A recent arrival and uncommon resident. Discovered in Buckingham Palace Gardens, London in 2014 (Ent Rec J Var 127:1, 2015), and subsequently in Kent in 2017, Middlesex in 2018 and further to a number of counties in south and eastern England. A miner of the undersides of narrow-leaved willow species are mentioned, as well as poplars. New for Hampshire in 2022, when mines were found on Salix fragilis in both spring and autumn in Blackwater on the Hants / Surrey border. It creates large, tentiform mines on the underside of leaves with a single sharp longitudinal fold. The adult is white or light ochre with brown markings; it is very similar to P. apparella requires genitalia determination for definitive identification.