Counter/Herbicide Interactions in Field Corn (Prostko)

In a previous blog (March 1, 2013), I discussed the potential problems associated with the the use of Counter and certain postemergence herbicides in field corn. The following are some answers to questions you might get asked about this problem at this time of year:

1) Why can't certain herbicides be used after an in-furrow (INFR) application of Counter in field corn?

Organophosphate (OP) insecticides, amino acid synthesis (ALS) and certain pigment (HPPD) inhibitors are metabolized in field corn by the same enzyme system (cytochrome P450 monooxygenase).  When these pesticides are used sequentially (INFR + POST) in field corn, this enzyme system cannot successfully metabolize both active ingredients.

2) How bad would corn yields be affected if this accidentally happened?

Research results from 2012 would suggest that yield losses could exceed 40% if an inappropriate herbicide was used following an INFR application of Counter.

Figure 1.  Corn yield response to the interaction of Counter (INFR) and Steadfast (POST).

3) What herbicides can be applied in field corn if Counter is used INFR?

The following herbicides, commonly used in GA field corn production systems, are safe to use if Counter is applied INFR:

Aim, Atrazine, Clarity, Dual Magnum, glyphosate, Impact, Laudis, Liberty, Prowl, Status, Warrant, 2,4-D, and any pre-mix containing these ingredients.

 

Third Party Indemnified Reflex or Dual Magnum Labels for GA Vegetables (Culpepper)

Agents, I am getting a significant number of calls from growers regarding new Reflex and Dual Magnum vegetable labels.  Consider helping your growers by asking them to come in and visit with you to get their label. This is a great opportunity for young/new agents to obtain face time with our clientele!!

Agents MUST NOT give growers any indemnified label; however, agents can help them through the process but must make sure the grower clicks the “I ACCEPT” liability waver.

Obtaining the label for First Time:

1.  Go to www.farmassist.com

2.  Register the grower (or if you want a label register yourself); “register” is located on the 2nd tool bar in top middle of page.  After filling in information; click I accept at bottom.

: 

3.  The next page that pops up asks about you; you do not have to fill this out if you do not want.

4.  Select products along top bar.

6.  Select indemnified labels (4^th one down).

7.  For state, select Georgia and for product, select Dual Magnum or Reflex (play around and see our other labels) and then submit.

8.  Select the Dual Magnum or Reflex crop of interest and submit.

9.  Accept waiver; this is the process making the label an indemnified label.  GROWER MUST CLICK THE I ACCEPT KEY TO GET THEIR LABEL!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

10.  Print label and have present during application.

New Stuff for Field Corn (Prostko)

Just got word that a couple of new herbicides were registered for use in field corn.  Thought I would give you my take on their potential use in Georgia:

DiFlexx 4SC (Bayer):  DiFlexx is is a mixture of dicamba (DGA salt) and a crop safener (cyprosulfamide).  DiFlexx can be applied POST at 8-16 oz/A from the spike stage through the V6 stage or 36" tall which ever occurs first.  DiFlexx can be tank-mixed with glyphosate or Liberty.  Generally, dicamba is a good broadleaf herbicide but it has not been used very much in GA field corn for whatever reason.  I only have 1 field trial with this product so UGA data is very limited at this point. DiFlexx is not the same formulation of dicamba as the new cotton/soybean formulations (Roundup Xtend, Xtendimax, Engenia).  For a copy of the DiFlexx label, please refer to the following link:

http://www.cdms.net/LDat/ldC4D000.pdf


Revulin Q 51.2WDG (Dupont):  Revulin Q is a mixture of nicosulfuron (14.4%), mesotrione (36.8%), and a crop safener (isoxadifen).   Revulin Q @ 3.4-4 oz/A can be broadcast POST to field corn up to 20" tall or the V6 stage.  It can be tank-mixed with glyphosate, Liberty, or atrazine.  Revulin Q cannot be used if an OP insecticide was used in-furrow.  I have NO GA DATA for this herbicide at this point.  However, Revulin Q may have a good fit in GA since it would have some activity on Texas panicum.  For a copy of the Revulin Q label, please refer to the following link:

http://www.cdms.net/LDat/ldC5D000.pdf

On a different note, I have received several questions about the use of BASF's Sharpen 2.85SC herbicide for burndown use prior to planting field corn.  Here are a couple of things to consider:

1) I have minimal experience with Sharpen thus I do not feel comfortable recommending it.  Thus, neither should you!  I am concerned that some of our south GA soils may be too light.  Obviously, this would be less of a concern in North GA.

2) Sharpen is yet another PPO herbicide (i.e. same MOA as Spartan, Reflex, and Valor).  I have not been recommending PPO herbicides in field corn for obvious reasons. Field corn is the only major row crop grown in GA where a PPO herbicide is not really needed.

3) Some TN and Northern AL growers have been using Sharpen in combination with glyphosate to help control GR-horseweed.

4) 1-2 oz/A of Sharpen will cost somewhere between $5-10/A. For comparison, 1 pt/A of 2,4-D amine costs ~$1.50-2.00/A and 1 qt/A of atrazine costs ~$3.00-3.50/A.

For a copy of the Sharpen label, please refer to the following link:

http://www.cdms.net/LDat/ld99E000.pdf

Herbicide Injury Pictures (Prostko)

If you are looking for a few good resources to help diagnose potential herbicide injury problems, check out the following web-sites:

University of California - Davis (brand new as of January 2015)
http://herbicidesymptoms.ipm.ucanr.edu

Purdue University:
http://www.btny.purdue.edu/extension/weeds/herbinj2/injuryherb1.html

Kansas State University
http://www.ksre.k-state.edu/bookstore/pubs/c715.pdf

University of Missouri
http://weedscience.missouri.edu/herbinjsymptoms/

Some New Herbicide Formulations for 2015 (Prostko)

Here is the slate of new herbicide formulations that you might read or hear about somewhere.  I have indicated if I have any data on these products (Culpepper may have some as well) and whether or not they are included in my portions of the 2015 UGA Pest Control Handbook.  Generally, UGA weed scientists will not put any new products in the “official” recs until several site-years of data are collected. 

Company	Trade Name	Active Ingredients	Major Crops	Prostko Data	Recommended by UGA in 2015 (i.e. me)
ADAMA (formerly MANA)	Latir	Flumioxazin + imazethapyr	soybean	no	no
	Pummel	Metolachlor + imazethapyr	soybean	no	no
	Torment	Fomesafen +  imazethapyr	soybean	no	no
Bayer CropScience	Diflexx	Dicamba + cyprosulfamide	corn	yes	no
	Balance Bean	Isoxaflutole	soybean	no	no
Cheminova	Bestow	Rimsulfuron	corn	no	no
	Harrow	Rimsulfuron + thifensulfuron	corn	no	no
	Statement	Fomesafen + metolachlor	soybean	yes	yes
DowAgrosciences	Enlist Duo	Glyphosate + 2,4-D choline	corn/soybean	yes	no
Dupont	Afforia	Flumioxazin + thifensulfuron + tribenuron	soybean	no	no
	Revulin Q	Nicosulfuron + mesotrione+ isoxadifen	corn	no	no
FMC	Solstice	Mesotrione + fluthiacet	corn	no	no
Monsanto	Triple Flex II	Acetochlor + flumetsulam + clopyralid + furilazole	corn	no	no
	Rowel	Flumioxazin	cotton, corn, peanut, soybean	no	no
	Rowel FX	Flumioxazin + chlorimuron	soybean	no	no
NuFarm	Spitfire	Dicamba + 2,4-D ester	corn, soybean	yes	no
	Cheetah	Glufosinate	corn, soybean, cotton	no	no
	Cheetah Max	Glufosinate + fomesafen	cotton, soybean	no	no
Syngenta	Acuron	S-metolachlor + mesotrione + atrazine + bicyclopyrone	corn	yes	no
UPI	Broadloom	Bentazon	corn, peanut, soybean, sorghum,	no	no
	Satellite	Pendimethalin	corn, cotton, peanut, soybean	no	no
Valent	Fierce XLT	Flumioxazin + pyroxasulfone + chlorimuron	soybean	no	no

Avoid Early-Harvest-Aid Applications in Soybeans (Prostko)

Soybean growers with ants in their pants, who want to use paraquat as a harvest aid, should be warned not to apply too early.  Early applications (>40% seed moisture) will likely result in significant soybean yield loss as a result of reduced seed weights (Figure 1).  The 40% seed moisture content roughly coincides with the R6.5 to R7 stages of growth.  R6.5 = Full Seed = all normal pods on 4 uppermost nodes have pod cavities filled.  R7 = Beginning Maturity = one normal pod on main stem of all plants has reached mature color (Figure 2). Official UGA soybean harvest aid recommendations can be found on page 517 of the 2014 UGA Pest Management Handbook.

Figure 2.  Soybean Reproductive Growth Stages

Fierce Section 24(c) Label For Wheat in GA (Culpepper) - For County Agents Only!

Fierce, active ingredient pyroxasulfone and flumioxazin, just obtained approval for postemergence applications in Georgia wheat as a Section 24(c) Special Local Need Label. 

Valent and I have developed this use to help growers struggling with ryegrass that is resistant to postemergence herbicides.  Our intentions for the 2014/2015 crop are to have a controlled use of Fierce allowing Valent and UGA Cooperative Extension the chance to determine if the herbicide can be used to effectively manage problem weeds while having acceptable crop injury. 

Application of Fierce:

1.  Follow the label exactly; it is listed below.

2.  Wheat must be planted 0.75 to 1 inch deep and cannot be broadcast spread.

3.  Apply Fierce at 1.5 oz/A in ONLY water when wheat is between the spike and 2-leaf stage; ryegrass needs to be spike or smaller.

4.  Apply Fierce only in water.  Notice I just mentioned twice that you cannot have anything in the tank other than clean water and the herbicide; no exceptions so don’t even call and ask!

5.  Must use 10-15 GPA; prefer 15 GPA if weeds are emerged.

6.  Do not apply with airplane.

7.  Only for wheat!!  No need to ask about other grain crops at this time, only wheat.

On-Farm Evaluations:

Several agents have been contacted directly and asked to work with Valent conducting split field comparisons treating half the field with Fierce and half the field with the grower’s standard program to improve our knowledge.  If I have not contacted you but you have a burning desire to take a look, contact your local Valent salesman which should be one of the following: 

John Altom: 352-316-1366; David Yoder 850-377-8137; or Jerry Dowdy: 803-422-6605

Crop Injury:

1. Greatest potential for injury occurs when 1) label recommendations are not followed and 2) when open/cracked seed furrow allows herbicides to directly contact the seed, when seed are planted to shallow, or when seed are planted in a deep furrow that allows herbicide concentration after a rain/irrigation event while wheat is growing. 

2.  Even when following the label, injury will occur in some environments.  This is why we are taking such a conservative approach.  With that said, our research suggests the benefits in weed control far outweigh injury concerns when following the label; you guys need to tell us if the research is accurate or not.

3.  Strongly suggest growers only try a field or two; do not treat the farm!!!!

Limited Product:

1.  We believe there will be enough product to treat about 6000 acres which is limiting but exactly what we need for this season.