Biotech Updates

Study on High Dose/Refuge Strategy for IRM of Bt Plants with Single or Pyramided Genes

October 31, 2012

The U.S. Environmental Protection Agency (USEPA) recommends application of high dose/refuge strategy in insect resistance management (IRM) of Bt plants. This strategy was first employed for Bt plants expressing one Cry protein. Scientists Aiko Gryspeirt and Jean-Claude Gregoire from Belgium evaluated the efficiency of high dose/refuge strategy in Bt plants expressing one or two Cry toxins.

Using a mathematical model, they assessed whether two toxins have to be present in high concentrations and the effect of the relative size of the refuge zone on the evolution of resistance and population density. The results suggest that Bt plants with one toxin must be expressed in high concentration for resistance management. For Bt plants with pyramided Bt genes, one toxin could be expressed in low concentration if the toxins are used for the first time, and a small refuge zone is suitable.

Read the abstract at