Acanthococcus azaleae

Borchsenius, 1949

Azalea Bark Scale

Acanthococcus azaleae, commonly known as the azalea bark , is a felt scale insect in the Eriococcidae. It is native to Asia and has been introduced to North America, Europe, and other regions through global trade. The feeds on azaleas (Rhododendron spp.) and related ericaceous plants, forming white, felt-like coverings on bark. It was initially confused with the crapemyrtle bark scale (Acanthococcus lagerstroemiae), which was first identified in Texas in 2004 and later determined to be a distinct species. The azalea bark scale produces honeydew that supports growth and can cause branch dieback in heavy .

Pronunciation

How to pronounce Acanthococcus azaleae: //əˌkænθoʊˈkoʊkəs əˈzæli.i//

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Identification

Distinguished from the crapemyrtle bark (Acanthococcus lagerstroemiae) by plant association—A. azaleae feeds primarily on azaleas and related Ericaceae, while A. lagerstroemiae attacks crapemyrtle (Lagerstroemia spp.). females produce white, felt-like ovisacs that cling tightly to bark. When crushed, exude a pink or reddish residue. The lacks the broad polyphagy of A. lagerstroemiae, which has been recorded on more than a dozen plant .

Habitat

Associated with azaleas and other ericaceous ornamental shrubs in landscapes and nurseries. Thrives in temperate and subtropical climates where plants are cultivated.

Distribution

Native to Asia. Introduced and established in United States, Germany, Russia, Belgium, and Canada. Within the United States, present in the conterminous 48 states.

Diet

Phloem-feeding on azaleas (Rhododendron spp.) and related Ericaceae. Monophagous or oligophagous on ericaceous , unlike the crapemyrtle bark .

Host Associations

Rhododendron spp. - primary Azaleas and related ericaceous shrubs
Ericaceae - Broader -level association

Behavior

Females produce white, felt-like sacs (ovisacs) that enclose the body and eggs. Each female lays 100–300+ pink eggs. Nymphs hatch as mobile "" that disperse to new bark surfaces to settle and feed. Excretes honeydew during feeding, which accumulates on bark and surrounding surfaces and supports growth of black .

Ecological Role

Herbivore and plant pest. Honeydew production creates resources for fungi and may attract stinging insects such as and bees. Serves as prey for natural enemies including lady beetles (Coccinellidae), lacewings (Chrysopidae), and parasitic wasps.

Human Relevance

Economic pest of azaleas in ornamental horticulture. Heavy cause branch dieback, reduced flowering, and aesthetic degradation through accumulation. Misidentification with crapemyrtle bark has complicated management history.

Similar Taxa

Acanthococcus lagerstroemiaeCrapemyrtle bark , an pest in the United States. Distinguished by plant preference (crapemyrtle vs. azalea), broader polyphagy, and later introduction history (2004 in Texas). Originally misidentified as A. azaleae when first detected.
Eriococcus spp.Related felt scales in the same ; some historically confused taxonomically with Acanthococcus.

Misconceptions

Historically confused with Acanthococcus lagerstroemiae; early detections of crapemyrtle-infesting in Texas were initially attributed to A. azaleae before taxonomic clarification revealed a distinct, .