Pennsylvania: What’s New for Agronomic Weed Control in 2020?

Planting and applying pre-emerge herbicide. ©Debra L Ferguson

Planting and applying pre-emerge herbicide. ©Debra L Ferguson

Product/Label/Pipeline Updates

As in the recent past, there are absolutely no new herbicide modes of action. All the newer herbicide products are simply new premixes or revised formulations of existing active ingredients.

There are not many new products to discuss for this upcoming growing season. But here are a few products, label updates, and products in the pipeline to consider:

  • Acuron GT (bicyclopyrone + mesotrione + s-metolachlor + glyphosate; groups 27, 15, 9; Syngenta) is an experimental herbicide premix that will be used in corn. It does not contain atrazine and will have a similar utility as Halex GT. It should be available by 2022.
  • Authority Edge (sulfentrazone [Spartan] + pyroxasulfone [Zidua]; groups 14, 15; FMC) has similar active ingredients as Authority Supreme but has a higher sulfentrazone load for use in soybean in 2020. It will be soil-applied and have activity on both annual grasses and broadleaf weeds at 7-9 fl oz/A.
  • Axial Bold (pinoxaden + fenoxaprop; group 1; Syngenta) is a newer herbicide combination that provides postemergence control of several weedy grasses in wheat and barley. It will replace Axial XL. Keep in mind, some populations of annual ryegrass, foxtail, and barnyardgrass are resistant to this mode of action in our region.
  • Bayer is working on a new experimental, high load, unique adjuvant, glyphosate formulation (MON 301107) which should be available in 2021.
  • Gramoxone 3SL (paraquat; group 22; Syngenta) is a new, high-load formulation (from a 2 pound to a 3 pound active ingredient load per gallon). Thus, lower product rates will be used. It will be available for the 2020 growing season.
  • Perpetuo (pyroxasulfone + flumiclorac [Resource]; group 15, 14; Valent) is an experimental premix for annual grass and broadleaf control in soybean.
  • Pixxaro (halauxifen [Elevore] + fluroxypyr [Starane Ultra]; group 4; Corteva) is a new premix for broadleaf weed control in wheat and barley.
  • Rinskor active is a new herbicide called florpyrauxifen (group 4; Corteva) which is in the same family as Elevore. When available, Rinskor active can be used in pastures containing white clover. It has activity on certain broadleaf and a few grassy weeds. DuraCor is a premix of Rinskor active and Milestone. But other premixes will likely follow in the upcoming years.
  • Shieldex 3.33SC (tolpyralate; group 27; SummitAgro) is a new, low-use rate (1 to 1.35 fl oz/A), HPPD-herbicide that controls annual grasses and broadleaves postemergence in field and sweet corn. It is very similar to Armezon or Impact. It will typically be tankmixed with atrazine to improve the control spectrum.
  • Tough 5EC (pyridate; group 6; Belchim) is an old active ingredient and is making a comeback. The last time it was used in corn and soybean in the US was in 2007. However now that Belchim, a Belgian chemical company has this product they are trying to get it registered in more crops here in the U.S. It is a post, contact herbicide and controls broadleaf weeds such as lambsquarters, pigweeds, and nightshade. We are not sure when it will be registered for use again in our area.
  • Zidua and Anthem Maxx can now be applied to soybean up to V6 growth stage.

Paraquat update

Anyone using products containing paraquat (i.e. Gramoxone and all other generic formulations) that were manufactured after November 14, 2019 must complete an EPA-mandated training before application.

The following are items related to the new label for paraquat products:

  • Only certified applicators, who successfully completed the paraquat-specific training, can mix, load or apply paraquat
  • No longer allow application “under the direct supervision” of a certified applicator; registered technicians cannot apply
  • Restricting the use of all paraquat products to certified applicators only
  • Applicators must repeat training every three years
  • The EPA required video training is at “How to Safely Use and Handle Paraquat-Containing Products” (users must create an account with user name and password). For those who are unable to do the training online, EPA is working on another non-web-based training format which should be available by January 2020.
  • Go to the EPA webpage “Paraquat Dichloride Training for Certified Applicators” for more information and frequently asked questions.

Keep in mind, any paraquat-containing products manufactured before November 14, 2019 can be handled and applied as directed by the label attached to the container and without the mandated EPA training.

In addition to the training, EPA requires that paraquat products be contained in a closed system. Over the next year or so, manufacturers will begin placing special lids on 2.5-gallon jugs and a necessary adaptor/receptacle will need to be installed on your sprayer in order to pour this herbicide into the sprayer tank.

These new jug caps cannot be removed or opened by hand. Despite the special lid, partial amounts of product can still be dispensed from the jug, as volume marks and a transparent viewing strip will be on the container.

Mini bulk tanks will also have special connectors on hoses to maintain a closed system into the sprayer tank. More details will be released once these lids and adaptors become more widely available.

Newer soybean technologies

Understanding the differences:

With all the newer soybean technologies on the market, it can be somewhat confusing to know the differences between them. Make sure you know the differences between the unique variety options before you purchase.

Also, consider that other “standard herbicides” that are labeled for use in soybeans still can be used with any of these as well. Here is a quick overview of their trait packages and some related herbicides:

  • Roundup Ready 2 Yield soybeans are tolerant to glyphosate only.
  • Roundup Ready 2 Xtend soybeans are resistant to both glyphosate and dicamba products labeled for this use.

Last year, the EPA re-registered the Xtend-specific dicamba products until Dec. 2020. Engenia 5L (dicamba-BAPMA salt; BASF), Xtendimax 2.9L (dicamba-DGA with Vapor Grip Technology; Bayer) and FeXapan 2.9L (dicamba-DGA plus Vapor Grip Technology; Corteva) are the only three dicamba-only herbicides that can be used in Roundup Ready 2 Xtend (dicamba-tolerant) soybeans.

Each of them contains the group 4 herbicide dicamba and are now classified as “Restricted Use Pesticide” (RUP) and thus require special dicamba-specific training annually to purchase and apply them. For more information and other details about application, see:

Tavium 3.39CS (dicamba + s-metolachlor [Dual Magnum]; groups 4 and 15; Syngenta) and Engenia Pro 4.5SC (dicamba + pyroxasulfone [Zidua]; groups 4 and 15; BASF) are premixes and will provide post broadleaf control from dicamba and residual annual grass and broadleaf control from Dual/Zidua in Xtend soybeans.

Their prime targets will be Palmer amaranth and waterhemp. Tavium is registered for use in 2020, however Engenia Pro will likely be marketed in 2021.

  • XtendFlex soybeans are resistant to glyphosate, dicamba, and Liberty. XtendFlex beans have been fully registered in the US for a couple of years now and has export approval everywhere but Europe. Assuming the EU approves soon, a limited amount of XtendFlex beans will be available for sale in the late spring of 2020. Otherwise, a large supply should be available for the 2021 growing season.
  • Enlist E3 varieties are registered for use and are resistant to glyphosate, certain 2,4-D products registered for this use, and Liberty. Enlist Duo 3.38L and Enlist One 3.8L are two 2,4-D choline salt containing herbicides from Corteva for use in Enlist crops. Enlist One has the single active ingredient of 2,4-D choline and Enlist Duo also contains glyphosate. No other types of 2,4-D formulations are expected to be labeled for use over-the-top on Enlist crops. For more information refer to the Enlist application website.
  • LibertyLink varieties are resistant to Liberty and other glufosinate-containing products.
  • LibertyLinkGT27, sometimes referred to as LLGT27 beans, are resistant to Liberty, glyphosate, and Alite27 or isoxaflutole the same active ingredient in Balance Flexx. Alite27 is not yet registered for use in LLGT27 beans yet but it is expected soon.
  • GT27 soybeans are only tolerant to glyphosate and Alite27 but not to Liberty.

Soybean acres:

Since Xtend soybean technologies are being used more often over the past year, here is brief review. In the 2019 growing season, there were approximately 85 million acres of total soybeans planted in the U.S. which is down from over 90 million in 2018. About 55 million or so acres were Xtend in 2019.

In some areas of the country, up to 80% of the soybean areas were planted to an Xtend variety and at least 30 million acres were sprayed with dicamba. The exact number of acres that either a pre or post application of dicamba was sprayed onto is not known, however, in most areas it was a rather large percentage.

In Pennsylvania, there were about 600,000 acres of soybeans planted in the state, and of those, about 75% were Xtend. But only about 25% or so were actually sprayed with dicamba. Most dicamba applications were sprayed by private applicators.

Many commercial applicators did not apply dicamba to Xtend soybeans this past season for various reasons, but mostly due to the potential for liability if drift occurred.

Expectations for the 2020 growing season are that the acres of Xtend soybeans will be about 75% of the acres. While around 20% will be planted to either Enlist E3, LLGT27, or LibertyLink varieties and the remaining acres will be planted to some other soybean varieties.

DriftWatch by FieldWatch is now available to use in Pennsylvania. It is a free, online Voluntary Specialty Crops Registry … so applicators know to be cautious when spraying in a certain area. The stewardship tool allows for improved communication and collaboration between producers of specialty crops and pesticide applicators using a technology platform where producers can map their sites and provide contact information to pesticide applicators through an online mapping system.

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