Potato leafhopper (Empoasca fabae) is a major pest of alfalfa and other legume forage crops. In Pennsylvania, it causes over $15 million in average losses annually. It reduces yields, quality (especially lower protein content), and stand longevity. The stress leafhoppers trigger has increased root rot and stand failures. This damage is especially evident in new seedings.
Leafhopper nymphs and adults feed on the undersides of the leaves. By extracting the sap, they cause stunting and leaf curl, as well as a yellowing of leaf tissue known as “hopper burn.” This discoloration is caused by injection of a toxic substance into the leaf tissue. “Hopper burn” is characterized by a yellowing of the tissue at the tip and around the leaf margin which continues to increase until the leaf dies. Many times this can be confused with drought stress.
Leafhoppers overwinter in the southern Gulf states and migrate north in the spring. After mating, eggs are laid inside the veins on the underside of leaves. A female leafhopper lives about a month, producing only 6 eggs a day. Eggs hatch in about 10 days, nymphs mature in about 2 weeks, and begin feeding on leaf tissue. Mating occurs about 48 hours after maturation. As many as 3-4 generations can be produced in one year.
For more information on when and how to sample your forage stand for potato leafhoppers and how to determine your economic injury threshold, visit Penn State’s Entomology website.
Options for control of potato leafhopper available in today’s market are insecticides and recently, new varieties of leafhopper-resistant alfalfa. To read more about chemical control options, you can consult this University of Delware publication or the Penn State Agronomy Guide.