Combining glyphosate with other herbicides to increase the killing effect of the application has been used for many years. See our brochure on annual ryegrass management for specifics on this.
Earlier in the year, EPA allowed 15 states the green light to using Enlist Duo, a combination of glyphosate with a form of 2,4-D. But last week, the EPA filed suit to halt the distribution and sale of Enlist Duo, saying new information provided about the product by Dow ”that suggests (the) two active ingredients could result in greater toxicity to non-target plants.”
EPA plans further review while Dow seeks to find a way to get clearance for the product for the 2016 season, including suggesting it might be able to modify the formulation somewhat or stipulate use conditions for the product.