Wingspan 7 to 9 mm. A variable species, some specimens appearing very dark and some much paler. There is a broad whitish basal streak which is usually quite obvious. The larva mines the leaves of several species of Alder, creating an oval tentiform mine with a sharp crease on the under-surface.  The larva is greenish, and pupates in a frass-encrusted cocoon inside the mine.  This is visible as two dark lines either side of pupa.

Several other Phyllonorycter mine Alder leaves, and if the under-surface crease is not fully developed it can look similar to P klemannella.  If in doubt, check pupa (ref. Bladmineerders.nl)

Adult Leafmine

Photograph the underside of the mature mine

Areas where the larval foodplant is present.

Adults fly in two generations; in May and again in August.

The larvae feed on Alder including Italian Alder

It is quite a common species throughout the British Isles. In the Butterfly Conservation’s Microlepidoptera Report 2011 this species was classified as common.

Occasional in Leicestershire and Rutland. L&R Moth Group status = C (very scarce resident or rare migrant).

http://www.leafmines.co.uk/html/Lepidoptera/P.rajella4.htm

https://bladmineerders.nl/parasites/animalia/arthropoda/insecta/lepidoptera/ditrysia/gracillarioidea/gracillariidae/lithocolletinae/phyllonorycter/phyllonorycter-rajella/