Acanthococcus azaleae

Borchsenius, 1949

Azalea Bark Scale

Acanthococcus azaleae, commonly known as the azalea bark , is a felt in the . It is to Asia and has been to North America, Europe, and other regions through global trade. The feeds on azaleas (Rhododendron spp.) and related ericaceous plants, forming , 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 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 association—A. azaleae feeds primarily on azaleas and related Ericaceae, while A. lagerstroemiae attacks crapemyrtle (Lagerstroemia spp.). females produce , felt-like 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

to Asia. 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. or on ericaceous , unlike the crapemyrtle bark .

Host Associations

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

Behavior

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

Ecological Role

and pest. production creates resources for and may attract stinging such as and . Serves as for including (), (), 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 .

Similar Taxa

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

Misconceptions

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

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Sources and further reading