This species has two generations a year that induce distinct bud galls on different Solidago species. The early-spring generation was found only on S. altissima in April–May ... they developed in buds that grew from the rhizomes and were barely visible above ground... Galled buds were wider and felt harder to the touch than normal buds, were 5 cm long and 2 cm wide, and contained a single chamber, the internal walls of which were lined by a thick layer of white mycelium... In May, some galls were found in much longer sprouts (∼15 cm long) that still appeared stunted and somewhat thicker than normal sprouts.
[this species was thoroughly researched and re-described by the authors of this paper; please refer to it for many more details of gall biology, insect life history, anatomy, and phylogeny]
”- Netta Dorchin, Jeffrey B. Joy, Lukas K. Hilke, Michael J. Wise, Warren G. Abrahamson: (2015) Taxonomy and phylogeny of the Asphondylia species (Diptera: Cecidomyiidae) of North American goldenrods: challenging morphology, complex host associations, and cryptic speciation©