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).

- Kevin Floate: (2010) Gall-inducing aphids and mites associated with the hybrid complex of cottonwoods, Populus spp. (Salicaceae), on Canada’s grasslands^©