Toxins 2012, 4(10), 810-835; doi:10.3390/toxins4100810
Article

Effectiveness of the High Dose/Refuge Strategy for Managing Pest Resistance to Bacillus thuringiensis (Bt) Plants Expressing One or Two Toxins

1,2,* email and 1email
Received: 6 June 2012; in revised form: 21 September 2012 / Accepted: 8 October 2012 / Published: 18 October 2012
(This article belongs to the Special Issue Insecticidal Toxins)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: To delay resistance development to Bacillus thuringiensis (Bt) plants expressing their own insecticide, the application of the Insect Resistance Management strategy called “High Dose/Refuge Strategy” (HD/R) is recommended by the US Environmental Protection Agency (US EPA). This strategy was developed for Bt plants expressing one toxin. Presently, however, new Bt plants that simultaneously express two toxins are on the market. We used a mathematical model to evaluate the efficiency of the HD/R strategy for both these Bt toxins. As the current two-toxin Bt plants do not express two new Cry toxins but reuse one toxin already in use with a one-toxin plant, we estimated the spread of resistance when the resistance alleles are not rare. This study assesses: (i) whether the two toxins have to be present in high concentration, and (ii) the impact of the relative size of the refuge zone on the evolution of resistance and population density. We concluded that for Bt plants expressing one toxin, a high concentration is an essential condition for resistance management. For the pyramided Bt plants, one toxin could be expressed at a low titer if the two toxins are used for the first time, and a small refuge zone is acceptable.
Keywords: insect resistance management; population dynamics; population genetics; Bacillus thuringiensis; High dose/Refuge strategy; Bt plants; two toxins
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MDPI and ACS Style

Gryspeirt, A.; Grégoire, J.-C. Effectiveness of the High Dose/Refuge Strategy for Managing Pest Resistance to Bacillus thuringiensis (Bt) Plants Expressing One or Two Toxins. Toxins 2012, 4, 810-835.

AMA Style

Gryspeirt A, Grégoire J-C. Effectiveness of the High Dose/Refuge Strategy for Managing Pest Resistance to Bacillus thuringiensis (Bt) Plants Expressing One or Two Toxins. Toxins. 2012; 4(10):810-835.

Chicago/Turabian Style

Gryspeirt, Aiko; Grégoire, Jean-Claude. 2012. "Effectiveness of the High Dose/Refuge Strategy for Managing Pest Resistance to Bacillus thuringiensis (Bt) Plants Expressing One or Two Toxins." Toxins 4, no. 10: 810-835.


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