Roundup vs. Roundup vs. Roundup – REALLY??!

 

From a consumer standpoint this could quite possibly be the worst product marketing of ALL TIME!

 

 

Roundup has been around for a long time.  The active ingredient in “Roundup” is glyphosate.  Many of us know “Roundup” as a non-selective herbicide – i.e. it will kill all plants it contacts.

So what’s the problem?  With these products having a similar name, it’s quite possible to grab the wrong product from the shelf and thus risk harming or destroying the wrong (or all) plants.

The Solution.  Always read the label!  Products with similar names may have different active ingredients and therefore may not have the have the desired outcome.

Below is a general guide to the different Roundup products available to consumers.  Note that for many of these products there may be ready to use (RTU) and/or concentrate formulations available with different ratios or percentages of the same active ingredients.  Additional products are marketed for use in southern turfgrass.

Don’t be fooled by products that have a similar name . . . read the label!

 

Weather and herbicides – what to do (or not) this week

Source: Dr. Mark Loux, OSU

Current forecast is for fairly warm temperatures through late evening Tuesday evening, followed by a substantial drop in temperatures and chance of snow, followed by cold/cool temperatures through the weekend.  Primary question concerning this scenario seems to be whether it is okay to apply wheat or burndown herbicides prior to this cold snap.  Some things we know about herbicides and cold weather:

– Herbicides applied to an emerged crop just prior to or during cold weather may be more injurious compared with favorable weather conditions.  During cold weather when plants are not actively growing or growing slowly, the rate of translocation and metabolism of herbicide by the plant slows down, which can mean an accumulation of herbicide that is not being metabolized.  This can increase the risk of crop injury since metabolism of herbicide by the crop, or conversion to an inactive form, is what allows that herbicide to be safely used on the crop in the first place.  For some herbicides, there is such a large margin of safety with regard to crop safety that this is all inconsequential.  For others the margin is narrower and issues such as cold weather and sprayer overlaps are more important.  The inclusion of safeners in herbicide formulations reduces the risk of injury, usually be increasing the rate of metabolism, but may not completely solve issues that arise because of adverse weather or too high a dose.  So with regard to this week and risk of injury to wheat, we would recommend avoid applying herbicide once the cold weather starts (from Wednesday on), until warm weather resumes.

– There is less certainty in making a recommendation about whether to treat wheat on Tuesday prior to the cold weather.  We have seen instances in corn where application just prior to cold weather has resulted in greater injury.  Wheat is actively growing now under favorable weather, and should readily translocate and metabolize herbicides.  Much of this process occurs within the first few hours of application.  Temperatures do not really start to plunge until early Wednesday morning per the forecast.  While it’s somewhat of a guess, it seems that application during the first part of Tuesday would be possibly safer to the crop than later in the day.  Past experience has shown us that some wheat herbicides are just generally safer than others, so one option would be to omit the ones that have stricter growth stage guidelines or have more of a history of causing injury.  Having said this, in our research we have really not experienced injury from small grain herbicides applied per label.

– With regard to efficacy of burndown herbicides and cold weather, some of the same principles apply.  Applying herbicide from Wednesday through the weekend, when weeds are not actively growing, is not recommended due to the likely loss of activity.  Susceptible weeds metabolize herbicide slowly anyway, so the issue is a lack of translocation within the plant and the inability of herbicide to do it’s thing at the active site when plant processes are shut down.  This is the type of cold weather we referenced in the recent article about dandelions, when we have observed control of this weed to plummet.  We have also observed extremely slow control of overwintered annual weeds during cold weather.

– We would recommend going ahead with burndown herbicide applications on Tuesday, prior to the cold.  As with wheat, weeds are actively growing under favorable weather so we assume herbicides will work.  It’s still a bit of a guess, but it could be a while before field conditions and weather are suitable for application again.

– This is the type of scenario that makes us want to remind everyone again that a few dollars of herbicide in the fall can help avoid some of the nasty burndown issues that develop when spring conditions are less than optimum.  Just saying.

 

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.

Now is the Time to Fine Tune Your Sprayer

Source: Erdal Ozkan, OSU Extension

Pesticides need to be applied accurately and uniformly. Too little pesticide results in poor pest control and reduced yields, while too much injures the crop, wastes chemicals and money, and increases the risk of polluting the environment. Achieving satisfactory results from pesticides depends heavily on five major factors:

  1. Positive identification of the pest.
  2. Choosing the least persistent and lowest toxicity pesticide that will work.
  3. Selecting the right equipment, particularly the right type and size of nozzle for the job.
  4. Applying pesticides accurately at the right time.
  5. Calibrating and maintaining equipment to make sure the amount recommended on the chemical label is applied.

Inspection of sprayers

Higher pesticide costs and new chemicals designed to be used in lower doses make accurate application more important than ever. There is no better time than early spring to take a closer look at your sprayer. Here are some of the things I would recommend you do this week if you don’t want to unexpectantly halt your spraying later in the season when you cannot afford delaying spraying and missing that most critical time to control weeds:

  • First, if you need new or one other type of nozzles on the boom this year, do not delay purchasing new nozzles. Do it now.
  • Double-check your sprayer for mechanical problems before you start using it.  You won’t have time to do this when planting is in full swing.
  • Clean the sprayer tank thoroughly and make sure all filters on the sprayer, especially the nozzle filters are clean.
  • Clean spray nozzles to make sure they are not partially plugged. Check their flow rates, and replace the ones that are spraying more than 10 percent of the original output at a given spray pressure.
  • Check the agitator in the tank to make sure it’s working properly. This is extremely important if you will be applying dry chemicals. Run water through the spray system to make sure everything is working properly.
  • Always carry a spare, excellent quality pressure gage (glycerin filled) in your shop, and check the accuracy of the pressure gage on the sprayer compared to the reading you see on this spare pressure gage. Your rate controller will not know if your pressure gage is bad, and the flow rate of nozzles will be adjusted by the rate controller using the bad pressure gage.
  • Once you are convinced that all sprayer parts are functioning properly, it is time to calibrate the sprayer.

Calibrate the sprayer

One can determine if the chemicals are applied at the proper rate (gallons per acre) only by carefully calibrating the sprayer. Calibration, perhaps more than anything else, will have a direct impact on achieving effective pest control and the cost of crop production. While applying too little pesticide may result in ineffective pest control, too much pesticide wastes money, may damage the crop and increases the potential risk of contaminating ground water and environment. Results of “Sprayer Calibration Clinics” I participated in Ohio a while back, and data from several other States show that only one out of three to four applicators are applying chemicals at a rate that is within 5 % (plus or minus) of their intended rate (an accuracy level recommended by USDA and EPA). For example, if your intended rate is 20 gallons per acre, the 5% tolerable difference will be 1 gallon (5% of 20). So, your actual application rate should be as close to 20 gpa as possible, but not outside the range of 19 to 21 gpa.

How do you calibrate the sprayer?

There are several ways to calibrate a sprayer. Regardless of which method you choose, you will end up measuring the nozzle flow rate (in ounces), and the actual travel speed in miles per hour to determine the actual chemical applied in gallons per acre. Once you determine the actual application rate, you should find out if the difference between the actual rate and the intended rate is greater than 5% of the intended rate (plus or minus). If the error is greater than the 5% tolerable error margin, you will need to reduce the error below 5% by doing one of three things: 1) Change the spraying pressure, 2) change the travel speed, and 3) change nozzles (get a different size) if the error cannot be reduced below 5% by making adjustments in either the pressure or the travel speed, or both.

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 for calibrating a field crop (with boom) sprayer.  Here is the URL for this publication: http://ohioline.osu.edu/factsheet/fabe-520 

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

Herbicide Resistance in Ohio Waterhemp Populations

Source:  Mark Loux, OSU Extension

Waterhemp populations across the Midwest continue to develop more complex variations of herbicide resistance.  Multiple resistance to an increasing number of herbicide sites of action is the norm in many populations in states west of Ohio.  Waterhemp has on the whole developed resistance to seven sites of action, including the following:

Group 2 – ALS inhibitors – chlorimuron, imazethapyr, etc

Group 4 – Synthetic auxins – 2,4-D, dicamba, etc

Group 5 – Photosystem II inhibitors – atrazine, metribuzin, etc

Group 9 – EPSP synthase inhibitor – glyphosate

Group 14 – PPO inhibitors – fomesafen, flumioxazin, sulfentrazone, etc

Group 15 – long chain fatty acid inhibitors – metolachlor, pyroxasulfone, etc

Group 27 – HPPD inhibitors – mesotrione, isoxaflutole, topramezone, etc

Individual populations with resistance to three or more sites of action are common.  Mutations are occurring that confer resistance to several of these sites of action simultaneously, through a resistance mechanism that enhances the metabolism and inactivation of the herbicides by the plant.  For example, there appears to be a linkage in the resistance to mesotrione and atrazine, where resistance to one means it’s likely that resistance to the other occurs also.  Weed scientists have concluded that this weed is capable of developing resistance to any herbicide site of action used against it.  We aren’t actually sure what the correct recommendation is for stewardship of herbicides once a single mutation can confer resistance to multiple sites of action.  Which is the reason we stress the need to take steps in mid to late season to prevent seed from plants that survive management strategies.

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.

Reminder! Register for Precision University Today

Source:  John Barker, Amanda Douridas, Ken Ford, John Fulton, Mary Griffith, Will Hamman, Elizabeth Hawkins

Tackling Spring Operations with Reduced Working Days

January 5, the first virtual Precision University event, is quickly approaching. Be sure to register today so you do not miss out on important information to help you improve spring performance. The 2021 focus is “Tackling Spring Operations with Reduced Working Days.” Speakers from around the country will share their research and experience centered on the challenges farmers face during spring with changing weather patterns.

January 5 – Gambling with Planting Decisions – Dr. Aaron Wilson (Ohio State University Extension) and Dr. Bob Nielsen (Purdue University). 1 CCA CM Credit.

January 12 – Improving Fertilizer Efficiency with the Planter Pass – Matt Bennett (Precision Planting Technology) and Dr. John Fulton (Ohio State University). 1 CCA PAg Credit

January 19 – Pre-season Crop Protection Decisions – Dr. Mark Loux and Dr. Scott Shearer (Ohio State University). 0.5 CCA PM and 0.5 PAg Credits.

January 26 – Sprayer Technology to Improve Field Performance – Dr. Joe Luck (University of Nebraska-Lincoln). 1 CCA PAg Credit.

There is no cost to attend Precision University, but registration is required. For more information or to register, visit http://go.osu.edu/PrecisionU. If you have any questions about the Precision U sessions, please feel free to contact Amanda Douridas (Douridas.9@osu.edu).

 

Dicamba Approved for Over-the-Top Use 2021 and Beyond

Source: Agweb.com

Tuesday, Oct. 27, 2020, the Environmental Protection Agency (EPA) announced it will approve three of the new dicamba formulations for over-the-top use for five years, according to EPA Administrator Andrew Wheeler. The herbicide is labeled for use in soybeans and cotton with the trait that confers tolerance to dicamba.

The specific formulations include Xtendimax VaporGrip Xtra, Engenia and Tavium. The registration starts next year (2021) and runs through 2025. The administrator said they opted for a five-year registration, which is typical for pesticides, instead of a two-year like dicamba has experienced in the past because they had more data to base this decision upon.

“EPA will register dicamba for over-the-top use on dicamba tolerant cotton and soybeans, this decision provides a five-year registration to provide certainty to growers,” Wheeler says. “EPA. has determined that these registrations address the concerns outlined in the June 9th Circuit Court of Appeals decision.”

The administration said it reviewed 65 new studies when making this decision, reviewed all literature and consulted with experts before making this decision.

In approving the herbicide for use in cotton and soybeans, EPA provided the following changes to the herbicide labels. These changes, and all label instructions, must be followed for legal use:

  • Downwind buffer of 240′ is required and a buffer of 310′ required where listed species are located.
  • Over-the-top application of dicamba of soybeans prohibited nationwide after June 30, and after July 30 in cotton.
  • An approved pH buffering agent will be required to be mixed for application to lower volatility. Buffering agents are registered with the EPA and must be documented each use.
  • Opportunities for growers to use hooded sprayers to reduce buffers.
  • States can expand over-the-top use to meet local needs by working with EPA.

“All of these efforts will help ensure there are not negative impacts on other farmers’ lands,” Wheeler continued. “States can further restrict, but they have to work with us and file the appropriate requests with EPA. We’re trying to have a national program here, we’re responding the the court’s concerns with a national cutoff.”

Dicamba’s use was hotly contested earlier this year. An appeals court vacated the product’s use in early June, which was followed by an exemption for use of stocks on-hand for farmers by EPA. The announcement brough confusion and brought dicamba’s compliance with the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) under the microscope. EPA took those concerns into consideration while making this decision.

“The economic damage that would result from not being able to use dicamba herbicides would be tremendous,” said Ken Fountain, National Cotton Council chairman. “We greatly appreciate EPA’s timely issuance of a new five-year label for the critical crop protection product for cotton farmers.”

Some have already expressed concerns about EPA’s most recent announcement.

“Rather than evaluating the significant costs of dicamba drift as the 9th Circuit told them the law required, EPA rushed re-approval as a political prop just before the election, sentencing farmers and the environment to another five years of unacceptable damage,” said George Kimbrell, legal director at the Center for Food Safety. “Center for Food Safety will most certainly challenge these unlawful approvals.”

This story will be updated with quotes and information as it becomes available.