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 that farmers have used separately for many years: 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.