This species is bivoltine and induces morphologically different bud galls in spring (April–May) and summer (August–September), which are very similar on all three host plants. ... White chambers that are similar to those in the spring galls appear in the gall around mid July ... and each chamber contains a single larva that is found deep in the chamber, facing downwards. Each chamber is surrounded by a group of very short and narrow leaves, which in turn are surrounded by longer and wider leaves to form a distinct subunit within the gall. Usually at least 2–5 subunits are clumped together at the shoot apex to form a conspicuous rosette that is 3–5 cm in diameter. ... The rosette gall of R. capitata ... is superficially similar but does not contain distinct subunits and appears flatter than galls of R. solidaginis.

- Netta Dorchin, Miles V. McEvoy, Todd A. Dowling, Warren G. Abrahamson, Joseph G. Moore: (2009) Revision of the goldenrod-galling Rhopalomyia species (Diptera: Cecidomyiidae) in North America^©