ASSESSMENT OF DAMAGE CAUSED BY TARNISHED PLANT BUG AND ALFALFA PLANT BUG (HEMIPTERA, MIRIDAE) ON ALFALFA GROWN FOR FORAGE IN WISCONSIN

Relative damage to alfalfa due to feeding by the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae), and the alfalfa plant bug, Adelphocoris lineolatus (Goeze) (Hemiptera: Miridae), was assessed with alfalfa plants grown in field cages. Feeding by adults and nymphs of both species reduced dry weight and length of stems in established stands (at least 1 yr old) of alfalfa, but feeding had no consistent effect on percentage of crude protein. However, feeding by caged adult plant bugs caused a reduction in length of stem and biomass in newly seeded alfalfa and an increase in percentage of crude protein. Sprays applied at various stages of alfalfa development and plant bug population densities failed to show that either species reduced yield or quality during this 2-yr study.