Potato leafhopper, Empoasca fabae, is starting to be found in portions of Illinois. Potato leafhoppers attack many landscape trees, including maple, crabapple, birch, and ash. Red maples are extremely susceptible, whereas silver, sugar, and Norway maples are more tolerant.
Potato leafhoppers have piercing–sucking mouthparts, with which they feed within the vascular tissues of plants. During feeding, they inject a toxic fluid into plant tissue. Feeding, especially on maples, results in stunted tree shoots and leaves that curl downward, with brown edges. On other plants, such as ash, feeding by potato leafhoppers creates small white or yellow spots on leaves, resulting in a stippled appearance because potato leafhoppers, like spider mites, remove the chlorophyll (green pigment) from leaves. Potato leafhoppers don’t overwinter in Illinois because their eggs are very sensitive to cold temperatures. So how do they get into Illinois? They winter in the Gulf of Mexico and are blown north into Illinois by prevailing winds from early May to early June.
Potato leafhopper adults settle into alfalfa fields during the early spring migration, and then after the first cutting of alfalfa they migrate onto ornamental plants. Adults are small (about 1/16 inch long), wedge-shaped, and pale green, with white eyes. Females lay eggs into the veins on the underside of leaves. The eggs hatch in 6 to 9 days into light green nymphs that are found on the underside of leaves 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 pyrethroid-class insecticides, such as bifenthrin (Talstar), cyfluthrin (Tempo), lambda-cyhalothrin (Scimitar), and permethrin (Astro). If damage has already occurred, insecticide applications prevent further damage, and new growth appears normal beyond the damaged leaves. Regular scouting helps minimize the potential for potato leafhoppers to cause severe foliar damage.