The potato leafhopper migrates north in the spring, arriving before potatoes emerge. Leafhoppers develop in alfalfa first, moving to potatoes later. The nymphs resemble the adults but are wingless. When disturbed, the nymphs move across the leaf in a sideways fashion. Damage by leafhoppers is referred to as hopper-burn.
Foliage becomes dwarfed, crinkled, and curled.
Small triangular brown areas appear at the tips of leaves, gradually spreading around the entire leaf margin. Immature leafhoppers are more destructive than the adults, and generally more numerous than adults. Treatments are recommended when potato leafhoppers can be found at a level of 1 nymph per 10 leaves. Sample 35 leaves in each of 5 locations in a field. Pluck leaves from the plants and inspect the underside of the leaf for the presence of the nymphs.