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:

 

Crying Wolf with Valor? (Prostko)

Not sure what's going over the last few days in the peanut patch but I have received numerous inquires about Valor applications ahead of the anticipated rainfall over the next few days.  Here are some reminders to share with overly concerned growers:

1) I have been working with Valor since 1997.  Since that time, I have NO data that proves that when injury occurs, peanut yields are significantly reduced after a labeled/recommended application (3 oz/A within 48 hours after planting, at least 1.5" planting depth).

2) Valor does NOT effect peanut seed germination and radical development.  Recent UGA thermogradient studies indicated that when there is direct peanut seed exposure to Valor at field application rates, there in NO impact on germination and radicle development (Source: Peanut Science (2020) 47:89-93).

3) From 2017-2019, I conducted field trials to evaluate the potential effects of high moisture conditions on peanut response to Valor.  During those trials, peanuts were exposed to 8.0-11.3" of rainfall/irrigation in the first 30 DAP.  Yields were NOT reduced in any year (Source: Peanut Science (2021) 48:113-117). Here is some data for the "Doubting Thomas": 

Figure 1. Peanut yield response to Valor under high moisture conditions in 2018 (UGA Ponder Farm, Ty Ty).  Peanuts were planted 2" deep and Valor was applied 48 hours after planting.  3 oz/A is the labeled and recommended use rate.  

4) Peanuts are most likely to be injured by Valor when higher rates are applied, applications are delayed past 48 hours after planting, peanuts are planted too shallow, and heavy rainfall occurs as the peanuts begin to emerge (i.e. cracking).  Irrigation immediately after application will not prevent Valor injury when heavy rainfall events occur at cracking.

5) Here is an injury picture from some work I did way back in 2009.  Pretty bad but NO yield loss!

Figure 2.  Valor injury 17 DAP (Attapulgus, 2009).  5.44" total rainfall from 

planting until picture was taken. Valor was applied the same day as planting, 

1.75"  planting depth.  

Drought/Dryland Peanuts/Herbicides (Prostko)

No doubt the current drought conditions are on everyone's mind.  Thus, I have been getting tons of inquiries on how to manage herbicides in this situation, especially dryland fields.  I don't have all the answers but here are a few thoughts:

1) Residual herbicides must have moisture to be "activated".  Activation simply means the movement of the herbicide into the upper 1"-2" of soil. This is the depth where most annual weeds emerge from.  Moisture is also needed to keep the herbicide in the soil solution so that it can be absorbed into germinating weed roots and shoots.  

2) In dry conditions, mechanical incorporation will improve the chances for success of some residual herbicides but is not a 100% guarantee under extreme drought conditions.  In a drought, herbicides such as Prowl or Sonalan can be more tightly adsorbed onto soil colloids which makes them less available for plant uptake. If a grower is mechanically incorporating a herbicide and he cannot see the implement behind him because of the dust cloud, its very doubtful that incorporation will matter.

3) Since most residual herbicides only last on the ground for about 7-10 days (~14-17 days for Valor) before they must be moisture activated, it might be a good idea in dryland fields to go "naked" (no PRE) at planting. Wishing/hoping that more reliable rainfall is in the future?  It costs roughly $20-23/A for the UGA standard PRE program of either Prowl or Sonalan (32 oz/A) + Strongarm (0.225 oz/A) + Valor (3 oz/A).  So if it does not rain and these fail to perform, that's good money lost! 

4) A strong "naked" weed control program would include an "AT-CRACKING/EPOST" application of Gramoxone + Storm (brand name or home-made) + a Group 15 herbicide (Anthem Flex, Dual Magnum, Enversa, Outlook, Warrant, or Zidua: FYI, I have no preference here) followed by a timely "POST" application of Cadre + Cobra + 2,4-DB + Group 15.  But, a grower must be ready to pull the trigger in these fields that have no PRE. There can be no delay!!

Figure 1.  "Naked" (no PRE) program for dryland peanuts.  Group 15 herbicides that can be used here include Anthem Flex, Dual Magnum, Enversa, Outlook, Warrant, and Zidua.

5) I do believe that since Valor does last a little longer without moisture activation and is super cheap (~$1/oz), that it might be worth the risk (cheap insurance)?  

Preplant Burndowns for Peanut (Prostko)

I have been getting a few calls about preplant burndown options for strip-till peanut fields.  They say a picture is worth a 1000 words so see below for a few options.  As a reminder, the plant-back restriction for peanut after 2,4-D is 7 days and 0 days (1 oz/A) or 7 days (2 oz/A) for Reviton.  Also, remember that Reviton has no soil residual activity.

Figure 1.  Preplant burndown with Roundup PowerMax3 + 2,4-D amine + Valor EZ, March 27, 2026 (7 DAT), UGA Ponder Farm.

Figure 2. Preplant burndown with Roundup PowerMax3 + Reviton, March 27, 2026 (7 DAT), UGA Ponder Farm.

Droplet Sizes for Contact POST Herbicides (Prostko)

When visiting with your growers, please remind them to use a nozzle/pressure combination that produces COARSE droplets (VMD₅₀ = ≥ 270 microns) when applying contact herbicides such as Basagran (bentazon), Cobra (lactofen), Gramoxone (paraquat), Liberty (glufosinate), and Reflex (fomesafen).  COARSE droplets provide a reasonable balance of drift protection and coverage.  Droplets larger than coarse provide better drift protection but less coverage. Coverage is extremely important for contact herbicides especially when application conditions are not favorable (large weeds, cold temperatures, drought). Various nozzle types and pressures can be used to obtain COARSE droplet sizes (green color on TeeJet chart listed below).

Not playing favorites here with this TeeJet chart but a recent UGA Extension survey indicated that 68% of Georgia farmers use TeeJet nozzles. Other nozzle purveyors include the following:

Greenleaf Technologies: https://greenleaftech.com/

Pentair Hypro: https://www.pentair.com/en-us/flow/hypro/hypro-products/hypro-spraying-products/hypro-spray-nozzles.html

John Deere: https://cdn.prod.website-files.com/66e9e33a09ceaffe3ed4b8dd/66fef97547cff80b92845bf6_JD-Sprayer-Parts-Catalog-2019.pdf

Paraquat Trainings (Prostko)

Since Syngenta recently announced that they will no longer be manufacturing the active ingredient paraquat (https://www.syngenta.com/media/syngenta-cease-paraquat-production-uk-2026), I have received numerous inquires about the future of the US EPA required paraquat safety trainings (https://www.epa.gov/pesticide-worker-safety/paraquat-dichloride-training-certified-applicators#q4).  The following is information that I received from Syngenta on March 13 regarding the issue of paraquat safety training:  

"Syngenta will continue to provide paraquat training via its online training portal while channel inventories of Gramoxone® Herbicide still exist. Our commitment to stewardship, safe use, and regulatory compliance remains unchanged, and we recognize how essential this training is for certified applicators across the country.

 

As we look ahead, Syngenta is actively evaluating options to transition the paraquat training program to an alternative host to ensure continuity beyond our direct involvement. We will share updates as soon as a viable path is confirmed.

 

Thank you for your continued dedication to safe and responsible pesticide application. If you need assistance accessing the training, please reach out to your Syngenta representative or visit the paraquat training portal.  Gramoxone Herbicide is a Restricted Use Pesticide.  Always read and follow label instructions."

Dicamba Preplant in Field Corn (Prostko)

It has come to my attention that the recommendations for preplant/burndown applications of dicamba for field corn in the UGA Pest Control Handbook are NOT sufficiently described.  After closer review of the product labels, there needs to be some adjustment.  Please review the following with any grower who desires to use dicamba for preplant/burndown weed control prior to planting field corn.

1) The newer formulations of dicamba (Stryax®, Engenia®) are NOT labeled for this particular use.

2) Older formulations of dicamba (Clarity®, Rifle®, Sterling Blue®) are labeled for this use depending upon tillage system and soil type as follows:

a) PREPLANT AND PREEMERGENCE APPLICATION IN NO TILLAGE CORN: Rates: Apply 16 fluid ounces of Clarity®, or Rifle®, or Sterling Blue® per acre on medium-or fine-textured soils containing 2.5% or greater organic matter. Use 8 fluid ounces per acre on coarse soils (sand, loamy sand, and sandy loam) or medium-and fine-textured soils with less than 2.5% organic matter.  

b) PREEMERGENCE APPLICATION IN CONVENTIONAL OR REDUCED TILLAGE CORN: Rates: Apply 16 fluid ounces of Clarity®, or Rifle® or Sterling Blue® per treated acre to medium- or fine-textured soils that contain 2.5% organic matter or more. DO NOT apply to coarse-textured soils (sand, loamy sand, or sandy loam) or any soil with less than 2.5% organic matter until after corn emergence.  

c) Failure to follow these recommendations could result in excessive crop injury.  If a grower applies dicamba as a burndown in a field intended to be planted to dicamba-tolerant cotton or soybean and changes their mind and wants to plant field corn, please contact me ASAP. 

3) Everyone always asks me what my preferred burndown is for field corn.  Lots of good choices.  But, I prefer Roundup or Gramoxone + atrazine because these combos will control most of our common winter weeds and field corn can be planted immediately without concern for crop injury.  See below.

Ryegrass Control in Conventional Field Corn (Prostko)

Lucy Ray from Morgan County recently asked me about ryegrass control in conventional field corn.  Here are my thoughts:

1.  I contacted several local GA corn seed reps to see what conventional hybrids with tolerance to ALS-inhibiting herbicides would be recommended in Georgia.  The short list is as follows: Dekalb 68-37 or 66-02 or 111-30; Integra 6588; Dyna-Gro 57CC51; Pioneer 1608 or 17677; and AgriGold A645-16.
2. Ryegrass is extremely difficult to control in conventional corn.  Expectations should be fair/marginal at best. NO miracles here!
3. Three postemergence herbicides are available for use in conventional corn that have some activity on ryegrass (again not great but all we got).  These include Accent Q (nicosulfuron), Revulin Q (nicosulfuron + mesotrione), and Steadfast Q (nicosulfuron + rimsulfuron).  These herbicides cannot be used if Counter is applied in-furrow for soil insect/nematode management.  
4. My suggested weed control program for this scenario would be as follows (reduced tillage/strip tillage): 

1. Prior to planting, if ryegrass and other winter weeds are emerged, split shot of Gramoxone 3SL (paraquat) @ 32 oz/A (~10 days apart) + COC @ 1% v/v (1 gal/100 gal). In the second shot, add Dual II Magnum 7.64EC (S-metolachlor) @ 16 oz/A for residual control of annual grasses and broadleaf weeds.  This second shot of Gramoxone + Dual II can be applied before or after planting (but before corn emergence).  The goal here is to start off as clean as possible.
2. At V3-V5 stage of corn, apply either Accent Q 54.5WDG @ 0.9 oz/A or Steadfast Q 37.7WDG @ 1.5 oz/A or Revulin Q 51.2DF @ 3.5 oz/A + Atrazine 4L @ 64 oz/A + NIS @ 0.25% v/v (1 qt/100 gals).  Remember these are not great (for ryegrass/crabgrass) but all we have for POST grass control in conventional corn.  

    5)  FYI, ryegrass is one of many weeds that does not like deep tillage (i.e. turning plow).

Positive Pesticide Points (Prostko)

It's not too often that the general public hears any positive information about the safe use of pesticides in agriculture. In 1991, the U.S. Department of Agriculture (USDA) Agricultural Marketing Service (AMS) was charged with designing and implementing the Pesticide Data Program (PDP) to collect data on pesticide residues in food. Congress mandated the program in the 1996 Food Quality Protection Act (FQPA). The results of the 2024 PDP Annual Summary were recently published.  Here are the highlights:

1) 9,872 food samples were tested

2) Fresh and processed foods tested were as follows: almonds, apples, avocados, blackberries (fresh and frozen), cherry tomatoes, cucumbers, head lettuce, leaf lettuce, onions, oranges, pineapples (fresh and frozen), potatoes, canned pumpkin, sweet corn (fresh and frozen), tomatillos, and salmon. 

3) Domestic samples accounted for 60.1% of all samples, while 38.9% were imports, 0.9% were of unknown origin, and less than 0.1% were of mixed national origin.

4) Over 99% of the samples tested had residues below the tolerances established by the EPA with 42.3% having NO detectable residue.  

5) As a reminder, the U.S. EPA determines the maximum residue levels (MRL’s) or tolerance of pesticides in food products based upon a standard 100-fold margin of safety to protect all people and the environment.  In addition to this base margin of safety, the FQPA of 1996 imposed an additional 10-fold safety factor (1000X) to protect infants and children, unless sufficient evidence is presented to reduce (Reeves et al., 2019. Adv. Nutr. 10:80-88).

6) A copy of the complete report can be found at the following web-address:

https://www.ams.usda.gov/sites/default/files/media/PDPAnnualSummary.pdf

7) Spread this good news when you have the opportunity to talk to someone about pesticides/agriculture!