EFFECTS OF NYMPHAL POPULATIONS OF 3-CORNERED ALFALFA HOPPER (HOMOPTERA, MEMBRACIDAE) ON FLORIDA-77 ALFALFA PLANTS

High (six nymphs per plant) and moderate (three nymphs per plant) infestations of threecornered alfalfa hopper, Spissistilus festinus (Say), nymphs were placed on greenhouse-grown 'Florida 77' alfalfa, Medicago sativa L., plants for three harvest periods. Higher populations of nymphs caused a corresponding increase in girdle numbers on the test plants. Nymphal populations significantly increased plant chlorosis and accelerated plant maturity. Although dry-weight yield was not affected, forage quality was reduced because of a decrease in protein concentration and an increase in neutral detergent fiber. Root carbohydrate levels and stem regrowth were both significantly lower under high population levels.