Resistance is a serious threat to transgenic cottons. Australian cotton growers are very familiar with the devastation that the industry can suffer from insecticide resistance, as in the Ord in the 1970s. Similarly, cotton growers are also well aware of the importance of transgenic cotton for reducing pesticide use in the industry. Unfortunately, transgenic plants are no less subject to selection for resistance than classical insecticides. A major pest of cabbage, the diamondback moth, has already evolved resistance to Bacillus thuringiensis (Bt) sprays in many cropping areas around the world. Bt-resistant diamondback moth larvae can be selected by and are completely resistant to transgenic plants that carry exactly the same Bt gene (&quote;CrylA&quote;) as is used in transgenic (INGARD) cotton (Metz, Roush, Tang, SheIton, and Earle, 1995 Molecular Breeding I: 309-317). There is every reason to suspect that a few cotton bollworms carry a resistance gene that is very similar to that in diamondback moth. Further, in contrast to insecticide sprays, the Bt toxin is continuously expressed in transgenic plants, which means that every insect feeding on them will be selected for resistance. This persistent exposure offers the potential of even stronger selection for resistance than would come from sprays. There is also evidence that genes for resistance to Bt may be more common than were genes for resistance to chemical insecticides, which could also give faster resistance. Thus, resistance management is at least as critical to transgenic crops as it has been for chemical insecticides.