Eriophyes aceris

Aceria negundi

Vasates quadripedes

Vasates aceriscrumena

Aculops rhois

Eriophyes laevis

Aceria baccharipha

Aceria brachytarsa

Aceria caulis

Aceria aloinis

Aceria sandorici

Aceria fraxini

Aceria calaceris

Aceria elongata

Aceria modesta

Aceria major

Aculus minutissimus

Aculus quinquilobus

Aceria dina

Aceria nyssae

Cenalox nyssae

Cenalox conyssae

Aceria spermaphaga

Eriophyes helicantyx

Aceria ceanothi

Eriophyes adenostomae

Eriophyes emarginatae

Eriophyes cerasicrumena (on-p-serotina)

Aceria cephalanthi

Phyllocoptes didelphis

Aculops tetanothrix

Aceria paramackiei

Aceria breakeyi

Eriophyes tiliae

Aceria parulmi

Aceria near-campestricola

Trisetacus batonrougei

Eriophyes mangiferae

Aceria microcarpae

Phytoptus avellanae

Eriophyes pyri

Eriophyes paraspiraeae

Aceria baccharices

Trisetacus pseudotsugae

Trisetacus sequoiae

Eriophyes lepidosparti

Aceria chondrillae

Acalitus essigi

Acalitus vaccinii

Aceria sheldoni

Aceria fraxiniflora

Trisetacus gemmavitians

Trisetacus campnodus

Trisetacus alborum

Trisetacus quadrisetus

Trisetacus neoquadrisetus

Trisetacus floridanus

Aceria cinereae

Aceria erinea

Aceria caliberberis

Aceria cynodoniensis

Aceria granati

Eriophyes aceris

Acer saccharinum

And in erineum on leaves of silver maple, E. aceris Hodgkiss is abundant. The erineum patches, which are on the undersurface of the leaves, are pale greenish or greenish yellow, often with a reddish tint, and later red. In July most of the erineum turns brown and becomes dry.

Eriophyes negundi

Hosts: Acer negundo

The galls are large, rounded, and peculiarly pouchtype. They develop on the underside of the leaf blade as thickened cavities filled with a dense mass of felty, whitish, unicellular hairs. They protrude on the upper side and have slightly wrinkled domes. Their dimensions are variable. The galls are solitary and widespread on the leaf blade but are not on the veins.

Range: NY, IL, Canada, OH.

Bladder galls on leaf upper surface., The mite causes a pouch gall type known as bladder gall, which is periodically common and abundant on the upper leaf surface of red and silver maples. The galls on the latter are variable in shape, rounded or elongate. Each has a slender short stem or neck. The length varies from 1.5 to 5 mm. They are solitary and are usually crowded and numerous at the basal part of the leaf blade in the angles between the larger veins. The exterior of the galls appears wrinkled and glossy. They change from yellowish green or dark green to pink, to brown, to black. The interior is hollow, and the exit hole, which is on the underside of the leaf, is lined with unicellular whitish hairs. In heavy infestations, the leaves become curled, form cylindrical rolls, and drop prematurely. The galls on red maple differ in size and form. They are smaller, I to 2 mm, somewhat beadlike, and without a basal constriction or neck. 
Vasates quadripedes is found on red and silver maples in the United States and Canada.

Another common and abundant pouch gall that develops on the upper surface of sugar maple leaves is the spindle or finger gall, which is caused by Vasates aceriscrumena. The gall is distinguished from that of V. quadripedes Shimer by its form, position, color, and texture. The galls are solitary, elongate, with pointed or truncate apices, or spindle shaped. They are variable in size, up to 5 mm in length, and tend to crowd at the apical half of the leaf blade. They vary from greenish tinged with yellow to pink, to crimson. The exit hole on the underside of the leaf has a tuft of unicellular hairs, but the interior of the gall is thin walled and lacks hairs. 

Specimens are found in galls through July on sugar maple in the Eastern United States and Canada. 


Infestation is common and typical of the leaf galls. It consists of puckered, irregular, rounded, or wartlike pouches affecting both upper and lower surfaces of the leaves. The galls are usually scattered about indiscriminately on the leaf blade. They range from green to pinkish, to red brown. Poison oak leaves are often so heavily attacked that they become visibly crinkled and distorted. 

Specimens were collected on poison oak in Oregon and California and on poison ivy in Ohio and Maryland. It has also been found on poison sumac (Rhus vernix L.) in Ohio. The mite is probably present throughout its host range.

These beadlike galls are particularly striking because they appear on both surfaces of the leaves. They are small, hemispherical, of variable size and are scattered singly or crowded alongside the midrib. The galls are firmly attached, with the exit holes on the underside. They are shiny externally and the interior contains fleshy tissue. They range from green to yellowish, to red, to reddish brown as they mature. A single leaf may carry numerous galls so that it becomes distorted and its growth inhibited. Although P. laevis is a common species on alder, little is known of its seasonal history and habits. Specimens were abundant in August. The hosts are Oregon or red alder, white alder, and mountain alder in California and hazel alder in Ohio and Georgia. 

This gall is known as Baccharis leaf blister, a pimplelike swelling that develops on both sides of the leaf blade, with the exit hole on the underside. Generally an infestation gives the leaf a pimply, blistered appearance. The galls vary in size and from greenish to yellow, to brown. The mites occur among the fleshy tissue in the galls and presumably leave the galls and migrate to the buds during unfavorable weather. The host plant is locally known as chaparral broom, a spreading evergreen shrub that occurs in coastal and inland hills in California and southern Oregon. The mite specimens were first collected in California in April. Eriophyes baccharipha should not be confused with two other eriophyids that infest Baccharis in California. They are Eriophyes calibaccharis Keifer, which occurs in the terminal buds of chaparral broom, and E. baccharices (Keifer), which causes irregular, wartlike, rough-looking galls on the upper surface of the leaves of seep willow (Baccharis glutinosa Pers.) and mule-fat (B. viminea D. C. [salicifolia]).

The pouch galls induced by this mite on the upper surface of the leaves invariably appear at random between the lateral veins and on the midrib. The galls are often solitary, 3.6 mm in dimension, irregularly globular, and shiny with roughened surface. They range from green to yellowish green with red-dish or brown tinge. The interior of the gall, which becomes red as it matures, consists of multicellular structures, as shown in plate 6, E. Galls at times are numerous on some trees, causing considerable distortion to the foliage. 

This is an exceptionally interesting and beautiful pubescent gall, often brightly colored, passing from greenish through pink and crimson to reddish brown. The gall most frequently develops as an irregular, solid, hard mass on the leaf petiole. It is often solitary and variable in size. The exterior is covered with a dense mass of silky, unicellular, erineumlike hairs (see pl. 7, A). The gall tends to be large and to spread to and partly envelop the stem and leaf. The affected structure is greatly distorted and twisted, and leaflets fail to develop. This mite was found infesting black walnut in New Jersey and Pennsylvania in July-August. It is probably distributed throughout the range of its host from Ontario to Massachusetts and south to Florida and eastern Texas.

An affected plant shows a remarkable proliferation of unsightly, irregular outgrowth, clustered densely on the surface of the leaf blades or in leaf axils. The infestation may be con-fined to the base in the leaf axils as bunched, greenish, tiny-to-large globular sprouts or as a lumpy, rough-looking thickening in the form of wartlike growths from the base of the leaf blade extending to the tip. The longitudinal pattern of growth follows that of the lanceolate shape of the leaf. It ranges from yellowish to brownish, to green tinged with yellow. The mites also attack the inflorescence and cause galled blooms. This eriophyid attacks golden-tooth aloe, spider aloe, and star cactus or wart plant in southern California and Florida. It is probably found wherever these plants are grown. 

This is an unsightly pouch gall that develops on the underside of the leaf blade as a concavity filled with erineum and on the upper side as a rounded outpocketing with irregular puckered domes. The pouch is greenish, becoming blackish, and the erineum turns brownish at maturity. The galls are variable in size and are frequently coalesced and crowded, giving a lumpy appearance to the leaf blade. Eriophyes sandorici has been found only on santol of the mahogany family Meliaceae, a tropical tree with edible fruit from the lndomalayan region and Mauritius. 

The galls on the upper surface of ash leaves are unmistakable and often particularly numerous on the terminal leaves. They are small and solitary, somewhat reniform in shape, and generally scattered at random on the lateral veins. Their greenish-yellow color and shape give a striking effect on an infested leaf. Specimens were found in galls on leaves of white, Oregon, and green or red ash in California, Wisconsin, Virginia, New York, Vermont, and Canada. In Europe, Eriophyes fraxinicola (Nalepa), a closely related species of E. chondriphora, makes similar galls on leaves of European ash (Fraxinus excelsior L.). 

Eriophyes calaceris

Hosts: Acer glabrum

This is a colorful and impressive erineum on maple leaves caused by Eriophyes calaceris in the Western United States. The erineum growth is pustulelike, consisting of a brightly colored aggregation of tiny papillae. Each papilla is filled with colored fluid, and when magnified it has a rounded or capitate tip. The erineum appears on the upper surface of the leaf and is thickest from the apical half to the edge of the blade, missing the larger veins. It ranges from greenish yellow to pink, crimson, and purplish red. The infestation may be wide-spread on some trees.

The life history involves alternation of generations. The mites continue to colonize the erineum until September and then migrate to stems or twigs and bark crevices. Deutogynes overwinter in bark crevices and then move to newly developing buds in the spring. The inquiline eriophyids Aculops glabri (Keifer) and A. paraglabri (Keifer) are frequently in the erineum. Aculops paraglabri was recently found to be the overwintering form (deutogyne) of A. glabri and is therefore a synonym.

This mite was found abundant on Rocky Mountain maple in September in California. It is probably generally distributed throughout the range of the host plant from Alaska to California and east to South Dakota and New Mexico. Eriophyes calaceris may be confused with E. elongatus Hodgkiss, which commonly infests sugar maple (Acer saccharum Marsh.) in the Eastern United States. In addition to the differences in morphological structures, the erineum growths caused by each species are distinguished by their position, form, color, and density. 


Eriophyes elongatus

Hosts: Acer saccharum

Hodgkiss distinguished Eriophyes elongatus and E regulus, which cause the familiar glossy crimson erineum on the leaves of sugar maple. According to Jeppson et al. (1975), the latter species is a synonym of E. elongatus. The colorful erineum on sugar maple is remarkably similar to that produced by Eriophyes calaceris (Keifer) on Rocky Mountain maple (Acer glabrum Torr.). It is one of the most attractive and brilliant growths on the leaf surface. 

The pustulelike patches, at first greenish white and later becoming crimson or purplish, are generally scattered on the upper surface of the leaves. Close examination of the erineum patch shows an aggregation of tiny, rounded, capitate papillae that contain red fluid. The density of the erineum is variable. Occasionally the growth becomes extremely abundant and causes leaf distortion and premature leaf drop.

Eriophyes modestus

Hosts: Acer saccharum

In New York, Hodgkiss (1930) reported an uncommon greenish erineum on the underside of sugar maple leaves caused by Eriophyes modestus. The erineum later changes to brownish or blackish. 


Eriophyes major

Host: Acer rubrum

In addition to bladder galls, Hodgkiss (1913) described four species of eriophyids that are associated with erineum on leaves of red maple in New York. They are Eriophyes major Hodgkiss, E. minutissimus (Hodgkiss), E ornatus Hodgkiss [now a synonym of E major], and E quinquilobus (Hodgkiss). 


Eriophyes minutissimus

Hosts: Acer rubrum

In addition to bladder galls, Hodgkiss (1913) described four species of eriophyids that are associated with erineum on leaves of red maple in New York. They are Eriophyes major Hodgkiss, E. minutissimus (Hodgkiss), E ornatus Hodgkiss [now a synonym of E major], and E quinquilobus (Hodgkiss). 


Eriophyes quinquilobus

Hosts: Acer rubrum

In addition to bladder galls, Hodgkiss (1913) described four species of eriophyids that are associated with erineum on leaves of red maple in New York. They are Eriophyes major Hodgkiss, E. minutissimus (Hodgkiss), E ornatus Hodgkiss [now a synonym of E major], and E quinquilobus (Hodgkiss). 


Eriophyes dinus

Hosts: Nyssa sylvatica

Two species of Eriophyes infest tupelo. Eriophyes dinus is responsible for the irregularities of the leaf margin, which consist of thickened rolled edges with one or two windings, and the transforming of the leaf tip into a twisted or spiral tube. At first the colonized areas are the same color as the rest of the leaf, later becoming reddish, and finally brown. The thickness of the leaf roll is variable, and the whole length of the leaf margin may become infested, producing an attractive crinkly, wavy leaf. Rolled edge leaf sometimes has beadlike galls colonized by beadlike galls colonized by Eriophyes nyssae. These galls, which also occur on the upper surface of the leaf, are small and may be solitary or coalesced. 

Eriophyes nyssae

Hosts: Nyssa sylvatica

Two species of Eriophyes infest tupelo. Rolled edge leaf sometimes has beadlike galls colonized by beadlike galls colonized by Eriophyes nyssae. These galls, which also occur on the upper surface of the leaf, are small and may be solitary or coalesced. 

Cenalox nyssae

Hosts: Nyssa sylvatica

[Galls] caused by C nyssae are small, rounded pockets filled with erineum; the galls appear alongisde the midrib at angles of lateral veins [and] form slight swellings on the upper surface of the leaves.

[T]wo distinctive species, Cenalox nyssae and C. conyssae also infest túpelo. Specimens were found recently on the underside of the leaves in galls along the midribs and veins. The simple distinctions of the two galls concern their form, position, and texture. Those caused by C. nyssae are small, rounded pockets filled with erineum; the galls appear alongside the midrib at angles of lateral veins. <b>The C. conyssae galls are rough, open pockets filled with fleshy lobes, and they appear alongside the veins. Both galls form slight swellings on the upper surface of the leaves.</b>

[no photo provided of C. conyssae] 

Catkin gall [on Juglans hindsii].  The mites infest almost every male flower in the drooping catkins. There is considerable malformation with excessive development of individual flowers, each resembling a miniature cauliflower head. Galled catkins on a tree are conspicuous from the ground as a green or dirty brown, blackish, lumpy mass. They begin to deteriorate in July, becoming heavily infested by the mildew fungus. Infested catkins often remain attached to the tree so that galls can be seen throughout the season. The mites seem to have the effect of prolonging the life of the catkin. Although female flowers are heavily infested with mites, they do not show signs of malformation. 

The male, protogyne, and deutogyne were found inhabiting galled male catkins and female flowers during June-July. The life cycle of this mite has not been observed. Eriophyes spermaphaga was recently discovered on catkins of Hind's walnut from California. No collection has been made in other areas. This species should not be confused with Eriophyes neobeevori Keifer, which causes similar injury to catkins in California walnut {Juglans californica S. Wats.) in southern California.

This is a beautiful marginal roll gall of bracken. When seen under a microscope, it looks like a delicate, pale, lime-green lace border on the underside of the pinnule. The first indication of infestation is a characteristic discoloration and distortion of the pinna. The affected pinna is generally yellowish, later turning brown. The galled pinnules are abnormally small and distorted, with a thickening of reflexed margins. The indusium, which becomes enlarged, contains mites and lime-green erineum like hairs. The infestation occurs in June-July.

These are unique galls that develop on the underside of leaves. They are small, rounded, solitary, or clustered, and they are scattered haphazardly over the leaf blade and along the leaf margin. Their positions are marked on the upper surface by small, white spots, each with a tiny escape hole. The presence of white spots against the green background of the upper leaf blade makes the galls striking and easily recognizable. The galls are of the same whiteness as the underside of the leaf blade. Frequently the plant is heavily galled. These interesting and beautiful galls are caused by Eriophyes ceanothi.

Eriophyes ceanothi occurs on redroot, an evergreen shrub found from British Columbia to Colorado and California. Specimens of mites were first collected in Oregon and subsequently in California.

This typical pouch gall, which is distinctive and attractive, occurs on a tiny, narrow, elongate leaf blade of a rosaceous plant. The galls are hemispherical with roughened, puckered domes; they are solitary and rarely coalescent. There are seldom more than two pouches on one leaf. Initially the galls are the same color as the rest of the leaf blade, becoming brown as they mature. Infested leaves tend to be those under shady areas or where they are less exposed to sunlight. Heavily infested plants have malformed leaves that are noticeable at a distance.

The host plant is locally known as greasewood, an evergreen shrub of the Rosaceae family; it grows in the chaparral area in California. 

The galls induced by Phytoptus emarginatae are familiar and typically pouch type. They are scattered at random over the surface of the leaves. Each gall is elongate, clávate or fingerlike, of variable length, and erect or oblique. It protrudes through the upper surface of the blade; occasionally two galls are coalesced. Generally the galls are most conspicuous when yellowish and beginning to turn light brown. 

Phytoptus emarginatae appears to be widespread on several species of Prunus. It was first collected in galls on bitter cherry in California and subsequently in galls with Phytoptus prunidemissae on chokecherry in many areas of the Western United States. Other hosts include wild, common or European, wild-goose, and Sierra plums.

This is a striking and impressive pouchtype gall that appears on the upper surface of the leaf. Each gall is elongate, spindle shaped, about 4-8 mm long, with a pointed or attenuate tip, and is attached to the leaf blade by a slender stalk. The galls are solitary and tend to crowd, often particularly on the basal part of the leaf, mostly near the midrib. They vary from yellowish green to brownish, to reddish. The interior of the gall, where the mites are found, is hollow, with fleshy, turgid tissue. When mature, the galls split open longitudinally, dispersing the mites. 

Specimens have been found only on blackcherry in the Eastern United States. Phytoptus cerasicrumena is not likely to be confused with other species that infest Prunus. The galls induced by this mite are distinctive. 

The galls induced by this mite are easily distinguished by their position on the leaves. Either they occur on the lateral veins, or, when numerous, they are haphazardly scattered singly or in clusters on the upper surface of the leaf blade. The galls are small, variable in size, with hemispherical domes widely open on the underside. They range from yellow to yellowish tinged with red or pink, later becoming brown. The outer surface of the gall is covered with short, white hairs, and the interior is filled with erineum-like hairs, some of which project through the wide exit hole. A young leaf may have so many galls that its growth appears to be inhibited.

The host is buttonbush, a shrub that grows along streams and swamps in the Eastern and Western United States. Specimens were collected in Washington, D.C., and Florida.

The mite induces circular, shallow galls, 5-15 mm in diameter, outpocketed from the upper surface of the leaf blade. The underside is open and filled with firm, yellowish, irregular epidermal growth (see pi. 5, A). The mites live within the recesses of the growth or partly exposed to the surface, and when disturbed they remain motionless. The infestation seems particularly to affect the lower shaded branches of the tree.

The host is quaking aspen from California. Aculus dormitor (Keifer) is an inquiline in the gall.

Various willows are commonly infested by eriophyids. The situation is rather complex because the taxonomy of both the mites and the galls is uncertain. The galls on different willows are usually distinguished by form, color, position, density, and texture. Aculops tetanothrix belongs to a complex of gallforming eriophyid species that induce galls on different willows; consequently, the galls are varied. The galls caused by A. tetanothrix are 2-3 mm in diameter, beadlike, and irregularly rounded. They are often coalesced and scattered randomly or clustered alongside the midrib and in between lateral veins on the upper surface of the leaf blade. They vary from yellowish green to pinkish or reddish brown and purple. The exterior of the gall may appear roughened and shiny or covered with fuzzy fine hairs as on pussy willow leaves. Galls may be so numerous that they cover the entire leaf blade.

Eriophyes paramackiei

Hosts: Quercus agrifolia

A closely related species of E mackiei, Eriophyes paramackiei Keifer, also infests California live oak and causes a broom effect of densely clustered, stunted twigs on one side of the stem. The twiggy branches are stubby, with short, somewhat thickened branchlets, each crowded with numerous buds that contain mites. The tree infested with E. paramackiei shows the broom growths at the lower level of the tree, whereas the upper section does not look thrifty. 

The infestation caused by this mite results in the formation of peculiar galls involving the midrib and lateral veins of the upper surface of the leaves. The galls consist of pouchlike swellings arising from the leaf surface around the midrib and lateral veins, with the edges meeting over the veins to form "globular chambers." The galls coalesce and are covered with whitish hairs, which make them conspicuous and unmistakable. Galled leaves are considerably deformed.

Specimens were found in the galls on Sierra gooseberry in California and on coastal black gooseberry on Oreas Island, Wash., in September. Nearly every leaf of a plant was reported to be galled

The nail galls on linden leaves induced by Phytoptus tiliae are a familiar and striking foliage injury. They are usually numerous and are scattered at random over the leaf surface, generally missing the veins. Each gall is an elongate structure, attenuate distally, with a rounded or pointed tip, measuring 5-12 mm long, which may be erect, oblique, or curved, pro truding through the upper surface of the leaf blade. Some times two galls are coalesced at the base but form separate apices. The interior of the gall is filled with long, simple hairs near the base or opening (see pi. 6, D). The galls vary from greenish yellow to pinkish, to red and brown. They appear in June, maturing in July-August.

Although a common species, nothing is known of its life history. It is one of the many eriophyids that attack the linden family Tiliaceae and cause galls to form. Phytoptus tiliae is apparently widely distributed.

Eriophyes parulmi 

causes small, elongate, fingerlike galls that project from the upper surface of the leaf blade. They are randomly arranged, solitary, rarely coalesced and tend to crowd in the angles between the midrib and lateral veins. Specimens were found in July from Wisconsin westward.

Eriophyes ulmi

causes the formation of small, variable, bead like galls on the upper surface of leaves. Their exterior is rough, irregular and is covered with a few hairs like the rest of the leaf surface. They are the least impressive of the two galls. Specimens were collected in Canada and the Eastern United States on American elm and in England and Cyprus on elm.

T. batonrougei

The mites were found in berries that were characteristically deformed, shriveled, and dark ... 

For identity of those that infest juniper and cedar berries in North America, we suggest that specimens should be sent to specialists for proper determination. The characteristic symptoms of injury by [Trisetacus batonrougei, T. neoquadrisetus, and T. quadrisetus] appear similar to one another

[photos pg. 82]

Bud gall, stunted twigs, and defoliation caused by Eriophyes mangiferae (Sayed).

Infestation of the buds results in arrested growth, with the stunted, short, young stems close together at the terminal branch. When the leaves fall, the overall effect is scant growth of twiggy bunches, with a few stubby, short branchlets and discolored buds. Young trees are most seriously affected.

This species was discovered in Egypt on mango. It has been reported in Brazil, Mexico, India, Venezuela, and Florida. Eriophyes mangiferae was recently collected on galled inflorescences of mango trees in India. However, it is not known whether this mite causes the injury.

[Aceria] brachytarsus is similar to [Aceria] microcarpae Keifer, which causes similar pouch galls on little walnut (Juglans microcarpa Berland) and Arizona walnut (J. major (Torr.) A. Heller) in Texas, New Mexico, and Mexico.

The bud gall, known as big bud, consists of an aggregation of swollen, thickened scale leaves, often containing hundreds of mites. Their feeding activities suppress the developing young leaves or inflorescences enclosed within the scales. Eventually the enlarged buds become dark and reddish brown as they mature. The mite infests filbert or hazelnut in this country and in Europe.

[B]listers [first] appear as reddish or pinkish swellings, later as rough red swellings on the lower surface of the leaf blade. Often they coalesce, covering a large area of the leaf blade alongside the midrib.
As blisters become infested with mites, they turn dark brown to black, and by the end of the growing season the affected tissue has become dead and shrunken. Blisters ... not colonized by mites are pale green ... [B]listers without exit holes never contain mites.

.. oval or pear-shaped, greenish and whitish, unopened buds in a cluster of red flowers. Feeding activities of the mites abort the growth of flower buds, preventing the sepals and petals from opening, and the stamens, pistils, and other floral parts are distorted. 

[photos pg. 92]

causes irregular, wartlike, rough-looking galls on the upper surface of the leaves of seep willow [Baccharis glutinosa Pers.] and mule-fat [Baccharis salicifolia]


Trisetacus alborum at times causes the formation of clusters of stunted needles on ... pines ... Similar injury is caused on Douglas fir by T. pseudotsugae. The mites were found in Oregon infesting nursery seedlings, in which the growing tips form clusters of aborted needles. The infested seedlings are stunted and deformed.


Trisetacus sequoiae . . . colonizes and damages the buds, causing browning of the scales and some of the leaves behind the growing point and preventing further growth of lateral buds. As long as the buds or terminal shoots are infested, no new growth develops. [photos on page 99] 

Specimens were collected in buds of redwood during September along the northern California coast. 

The mites attack the buds and inhibit elongation of the shoot; the result is a visible configuration of the affected structure somewhat similar to a rosette. There is considerable crowding and bunching together of malformed, stunted, thickened shoots and aborted buds with short outgrowths.

Mite infestation of the flower buds inhibits elongation of the flowering stems and lateral branches. There is considerable distortion of the galled structure, which appears cauliflowerlike and of variable size or which forms clusters of aborted and contorted lateral branches, foliage, and flower heads. Since the flower stems fail to produce flowers, the reproductive capacity of the plant is greatly reduced. . . . Eriophyes chondrillae was introduced into California as a biological control agent. 

The redberry mite, Acalitus essigi, was found on Himalaya berry in California in 1921. It was subsequently reported on blackberry in California and Washington. It causes the well-known redberry disease, which forms an interesting and attractive contrast as a result of the mite feeding on the fruit between the drupelets and around the core. Infested berries show swollen, brilliant red or pink and greenish drupelets among unaffected purple or maroon drupelets. Some berries
have entirely red drupelets. Affected berries remain red or green and do not ripen normally. Often berries of late maturing varieties are seriously infested.


Acalitus vaccinii is one of the major pests of blueberry. This mite attacks the buds, which become succulent, fleshy, and closely packed in clusters or rosettes on the stem; they fail to expand and bloom. This results in the production of fewer berries and leaves, or bud loss. Affected berries appear roughened and malformed and may show small, reddish pimples or blisters. Infested plants in the field are easily recognized by the clustering or rosetting of the buds, which are sometimes abundant, and by marked discoloration of berries. . . 

It is present throughout the Eastern States and along the coastal areas from Canada to Florida and Texas. Keifer (1941) stated that this mite '"occurs on wild and
cultivated vacciniaceous plants, especially high bush types of Vaccinium spp." Acalitus vaccinii also infests huckleberry. 



[Host] Citrus spp. Grapefruit, Lemon, Lime, Orange, Other Citrus

Deformed buds, flowers, leaves, and fruit caused by
Eriophyes [now Aceria] sheldoni Ewing

The citrus bud mite['s] ... feeding within the buds invariably results in distortion of shoot growth, excessive and grotesque deformation of fruit, foliage, and blossoms, discoloration of fruit, and more commonly the production of numerous buds. The last may develop abortive twigs in tight clusters resembling witches'-broom and bunched terminal growth of distorted stems and leaves. Most malformed fruit drops prematurely. Mature lemon fruit shows blackened areas on the rind
beneath the sepals (buttons), where large colonies of mites are concealed. Deformed leaves and blossoms assume various shapes; the leaf blades are constricted at their middle, curled and twisted, and divided and divergent at the tips; and the blossoms are stunted and abnormal. The symptoms of injury on oranges are similar to those on lemons except fruit deformation is not so grotesque. Affected oranges usually develop to maturity, but they are commonly flattened, resembling the shape of tomatoes; or there are skin folds, seams and ridges, or small apertures in the stylar end. 

[Host:] Fraxinus sp. Ash
Inflorescence gall caused by Eriophyes fraxinivorus Nalepa

The infested inflorescence shows swollen and fused pedicels of individual flowers, often involving the peduncle or stalk. There is considerable distortion, and when the infestation is severe, every inflorescence is galled. Fully developed galls are conspicuously brownish, lumpy, and unsightly, usually remaining attached to the twigs from one season to the next. Galled inflorescences can be found throughout the year and are locally abundant ... European species

[photos p. 88]

Trisetacus gemmavitians ... causes a peculiar gall, which essentially is a conspicuous, beautiful rosette easily seen on pine trees. Each rosette consists of a cluster of aborted buds or stunted needles. Typically the shoots become infested, and the elongation of the growing point is inhibited. Numerous buds are clustered at the tip, and the needles that develop from these buds are stunted. When rosettes are numerous, the value of cut pine trees is greatly reduced. Infestations occur at the base of the needle beneath the sheath. The mites have been collected in the sheaths of stunted needles and in new buds. Trisetacus gemmavitians has been reported from Ohio and California. 
[pg. 90]


Trisetacus campnodus causes yellowing and stunting of Scotch pine needles. The mites colonize the needle base beneath the sheath. This area becomes necrotic and brown, at times calloused, and eventually the needles turn yellow and stunted, often distorted. Infested pine trees are chlorotic and generally appear unthrifty. This mite species was collected in Washington State.

[pg. 90]


Trisetacus alborum at times causes the formation of clusters of stunted needles on sugar and western white pines in California

The mites were found in berries that were characteristically deformed, shriveled, and dark ...

For identity of those that infest juniper and cedar berries in North America, we suggest that specimens should be sent to specialists for proper determination. The characteristic symptoms of injury by [Trisetacus batonrougei, T. neoquadrisetus, and T. quadrisetus] appear similar to one another

[photos pg. 82]

Trisetacus floridanus has been reported attacking terminal shoots and causing galls, aborted buds, and stunted needles on four species of pines in Florida: Sand, slash, and cedar pines and an unidentified pine species ... Rosette or clustering of numerous aborted buds and stunted needles is the typical injury [caused by genus Trisetacus mites.]

Leaves of butternut are often seen with large patches of 
erineum, similar in general appearance to that caused by 
Eriophyes erineus (Nalepa) on leaves of English walnut 
{Juglans regia L.). The erineum growths are conspicuous on 
the underside of the leaf blade, consisting of coalesced 
patches of dense felted hairs lying alongside the midrib, usu- 
ally filling the area between the lateral veins. On the upper 
side, the leaf blade with erineum patches appears swollen and 
puckered. The growth ranges from light brown to reddish 
brown.

[photo pg. 113]

The infestation caused by this mite is most noticeable as 
shiny, convex swellings on the upper surface of the leaf blade 
and on the underside as patches of shallow, large, solitary 
concavities lined with felty, yellowish hairs, among which the 
mites are to be found. These patches have well-defined edges 
and lie to the side of the midrib between the lateral veins; the 
erineum growths miss the small secondary veins and appear as 
thickened partitions. The erineum is particularly characteristic 
in that each structure is covered with short, minute, unicellu- 
lar hairs. Although erineum patches are fewer 
on the leaves, they are easily recognized because of their size 
and color.

[photo pg. 115]

 Colonization of 
a leaf by Eriophyes caliberberis results in considerable contor- 
tion; the leaf margin is curled upward, folded, and twisted 
across the upper surface toward the midrib. The leaf fold may 
involve the entire length of the leaf margin, with one or two 
windings forming a tube. The folded leaf eventually becomes 
crumpled and brown. The mite colonies are found in the tight 
leaf folds.

[photo pg. 143]

The mites are abundant in the folded terminal shoots, where their feeding apparently inhibits the expansion of the leaves. This results in the twisting of the folded terminal shoot and subsequent infolding, bending, and twisting of the leaf blade. Infested Bermuda grass may easily be recognized by the contorted terminal leaf blades ... This mite is not to be confused with Eriophyes cynodoniensis (Sayed), which also infests Bermuda grass but causes a rosettetype injury. 

[photos pg. 147]

Leaf roll caused by Eriophyes granati (Canestrini & Massalongo) (pl. 68) 

This is an interesting tubular leaf roll, which consists of a downward tight rolling and curling of the whole length of the leaf margin into a tube. Eventually the infested margin rolls toward the midrib but does not cover it. The mites are wrapped in the thickened turned-over leaf edge, where they live and reproduce inside the roll. In some plants, infestations are so heavy that nearly every young leaf is rolled, distorted, and twisted.

[photos pg. 151]

An Illustrated Guide to Plant Abnormalities Caused by Eriophyid Mites in North America