Dow AgroSciences, which sells seeds and pesticides to farmers, made contradictory claims to different parts of the U.S. government about its latest herbicide. The Environmental Protection Agency just found out, and now wants to cancel Dow's legal right to sell the product. The herbicide, which the company calls Enlist Duo, is a mixture of two chemicals: glyphosate (also known as Roundup) and 2,4-D. It's Dow's answer to the growing problem of weeds that are resistant to glyphosate, which has become the weed-killing weapon of choice for farmers across the country. The new formulation is intended to work hand-in-hand with a new generation of corn and soybean seeds that are genetically engineered to tolerate sprays of both herbicides. When Dow applied for permission to sell Enlist Duo in 2011, it told the EPA that this mixture of glyphosate and 2,4-D is no more toxic than the two chemicals are, if considered separately. The EPA ... approved the new herbicide just over a year ago, [yet later] discovered that Dow had been telling the U.S. Patent and Trademark Office a different story. Dow's patent application for Enlist Duo claims that this mixture of chemicals does, in fact, offer farmers something new: "synergistic herbicidal weed control." Last month, the EPA asked Dow to explain these synergistic effects. On Nov. 9, the company responded with what the EPA calls "extensive information." The EPA, after taking a look at the new information, decided to ask the court for a chance to reverse its approval of Enlist Duo.