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Potato Leafhopper

July 3, 2006
Be on the lookout for damage caused by potato leafhopper, Empoasca fabae, on ornamental landscape trees such a crabapple (Malus spp.), birch (Betula spp.), ash (Fraxinus spp.), and maple (Acer spp.). Red maples, in particular, are extremely susceptible to potato leafhopper feeding, whereas silver, sugar, and Norway maples are more tolerant.

Potato leafhoppers, both adults and nymphs, have piercing–sucking mouthparts, which they use to feed within the vascular tissues of plants—primarily the xylem. During the feeding process, potato leafhoppers inject a toxic substance into plant tissues. Feeding, especially on maples, results in stunted shoots and leaves that curl downward, with brown edges. This damage makes infested trees appear as though they have been sprayed with a phenoxy-based herbicide such as 2,4-D. On ash trees, feeding by potato leafhopper adults and nymphs creates small white or yellow spots on leaves, which results in a stippled appearance that closely resembles twospotted spider mite (Tetranychus urticae) feeding injury. Similar to twospotted spider mite, potato leafhoppers remove chlorophyll (green pigment) from leaves. Potato leafhoppers do not overwinter in Illinois because the eggs are sensitive to the cold temperatures. Adults are blown north, from the Gulf of Mexico, into Illinois by prevailing winds from early May through June.

Potato leafhopper adults settle into alfalfa fields during the spring migration; and after the first cutting of alfalfa, they migrate onto ornamental landscape trees. The adults are about 1/16 inch long, wedge-shaped, and pale green in color, with distinctive white eyes. Females lay eggs in the veins on the underside of leaves. Eggs hatch, within 9 days, into light green nymphs that are typically found on leaf undersides and tend to move sideways when disturbed. Nymphs undergo five instars before molting into adults. Adults and nymphs look very similar except that adults are larger and possess wings, which enables them to fly. The wings are held rooflike over the body. Potato leafhopper activity may be assessed by the presence of empty white cast-skins located on the underside of leaves. There may be up to five generations per year in Illinois.

Insecticides must be applied to susceptible trees before potato leafhoppers cause severe plant damage. Insecticides recommended for controlling potato leafhoppers include the pyrethroid-based products bifenthrin (Talstar), cyfluthrin (Tempo), lambda-cyhalothrin (Scimitar), and permethrin (Astro). If plant damage has already occurred, then insecticide applications will prevent further damage, and any new growth will appear normal beyond the damaged leaves. It is important to regularly scout susceptible trees to minimize the potential for potato leafhoppers’ causing severe foliar damage, which can ruin the aesthetic appearance of ornamental landscape trees.