Scale Insects
Scale insects, in case you are unfamiliar with them, are very different from your classical image of an insect. Most people envision insects as having 6-legs, usually with wings, and constantly motoring about eating things. Although scales are insects, their biology is unique enough that most people do not even notice that there are insects on their plants.
Scale insects are like the Little Pig that built the brick house. These pests erect a defensive structure that protects them from most dangers. There are many different kinds of scales. In fact most plants, at least in theory, can be attacked by one kind or another. Whether or not they are infected is another story. Adult scales range in shapes resembling a narrow fan, turtles, oysters, or little barnacles. Some even exude a cottony substance. Adults range in size from less than 1/16 inch to over 1/4 inch.
Generally, there are two kinds of scales: soft and armored. The soft scales exude honeydew (a sugary goo) and feed directly on plant juices. Armored scales burst plant cells open with their mouthparts and ingest the contents. They do not produce honeydew.
The Pine Needle Scale, Chionaspis pinifoliae (Fitch), has life cycle that is very typical of scales. This is an armored scale. It is most often found on Scots and mugho pines, but is not uncommon on other pines and spruces (Fig. 1). The eggs hatch in spring into small crawlers. These are very tiny immature scales that have legs and move about. You may need a magnifier to see them well. This is how a scale infestation spreads. Eventually the males will grow wings and mate with the newly matured legless, wingless females. After mating the males die. The females will stay put from here on out.
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