Pigweed Emergence (Prostko)

Just a heads up to you and your growers that Palmer amaranth has already emerged in the field (Figure 1).  Consequently, strip-tillage peanut growers who are applying burndown herbicides (Roundup, Gramoxone, 2,4-D) now should seriously consider including a residual herbicide with the burndown.  I would suggest either Valor SX 51WG @ 2 oz/A or Dual Magnum 7.62EC @ 16 oz/A.  Residuals included with the burndown herbicide program should help keep peanut fields pigweed free until planting.

Figure 1. Palmer amaranth emergence at UGA Ponder Farm (Ty Ty), March 19, 2020.

Using Pesticides Wisely (UPW) - 2020 Update (Culpepper and McCann)

Agents, by now you should be aware that all in-person UPW classroom trainings have been cancelled.  Fortunately, several of our locations were able to complete their trainings.  And even more importantly, because of your hard work and a great grower effort, about 95% of those individuals applying Engenia, Enlist One, Enlist Duo, Fexapan, XtendiMax, and Tavium are not required to attend a training session during 2020.  For those still needing to be trained, UGA Extension and the Georgia Department of Agriculture are currently developing an effective approach that will fulfill training requirements.  Dr. McCann will host a Zoom meeting with ANR Extension agents in the very near future to discuss the plan and logistics.  Additionally during this call, we will discuss the registration challenges facing dicamba and what we in Extension can do to assist our growers in making very intelligent decisions during 2020 when applying all pesticides.  Please make sure to attend the call.

2020 Field Corn Hybrid Herbicide Tolerance Information (Prostko)

Some good information to keep in your truck about the tolerance/sensitivity of field corn hybrids to certain herbicides. A very good idea for field corn growers to check this information BEFORE an herbicide application is made.

1) Pioneer

https://www.pioneer.com/content/dam/dpagco/pioneer/na/us/en/products/files/corn/DF_Corn-Hybrid-Herbicide-Response-Ratings-Product-List.pdf

2) Dekalb (had to make my own chart for these)

2020 Dekalb Field Corn Hybrid Herbicide Sensitivity Ratings – Georgia

Hybrid (DKC)	Herbicide Class
	Growth Regulators	Sulfonylureas	Isoxazoles (HPPD)
62-05	C	W	A
62-06	C	W	A
62-08	C	W	A
63-57	A	A	A
64-25	A	A	A
64-32	A	A	A
64-34	A	A	A
64-35	A	A	A
65-18	A	C	A
65-20	A	C	A
66-59	A	A	A
66-94	A	A	A
66-97	A	A	A
67-14	A	A	A
67-42	A	A	A
67-44	A	A	A
67-58	C	A	A
67-70	A	A	A
67-72	A	A	A
68-24	C	A	A
68-26	C	A	A
68-68	A	A	A
68-69	A	A	A
69-16	A	A	A
70-01	A	C	A
70-25	A	A	A
70-26	A	A	A
70-27	A	A	A
70-64	A	A	A

A = Acceptable: Either no adverse effects from the corn product/herbicide combination were noted on any traits or only slight damage could be noted under adverse conditions or herbicide application at higher than label rates. C = Caution:  The corn product/herbicide combination is usually not a problem if sprayed according to label directions, but can result in plant height reductions, stand loss and suspected yield loss under very adverse environmental conditions, high rates or extreme soil pH levels or organic content. Use drop nozzle spraying for postemergence herbicides to avoid interactions. W = Warning: Not advised–this corn product/herbicide combination should not be used under any circumstances.

3) AgriGold (pages 70-71)

http://agrigold.com/Content/pdf/FlipBook/Hybrid-Profile-Guide-2019-20.pdf

EPA's Recent Interim Registration Review Decision About Glyphosate (Prostko)

On January 22, 2020, the EPA released the following document:  Glyphosate - Interim Registration Review Decision - Case Number 0178.  A few excerpts that can be found in this document are as follows:

"The agency used the most current science policies and risk assessment methodologies to prepare a risk assessment in support of the registration reviews of glyphosate."

"The agency concluded that there are no dietary risks of concern for any segment of the population, even with the most conservative assumptions applied in its assessments (e.g. tolerance-level residues, direct application to water, and 100% crop treated)."

"The agency also concluded that there are no residential, non-occupational bystander, aggregate, or occupational risks of concern."

"The EPA concludes that the benefits outweigh the potential ecological risks when glyphosate is used according to label directions."

"The EPA is requiring all glyphosate labels to be updated to modern standards.  The specific components of the label that require updates are as follows:  the maximum application parameters, environmental hazards statement for aquatic use, and clarification on rotational crop timing.  In addition, the agency is providing guidance to glyphosate registrants on acceptable marketing statements." 

"The agency's final registration review decision for glyphosate will be dependent upon an Endangered Species Assessment (ESA), an Endocrine Disruptor Screening Program (EDSP) determination, and a resolution of the Environmental Working Group (EWG) et al. petition (i.e. reduce the tolerance of glyphosate in or on oats from 30 ppm to 0.1 ppm and modify labels to explicitly prohibit pre-harvest use on oats)."

For a copy of the complete report, refer to the following web location:

https://www.epa.gov/sites/production/files/2020-01/documents/glyphosate-interim-reg-review-decision-case-num-0178.pdf

Vegetable Weed Management Circular Update (Culpepper and Vance)

The 2020 finalized circulars are ready: 1) 2020 Broccoli, Cabbage, Cauliflower; 2) 2020 Watermelon, and 3) 2020 Fumigation/Herbicides for Tomato/Pepper/Eggplant.  Squash and sweet potato will not change from 2019.

These circulars should be on-line (www.gaweed.com) by mid-February but if you want one before then or want laminated copies, 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 an address to send them.

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

Georgia Peanut Achievement Club Results - 2018 (Prostko/Monfort)

One of the most beneficial slides that I present at my county meetings is the data collected from the Georgia Peanut Achievement Club (GPAC) growers in regards to the various practices that they use to help manage weeds (Figure 1).  At the last few peanut meetings I have attended, I have been asked for similar information regarding other production practices for other pests.  To that end, I have also attached some data (compiled by Team Monfort) which lists all production inputs for the 2018 GPAC growers (Figures 2 + 3). (Click on pictures for higher resolution)

Dual Magnum vs. Outlook for Tropical Spiderwort Control (Prostko)

At the recent Decatur County Weed Meeting (January 7), I was asked by an attendee about the differences in the control of tropical spiderwort between Dual Magnum (S-metolachlor) and Outlook (dimethenamid-P).  Outlook is the activated isomer of the herbicide formerly sold as Frontier (dimethenamid).  If you are not very familiar with Outlook, it is in the same herbicide family as Dual Magnum (chloroacetamide), has the same mode of action (very long chain fatty acid synthesis inhibitor - WSSA#15), and this active ingredient has been around since the 1990's.  For whatever reason, Outlook never really received much attention during my career but recently BASF has dusted it off. 

My first response to the question was that I did not think that I had any data.  In my defense, you must remember that I have been in Georgia now for more than 20+ years and have conducted 50-70 field trials every year since then.  So the immediate recall of historical data can be challenging, especially for a 56 year old guy who played 12 years of Pop Warner, high school, and D-3 college football long before concussion protocols were common.  However, after reviewing my old files, I discovered some data from 2002 that compared the performance of Outlook to Dual Magnum in a peanut trial conducted in Grady Co.  The results of this trial are presented below (click on graph to download or view a higher quality graph):

It is obvious from this data that Outlook is not quite as effective for the control of tropical spiderwort as Dual Magnum.  However, it is only 1 year's worth of data.  In 2020, I will be looking for a peanut field to conduct some additional spiderwort control research so please keep your eyes open.