Assessing the risk of pest resistance evolution to Bacillus thuringiensis engineered into crop plants: A case study of oilseed rape

Existing and novel Bacillus thuringiensis toxin-coding genes may be utilised in transgenic oilseed rape to control many of the important insect pest species on the crop, worldwide. Location-specific ecological crop assessment must be used to evaluate the need and possibilities for managing resistance evolution in the target pests, and to ensure sustainability of the control strategy. In some cases, at least, it appears that durable control could be attained in oilseed rape by an integrated control approach, including the use of transgenic crop and among it, about 10% of non-transformed seed to provide refugia for susceptible insect genotypes. Seed mixtures or strip intercropping would be easy to handle also in practice.