Grower acceptance of genetically engineered (GE) corn, soybean and cotton has certainly been dramatic since the introduction of this technology 13 years ago. Many growers have used these herbicide and insect traits to boost yields while reducing production costs with more environmentally friendly farming practices. 

A July report from the U.S. Department of Agriculture’s Economic Research Service indicates that the percentage of soybean acres planted with herbicide-tolerant traits increased from 54% in 2000 to 91% in 2009.

During the same period, corn acres planted with one or more GE traits increased from 25% to 85%. In 2009, 17% of the acreage was planted with insect-resistant Bt hybrids, 22% with herbicide-tolerant hybrids and 46% with stacked hybrids that include both herbicide- and insect-resistant traits.

While the acreage of herbicide-tolerant crops continues to grow, weed scientists continue to voice concerns about the growing impact on resistant weeds and the reluctance on the part of growers to use alternative herbicides. While growers are sold on this weed-control chemistry, overuse may force the industry to develop new approaches to weed control.

To overcome a growing concern about weed species becoming immune to glyphosate, weed specialists in a half-dozen states recently released a study on glyphosate resistance management strategies. Some 1,200 growers in these states were asked how they used glyphosate and when they applied the herbicide.

The major use of glyphosate was as a burndown application with cotton and soybeans. Between 54% and 63% of growers made one or two post-emergence glyphosate applications in…