In studies conducted in eastern Washington, seven species of weeds provided the food source of pre-overwintering lygus bugs,Lygusspp. The two major weed species were volunteer alfalfa,Medicago sativa, and lambsquarters,Chenopodiumspp. Winter survival of lygus bugs feeding on several species of weeds in the fall did not differ significantly. Winter survival of lygus bugs was low when the material in which the lygus bugs were overwintering was maintained under 10% of dry weight. Deciduous orchard duff was found to be the major overwintering site of adult lygus bugs, but considerable numbers overwintered in large mullein,Verbascum thapsisL., plants.