Weed Science Update - November 2017 (Prostko)

Just a few weed science items that I thought you might find of interest.  Some may be new or old news?

1) Enlist One, from Dow Agrosciences, is a new 2,4-D choline formulation registered for use on Enlist crops (2,4-D tolerant).  As you may recall, Enlist Duo is a pre-mixture of glyphosate + 2,4-D choline.  According to my secret sources, Enlist cotton varieties were planted on ~2% of the acreage in Georgia.  A copy of the Enlist One label can be viewed or downloaded from the following location:  http://www.cdms.net/ldat/ldE27000.pdf.  I am not  sure yet what the final shakeout is with the Dow/Dupont merger.

2) FMC has acquired the following herbicides from DuPont: Affinity, Agility, Ally, Express, Finesse, FirstShot, Glean, Harmony, Harmony Extra, Panoflex, Sentrallas, Upbeet.

3) Agrium/Crop Production Services (CPS) has acquired 20 Southern States locations in Georgia and Florida.

4) BASF is buying Bayer's seed business (canola, cotton, soybean) and Liberty-Link business.

5) If interested, final results from my 2017 weed control field trials can be found at the following location:  http://gaweed.com/reports.html

6) Annual UGA Weed Science Update for county extension agents is on December 6 in Tifton.  Tentative agenda is as follows:

2017 UGA Weed Science Update Agenda

Date: December 6, 2017

Location:  Tifton Campus Conference Center (RDC)

Times: 9:15 am - 3:30 pm

Agenda

9:15-9:30 am                             Light refreshments

9:30-10:00 am                           Peanut (Prostko)

10:00-11:00 am                         Using Pesticides Wisely – Agent Responsibilities and Update (Culpepper)

11:00-11:30 am                          Field Corn (Prostko)

11:30-12:00 pm                         Cotton (Culpepper)

12:00-12:30 pm                         Lunch on site

12:30-1:00 pm                           Nozzle Demonstrations (Carter)

1:00 -1:30 pm                            Soybeans (Prostko)

1:30- 2:00 pm                            Small Grains (Culpepper)

2:00-2:15 pm                             Break

2:15-2:45 pm                             Miscellaneous Crops (grain sorghum, sunflower) (Prostko)

2:45 pm – 3:30 pm                    Vegetables (Culpepper)

3:30 pm                                     Program Evaluation/Adjourn

2018 Dicamba Label Changes (Prostko and Culpepper)

Due to the recent concerns about off-target movement of dicamba, the EPA has mandated significant label changes for Engenia®, Fexapan™, and Xtendimax® for 2018.  Some of these important label changes are as follows:

1) Engenia®, Fexapan™, and Xtendimax® will now be considered Restricted Use Pesticides.

2) Growers who use Engenia®, Fexapan™, and Xtendimax® will be required to keep the following records for a period of 2 years, records must be generated within 14 days of application, and a record must be kept for every application:

a.     Certified Applicator Name

b.     Applicator Certification Number

c.     Product Name

d.     EPA registration Number

e.     Total Amount Applied

f.      Application Date

g.     Crop or site of application
h.   Location of application

i.       Size of area treated

j.       Training Requirement: Proof of auxin training

k.       Application timing: PRE or number of days after planting

l.       Receipts of Product Purchase

m.    Products Labels
n.   Buffer Requirement: record buffer distance calculation

o.    Sensitive Crop Awareness: Applicator must survey and document neighboring fields for sensitive areas or crops

p.     Spray Systems Cleanout:  Must be documented that applicator complied with label.

q.     Tank-Mix-Products: complete list of all approved products that were tank-mixed

r.     Application Start and Finish Times

s.      Nozzle Selection

t.      Air Temperature:  At boom height for start and finish

u.     Wind Speed/Direction: At boom height for start and finish

     

3) Fexapan™ and Xtendimax® minimum GPA changed to 15 gallons.
4) Can only be applied when wind is between 3 MPH and 10 MPH.
5) Can only be applied from sunrise until sunset.

Most growers will not be happy with these label changes.  However, failure to comply and/or increases in off-target movement of dicamba will likely result in the EPA’s cancellation of these products.  We will do our very best to keep you informed of any other significant changes. 

Weed Science Update - August 10 (Prostko)

A couple of reminders based upon my phone calls and e-mails over the last few days (click on Figures to view in larger format).

1) Revenge spraying large pigweed plants is not a viable option for growers who have been untimely due to rainfall or other circumstances (Figure 1).  Options for escaped weeds include hand-weeding or using a 50% solution of paraquat in a non-selective applicator (NSA) (Figure 2).  A NSA is more effective in peanut than soybean due to the height differential between the crop and weed (i.e. more of the weed gets treated in peanut).  Check out page 215 of 2017 UGA Pest Control Handbook for more information about the use of NSA in peanut.

2) Options for controlling Florida beggarweed in peanut at this time of year include a postemergence application of Classic, paraquat in a NSA, hand-weeding, or mowing.   Our data has shown that when grown under weed-free conditions, Classic can cause 7% to 11% yield reductions when applied to GA-06G.  Thus, growers who want to use Classic must weigh this potential yield loss against the negative effects that large beggarweed plants can have on fungicide deposition and harvest efficiency as the season progresses.  If beggarweed populations are dense enough to impede fungicide deposition and/or cause a digging nightmare, the use of Classic is justifiable.  Check out page 214 of 2017 UGA Pest Control Handbook for more information about the use of Classic in peanut.

3) Field corn producers with pigweed and tropical spiderwort/Benghal dayflower (TSW/BDF) problems need to seriously consider a post-harvest control strategy (Figure 3 and 4).  Post-harvest control programs for field corn are presented on page 86 of 2017 UGA Pest Control Handbook.  Post-harvest control programs for TSW/BDF are discussed on page 73 of 2017 UGA Pest Control Handbook.

What's Up This Week (Prostko)

A couple of interesting things to share with you this week:

1) Check out the following picture sent to me by Dr. Alan York (NCSU).  On day 1, Mr. Peanut Grower mixed 2,4-DB and dry manganese sulfate in 700-800 gallons of water with no problems.  On day 2, Mr. Peanut Grower mixed the same combo with only 100 gals of water and OH NO!!!!.  A great advertisement for pre-slurrying dry formulations prior to mixing in a big tank.

2)  Much ado in the the Mid-South about off-target movement of dicamba.  We have experienced a few problems in GA but nothing compared to what's going on there.  Just recently, I was asked how non-dicamba soybean yields could be affected by off-target movement of dicamba.  Although soybeans are very sensitive to dicamba and low rates will cause leaf cupping and epinasty, vapor drift rates (1/1000th X) and particle drift rates (1/100th X) will likely cause yield losses of < 9% depending upon the soybean stage of growth.

3) Current list of dicamba tolerances (i.e. how much residue in a crop is legal) can be obtained at the following web-site:

https://www.law.cornell.edu/cfr/text/40/180.227

Recent Tank-Mix Issues (Prostko)

Last week, I received a few calls and pictures from some folks about tank-mixes and peanut injury (Figures 1 and 2).  I will remind you that there is nobody on the planet that can assure any peanut grower that a tank-mix will be 100% safe and 100% effective all the time. There are too many variables to consider including the number of products in the spray tank, GPA, air temperature, humidity, leaf wetness, overall peanut plant health, and time of day.   I think part of the problem last week was our higher than normal temperatures (Figure 3).  A few tips for growers considering spraying untested tank-mixes:

a) Limit the number of products that are put in a spray tank.  Bite the bullet and make separate applications when practical.
b) Spray early in the morning when air temperatures are lower and the peanut plants have not been baking in the sun all day.
c) Increase water volumes from 10 GPA  to 15 GPA (less concentrated spray droplets).

Figure 1.  Peanut response to Convoy + Alto + Bifenthrin fb Select + COC
 1 hour later (i.e. really a 5 way tank-mix)

Figure 2.  Peanut response to Propulse + 2,4-DB (i.e. really a 3 way tank-mix)

Figure 3.  Maximum air temperatures, Attapulgus (GA), June 30 to July 7, 2015, 2016, 2017
(Source:  UGA Automated Weather Network)

Weed Science Update - June 16 (Prostko)

Just got done rating some of my soybean weed control plots.  Thought I would pass along these few thoughts.

1) Not sure what to say when someone asks me "When are you guys going to figure out how to control pigweed?"  I am pretty confident that we have but not everyone listens or can get it done! (Figure 1).

  

Figure 1.  General overview of 2017 soybean weed control plots in Ty Ty, GA.   Notice weedy-checks in comparison to other plots (started clean + activated residual + timely POST).

2) I fear that some are thinking that the new auxin technologies are the greatest thing since sliced bread.  That would be very stale sliced bread since 2,4-D has been around since the 1940's and dicamba since the 1960's.  I am still getting great results with other chemistries (Figure 2).

Figure 2.  Soybean weed control in 2017 with Tricor (metribuzin) followed by Roundup PowerMax (glyphosate)+ Reflex (fomesafen).

3) If growers decide that they must use the auxin weed control systems, I cannot over emphasize the need for residual herbicides in these programs (Figure 3).

Figure 3.  Weed regrowth/emergence (1 sq. ft.) 25 days after a single application of Roundup PowerMax (28 oz/A) + Xtendimax with VaporGrip (22 oz/A).

  

Valor Injury or The Sky Is Falling (Prostko)

My right ear is currently bleeding due to the numerous telephone calls that I have received over the last few days about Valor injury in peanuts.  Peanuts that were planted approximately 10 days ago or so were in a great place to get hammered from Valor because of the recent rainfall events (Figure 1).   Everyone seems to be panicking as though this was a surprise??????  If it rains on Valor treated peanuts when they are cracking and small (~2 weeks after cracking), injury will occur.  Peanuts typically recover from this injury without a yield penalty.  Check out Figures 2 and 3 from some of my research back in 2009.  In this trial, more than 5" of rainfall occurred in the 30 day period after peanut planting.  Peanut injury was significant but yields were not reduced even at a 2X rate.  Not sure what else I can say or do at this point???

Zidua Peanut Label (Prostko)

On Friday afternoon, May 19, I received word from BASF that Zidua (pyroxasulfone) was labeled for use in peanut.  I have been conducting peanut research with pyroxasulfone for more than 10 years (over 47 field trials).  In a nutshell (no pun intended), Zidua will compete with Dual Magnum or Warrant in our POST peanut herbicide programs for the residual control of Palmer amaranth and a few other weeds (Figure 1). Some advantages for Zidua include its lower use rate (1.5 oz/A-2.1 oz/A) and improved control of other broadleaf weeds such as Florida beggarweed.  Generally, I have observed no real differences in performance/yield between Zidua, Dual Magnum, and Warrant when used in a complete peanut weed control program (Table 1). A copy of the supplmental peanut label can be obtained at the following web-address: http://www.cdms.net/ldat/ldAMK017.pdf

Figure 1.  Zidua vs. Dual Magnum Programs in Peanut - 2016.

Table 1.  Dual Magnum/Warrant/Zidua Peanut Weed Control Programs - 2014.

Common Cocklebur in Peanut (Prostko)

Chris Tyson (Tattnall County) recently sent me a picture of a common cocklebur seedling (Figure 1).  In 2016, Brian Hayes (Grady County) had a peanut grower with a very serious cocklebur problem (Figure 2).  In fact, that peanut field in Grady County was probably the first time that I ever made a recommendation just for that specific weed.  At one time though, cocklebur used to be a more widespread weed problem but sorta disappeared during the "glyphosate era".   Peanut herbicides with good to excellent activity on cocklebur include the following: 2,4-DB, Basagran, Cadre, Cobra, Gramoxone (paraquat), Pursuit, Storm, Strongarm, and Ultra Blazer.  On the downside, Valor is not very effective on this weed so don't be surprised if you see cocklebur in a Valor treated field. The fruiting structure of cocklebur (i.e. the big bur that sticks to your favorite shirt or hunting dog) contains 2 seeds, one for now and one for later.   

Figure 1.  Common cocklebur seedling (Source: Chris Tyson)

Figure 2.  Common cocklebur infestation in a Grady County peanut field, 2016.

Peanut Injury Likely (Prostko)

Rainfall events today will likely result in the development of Valor injury on peanut, especially in fields where the peanut plants are just beginning to emerge/crack.  In preparation for any upcoming questions, please refer to my Weed Science Blog on May 20, 2014.  This should help refresh your memory.  No need to re-invent the wheel.

http://ugaweedscience.blogspot.com/2014/05/peanut-injury-update-prostko.html

Field Corn Weed Control Update (Prostko)

Field corn weed control does not have to be difficult.  Just about any of the herbicide programs that growers are using in Georgia do a good job of controlling most weeds, especially Palmer amaranth, when applied to small plants (<3" tall). Want some proof? Check out the following pictures from my field corn plots that I rated earlier today (click on pictures to make them larger).  Just so you know, these herbicide treatments were applied 17 days after planting with a CO2-powered backpack sprayer calibrated to deliver 15 GPA at 3.5 MPH using AIXR 11002 nozzles.

The most troublesome weed in Georgia field corn, in my opinion, is annual morningglory.  Field corn growers who struggle with morningglory should seriously consider a post-directed/lay-by application of Evik (ametryn) sometime after their initial POST treatment was applied.  Check out page 70 of the 2017 UGA Pest Control Handbook for more information about Evik.  The minimum corn height for post-directed applications of Evik is 12".  If Evik is tank-mixed with glyphosate, post-directed applications can be applied up until 48" tall corn (RR2 hybrids).

Glyphosate/Atrazine/Adjuvants in Field Corn (Prostko)

A common question this week from field corn growers is "Do I need to add a crop oil concentrate (COC) when applying glyphosate + atrazine?"  For you Roundup babies out there, Atrazine + Prowl + COC was one of the most common and effective field corn herbicide treatments in Georgia before the introduction of RR-crops.  Thus, it is tough for seasoned field corn growers to consider not using a COC.  With that said, there is no need to use a COC when a fully "loaded" formulation of glyphosate is used.  Fully "loaded" glyphosate formulations already contain enough adjuvants.  In fact, COC's have been known to cause antagonism when mixed with glyphosate.  

Fully "loaded" glyphosate formulations include the following:  Abundit, Barbarian Max, Buccaneer Plus, Cornerstone 5 Plus, Credit/41Extra, Credit Xtreme, Duramax, Durango DMA, Gly-Fos Xtra, Glysort Plus, Gly Gold Extra, Gly Star Plus, Helosate Plus, Helosate 70, Mad Dog Plus, Makaze, Roundup PowerMax, Roundup WeatherMax, Showdown, Touchdown CT, Touchdown IQ, Touchdown Total.

In my own research program, I have not been using additional adjuvants with Roundup + Atrazine for a very long time (Figure 1).

If a grower uses a glyphosate formulation that is not loaded at all or is partially loaded, then he/she should consider adding a non-ionic surfactant (NIS) @ 0.25% v/v or 1 qt/100 gal.

Figure 1. A common field corn weed control program.  No adjuvants were used with the POST treatment of Roundup PowerMax + Atrazine.  FYI, this entire herbicide program costs approximately $16.50/A (excluding application costs).

Replanting Field Corn and Weed Control (Prostko)

The recent frosty weather has resulted in the need for some corn fields to be replanted. Some of those fields may have already been treated with a PRE application of atrazine. Since it is likely that these fields will have to be re-tilled, there have been some questions on what to do next.  Here are a few comments to consider:

1) Field corn is extremely tolerant of atrazine so crop injury should not be a concern. 

2) The maximum amount of atrazine that can be legally be applied in a field when both PRE and POST applications are used is 2.5 lbs ai/A (i.e. 2.5 qts of 4L).

3) Atrazine could be used again PRE on the replant but that would limit the amount that could be applied POST.

4) In those fields that have already been treated with atrazine and are tilled/replanted, I would suggest that growers switch to another PRE herbicide such as Dual II Magnum 7.64EC (16-21 oz/A) or Warrant 3ME (48 oz/A).  This way, growers can use an additional 1.5 qts/A of atrazine in their POST application of glyphosate or other favorite and remain within the label restrictions. 

4) When using these chloracetamide herbicides in field corn, it is also a good idea to make sure that there are no potential hybrid sensitivity issues (really not that common).  Generally, this information can be obtained from the seed companies.  

Pioneer: https://www.pioneer.com/CMRoot/Pioneer/US/products/stewardship/2016-corn-herbicide-ProdList.pdf

Dekalb: No specific ratings for amide tolerance?

Mycogen:  Field corn hybrids rated for careful management (i.e. limit overlap and high rates) include the following: MY90R27RA, MY13K77RA, CNX157144S3, F2F499, and TMF86H77RA. 

Sprayer Clean-Out and Tank-Cleaners (Prostko)

With all the ado about 2,4-D and dicamba-tolerant crops theses days, there is some concern about sprayer cleanout after application of Enlist Duo, Engenia, Fexapan, and Xtendimax.  I would encourage all applicators to read and follow the specific sprayer clean-out instructions listed on the herbicide labels. Here are some useful links: 

2017 Enlist Duo Product Use Guide (automatic download of document - sprayer clean-out procedures listed on pages 20-21)
http://www.enlist.com/~/media/enlist/enlist-ahead/resource-pdfs/2017_enlistallcrops_pug_final.ashx

Engenia Clean-Out Recomendations:
http://agproducts.basf.us/campaigns/engenia/assets/pdf/Engenia-Spray-System-Cleanout-TIB.pdf

Fexapan Sprayer Cleanout
http://www.dupont.com/products-and-services/crop-protection/soybean-protection/articles/sprayer-cleanout.html

Xtendimax Cleanout (video presentation)
https://youtu.be/LzywJ-YSta4?list=PLWKeHPsbiIP7URV05Y03YTMfYxGLmQ3sF

I called a few local chemical dealers and the following are some commercial tank-cleaners that are currently being sold in Georgia (listed in no particular order):

1) WipeOut XS
https://s3-us-west-1.amazonaws.com/www.agrian.com/pdfs/WipeOut_XS_Label.pdf

2) Valent Tank Cleaner
https://www.valent.com/Data/Labels/1714-B-ValentTankCleaner.pdf

3) Nutra-Sol Tank-Cleaner
http://www.cdms.net/ldat/ldDC2000.pdf

4) All Clear
https://s3-us-west-1.amazonaws.com/www.agrian.com/pdfs/All_Clear_Label4.pdf

5) ProTank Cleaner
http://www.winfield.com/cs/groups/lolweb/@winfield/documents/web_content/ndjf/mzax/~edisp/36142_301402.pdf

6) Neutralize
http://www.cdms.net/ldat/ldDC1000.pdf

One-on-One Trainings, Using Pesticides Wisely, Buying Seeds or Herbicides, Cotton and Vegetable Circulars – Addressing Agent Questions (Culpepper)

One-on-One Trainings: 

Question: Can the one-on-one training replace the Using Pesticide Wisely Training? Answer: no, no and NO. One-on-one trainings are to compliment the Using Pesticides Wisely Training but cannot but used to replace it. If you do not attend the Using Pesticide Wisely training then you cannot legally be the person responsible for an application of 2,4-D or dicamba in tolerant crops (soybean or cotton).

For those of you that did not join in the mock one-on-one trainings, it was recorded. Scott Utley and Wade Parker have both sent the link out numerous times. Your efforts with the one-on-one trainings have the potential to be monumental and keep in mind you will collectively accomplish something that has never been done………….ever !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Using Pesticides Wisely: 

Question: What happens if I miss all of the Using Pesticides Wisely Trainings? 
Answer: You implement a sound alternative program without 2,4-D or dicamba in-season. By March of 2017, there will have been 36 meetings over 3 years, pretty sure several meetings have been close to each applicator or person responsible for the application. Additionally, well over 2000 people have now attended the training. Not sure what else needs to be said???

HELP!! In 2015 some growers registered under farm names. This is not a big deal at all but I need your help getting actual grower names for those farms. So if someone from your county registered as a farm name, please e-mail me the grower or growers names, pesticide license number, address, and their e-mail (if they have one). Again, this would have only happened for the 2015 list. We cannot give a Using Pesticide Wisely card to the farm, so please help us address this issue.

Buying Seeds or Herbicides: 

Question: If I don’t take the Using Pesticide Wisely training does that prevent me from buying any seed or herbicides? 
Answer: No, absolutely not. Restricting the purchase of any seed or herbicide may promote the use of older formulations of 2,4-D or dicamba which we do not want any part of. It really is simple, the training allows one to LEGALLY make an application of 2,4-D or dicamba in-season for tolerant crops. Labels making this clear can be found at the Department of Agriculture’s Using Pesticides Wisely Website: www.agr.georgia.gov/24c.aspx

2017 Cotton and Vegetable Circulars are uploaded to the UGA Weed Science Web-Page @ www.gaweed.com. All three cotton circulars as numerous vegetable circulars should be able to be printed as needed. Of course, as I travel the state, you are welcome to the ones I have already laminated.  FYI, Prostko also has his weed control recommendations listed for all of his crops on our web-site.

Dicamba-Tolerant Crop Updates (Prostko)

Lots of action this week for the new dicamba formulations that can be used on dicamba-tolerant cotton and soybean.  Here is some news:

Fexapan with Vapor Grip:  Dupont's dicamba-DGA formulation for use on tolerant crops received its federal approval.  State labels are soon to follow?

A copy of the EPA approval letter can be obtained here:
https://www3.epa.gov/pesticides/chem_search/ppls/000352-00913-20170207.pdf
  
For additional technical information about Fexapan:
http://www.dupont.com/products-and-services/crop-protection/soybean-protection/products/fexapan.html

Engenia (BASF):  Additional tank-mixtures (9 adjuvants) have been approved for use including the following: Induce, Astonish, Class Act Ridion, Contrast, Fastrate, Impetro, Intact Xtra, Jackhammer Elite, Kabak Plus.

Xtendimax with Vapor Grip (Monsanto): Additional nozzles (20 total) are now approved for use.  See below:

                                                                 Operating Pressure (PSI)

Manufacturer	Nozzle Type	10	20	30	40	50	60	70	80	90	100
Greenleaf Technologies	TADF-D11003		Min 20		Max 40
	TADF-D11006		Min 20			Max 50
	TDXL-D11003		Min 20		Max 40
	TDXL-D11004		Min 20			Max 50
	TDXL-D11005		Min 20				Max 60
	TDXL-D11006		Min 20				Max 60
Hypro	ULD12004		Min 20		Max 40
	ULD12005		Min 20		Max 40
Lechler	ID11003			Min 30	Max 40
	ID11004			Min 30	Max 40
	ID11005			Min 30	Max 40
	ID8004			Min 30	Max 40
TeeJet® Technologies	AI11003			Min 30	Max 40
	AI8003			Min 30	Max 40
	AI8005			Min 30	Max 40
	TTI11003		Min 20				Max 60
	TTI11004		Min 20				Max 63
	TTI11005		Min 20				Max 60
	TTI11006		Min 20			Max 50
Wilger	DR11010		Min 20		Max 40