About Psyllopsis fraxini (Linnaeus, 1758)
Psyllopsis fraxini (Linnaeus, 1758) is a psyllid that lives inside a gall formed on Fraxinus excelsior, common ash. Females lay eggs in autumn on the species' dormant buds. Nymphs hatch the following spring and begin feeding on ash leaves. The host ash plant responds to the nymphs' activity by growing extra cells; the affected leaf tissue swells, rolls downward, and forms a gall that encloses the wax-covered nymphs. A single gall can house two or three generations of Psyllopsis fraxini, and by the end of summer, all life stages of the insect can be found inside the gall. Galls formed by this species are pale in overall colour, with violet or red markings.
