Crimson erineum mite

Infested sugar maple leaves Thérèse Arcand

French common name: Phytopte veloutant de l'érable
Scientific name: Aceria elongatus (Hodgkiss)
Kingdom: Animalia
Phylum: Arthropoda
Class: Arachnida
Order: Acari
Family: Eriophyidae
Partial list of synonyms:
- Aceria regulus (Hodge)
- Eriophyes elongatus Hodgkiss

Distribution

Quebec, Ontario

Damage, symptoms and biology

Crimson erineum mite, a microscopic mite measuring approximately 0.15 mm, punctures the leaf tissue, causing velvety patches to appear on the surface of the leaves. The patches, called erinea, range in colour from pale green to crimson. They are composed of numerous hypertrophic leaf hairs that resemble blisterlike galls and are caused by the feeding of the mites.

In heavy infestations, the upper leaf surface can be completely covered with these patches. The leaves then tend to become distorted and dry out, causing them to drop prematurely. However, the crimson erineum mite does not cause a loss of tree vigour since it is rare for all leaves to be infested.

The activity of the mites begins early in the spring when the adults feed on the developing leaves. The female deposits her eggs and the young nymphs also feed on the leaves. There is usually more than one generation per year, with the generations overlapping.

In July, the mites leave the galls upon completion of their development. Adults overwinter in bark crevices, on twigs or near buds.

Other information

Native to North America, the crimson erineum mite occurs in the eastern United States and Canada.

Populations vary dramatically from year to year and although the aesthetic value of ornamental trees may be affected, control measures are unnecessary.