The adults of both sexes are winged and are usually covered with a white dust or waxy powder. First instars are active and called crawlers. Later instars are sissile and look like scales. They have piercing-sucking mouthparts which they use to suck sap from the leaves of plants. They also excrete large mounts of honeydew which sooty-mold grows upon.
Some whitefly species are serious pests of cultivated plants.
See Honeydew .