Eggs hatch in six to 10 days. Psyllid nymphs feeding on potato leaf. Newly hatched nymphs are yellowish but become progressively greener as they develop, undergoing four molts. When almost mature, nymphs are nearly the same color as leaves. Nymphs are flat, elliptical and scale-like.
Nymphs are most numerous on the undersides of leaves but can occur on shaded upper leaf surfaces.
They are inactive and seldom can be seen to move about. This material may cover leaves during heavy psyllid infestations. The nymph stage usually lasts from 14 to 22 days. Newly emerged adults remain green for a day or so before turning darker. Problems with psyllids originate each season from winged, migrating forms of the insect.