There are six weeds in Nebraska that are confirmed to be glyphosate resistant — marestail, common waterhemp, Palmer amaranth, kochia, common ragweed and giant ragweed.
Resistance to glyphosate is spreading, but in the near future, growers will have a new tool to combat these weeds in soybean fields. For the last three years, Amit Jhala, Nebraska Extension weed management specialist has researched the Balance GT soybean system at the South Central Ag Lab near Clay Center
Balance GT, a new soybean variety from Bayer Crop Science and MS Technologies, recently received import approval from China, Canada and the European Union, and pending EPA registration for the Balance Bean herbicide, will see commercial availability in the U.S. in the near future.
Balance GT is resistant to Balance Bean — the same as Balance Flexx, which is already labeled for use in corn. Balance Bean's active ingredient is isoxaflutole, an HPPD-inhibitor. This makes Balance GT the first soybean cultivar tolerant to residual herbicides applied preemergence.
"Overall isoxaflutole is very effective on waterhemp, common ragweed, marestail. And we already have all those weeds resistant to glyphosate. This is going to be a good player in overall soybean weed control in the future," Jhala says. Meanwhile, because it has stacked resistance to isoxaflutole and glufosinate, growers can follow up with a postemergence application of Liberty. "You can apply preemergence herbicide and follow with a post, and none of the active ingredients used are glyphosate. Once this is commercialized, I think this will provide a good option for glyphosate-resistant weeds we have in Nebraska."
"We've tested it the last three years and seen some really good results applying isoxaflutole as pre-emergence followed by single application of Liberty as an early postemergence before flowering. It has provided season-long weed control," Jhala adds.
However, he has also tank-mixed Balance Bean with other preemergence herbicides, like Valor, Fierce or Authority XL, followed by a single application of Liberty. This combination provides broad-spectrum weed control and adds additional modes of action in a herbicide program.
RECIPE MIX: Balance Bean (2 ounces) plus Fierce (3 ounces) was applied preemergence, followed by Liberty (29 ounces) applied postemergence per acre in Balance GT soybeans at UNL's South Central Ag Lab near Clay Center. (Photo by Amit Jhala)
"We are talking about at least three different modes of action. Isoxafluxtole is a group 27 HPPD inhibitor. When tank-mixed with Valor, a herbicide whose active ingredient, flumioxazin, is a PPO inhibitor, you have two modes of action. Then if you follow up with Liberty, you have three different modes of action without applying glyphosate," Jhala says. "If we apply Balance Bean along with the right herbicide followed by a postemergence application of Liberty, it can provide broad-spectrum weed control in soybean."
In the future, Balance GT soybeans with have triple-stack resistance to isoxaflutole (Balance Bean), glufosinate (Liberty) and glyphosate — meaning soybeans with stacked resistance to three active ingredients with three distinct modes of action.
"We've also tested isoxaflutole, glufosinate plus glyphosate-resistant Balance GT beans," Jhala says. "The idea is depending on your need, you can use Liberty, or you can use glyphosate for a postapplication. And you can apply isoxaflutole as a preemergence, which can provide good control. So for example, if Palmer amaranth is glyphosate-resistant, and glyphosate doesn't work, maybe Balance Bean applied preemergence followed by Liberty will work. It provides more modes of action in your overall herbicide program."
It's best to not rely on a single herbicide or herbicide-resistant trait; herbicide rotation is very important for long-term use of new technology.
To learn more, contact Jhala at [email protected]. You can also learn more at the Weed Management and Cover Crops Field Day coming up on June 28 at the South Central Ag Lab near Clay Center.