GALL
The topmost 2-4 internodes are completely shortened, their leaf sheaths are thickened. The solitary, white, larva lies between the leaf sheaths above the vegetation point. (This is contrary to L. lucens and rufitarsis, where the larva has bored itself down through the growing point to live in the very tip of the stem). The maximal thickness of the gall is less than twice the thickness of the stem just below.

HOSTPLANTS
Poaceae, monophagous: Phragmites australis

- Willem N. Ellis: (2021) Plant Parasites of Europe^©

Reference: https://bladmineerders.nl/parasites/animalia/arthropoda/insecta/diptera/brachycera/chloropidae/oscinellinae/lipara/lipara-pullitarsis/