"Cracking" Time Again on Peanuts (Prostko)

Many peanut growers are in the field right now making "cracking" applications of paraquat (whether they really need it or not?).  I always get tons of questions about product use rates.  Check out these pictures from earlier today.  These are rates I have been testing for years and they work pretty much all the time (when applied to small weeds 1"-3").  Higher rates and later applications, especially in dryland fields, can push a peanut plant's paraquat tolerance to its limits.   

A few other thoughts:

1) If grower wants to use the 3 lb/gal formulation of paraquat (i.e. Helmquat or Gramoxone 3SL), the normal application rate in these tank-mixtures is 8 oz/A (0.1875 lb ai/A).

2) If a grower wants to use Basagran 4SL (bentazon) instead of Storm 4SL (bentazon + acifluorfen), I would suggest using 8 oz/A of Basagran 4SL.

3) If a grower wants to make his own Storm, I would suggest the combination of Ultra Blazer 2SL @ 16 oz/A + Basagran 4SL @ 8 oz/A.

4) I am not a huge fan of using paraquat + Dual Magnum or any other Group 15 herbicide without some Basagran or Storm to cool it down some on the peanut plant.  

5) No adjuvants are needed when Dual Magnum or Outlook are used (i.e. oil-based formulations) but NIS @ 0.25% v/v (1 qt/100 gallons) is suggested when using Anthem Flex, Warrant, or Zidua.  

6) Do I use i.e. and/or italics too much???? (probably)

Monday Musings (May 16) - Prostko

 A few things from the field earlier today:

1) When you get up early, you get to see some cool stuff!

Irrigating under the "blood" moon from last night (6:31 am)

Rainbows for breakfast!  A great omen for the rest of the week (hopefully).

2) Check out the awesome power of a PRE herbicide (activated with moisture).  These are from my grain sorghum plots.  It's 2 weeks after planting and in plots that are not weedy, there were PRE applications of various residual herbicides including one of the following: Aatrex (atrazine); Moccasin II Plus (S-metolachlor); Parallel (metolachlor); Everprex (S-metolachlor); Parallel Plus (atrazine + S-metolachlor); or Cinch ATZ (atrazine + S-metolachlor).  EPOST treatments were applied today. Not sure why growers, especially those with irrigation, are often reluctant to use a PRE??????????

3) Here's what diuron injury looks like on field corn.  It took 3 days before the symptoms started to show up.  I will let you know what happens to final yield.  

4) I am seeing some good weed control results in my soybean plots with Liberty + Enlist One (applied 19 DAP, V1 soybeans, 3-6" Palmer amaranth).

5)  Peanut growers who use Anthem Flex (carfentrazone + pyroxasulfone) in their paraquat "cracking" applications should expect to see more leaf injury (cosmetic) than when Dual Magnum, Outlook, Warrant, or Zidua are used.  Based upon previous UGA research, this injury should not reduce yields.

  

Monday Musings (May 9) - Prostko

Here are a couple of things to think about based upon recent phone calls/texts and observations from some of my current research projects.

1) If growers observe unexpected/unusual leaf injury/burn after a corn herbicide is applied, it is most likely caused by Valor sprayer contamination.  See below for what this injury looks like and how it could potentially influence corn yields. 

2) When evaluating the potential effects of Liberty on pigweed control, growers should wait at least 7 days before making a final decision on whether or not it worked.  FYI, the colder temperatures this week (< 60 F) will slow down the activity of Liberty for sure.  

3) Peanut growers will be making the decision to spray or not spray an early-postemergence (cracking) herbicide.  If the peanut field was clean at planting and a strong residual herbicide program was used (activated with moisture), it is very likely that a cracking spray will not be needed.  See below (i.e. no weeds in my standard PRE program at 12 DAP):

4) My general recommendations for early-postemergence (cracking) treatments in peanut are as follows:

a) Either paraquat (2 lb/gal) @ 12 oz/A or paraquat (3 lb/gal) @ 8 oz/A + either Storm @ 16 oz/A or Basagran @ 8 oz/A + one Group 15 herbicide [either Anthem Flex @ 3 oz/A or Dual Magnum @ 16 oz/A or Outlook @ 12.8 oz/A or Warrant @ 48 oz/A or Zidua @ 2.5 oz/A (liquid)]. 

Generally, I have no preference between the Group 15's when my suggested PRE/EPOST/POST peanut weed control programs are followed.

b) Add NIS @ 0.25 v/v when using Anthem Flex, Warrant, or Zidua.

c) If need be, growers can make their own Storm (I call it Georgia Storm), by tank-mixing Ultra Blazer (16 oz/A) + Basagran (8 oz/A). This is a slightly different rate than what is applied with current commercial Storm formulation @ 16 oz/A (equivalent to Ultra Blazer @ 11 oz/A + Basagran @ 11 oz/A).

d) Use at least 15 GPA and pressure/nozzle configurations to produce medium to coarse droplets (236-403 microns).  Medium/coarse droplets are yellow and green on this chart.

e) Excessive dust caused by dry weather and tractors driven at Warp Speed 10 will reduce the effectiveness of paraquat.  

NOTE:  Click on pictures for a better view.

Across My Plate Today (Prostko)

A couple of interesting weed science items that came across my plate today that I thought you might find helpful:  

1) A grower sent me the following picture of a Bryozoan spp. jamming up his irrigation system (pond).  I reached out to UGA's former aquatic weed specialist (Dr. Gary Burtle) for some help.  A few fun facts about Bryozoans: 1) Bryozoans are microscopic aquatic invertebrates that live in colonies; 2) their presence in ponds is an indicator of good water quality; and 3) control options include copper complexes and stocking ponds with bream (~500/acre).

*****FYI, I am not interested in becoming the new aquatic weed specialist.  My plate is already very full.  Any future calls to me about pond weeds will result in the following: 1) changing my cell phone number to an unlisted number; 2) early retirement; and/or 3) beginning a new career with normal work hours and no throne calls (i.e. Lowes).

2) At every soybean meeting I attend, you will always hear me talking about the need for Georgia farmers to strongly consider the use of metribuzin (PRE).  Metribuzin is cheap, will provide about 21 days of residual pigweed control, and is not a PPO herbicide.  Check out the following picture from some of my soybean plots earlier today.  More than 40+ Palmer amaranth plants/ft2 in the non-treated control (NTC) and ZERO plants where metribuzin was used.

  3)  Metribuzin is available as a solo product and/or as a component of numerous pre-mixes.

4) Growers who want to use metribuzin in soybean must plant a tolerant variety (page 279 of 2022 UGA Pest Control Handbook-Volume 1) and pay very close attention to planting depth (at least 1.5"), rate of application (0.25 lb ai/A), and soil organic matter/texture. 

https://extension.uga.edu/content/dam/extension/programs-and-services/integrated-pest-management/documents/handbooks/2022-comm-chapters/Soybean.pdf

Empyros™ Herbicides for Field Corn? (Prostko)

I received a few questions about "new" corn herbicides being sold by Helena® under the trade name of Empyros™.  Here is some information for you in case you get asked questions:

1) There are three different products being sold under that brand name.  I was under the impression that only the Empyros™ formulation would be sold in the south but I could be wrong on that one.

2) Last year was the first time that I had the opportunity to evaluate these specific pre-mixes.  Generally, they performed very well but I only have 1 year of data.  I just planted another test on Monday (03/28/22) to get another look. Check out these field pictures from 2021:

3) For more information, check out the product labels:

https://s3-us-west-1.amazonaws.com/agrian-cg-fs1-production/pdfs/Empyros_HAE_Label.pdf

https://s3-us-west-1.amazonaws.com/agrian-cg-fs1-production/pdfs/Empyros_Triad_HAE_Label.pdf

https://s3-us-west-1.amazonaws.com/agrian-cg-fs1-production/pdfs/Empyros_Triad_Flex_HAE_Label.pdf

4) The active ingredient, tolpyralate, is also sold under the trade name of Shieldex® 400SC from SummitAgro™USA.  After collecting multiple years of data, Shieldex® was added to the "official" field corn weed control recommendations in the 2022 UGA Pest Control Handbook Vol. 1 (page 69).  Check out this field picture from 2021:

5) A copy of the Shieldex® label:

https://s3-us-west-1.amazonaws.com/agrian-cg-fs1-production/pdfs/SHIELDEX_400SC2k_Label.pdf

6) Tolpyralate is a WSSA Group 27 herbicide (HPPD inhibitor) thus is very similar to other actives in this group such as tembotrione (Laudis®), mesotrione (Callisto®), and topramezone (Impact®).

Pigweed At Burndown? (Prostko)

I received this picture from a grower yesterday who was about to burndown with some Roundup (before looking in the field).  This field was treated with a Roundup + 2,4-D combo several weeks ago (but no residual).  Two main takeaways here:  1) always a great idea to include a residual herbicide in a preplant burndown weed control program especially when applied many weeks before planting; and 2) the very best thing a grower can put in a field is a foot.  In this scenario, Roundup would not have been a great option because of resistance.  The grower wisely switched to Gramoxone (and was also including Dual Magnum) since he will be planting field corn and soybean. 

 

Preplant Burndown Update (Prostko)

Some responses to a few common questions this week about preplant burndowns:

1)  What is the plant-back restriction for field corn following an application of 2,4-D?

Plant-back restrictions for field corn after a burndown application of 2,4-D are 7 days (16 oz/A) or 10-14 days (>16 oz/A)

2) If a grower cannot wait to plant field corn in 7-14 days after an application of 2,4-D, what other burndown options are available? 

Roundup (glyphosate) or Gramoxone** (paraquat) + Atrazine 4L (32 oz/A) is my first choice.  There are no field corn plant-back restriction for these treatments.  Check out the following picture from my burndown plots yesterday in a Tift Co. growers' field (many thanks to Justin H. and Regan V.).

3) What's the best option for controlling a failed stand of field corn?

It has been my experience that the best option for controlling a failed stand of field corn is to use Select Max 0.97EC (or other equivalent formulations) @ 6 oz/A + NIS. But, there is a for real 6 day plant-back restriction (field corn) for this treatment.  Since many of our current field corn hybrids have tolerance to both Roundup and Liberty, neither of these are great options.  Gramoxone has been too inconsistent for me to have much confidence.  FYI, it takes about 10-14 days before you really start to observe the full effects of Select Max.  

4) What is our current recommended preplant burndown program for peanut?

Roundup or Gramoxone** + Valor @ 2 oz/A + 2,4-D (1 pt/A).  An additional 2 oz/A of Valor can be applied at planting.  Peanuts can be planted anytime.

**When using Gramoxone on small grain cover crops, applications need to be made when seedheads are present.