Phytomyza tetrasticha


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.

Identification difficulty

Adult Leafmine

Recording advice

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.

When to see it

Leafmine: bivoltine - early Summer and late Summer.

Life History

It may pupate either in or outside the mine.

UK Status

Believed to be widespread in Britain but very poorly recorded.

VC55 Status

Status in Leicestershire and Rutland not known.

Leicestershire & Rutland Map


Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015

UK Map