Aceria parapopuli (Keifer, 1940) (Eriophyes).

Mites overwinter in galls to exit in the spring and attack newly expanding vegetative and reproductive buds. Attacked buds form a woody, cauliflower-like gall that may exceed 3 cm in diameter (Fig. 19). Active galls normally persist for 1 year but can remain active for up to 15 years. New generations are produced every two to three weeks during summer months. Active galls are red and green, whereas dead galls are brown. Aceria parapopuli does not have a secondary host but can disperse between trees using wind currents (ref. on life history cited in McIntyre and Whitham 2003).

Primary hosts include P. angustifolia , P. balsamifera , and hybrid intermediates (Floate and Whitham 1993).

Aceria parapopuli

Eriophyes parapopuli

Hosts: Populus fremontii, nigra, tremuloides, angustifolia

Relationship: The mites cause irregular woody proliferation around buds, eventually hindering growth. In several years, the galls may be 1 inch or more in diameter.

Range: British Columbia, CA, CO, MT, OR, ND, NV, SD, UT, WY

Notes: This appears to be a complex of "cryptic" species (sibling species), adapted to each species and selected hybrids of cottonwoods.

Aceria populi [a distinct European species that may be present in the US but more likely represented by misIDs of parapopuli-complex mites]

Hosts: Populus tremula, italica, nigra, simonii

Relationship: Cauliflower Gall on Quaking Aspen; Bud galls on White Poplar;

Range: Ontario (probably an error); CO, ID, NY (error)

Notes: See records by Banks and Chadwick; but their records are probably in error. The first host listed was Populus tremula in 1889; that description was adequate for the code.

The record in NY was "Lebanon Springs, July 11, 1895, W. H. Harrison."

Eriophyes parapopuli Keifer

A fairly common gall on black cottonwood caused by eriophyoid mites, Eriophyes parapopuli Keifer, occurs at the base of buds along the stem. When branches are bare in the autumn, the galls are woody, brown, cauliflower-like, and rarely more than 2.5cm in diameter. Several occur along a single stem. The mites live in the cracks and fissures of the gall.

Eriophyes sp.

Irregular, granulated, woody bud enlargements, diameter 1.5 to 2.5 inches, mite

Eriophyes populi

Irregularly globose, tomentose bud masses, diameter .25 to .5 inch on Balm-of-Gilead, mite

?Eriophyes populi

Irregular masses of globose galls at base of leaf stem, mite

Eriophyes parapopuli
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Hosts: Populus tremuloides, balsamifera subsp trichocarpa, fremontii

The galls usually form on axillary and terminal buds and often involve large sections of stems.

Eriophyes sp
Cauliflower gall mite
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Hosts: Populus tremuloides, balsamifera subsp trichocarpa

When fresh in late spring or early summer, galls can be bright red and appear with numerous eruptions and fissures across the surface, but they turn dark brown with age.