Insecticidal transgenic plants: are they irresistible?

Transgenic plants producing Bacillus thuringiensis toxins show great promise as insect control agents, provided that effective resistance management strategies are implemented early in their product cycle. To be effective, these strategies require detailed knowledge of the toxins’ mode of action and of the insect’s genetic repertoire of potential resistance genes, knowledge which is still incomplete even in the best studied systems. Unfortunately, insects show great variability in their genetic responses to selection by Bt toxins. At the present time there is no single proven resistance management strategy that may be recommended as a general approach to avoid resistance to transgenic Bt plants.