Double-Crop Soybean Weed Management

by: Dr. Mark Loux, OSU Extension

It’s been a tough summer in parts of Ohio to do anything on a timely schedule and there are some weedy fields.  The best advice we have for big weeds in full-season soybeans is to increase rates and the complexity of POST herbicide applications, while still adhering to cutoffs for the application of certain herbicides as much as possible.  Dicamba products, XtendiMax, Engenia, and Tavium, cannot legally be applied to Xtend and XtendiFlex soybeans after June 30.  This cutoff date pertains to use in double-crop soybeans also.  If you are planning on planting Xtend or XtendiFlex soybeans in double-crop fields and using dicamba as a burndown, apply before Friday.  There isn’t a cutoff date for most other POST soybean herbicides – it’s based on either crop stage (eg R1) or days before harvest.

Double crop soybeans usually need some type of weed control program, although how weedy they get depends upon weeds surviving down in the wheat that can take off once they receive light; how much rain we get in July, which drives additional weed emergence and rate of soybean growth; and how fast the soybeans grow and develop a canopy.  Control can occur via the use of pre-plant/preemergence burndown herbicides, followed by POST as needed.  It’s also possible to accomplish this with one early POST application in Enlist soybeans, using Enlist Duo or a combination of Enlist One with glyphosate or glufosinate.  And also in LLGT27 soybeans with a combination of glyphosate and glufosinate.  Herbicides need to address marestail in many fields, which is often lurking in the wheat ready to regrow.  Marestail that are taller and get cut off by the combine will be more difficult to control than the smaller intact ones below the cutter bar.  Herbicide options vary depending upon the weeds and what type of soybeans are planted.  More effective options include:

  • Glyphosate or glufosinate + Sharpen (1 oz) + MSO – any soybean, prior to emergence
  • Glyphosate or glufosinate + 2,4-D – any soybean, at least a week before planting
  • Enlist Duo; glyphosate or glufosinate + Enlist One (Enlist soybeans) – PRE or POST, no wait to plant
  • Glyphosate + XtendiMax or Engenia (Xtend or XtendiFlex soybeans) – PRE, apply by June 30
  • Glyphosate + glufosinate – PRE in any soybean, PRE or POST in LLGT27 soybean

​​​​​​​It is possible to include residual herbicides with a PRE burndown treatment, but their value in this situation is questionable.  Residual herbicides with long recrop intervals to corn should be avoided.  POST options in double-crop include glufosinate, glyphosate, Enlist One/Duo, and conventional herbicides, depending upon the type of soybean planted.  One caution here is to avoid excessive injury to soybeans that slows growth and development since this is likely to reduce yield due to the short season.  Weed emergence is reduced and variable in July compared with May and June.  Where burndown herbicides are used, but there is still a need for POST herbicides to control a flush of late-emerging weeds, consider reduced rates.  Research we conducted back in the 1990s demonstrated that weeds up to 2 inches tall can usually be controlled with half of a typical labeled rate.  When we planted soybeans in early June, the single application of a half-rate provided adequate control, versus early May when a second application was needed.  So this should be a suitable approach for double-crop soybeans.  Just be sure to start with an effective burndown at planting, and apply when weeds are well within the 2-inch size.

Ohio Department of Agriculture Reminds Pesticide Applicators of June 30 Cutoff Date for Dicamba Products

The Ohio Department of Agriculture (ODA) is reminding pesticide applicators of the June 30 cutoff date for over-the-top dicamba products to soybeans. No additional applications can be made to this year’s crop after this date, regardless of growth stage.

Dicamba is an herbicide used to help limit unwanted weeds around crops. In 2018, the Environmental Protection Agency (EPA) designated new dicamba products as restricted use, meaning they can only be used by certified applicators.

In December 2021, the EPA released its 2021 incident report, which indicated that across the United States “more than 1 million acres of non-dicamba-tolerant soybean crops were allegedly damaged by off-target movement of dicamba.” In Ohio, there were 34 reported incidents involving dicamba.

If you have questions or concerns about dicamba please contact the Division of Plant Health’s Pesticide & Fertilizer Regulation Program at (614) 728-6987 or Pesticides@agri.ohio.gov.

Rainfast Intervals, Spray Additives, and Crop Size for Postemergence Corn Herbicides

Mother nature is finally cooperating, allowing us to get some corn and beans in the ground.  Later this summer it will be time for postemergence herbicide applications.  The table below from the “2022 Weed Control Guide” lists important information on rainfast intervals, spray additives and crop size  for corn postemergence applications.

 

 

Click on each page to print a camera ready copy

 

Required Dicamba Training

I just received this from BASF and thought I would pass it along.

 

Dear Engenia® herbicide Customer,

BASF is excited to announce that annual dicamba applicator training offerings are now available. This training is required for every applicator who applies Engenia herbicide or other dicamba-based herbicides approved for over-the-top (OTT) applications on dicamba- tolerant soybean and cotton.

Applicator training and certification can be obtained in multiple formats based on your schedule and needs. Due to COVID-19, dicamba applicator training will be primarily available through online offerings such as a self-paced training module and live virtual webinars. Limited in person dicamba applicator training opportunities may be available in your area, your local BASF representative will alert you to these sessions.

Please visit www.Engeniaherbicide.com/training.html for training options.

Self-Paced Online Module:

BASF has changed platforms for the 2022 season to enhance the experience and reliability of our online training module. This self-paced option will take approximately one hour to complete and contains a mandatory quiz at the end. Once the module is completed a certificate is displayed that should be kept for your records. A copy of your certificate will also be provided to the e-mail address you use to register for the course. It is recommended that you complete this training on a web browser through a computer with a reliable internet connection.

Live Virtual Webinars:

Live webinars, hosted by BASF experts, review the same content provided in the online module but this format allows for the opportunity to address questions from attendees during the session. There will be a total of 10 events that are scheduled to occur on select Tuesdays at 10 AM Eastern. These webinars start on February 1, 2022 and run through June 7, 2022 Attendance is limited to the first 250 attendees per event so register early for the event that best fits your schedule. Live Virtual Webinars are scheduled for:

February 1, 2022 @ 10 AM Eastern

February 8, 2022 @ 10 AM Eastern

February 15, 2022 @ 10 AM Eastern

February 22, 2022 @ 10 AM Eastern

March 1, 2022 @ 10 AM Eastern

March 8, 2022 @ 10 AM Eastern

March 15, 2022 @ 10 AM Eastern

April 12, 2022 @ 10 AM Eastern

May 10, 2022 @ 10 AM Eastern

June 7, 2022 @ 10 AM Eastern

As a reminder only certified applicators may apply Engenia herbicide or other dicamba-based herbicides approved for over-the-top (OTT) applications on dicamba tolerant soybean and cotton. Some states have or are actively considering additional restrictions and requirements. Check with your state pesticide regulatory agency for additional training and application requirements or restrictions and to stay current on any new developments.

Knox County Pesticide & Fertilizer Recertification

Due to COVID uncertainties the pesticide & fertilizer recertification classes have been pushed to March. 

Thursday March 3, 5:30 – 9:30 p.m.

Wednesday March 9, 9:00 a.m. – 1:00 p.m.

Tuesday March 22, Noon – 4:00 p.m.

Fertilizer is the first session at each class

Cost = $35.00 for pesticide, $10.00 for Fertilizer, $45.00 for both

Call the Extension office at 740-397-0401 to reserve your spot.

The School will be at the new Ramser 4-H Activity Center (on the fairgrounds)

700 Perimeter Dr.  Mount Vernon, OH  43050

 

What’s the difference between Roundup and Roundup For Lawns?

Source: Kevin Frank, and Aaron Hathaway, Michigan State University Extension

These two different products are good examples of why understanding the difference between product names and herbicide active ingredients is critical.

The spring blitz of lawn care ads is in full swing as northerners emerge from their long winter slumber and begin to venture outside into the lawn. This year, a new product called Roundup For Lawns is gathering attention and has already generated questions from those wondering why they’d spray Roundup on their lawn—wouldn’t it kill the lawn?

The confusion originates from the name Roundup itself and that for most consumers, they don’t recognize Roundup is a product name such as Coke or Tylenol.

It turns out there is a lot in a name!

Roundup: The herbicide active ingredient in Roundup is glyphosate, which if sprayed on the lawn will kill not only the weeds but the lawn. This is a nonselective herbicide that controls any green plant on which it is applied.

Roundup For Lawns: The new Roundup For Lawns does not contain glyphosate. The herbicide active ingredients in Roundup For Lawns are MCPA, quinclorac, dicamba and sulfentrazone. These herbicides are effective on a broad range of weeds that might infest the lawn such as dandelion, crabgrass and nutsedge. When used properly it will not kill the desirable turfgrasses in the lawn. This is a selective herbicide that controls specific weeds, but not lawn grasses.

This is a good lesson in recognizing that product name is not the important information when selecting a herbicide—it’s the active ingredients that matter.

Reference to commercial products or trade names does not imply endorsement by Michigan State University Extension or bias against those not mentioned.

Calibration for Rate Controlled Sprayers

Source: Erdal Ozkan, OSU Extension

I had an article in last week’s CORN newsletter encouraging growers to fine tune and calibrate their sprayers. I had mentioned that the next couple of weeks may be the last best time period to do this since planting season is just about to start. There would not be any better time to do this than now. The next day I got an email from a grower asking me this question that I get often: “I have a rate controller in the cab that regulates the flow rate of the sprayer regardless of the changes in sprayer ground speed. So, should I still calibrate the sprayer to find out the application rate?”. The answer is, Yes, you should. Although the rate controllers do an excellent job with regulating the flow rate of nozzles to keep the application rate constant, a manual calibration at least once a year is needed to ensure the rate controller is functioning properly.

Here is why we should confirm the accuracy of rate controllers: Unfortunately, electronic controllers usually cannot detect flow rate changes on each nozzle on the boom, and none can detect changes in spray pattern. If a nozzle is plugged, or extremely worn out, the rate controller cannot tell us this is happening. It will still try to maintain the constant application rate by changing the system pressure and force other nozzles to spray less or more to overcome the problem in one or several nozzles. If the ground speed sensor works based on revolutions of the tractor wheels, the ground speed determined may not be accurate, because of the slippage that may occur under some ground conditions. Even the tire pressure being off just a few psi may change the tire revolutions per minute leading to erroneous travel speed readings. Finally, Controllers don’t show changes in spray patterns that may happen when a nozzle is defective, plugged, or worn-out. So, we will have to continue manually checking the flow rate of the nozzles, and visually observing the changes in spray patterns until the technology is developed to do these observations remotely, and on-the-go.

As I mentioned in the article in last week’s CORN newsletter, it usually doesn’t take more than 30 minutes to calibrate a sprayer, and only three things are needed: a watch or smart phone to record the time when measuring the nozzle flow rate or the travel speed, a measuring tape, and a jar graduated in ounces. Please take a look at the Ohio State University Extension publication FABE-520 for an easy method to calibrate a boom-type sprayer.  Here is the URL for this publication: http:// ohioline.osu.edu/factsheet/fabe-520  

Not knowing limitations of rate controllers may create serious problems. I already mentioned how smoothly the rate controllers keep the application rate the same regardless of changes in travel speed. However, this convenience comes at a cost if the controller is forced to make drastic changes in the application rate as a result of too high or too low of a travel speed. As you know, to achieve best results from pesticides, the application rate, as well as the droplet size must remain relatively unchanged during the entire spraying. When sprayer speed goes up, to maintain the pre-set application rate, the controller requires the system pressure to go up to increase the nozzle flow rate. This, unfortunately results in more drift-prone droplets coming out of the nozzle, especially if the nozzle used is designed for low application rates within the recommended pressure ranges. Conversely, when the sprayer slows down, the opposite happens: the controller forces the system to lower the pressure, in order to reduce flow rate of nozzles. This will result in production of larger than the desired size of droplets, leading to inadequate coverage. If you are spraying Dicamba or 2,4-D herbicides, you need to pay even more attention to operation of rate controllers. As you know, only a small number of nozzles at specific ranges of pressure can be used to spray these products. Significant changes in ground speed may force the rate controller to make significant changes in spray pressure that may be outside the allowable legal pressure range required to spray these herbicides. Without you realizing it, you may find yourself in violation of the label. Make sure the nozzle size selected will allow the controllers to make necessary changes in the flow rates while still staying within a safe, applicable and allowable pressure range.

Time is now to purchase the right nozzles for your spraying needs

Source: Erdal Ozkan, OSU Extension

This is the time of the year you must complete shopping for nozzles because the spraying season is just around the corner. Each part of the application equipment plays a critical role in achieving maximum performance from the sprayer. Therefore, each component must be selected carefully and must perform successfully the tasks associated with it. Although nozzles are some of the least expensive components of a sprayer, they hold a high value in their ability to influence sprayer performance. They help determine the gallon per acre intended application rate. They also influence the droplet size, which plays a significant role in achieving improved penetration into crop canopy and better coverage on the target pest, both affect the efficacy we expect from pesticides applied. Wrong choice of nozzle may hurt us in several ways, but here are the three most obvious ones: We may end up with streaks of untreated areas causing non-uniform pest control; or simply complete failure or ineffective pest control which require repeat applications; and finally, we may end up losing a significant part of the pesticides applied in the form of spray drift. Sometimes, the choice of nozzle may be determined by the requirements given on the pesticide label.

Selecting the best nozzle requires careful consideration of many important factors including: sprayer operation parameters (such as application rate, spray pressure, travel speed); type of chemical sprayed (herbicides, insecticides, fungicides); mode of action of chemicals (systemic, contact); application type (broadcast, band, directed, air assisted); target crop (field crops, vegetables, vineyard, shrubs and trees, etc.); and spray drift risk. I will briefly cover some of these topics in this article. For detailed information on nozzle selection, I strongly recommend you read a new Ohio State University Extension Publication, entitled “Selecting the Best Nozzle for the Job”. In this publication, you will see step-by-step guidelines for selecting the most appropriate spray nozzle for a given application situation. The publication is available online at following web site: http://ohioline.osu.edu/factsheet/fabe-528

Which nozzle type is best for your situation? Continue reading

New Private Pesticide Applicator Virtual Training

Source: Mark Badertscher, OSU Extension

Join OSU Extension for a virtual New Private Pesticide Applicator Training to help new pesticide applicators prepare for the Ohio Private Pesticide Applicator License scheduled for Tuesday, January 26 from 12:30-4:30 pm. The class will provide instruction in CORE, Grain, and Cereal Crops. For further study and to prepare for the test, books can be purchased from OSU Extension Publications online and shipped to your house at your expense.

Optional books for the online participants include:

Applying Pesticides Correctly (Core Manual)
https://extensionpubs.osu.edu/applying-pesticides-correctly-core-manual/

Ohio Pesticide Applicator Training: Core Student Workbook
https://extensionpubs.osu.edu/ohio-pesticide-applicator-training-core-student-workbook/

Ohio Pesticide Applicator Training: Field Crops Student Workbook
https://extensionpubs.osu.edu/ohio-pesticide-applicator-training-field-crops-student-workbook/

Register for this virtual event at https://go.osu.edu/virtualnewpesticideapplicatortraining-january26 and you will be sent a link for the class. There is no cost to participate and those who are unable to participate on the scheduled webinar date will be sent an email to watch the recording later if they register for the class. Following the class, participants can schedule an exam time at https://pested.osu.edu/PrivateApplicator/testing when they are ready to take the tests.

OHIO DEPARTMENT OF AGRICULTURE PARTNERS WITH OSU EXTENSION TO PROVIDE ONLINE PESTICIDE RECERTIFICATION OPPORTUNITIES

The temporary online trainings during the COVID-19 Pandemic allow applicators and fertilizer certificate holders to meet their continuing education requirements.

REYNOLDSBURG, Ohio (June 29, 2020) – During the COVID-19 Pandemic, the Ohio Department of Agriculture (ODA), is partnering with the Ohio State University Extension Pesticide Safety Education Program (PSEP) to temporarily provide online recertification for pesticide applicators and fertilizer certificate holders whose licenses expired in spring of 2020. The online recertification will be available Monday, July 6. For commercial applicators, it will be available August 10. For more information or to register for the online recertification, visit pested.osu.edu/onlinerecert.

The online option allows private applicators and fertilizer certificate holders due for training by March 31, 2020 and commercial applicators due for training by September 30, 2020 to meet their continuing education requirements. The cost for online training is $35 for private applicators and $10 for fertilizer certification. The price per credit hour for commercial applicators is $15. If you don’t know your license number, please call ODA at 614-728-6987, choose option 1.

Applicators are still required to meet their recertification requirements to renew licenses and certifications. As a result of HB 197, applicators have until 90 days after the emergency is over or December 1, whichever comes first, to complete their requirements. Recertification status can be checked online at https://agri.ohio.gov/wps/portal/gov/oda/divisions/plant-health/pesticides/recert-search. Applicators must also submit a completed renewal application and pay an additional fee to the ODA for licensure.

For additional information regarding online recertification, please contact the Ohio Department of Agriculture at 614-728-6987, and press 1 for licensing recertification or the OSU Pesticide Safety Education Program at 614-292-4070.

Commercial applicators must earn at least five recertification credit hours every three years, and private applicators must earn at least three recertification credit hours every three years. One hour (60 minutes) must be earned by taking one or more core education classes, one half-hour (30 minutes) of education in each category on the license, and the remaining time requirement can be met by attending classes in any category.