Researchers have studied cotton (Gossypium hirsutum L.)  response to loss of fruiting structures by manually removing squares (floral buds) and bolls (fruit) to simulate insect injury, but plant responses to damage by pest species such as tarnished plant bug (Lygus lineolaris Palisot de Beauvois) may not be as straightforward as manual removal because of the insect’s feeding habits. We report results from a 2 year study in Arkansas that examined effects of early square loss - removed either by feeding by tarnished plant bug or manually by crushing - on cotton development and yield.  Injury treatments were initiated when first squares were visible and continued weekly for 3 weeks.  All visible squares were crushed on each treatment date for the manual treatment and for plant bug treatments, 3 nymphs, 2^nd to 4^th instar, were released per plant.  Plant response from the 2 injury treatments was compared to plants protected by insecticide.  Differences in square shed were noted between treatments as well as crop delay as measured by days to physiological cutout (nodes above white flower=5). Significant differences in final plant structure between injury treatments also were observed.  Yield data collected over consecutive harvest dates indicated time-dependent compensation.