Spring Herbicide Applications on Winter Wheat – Part 2 Labeled Herbicides

Source: Purdue University (Edited)

If weed infestations are severe enough to require a herbicide application, the use of liquid nitrogen fertilizer solution as a carrier is a popular option for applying herbicides and topdressing the wheat crop in a single pass over the field.  Caution should be taken when using a liquid fertilizer as a herbicide carrier as moderate to severe crop injury can result, especially in saturated conditions.  Many post applied wheat herbicide labels allow for liquid nitrogen carriers, but require different rates and types of surfactants than if the herbicide was applied with water as the carrier.  Table 1 includes precautions to be taken when applying wheat herbicides using liquid fertilizer as a carrier; further details and directions can be acquired from the herbicide label.

Another consideration growers should take into account when planning early spring herbicide applications is the plant back restrictions to double crop soybeans.  A large percentage of the herbicides listed in Table 1, especially those with activity on Ryegrass and Brome, have soybean plant back restrictions greater than the typical three month time period between spring applications and double crop soybean planting.  The soybean plant back restrictions greatly reduce the number of options available to wheat producers who double crop soybeans after wheat.  Refer to Table 1 for more specific plant back timing restrictions.Click Here For Complete Table

Spring Herbicide Applications on Winter Wheat – Part 1 Growth Stages

Source: Purdue University (Edited)

The winter is finally winding down and we are bound to have warmer days and spring in the near future. As we look towards the warmer weather there a few field activities that are going to start quickly, including winter wheat greenup herbicide applications and winter annual weed burndown applications in no-till fields. There are few things to keep in mind as these activities are added to the calendar. Many wheat producers, especially in the southern regions of Indiana will soon be or already are topdressing their wheat.  Those looking into topdressing need to also be scouting for weeds and determining if a herbicide application is necessary on any existing winter annual weeds.  The following information will outline winter annual weeds to look out for, weed scouting tips, crop stage restrictions, and herbicide recommendations.

Some common broadleaf weeds to scout for in your winter wheat are dandelion, purple deadnettle, henbit, chickweed, Canada thistle, and wild garlic.  These winter annual species that emerge in the fall can remain relatively inconspicuous through the winter and become competitive and troublesome during the spring if not controlled early in the spring.  Summer annual weeds such as ragweed will be of less concern in the early spring and will be outcompeted by the wheat crop if managed properly.  Grass weeds to be aware of and scouting for are: annual bluegrass, annual ryegrass, cheat, and downy brome.

Determining the severity of weed infestations in your wheat fields is key in determining the necessity of a herbicide application.  As with all agronomic crops, you should scout your entire field to determine what weed management practices need to be implemented and determine any areas of severe weed infestations.  Wheat fields that contain uniform infestations of at least one broadleaf weed and/or three grass weeds per square foot should be taken into consideration for a herbicide application to avoid yield loss and harvest interference problems.  Some fields that have less uniform infestations, but rather pockets of severe infestation should be managed to reduce weed seed production and future infestations.

When determining your herbicide program for spring applications, the stage of the wheat crop should be considered.  The majority of wheat herbicides are labeled for application at certain wheat growth stages and some commonly used herbicides have very short windows in which they can be applied.  The popular broadleaf weed herbicides 2,4-D and MCPA are efficient and economical, but can only be applied for a short period of time between tillering and prior to jointing in the early spring.  Wheat growth stages and herbicide timing restriction are outlined in Figure 1 above.

Pesticide & Fertilizer Re-certification

Time is running out – Check the Expiration date on your pesticide and fertilizer license!

If you need your Pesticide and Fertilizer License Re-certification this year, our final re-certification class in Knox County will be held on March 27, 9 a.m. in the conference room of Advantage Ag and Equipment, 1025 Harcourt Road, Mount Vernon. All categories will be offered. There is a $35 class fee.

What’s Legal to Apply to the LL-GT27 Soybean – The (maybe almost) Final Story

by: Dr. Mark Loux, OSU Extension

Having to issue a retraction to previous C.O.R.N. article where we thought we had it right is always fun.  About a month ago we ran an article that covered the legality of POST glyphosate and glufosinate applications to the LL-GT27 soybean, which is resistant to both herbicides.  The issue at that time was the legality of applying a mix of both herbicides, based on questions we had received.  Cutting to the quick, our conclusion was that because it was legal to apply the mixture since both herbicides could legally be applied and labels did not prohibit mixing.  We were naïve apparently, because that article caused the issue over whether it was actually legal to apply glyphosate to the LL-GT27 soybean to be raised.  Since then, ODA, USEPA, and the companies who are the involved registrants have been working to come to a solution that clarifies this issue and keeps us all moving forward toward a resolution.  The issue here seems to be this – wording on most glyphosate labels specifies application is allowed to “Roundup Ready” and “Roundup Ready 2 Yield” soybeans, and since the LL-GT27 soybean is not designated as such, those glyphosate products could not legally be applied.  After a month of deliberation, the USEPA issued some guidance which took the form of the following:

“Users of pesticide products containing glyphosate should refer to the pesticide product labels of herbicide products containing glyphosate for the specific registered uses on pesticide-resistant crops such as soybeans with glyphosate-resistant trait(s).  Regardless of the herbicide product name (brand name), if the label of the glyphosate product states it is for over-the-top (post-emergent) use on glyphosate-resistant soybeans, and it is not otherwise restricted by other label statements/directions for use, it can be used on any soybean that has a glyphosate-resistant trait.  However, if the label of the glyphosate product states it is for use on crops such as soybeans, with specific glyphosate-resistant traits by name, then the glyphosate product can only be used on those crop(s) with those traits specifically identified on the label.  Ultimately, growers and commercial applicators must comply with the entirety of the pesticide label.  Please let us know if you have any questions.”

Questions – yes – excuse us while we look for the head scratching emoji.  We can try to interpret in real-life speak.  Here’s what it comes down to:

– the important part of the glyphosate label here is the use-specific directions, or the section within the larger “Roundup Ready” part of the label that deals with soybeans.

If the soybean section of the glyphosate product label does not mention specific genetics by trade name, but just the wording “glyphosate-resistant” or “glyphosate-tolerant”, then it is legal to apply that product to the LL-GT27 soybean.

– if the soybean section of the label restricts use to certain genetics by trade name –  “Roundup Ready”, “Roundup Ready 2 Yield”, etc, then it would not be legal to apply to the LL-GT27 soybean.

– if the wording on the label is along the lines of “For Use on Soybeans with the Roundup Ready gene”, or similar wording with other specific genetics, it would not be legal to apply to the LL-GT27 soybean.

Our not exhaustive search through glyphosate product labels indicates that most if not all do not contain any wording about “glyphosate tolerance” in the soybean section, and indicate use is specifically on “Roundup Ready” or “Roundup Ready 2 Yield” or “Soybeans with the Roundup Ready gene”.   This includes Roundup PowerMAX, Durango DMA, Abundit Edge, Credit Extreme, and Cornerstone to name a few.  Manufacturer reps with a glyphosate product label that varies from this are free to contact us so we know.

The inability to use glyphosate on the LL-GT27 soybean affects primarily growers who bought it for the genetics or other traits and not the LibertyLink trait, who might have planned to use only glyphosate POST.  Most of the utility of this soybean on problem broadleaf weeds comes from the LibertyLink trait though (and it’s definitely legal to apply glufosinate POST).  There’s plenty of generic clethodim around to help out with grass.  We assume label language will adapt over time to take care of the glyphosate issue.  We’re not even sure this issue would have come up if we hadn’t tried to clarify the tank-mix legality and stepped right in it.  There appeared to be some confusion in the field about this though, with different stories being told, and better to just clear it all up way in advance of the season.  Stay tuned for the next chapter.  Offer void where not legal.  Legality may vary by state.  Your mileage may vary.  Side effects may include confusion, apathy, anger, and spontaneous profanity.

The LL-GT27 soybean – what’s legal?

Source: Dr. Mark Loux, OSU Extension

We are starting to see the availability of soybean varieties with more than two herbicide resistance traits, which can expand the herbicide options, improve control, and allow multiple site of action tank mixes that reduce the rate of selection for resistance.  One of these is the Enlist soybean, with resistance to glyphosate, glufosinate, and 2,4-D.  As of this writing, full approval for the Enlist soybean is still being held up by the Philippines (because they can apparently).  The other is the LL-GT27 soybean, which has resistance to glyphosate, glufosinate, and isoxaflutole (Balance).  There is no label for use of isoxaflutole on this soybean yet, but it is legal to apply both glyphosate and glufosinate.  In Ohio, as long as neither label prohibits applying a mixture of two herbicides labeled for a specific use, it’s legal to apply the mixture.  So, it’s also legal to apply a mixture of glyphosate and glufosinate to the LL-GT27 soybean.  There is no label that actually mentions or provides guidance for this mixture, which does not affect legality, but could affect who assumes liability for the recommendation to apply a mixture if that matters to you.  Some seed companies are making the recommendation for POST application of the mix of glyphosate and glufosinate to the LL-GT27 soybean in printed materials.  Our interpretation after discussion with ODA, is that these materials are essentially supplements to labels, and so the seed company would assume some liability for the recommendation.

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New Requirements For Dicamba Use

Revised label and new training required before use in 2019

If you are planning to use Engenia (BASF), XtendiMax (Monsanto) and FeXapan (DuPont) in 2019 there are major changes to the labels for the products that you need to be aware of.  The biggest change is only license applicators can purchase, mix, load, apply or clean application equipment.  Previously these tasks could have been completed by an unlicensed applicator if they were “supervision by a certified applicator”.  Below is the ODA news release pertaining to the new regulations.

REYNOLDSBURG, Ohio (Jan. 16, 2019) – The Ohio Department of Agriculture (ODA) is reminding farmers of revised labels and new training requirements for applicators who intend to use dicamba herbicide products this year. In October 2018, U.S. EPA approved revised labels for the three dicamba products that are labeled for use on soybeans: Engenia (BASF), XtendiMax (Monsanto) and FeXapan (DuPont).

“Like any other product, we want to ensure licensed applicators are properly following label directions as they get ready for this growing season,” said Matt Beal, chief of the ODA Division of Plant Health. “This not only helps ensure the safe use of pesticides, it also helps prevent misuse and mishandling.”

The manufacturers of these dicamba products also agreed to additional requirements for their products. Some of the requirements include:

  • 2019 labels supersede all prior labels for these products. Applicators must obtain a copy of the new label and must have that label in their possession at the time of use
  • Only certified applicators may purchase and apply the products
    • Those operating under the supervision of a certified applicator may no longer purchase or apply.
    • Anyone who mixes, loads or cleans dicamba application equipment must become licensed.
    • ODA will host additional “Dicamba Ag Only” exams in February and March for those looking to become a certified applicator. Visit agri.ohio.gov for more details.
  • Applicators must complete dicamba-specific training
  • Increased recordkeeping requirements
  • Wind speed restrictions
  • Temperature inversion restrictions
  • Sensitive/susceptible crop consultation
  • Spray system equipment clean-out

More details on these revisions can be found in the attached fact sheet. Applicators looking for a list of ODA-approved trainings can visit www.agri.ohio.gov. For questions, applicators can contact the ODA Pesticide and Fertilizer Regulation Section at 614-728-6987 or pesticides@agri.ohio.gov.

Developing a long-term comprehensive weed management system – Part 2

Source: Iowa State University, (Edited)

Post 2 of a 4 post series.

As the end of the year approaches and we reflect on the 2018 growing season we need to look at what changes or improvements we need to make in our production plans for 2019.  Herbicide resistant weeds are continuing to create problems.  New, very invasive and harmful weed species (Palmer Amaranth and Waterhemp) are now prevalent in Knox County.  Therefore, a review of the effectiveness of your herbicides program is definitely in order.

To effectively battle these new weed problems, creating a comprehensive, all-encompassing weed control strategy is essential in today production agriculture.  Over the next 4 weeks I will share information developed by Meaghan Anderson and Dr. Bob Hartzler at Iowa State University on developing a long-term weed management system.

Last week’s post:   Herbicide program development: Using multiple sites of action

This week’s post: Herbicide program development: Using effective herbicide groups

After you’ve started working on a program that contains multiple herbicide groups (sites of action), you need to make sure you’re using multiple herbicide groups that will be effective against your target weeds. For most people, the target weed will be waterhemp. Others may have problems with giant ragweed, horseweed/marestail, or other weeds. Waterhemp is the target weed in my example, but consider what your most problematic weeds are to run through this exercise for yourself.

Things to consider when determining whether a herbicide is effective against your target weed include (1) whether the herbicide is labeled to control the weed and (2) whether your target weed is resistant to the herbicide group.

Let’s look at herbicides as if waterhemp is the weed that causes us the most issues. Here’s a table of herbicide groups used in Iowa crops.

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Developing a long-term comprehensive weed management system.

Source: Iowa State University, (Edited)

As the end of the year approaches and we reflect on the 2018 growing season we need to look at what changes or improvements we need to make in our production plans for 2019.  Herbicide resistant weeds are continuing to create problems.  New, very invasive and harmful weed species (Palmer Amaranth and Waterhemp) are now prevalent in Knox County.  Therefore, a review of the effectiveness of your herbicides program is definitely in order.

To effectively battle these new weed problems, creating a comprehensive, all-encompassing weed control strategy is essential in today production agriculture.  Over the next 4 weeks I will share information developed by Meaghan Anderson and Dr. Bob Hartzler at Iowa State University on developing a long-term weed management system.

This week’s post:   Herbicide program development: Using multiple sites of action

With the stagnant development of new herbicides and weeds seemingly evolving herbicide resistance faster than ever before, it’s important to maximize the usefulness of every herbicide application. A new herbicide site of action (or herbicide group number) for use in corn and soybean production has not been discovered since the early 1980s. According to Dr. Ian Heap with www.weedscience.org, since the 1980s, the confirmed number of unique cases of herbicide resistance globally is increasing at a rate of about 12 discoveries per year.

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Inversion and Drift Mitigation – Workshop on December 14

Inversion and Drift Mitigation Workshop
Dec. 14, 2018 • 10 a.m. – noon

10 – 11 a.m. Weather Conditions and Potential Inversions
Speaker: Aaron Wilson, Weather Specialist & Atmospheric Scientist, OSU Extension, Byrd Polar & Climate Research Center

11 – noon Using FieldWatch to Communicate
Speaker: Jared Shaffer, Plant Health Inspector, Ohio Department of Agriculture

Two choices for attending the workshop:

Attend in person (pre-registration required, limited to the first 75 people registered)
Ohio Dept. of Agriculture • Bromfield Administration Building
8995 E. Main St., Reynoldsburg, OH 43068
Click here to register

Attend virtually:
Link coming soon – no pre-registration required

No cost to attend. Core commercial and private pesticide recertification credits available only athe Reynoldsburg in-person location. Limited to the first 75 registered. No recertification credits given for virtual/internet attendees.

For more information about the workshop, contact:
Cindy Folck, folck.2@osu.edu
614-247-7898

Event sponsored by OSU Extension IPM program and the USDA NIFA Crop Protection and Pest Management Competitive Grants Program (Grant number 2017-70006-27174).