These microscopic mites feed on the foliar tissue of plants which causes them to form a gall or other deformation on their leaves. They transfer from plant to plant via wind, birds and flying insects. They are generally considered a parasite since they rarely kill plants.
- Their feeding causes the plants to deform which is mainly an aesthetic issue.
- Many Willow, Poplar and Mountain Ash are affected in Calgary.
- There are many types of eriophyid mite, which can cause different types of damage.
- The bud mite infests the developing buds and fruits of certain plants.
- The blister mite causes pockets to form in the internal leaf tissue.
- Gall mites produce an abnormal tissue growth called a gall.
- Rust mites cause a bronzing or silvering effect on the leaves.
Plants can live with large infestations of eriophyid mite, most of the damage is cosmetic. Since it is rarely fatal no control measures are recommended. If you feel you must do something, prune off the infected leaves and use dormant oil to smother the overwintering females.