Steward™ is a new insect control product developed by DuPont Agricultural Products that has proven to be highly effective on Lepidoptera pests in cotton and other crops. Steward™ has also demonstrated good activity on tarnished plant bug (Lygus lineolaris) while preserving a wide range of beneficial insects and spiders. Field and laboratory studies were conducted in 1997 and 1998 to evaluate Steward™ for the control of tarnished plant bug in cotton. Contact and residual activity of Steward™ on tarnished plant bugs, beneficial insects, and parasitic wasps was evaluated in the laboratory by applying Steward™ at use rates of 0.065 to 0.11 lb ai/A directly to the insects as well as by introducing the insects to treated leaf tissue. In small-plot, field studies, Steward™ was evaluated at rates of 0.065 to 0.11 lb ai/A and compared to oxamyl (Vydate^®; CLV), spinosad (Tracer^®;), acephate (Orthene^®;), and chlorfenapyr (Pirate^®;). In the laboratory studies which evaluated contact activity, Steward™ at use rates of 0.09 and 0.11 lb ai/A provided 82-86% control of tarnished plant bug adults and 33 to 43% control of plant bug nymphs. Residual studies conducted in the laboratory indicated poor control of tarnished plant bug nymphs and adults at all rates of Steward™. In the field studies, Steward™ applied at rates of 0.09-0.11 lb ai/A provided tarnished plant bug (adult) control that was equal to and often superior to the commercial standards.