The larvae of the fly Phytomyza tetrasticha mine the leaves of mint, especially Water Mint. The mine starts with a small spiral and then develops into a greenish blotch (frequently on the leaf margin), which turns brown as it ages. The pupa is yellow-brown in the summer generation and deep black in the winter one.
Adult: Unless identified by a recognised expert, a photo is required and the specimen should be examined with a microscope. In the comments box, state the key or ID method used and describe the size and identifying characters.
Leafmine: Unless identified by a recognised expert, a photo is required. If the photo doesn't show the key ID features then in the comments box describe the size and identifying characters you have observed.
Wherever the larval foodplants occur.
Leafmine: bivoltine - early Summer and late Summer.
It may pupate either in or outside the mine.
Believed to be widespread in Britain but very poorly recorded.
Status in Leicestershire and Rutland not known.
Leicestershire & Rutland Map
Enter a town or village to see local records
Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015