Soybean Harvest Aids, Classic/Florida Beggarweed/Peanuts (Prostko)

 1) A few comments about soybean harvest aids/desiccants:

a) General consensus among soybean specialists these days is to wait until R7 stage.

b) I have already written several blogs about this topic (https://ugaweedscience.blogspot.com/2024/08/soybean-desiccationharvest-aid.html)

c) A good/recent article from the University of Arkansas (https://arkansascrops.uada.edu/posts/harvest/soybean-harvest-aids-2025.aspx)

d) Soybean stages of growth

https://crops.extension.iastate.edu/encyclopedia/soybean-growth-stages

https://extension.msstate.edu/sites/default/files/publications/P4028_web.pdf

e) Check out Pages 266-267 in 2026 UGA Pest Control Handbook (https://fieldreport.caes.uga.edu/wp-content/uploads/2025/02/SB28-28.pdf)

2) Classic/Florida Beggarweed/Peanut:

a) I have been getting a ton of questions about the use of Classic for the late-season control control of Florida beggarweed in peanut.  "Control" is probably not a great word to use in this situation because in reality, late-season applications of Classic really do not provide "control" in the normal sense of the word but do help improve fungicide deposition and harvestabilty. 

b) Expectations for the success of Classic at this time are dependent on the size of the Florida beggarweed plants that get treated.  Simply, the bigger the plants, the less effective Classic will be.  I recently applied Classic + 2,4-DB to one of my peanut fields to get a better feel on what actually happens.  Basically, the Florida beggarweed plants were stopped in their tracks at the time of application.  What this means is that beggarweed plants that were at or slightly above the peanut canopy are now not effecting fungicide deposition.  But plants larger than this are.  The picture below is of 3 different Florida beggarweed plants in this field that illustrate this point.  So, if beggarweed plants are towering above the peanut canopy (Plant #3), probably not worth the effort/expense to apply Classic.  Here is what the Classic label says about Florida beggarweed control in peanut: "Apply before Florida beggarweed reaches 10" in height or begins to bloom".

c) For more information about the use of Classic in peanut, check out the 2026 UGA Pest Control Handbook, page 225 (https://fieldreport.caes.uga.edu/wp-content/uploads/2025/02/SB28-24.pdf)

d) Other options for Florida beggarweed control in peanut at this time of year include paraquat in a non-selective applicator (weed wiper, rope-wick), mowing, or hand-removal.

Palmer Amaranth, Drones, Drift, and Wild Poinsettia - Prostko

A few things you might find interesting:

1) Not a good idea to hand remove Palmer amaranth and drop in back on the ground.  It really needs to be removed from the field.

2) Just about everyone is in love with drones these days.  But, they have their issues.  We recently applied Glyphosate + Aim (carfentrazone) as a harvest-aid with a drone in one of our corn fields at the UGA Ponder Farm (08/06/26).  Look what happened (It was not very windy at all).  Sadly, I have seen too much off-target movement with drones.  Boom/application height, droplet size, speed, and situational awareness are so important!

 

3) Here is a closeup of the peanut injury from Glyphosate + Aim drift applied with a drone in field corn.

4) Here is what the morningglory looked like today after being treated with Glyphosate + Aim 8 days ago. Stems were still tough to chew.

5) I have suspected for a long time now that we might have ALS-resistance (Cadre, Strongarm) in some of our wild poinsettia populations in the counties that border Florida.  This poinsettia population was treated with Cadre by the grower then Jacob Kalina (Brooks Co.) and I followed up later with some Strongarm last week (08/05/26).  But, the wild poinsettia was a big as the peanuts at application? Looks like we might have to collect some seed for greenhouse testing? 

Late-Season Florida Beggarweed in Peanut (Prostko)

I have been getting a few calls/texts/e-mails about late-emerging Florida beggarweed in peanut fields, especially in fields that did not get a PRE application of Valor.

Figure 1.  Florida beggarweed in peanut.

Peanut growers have 2 options for the control of Florida beggarweed at this time of year.  The first is a POST application of Classic 25DG @ 0.5 oz/A + NIS @ 0.25% v/v.  Classic can be applied POST in peanut from 60 days after emergence (DAE) until 45 days before harvest.  The latest update that I have in regards to variety tolerance to Classic is as follows:  Classic should NOT be used on GA-06G and Tifguard due to potential yield losses (7-11%).  The following peanut varieties have demonstrated adequate tolerance to Classic in UGA replicated/weed-free field trials: Florida-07; GA-Greener; GA-07W; GA-18RU; AUNPL-17; TIFNV High O/L; GA-20VHO; and FloRun™ 331. For GA-09B, peanut yields were reduced by 5% when applied 75 DAE but no yield loss occurred when applied 60, 90, or 105 DAE.  For GA-16HO, peanut yields were reduced by 13% when Classic was applied at 70 DAE, but no yield loss occurred when applied at 60 DAE or 85 DAE.  For GA-12Y, peanut yields were reduced 8% when Classic was applied 60 DAE but not at 70 DAE or 85 DAE.  For TifNV-HG, Classic had no effect on peanut yield when applied 64 DAE or 74 DAE (only 1 year of data but repeating in 2026). 

The second option that peanut growers have for later emerging Florida beggarweed in peanut is to use a 33% solution of Gramoxone 3SL (paraquat) in a non-selective applicator (NSA). Based upon field trials conducted many moons ago in Georgia, the following NSA's were more effective:

 

Figure 2.  GrassWorks WeedWiper
(https://grassworksmanufacturing.com/)

Figure 3.  TopCrop Super Sponge
(https://www.topcropaginnovations.com/)

Figure 4.  LMC-Cross Wick Bar
(no longer available)

For additional information about the use of Classic or Gramoxone for the late-season control of Florida beggarweed in peanut, check out page 225 in the 2026 UGA Pest Control Handbook-Volume I.

Peanut Pics (Prostko)

A few pictures from my research plots this week that I thought you might find interesting: 

1) Here is a recent picture of the tractor/drone weed control study I am working on with Dr. Wes Porter. I have to admit I have been very surprised at the efficacy with reduced GPA's. We treated yesterday morning with a combination of Trizenta (clethodim) @ 10 oz/A + Dual Magnum @ 16 oz/A.

2) Possible leaf injury from a tank-mix of Excalia @ 4 oz/A + Chlorothalonil @ 16 oz/A (8 DAT)? Applied 42 DAP to TifNV-HG.

3) 2,4-DB injury. This type of injury does not show up 100% of the time after an application of 2,4-DB.

4) Peanut leaf injury from a Provost Silver @ 13 oz/A + Dual Magnum @ 16 oz/A tank-mix.

Peanut Weed Control Update (Prostko)

 1) A few pictures from my peanut weed control plots taken earlier today. Further proof that UGA recommended programs work when applied in a timely manner.  

2) Growers who do not like Sonalan can use Prowl.  Growers who do not like Dual Magnum can use one of the following: Anthem Flex, Enversa, Outlook, Warrant, Zidua.  Growers who do not like Basagran can use Storm or make their own "Georgia Storm" (Ultra Blazer @ 16 oz/A + Basagran 5SL @ 6.4 oz/A).  Growers who do not like Cobra can use Ultra Blazer. Growers who do not want to use Cadre are likely to see less control of sicklepod and nutsedge (sorry but that's the truth!).

3) For growers who did not get their PRE herbicides applied, there is hope!

4) I have heard thru the grapevine that Ultra Blazer is short or non-existent in GA at this time. I have also heard that there was about 11,000 gallons of Cobra in a Valdosta warehouse last week.  So growers who are told that there is no Cobra, need to think about shopping elsewhere!

5) I have been getting lots of questions about Benghal dayflower.  It thrives in wet weather! Also, Benghal dayflower will be worse in peanut fields planted after May 15 and into June. The key to controlling this weed is moisture activated residual herbicides (Group 15's).  I have no preference but we do have more data with Dual Magnum simply because the other Group 15 herbicides (Anthem Flex, Enversa, Warrant, and Zidua) were not on the market way back then.  Outlook has been around for awhile but was always the Group 15 red-headed step child for various reasons until recently (labeled for peanut in 1999).

Questions and Answers from Today: Field Corn, Grain Sorghum, Soybean, Peanut (Prostko):

This morning was an interesting day for various weed science related questions on multiple crops (field corn, sorghum, soybean, peanut).  Since most questions are common to all (sooner or later), I thought I would share:

Question#1: How much Dual on Concep treated sorghum would it take before you would start seeing damage? 

Answer#1: Probably would need to be above 2.5 pts/A on our soil types before you would start seeing significant injury.  Research from Kansas State University a few years ago would suggest that what would be the equivalent of 4 lb ai/A of Dual Magnum (4.2 pts/A) did not cause major yield losses when Concep treated sorghum seed was planted.  

Check out this 1992 publication from Kansas State University:

https://extension.k-state.edu/historicpublications/pubs/SB659.pdf

Dual Injury Pictures on grain sorghum:

Figure 1.  Dual injury on grain sorghum (https://grdc.com.au/__data/assets/pdf_file/0029/627914/avoid-metolachlor-damage-in-sorghum-grdc-20251003.pdf)

Question#2: Is this herbicide injury on field corn?

Figure 2.  Magnesium deficiency on corn (A. Smith)

Answer#2: No, this is not herbicide injury. Most likely a magnesium deficiency which can be confirmed via a leaf tissue test.

Question#3: I have a peanut field that rain kept us from spraying behind planter.  No herbicides have been applied. What do you suggest?

Answer#3: If peanuts are less than 28 days after cracking:  Gramoxone 3SL @ 8 oz/A + Ultra Blazer 2SL @ 16 oz/A + Basagran 4LC @ 8 oz/A + Zidua 4.17SC @ 2.5 oz/A or Anthem Flex 4SE @ 3 oz/A + NIS @ 32 oz/100 gals (0.25% v/v).  Zidua or Anthem Flex would be preferred in this situation because they both contain pyroxasulfone which is slightly better on Texas panicum than the other Group 15 herbicides (Dual Magnum, Enversa, Outlook, Warrant) and neither Prowl nor Sonalan was applied.

Question#4: Can I apply Prowl over the top of soybeans (V5) at 16 oz/A?  

Answer#4:  Prowl is NOT labeled for postemergence (POST) use in soybean. When applied POST, I have seen it cause galling at the soil surface which can result in stem breakage later in the year.  NO Bueno!  Group 15 herbicides can be used.    

Question#5:  I have peanuts that are now 33 DAP that have mostly nutgrass but some escaped pigweeds and sicklepod.  I am assuming the pigweeds are ALS-resistant but they are 2-3" tall while nutgrass is pretty thick in places.  Would it not be best to spray Cadre + 2,4-DB + Dual and hope the 2,4-DB takes out the small pigweed?  I don't want the nutgrass taking over.

Answer#5: 2,4-DB is not very effective for pigweed control when tank-mixed with Cadre but it does help with other weeds such as sicklepod and morningglory.  In this case, I would suggest the following:  Cadre 2SL @ 4 oz/A + Cobra 2EC @ 12.5 oz/A or Ultra Blazer 2SL @ 24 oz/A + Dual Magnum 7.62EC @ 16 oz/A + 2,4-DB 2SL @ 16 oz/A.  Other Group 15 herbicides (Enversa, Outlook, Warrant, Zidua) can be used in place of Dual Magnum if desired.

Question#6:  Can I use Basagran + Dual Magnum for Benghal dayflower/tropical spiderwort control in peanut and should I add a crop oil to this mixture?

Answer#6:  Yes, Basagran 4LC @ 32 oz/A + Dual Magnum 7.62EC @ 16 oz/A is a very effective treatment for dayflower species.  Additional crop oil is not needed because the Dual Magnum is an EC (oil-based) formulation and has adjuvant-like properties.  

Figure 3.  Spreading dayflower control in peanut with Broadloom (generic Basagran) and Dual Magnum with no additional COC.

"Cracking" Time Tips for Peanuts (Prostko)

Many peanut growers are likely to begin or already have begun treating their fields with early-postemergence ("cracking") applications of Gramoxone (paraquat).  Here are a few tips for success as well as some pictures from "cracking" treatments that I applied just last week:

1) Cracking applications can be applied from peanut emergence up until 28 days after cracking. Cosmetic injury (stunting and leaf necrosis) should be expected.  Generally, this injury will not result in peanut yield loss as long as the label is followed (i.e. application rate and time).  Here is the Gramoxone label for those that might (should) be interested:

https://s3-us-west-1.amazonaws.com/agrian-cg-fs1-production/pdfs/ Gramoxone_SL _3.0 _Label1de.pdf

2) 15 GPA and coarse droplets (VMD₅₀ ≥ 270 microns) are preferred. Gramoxone is NOT LABELED for aerial applications when applied postemergence in peanuts.

3) The UGA recommended treatment (without walking the field) is as follows:  Gramoxone 3SL @ 8 oz/A + Storm 4SL @ 16 oz/A + 1 Group 15 herbicide (either Anthem Flex 4SE @ 3 oz/A or Dual Magnum 7.62EC @ 16 oz/A or Enversa 3ME @ 48 oz/A or Outlook 6EC @ 10.5 oz/A or Warrant 3ME @ 48 oz/A or Zidua 4.17SC @ 2.5 oz/A). I do not have a Group 15 preference.  Anthem Flex will cause more cosmetic injury due to one of its active ingredients (carfentrazone, trade name: Aim).

4) NIS @ 0.25% v/v (32 oz/100 gals) should be included except when Dual Magnum or Outlook are used. Both of these herbicides are EC formulations (oil-based) and therefore have adjuvant-like properties.

5) Growers can make their own Storm (aka "Georgia" Storm) by tank-mixing Ultra Blazer 2SL @ 16 oz/A + either Basagran 4SL @ 8 oz/A or Basagran 5SL @ 6.4 oz/A.  This is a more appropriate ratio for south Georgia and also will be slightly cheaper.  

6) Gramoxone mixing order (from label):

4.4.3 GRAMOXONE SL 3.0 IN TANK MIXTURES: 1. Fill spray tank 1/2 full with clean water or other approved carriers such as clear liquid fertilizer. 2. Add nonionic surfactant to tank 3. Begin tank agitation and continue throughout mixing and spraying. 4. Add dry formulations (WP, DF, etc.) to tank. 5. Add liquid formulations (SC, EC, L, etc.) to tank. 6. Add Gramoxone SL 3.0 to tank. 7. Add crop oil concentrate or methylated seed oil to tank where/if needed. 8. Fill remainder of spray tank

7) Some field pictures from earlier today.  Treatments were applied 4 days ago: