Coccoidea

Coccoidea is a superfamily of small sap-sucking insects in the suborder Sternorrhyncha of the order Hemiptera. Commonly known as scale insects, members of Coccoidea live on plant hosts and are characterized by protective waxy coverings and often a sedentary adult female stage. The group comprises numerous families and thousands of species, many of which are significant agricultural and horticultural pests.

Most species begin life as mobile hatchlings called crawlers that disperse to new feeding sites. Female adults are often wingless and remain under their protective cover, while males may be winged or have reduced mouthparts and are primarily involved in reproduction. They feed by inserting a stylet into the phloem to extract sap. Their coverings range from soft, waxy shields to hard, scale-like plates that conceal the body.

Taxonomy varies with revision, but the major lineages include armored scales (Diaspididae), soft scales (Coccidae), and mealybugs (Pseudococcidae). Some classifications also include Margarodidae and related families within Coccomorpha. The diversity of life histories, wax production, and coverings is high among Coccoidea.

Ecology and economic importance: Scale insects occupy a wide range of plant habitats, from forests to urban ornamentals. They can cause direct damage by feeding and may excrete honeydew that fosters sooty mold. Several species are major pests in agriculture and horticulture and are also used commercially, such as the lac insect Kerria lacca, which produces shellac.

Management: Control methods emphasize monitoring crawlers, biological control with parasitoid wasps and predatory insects, and cultural practices to reduce infestations. Chemical control is complicated by the protective coverings, waxes, and the mobility of early life stages.