U.S. farmers have embraced genetically engineered (GE) seeds in the more than 15 years since their commercial introduction. Herbicide-tolerant (HT) crops, developed to survive application of specific herbicides that previously would have destroyed the crop along with the targeted weeds, provide farmers with a broader variety of options for effective weed control. Based on USDA survey data, HT-only corn dropped from 21 percent of planted corn acreage in 2012 to 14 percent in 2013. Insect-resistant crops contain a gene from the soil bacterium Bt (Bacillus thuringiensis) that produces a protein that is toxic to specific insects, protecting the plant over its entire life. Use of Bt-only corn dropped from around 16 percent of planted corn acreage in recent years to 5 percent in 2013. Adoption of “stacked” gene corn varieties (with both HT and Bt traits), though, increased sharply in 2013, reaching 71 percent of planted corn acres (up from 52 percent in 2012). Adoption of all GE corn, taking into account the acreage with either or both HT and Bt traits, reached 90 percent of U.S. corn acreage in 2013. This chart comes from the ERS data product, Adoption of Genetically Engineered Crops in the U.S., updated July 2013.