Twenty-two alfalfa clones were evaluated for potato leafhopper,Empoasca fabae(Harris), resistance by infesting excised plant parts with adult leafhoppers in a controlled environment. Field ratings for yellowing and laboratory ratings for yellowing and wilting correlated significantly. Leafhopper yellowing in the field and nymphs/gram of dry plant material did not correlate. Clonal preferences were displayed in both the field and laboratory, but the ratings did not correlate.Excised parts from plants in the field provided a more reliable assessment of resistance than did similar parts from plants growing in a greenhouse. Clonal yellowing and wilting of excised terminals from field grown plants were correlated highly (r=0.91**) with yellowing in the field. Excised stem terminals from plants growing in a green-house were less resistant to both adult and nymphal leafhopper feeding than were terminals from plants grown in the field.