Corn farmer Jerry McCulley sprays the weedkiller glyphosate across his cornfield in Auburn, Ill., in 2010. An increasing number of weeds have now evolved resistance to the chemical.
Labels on bags of snack foods indicate they are non-GMO food products. This fall, Colorado and Oregon will be the latest states to put GMO labeling on the ballot.
Robyn Beck /AFP/Getty Images
A corn purchaser writes on his account in northwest China in 2012. In November 2013, officials began rejecting imports of U.S. corn when they detected traces of a new gene not yet approved in China.
A customer shops for produce at the Hunger Mountain Co-op in April 2013 in Montpelier, Vt. More than a dozen food cooperatives supported the bill that would require the labeling of genetically modified foods.