Tarnished plant hugs, Lygus lineolaris (Palisot de Beauvois), were collected from eight different host plants and placed on four cotton genotypes in a greenhouse study at Stoneville, Mississippi, to determine if the host plants from which TPB (tarnished plant bugs) migrate influence the growth and fruiting of infested cotton. The genotypes were infested with 5th-instar nymphs of TPB at two stages of growth. The first infestation took place on June 5 in a greenhouse containing one-half of the study at the pinhead square stage while the adjacent greenhouse containing the remaining half of the study was infested one week later on June 12.

TPB nymphs significantly reduced plant height, squaring, blooms, and bolls in the early stages of plant development and maturation. This was followed by a period of rapid "catch-up" by the treated plants. The Most detectable effect of nymphs was on squaring. Significant differences in squaring and subsequent flowering and number of bolls due to host sources was detected. Nymphs from tickseed (Coreopsis tinctoria) in general resulted in the shortest plants and the-least squares/plant in the early stages of plant development. Nymphs reared on the three legume species, the laboratory stock reared on pole beans (Phaseolus vulgaris), vetch (Vicia spp.), and white clover (Trifolium repens), resulted in the least damage and reduction in fruiting.