Weed Research Results

Weeds are a real challenge for farmers, competing with plants for nutrients and moisture.

In fiscal year 2012-13, the Michigan Wheat Program began funding research on weed control that included a strategy for controlling windgrass, as well as the impact of herbicides.

To date, all wheat weed research has been performed by Dr. Christy Sprague, professor in the Department of Plant, Soil & Microbial Sciences at Michigan State University. She has spoken at numerous Michigan Wheat Program field days and winter meetings.

Sprague is an expert on integrated weed management, including the biology, ecology and management of weeds.

Wheat farmers will be interested in the following reports developed by Sprague and funded by the Michigan Wheat Program.

Some of the projects are complete or final; others are still on-going. The links below are to the most recent reports.

Research on Herbicide Use with Wheat

2023 Report:  Weed Control and Crop Tolerance from Fall Herbicide Applications – Year 1

Research by Dr. Christy Sprague

The goal of this project is to learn whether fall control of weeds can improve wheat establishment and vigor, thereby lessening the need for spring herbicide applications.

Dr. Sprague began by taking the wide fall planting window (6 to 8 weeks) for winter wheat into account. She planted one set of plots September 23 and the other a month later with Wharf soft red wheat seed. Each planting was divided into eight different herbicide test plots plus a control in a single farm location.

Overall, Sprague noted, in this first year of the project herbicide selection did not affect wheat yield when applied in fall. Planting date had more of an effect on yield, she noted.  This research will be repeated in 2023-2024 in two locations.

Click below to review Dr. Sprague’s 2023 final report.

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2022 Report:  Strategies to Manage Horseweed in Winter Wheat – Year 2

Research by Dr. Christy Sprague

This is the final report for the two-year project; much of the background is found in the 2021 Report (below). Trials took place at the MSU Mason and Agronomy Farms where horseweed has become established.

The 2022 project focused not only on horseweed/marestail control, but also the best management strategies for this “new” weed post-harvest. Harvesting wheat removes the crop canopy which allows horseweed to flourish and “go to seed” if not managed promptly.

Glyphosate would normally be the herbicide of choice, but widespread glyphosate resistance has growers seeking other solutions, Sprague noted. For this project, two varieties of soft red winter wheat were drilled in late October; compared to the 2021 project, Sprague added fall herbicide applications in the 2022 crop trials.

Post-harvest, the Sprague team applied 15 different herbicide treatments in-field to 1-inch-tall horseweed; charts and graphs in the report linked below show both the treatments and results.  In addition, Sprague looked at control of common chickweed and ragweed post-harvest.

Click below to review the 2022 final written report on this project. Results will be incorporated in the Michigan Weed Control Guide for Field Crops (E0434).

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2021 Report:  Strategies to Manage Horseweed in Winter Wheat – Year 1

Research by Dr. Christy Sprague

This research project recognizes that horseweed (marestail) is becoming a bigger problem for winter wheat, moving from low-growing, no-till crops into tilled fields such as winter wheat.  This impacts both quality and yield of wheat.

Moreover, the wheat-corn-soybean rotation enables the horsetail to become better established if certain post-harvest practices are not followed. Each horsetail plant – if allowed to mature – produces 200,000 seeds. Reports indicate that 125 horseweed plants grew 400 ft. from the original source weed!  Also, the practice of allowing marestail to remain in the field after wheat harvest rather than performing a fall burndown contributes to quick population growth.

In the first year of this two-year project, Sprague looked for negative impacts on the winter wheat crop of five different fall herbicide treatments for horseweed; which herbicides were most effective against horseweed; and the effect of horseweed competition on winter wheat yield.

Click below to review the 2021 PowerPoint slides and the final written report on this project.

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Three-year project on Roughstalk Bluegrass (RSBG) Control  (2018-20)

Research by Dr. Christy Sprague

Following the third year of research into better managing RSBG, Sprague has developed recommended control measures including optimal timing and herbicides to control this emerging wheat pest. If not controlled, Sprague has noted yield reductions of 33-54% making control of RSBG very important.

More specifically, Sprague has observed that RSBG control is best when done when the weed is <3” tall before it heads out. Her reports also include herbicide combinations that may be tank-mixed. These recommendations have been incorporated into the 2020 MSU Weed Control Guide for Field Crops.

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Continued support for Weed Research in Wheat  (2016-17)

Research by Dr. Christy Sprague

In an addendum to the 2014-15 project covered below, Dr. Christy Sprague addressed two new areas of concern to Michigan wheat farmers:  How do new herbicides compare with current herbicides for use with wheat; and what are the options for roughstalk bluegrass (RSBG) control.

Regarding new herbicides, the study compared Talinor and Quelex with the herbicides listed in the 2014-15 project.  The second project looked at Osprey, PwerFlex HL, Axial XL and Olympus as treatments for RSBG control.

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Impact of Weed Management Timing on Frost-seeded Red Clover Survival, Weed Control and Winter Wheat Yield (2014-15)

Research by Dr. Christy Sprague

In the second of two years, this project reviewed how fall and spring herbicide applications impact a clover cover crop, the wheat itself and wheat yield. The 2014 project studied the survival rate of the clover, weed control and wheat tolerance for the herbicide treatment. Herbicides studied included Affinity BroadSpec, Huskie, Osprey, PowerFlex, Clarity and 2,4-D.

The 2015 project followed the same treatments as 2014 with the addition of MCPA in fall or spring; and fall Affinity BroadSpec or Huskie followed by spring MCPA. (2014-15 project)

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Preharvest Herbicide Application Effects on Wheat Harvestability (2014-15)

Research by Dr. Christy Sprague

This project studied which preharvest herbicide treatments were most helpful in reducing weed residue and reducing dockages at the elevator. Treatments included Clarity; 2,4-D; Aim; Sharpen; Roundup PowerMax; Roundup PowerMax + Sharpen; and Roundup PowerMax + Aim. Weeds in the trial were lambsquarters and ragweed. (2014-15 project)

Research on Weed Control

Management of a New Grass Weed Problem:  Roughstalk Bluegrass in Winter Wheat   (2017-18)

Research by Dr. Christy Sprague

A common turfgrass weed, roughstalk bluegrass, has recently moved into some Michigan wheat fields with very negative effects. Roughstalk bluegrass can reduce wheat yields up to 50 percent if not controlled.  In this project Sprague sprayed and analyzed various rates of four common herbicides to identify best timing and control measures.

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Investigating Common Windgrass Management Systems in Winter Wheat (2012)

Research by Dr. Christy Sprague

In this project Sprague sprayed, maintained and analyzed results of several different herbicides on wheat plots infested with windgrass. The study included pre-emergent and post-emergent summer-fall treatments, along with spring treatments.