The psyllid causes galls to form on the shoot tips of Box. The galls take the form of pale, cabbage like clusters, the bunched leaves being strongly concave and slightly thickened.  During the summer they conceal numerous tiny pale green nymphs covered with white wax. The adult psyllids are green with an orange tip to the abdomen, and have a dark collar; the wings are yellowish and unmarked. 

Spanioneura fonscolombii is also present on Box, but does not cause galls; the forewings are marked with 4 black dots at the apices of the cells

Gall Adult/Nymph

Photograph the gall on the host plant. If recording the adult or nymph, state host plant and provide good quality photographs

Where Box, the host plant, is present.

Adults mature in late summer and lay overwintering eggs

Widespread in the UK, and locally common (ref.: British Bugs website; link below)

Frequent on host plant

https://www.britishbugs.org.uk/homoptera/Psylloidea/Psylla_buxi.html

https://bladmineerders.nl/parasites/animalia/arthropoda/insecta/hemiptera/sternorrhyncha/psylloidea/psyllidae/psyllinae/psylla/psylla-buxi/