Birch budgall mite

Recent damage; proliferation of aborted buds Thérèse Arcand

French common name: Phytopte des bourgeons du bouleau
Scientific name: Acalitus rudis (Canestrini)
Kingdom: Animalia
Phylum: Arthropoda
Class: Arachnida
Order: Acari
Family: Eriophyidae

Distribution

Quebec

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.

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.