Citricola scale

Definition

A soft scale insect (Coccus pseudomagnoliarum, family Coccidae) that is a major pest of citrus and numerous ornamental and fruit trees in warm temperate and subtropical regions. Adult females are oval, brown to grayish, and 2–4 mm long, often forming dense colonies on leaves, twigs, and fruit. Heavy infestations cause leaf yellowing, shoot dieback, honeydew secretion with subsequent sooty mold growth, and reduced fruit quality. Unlike armored scales, the citricola scale retains its legs and antennae as an adult and does not produce a separate waxy test.

Etymology

From Latin citrus (citron tree, citrus) + -cola (dweller, inhabitant), referring to its primary host association; "scale" from the protective covering typical of Coccoidea.

Example

In California's San Joaquin Valley, citricola scale populations often surge following mild winters, requiring integrated management combining parasitoid wasps such as Coccophagus and Metaphycus species with summer oil sprays timed to crawler emergence.

Synonyms

• Coccus pseudomagnoliarum
• gray citrus scale

Related Terms

• soft scale
• armored scale
• Coccidae
• Coccus
• citrus pest
• Sooty mold
• honeydew
• Crawler
• Integrated Pest Management
• parasitoid wasp

Usage Notes

Distinguished from the more globally widespread brown soft scale (Coccus hesperidum) by host preference, morphology, and biogeography; citricola scale is particularly damaging to citrus in California, Australia, and the Mediterranean. The common name is sometimes written as "citrus citricola scale" or confused with "citrus snow scale" (Unaspis citri, an armored scale). In IPM programs, monitoring for first-generation crawlers (typically May–June in the Northern Hemisphere) is critical for effective intervention.