water soluble insecticide is taken up by the roots and transported throughout the plant where it is ingested by sap feeding insects. This provides a means of suppressing armored scales without reliance on sprays. However, it may need to be applied several weeks before crawlers are active for best results.