Gall-mite
Guides
Acalitus
Acalitus is a genus of microscopic eriophyoid mites in the family Eriophyidae. Species within this genus are cosmopolitan plant parasites that induce gall formation on various host plants. Several species are significant agricultural pests, including Acalitus essigi and Acalitus vaccinii, which affect berry crops, and Acalitus phloeocoptes, which damages stone fruit trees. The genus exhibits narrow host specificity, with individual species typically restricted to particular plant genera or families.
Acalitus brevitarsus
Alder erineum mite
Acalitus brevitarsus is an eriophyid mite that induces distinctive galls on alder species (Alnus). The mite lives and feeds within erineum—dense mats of hair-like structures—on the lower leaf surface, causing pale, domed swellings on the upper surface. It overwinters in old cones and bark crevices during autumn. The species is known from Europe, ranging from Spain to Russia.
Acalitus ferrugineum
beech erineum mite
Acalitus ferrugineum is a microscopic eriophyid mite that induces erineum galls on the leaves of American beech (Fagus grandifolia). The galls appear as pale to light yellow patches that progress to reddish-brown later in the season. The species is known from the United States and Canada and has been documented in over 4,000 observations.
Acalitus phloeocoptes
Apricot bud gall mite, Plum bud gall mite, Almond and plum bud gall mite
Acalitus phloeocoptes is a destructive eriophyoid mite pest that causes bud gall formation on Prunus species, particularly apricot (Prunus armeniaca). The mite manipulates host plant hormones to induce gall development: cytokinin (zeatin) and auxin (IAA) drive rapid bud proliferation, abscisic acid (ABA) controls gall maturity, and reduced gibberellic acid (GA3) triggers lignification. Infestation results in delayed flowering, deformed foliage, poor fruit quality, stunted growth, and potential tree death. The species has four generations annually in studied populations, with overwintering occurring as adult females in galls, bark crevices, branches, and soil up to 3 cm deep.
Acalitus ruelliae
Acalitus ruelliae is a species of gall mite in the family Eriophyidae. This microscopic arachnid induces abnormal plant growths (galls) on its host plants. The species epithet indicates an association with plants in the genus Ruellia (Acanthaceae). Like other eriophyid mites, it is highly host-specific.
Aceria aceris
maple gall mite, maple erineum mite
Aceria aceris is a gall-forming eriophyid mite that infests maple species (Acer), producing distinctive erineum galls on leaf surfaces. The mite has a worm-like, elongated body with four legs and annular ridges typical of the superfamily Eriophyoidea. It is one of numerous Aceria species specialized on maple hosts, with populations often associated with specific maple species or varieties.
Aceria baccharices
Mule Fat Blister Mite, mulefat leaf-blister mite
Aceria baccharices is an eriophyid mite species native to North America that induces distinctive leaf galls on two host plants in the genus Baccharis. First described by Hartford H. Keifer in 1945, this microscopic arachnid creates warty, protruding galls on leaf surfaces that serve as protected nurseries for developing mite populations. The species exhibits strong host specificity, with populations in northern California associated primarily with Baccharis salicifolia and southern populations utilizing Baccharis glutinosa. Adults eventually exit the galls through anterior holes, which may remain visible on the leaf surface.
Aceria brachytarsus
pouch gall mite, walnut purse gall mite
Aceria brachytarsus is an eriophyoid mite species that induces leaf-pouch galls on walnut trees (Juglans spp.). Formerly classified as Eriophyes brachytarsus, this microscopic arachnid is known for producing distinctive bladder-like galls on foliage. The species has been documented in California, Iran, Spain, and Belgium.
Aceria calaceris
Rocky Mountain maple felt mite
Aceria calaceris, the Rocky Mountain maple felt mite, is an eriophyid mite that induces distinctive felt-like galls called erinea on maple leaves. This microscopic species was first described by Hartford H. Keifer in 1952 from Fallen Leaf Lake. It has a complex life cycle involving two female morphs—protogynes for reproduction and deutogynes for overwintering—plus a single male form. The species is found in the western United States and Canada, where it specializes on three maple species.
Aceria campestricola
Elm Leaf Gall Mite
Aceria campestricola is a gall-forming eriophyid mite that induces small pouch-like galls on elm leaves. First described in 1865, this microscopic arachnid overwinters in bark crevices before emerging in spring to attack new foliage. The species exhibits complex taxonomic history with related forms previously described under separate names based on gall morphology.
Aceria caulis
Black Walnut Petiole Gall Mite
Aceria caulis, the Black Walnut Petiole Gall Mite, is an eriophyid mite in the superfamily Eriophyoidea. Like other members of its genus, this species is a plant parasite that induces abnormal plant growth. The specific epithet 'caulis' and common name suggest association with walnut petioles, though detailed biological studies of this particular species appear limited in the available literature.
Aceria celtis
Witches' Broom Mite
Aceria celtis is an eriophyid mite in the family Eriophyidae that infests hackberry trees (Celtis spp.). The species is commonly known as the Witches' Broom Mite due to the distinctive gall-like growths it induces on host plants. Like other eriophyid mites, it is microscopic (approximately 0.2 mm), worm-shaped, and possesses only four legs. The mite is a specialized plant parasite with a narrow host range centered on Celtis species.
Aceria cephalanthi
Buttonbush Mite
Aceria cephalanthi, commonly known as the Buttonbush Mite, is an eriophyid mite in the genus Aceria. Eriophyid mites are minute, worm-like arachnids with four legs that are specialized plant parasites. Members of this genus typically infest specific host plants, with this species associated with buttonbush (Cephalanthus). Like other eriophyids, it likely has a short development period and lives in protected areas of the plant.
Aceria chondrillae
chondrilla gall mite, skeletonweed gall mite, rush skeletonweed gall mite
Aceria chondrillae is a gall-forming eriophyid mite specialized as a biological control agent for rush skeletonweed (Chondrilla juncea), an invasive herbaceous perennial. Native to the Mediterranean region and ranging from southeast Russia to Portugal, this deuterogynous mite induces leafy galls in host plant buds, causing stunting and reduced seed production. It was introduced to Australia in 1971 and has been released in North America for weed management. The mite exhibits high host specificity and completes its entire life cycle within galls, with populations declining markedly in winter and recovering rapidly in summer.
Aceria dina
Tupelo leaf edge gall mite
Aceria dina is a gall-forming mite in the family Eriophyidae, commonly known as the tupelo leaf edge gall mite. This species induces distinctive gall structures on the leaf edges of its host plant, Nyssa sylvatica (black tupelo or sour gum). Like other eriophyid mites, it has a worm-like, elongated body with four legs and measures approximately 0.2 mm in length. The mite is an obligate plant parasite with a highly specialized relationship to its host.
Aceria elongata
Crimson Erineum Mite
Aceria elongata, commonly known as the crimson erineum mite, is an eriophyid mite that induces distinctive erineum galls on the upper leaf surfaces of sugar maple (Acer saccharum). The galls progress from pale greenish patches to rich red-purple coloration as the season advances. This microscopic, worm-like mite has two alternating generations per year and is known from the eastern coast of the United States and Canada. At high densities, it can cause leaf distortion and premature leaf drop, though damage is generally not severe enough to require control measures.
Aceria erinea
Walnut Blister Mite
Aceria erinea is a gall-forming eriophyid mite that induces characteristic blister-like galls on the leaves of common walnut (Juglans regia). First described by Alfred Nalepa in 1891, this microscopic arachnid is a specialized plant parasite with a highly restricted host range. The mite's feeding activity causes distinctive erineum galls—fuzzy, felt-like patches on leaf surfaces. Like other eriophyid mites, it has a worm-like body with only four legs and undergoes rapid development, completing its life cycle in approximately one to two weeks under favorable conditions.
Aceria fraxini
Ash Bead Gall Mite
Aceria fraxini, commonly known as the ash bead gall mite, is an eriophyid mite that induces distinctive capsule galls on ash trees (Fraxinus spp.). This species exhibits a complex life cycle involving alternation of generations, with an overwintering generation consisting solely of parthenogenetic females (deutogynes) and a summer generation containing both sexes (protogynes and males). The mite is distributed across North America, where it is considered a minor pest of ornamental and native ash species.
Aceria fraxiniflora
ash flower gall mite
Aceria fraxiniflora is a North American gall mite that produces distinctive galls on ash trees, particularly on male flowers. Native to North America, it was first recorded in Europe in southeast Hungary in 2017 and has since spread rapidly across eight Central-Eastern European countries by 2023. The mite appears to be a strict specialist on North American ash species, with no records from native European ashes. Its rapid spread on invasive green ash has raised interest in its potential as a biocontrol agent, though its real impact on host fitness remains unquantified.
Aceria lantanae
Lantana Flower Gallmite
Aceria lantanae is a minute, worm-like gall mite in the family Eriophyidae, used as a biological control agent against the invasive weed Lantana camara. It forms characteristic flower galls on host inflorescences. Released in South Africa in 2007, it has established patchily with variable success. Its performance is determined primarily by host-plant variety rather than climatic factors, showing significant differential susceptibility across L. camara varieties.
Aceria mackiei
Live Oak Erineum Mite
Aceria mackiei, commonly known as the live oak erineum mite, is an abundant eriophyoid mite that induces distinctive leaf-blister galls on several species of live oak. This mite is notable for its unique ability to form galls on oaks belonging to both the black oak group and the intermediate oak group, a trait not shared by other eriophyoid mites. The species is widely distributed across western North America and was previously classified under the genus Eriophyes.
Aceria negundi
box elder pouch gall mite
Aceria negundi, commonly known as the box elder pouch gall mite, is an eriophyid mite that specializes on box elder (Acer negundo). This microscopic arachnid induces characteristic pouch galls on its host plant. Like other members of the Eriophyidae, it has a worm-like body with four legs and is among the smallest plant-parasitic mites, measuring less than 0.2 mm in length. The species has been observed across a broad geographic range with over 4,700 documented observations.
Aceria nyssae
Black Tupelo Gall Mite
Aceria nyssae is an eriophyid gall mite that induces distinctive leaf curl galls on Nyssa sylvatica (black tupelo, sour gum). The mite's feeding activity causes leaf margins to curl inward, forming hollow pockets that shelter the mites and their eggs. This species exemplifies the highly specialized host relationships typical of Eriophyoidea, where individual species are often restricted to a single plant host genus. The galls are most evident on young leaves at branch tips during the growing season. Like other eriophyid mites, A. nyssae is extremely small and difficult to observe directly, with populations typically assessed through gall symptoms rather than mite counts.
Aceria paracalifornica
California Sagebrush Gall Mite
Aceria paracalifornica, commonly known as the California Sagebrush Gall Mite, is a species of eriophyid mite in the family Eriophyidae. As a member of the superfamily Eriophyoidea, it is a worm-like, four-legged mite that parasitizes plants. The genus Aceria includes numerous species that cause distinctive plant deformities including galls, witches' brooms, and leaf distortions. The specific epithet "paracalifornica" suggests a close relationship to or similarity with A. californica, a species associated with California sagebrush (Artemisia californica). Eriophyid mites in this genus are highly host-specific, typically specializing on a single plant species or genus.
Aceria parapopuli
Poplar Budgall Mite
Aceria parapopuli is an eriophyid gall mite that specializes on Populus (poplar/cottonwood) hosts. Research demonstrates that this mite exhibits genetic divergence driven by hybridization in its host plants, with distinct ITS1 sequence differentiation across multiple cottonwood hybrid zones. The species serves as a model for understanding how plant hybrid zones function as essential habitat and evolutionary drivers for dependent herbivores.
Aceria parulmi
Elm Finger Gall Mite
Aceria parulmi is an eriophyid mite species commonly known as the Elm Finger Gall Mite. It is a plant-parasitic mite that induces distinctive gall-like structures on elm leaves. Like other members of the genus Aceria, it has a worm-like, elongated body with four legs and is extremely small, typically less than 0.2 mm in length. The mite is specialized to feed on elm species (Ulmus), causing characteristic finger-shaped galls on leaf surfaces.
Aceria theospyri
persimmon leaf blister gall
Aceria theospyri is a gall-forming eriophyid mite that produces distinctive leaf blister galls on persimmon (Diospyros virginiana). As a member of the superfamily Eriophyoidea, this microscopic mite has a worm-like, elongated body with only four legs. The species is highly host-specific, feeding exclusively on persimmon and causing characteristic blister-like deformities on leaves. Like other eriophyid mites, it has a short development period allowing rapid population buildup. The mite represents one of thousands of specialized plant-parasitic mites in this ancient lineage that radiated over 200 million years ago.
Aceria trichophila
Aceria trichophila is a species of eriophyid mite in the family Eriophyidae. Eriophyid mites are minute, worm-like plant parasites characterized by their elongated bodies and reduced leg number. Like other members of the genus Aceria, this species is likely specialized on a specific host plant or narrow group of related plants, reflecting the highly host-specific nature of Eriophyoidea. The species has been documented through iNaturalist observations but detailed biological information appears limited in published sources.
Aceria trinema
Aceria trinema is a species of eriophyid mite in the family Eriophyidae. Like other members of the genus Aceria, it is a minute, worm-like mite with a highly reduced body plan adapted for living in confined spaces on plants. Eriophyid mites are among the smallest arthropods, with some species measuring less than 0.1 mm in length. The genus Aceria contains numerous species that are specialized plant parasites, many of which cause distinctive damage symptoms including galls, leaf curling, and witches' brooms on their host plants.
Aceria triplacis
Aceria triplacis is a species of eriophyid mite in the genus Aceria, family Eriophyidae. Like other members of the superfamily Eriophyoidea, it is a minute, worm-like, four-legged mite. Eriophyid mites represent one of the largest lineages of plant-parasitic arthropods, with conservative estimates of 100,000 living species. Most species in this group are highly specialized parasites of vascular plants, typically associated with specific host species or genera. The specific host associations and biology of A. triplacis have not been documented in published literature.
Aceria vaga
Aceria vaga is a species of eriophyid mite in the family Eriophyidae. Eriophyid mites are minute, worm-like arachnids with four legs that are specialized plant parasites. Many species in this group cause distinctive growth abnormalities on their host plants, including galls, witches' brooms, and leaf distortions. Aceria vaga is among the numerous eriophyid species that remain poorly studied despite the group's significant agricultural and ecological importance.
Aculops rhois
Poison Ivy Gall Mite, Poison Ivy Leaf Mite
Aculops rhois is an eriophyid mite species found in North America that induces distinctive galls on poison ivy and related plants. The species forms small red pouch galls on the upper leaf surfaces of its hosts, which include Toxicodendron species and some Rhus species such as fragrant sumac. The bright coloration of these galls makes the mite more conspicuous than many related Aculops species, contributing to its relatively frequent reporting despite limited formal study.
Aculops tetanothrix
willow gall mite
Aculops tetanothrix, commonly known as the willow gall mite, is an eriophyid mite species that induces gall formation on Salix (willow) species. The mite has been documented in parts of Europe including Belgium and Denmark. It is characterized by yellow body coloration with brown or sometimes orange markings. The galls it produces on willow foliage initially appear green and later develop red coloration.
Aculus minutissimus
Aculus minutissimus is a minute eriophyid mite, commonly known as a gall mite or rust mite. It is among the smallest arthropods, with a worm-like body and only two pairs of legs in the adult stage. Species in this genus are frequently associated with specific host plants, though detailed host records for A. minutissimus remain limited. The mite is known from numerous observations, suggesting it is relatively widespread but easily overlooked due to its microscopic size.
Eriophyes betulae
Birch gall mite
Eriophyes betulae is a gall-forming eriophyid mite that induces characteristic galls on birch trees (Betula species). The mite is microscopic, worm-like in body form with only two pairs of legs—diagnostic features of the Eriophyidae family. It has been documented in Denmark and other parts of Europe. Like other eriophyid mites, it feeds on plant tissues and manipulates host growth to create sheltered feeding structures.
Eriophyes cerasicrumena
Black Cherry Leaf Gall Mite
Eriophyes cerasicrumena is a gall mite in the family Eriophyidae that induces distinctive spindle-shaped galls on black cherry (Prunus serotina) leaves. The species was formerly classified under the genus Phytoptus. The galls serve as a food source for caterpillars of the cherry gall azure butterfly (Celastrina serotina), which consume both gall tissue and the mites themselves. The species is documented across eastern North America with over 8,600 observations.
Eriophyes emarginatae
Plum Finger Gall Mite
Eriophyes emarginatae is a gall-forming eriophyid mite that induces distinctive finger-like galls on Prunus species. The species was formally described by Keifer in 1939 with detailed morphological characterization. It is commonly known as the Plum Finger Gall Mite based on its host associations and gall morphology. The mite is distributed in parts of Europe and North America.
Eriophyes leiosoma
Lime Felt Gall Mite
Eriophyes leiosoma is an eriophyid mite species in the family Eriophyidae. The genus Eriophyes contains species associated with plant galls and deformities, including economically significant pests of fruit crops. Some Eriophyes species, such as E. dimocarpi, are known to cause witches' broom disease in longan (Dimocarpus longan) through toxic saliva that induces curled, malformed shoot growth. E. leiosoma itself has been recorded in Scandinavia (Denmark, Norway, Sweden).
Eriophyes mali
apple blister mite
Eriophyes mali is a microscopic eriophyid mite and a significant pest of apple orchards. It overwinters behind bud scales and initiates spring migration when midday temperatures exceed 10°C, developing two generations per growing season. The mite induces characteristic blister-like galls on apple leaves through its feeding activity, reducing yield and fruit quality. Field studies in Ukraine have demonstrated that targeted insecto-acaricide applications can reduce mite populations by 72.9–93.3% and improve orchard productivity.
Eriophyes neoessigi
cottonwood catkin gall mite
Eriophyes neoessigi is an eriophyid mite species commonly known as the cottonwood catkin gall mite. It is documented on iNaturalist with 168 observations. The species belongs to the genus Eriophyes, which includes gall-forming mites that induce characteristic plant deformities. Unlike the related Eriophyes dimocarpi, which causes witches' broom disease in longan trees, E. neoessigi is associated with cottonwood (Populus spp.) and specifically targets catkins.
Eriophyes pyri
pearleaf blister mite, pear leaf blister mite
Eriophyes pyri is a gall-forming eriophyid mite that attacks pear (Pyrus), apple (Malus), and plum (Prunus). Females overwinter beneath upper bud scales, emerging in spring when average daily temperatures exceed 10°C. The mite induces characteristic blister galls on young leaves by feeding on phloem sap, completing three generations per growing season in temperate regions. Population management through targeted pesticide applications can reduce mite numbers by 75–94% and improve fruit yield and quality.
Eriophyes tiliae
lime nail gall mite, bugle gall mite, red nail gall mite
Eriophyes tiliae is a gall-forming eriophyid mite that induces distinctive tubular galls on lime (linden) tree leaves. The mite is less than 0.2 mm long and overwinters in bark crevices and around buds before colonizing foliage in spring. Chemicals released during sap-feeding trigger the formation of hollow, finger-like galls that range from yellow-green to red and reach up to 5 mm in height. The species has three recognized subspecies (liosoma, tiliae, nervalis) distinguished partly by gall positioning relative to leaf veins. Despite gall abundance, the mite appears not to harm host tree health.
Phytoptus laevis
Phytoptus laevis is a species of eriophyid mite, currently recognized as a synonym of Eriophyes laevis. The original description dates to 1889 by Nalepa. As with other members of Eriophyidae, this species is a minute plant-feeding arachnid. Distribution records indicate presence in Belgium, though detailed biological information remains limited.
Trisetacus
Trisetacus is a genus of eriophyoid mites (Eriophyoidea: Phytoptidae, historically placed in Nalepellidae) that are obligate parasites of coniferous trees. Species within this genus exhibit strong host specificity, primarily infesting members of Pinaceae and Cupressaceae. The genus includes species with diverse feeding habits: some inhabit needle sheaths, others infest foliage, buds, or seeds. Molecular phylogenetic studies have revealed a deep dichotomy within Trisetacus, with two major lineages distinguished by female genital morphology and host associations—one lineage associated with Pinaceae and another with Cupressaceae. Several species are significant forest pests, causing damage ranging from needle chlorosis and twisting to complete destruction of seed crops. The genus has been subject to taxonomic revision, with 22 species recognized from North America alone.
Trisetacus ramosus
Trisetacus ramosus is an eriophyid mite in the family Eriophyidae, a group commonly known as gall mites or rust mites. Species in this genus are associated with coniferous plants, particularly members of Pinaceae. T. ramosus has been reported in association with pine species, though detailed biological studies remain limited. Like other eriophyids, it is minute, worm-like, and possesses only two pairs of legs in the adult stage.
Vasates
eriophyid gall mites
Vasates is a genus of eriophyid mites (family Eriophyidae) that induce gall formation on host plant leaves. Species in this genus are associated with diverse host plants including maple (Acer), black locust (Robinia), and lupine (Lupinus). The genus includes at least three described species: V. aceriscrumena, V. quadripedes, and V. lupini. Males exhibit specialized mate-guarding behavior of quiescent female nymphs prior to their emergence.
Vasates aceriscrumena
maple spindle-gall mite
An eriophyid mite that induces distinctive fusiform (spindle-shaped) galls on maple leaves in the eastern United States. The microscopic mite is visible only through the galls it produces. Unlike the related maple bladder-gall mite, its galls are elongate rather than rounded. The species causes minimal harm to host trees despite the conspicuous galls.
Vasates quadripedes
Maple Bladdergall Mite, maple bladder-gall mite
Vasates quadripedes is an eriophyid mite known for inducing distinctive bladder-like galls on maple leaves. The species is native to North America and has been introduced to parts of Europe, including Britain where it was first recorded in 2002. It is associated primarily with silver maple, red maple, and sugar maple. The galls it produces are a reliable indicator of its presence and are more readily observed than the microscopic mites themselves.