Potato leafhoppers attack many landscape trees, such as maple, crab apple, birch, and ash. Red maples are most susceptible; silver, sugar, and Norway maples are more tolerant. Potato leafhoppers possess piercing–sucking mouthparts that they use to feed in the vascular tissues of plants. As they feed, they inject a toxic fluid into plant tissue. Feeding, especially on maples, causes stunted tree shoots and leaves that curl downward with brown edges. On other plants, such as ash, potato leafhopper feeding creates small white or yellow spots on leaves, resulting in a stippled appearance because potato leafhoppers remove the chlorophyll (green pigment) from the leaves. Potato leafhoppers don’t overwinter in Illinois because their eggs are very sensitive to cold temperatures. They winter in the Gulf of Mexico and are blown north into Illinois by prevailing winds from around early May to early June.
Potato leafhopper adults settle into alfalfa fields during the early spring migration; they may then migrate onto ornamental plants during the first cutting of alfalfa. Adults are small (approximately 1/16 inch long), wedge shaped, and pale green with white eyes. Females lay eggs into the veins on the underside of leaves. Eggs hatch in six to nine days into light green nymphs that are found on leaf undersides and tend to move sideways when disturbed. Nymphs may undergo five instars before molting into adults. Adults and nymphs are similar, except that adults are larger, have wings, and can fly. The wings are held rooflike over the body. Empty white cast skins on the underside of leaves provide evidence of potato leafhopper activity. There are three to five generations per year.
Insecticides must be applied before potato leafhoppers cause plant damage. Control can be obtained with the use of pyrethroid insecticides such as bifenthrin (Talstar), cyfluthrin (Tempo), lambda-cyhalothrin (Scimitar), and permethrin (Astro). If damage has already occurred, insecticide applications will prevent further damage, and new growth will appear normal above the damaged leaves. Regular scouting helps minimize the potential for potato leafhoppers to cause severe foliar damage.