Monitoring of Arizona whitefly resistance to insecticides in 1994 and 1995 demonstrated a >100-fold resistance to what has been one of the most effective insecticide mixtures for controlling whiteflies: Danitol^® + Orthene^®. Evidence also pointed to cross-resistance to other synergized pyrethroids used to control whiteflies. Statewide monitoring indicated that growers in some areas of Arizona are running out of effective registered insecticides for controlling this pest. These findings have lead to intensive inter-agency collaborations in Arizona aimed at: obtaining registration of new selective insecticides and integrating them into a biologically-based whitefly management program; formulation, demonstration and area-wide implementation of integrated resistance management programs; and statewide education of cotton growers in whitefly management.