Post emergence grass control has long been an issue in grain sorghum. In 2021, the industry brought three technologies—Inzen sorghum from Corteva, igrowth sorghum from Advanta Seeds and Double Team Sorghum from S&W Seed to the market. Of these, only igrowth sorghum was readily available in large quantities.
This year Double Team seed will be more readily available to growers. S&W Seed, through its Sorghum Partners Brand, will have five Double Team hybrids to choose from in 2022 ranging in maturity from very early to medium maturity. However, it is anticipated that demand will exceed supply so growers are encouraged to book seed now.
The herbicide used with the Double Team seed is quizalofop, sold by ADAMA under the trade name FirstAct. Quizalofop is a proven post emergence grass herbicide that has been used for years in broadleaf crops such as cotton, soybeans and sunflowers. The herbicide has been sold under various trade names with Assure II being the most common.
It is important to note that FirstAct will only control grass and will not control broadleaf weeds. Injury to the crop can occur if FirstAct is applied to small grain sorghum. The recommendation is to apply FirstAct only after the plant height has reached 11 inches or is at the 8-leaf stage.
In addition, broadleaf herbicides should not be mixed with and applied with FirstAct. Mixing broadleaf herbicides such as 2,4-D, dicamba or Huskie can greatly lower the effectiveness of FirstAct on grass. Broadleaf weed control products should be applied either several days prior or several days after FirstAct application. In most cases, applying broadleaf herbicides prior to FirstAct application will be best if broadleaf weed control is needed.
Keep in mind FirstAct should not replace your pre-herbicide application. Pre-herbicides are necessary in sorghum to control broadleaf weeds and to provide another mode-of-action for grass control.
As with all post emergence herbicides, FirstAct will work best on grass that is small. For best control, use crop oil concentrate and apply in a minimum of 10 gallons of water and under drought stress conditions 10 gallons of water is highly recommended.
There are important stewardship guidelines to prevent weed resistance from developing that should be closely followed with Double Team as well as the other herbicide technology sorghum systems. See Sorghum Partner Double Team website for more information on stewardship and other information regarding this technology.
It is especially important to prevent resistance to all herbicide technologies mentioned here from developing in Johnsongrass and shattercane. Make sure all Johnsongrass and shattercane is controlled in and around fields where Double Team, Inzen or igrowth sorghum technologies are being used during the time that the grain sorghum is flowering and shedding pollen. Sound stewardship practices will allow these technologies to be effective for many years to come.
Editor’s note: Brent Bean, Ph.D., is Sorghum Checkoff Director of Agronomy, Lubbock, Texas. For more information visit www.sorghumcheckoff.com.
