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.

Wet Weather and Peanuts - 2024 (Prostko)

1)The current rainfall event that is occurring in many parts of Georgia will likely result in Valor (flumioxazin) injury in some peanut fields.  I do not feel they need to reinvent the wheel, so please check out the following previous 6 blogs where I have addressed the Valor/peanut injury issue: 

June 3, 2013: https://ugaweedscience.blogspot.com/2013/06/valor-injury-on-peanut-prostko.html

May 20, 2014: https://ugaweedscience.blogspot.com/2014/05/peanut-injury-update-prostko.html

May 26, 2017: https://ugaweedscience.blogspot.com/2017/05/valor-injury-or-sky-is-falling-prostko.html

May 21, 2020: https://ugaweedscience.blogspot.com/2020/05/valor-injury-on-peanut-is-likely-prostko.html

May 23, 2021:https://ugaweedscience.blogspot.com/2021/05/irrigating-peanut-fields-treated-with.html

May 13, 2023: https://ugaweedscience.blogspot.com/2023/05/valorpeanut-injury-again-prostko.html

TAKE HOME POINT FOR THE VALOR/PEANUT INJURY ISSUE: VALOR INJURY IS LIKELY BUT YIELD LOSS IN NOT!

2) Peanut growers who have missed the recommended application timing for applying Valor + Strongarm + Prowl or Sonalan (PRE) should not panic.  My suggestion would be to let the peanuts emerge, then treat herbicide "naked" fields with an EPOST application of Gramoxone + Storm or Basagran + Zidua or Anthem Flex + NIS (Page 221 of 2024 UGA Pest Control Handbook).  I usually do not have a preference between the Group 15 herbicides (Anthem Flex, Dual Magnum, Outlook, Warrant, Zidua).  However in fields that were not treated with any Prowl or Sonalan, I do prefer Anthem Flex or Zidua in the first EPOST treatment because these herbicides provide slightly better control of Texas panicum (i.e. bullgrass or buffalograss).  Check out the picture below from my 2023 research plots.  No PRE herbicides were applied (on purpose) but I was still able to obtain very effective weed control.  This situation is not ideal but growers can make it work.    

Liberty + Roundup/Paraquat + Diuron + Fomesafen (Prostko)

A few things to chew on: 

1) I have gotten many questions about tank-mixing Roundup + Liberty for weed control in field corn.  Check out this picture from my 2024 plots (May 6).  No real difference in weed control between 22 oz/A or 27 oz/A or 32 oz/A of Roundup + Liberty (tank-mixed with Atrazine and Prowl).  Field corn looks a little ratty because the farm received 0.9" of rain on May 4 and some hail.

2) Justin Hand (Tift Co. Agent) and I just got back from trying to help a grower figure out a tank-mixing problem he was having with NIS + diuron + fomesafen + paraquat.  Turns out that the problem was related to the diuron formulation.  No problems with the Direx (Adama) formulation (left) but a significant problem with the Diuron (Drexel) formulation (right).  

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Halex GT Mixing Problem in Corn/Valor Applied PPI (Prostko)

 A couple of things to bring to your attention based upon my week:

1) A field corn grower in Macon Co. experienced a significant problem when Halex GT (mesotrione + S-metolachlor + glyphosate-K salt) was tank-mixed with a different type of glyphosate formulation (IPA salt) (Figure 1).  This problem did not occur when other K salt formulations (Roundup PowerMax3 or Honcho K6) were used (Figure 2). Remember that all glyphosate formulations are not created equal.  They have different concentrations of active ingredients, are formulated as different salts (K, IPA, DMA), and may/may not be formulated with adjuvants. In my April 8 blog, I provided you with a couple of links where you can get some handy information (charts) about the different glyphosate formulations.

Figure 1.  Halex GT tank-mixing problem in Macon County, 2024.

Figure 2.  Different glyphosate formulations tank-mixed with Halex GT + Atrazine +
Mustang Max + NIS + Defoamer

2) Please remind your growers that UGA does not recommend that Valor be applied pre-plant incorporated (PPI) for weed control in peanut!  Valor is not labeled for that type of application and pigweed control will be significantly reduced (PPI is 25-35% less effective than when applied PRE behind the planter).   

 

Figure 3.  Palmer amaranth control in peanut with Valor applied PPI or PRE.

Wet Weather and PRE Herbicides (Prostko)

In the last 2 days, many locations in south Georgia received lots of rain (Figure 1).  Thus, I have been getting many texts and telephone calls about what might happen to any PRE herbicides that were applied to field corn.  In general, I would say that if runoff/washing was minimal, there is a good chance that the herbicides are still in the field, especially if the PRE treatments were watered in soon after application.  Research in Georgia has shown that runoff of Dual II Magnum and Prowl EC in conventional tillage systems was reduced 1.2-2X when irrigation occurred shortly after application (Potter et al. 2008.  Herbicide incorporation by irrigation and tillage impact on runoff loss.  Journal of Environmental Quality 37:839-847).

In 2022, a very similar weather event occurred in my research plots during the first 7 days after planting (3.84" of irrigation/rainfall).  All my PRE herbicides worked just fine (Figures 2, 3, 4).  Note in Figure 2 that there are some wild radish plants in the plot but no pigweed or grasses.  In general, all of the Group 15 herbicides (Anthem Maxx, Dual Magnum, Outlook, Warrant, Zidua) do not provide adequate residual control of wild radish so this should not be a surprise.  FYI, Anthem Maxx/Zidua are slightly better on wild radish than the other Group 15's.

Bottom line, no way to know for certain how much herbicide will be left in the field.  My best advice would be to keep eyes on/feet in the field and pull the trigger earlier on POST treatments when/if needed.  

Figure .  South Georgia Rainfall, April 10-11, 2024.

Figure 2.  Weed control with Everprex in a rainy year.

Figure 3.  Weed control with Acuron in a rainy year.


Figure 4.  Weed control with Maverick in a rainy year.