Zidua Labeled for Use in Soybean (Prostko)

Zidua 85WG (pyroxasulfone) recently received a registration for use in soybean.  You may recall that back on January 10, I published some information on this blog about its potential uses in field corn.  Zidua provides residual control of certain annual grass and broadleaf weeds, including Palmer amaranth (Figure 1).  Zidua can be applied PPI, PRE, or EPOST at rates ranging between 1.0 to 2.1 oz/A on coarse soil types (~$6.50/A to $13.65/A).  Zidua should NOT be applied from soybean emergence (cracking) through the unifoliolate stage of growth or unacceptable crop injury may occur. A copy of the complete supplemental soybean label can be found at the following location: http://www.cdms.net/LDat/ldAMK004.pdf

Additionally, there have been revisions to the crop rotation restrictions for Zidua.  Current crop rotation restrictions for Zidua can be viewed at the following location:
http://www.cdms.net/LDat/ldAMK003.pdf

Figure 1.  Weed Control in Soybean with Zidua 85WG @ 2 oz/A.

Fierce Labeled for Use in Soybean (Prostko)

Fierce 76WG recently received a label for preemergence (PRE) use in soybean.  Fierce 76WG is a combination of 33.5% Valor (flumioxazin) + 42.5% Zidua (pyroxasulfone).  The normal use rate of Fierce for coarse soil types is 3 oz/A.  Fierce 76WG @ 3 oz/A is equivalent to Valor 51WG @ 2 oz/A + Zidua 85WG @ 1.5 oz/A.  Generally, Fierce has looked impressive in my field trials (Figure 1).  A copy of the supplemental Fierce soybean label can be found at the following location:
http://www.valent.com/Data/Labels/2013-FIE-0013%20Fierce%20Soybean.pdf

Figure 1.  Fierce for Weed Control in Soybean - 2012

Currently, there are several PRE soybean herbicides that contain the active ingredient flumioxazin (Envive, Fierce, Valor, Valor XLT).  There is no question that one of the most effective herbicide programs for the control of Palmer amaranth in soybean would be to use one of these flumioxazin-containing products (PRE) then follow with Reflex (POST).  However, this progam should not be encouraged since all of these herbicides have the same mode of action (PPO-inhibitor).  Growers in a soybean/corn rotation might get away with this program since Reflex and Valor are not being overused.  But, growers in a cotton/peanut rotation, who are relying heavily on Valor and Reflex, should avoid their overuse in soybean.  Some specific recommendation's for soybean growers who want to protect Valor and Reflex are presented in Figure 2. 

Figure 2.  Soybean Herbicide Options That Help Protect Valor and Reflex



Counter/Herbicide Interactions in Field Corn (Prostko)

It is very important to remember that if a field corn grower wants/needs to use an in-furrow application of Counter 20G, he cannot use certain herbicides (Figure 1).  This negative insecticide/herbicide interaction is more commonly associated with the ALS-inhibiting herbicides (Accent, Beacon, Steadfast Q) but can also occur with certain HPPD-inhibitors (Callisto, Halex GT) and PPO-inhibitors (Sharpen, Verdict).  In one of my field corn trials conducted in 2012, a Counter/Steadfast interaction resulted in a 40% yield loss.  The manufacturers of Counter 20G (AMVAC) have put together a excellent publication to address this issue (Figure 2).  

Figure 1.  Field Corn Injury Caused By Counter/ALS Herbicide Interaction.

 



Figure 2.  AMVAC Counter/Herbicide Publication

Postemergence Field Corn Herbicides (Prostko)

Not sure what happened, but the table below was accidently left out of the 2013 UGA Pest Control Handbook.  It should help you address questions about times of application in field corn.

 

Table 1.  Times of Application/PHI for Postemergence Herbicide Labeled for Use in Field.
 

Herbicide	Field Corn Stage of Growth		PHI (DAYS)	Grazing, Feed, Forage, Hay, Silage Interval (days)
	Earliest	Latest
Accent Q	1-2 leaf	20” or V6 20-36” or V10 - drops		30
Aim	spike	V8 V8-14 leaf collars - drops	14 leaf collars	14
Atrazine	PPI/PRE	12”		grazing = 21 forage = 60
Basagran	1-2 leaf	NL		12
Callisto	pre	30” tall or 8 leaf stage	45	45
Capreno	V1	V6 V6-V7- drops		45
Clarity	1-2 leaf	5th leaf or 8” tall 8-36” tall drops
Dual Magnum	PPI/PRE	40” tall		30
ET	Spike	V4 V4-V8 - drops	90	50
Halex GT	Spike	30” or V8	45	45
Impact/Armezon	spike	??	45	45
Laudis	1-2 leaf	V8		45
Liberty	spike	24” or V7 24-36” - drops	70	60
Prowl H20	spike	30” or V8		21
Realm Q	1-2 leaf	20” or V7	70	45
Resolve Q	1-2 leaf	20” or V7		30
Roundup	spike	30” or V8 30-48” - drops	50	50
Sandea/Permit	spike	layby		30
Status	V2	5th leaf or 8” 8-36” or V10 - drops	72	32
Steadfast Q	1-2 leaf	20” or V6		30
Warrant	spike	24” 24-30” - drops		40
Zidua	spike	V4

¹NL = none specifically listed on the label. 

 

Valor Application Method (Prostko)

Not sure what's going on in some counties so here is a friendly reminder that UGA does not recommend that Valor be applied preplant incorporated (PPI) in peanut for 2 very good reasons: 1) Valor is not labeled for this type of application and 2) PPI applications provide significantly less control of of Palmer amaranth than PRE applications (Figure 1).

Gramoxone/Reflex Tank-Mixtures (Prostko)

Over the last few years, growers have experienced a few problems when tank-mixing Gramoxone (paraquat) + Reflex (fomesafen).  In order to prevent these potential compatibility problems, consider the following recommendations developed by Syngenta:

1) When tank-mixing Gramoxone and Reflex, use a non-ionic surfactant (NIS) that contains a minimum of 80% active ingredient.

2) With spray volumes of 10 GPA or more, use NIS at 2 qt/100 gal (0.5% v/v).  Use 1 gal/100 gal (1% v/v) when spraying less than 10 GPA.

3) Mix chemicals in the following order:

a) Add half of the required amount of clean water to the spray tank.

b) Start the sprayer agitation system and continue agitation throughout mixing and spraying.

c) Add the required amount of non-ionic surfactant to the spray tank.

d) Add the required amount of Reflex to the spray tank.

e) Add the required amount of Gramoxone brands to the spray tank.

f) Add the remaining amount of clean water to the spray tank.

Zidua® Herbicide (Prostko)

Just got through looking at some popular press articles and noticed that there were several advertisements for a new herbicide sold under the trade name of Zidua®.  The UGA Weed Science Team has been evaluating this herbicide for several years so we have some good data for sure.  Here are a few things you might need to know about this new product:

Trade Name: Zidua®

Active Ingredient: pyroxasulfone (It was tested under experimental number KIH-485)

Manufacturer: BASF

Mode of Action:  Inhibits the synthesis of very long chain fatty acids.  Same mode of action as Dual and Warrant. (MOA = 15)

Formulation: 85WDG

Typical Use Rate: 1-2 oz/A

Estimated Cost: $6.50/oz

Current Registrations: Field Corn (Zidua® is listed in Field Corn section of the 2013 UGA Pest Control Handbook)

Future Registrations: soybean, sunflower, wheat, cotton (?), peanut (?)

Field Corn Application Methods:  PPI, PRE, or POST but does not have POST activity.  Only provides residual control.

Weeds Controlled:  Small seeded broadleaf weeds and annual grasses.  In UGA tests, it has provided excellent control of Palmer amaranth

General Comments:

Zidua will compete for market share against similar herbicides such as Dual Magnum or Warrant.  The one big advantage that this herbicide has over these is that its use rate in much lower.  I am not expecting Zidua to change the world but it does give growers another residual herbicide option to choose from.  The active ingredient, pyroxasulfone, will also be available in the following herbicide pre-mixes:

Anthem = pyroxasulfone + Cadet (FMC)

Anthem ATZ = pyroxasulfone + Cadet + Atrazine (FMC)

Fierce = pyroxasulfone + Valor (Valent)

Registrations for the above herbicides are pending.  For a copy of the current Zidua label, please refer to the following link:

http://www.cdms.net/LDat/ldAMK000.pdf

Check out the following Zidua® pictures from my 2012 field research: