It's time to talk about scales. Not bathroom or fish scales, but the ones lurking in your landscape. Lurking may be a stretch. Scale insects have no discernable head or legs, live under a waxy covering and suck plant juices. Despite their resemblance to helmets, their feeding can weaken and even kill trees and shrubs. The tricky part about scale is they often go unnoticed until they reach high populations. In addition there are several different scale species with different life cycles.
Source: University of Illinois at Urbana-Champaign