Elachistidae

38.042 Dusky Sedge-miner Elachista serricornis (Stainton, 1854)

Notable A

Similar species:

Forewing: 3 to 4.5mm

Habitats: Damp shady woods and boggy areas.

Habits:

Foodplant: The larva mines a leaf of Wood-sedge or Common Cottongrass. In late autumn when Wood-sedge is the host, it mines a long, narrow, red-brown gallery where it overwinters. In spring a new mine is formed at the base of a fresh leaf. It widens as it ascends until it finally opens into a long yellowish blotch composed of several parallel galleries with the frass scattered in separate patches. When Common Cottongrass is the host, it mines a stem near the base of the plant and sometimes feeds between the leaf sheath and the stem. The grey-green larva has a whitish dorsal line. The head is light brown. The prothoracic plate is also light brown with darker marks on each side connected with a whitish streak. Pupation takes place on the leaf litter at the base of the plant.

On the European mainland it has also been recorded feeding on Rare Spring-sedge, Bladder-sedge, Rusty Sedge, Tufted-sedge, Common Cottongrass, Broad-leaved Cottongrass, Hare's-tail Cottongrass and Wood Club-rush.