scale insect

any of numerous small, plant-sucking homopterous insects of the superfamily Coccoidea, the males of which are winged and the females wingless, often covered by a waxy secretion resembling scales.

[1830-40]

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Any member of several families of sap-sucking insects (order Homoptera) whose bodies are covered by a waxy shell (the scale).

The eggs are protected by the female's body or scale or a waxy filamentous mass. Scale insects may attack any part of a plant, but each species is host-specific. Many species are serious plant pests; others have commercial value. The lac insect is used in a red dye and in shellac. Cochineal, a red dyestuff, consists of the dried, pulverized bodies of females of the species Dactylopius coccus. See also cottony-cushion scale, San Jose scale.

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▪ insect

      any member of several families of insects (order Homoptera) that have a body covered by a protective waxy shell, often resembling scales or cottony cushions. The waxy covering is secreted by the insect after it settles on the plant where it will feed. Depending on the family, this scale may be hard and either smooth or sculptured, or it may be waxy and either smooth or filamentous. The eggs are always protected in that they are either embedded in a mass of waxy filaments or sheltered beneath the female's body or the scale she secretes. Upon hatching, the immature scales, known as crawlers, disperse over the plant before selecting a location where they will feed.

      Adult females are wingless and have reduced legs and antennae, whereas the males have one pair of delicate wings, well-developed legs and antennae, and no mouthparts. Each species of scale insect is restricted in its range of host plants. Scale insects may attack roots, bark, leaves, twigs, or fruits of plants. Serious plant pests are the San Jose scale, the oystershell scale, the scurfy scale, and the purple and red scale of citrus. Other species—including the cochineal insect, the lac insect, and the ground pearls—have some commercial value. See Chinese wax; cottony-cushion scale; ground pearl; oystershell scale; San Jose scale; scurfy scale.

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