Blackened, carbonaceous tissue on leaves of Grindelia.

Asteromyia ... grindeliae.
USA (California, Minnesota, Texas, Maryland). Grindelia robusta; Grindelia spp. (Asteraceae).

[In this article Gagné assigns Asteromyia galls on Grindelia to A. modesta, reducing Felt's A. grindeliae to synonymy. However, several decades later, his checklist with Mathias Jaschhof (2021) resurrects A. grindeliae. In 1968 he listed the following additional Grindelia species as possible Asteromyia hosts based on observations of galls only (no insect material available). These host records are assigned to this gallformers page tentatively, but could alternatively indicate host-range extensions of other species, or additional undescribed species:
Grindelia nana [G. hirsutula], G. microcephala, G. lanceolata]

Asteromyia grindeliae

Grindelia

Blister leaf gall, greenish or blackish, diameter 1/8 inch, summer