Troubleshooting (Prostko)

Now that we are about to head into the busy planting season, extension agents will likely be spending more time in the field troubleshooting problems.  As an extension specialist, I am always more than happy to help with any problem. However, it can often be very frustrating for me (and other specialists) to get sent a picture(s) with no more information than "Do you think this is herbicide injury?"  Despite my ever whitening hair, there is still plenty that I do not know and the diagnosis of crop injury is often very complicated.  Thus, before sending me a text or e-mail (I prefer e-mail pics since they are easier to see), try to get as much information as possible about the problem.  For example:

Crop:
Variety/Hybrid:
Planting Date:
Herbicide Application Dates:
Previous Crop and Herbicides Applied (what and when):
Current Fertility Program:
Other Pesticides/Products Applied:

It would also be extremely beneficial for agents to collect soil fertility and nematode samples, since nutrient deficiencies and nematode injury can often resemble herbicide injury.  Often times, the best way to solve a problem is to rule out what it is not.  For the record, many "herbicide injury" problems that I have been involved in over the last 20 years turned out to be nematode or fertility problems.

Here are just a few good web-sites for help in diagnosing field problems:

Herbicide Injury Symptoms on Corn and Soybean (Purdue)
https://www.btny.purdue.edu/Extension/Weeds/HerbInj2/InjuryHerb1.html

Peanut Herbicide Injury Guide (TAMU)
http://publications.tamu.edu/PEANUTS/PUB_peanuts_Peanut%20Herbicide%20Injury%20Symptomology%20Guide.pdf
(Special Note: I co-wrote this publication earlier in my career and since that time, I have proven that shoot inhibitor herbicides (Dual Magnum, Warrant , Zidua) do not cause peanut  J-rooting (page 5).

Herbicide Injury Data Base (University of Arkansas)
https://plants.uaex.edu/herbicide/

Herbicide Damage to Cotton (TAMU)
http://cotton.tamu.edu/Photos/herbicide_injury/index.html

Nutrient Deficiencies and Application Injuries in Field Crops (Iowa State)
https://crops.extension.iastate.edu/files/article/nutrientdeficiency.pdf

Lastly, please remember that I have always and will always answer any phone call, text, or e-mail I receive from extension agents in a timely matter! 

Vegetable Weed Management Circulars are Available! (Culpepper and Vance)

The following weed control circulars are ready: 1) Broccoli, Cabbage, Cauliflower; 2) Yellow and Zucchini Squash, 3) Watermelon, 4) Methyl Bromide Alternatives, and 5) Sweet Potato.

For those not familiar with our circulars, they are each two pages with a programs approach for managing weeds while mitigating herbicide or fumigant injury.

If you would like a copy prior to them being uploaded on our web site (www.gaweed.com) in March of 2019, do the following:

E-mail Jenna Vance at jcsmith3@uga.edu and ask for one of the following options:

Option 1: Request laminated circulars to be mailed to you. Provide the number of circulars for each crop that you would like and provide and address to send them.

Option 2: Request a pdf version.  An e-mail response will provide the PDF as an attachment.

Using Pesticides Wisely (UPW) Pesticide Credit Hours and Neighboring State Training Programs (Stanley Culpepper - UGA and Tommy Gray - GDA).

Agents, several of you have been asking questions regarding the UPW trainings so we thought it would be best to share with everyone.

1.  How many hours of pesticide credit will be offered at the UPW training?   

The answer is 2 for commercial or 2 for private.  Agents do not have to do anything in regards to pesticide credit hours, we have it all covered.

2. If one of my growers/applicators takes the dicamba training in a neighboring state will that cover them for Georgia?  

The answer is NO. Anyone who purchases and applies Engenia, FeXapan, or XtendiMax in Georgia must attend our UPW training; just as importantly, they must actually turn in the registration form for attending the meeting. The fact that other trainings from our neighbors will not meet Georgia’s requirements has nothing to with the quality of their training. Rather, it reflects the complicated nature of trying to get everyone in Georgia trained and then getting the appropriate information documented on GDA’s web-site in a 3 month time frame. 

Xtendimax, Engenia, Fexapan (Culpepper)

Agents you already have information regarding the new auxin herbicide requirements in various ways; however, one of our industry partners asked me to help him with a few points to share with his contacts.  I thought you might benefit so they are provided below. Also, we conducted our first UPW training and training for the 2 year certified applicators license for XtendiMax, Engenia, and FeXapan in Tifton on Wednesday, January 30.  The crowd for BOTH trainings was enormous. The number of people getting a license were at least four times more than I had expected……………….get prepared!

XtendiMax, Engenia, and FeXapan

New Regulations for 2019

1) A pesticide license is required to purchase or apply these products.

2) All applicators must be trained through UGA's Using Pesticides Wisely (UPW).

3) Can only apply through 60 days after planting cotton or 45 days after planting soybeans.  

4) Can only make up to 2 POST applications in cotton and soybeans.

5) Can only apply between 1 hour after sunrise and 2 hours before sunset (wind still has to be between 3 and 10 mph). 

6) Updated record keeping within 72 hours and add planting date.

7) Labels suggest to test for spray solution pH and add a buffering agent if solution pH is less than 5. 

8) Do not apply when wind is blowing in direction of sensitive crops and/or residential areas. 

9) If there are no sensitive crops or residential areas downwind, then downwind buffers remain. 110 ft but there is a new 57 ft omni-directional (all sides) buffer required in certain counties where endangered terrestrial dicot plants grow (visit www.epa.gov/espp/ to understand if you have endangered species near you. 

10) Do not apply if expected rainfall within 24 hours of application could exceed soil field capacity.

Enlist One and Enlist Duo

1) All persons in charge of application must be trained.

Yellow Nutsedge/Cadre Resistance (Prostko)

In September 2017, after doing some preliminary screening (Figure 1), we collected yellow nutsedge tubers from a peanut field that were a strong suspect for resistance to Cadre (imazapic).  We sent the tubers to BASF for further greenhouse testing and just got back the results.  Unfortunately, it looks like this population of nutsedge has developed resistance to Cadre (Figures 2 and 3).  On the positive side, it does not appear to have developed cross-resistance to Sandea/Permit (halosulfuron).  In order to protect the grower's privacy, I would prefer not to reveal the exact location of this field at this time.  

Assuming adequate funding is obtained , I will be working very closely with our new teaching/research weed scientist on the main campus in Athens, Dr. Nick Basinger, to further investigate this issue.  Dr. Basinger recently replaced Dr. Bill Vencill.  If you are already aware of or become aware of peanut fields where Cadre has been used for yellow nutsedge control with less than optimum results, please let us know so that tubers can be collected from the field.   At this point in time though, I believe that this discovery of resistance is most likely an isolated case.  

Here are a few things to consider in regards to this issue, especially how it compares to the herbicide-resistant Palmer amaranth problems that we have been dealing with since 2004:  

1) At this point in time, only 1 case of herbicide-resistance in yellow nutsedge has been officially confirmed world-wide.   In 2013-2014, researchers from Arkansas confirmed halosulfuron resistance in a yellow nutsedge population collected from a rice field.  For comparison, 61 cases of herbicide resistance in Palmer amaranth have been confirmed.  

2) In Georgia, Cadre was first commercialized for use in peanut in 1996 so it took more than 20 years for this resistance to occur in yellow nutsedge.  It took roughly 3-4 years for glyphosate resistance to evolve in Palmer amaranth after the introduction of RR soybeans (1996) and RR cotton (1997).

3) The GA problem site is a dryland field where peanuts were grown for 5 continuous years and Cadre was used every year (for economic reasons).  This is atypical of the normal crop rotation sequences used by most Georgia peanut growers.  Unlike glyphosate, Liberty and PPO herbicides, Cadre is not applied to fields on a yearly basis. 

4) Yellow nutsedge can produce a large amount of seed but seed is not the primary propagation mechanism.  Some research has shown that <1% of yellow nutsedge seeds can develop into viable seedlings.  Seed is the only propagation mechanism for Palmer amaranth.  

5) The primary mechanism of  yellow nutsedge propagation is through tubers.  In Georgia, a single yellow nutsedge plant, growing without competition in a bareground area, produced 700 tubers after 6 months of growth.    

6) The primary mechanism of yellow nutsedge tuber dispersion in fields is through normal field operations such as tillage/disking and equipment movement (i.e. human action).   

7) Foraging and soil disturbance from feral hogs has been reported to promote the long-term population maintenance of yellow nutsedge.  

8) There could be also be some slight dispersion from waterfowl that prefer yellow nutsedge tubers as a food source (i.e. ducks, geese).  However, a recently published study from Missouri reported that no intact nutsedge tubers were recovered from mallard ducks in 8 feeding trials.  In these same feeding trials, 26% of Palmer amaranth seeds were viable after feeding.

Figure 1.  Cadre and Sandea field screen on suspect resistant yellow nutsedge population in Georgia, 2017.

Figure 2.  Suspect resistant yellow nutsedge population treated with Cadre 2AS @ 32 oz/A (8X rate), 21 DAT.

Figure 3.  Susceptible yellow nutsedge population (left) and suspect resistant population (right) treated with various rates of Cadre 2AS - 28 DAT.

Auxin Training Requirements for 2019 (Culpepper)

 Agents, see information below regarding the use of Engenia, FeXapan, XtendiMax, Enlist Duo or Enlist One for 2019. This is official and approved by the Georgia Department of Agriculture. You will also be sent this information through the normal chain of command. For questions regarding UPW trainings contact me. HOWEVER, for pesticide license questions contact Dr. McCann!!!
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AUXIN TRAINING REQUIREMENTS: GEORGIA 2019

NOTICE! U.S. EPA-Industry mandated label changes to dicamba products Engenia, FeXapan, and XtendiMax are now effective for the 2019 growing season.

Engenia, FeXapan, XtendiMax

1. As mandated by federal labels, one must hold a private or commercial pesticide applicator license to purchase and use these restricted use herbicides. Use is limited to ONLY those persons holding a private or commercial applicator certification.* It is no longer permissible for non-certified applicators to apply these products under the direct supervision of the certified applicator.
2. Prior to applying these products in 2019, ALL applicators must be trained according to the federal labels. In Georgia, applicators must complete the 2019 Using Pesticides Wisely classroom training. If you attended this training in 2015, 2016, 2017, or 2018, you must re-take the training in 2019.
3. Industry applicator trainings are encouraged and beneficial; however, they will not fulfill Georgia’s requirement for auxin training.
4. Each label requires certified applicators to document application information. Forms have been designed to help with this challenge and can be found at your local UGA Extension office, from the herbicide registrant, or at http://agr.georgia.gov/24c.aspx

Enlist Duo or Enlist One

1. All persons in charge of in-crop applications (planting through harvest) of Enlist Duo or Enlist One in Enlist cotton or soybean must complete the Using Pesticides Wisely classroom training. If you attended this training in 2015, 2016, 2017 or 2018, you must re-take the training in 2019.


*For those seeking certification as a private pesticide applicator:

Initial certification to become a certified private pesticide applicator requires the completion of an interactive, online Private Applicator training program administered by University of Georgia Extension (http://extension.uga.edu/programs-services/pesticide-safety-education/private-applicators.html). The online training and testing requires a total time commitment of approximately 4-5 hours and a $25 fee. Applicants MUST be able to read and understand a label. Application of auxin herbicides carries certain inherent risks associated with off-target movement. Anyone applying them should be well-trained, have a clear understanding of the potential for off-site damage, and be able to make complex decisions on when and where these products should be applied. Applicants and their employers should carefully consider who is capable of applying these products safely before beginning the certification process.


USING PESTICIDES WISELY TRAINING DATES/TIMES/LOCATIONS WILL BE PROVIDED IN MID-JANUARY 2019

Protecting Endangered Species – U.S. EPA (Culpepper, UGA and Tommy Gray, GDA).

Agents see the information and link below regarding the new dicamba labels and buffers, provided by Region IV EPA. The web site is interesting and, I think, predicts the future for ALL pesticides in protecting endangered species.

“Please be advised, OPP has posted the additional endangered species restrictions related to dicamba on The EPA Bulletin’s Live! Two website here https://www.epa.gov/endangered-species/bulletins-live-two-view-bulletins. All states in Region 4 have been affected. Please check the website to see the affected Pesticide Limitation Use Areas in your state. The additional restrictions include the following: “In combination with the 110 foot in-field wind-directional spray drift buffer, a 57 foot omnidirectional infield buffer is required to protect federally listed threatened and endangered species. Non-sensitive areas, defined below, may be included as part of the buffer. Non-sensitive areas: The following areas may be included in the buffer distance calculation when directly adjacent to the treated field edges: 1. Roads, paved or gravel surfaces, mowed and/or managed areas adjacent to field such as rights of way. 2. Planted agricultural fields containing: corn, cotton, and soybeans. 3. Areas covered by the footprint of a building, silo, or other man made structure with walls and or roof.”

As of today, the following 6 counties in Georgia are affected by the additional 57' omni-directional buffer dicamba restrictions:  Decatur, Dooly, Floyd, Mitchell, Seminole, and Worth.  This could change in the future so it is important that the web-site be monitored on a regular basis in order to maintain compliance.