Eriophorum angustifolium
The larvae feed on glaucous sedge ("Carex flacca"), carnation sedge ("Carex panicea"), black sedge ("Carex nigra"), common spike-rush ("Eleocharis palustris") and common cottongrass ("Eriophorum angustifolium"). The larvae form an upper-surface mine, starting just under the tip of the leaf. They first form a corridor which runs upwards, then doubles, widening all the while, with the final part taking about half the width of the leaf. There is some confusion as to the form of the mine with a different description on the UKmoths website.