Description and life cycle
Nymphs and adults of the potato leafhopper are yellowish green to pale green and otherwise resemble white apple leafhoppers. Nymphs tend to move sideways and quickly retreat to the opposite side of the leaf when disturbed.
Potato leafhoppers overwinter as adults in southern states and move northward mainly through the action of storm fronts. They arrive in southern Pennsylvania in late May or early June. Their movement and severity depend on many weather-related phenomena as well as the availability and proximity of alternate food sources. Therefore, the seriousness of this pest is sporadic. It is most damaging from mid-June to mid-August.
Unlike the white apple leafhopper, the potato leafhopper feeds near the edges of leaves. A triangular chlorotic area extends from the feeding site to the leaf edge. If several feeding sites are present on a leaf, the leaf will cup downward. If several leaves on a shoot are affected, shoot growth may be greatly stunted. Feeding by the potato leafhopper in the vascular tissue is such that it may spread fire blight.
Monitoring and management
Scout often after mid-May following frontal systems. No threshold is currently available. Fire blight susceptible varieties and young trees where this species has been a problem in the past should be protected when the first adults appear. Specific chemical recommendations for home gardeners are in Fruit Production for the Home Gardener, and recommendations for commercial growers are in the Penn State Tree Fruit Production Guide.