Inzen Z Grain Sorghum And Zest Herbicide

The EPA recently approved the use of Zest herbicide for use in the Inzen Z ALS-tolerant grain sorghum system.  The following are some questions and answers from UGA Extension Weed Sceintist Dr. Eric Prostko that may be helpful to us:

1) What is Inzen Z herbicide-tolerant grain sorghum?

Inzen Z herbicide-tolerant grain sorghum is sorghum that has been traditionally bred (i.e. NON-GMO) for resistance to certain ALS-inhibiting herbicides. This technology was originally developed by Kansas State University and licensed to both DuPont and Advanta Seeds. The resistance to these herbicides came from ALS-resistant shattercane, a close relative of sorghum.

2) What is Zest herbicide?

Zest is a new liquid formulation of the active ingredient, nicosulfuron.  You may recall that nicosulfuron is the active ingredient of the old corn herbicide sold under the trade name of Accent. Nicosulfuron is also an ingredient of several other corn herbicide pre-mixes such as Steadfast Q (nicosulfuron + rimsulfuron) and Revulin Q (nicosulfuron + mesotrione).  The use of Zest herbicide on conventional grain sorghum varieties will result in severe crop injury/death (Figure 1).  At the time this blog was penned, a Zest label was not yet available.  The official Zest label is anticipated in April?


Figure 1. Weed control in Inzen Z grain sorghum with nicosulfuron in 2013. Conventional sorghum variety in right picture was completely killed by nicosulfuron.

3) Has the Inzen Z herbicide-tolerant sorghum been tested system in Georgia?

Yes! UGA weed scientists have worked with this technology for several years.  When available, it will be very beneficial for grain sorghum growers who struggle with Texas millet/buffalograss control.  However, resistance management will be crucial to the long-term viability of this technology. Georgia growers will be encouraged to start clean, use a residual herbicide at planting (Dual or Warrant), tank-mix atrazine with the POST application of Zest (Figure 2), and rotate crops.


Figure 2. Weed control in Inzen Z grain sorghum – 2014.

4) Will Inzen Z grain sorghum hybrids be available to Georgia growers?

Since Georgia is not a leading producer of grain sorghum (only 50,000 acres planted in 2015). I expect our growers will be on the end of the list in terms of getting hybrids that are well-adapted to our region.  In 2016, Advanta (Alta Seeds) is scheduled to release one Inzen Z hybrid to a small group of growers in Kansas and Texas.  In 2017, Advanta hopes to launch an additional two Inzen Z hybrids. Pioneer will potentially launch in 2018.


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