Tuesday, January 17, 2012

Another Reason to Avoid GMOs: Bt Toxin Superpests

This is hardly breaking news, but worth remembering when deciding if you want to eat food processed with Bt corn or soy.  At the end of last year, both Grist and GM Freeze wrote articles about insects developing resistance to genetically modified Bt crops.  The following is an excerpt from GM Freeze:
Corn Rootworm

Scientists have confirmed five incidents of insects evolving resistance to Bt toxins in the field to date: Bt cotton in India (2010) and US (2008), moth pests in maize in Puerto Rico (2007) and South Africa (2007) and a beetle pest in maize in the US (2011).

Reasons for resistance developing are:
  • Failure to provide adequate non-GM refuges in GM crops to ensure non-resistant adult insects can survive to breed with resistant ones so that the resistance gene does not become dominant. Refuges are required by US laws that are widely flouted.
  • Levels of Bt toxin in the crops too low to deliver lethal doses to pests. Sub-lethal doses mean resistance can develop as pests survive, mate and pass on the resistance gene. If the number of resistant individuals is high they can multiply quite rapidly and become dominant.
This failure of Bt crops goes hand in hand with a separate superweed problem affecting Monsanto's Roundup Ready line of herbicide resistant crops. The moral of this story: genetic tinkering has a host of unintended consequences, some of which you can plan for (as in the case of non-GM refuges, which demonstrates another issue of whether or not companies will comply with knowledge-based regulations) and some of which you can't.  Since the yields of these crops are the same or worse than the organic alternative, why not just skip the GMOs altogether?

If you would like to know what's in your food, join our GMO Activist Project and add your voice to the public outcry to label genetically modified foods.  Check out our GMO resource page and take action at Just Label It.  If you want to learn more about the dangers of GMOs, register for our Winter Conference with keynote Jeffrey Smith, the leading spokesperson on the health dangers of genetically modified organisms.

Have a great rest of your week!

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