A Hose is a Hose? (Prostko)

Despite 15 years of on-farm use, I continue to receive frequent questions at winter grower meetings about cleaning sprayers of Valor residues.  The Valor label has very specific instructions about the correct method for sprayer clean-out.  These instructions are very labor/time intensive thus I am not sure if growers are willing to follow all the required steps, especially when in a hurry? Check out the June 3, 2013 UGA Weed Science Blog for the labeled instructions.  Valent also sells their own tank cleaner, creatively named Valent Tank Cleaner, to help with this problem.  Since the degree of tank-cleaning success seems to vary by grower, it might just be more of an art than science?

If you have a grower that continues to struggle with Valor clean-out issues, you might want to find out what kind of hoses are on the sprayer.  Although naked to the human eye, rubber hoses, especially older ones, often have cracks and crevices that can trap Valor residues which can then be released at a later date (Figures 1 and 2).  Valor-challenged growers might want to consider replacing older rubber hoses with new polyethylene hoses. Although they can be more expensive (~$3/ft), there is some evidence to suggest that this type of hose is less likely to hold on to herbicide residues.    

Figure 1.  Scanning electron micrograph of a brand new Goodyear rubber spray hose (black, Versigard, synthetic).  Photo courtesy of Drs. Gary Cundiff and Dan Reynolds, Mississippi State University, 2016. 

Figure 2.  Scanning electron micrograph of Goodyear rubber spray hose (black, Versigard, synthetic) used 8 times.  Photo courtesy of Drs. Gary Cundiff and Dan Reynolds, Mississippi State University, 2016.

Inzen Z Grain Sorghum and Zest Herbicide (Prostko)

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 that might be helpful to you:

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 that 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.  

UGA Weed Science Web-Page Updates (Culpepper and Prostko)

Numerous circulars and slide presentations have been added over the past few weeks for agent use on the UGA Weed Science Web-Page (www.gaweed.com).

Circulars (found on home page):

1.  Methyl bromide alternatives

2.  Weed control in broccoli, cabbage and cauliflower

3.  Weed control in watermelon

4.  Controlling Palmer amaranth in cotton

Slide Presentations (click weed management toolbar on homepage; then click slide presentations):

1. 2016 Cotton Weed Control
2. 2016 Fumigant Systems
3. 2016 Vegetable Pesticide Update: Weeds
4. 2016 Vegetable Weed Control
5. 2016 Watermelon Weed Update
6. 2016 Wheat Weed Control

7. Influence of Nozzle Type of Peanut Weed Control Systems

8. 2,4-D and Dicamba Resistant Soybeans in the Southeast

9. Influence of Tractor Speed and Boom Height on Spray Coverage