Diaspididae

Definition

The largest family of scale insects (Hemiptera: Sternorrhyncha: Coccoidea), comprising over 2,650 described species in approximately 400 genera, commonly known as armored scale insects. Members are characterized by females that secrete a hard, protective, often elaborate waxy covering—the 'scale'—incorporating exuviae from the first two nymphal instars, sometimes with fecal material and host-plant fragments. This armor is substantially more robust and waterproof than the coverings produced by other scale insect families, persists on host plants long after insect death, and renders Diaspididae significant agricultural and horticultural pests.

Etymology

From the genus name Diaspis (Greek: 'through' + 'shield') + the family suffix -idae

Example

The San Jose scale (Quadraspidiotus perniciosus), a notorious pest of fruit trees and ornamentals, belongs to Diaspididae; its circular, gray, armor-like covering can completely encrust branches, and the empty scales often remain visible for years after control measures have killed the insects.

Synonyms

• armored scale insects (common name)

Related Terms

• Coccoidea
• Sternorrhyncha
• scale insect
• Exuviae
• San Jose scale
• white peach scale
• oystershell scale
• biological control of scale insects
• quarantine pest

Usage Notes

Diaspididae is distinguished from other scale insect families (e.g., Coccidae, soft scales; Pseudococcidae, mealybugs) by the hardness and structural complexity of the female's protective covering, which is separable from the insect body beneath. The term 'armored scale' is sometimes applied more broadly but technically refers specifically to this family. Identification to species often requires slide-mounting and examination of microscopic characters of the adult female or second-instar exuviae retained in the scale; the durable scale covering itself is frequently used in field diagnostics and historical specimen records.