Managing pests and their resistance to Bacillus thuringiensis: Can transgenic crops be better than sprays?

Insecticidal toxins from Bacillus thuringiensis (Bt) can now be deployed either in sprays or transgenic plants. Some entomologists and environmentalists have argued that the sprays are preferable to plants because they are less likely to cause resistance. However Bt sprays are not generally competitive with chemical insecticides and seem unlikely to displace them. In contrast, transgenic plants appear to be sufficiently effective to displace chemicals, making such plants attractive from the standpoint of environmental protection. Further, simulation models using data from the diamondback moth and a laboratory experiment using the Indianmeal moth suggest that wider at least some circumstances, transgenic plants bearing only one Bt gene may be more effective than sprays for delaying resistance to Bt Resistance in a laboratory‐selected strain of the Colorado potato beetle is especially interesting because a strain that can survive Bt sprays and develop to maturity cannot develop successfully on transgenic pl...