Should EPA double the percent of corn refuges?
Tabashnik pointed to a case in Puerto Rico, where adequate refuges were not planted. Within a few years, the pests evolved resistance and devoured the Bt corn plants. The biotechnology companies voluntary stopped selling Bt corn seed there, but five years later, the insects remain resistant to the toxin.
Although biotech companies recently starting selling some varieties of Bt corn that produce combinations of Bt toxins, Tabashnik said, the resistance to one toxin still raises concerns.
"You can think of the multi-Bt toxin approach as a pyramid: The base has to be stable. If one of your building blocks, which is susceptibility to Cry3Bb1, is crumbling, you have a problem. Resistance to any one toxin jeopardizes the effectiveness of the whole system."
"We're at a tipping point where decisive action can provide long-term benefits and avoid loss of an environmentally friendly tool for pest control."
- No El Niño in 2014? Drought-weary California in trouble
- Suspected Bt corn rootworm resistance in Pennsylvania
- Soybean aphid numbers on the rise
- BioNitrogen to build second fertilizer plant in Texas
- Commentary: Setting the record straight on 'Waters of the U.S.'
- Anti-GMO proposal denounced at Safeway shareholder meeting