University of Illinois

No. 16/July 10, 1997

Potato-Leafhopper-Resistant Alfalfa

A lot of folks are talking about the varieties of alfalfa that are resistant to potato leafhoppers. Several seed companies are selling this alfalfa, and many of us are curious about how it holds up in the fields this year, particularly if densities of potato leafhoppers are large, as they are in some areas of the state right now.

To help us stay abreast with the performance of potato-leafhopper-resistant alfalfa, Dave Feltes and Jim Morrison, Extension educators in IPM and crop systems at the Quad Cities and Freeport Extension centers, respectively, are monitoring leafhopper densities in a strip trial in northwestern Illinois. They will be counting adults and nymphs and assigning an injury rating to at least six different plots throughout the summer. At least one of the varieties is susceptible. The comparisons should be interesting. I would imagine that counts of adults may not be different among the plots (nothing in the resistant varieties repels leafhopper adults). However, counts of nymphs and injury ratings should be quite low in the leafhopper-resistant plots if the varieties hold up. We'll provide information as it is gathered to keep you informed.
Kevin Steffey, Extension Entomology, (217)333-6652