woolly apple aphids

Infestation of woolly apple aphids on crabapple. Photo: Whitney Cranshaw, Colorado State University, Bugwood.org

Updated: June 2, 2021

Key points

  • Woolly aphids are aphids that produce a covering of fluffy white wax.
  • One of the most common species found in landscapes is the woolly apple aphid (see photo above). It is most commonly found on crabapple feeding at the base of new shoots.
  • It prefers to suck the sap from roots, branches and twigs of apple, but may also be found on alder, elm, mountain ash, hawthorn, serviceberry, and Pyracantha.
  • Examine trees for bluish-black aphids covered with fluffy white wax on exposed roots, wounds on trunks and branches, and at the bases of new shoots on branches. 

Other species of woolly aphids include the woolly elm aphid (elm, service berry as alternate host), woolly elm bark aphid (American and slippery elm), beech blight aphid (beech), and woolly alder aphid (alder and silver maple).

beech blight aphids

Beech blight aphids. Photo: Steven Katovich, Bugwood.org

Management

  • Parasitic wasps usually control woolly aphids. However, if necessary large infestations can be reduced by spraying with horticultural oil or insecticidal soap.

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