With the aggressive spread of herbicide-resistant weeds across the United States, weed scientists recommend an integrated approach to weed management. A weed control strategy for winter and spring wheat begins with a proactive plan that uses multiple best management practices (BMPs) to effectively control tough-to-manage and resistant weeds.
Take every measure possible to keep fields weed-free. When weeds are allowed to go to seed and enter the soil seed bank, they can cause problems years down the road. For cereals growers, be especially aware of weed and grass species such as kochia, Russian thistle, prickly lettuce, downy brome, barnyard grass, wild oats and foxtail.
Growers should start and finish with a clean field. Upon germination, weeds compete with your crop and rob sunlight, soil, water and nutrients that are critical for good stand establishment. According to the University of Nebraska-Lincoln Extension, it’s estimated that broadleaf weeds account for a 10 percent yield reduction in winter wheat annually. When wheat is priced at $6 per bushel, that’s a $35 million loss per year for Nebraska wheat growers.
In addition, when a grower runs a planter through a weedy field, the weeds often become damaged and more difficult to manage if subsequent herbicide applications are needed. Without effective control, weeds can lead to slow harvest and price dockage at the elevator because of weed seeds and increased grain moisture.
When choosing herbicides to control problem weeds in fields, take resistance management into consideration. For over two decades, common weeds in wheat have been resistant to ALS herbicides frequently used in wheat. Weed resistance to other chemistries such as glyphosate, PPO, ACCase and HPPD continues to spread, along with other problem weeds such as pigweeds, winter annual mustards, kochia and marestail in wheat and other crops.
To control tough-to-manage and resistant weeds, growers should tank-mix herbicides with multiple sites of action in the tank to prevent selection for resistant weed biotypes. Growers have been able to control most resistant weeds by adding different sites of action with ALS and protect the value of the chemistry. Use the same practices to protect newer chemistries as well. Rotating sites of action should be a standard practice for all farmers.
When choosing a pre-emergence herbicide, consider the following:
- Labeled length of residual activity
- Application timing
- Weed control spectrum
- Resistance management
- Crop rotation flexibility
Dr. Richard Zollinger, North Dakota State University Extension weed specialist, describes additional weed management considerations and how much impact weeds can have on wheat yields when left uncontrolled. He provides the following statistics:
- Wheat yields can be reduced by 10 to 20 bushels per acre or 35 percent when 10 wild mustard or wild oat plants per square foot infest a wheat field.
- Wheat yields can be reduced by 30 percent with two to three kochia plants per square foot.
- Yields may be reduced by 60 percent when Canada thistle patches infest a field.
- If late planting occurs, wheat yields can be reduced 10 to 15 percent by green foxtail infestations.
Experts agree a system approach to weed control should include fall or early spring applications, burndown, tank mixes and the treatment of weeds when they are small. In today’s environment, there’s no such thing as an economic threshold for weeds. Zero tolerance for resistant seed in the soil bank should be the goal.
Bayer offers a broad portfolio of herbicides to control tough-to-manage and resistant weeds in cereals. A well-thought-out herbicide program, using multiple sites of action and nonchemical practices, should be implemented.
Growers can use RT3® herbicide (9) plus Olympus® 70% Water Dispersible Granular Herbicide (2) at burndown as a cost-effective, reliable solution to control a broad-spectrum of weeds in spring and winter wheat. With excellent crop tolerance, Olympus allows for pre-plant, pre-emergence and postemergence application in spring wheat crops.
For postemergence weed control, growers can use Huskie® herbicide, Huskie® Complete herbicide or Luxxur™ herbicide.
Powered by multiple sites of action, Huskie herbicide (6,27) effectively controls a wide spectrum of broadleaf weeds, including resistant types.
Huskie Complete herbicide (2, 27, 6) is an all-in-one wheat herbicide and is a combination of Huskie with ALS grass control and an HPPD-inhibitor chemistry. Together, these sites of action provide good control of green and yellow foxtail along with 50 grass and broadleaf weeds.
Designed for excellent weed control, Luxxur herbicide (2) from Bayer helps protect your wheat fields from many yield-robbing grass and broadleaf weeds including Canada thistle, green and yellow foxtail, narrow-leaved hawksbeard and wild oats. By managing these problematic weeds, Luxxur herbicide works to help keep wheat fields clean. With excellent rotational flexibility, Luxxur allows you to rotate back to sensitive pulse crops, such as peas, lentils and chickpeas, in the following growing season.
To learn more about using herbicides with effective sites of action, see the Herbicide Resistance Management Guide. View Bayer’s product portfolio to learn more about weed control from Bayer or contact your local Bayer representative.
ALWAYS READ AND FOLLOW PESTICIDE LABEL DIRECTIONS. Roundup Technology® includes glyphosate-based herbicide technologies.
Huskie® Complete is a restricted use pesticide. Not all products are registered in all states and may be subject to use restrictions. The distribution, sale, or use of an unregistered pesticide is a violation of federal and/or state law and is strictly prohibited. Check with your local dealer or representative for the product registration status in your state. Tank mixtures: The applicable labeling for each product must be in the possession of the user at the time of application. Follow applicable use instructions, including application rates, precautions and restrictions of each product used in the tank mixture. Not all tank mix product formulations have been tested for compatibility or performance other than specifically listed by brand name. Always predetermine the compatibility of tank mixtures by mixing small proportional quantities in advance. Bayer, Bayer Cross, Huskie®, Luxxur™, Olympus®, Roundup Technology® and RT 3® are trademarks of Bayer Group. For additional product information call toll-free 1-866-99-BAYER (1-866-992-2937) or visit our website at www.BayerCropScience.us. Bayer CropScience LP, 800 North Lindbergh Boulevard, St. Louis, MO 63167. ©2020 Bayer Group. All rights reserved.
Wild oats infest a wheat crop. This and other prolific weed species known to infest cereals should be approached proactively.