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Evolution gives insect pests the upper hand Study confirms that pest insects are evolving resistance to GM Bt crops

Breaking News (10 Oct 2017)

Press contact: Liz O'Neill 07811 211 404, liz[at]

A new study published today in the journal Nature Biotechnology has confirmed a huge increase in the number of pest insects that have evolved resistance to the GM Bt crops engineered to kill them.

Researchers at the University of Arizona showed that over half of the Bt crop cases they studied (19 out of 36) showed either resistance that substantially reduced the efficacy of Bt crops (16 cases) or showed early warning signs of resistance (three cases). This is a marked contrast to similar studies in 2005, which identified only three cases of resistance.

GM Freeze Director Liz O’Neill commented:

This study confirms a very simple truth: if you try to outwit nature, it’s evolution that wins.

We already know that if you grow herbicide tolerant GM crops you get herbicide resistant weeds. Now we have clear confirmation that the pattern repeats itself with insecticide-producing GM Bt crops. The author of the study described measures that have in some cases delayed the development of resistant insects by a few years as “a big win”. That tells us all we need to know about the GM industry’s vision for the future of farming, biodiversity and our natural environment.


For more information, please contact Liz O’Neill, 07811 211 404, liz[at]


GM Freeze is the UK umbrella campaign on GM food, crops and patents. GM Freeze is working to create a world in which everyone’s food is produced responsibly, fairly and sustainably.

Insect Resistance to Transgenic Crops: Second Decade Surge and Future Prospects is published 10 October 2017 in Nature Biotechnology.