Stem miner (Diptera: Agromyzidae) in Alliaria

On 23 June 2022 I collected a mature garlic mustard plant with a short, whitish, linear stem mine in the upper half of the stem. I examined the mine closely and found it to contain a very young gracillariid larva (see record 0035), but I observed no other larvae. I held the stem in a rearing container until 20 July, when a female Ophiomyia sp. agromyzid emerged. Examination of the stem revealed the fly's puparium formed just under the epidermis, surrounded by extensive stem mining with a pattern of alternating strips of frass. The gracillariid larva was nowhere to be found and the whitish linear mine containing it had long since been obliterated by the fly's mining. Blossey et al. (2001) mention a stem-mining fly they found associated with garlic mustard in North America, but the fly's taxonomic family was not reported and the authors' definition of stem mining was not specified, so it is unclear whether the insect they found might be the same as this one.