Carsia sororiata, the Manchester treble-bar, is a moth of the family Geometridae. The species was first described by Jacob Hübner in 1813. It is found in northern and central Europe, the Urals, Siberia, the Far East, northern Mongolia and in North America from Alaska to Newfoundland and to New Hampshire. Adults are on wing from July to August. The larvae feed on various Vaccinium species (including V. uliginosum, V. oxycoccos and V. myrtillus) as well as Rubus arcticus.