Resistance of Alfalfa Cultivars to the Threecornered Alfalfa Hopper (Homoptera: Membracidae)

Alfalfa, Medicago sativa L., cultivars were evaluated under field conditions for resistance to the three cornered alfalfa hopper, Spissistilus festinus (Say). Resistance was characterized by monitoring adult populations and girdle damage. Tolerance and adaptability to Louisiana growing conditions were characterized by monitoring stand persistence. ‘GA Plains’, ‘Zia’, ‘Condor’, ‘Florida 77’, and ‘Cuf 101’ exhibited resistance to the three cornered alfalfa hopper by having reduced girdle damage in comparison with the other cultivars. ‘Ladak’ showed the highest level of susceptibility in terms of girdle damage and is recommended for use as a susceptible check. ‘Cimarron VR’, ‘GA Plains’, and ‘WL 516’ showed the lowest percentage of plants lost. Cultivar ranks varied by location and date, indicating multiple counts and locations must be used to categorize alfalfa resistance adequately.