Host preference tests were conducted onLygus hesperusKnight andL. elisusVan Duzee in cotton fields interplanted with 20-ft wide strips of alfalfa at 130- to 540-ft intervals and in various patterns of alfalfa row spacing. The distinct preference of lygus bugs for alfalfa over cotton was significantly demonstrated even when samples were taken in the 2 crops 3 ft apart. These studies demonstrate the efficiency of using alfalfa as a trap crop for lygus bugs in cotton.