Their eggs are laid in loose, cottony masses of wax. Mealybugs suck plant juices, and the constant drain on the sap supply for which they can be responsible results in slow growth of the plant as well as wilting between waterings. These insects can also be hand rubbed, washed off, or killed with an alcohol swab. Soil mealybugs can be treated by dipping the infested plant and pot in dilute malathion emulsion. 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.