Imidacloprid is widely used as a control for emerald ash borer, although little is understood about how it effects reduction in pest density. Circumstantial evidence suggests that adults are more susceptible to imidacloprid treatment than larvae, and that the pesticide causes both direct mortality and at lower levels, reduction in adult feeding. To quantify these effects, we used a petri dish bioassay to evaluate beetle mortality and leaf consumption on leaves of potted plants treated with a range of imidacloprid concentrations. Nominal treatment levels varied between 0.008 and 2.5 g/pot; actual concentrations of leaf residue were determined by ELISA. Results will suggest practical target values for the leaf imidacloprid concentrations at which feeding inhibition and mortality occur.