By P.J. GRIEKSPOOR
Great Plains grain sorghum growers just got some great news in their quest for a chemical weapon against grasses in the post-emergent crop.
DuPont Crop Protection has obtained the establishment of tolerances by the U.S. Environmental Protection Agency that will facilitate the use of herbicides containing nicosulfuron and rimsulfuron on sorghum varieties containing a herbicide-tolerance sorghum trait developed at Kansas State University that is being commercialized by DuPont.
The technology is non-GMO because the genetic tolerance to ALS herbicides was found in a wild relative of grain sorghum. Kansas State University sorghum breeder Kassim Al-Khatib first found the wild sorghum trait that made it resistant to ALS class herbicides in 2005. K-State partnered with DuPont and Advanta to develop technology on the seed side to come up with varieties carrying that trait.
DuPont developed grain sorghum carrying the trait and named it Inzen. What followed was the effort to develop herbicides containing active ingredients that would not harm that sorghum but that could kill grasses in sorghum fields.
Now that tolerances have been established, the next step is for DuPont, Advanta and EPA to work together to agree upon management practices and labeling that will help growers use the new technology in a way that will ensure the long term viability of the resistant trait.
"We anticipate full registration in about three months," said Wayne Schumacher with DuPont. "Seed companies will be looking at 2015 field trials and commercializing hybrids and will be have a data rview coming up pretty soon. With it being non-GMO, we have fewer regulatory hoops to jump through. Canada does have a novel trait regulation and they are reviewing the package to make sure that there is nothing there that causes allergies or whatever," he added.
"We are bringing two new ingredients to the market. Nicosulfuron will be the active ingredient that will be found in Zest, the post-emergence herbicide for over the top grass control," he said.
Nicosulfuron and rimsulfuron have shown excellent control of many of the annual grasses that rob sorghum yields, including crabgrass, barnyard grass, singalgrass and panicum.
Schumacher said the current work being done with EPA to work out labeling and best management practices to assure that resistance will not develop.
"Delays at EPA have given us opportunity to tap into local expertise," Schmacher said. "We are spending a lot of time developing local recommendations, sorghum varieties are very different from south Texas to Kansas and Nebraska. Since 2005, 10 years from initial cros, we have worked to build ALS tolerance into sorghum. That is a lot of time and investment and we want it to be viable for a good, long time."
These herbicides also will offer outstanding crop rotation and recropping flexibility. They can be tank-mixed with other herbicides, insecticides and fungicides registered for use on sorghum. And they will provide an alternate mode of action that will aid in reducing glyphosate resistance and will control labeled grasses that are glyphosate-resistant.
DuPont has been working with National Sorghum Producers and Sorghum Checkoff, and the producer organizations have been involved in the meetings between DuPont, the EPA and USDA.
"They will be helping to provide education and training this fall and winter as well to help make sure that producers get the stewardship training they need about Inzen," Schumacher said.
Nicosulfuron and rimsulfuron should not be used on sorghum that does not contain the Inzen herbicide tolerance trait because it will cause severe crop injury, Schumacher warned.