Colomerus vitis

Phytoptus vitis

Hosts: Vitis vinifera, aestivalis, vulpina. There are probably different species of Colomerus on native wild grapes

Relationship: Erineum on leaf undersurfaces.

Range: California, Florida, Maine, Ohio, Oregon, New York, Washington USA

Eriophyes vitis [Felt also lists many other erineum-forming mites on Vitis species, referring to Chadwick '08. None of these appear in the Amrine catalog except with the implication they might exist.]

Vitis
Leaf or tendril galls
An erineum on the under side of the leaf, causing a swelling above, on Vitis vinifera

Eriophyes vitis Landois

In central Europe, Italy and in California the leaves of the vine are often deformed by attacks of a minute mite. In in- fested leaves the portions between the larger veins puff up, leaving a cavity on the under side which is clothed with a dense felt-like covering. As a rule, thin-leaved varieties of grape are more subject to attack, or at least show greater evidence of the presence of the mite. In California erinose rarely causes serious injury to the vine or to the crop; it has often been confused with a fungous disease, the powdery mildew.

The mite, as usually found on the leaf, is a minute, nearly colorless, elongate, four-legged creature, about .13 mm. in length. The mites hibernate under loose strips of bark on the larger branches of the vine and in the spring migrate to the under side of the opening leaves where they puncture the epidermal cells with their sharp mandibles, thus producing abnormal thread-like outgrowths from the underlying layers of cells, known as erinea. These erinea when abundant have the appearance of dense felt, and it is in the shelter thus afforded that the mites live, lay their eggs and the young find suitable food. From time to time individuals leave the older leaves and start new colonies on the young leaves at the ends of the branches. In the fall some of the mites desert the leaves and go into hibernation on the bark of the older canes.

Colomerus vitis

Only two of the three strains of this mite caused symptoms on Spanish wild vines, the erineum and the leaf curl strains (OCETE et al. 2000), but all of them chose buds for hibernation. The presence of felty galls (erinea) on the lower leaf surface and blisterlike swellings on the upper one, caused by the first cited strain, are much more frequent than downward curling or rolling leaves, caused by the other cited strain.

Eriophyes vitis Land.

Vitis
Leaf or Tendril Galls
Leaf pile on under surface of V vinifera, mite, summer

Eriophyes sp.

Vitis
Leaf or Tendril Galls
Warty or pouch leaf galls or brownish or whitish leaf pile, mite, summer

Colomerus vitis

Colomerus vitis (Acari: Trombidiformes: Eriophyidae) includes bud, leaf curl, and leaf blister eriophyoid mites that cause significant economic damage to grapevines worldwide. It has been hypothesised that different genetic or morphological strains of C. vitis cause the three different plant symptoms. [. . . ] Bud and blister mites were significantly associated with different genetic groups. [. . . ] In conclusion, these results indicate that “C. vitis” includes several genetic groups of sufficient diversity to justify the proposal of separate species, rather than strains of a single species each associated with different plant symptoms. These putative species occur in mixed populations within the different plant symptoms, and do not appear to be morphologically unique enough to allow morphological separation of all five species detected here.

The leaf blister (erineum) mite strain (Figure 1.2 B, C) feeds on the underside of the leaves leading to gall formation on the top surface of the leaves (Smith Meyer, 1981). Damaged leaf cells multiply and form fine white or yellow hairs, causing felt-like patches called trichomogenic erinea on the under surface of infested leaves (Slepyan, 1969). Patches form in 10 to 30 days from when the mites first start feeding, depending on the leaf development rate. The patches initially appear white, then turn yellow and finally reddishbrown. Patches arise mainly on the apical leaf part, above the upper parts of the incisions. Leaf erinea decrease the photosynthesis ability of the leaf, but usually not to a physiologically damaging point. Thus, the leaf blister strain of C. vitis is usually not considered a serious economic pest.

Females of the leaf blister strain overwinters under outer scales of dormant buds (Duso and DeLillo, 1996; Smith Meyer, 1981) and sometimes under bark crevices (Duso and De Lillo, 1996). The females start moving to unfolding leaves as the bud swells in spring, where they start inducing erinea and reproducing (Duso and DeLillo, 1996; Smith Meyer, 1981). Development mostly occurs in the erinea. The first generation requires approximately 25 days, but the subsequent six generations in the season can develop much faster (Mathez, 1965). In late spring and early summer, the mites migrate to apical leaves and induce new erinea. In late summer and the beginning of autumn, the females start migrating to their overwintering sites in the buds. Since these mites are very sensitive to desiccation, they only migrate in the evening to survive (Smith Meyer, 1981).