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Eriophyid mites (the crimson erineum mite) on sugar maple. Photo: Tawny Simisky
Scientific Name: 
Common Name: 
Eriophyid Mites
Growing Degree Days (GDD's): 
None available at this time.
Host Plant(s) Common Name (Scientific Name): 
Apple (Malus spp.; pearleaf blister mite, Eriophyes pyri)
Ash (Fraxinus spp.; ash flower gall mite, Aceria fraxiniflora)
Aspen (Populus spp.; poplar bud gall mite, Aceria parapopuli)
Beech (Fagus spp.; beech erineum mite, Acalitus fagerinea)
Birch (Betula spp.; birch erineum patches, Eriophyes spp.)
Black walnut (Juglans nigra; galls on shoots and leaf petioles, Aceria caulis)
Blueberry (Vaccinium spp.; blueberry bud mite, Acalitus vaccinii)
Boxelder (Acer negundo; erineum patches on foliage, Aceria negundi)
Eastern white pine (Pinus strobus; white pine sheath mite, Setoptus strobacus)
Elm (Ulmus spp.; elm fingergall mite, Aceria parulmi)
Hackberry (Celtis occidentalis; witches broom gall, Aceria celtis)
Hemlock (Tsuga spp.; hemlock rust mite, Nalepella tsugifoliae)
Honeylocust (Gleditsia spp.; honeylocust rust mite, Aculops gleditsiae)
Japanese camellia (Camellia japonica; orange camellia rust mite, Acaphylla steinwedeni)
Juniper (Juniperus spp.; juniper tip dwarf mite, Trisetacus juniperinus)
Lilac (Syringa spp.; lilac rust mite, Aculops massalongoi)
Maple (Acer spp.; maple spindle gall, Vasates aceriscrumena)
Mountain-ash (Sorbus spp.; leaf blisters caused by Tetraspinus pyramidicus)
Pear (Pyrus spp.; pearleaf blister mite, Eriophyes pyri)
Poplar (Populus spp.; poplar bud gall mite, Aceria parapopuli)
Privet (Ligustrum spp.; privet rust mite, Aculus ligustri)
Scotch pine (Pinus sylvestris; eriophyid mites in the genus Trisetacus)
Spruce (Picea spp.; spruce rust mite, Nalepella halourga)
Willow (Salix spp.; willow gall mite, Aculops tetanothrix)
Yew (Taxus spp.; taxus bud mite, Cecidophyopsis psilaspis)
Insect Description: 

Eriophyid mites are insect relatives in the Eriophyidae family. The majority of species of mite in this family are undescribed and many have complex life cycles that are yet to be fully understood. Eriophyid mites are tiny, often "carrot-shaped", and can only be seen with magnification. They typically have only two pairs of legs. Many are associated with plant foliage and live on host plant leaves.

Damage to Host: 

Some cause leaf bronzing or yellowing that is often referred to as "rust". Other species produce galls on the leaves, buds, or flowers of their host. They may be referred to as blistergalls, pouchgalls, bladdergalls, fingergalls, spindle galls, or felt-like patches often called "erinea" depending upon the species of mite involved and the shape of the gall that it induces production of on its host plant. Other species cause leaf-curling symptoms or witches'-brooming. Some eriophyid mites are involved in the transmission of certain plant viruses. (Keep in mind that not all galls are produced by eriophyid mites; certain species of aphids, adelgids, phylloxera, and psyllids also produce galls on their host plants.) Often the "damage" created by eriophyid mites is minorly aesthetic, and can be tolerated on the host plant. In some cases, depending upon the species of eriophyid mite involved, noticeable disfiguration of the tree or shrub parts affected occurs. 


Knowledge of the identity of the tree or shrub species is the first step in narrowing down frequently encountered gall forming organisms, such as the eriophyid mites. Many species will be specific to a single or limited number of host plants. Often due to their tiny size, these insect relatives go unnoticed until galls or other symptoms become evident on the tree or shrub. Monitor for off-colored foliage or leaf, bud, or flower abnormalities. If gall-forming insects are not detected, observe the material with a 10-20X hand lens. 

Cultural Management: 

Prune out and destroy witches' brooms or heavily galled sections of host plants, where practical. 

Natural Enemies & Biological Control: 

Depending upon the species of eriophyid mite involved, certain species of predaceous mites do attack these insect relatives. For example, predaceous mites in the family Phytoseiidae are reportedly common when privet rust mites (Aculus ligustri) are present (Johnson and Lyon, 1991). The natural enemies of eriophyid mites will be specific to the species of mite of concern.

Chemical Management: 

Abamectin (NL)

Carbaryl (L)

Horticultural oil (L)

Pyrethrins (L)

Pyrethrin + piperonyl butoxide (L)

Spiromesifen (L)


Chemical management options for eriophyid mites are available, however we would like to stress here that this type of intervention is often unnecessary. The species of eriophyid mite involved, and whether or not the damage it causes to its host significantly impacts the overall health of the tree or shrub, should be considered on a case-by-case basis. Often, eriophyid mites cause little more than aesthetic interest and chemical management is not necessary. In some cases, eriophyid mites can create galls or witches' brooms that seriously disfigure plants. However, the ability to tolerate the presence of these insect relatives should be evaluated depending on the mite involved and site-specific observations.

The host plant and the type of damage caused depends upon the species of eriophyid mite involved. Many miticides are ineffective at managing eriophyid mites. Mites sheltered and protected by galls will not be effectively managed by contact pesticides. 

Active ingredients that may be applied systemically include: abamectin (injection).

Make insecticide applications after bloom to protect pollinators. Applications at times of the day and temperatures when pollinators are less likely to be active can also reduce the risk of impacting their populations.

Note: Beginning July 1, 2022, neonicotinoid insecticides are classified as state restricted use for use on tree and shrub insect pests in Massachusetts. For more information, visit the MA Department of Agricultural Resources Pesticide Program.

Read and follow all label instructions for safety and proper use. If this guide contradicts language on the label, follow the most up-to-date instructions on the product label. Always confirm that the site you wish to treat and the pest you wish to manage are on the label before using any pesticide. Read the full disclaimer. Active ingredients labeled "L" indicate some products containing the active ingredient are labeled for landscape uses on trees or shrubs. Active ingredients labeled "N" indicate some products containing the active ingredient are labeled for use in nurseries. Always confirm allowable uses on product labels. This active ingredient list is based on what was registered for use in Massachusetts at the time of publication. This information changes rapidly and may not be up to date. If you are viewing this information from another state, check with your local Extension Service and State Pesticide Program for local uses and regulations. Active ingredient lists were last updated: January 2024. To check current product registrations in Massachusetts, please visit: .