Armored scales

Definition

A family of scale insects (Diaspididae, order Hemiptera) characterized by a hard, protective waxy covering—called a test or armor—that is separable from the soft body beneath. Unlike soft scales (Coccidae), the armor of diaspidids is formed from exuviae and wax secretions and remains fixed in place when the adult female is removed. The family includes major agricultural pests that feed on plant sap, often causing chlorosis, dieback, or transmission of plant pathogens.

Etymology

From the hard, shield-like waxy covering (test) that protects the insect body, resembling armor.

Example

The California red scale (Aonidiella aurantii) and San José scale (Quadraspidiotus perniciosus) are economically important armored scales that infest citrus and deciduous fruit trees; their circular, gray-brown tests are often visible on bark and fruit surfaces.

Synonyms

• Diaspididae
• hard scales
• diaspidid scales

Related Terms

• Soft scales
• scale insects
• test
• Crawler
• Coccoidea
• Mealybugs
• San José scale
• white peach scale

Usage Notes

The term is used both informally for the family Diaspididae and descriptively for any diaspidid individual. Specialists distinguish armored scales from soft scales (Coccidae) by the separable test and lack of honeydew production. The armor is not the insect itself but a protective structure; live specimens must be slide-mounted or carefully dissected from the test for identification. Some literature uses "hard scales" synonymously, though this can cause confusion with certain Coccidae that also form hard coverings.