Birch budgall mite

Birch budgall mite - Recent damage; proliferation of aborted buds
  • Latin name: Acalitus rudis (Canestrini)
  • French name: Phytopte des bourgeons du bouleau
  • Order: Acari
  • Family: Eriophyidae




Bud, Annual shoot

Damage, symptoms and biology

The birch budgall mite is a microscopic mite. The nymph and adult stages suck the sap from the twigs at the base of the buds, inducing the formation of rosette-like galls, which consist of clusters of aborted buds. On severely attacked birches, the abnormal profusion of buds causes a reduction in foliage density. The damage then becomes very apparent, particularly in late summer.

The birch budgall mite overwinters as a nymph in bark crevices or near buds and begins to emerge on the first warm days of April.

Life cycle (East of the Rockies)

Life cycle (East of the Rockies)
Stage/Month J F M A M J J A S O N D

Other information

When populations are large, the aesthetic value of ornamental trees may be affected. Early in the season, look for abnormal clusters of buds, and cut out and burn affected twigs.

Canadian Forest Service Publications

Birch budgall mite

Diet and feeding behaviour

  • Sap-feeding : Feeds on plant sap.
    • Piercing-sucking: Has specialized mouthparts for sucking the fluids from plants, thereby causing deformities or killing the affected plant sections.
Information on host(s)

Main host(s)

White birch

  • Birch budgall mite Old damage; abnormal bud proliferation
    Thérèse Arcand
  • Birch budgall mite Recent damage; proliferation of aborted buds
    Thérèse Arcand
  • Birch budgall mite Severely infested white birch; thin crown
    Paul Benoît
Date modified: