The successful management of insecticide resistance benefits from a knowledge of the biological characteristics of pests that promote or retard resistance development. For the whitefly Bemisia tabaci (= B. argentifolii), these factors include its haplo-diploid breeding system, its breeding cycle on a succession of treated or untreated hosts, and its occurrence on and dispersal from high value crops in greenhouses and glasshouses. These factors, in conjunction with often intensive insecticide use, have led to severe and widespread resistance that now affects several novel as well as conventional control agents. Under the ecological conditions prevailing in some cotton-growing areas of Israel, there is evidence that even restricting new insecticides to a single application per year does not suppress resistance indefinitely. The implications of these findings for comparable cotton-growing systems in the southwestern USA are discussed.