Some Answers to Common Questions (Prostko)

I can tell things are busy right now because my phone has been ringing off the hook.  Here are some quick answers to some common questions that I have gotten recently:

1) Can I spray paraquat + Storm + Dual cracking treatments on peanut at night?

For now, I would say that this might be a bad idea since there is little or no peanut data to support this type of application.  For the past 17 years, all of my cracking treatments have been applied between the hours of 6 am to 9 am.  Perhaps, night applications might be something I should look into for 2015.  Research conducted in Arkansas suggested that volunteer corn control with paraquat would be greater at sunset than at sunrise.  In Texas, cotton dessication/defoliation with paraquat was better when applied at 6:00-6:30 pm compared to earlier in the day.  However, remember that many plants experience diurnal (night) leaf movements which could impact spray coverage which is extremely important for the success of any paraquat treatment.

2) Can I tank-mix Dual Magnum with peanut fungicides to get longer residual control of Palmer amaranth?

Yes.  In 2013, I tank-mixed Dual Magnum with the following fungicides at 52 DAP (R2 stage of growth, 8" tall): Tilt/Bravo; Headline; Abound; Provost; and Fontelis.  These tank-mixtures resulted in approximately 10% peanut leaf burn.  This injury had no effect on final yield.  A similar test is being conducted in 2014.

3) Why do I not want Georgia soybean growers to use Valor, Prefix, or Reflex PRE?

A) Georgia growers are already over-using the PPO herbicides in cotton and peanut.
B) Almost every acre of soybean in Georgia will need a POST treatment for Palmer amaranth control.  The only soybean herbicide that will provide both PRE (residual) and POST control of Palmer amaranth is Reflex.  Thus, Valor, Prefix, or Reflex PRE followed by Reflex POST is a very bad idea!!!!!!!!!
C) Georgia soybean growers should seriously consider using alternative PRE herbicides such as Dual Magnum, Warrant, or Boundary.

Replanting Cotton after Using Warrant (Culpepper)

1. Label: There are no preplant restrictions on the label for cotton which means you could apply Warrant anytime prior to planting……or replanting.

2.  Culpepper thoughts:

A. I strongly discourage you from following Monsanto’s preplant label recommendation for Warrant; our data suggests injury from Warrant can be significant if planting to quickly behind a Warrant application.

B. Our data and experiences suggest the following:

No-till into 3 pt Warrant	Strip-till in to 3 pt of Warrant
7 days = 30 to 50% stunting	7 days = 0 to 20% stunting
14 days = 0 to 30% stunting	14 days = no stunting
21 days = no stunting	21 days = no stunting

C.  Things to Consider:

1.  I have no clue how much Warrant is in the planting zone after 4 inches of rain.  If the Warrant is gone then these suggestions are conservative but these results have been consistent over the past 3 years. 

2.  We are developing an irrigation system to help us use research to better understand where herbicides are located in the soil profile and how active they are after varying amounts of rainfall/irrigation have occurred.  This system should be operational for next season’s crop.

3.  I have gotten so many calls about Warrant, I will have several different demos available for viewing on our June 26 tour.

**For Agents Eyes Only!

Counter in Cotton (Culpepper)

1. Label: The Counter label prohibits the use of Diuron, Cotoran, Caparol, Cotton Pro, Staple, Pyrimax, and Envoke from use when using Counter.

2.  DuPont:  Does not support or recommend the use of Staple following Counter use in cotton.

3.  Culpepper:

A.  I am clueless why this label was brought forward without any real understanding for potential interactions with Counter and several of the most commonly used herbicides in cotton.

B.  I have one study in progress including all of these herbicides; no injury issues so far.

 

C.  Follow the label.

D.  If you have questions call Bob Kemerait (229-392-0498) or Gerald Harrison (229-392-2590) or better yet, give them both a call.

E.  Do not call me about this issue because I really cannot add anything.  Anytime we talk I share data results; however in this case, I have no data so I don’t have anything to say. 

F.  If you are obtaining experiences this season please share those with me so we can begin generating the data that should have been developed before the label was released. 

** For Agents Eyes Only!

Peanut Injury Update (Prostko)

In the past 2 days, I have received numerous phone calls, texts, smoke signals, homing pigeons, and e-mails about peanut injury caused by Valor.  Peanut fields planted the week of May 5 that were hit by the heavy rains on May 14-15 are likely to have some level of injury (Figure 1).  Here are a few thoughts to consider:

1) Valor injury should not be a surprise to anybody since this phenomenon has been observed for 13 years.  Cracking peanuts (+1-2 weeks) treated with Valor that receive heavy rainfall will be injured almost all the time!!!

2) There is a good amount of UGA data to suggest that, in most cases, the peanuts will recover from this injury without yield loss even at a 2X rate (i. e. 6 oz/A) (Figure 2 + 3).

3) Recent UGA research conducted by Drs. Jason Sarver and Scott Tubbs would suggest that there is no yield or economic benefit to replanting a peanut field if populations are at least 2.5 plants/ft (single row) or 3.0 plants/ft (twin row).  Thus, I would not worry too much about Valor injury unless plant populations fall below these levels (assuming the stand is uniform and not skippy).  

4) Contrary to older dogma, peanut j-rooting is not always caused by herbicides such as Dual or Warrant.  Today, I found numerous peanut plants in my untreated plots (i.e. no herbicides) that are exhibiting this symptom (Figure 4).  Many other factors can cause j-rooting including individual seedling vigor, environmental conditions (cold/wet), and soil compaction. 

Figure 1.  Valor Injury in Peanut

Figure 2. Peanut Yield Response to Valor - 2009

Figure 3.  Peanut Yield Response to Valor - 2013

Figure 4.  J-rooted peanuts not treated with any herbicide.

Excessive Injury with Liberty in WideStrike Cotton Currently Being Noted (Culpepper) - For Your Eyes Only

Early last week, I applied Liberty to WideStrike cotton throughout the state and I am now observing the highest level of injury that I have ever observed with Liberty in WideStrike cotton.  The increased level of injury is likely a response to our excessively moist environment.

Things to consider:

1. Try to avoid spraying Liberty on Widestrike cotton during our current extremely moist environment.  The best way to avoid the need for Liberty is overlapping residual herbicides as defined on the laminated handout you were given.  There are NO preemergence herbicide mixtures lasting longer than about 18 days and don’t forget you have to get the POST residual herbicide out and activated prior to the prememergence herbicide breaking.

2.  If spraying Liberty on WideStrike cotton, don’t overdo the rate.

3.  If spraying Liberty on WideStrike cotton, do not add any adjuvant.

4.  If spraying Liberty on WideStrike cotton avoid mixtures with Dual, Warrant or Staple at this current time.

5.  Remember neither Dow nor Bayer support the use of Liberty in WideStrike cotton.

6.  I would expect to return to normal injury levels once we are not swimming.

7.  No concerns spraying Liberty on GlyTol/LL cotton.

Reflex Issues in Vegetables (Culpepper) (For Your Eyes Only)

Agents, over the last couple of days we have had several serious mistakes made with Reflex in vegetables.  These mistakes are not related to UGA Extension and are not in accordance with the label. We must help our growers avoid these issues if possible. The objective of these labels is to provide new helpful weed management tools; however, these incidences could challenge our ability to continue using/developing third party labels (we have 28 now) such as Reflex in watermelon, squash, and/or pumpkin.

A few thoughts regarding current injury mistakes:

1.  Below is the newsletter I sent out a month or so ago; please review it once again.

2. Reflex will destroy most vegetables with ANY foliar contact; SO DON’T SPRAY IT OVERTOP (exception is snap bean, see 2014 UGA Pest Control Handbook).

3. Reflex can kill cucumber twice and can kill cantaloupe at least once regardless of application method; thus, there is no Reflex label for cucumber or cantaloupe and there will not be a label.  Therefore, make sure your growers understand that herbicides are not like many fungicides or insecticides that can be applied across crop groupings. 

4.  Please remind your growers about these labels and how these labels will help avoid serious issues.  Agents MUST NOT give growers any indemnified label.  Additionally, I would suggest agents not make any recommendation to a grower until that grower has printed and reviewed the label. 

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Reflex Labeled for Georgia Watermelon, Squash, and Pumpkin.  (Culpepper)  These new herbicidal tools are a result of cooperative efforts involving The University of Georgia, Syngenta, IR-4, The Georgia Department of Agriculture, The Georgia Agricultural Commission for Vegetables, and Industry. It is critical that agent’s help growers understand that their specific production practices may alter weed and crop responses to recommended herbicides. 

Important Points:

1.  Growers must have a label in hand when using Reflex in these crops.  These labels are written by myself and Syngenta so if there is any confusion let me know.

2.  Agents MUST NOT give growers any indemnified label.  Growers must follow the steps below to obtain their own label.  The process of Growers obtaining labels is actually the method being used to indemnify the use of Reflex in these crops.  If an agent was to provide a grower the label, it may make the agent or even UGA liable if issues were to occur. 

3.  Growers must evaluate these programs on limited acres until gaining experience.  Keep in mind these labels are developed from 10 to 15 studies conducted primarily by my research here in Georgia; most other pesticide labels are developed from over 200 replicated trials conducted by dozens of scientist across the country.  

4.  I have created a watermelon circular, similar in format to the cotton circular.  The circular should be up on our website at gaweed.com by March 12, 2014 or if you would like laminated copies for your growers, email me the number you would like and a shipping address.

5.  Support Syngenta and use Reflex; no generic company has shown any desire to support such challenging label development!!!!!!!!!!!!

Obtaining the label:

1.  Go to www.farmassist.com

2.  Select products along top bar.

3.  Select indemnified labels (4^th one down).

4.  Login (first time users create login and password).

5.  For state, select Georgia and for product, select Reflex in this scenario (play around and see

our other labels) and then submit.

7.  Select the Reflex label and crop of interest and submit.

8.  Accept waiver; this is the process making the label an indemnified label.

8.  Print label and have present during application.

Warrant + Valor for Weed Control in Peanut (Prostko)

As I sit in my office watching yet another rain event (April 29), I am wondering why most GA growers seem to have a passion/obsession for using Warrant in every row crop possible.   It must have something to do with the Monsanto Rewards Program.  Anyway, I have been getting a lot of questions about mixing Warrant + Valor for PRE weed control in peanut.  Here are a few random thoughts:

1) The combination of Valor + Warrant is a perfectly legal/labeled option for GA peanut growers.

2)  Using Warrant PRE (except when planting later in May in fields with a history of tropical spiderwort/Benghal dayflower) in my opinion is a waste of its residual power.  There is not a lot of evidence in peanut to suggest that Warrant + Valor is significantly better on Palmer amaranth than Valor alone (i.e. assuming starting clean and rainfall/irrigation activation).

3) Warrant is not very effective on Texas panicum. That is why I always recommend either Prowl or Sonalan in combination with Valor.   You can probably count on 1 hand the number of fields in GA that do not have Texas panicum????? OK, there might actually be more than 5 fields???

4) I believe a better fit for Warrant in early planted peanut fields is to use it in combination with POST herbicides such as Gramoxone or Cadre.  However, the current Warrant label prohibits the use of Warrant on peanuts that are flowering.  A big mistake on Monsanto’s part which I hope will be corrected in the future.

5)  Early planted peanut fields are usually subject to cooler and wetter conditions which can lead to greater injury from PRE applied residual herbicides.   Although I have not yet observed this phenomenon in the field, Valor + Warrant or Dual could be more injurious to peanut than either applied alone in the wrong situation (low vigor/germ seed, improper planting depth, heavy rainfall, high rates, etc.).

6) As indicated in a previous blog, I have not observed any real differences between Warrant and Dual Magnum when used in a peanut weed management program.  As far as I am concerned at this point, flip a coin on these two!!!  FYI, Dual is more effective on yellow nutsedge than Warrant.