Strongarm/Cadre/Cobra - Prostko

 A few quick comments based upon texts, e-mails, and phone calls this week:

1) Clethodim + Strongarm + Crop Oil + AMS Tank-Mixes????  Nothing better than good data.  See chart below.  Anywhere from 0% to 17% less grass control when Strongarm was mixed with Select.  You may recall that grass control is often reduced when POST grass herbicides are tank-mixed with certain fungicides and herbicides (i.e. antagonism).  Antagonism can be avoided by applying the POST grass herbicide first then applying the other agri-chemicals ~3 days later.

2) Cadre Programs?  Check out this picture from my peanut plots earlier this morning.  Further proof of the need for Cobra (or Ultra Blazer) + any Group 15 herbicide (Dual Magnum, Outlook, Warrant, Zidua) applied in combination with Cadre + 2,4-DB.  Most or all of the Palmer amaranth populations in Georgia have some level of resistance to the ALS-inhibiting herbicides.  

3) Is there a Cobra shortage?  According to my contacts as Valent, there are about 20,000 gallons of Cobra sitting in a warehouse in Albany, GA.  My contacts at Triangle tell me there is at least 1 pallet (180 gallons) of Cobra at their facility in Leesburg.  Not sure why some dealers are reluctant to procure some Cobra?????

4) My schedule over the next few weeks:

a) July 8-July 11: APRES (Oklahoma City, OK).  Still available via e-mail, phone, text, smoke signal, 24/7.  

b) July 12-21: I will be on vacation.  Please try to reach me via e-mail. I will be looking at my e-mails at least once/day in the early AM.  If you have an emergency (i.e. a WTF moment), shoot me a text and I will try to call you back ASAP.  Herbicide application rates, timings, rain-free periods, PHI, etc. are NOT an emergency.  All of this type of information can be found in 2024 UGA Pest Control Handbook.  However, more than happy to take those types of questions when I am in town.        

Cadre (imazapic) Review - Prostko

Lately, I have been getting a lot of calls about the use of Cadre (imazapic) in peanut.  Since we have many new county extension agents and us old folks have fading memories, I thought it might be a good time for a quick review.  Here are 10 things about Cadre you may or may not have known.   

1) The active ingredient in Cadre was first discovered in 1981 by American Cyanamid Company.  

2) Cadre was first registered for use in peanut in 1996.

3) Cadre was tested under the code number AC-263,222.  Much of the foundation research on AC-263,222 was conducted in Georgia [Drs. John Wilcut (former VT, UGA and NCSU Research Weed Scientist) and John Richburg (Corteva)].

4) Cadre was first formulated as a 70DG but is now sold a 2AS.

5) Although most peanut growers usually apply Cadre around 30-45 days after planting (DAP), it can be applied earlier.  Peanuts have excellent tolerance to Cadre.  Check out this older Georgia yield data. 

6) In some other countries (i.e. Australia), imazapic is applied preemergence (PRE).  Cadre is not labeled for PRE applications in Georgia peanuts because PRE applications are more likely to result in cotton carryover problems (and other sensitive crops) and also can be less effective on Florida beggarweed.

7) Cadre can occasionally cause "yellow flash" injury when used in peanut.

8) ALS-resistant Palmer amaranth was first confirmed in Georgia in 2000 after collecting seed from a peanut field where Cadre treated plants survived the application.

9) ALS-resistance in yellow nutsedge was confirmed in Georgia in 2021.  In this field, peanuts were grown continuously for 4 years where ~18 oz/A of  Cadre was applied during that time period.  Not the normal use pattern or rotation sequence for most of Georgia.     

10) Imazapic is sold under many trade names including Impose, Plateau, and Comrade.

"Georgia" Storm for Peanut/Soybean Tank-Mixes (Prostko)

1) Since the agent training in Tifton on June 6, I have had numerous questions about the "Georgia" Storm that I talked about in peanuts.  The commercial formulation of Storm 4SL from UPL is a pre-mixture (i.e. 1 jug) of acifluorfen (1.33 lbs ai/gal) + bentazon (2.67 lbs ai/gal).  The normal recommended use rate (by me) of commercial Storm is 16 oz/A when combined with Gramoxone (paraquat) in an early-post or "cracking" spray.  Storm @ 16 oz/A is equivalent to rates of ~11 oz/A of Ultra Blazer 2LC (acifluorfen) + ~11 oz/A of Basagran/Broadloom 4LC (bentazon). In my opinion, 11 oz/A of Basagran/Broadloom is sometimes too much in this mix.  At this rate, Basagran/Broadloom will reduce peanut leaf burn but could also reduce efficacy on some weeds in certain scenarios (i.e. larger Florida beggarweed and sicklepod). 

I use the term "Georgia" Storm when growers choose to make their own by tank-mixing Ultra Blazer 2LC @ 16 oz/A and Basagran/Broadloom 4LC @ 8 oz/A (i.e. 2 separate jugs).  These application rates are more ideal for the general weed complex that growers have in most Georgia peanut fields.  Based upon some recent price estimates, "Georgia" Storm is ~$1.75/A cheaper than the commercial Storm.  But, many growers prefer the convenience of only having to deal with 1 jug. Both Storm and "Georgia" Storm have performed very well in my 2024 research plots.  See below.    

    

2) I have had a a bunch of questions about the following tank-mixes in soybean.  When I was conducting my original on-farm tropical spiderwort research in the early 2000's, Liberty-Link soybeans were not yet commercialized (2009) and dicamba-tolerant soybeans were a pipe dream. Please note that Basagran is not labeled for use in combination with Engenia according to the latest tank-mix information (https://www.engeniaherbicide.com/tank-mix.html).  However, Basagran is labeled for use with Xtendimax (https://www.xtendimaxapplicationrequirements.com/#/intro).

Cadre Time in Peanut (Prostko)

Peanut growers should be seriously thinking about beginning their POST herbicide applications as early as 30 DAP.  Some peanut growers will choose to use Cadre (imazapic).  Others may not want to use Cadre due to crop rotation/carryover concerns.  Here are a few things to consider:

1) Growers who will be using Cadre need to consider the fact that much of the Palmer amaranth in Georgia is resistant to the ALS-inhibiting herbicides.  Thus, it's a a a good idea to tank-mix Cobra (lactofen) or Ultra Blazer (acifluorfen) with Cadre to address this particular issue. If Cobra or Ultra Blazer are not included, it will be too late to control those pigweeds once a grower discovers that they are ALS-resistant.  

2) If a grower cannot use Cadre, then Cobra or Ultra Blazer are the best options for pigweed.  When pigweed plants are small (2"-4"), there is not much difference in control between Cobra or Ultra Blazer.  However, Cobra is more effective on larger weeds (>4").  But, Cobra will cost about ~$9/A more than Ultra Blazer.  It is important to remind growers that if Cadre is not used in peanut, it is very likely that yellow/purple nutsedge and sicklepod/coffeeweed will be a problem.  

3) If sicklepod is also present in the field, Butyrac (2,4-DB) should be included in the tank-mix. I recently heard from a grower in Middle Georgia that there was a rumor floating around that I only recommended 12 oz/A of 2,4-DB in peanuts.  To set the record straight, I recommend the use of 12 oz/A of 2,4-DB, if needed, when it is tank-mixed with Gramoxone (paraquat) + Storm (bentazon + acifluorfen) + Group 15 when applied early-postemergence (i.e. cracking spray).  I usually recommend 16-24 oz/A of 2,4-DB when it is applied POST with Cadre or Cobra or Ultra Blazer.  

4) Because pigweed and annual grasses are such a problem in most peanut fields, it's also a good idea to think abut including a Group 15 herbicide that will provide additional residual control of these weeds.  Group 15 herbicides include the following: Dual Magnum (S-metolachlor), Outlook (dimethenamid-P), Warrant (acetochlor), and Zidua (pyroxasulfone).  Not much difference in weed control between the Group 15 herbicides but Zidua has provided slightly better residual control of Texas panicum in my research trials over the years.

5) When Dual Magnum or Outlook are included in POST tank-mixtures, additional adjuvants are not recommended because these are EC (emulsifiable concentrates i.e. oil-based) formulations.  NIS (0.25% v/v) is recommended if any of the other Group 15 herbicides are used since they are not EC formulations. 

6) Check out Figure 1 below.  These pictures were taken from my plots on June 3, 2024.   Since the Palmer amaranth population at this location is ALS-resistant, I am getting much better control with the Cadre + Cobra or Ultra Blazer tank-mixes. 

7) Note that I have included the estimated prices/A for each of these treatments.  These are average prices that I have obtained from several dealers so they will very likely be slightly different for every grower.   

  

Figure 1.  Weed control in peanut with Cadre/Cobra/Ultra Blazer/2,4-DB/Dual Magnum tank-mixtures in peanut, UGA Ponder Research Farm, Ty Ty, GA, June 3, 2024.