A tiny, pale coloured moth with a wingspan of about 7 mm.  The larvae mine the leaves and twigs of smooth narrow-leaved willows, creating a silvery 'snail-trail' mine.  Phyllocnistis saligna and Phyllocnistis asiatica are part of a species complex, which is not yet fully resolved.

Adult Leafmine

The host should be identified where known; where mines are thought to be on Purple Willow the host must be explicitly confirmed. Photos/details should confirm the morphology of the mine (upper/lower or both surfaces, mine into petiole and stem or just in leaf, mine enters second leaf?). Early stage mines may be inconclusive.

Where smooth-leaved willows are present.

Adult moths are at large in two generations, in July and from September through to April. The overwintering adults are sometimes found in thatch or haystacks. Larval mines are best looked for in June, or in August/September.

The larva mines the leaves of various smooth-leaved Willows, causing a thin silvery mine like a snail-trail in the upper epidermis of the leaf, and continuing down the twig to mine another leaf. Pupation is under a leaf-fold at the edge of a leaf. 

P. saligna has been shown to be a complex of several species, and it is likely that most (all?) VC55 records are actually referable to P. asiatica. The status of both species is under review, via both host species and mine morphology, along with DNA analysis. In the meantime, where no dissection of an adult female has been completed, records should be entered as P. saligna/asiatica agg.

Common as a species complex in Leicestershire and Rutland, and increasingly well recorded from the leafmines on smooth-leaved willows such as Crack-willow, White Willow and Weeping Willow.

Phyllocnistis saligna is in fact a complex of four species, recently discovered by DNA analysis.  P. asiatica is the species recorded on White Willow and Crack Willow.  P saligna is the species recorded on Purple Willow.  VC55 records where the host species is not known are likely to be P. asiatica.  See Edmunds, R. & Plant, C. (2023) Phyllocnistis saligna (Zeller, 1839) (Lep.: Phyllocnistinae) is a complex of species. Which of these occur in the UK?.  British Leafminers 43 1-2.  http://www.leafmines.co.uk/pdfs/newsletter%2043.pdf:

http://www.leafmines.co.uk/html/Lepidoptera/P.saligna.htm

https://bladmineerders.nl/parasites/animalia/arthropoda/insecta/lepidoptera/ditrysia/gracillarioidea/gracillariidae/phyllocnistinae/phyllocnistis/phyllocnistis-saligna/