Oklahoma State University Stillwater, OK
Oklahoma Alfalfa Oklahoma Cooperative Extension Service Oklahoma Agricultural Experiment Station

POTATO LEAFHOPPER IN ALFALFA The potato leafhopper does not overwinter in Oklahoma, but migrates northward from the Gulf Coast and is usually first collected in alfalfa during April. Damaging populations are most common from June through August. Alfalfa that has been heavily infested by potato leafhoppers shows a characteristic yellowing or chlorosis in a V-shaped pattern at the tips of leaves. This symptom is called tip-burn or "hopperburn". Although the chlorosis may be accompanied by some leaf drop and reduction in quality of forage, a more serious problem is stunting of plant growth and significant yield loss.      By the time "hopperburn" becomes obvious, serious yield reduction may already have occurred due to feeding by leafhoppers. Thus, sampling for leafhoppers should be done in early stages of regrowth after the second and each subsequent harvest. Sampling is done with a sweepnet by taking at least 100 sweeps (5 groups of 20 sweeps each) per field when regrowth is 4-6" tall. When alfalfa is <6" tall, insecticide should be applied if numbers of leafhoppers exceed 10 per 20 sweeps (0.5 per sweep). Additional information on insecticides registered for control of leafhoppers can be found in OSU Extension Facts #7150.

Richard Berberet, Alfalfa Entomologist  Department of Entomology and Plant Pathology  Oklahoma State University

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