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.