There are two types of scale insects, unarmored and armored. Many species become stationary when fully developed. The males usually pupate under a small, thin, transparent, flat scale, and emerge as tiny winged adults. Once the motile first-instar nymphs settle down on a plant, the females never move again. The males transform to winged adults as with the unarmored scales.
Scale insects suck sap from the plant, resulting in retarded growth and even defoliation.
Scales are more difficult to control than most pests of ornamental plants, and several applications at intervals of 3 or 4 weeks may be required to kill them all. The scales may remain attached to the plant after they die, but their dry bodies can be readily distinguished from the juicy ones of the living insects. If only dabbed with alcohol. The nymphs and pupae are soft, oval, flat, and resemble the unarmored scales. The nymphs are oval, thin, flat, semitransparent, and pale green, and bear a fringe of wax rods or filaments.