Have you ever parked under a tree during hot weather, only to discover a few hours later some sticky sap is dripping from the tree? Do you have outdoor furniture, a swing set or a sidewalk that gets covered with black, sticky goop during the summer? If so, you have been a victim of a scale insect.
Scales are a large and diverse group of insects. They vary a lot in size (from 1/16 to 3/8 inch across) and appearance, but they all grow beneath a waxy covering that resembles a fish scale, hence the common name. This covering protects the insect underneath by shedding water (and pesticides), as well as providing a barrier from other species that might want to eat them. The waxy coating might be oval, dome-shaped, oyster-shell-shaped, resemble small mussels or have a fluffy cotton candy-like coating.