Agromyza alnibetulae

The larva produce a leaf mine in the leaves of Birch. The mine is an unusually long, upper-surface corridor that widens only little and winds freely through the leaf. Frass in two neat rows.

See the National Agromyzidae Recording Scheme website for further details of the mine, larva and adult insect

ref.: Warrington, B.P. (2023).  Agromyza alnibetulae. Accessed at https://agromyzidae.co.uk/species/agromyzidae/agromyzinae/agromyza/agromyza-alnibetulae-hendel-1931/ on 13/12/2023)

The mines of Stigmella micro moths are similar, but only have a single frass line, or dispersed/coiled frass.

Leaf-mine Adult

Provide backlit photographs of the whole leaf-mine in the leaf, and the larva, and note the host plant. 

On the leaves of Birch species

Click on the 'further details' link in the 'Description' section above.  Then click on the Phenology tab which will provide phenology details for both adult and larval stages.

Local

Warrington, B. P. 2022. A provisional review of the status of Agromyzidae in Great Britain & Northern Ireland

Occasional in Leicestershire and Rutland, mainly from the west of the area where Birch is more frequent.

http://www.leafmines.co.uk/html/Diptera/A.alnibetulae.htm

https://bladmineerders.nl/parasites/animalia/arthropoda/insecta/diptera/brachycera/agromyzidae/agromyzinae/agromyza/agromyza-alnibetulae/