Chaff scale

Definition

A common name for the armored scale insect Parlatoria pergandii (family Diaspididae), a polyphagous pest that infests leaves, fruit, and twigs of numerous woody plants including citrus, avocado, and ornamental shrubs. The name refers to the insect's thin, flattened, chaff-like waxy cover (test) that resembles wheat chaff, beneath which the sessile female feeds and reproduces. Infestations cause chlorotic spotting, premature leaf drop, and fruit blemishing.

Etymology

From the resemblance of the insect's protective waxy covering to chaff, the dry, scaly husks of cereal grains separated during threshing.

Example

In Florida citrus groves, heavy chaff scale infestations on grapefruit rind can render fruit unmarketable for fresh sale, requiring integrated management combining horticultural oil sprays and parasitoid wasps such as Aphytis holoxanthus.

Synonyms

• Parlatoria pergandii
• white chaff scale

Related Terms

• armored scale
• Diaspididae
• test
• citrus pest
• Parlatoria
• scale insect
• Integrated Pest Management

Usage Notes

The common name is primarily used in North American agricultural contexts; specialists typically prefer the scientific name Parlatoria pergandii to avoid confusion with other scale species. The term should not be confused with 'chaff' in the agricultural sense of grain processing waste, though the etymology connects the two. The species is sometimes called 'white chaff scale' when referring to lighter-colored biotypes or to distinguish it from darker armored scales.