Potato Leafhopper in Alfalfa
Crop Injury: Potato leafhopper (Empoasca fabae) adults and nymphs can cause severe injury to alfalfa plants by sucking sap from foliage. A condition known as “hopperburn” can develop as leaves begin to yellow at the tips and eventually look as if burned. Leaf distortion and crinkling, along with plant stunting, can occur. Continued injury can reduce winter survival and yield potential of future harvests. Feeding reduces alfalfa quantity and quality.
Pest Description: Potato leafhoppers are very small and pale green, with large white eyes. They are wedge-shaped and fly quickly when disturbed. Nymphs lack fully developed wings and are smaller and lighter green than adults.
Potato leafhopper adult.
Daren Mueller
"Hopperburn" on alfalfa from potato leafhopper feeding.
Deborah Samac
Life Cycle: Leafhoppers migrate to northern areas from overwintering sites in warmer southern regions. Eggs are laid in alfalfa stems and leaf midribs. Eggs hatch and nymphs begin feeding, developing through five instars before reaching adulthood. Multiple generations can occur per year and populations are capable of rapidly increasing.
Potato leafhopper life cycle in alfalfa.
Mimi Broeske, Nutrient and Pest Management Program, University of Madison-Wisconsin
Scouting: Start scouting on a weekly basis after the first harvest. Use a sweep net to determine presence and number of leafhoppers. Drought conditions can worsen leafhopper injury symptoms. Leafhopper injury may appear similar to herbicide damage, nutrient imbalances, and drought stress.
Management: The best way to manage potato leafhopper in alfalfa is to plant insect-resistant alfalfa varieties and use informed insecticide application. Glandular-haired varieties can reduce losses; be aware that some “resistant” varieties still experience yield losses but lack symptom development. Scouting and thresholds for insecticide application can differ by state. Thresholds depend on leafhopper number and plant height; check with local extension resources for the most up-to-date information. Early harvest can help to avoid high leafhopper populations; late harvest can allow injured plants to recover somewhat.
Using a Sweep Net in Alfalfa
Prepared and reviewed by the Alfalfa Pest Management Working Group.
Potato leafhopper adult.
Potato leafhopper burn on alfalfa plants.
Potato leafhopper burn on alfalfa plants.
Potato leafhopper nymph.
Potato leafhopper burn on susceptible alfalfa plants (left), compared to resistant plants on the right..
Gallery images courtesy Daren Mueller, Deborah Samac, and Adam Sisson.
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