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 

Poison Hemlock Control

Source: Mark Loux, Curtis Young, OSU Extension

Poison hemlock remains one of the more persistent and prevalent poisonous weeds that we deal with in Ohio.  It’s most typically a biennial plant (sometimes perennial), emerging from seed in year one and developing into a low-growing rosette by late fall.  The rosette overwinters and then resumes growth in the spring of year two.  Stem elongation initiates sooner in spring than many other biennials, and this is followed by continued growth and development into the often very tall plant with substantial overall size.  Flowering and seed production occur in summer.

Failure to control poison hemlock occurs partly because, while it often grows in edges and fencerows around crop fields, no one really pays much attention to it until it does reach this large size when it’s less susceptible to herbicides.  And everyone is busy getting crops planted  in spring anyway so control of hemlock gets low priority.  Stages in the poison hemlock life cycle when it is most susceptible to control with herbicides are:  1) fall, when in the low-growing rosette stage; and 2) early spring before stem elongation occurs.  It’s most easily controlled in fall, but several products can work well in spring.  Herbicide effectiveness ratings for poison hemlock can be found in Table 21 of the current Weed Control Guide for Ohio, Indiana, and Illinois.  Herbicides rated 8 or 9 on poison hemlock include the following:  9 – Crossbow, Remedy Ultra; 8 – Cimarron Max, Curtail, dicamba, glyphosate.  Mixing glyphosate and dicamba can improve control compared with either applied alone.

Several online resources cover poison hemlock more comprehensively than this article does, including this one from the University of Missouri.  Information on toxicity can also be found via an internet search or by contacting OSU Extension if help is needed to resolve a specific concern.

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.

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Corn College and Soybean School

The Agronomic Crops Team will host a virtual Corn College and Soybean School on February 11, 2021. Corn College is in the morning, from 9:00 – 12:00pm, with Soybean School in the afternoon from 1:00-4:00pm. Each program will feature updates from OSU Specialists. CCA CEUs are available. The schedule for the day is as follows:

 

Corn College, 9:00am-12:00pm

  • Corn Management for 2021, Peter Thomison, 1.0 CM CCA CEUs
  • Meeting Nutrient Needs in Corn, Steve Culman, 1.0 NM CCA CEUs
  • Disease Management, Pierce Paul, 1.0 PM CCA CEUs
  • Insect Management, Andy Michel, 1.0 PM CCA CEUs

Soybean School, 1:00-4:00pm

  • Soybean Management for 2021, Laura Lindsey, 1.0 CM CCA CEUs
  • Weed Management, Mark Loux, 1.0 PM CCA CEUs
  • Disease Management, Anne Dorrance, 1.0 PM CCA CEUs
  • Insect Management, Kelley Tilmon, 1.0 PM CCA CEUs

This program is free to attend. Register at www.go.osu.edu/agronomyschools.

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).

 

Noxious weeds on your property: what is your responsibility?

Source: Ellen Essman, OSU

Despite the fact that “pumpkin spice” everything is back in stores, it is still summer, and if you’re anything like me, you’re still dealing with weeds. In fact, we have been receiving many questions about noxious weeds lately.  This blog post is meant to be a refresher about what you should do if noxious weeds sprout up on your property.

What are noxious weeds?

The Ohio Department of Agriculture (ODA) is in charge of designating “prohibited noxious weeds.”  The list may change from time to time, but currently, noxious weeds include:

  • Shatter cane (Sorghum bicolor)
  •  Russian thistle (Salsola Kali var. tenuifolia).
  • Johnsongrass (Sorghum halepense ).
  •  Wild parsnip (Pastinaca sativa).
  • Grapevines (Vitis spp.), when growing in groups of one hundred or more and not pruned, sprayed, cultivated, or otherwise maintained for two consecutive years.
  • Canada thistle (Cirsium arvense ).
  • Poison hemlock (Conium maculatum).
  •  Cressleaf groundsel (Senecio glabellus).
  • Musk thistle (Carduus nutans).
  • Purple loosestrife (Lythrum salicaria).
  • Mile-A-Minute Weed (Polygonum perfoliatum).
  • Giant Hogweed (Heracleum mantegazzianum).
  • Apple of Peru (Nicandra physalodes).
  • Marestail (Conyza canadensis)
  • Kochia (Bassia scoparia).
  • Palmer amaranth (Amaranthus palmeri).
  • Kudzu (Pueraria montana var. lobata).
  • Japanese knotweed (Polygonum cuspidatum).
  • Yellow Groove Bamboo (Phyllostachys aureasculata), when the plant has spread from its original premise of planting and is not being maintained.
  • Field bindweed (Convolvulus arvensis).
  • Heart-podded hoary cress (Lepidium draba sub. draba).
  • Hairy whitetop or ballcress Lepidium appelianum).
  • Perennial sowthistle (Sonchus arvensis).
  • Russian knapweed (Acroptilon repens).
  • Leafy spurge (Euphorbia esula).
  • Hedge bindweed (Calystegia sepium).
  • Serrated tussock (Nassella trichotoma).
  • Columbus grass (Sorghum x almum).
  • Musk thistle (Carduus nutans).
  • Forage Kochia (Bassia prostrata).
  • Water Hemp (Amaranthus tuberculatus).

The list of noxious weeds can be found in the Ohio Administrative Code section 901:5-37-01. In addition to this list, Ohio State has a guidebook that will help you identify noxious weeds in Ohio, which is available here.  It may be helpful to familiarize yourself with the weeds in the book, so you can be on the lookout for noxious weeds on your property.

When am I responsible for noxious weeds?

The Ohio Revised Code addresses noxious weeds in different parts of the code. When it comes to noxious weeds on the property of private individuals, there are two scenarios that may apply: noxious weeds on private property, and noxious weeds in line fence rows.

Noxious weeds on your property

If your property is located outside of a municipality, a neighbor or another member of the public can inform the township trustees in writing that there are noxious weeds on your property. If this happens, the township trustees must then turn around and notify you about the existence of noxious weeds. After receiving a letter from the trustees, you must either destroy the weeds or show the township trustees why there is no need for doing so. If you do not take one of these actions within five days of the trustees’ notice, the township trustees must cause the weeds to be cut or destroyed, and the county auditor will assess the costs for destroying the weeds against your real property taxes.  If your land is in a municipality, similar laws apply, but you would be dealing with the legislative authority, like the city council, instead of township trustees.

What if you rent out your land out to be farmed or otherwise?  Are you responsible for noxious weeds on your property in that situation?  The answer is probably.  The law states that the board of township trustees “shall notify the owner, lessee, agent, or tenant having charge of the land” that they have received information about noxious weeds on the property (emphasis added).  Furthermore, the law says that the “person notified” shall cut or destroy the weeds (or have them cut or destroyed).  In all likelihood, if you own the land, you are going to be the person who is notified by the trustees about the presence of weeds.  If you rent out your property to be farmed or otherwise, you may want to include who is responsible for noxious weeds in the language of the lease.

Noxious weeds in the fence row

The “line fence law” or “partition fence law” in Ohio requires landowners in unincorporated areas to cut all noxious weeds, brush, briers and thistles within four feet and in the corners of a line fence. A line fence (or partition fence) is a fence that is on the boundary line between two properties. If you fail to keep your side of the fence row clear of noxious weeds and other vegetation, Ohio law provides a route for adjacent landowners concerned about the weeds. First, an adjacent landowner must request that you clear the fence row of weeds and must allow you ten days to do so. If the weeds still remain after ten days, the complaining landowner may notify the township trustees of the situation. Then, the township trustees must view the property and determine whether there is sufficient reason to remove weeds and vegetation from the fence row. If they determine that the weeds should be removed, the township trustees may hire someone to clear the fence row.  Once again, if this occurs, the county auditor will assess the costs of destruction on your property taxes.

Being aware of noxious weeds is key. 

As a landowner, it is really important for you to keep an eye out for noxious weeds on your property.  If you keep on top of the weeds, cutting them or otherwise destroying them as they grow, it will certainly make your life a lot easier. You will avoid awkward conversations with neighbors, letters from your township trustees, and extra charges on your property taxes. Additionally, you will help to prevent the harm that noxious weeds may cause to crops, livestock, and ecosystems in general.

To learn more about Ohio’s noxious weed laws, you can access our law bulletin on the subject here.  While the bulletin addresses the responsibilities of landowners, it also goes beyond the scope of this blog post, addressing weeds on roadways, railroads, and public lands, as well as how to respond if your neighbor has noxious weeds on their property.  Additionally, the bulletin has a helpful section of “frequently asked questions” regarding noxious weeds.

Burndown Herbicides for No-till Wheat

Source:  Mark Loux, OSU

Herbicide options for burndown of existing weeds prior to planting of no-till wheat include glyphosate, Gramoxone, Sharpen, and dicamba.  Among these, the combination of glyphosate and Sharpen probably provides the best combination of efficacy on marestail, flexibility in application timing and residual control.  Dicamba labels have the following restriction on preplant applications – “allow 10 days between application and planting for each 0.25 lb ai/A used”.  A rate of 0.5 lb ai/A would therefore need to be applied at least 20 days before planting.  We do not know of any 2,4-D product labels that support the use of 2,4-D prior to or at the time wheat planting.  There is some risk of stand reduction and injury to wheat from applications of 2,4-D too close to the time of planting.  Liberty and other glufosinate products are also not labeled for use as a burndown treatment for wheat.  Sharpen should provide limited residual control of winter annuals that emerge after herbicide application, and the rate can be increased from 1 to 2 oz/A to improve the length of residual.  Gramoxone should also effectively control small seedlings of marestail and other winter annuals.  Be sure to use the appropriate adjuvants with any of these, and increase spray volume to 15 to 20 gpa to ensure adequate coverage with Sharpen or Gramoxone.

There are several effective postemergence herbicide treatments for wheat that can be applied in November to control these weeds, in fields where preplant burndown treatments are not used.  The most effective postemergence treatments include Huskie, Quelex, or mixtures of dicamba with either Peak, tribenuron (Express etc), or a tribenuron/thifensulfuron premix (Harmony Xtra etc).  We discourage application of 2,4-D to emerged wheat in the fall due to the risk of injury and yield reduction.

Herbicide Residue Considerations for Fall Cover Crop Establishment

Source: Alyssa Essman, Mark Loux, OSU

Herbicides with residual that are used in corn and soybeans can affect the establishment of fall-planted cover crops, and should be taken into account when planning cover crop practices and selecting species. Soil characteristics and weather also play a role in the persistence of residual herbicides, which can vary by field and year. More information is needed on rotational intervals for many cover crop species, and this information is often not included on herbicide labels. University weed scientists have studied the effect of residual herbicides on some of the most popular cover crop species in order to provide this information to growers. In general, residual herbicides that control grass weeds can hinder establishment of grass cover crop species. Broadleaf cover crop species are most impacted by group 2 (ALS inhibitors), 5 (PSII inhibitors), 14 (PPO inhibitors), and 27 (HPPD inhibitors) herbicides (Purdue University).

A multi-state study found that the general order of sensitivity of cover crops to herbicide carryover, from greatest to least sensitive, is:

  • Tillage radish > Austrian winter pea > crimson clover = annual ryegrass > winter wheat = winter oats > hairy vetch = cereal rye.

Soybean herbicides that tended to be most injurious were:

  • Fomesafen, pyroxasulfone, imazethapyr, acetochlor, and sulfentrazone.

Corn herbicide treatments that were most injurious to cover crops were:

  • Topramezone, mesotrione, clopyralid, isoxaflutole, pyroxasulfone, and nicosulfuron

(University of Missouri).

Below is a table of commonly used corn and soybean herbicides, the fall cover crops that are safe to plant in rotation, and cover crop species that may be injured following these herbicides (Adapted from Lingenfelter D. and Curran W., Penn State University).

 

 

Cover crops provide a multitude of benefits and their use is becoming an increasingly popular practice in Ohio. Including cover crops in rotation with agronomic crops to realize these benefits costs time and money. It is important to evaluate the potential risk of herbicide residue on the establishment of cover crops in order to ensure success. Residual herbicides applied at the time of planting typically interfere with cover crop establishment less than those applied POST. Weather can affect the persistence of herbicides also, especially rainfall in summer.  The risk of residual herbicides affecting cover establishment will be higher in areas that have been dry since herbicide application.  Risk will be lower where the herbicide application was followed by some wet weather to get herbicide degradation started, compared with an application during prolonged dry weather.  One of the least problematic cover crop species is cereal rye, which can be successfully established following a late corn or soybean harvest, and is tolerant to a most of the most commonly used corn and soybean herbicides. Weed control should continue to be the priority in selecting herbicides, and cover crop species selection should be based on potential injury and goals for the use of cover crops.  The introductory section of the “Weed Control Guide for Ohio, Indiana, and Illinois” has some of the same information presented here, and OSU weed scientists also summarize this in a video: https://www.youtube.com/watch?v=ylr0zGnXMfs

The following resources contain information on residual herbicides and cove crops also:

https://extension.psu.edu/corn-herbicides-and-rotation-to-cover-crops https://extension.psu.edu/soybean-herbicides-and-rotation-to-cover-crops

https://ipm.missouri.edu/IPCM/2020/3/coverCropTermination-KB/

https://ag.purdue.edu/btny/weedscience/Documents/covercropcarryover.pdf