Eriophyidae

Definition

A large family of minute, worm-shaped mites (Arachnida: Trombidiformes) commonly called gall mites or eriophyid mites. Adults possess only two pairs of legs—an apomorphic trait within Acari—and typically measure 150–250 µm. Most species are obligate plant parasites that induce galls, leaf curling, erinea, or other deformities in host tissues; a minority are vagrants that feed without causing visible symptoms. Dispersal occurs primarily via wind (anemochory). The family includes major agricultural pests (e.g., citrus bud mite, wheat curl mite) as well as agents used in classical biological control of weeds.

Etymology

From Eriophyes (type genus) + -idae (family suffix); Eriophyes from Greek erion (wool) + phyein (to grow), alluding to the woolly or felt-like erineum galls produced by some species.

Example

Aceria anthocoptes, an eriophyid introduced from Europe, has been deployed to suppress invasive Canada thistle (Cirsium arvense) in North American rangelands; conversely, the same family contains Aceria tosichella, vector of Wheat streak mosaic virus and a serious pest of cereal crops.

Synonyms

• eriophyid mites
• gall mites
• four-legged mites

Related Terms

• Acari
• Trombidiformes
• Prostigmata
• gall
• erineum
• phyllody
• Biological control
• mite vector
• anemochory

Usage Notes

Eriophyidae is a family name and takes singular grammatical agreement ("Eriophyidae is"). The common name "gall mite" is broadly applied but imprecise: not all eriophyids induce galls, and some non-eriophyid mites (e.g., certain Tarsonemidae) also cause gall-like symptoms. The two-legged appearance in adults (actually two pairs of legs, with posterior pair reduced or absent) distinguishes them from most other mite families. The enormous species diversity (>3,600 described, perhaps 30,000+ extant) makes Eriophyidae one of the most species-rich yet taxonomically understudied groups of Acari.