Standard weed control in glyphosate-tolerant (GT) crops has become a headache for growers in the United States. Many are wondering why glyphosate, an herbicide that has always been extremely effective, is beginning to fail them. “This is becoming a trend more so in the United States than in the rest of the world” says Ian Heap, director of the International Survey of Herbicide Resistant Weeds. “More GT crops are planted in the U.S. than anywhere else, and since it is possible to use nothing but glyphosate on these crops, many growers are doing just that.”