Laboratory bioassays were conducted to evaluate response of tarnished plant bug to insecticides that induce changes in feeding behavior. Both imidacloprid and pymetrozine administered to adults in a sucrose/dye mixture resulted in reductions in excretion of fecal deposits over 4 and 8 day test periods. A conventional poisoning effect was observed at higher concentrations for imidacloprid. Results from field trials with caged tarnished plant bugs indicate additions of sucrose or molasses to spray mixtures of Provado improve efficacy at low rates (0.02 to 0.025 lb a.i./ac) but not at higher rates (0.045 lbs a.i./ac). Data suggest that conventional spray and count methods are not sufficient to adequately evaluate insecticides with novel modes of action that affect feeding behavior.