Plant-parasites
Guides
Aceria
gall mites, eriophyid mites, four-legged mites
Aceria is a large genus of eriophyid mites (family Eriophyidae) containing over 900 described species. These microscopic, worm-like arachnids are obligate plant parasites that induce distinctive plant growth abnormalities including galls, erinea, and witches' brooms. Some species are economically significant agricultural pests, while others have been deployed as biological control agents against invasive weeds. The genus exhibits extreme host specificity, with most species restricted to a single plant species or genus.
Aculus
Aculus is a genus of eriophyid mites (Eriophyidae: Phyllocoptinae) comprising numerous species that are predominantly plant-associated. Species in this genus exhibit diverse host relationships, with documented associations spanning at least 15 plant families including Rosaceae, Salicaceae, Fabaceae, and Hypericaceae. Most described species are vagrants on leaf surfaces, though some form galls or cause leaf deformation. Several species are economically significant agricultural pests, while others have been investigated for biological control potential against invasive plants.
Eriophyes
blister mites
Eriophyes is a genus of eriophyid mites known for inducing gall formation on host plants. Unlike most mites, adults possess only two pairs of legs rather than four. The genus includes economically significant pests such as Eriophyes dimocarpi, which causes longan witches' broom disease in Vietnam, and Eriophyes pyri, the pear leaf blister mite. Species feed by piercing plant cells to access sap, with saliva that triggers distinctive plant growth abnormalities including blisters, curls, and witches' broom formations.
Eriophyidae
Gall and Rust Mites, Gall Mites, Four-legged Mites
Eriophyidae is a family of microscopic plant-parasitic mites comprising over 200 genera and approximately 3,600 described species, though estimates suggest the actual diversity may exceed 100,000 species. Members are commonly known as gall mites or rust mites due to their propensity to induce gall formation or cause rust-like discoloration on host plants. These mites possess worm-like bodies with only two pairs of legs, distinguishing them from most other mites. They are obligate parasites of vascular plants with high host specificity, typically specializing on single plant species or genera. The family includes significant agricultural pests such as the coconut mite (Aceria guerreronis), garlic mite (Aceria tulipae), and bermudagrass mite (Aceria cynodoniensis), as well as species used for biological control of weeds.
Phytoptidae
Phytoptidae is a family of eriophyoid mites in the order Trombidiformes, comprising approximately 75 described species across 17 genera. These microscopic, four-legged mites are obligate phytophages that exhibit diverse life strategies including vagrant surface feeding, gall induction, and endoparasitism beneath plant epidermis. The family is primarily associated with angiosperms, though some lineages inhabit conifers. Notable genera include Phytoptus, Retracrus, Austracus, Novophytoptus, and Oziella. Many species are economically significant as agricultural pests of palms, hazelnuts, and other crops.