Source: Dr. Mark Loux, OSU Extension
We are starting to see the availability of soybean varieties with more than two herbicide resistance traits, which can expand the herbicide options, improve control, and allow multiple site of action tank mixes that reduce the rate of selection for resistance. One of these is the Enlist soybean, with resistance to glyphosate, glufosinate, and 2,4-D. As of this writing, full approval for the Enlist soybean is still being held up by the Philippines (because they can apparently). The other is the LL-GT27 soybean, which has resistance to glyphosate, glufosinate, and isoxaflutole (Balance). There is no label for use of isoxaflutole on this soybean yet, but it is legal to apply both glyphosate and glufosinate. In Ohio, as long as neither label prohibits applying a mixture of two herbicides labeled for a specific use, it’s legal to apply the mixture. So, it’s also legal to apply a mixture of glyphosate and glufosinate to the LL-GT27 soybean. There is no label that actually mentions or provides guidance for this mixture, which does not affect legality, but could affect who assumes liability for the recommendation to apply a mixture if that matters to you. Some seed companies are making the recommendation for POST application of the mix of glyphosate and glufosinate to the LL-GT27 soybean in printed materials. Our interpretation after discussion with ODA, is that these materials are essentially supplements to labels, and so the seed company would assume some liability for the recommendation.