In 1995 we initiated a resistance management program aimed at sustaining the efficacy of imidacloprid. This paper delineates the groundwork for the program, and describes methodological and conceptual advances toward our goal. Bioassay methods developed for adult whitefly consisted of a 1 day hydroponic uptake procedure using cotton seedlings. A reliable mortality criterion was also established. Results from a statewide survey suggested slight geographic variation in whitefly susceptibility to imidacloprid. Long-term studies will 1) evaluate the risk of resistance to whitefly populations in commercial greenhouses, and relate this to field populations, and 2) characterize the development of resistance in relation to cropping systems and spatial dynamics of whitefly. The overall objective of these investigations is to determine if a sustainable use strategy can be identified for imidacloprid.