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.
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!