Galls are most obvious in August and September, when young leaves at the top of a shoot, above the summer growth are hairy, crinkled and have depressions containing a flat
psyllid nymph. Heavilly infested leaves are stunted and much darker than the unaffected leaves. There are two or three generations a year and psyllid populations are at their peak in the autumn; hence when the galls are easily seen. The autumn generation overwinters in turf or evergreens. Host plants include common nettle (
Urtica dioica), small nettle (
Urtica urens) and
Urtica membranacea. ==Distribution==