Managing Herbicides in Dicamba Tolerant Soybeans (DTS) 

Roundup Ready® Xtend Soybeans, also known as dicamba-tolerant soybeans (DTS) will again be a large portion of the acreage across the region. DTS present the grower with multiple opportunities to control difficult broadleaf weeds. Early post-emergence applications of approved dicamba products in this system have proven to be very effective for management of difficult-to-control weeds. Remember that the DTS system is a weed management SYSTEM, and it begins with effective burndown, followed by residual weed control pre- and post-emergence and ending with effective post-emergence control with the approved dicamba products. Managing the approved in-crop dicamba products, tank mixing approved dicamba products with glyphosate products, and integrating possible use of the many other dicamba products with DTS can be difficult to sort through. The following sections pose some Q&A about managing these herbicides in the DTS system.

Specific Dicamba Products: Current EPA-approved DTS Dicamba Products and Labeling
There are four herbicides approved for use in Roundup Ready® Xtend soybeans. They include XtendiMax® from Monsanto, Engenia™ from BASF, FeXapan™ from Corteva and now Tavium from Syngenta. The approved in-crop dicamba products each have a unique application website. On these websites, there are references including the current product label for each product, approved tank mix partners for each product, a listing of which tank mixes require the addition of a Drift Reduction Agent, a listing of approved nozzles for the dicamba product, and support materials, such as application recordkeeping forms and reference charts to assist in meeting the labelled application requirements. The approved in-crop dicamba products and websites are:
1. Monsanto XtendiMax® - www.xtendimaxapplicationrequirements.com
2. BASF Engenia™ - www.engeniatankmix.com
3. Corteva FeXapan™ - www.corteva.us/products-and-solutions/crop-protection/fexapan.html
4. Syngenta Tavium® - www.syngenta-us.com/herbicides/tavium-application-stewardship

Q&A For Other (Non-DTS System Approved) Dicamba Herbicides
1. There are a lot of other Dicamba products out there, like Banvel, Clarity, Sterling Blue, etc. Can I use these dicamba herbicides IN-CROP with Dicamba Tolerant Soybeans? They contain just dicamba, so the crop will survive, right?
   a. While dicamba-tolerant soybeans are indeed tolerant to any dicamba application, the LABEL IS THE LAW, and once dicamba tolerant soybeans are PLANTED, the only dicamba products that can be applied in that crop are the approved products listed above.

2. So, what about preplant or pre-emergence use of other dicamba products. Can I do that? For example, can I spray Clarity or Sterling Blue pre-emergence?
   a. Other dicamba products CAN be used pre-emergence ahead of dicamba tolerant soybeans. However, you must follow all label restrictions on the product applied. Two key restrictions:
      i. You CANNOT reduce the preplant interval. Non- DTS dicamba products all carry a label that requires a 14-day preplant interval for up to 8 oz of dicamba, and 28 days for 8-16 oz dicamba. These preplant intervals CANNOT be reduced. Only the approved dicamba products have a zero-day preplant interval.
      ii. You CANNOT Increase the rate of the non-DTS system dicamba. You cannot increase the application rate above the rate on the label, simply because the crop will be dicamba-tolerant. Again, you MUST follow the label of the product being applied.

3. If I did not get a burndown done ahead of planting dicamba tolerant soybeans, can I still spray dicamba on those soybeans after planting?
   a. YES, provided the dicamba you apply is on the of the four approved dicamba products: Engenia, XtendiMax, FeXapan or Tavium. These are the ONLY dicamba-containing products with approved reduced/zero pre-emergence intervals.

4. Can I use Status as a burndown herbicide, or use it in-crop?
   a. NO. Status contains not only dicamba, but also another herbicide called diflufenzopyr. Diflufenzopyr increases the activity of dicamba in the plant. Diflufenzopyr also has some herbicidal activity itself and will severely damage DTS, like it does to RR, LL or conventional soybeans.

5. Are DTS tolerant to other auxin herbicides, like 2,4-D, including Enlist, Starane or Stinger?
   a. NO. Dicamba tolerant soybeans for 2019 are tolerant only to dicamba and to glyphosate.

Q&A: Understanding the glyphostate herbicides Approved For The DTS System
1. Dicamba Tolerant Soybeans are all Roundup Ready. So that means any glyphosate product I have on hand can be used with the approved dicamba product, correct?
   a. NO. Each dicamba product approved for use in dicamba-tolerant soybeans has a unique listing of approved glyphosate products. Refer to the specific website for approved tank mix partners.

2. If the glyphosate I want to use is not on the list for the specific approved dicamba I want to use, is it OK to still use that product?
   a. NO, but this depends on the usage pattern. If the glyphosate you want to use is not on the approved list, it means it CANNOT be applied in the same tank mix as the dicamba product in question. However, if the glyphosate in question is applied in a separate application that is NOT tank mixed with the approved dicamba, the product may be used.
   b. For Example, XtendiMax only allows certain K-salt glyphosate products to be applied with it. You cannot tankmix an IPA salt glyphosate with XtendiMax. However, Engenia allows K-Salt as well as IPA salt glyphosates to be tank mixed.

3. RT3 from Monsanto is a common glyphosate, and I do not see it anywhere in the dicamba product websites. There are some other glyphosates that are not listed as well. Why are they not listed?
   a. There may be many reasons for this. The specific glyphosate may not have been submitted for testing by the dicamba registrants.
   b. Another possible reason is that the specific glyphosate may contain additives or simply a base chemistry that adversely affects the drift reduction technology of approved dicamba products. For example, XtendiMax cannot be tank mixed with IPA salt glyphosates for this reason.

2019 Dicamba Tolerant Soybeans – Approved Glyphosate Products
Note on Usage Rates: A common usage rate for glyphosate products is 40 oz/a. In the DTS System, however, you are limited to 1.125# acid equivalent (AE), which often equilibrates to 32 oz/a maximum product use rate per application. XtendiMax simply states a 32 oz/acre/application maximum for all products, Engenia uses the 1.125# AE terminology

1. XtendiMax or FeXapan: Approved Glyphosates
• Abundit® Edge
• Bullseye HL-K
• Honcho® K6
• Mad Dog® K-6
• Roundup PowerMAX® II
• Roundup PowerMAX®
• Roundup WeatherMAX®
• Sequence
• EnvyTM K-Six
Notes:
1) All the above are potassium-salt (K-Salt) glyphosates
2) When ANY glyphosate above is mixed with XtendiMax or FeXapan, an approved DRA must be added to the tank mix.

2. Engenia: Approved Glyphosates
 

Abundit® Edge Envy™ Intense Makaze Yield Pro®
Barbarian Max™ Envy™ Six Max Makaze®
Buccaneer® Gly Star® K-Plus Mountaineer™ 6 max
Buccaneer® 5 Extra Glyfos® X-Tra Roundup PowerMax®
Buccaneer® Plus GlyStar® 5 Extra Roundup PowerMax® II
Bullzeye™ GlyStar® Plus Roundup WeatherMax®
Bullzeye™ HL-K Honcho® K6™ Sunphosate® 41%
Cornerstone® 5 Plus Mad Dog® Tomahawk 4™
Cornerstone® Plus Mad Dog® 5.4 Tomahawk 5™
Credit® 41 Extra Mad Dog® K6  
Credit® Extreme Mad Dog® Plus  


Notes:
1) There are multiple glyphosate salts approved among these products.
2) Only Abundit Edge requires the use of a Drift Reduction Agent when tank mixed with Engenia only.