Expert: Be Cautious With Late-Season Soybean Herbicides

While a hoe may not be the preferred tool for late-season weed control, University of Illinois Extension weed specialist Aaron Hager cautions producers about spraying herbicides.

“Herbicides applied at this time of year typically target large weeds, with results often less than desired with respect to the level of weed control achieved and increased potential for other problems,” Hager said.

One of the most common scenarios is the application of diphenylether herbicides such as Flexstar, Cobra and Ultra Blazer for waterhemp plants not controlled by a previous herbicide application. In non-GMO and glyphosate-resistant soybean varieties, Hager said these herbicide active ingredients can provide good to excellent control of small waterhemp, but control is often poor when waterhemp plants exceed 5 to 6 inches.

“These herbicides do not translocate following absorption into the plant and the contact leaf burn they cause can vary according to product, spray additive and environmental conditions,” he said. “Soybean injury following application of these herbicides can be severe and should be avoided at this point of the growing season.”

The only way to control large waterhemp plants at this time is through physical removal, he said. Nearly all herbicide labels have rotational crop intervals that specify the amount of time that must elapse between herbicide application and planting a rotational crop. This becomes particularly important with late-season herbicide applications.

“These intervals are established to reduce the likelihood that herbicide residues will persist in sufficient quantities to adversely affect the rotational crop,” Hager said. “Some herbicide rotational restrictions are based solely on time, while other factors, such as soil pH and the amount of precipitation received after herbicide application, can influence the length of the crop rotational intervals.”

Hager said soil moisture is often the most critical factor governing the efficacy and persistence of soil-residual herbicides. Many herbicides are degraded in soil by the activity of soil microorganisms, and populations of these microorganisms can be greatly depressed when soil moisture is limited.

For more information on late-season herbicide applications, click here.

(Source: Illinois Ag Connection)

Leave a Reply

Herbicides Stories
HerbicidesScouting Key To Next Season’s Soybean Herbicide Program
August 12, 2014
When growing soybeans, growers need to think ahead to stay one step ahead of weeds. That means examining weed threats and evaluating which herbicides work best. Read More
Winter Wheat
HerbicidesArysta Touts Burndown Herbicide For Brome Management In Wheat
June 4, 2014
Arysta LifeScience North America recommends PRE-PARE Burndown Herbicide for effective brome management in winter wheat. Read More
HerbicidesFall Herbicide Applications More Effectively Manage Resistant Italian Ryegrass
May 14, 2014
Field studies show that a fall application of certain herbicides before weed emergence, leads to more successful crop planting and weed control in spring. Read More
Waterhemp in soybean stubble
HerbicidesThe Weed Resistance Problem: A Matter Of Billions
April 1, 2014
Not only is the amount of money being spent to control these yield robbers high, but the toll it has taken on the human population is growing lager by the day. Read More
Top 100 Articles
CropLife 100Pinnacle Agriculture Acquires Minnesota Retailer
April 14, 2015
Pinnacle Agriculture Holdings, LLC, ranked No. 6 on the CropLife 100,  has successfully acquired Liebl Ag, LLC in Ada, MN.  Read More
CropLife 100CHS, Aurora Cooperative Complete Fertilizer Storage, Grain Shuttle Loading Facility
April 13, 2015
CHS Inc., the nation’s leading cooperative and ranked No. 5 on the CropLife 100, and Aurora Cooperative (ranked No. 21) Read More
CropLife 100GROWMARK Acquires Missouri Refined Fuels Terminal
April 2, 2015
Bloomington, IL-based GROWMARK and Magellan Pipeline Co. have entered into an agreement in which GROWMARK will acquire the refined fuels Read More
CropLife 100Wilbur-Ellis Acquires South Dakota Retailer
April 2, 2015
Wilbur-Ellis Co.’s Agribusiness Division, a recognized leader in precision agriculture technology and the distribution and marketing of plant protection, seed Read More
CropLife 100The McGregor Co. Closes Smith-Kem Acquisition
April 2, 2015
The McGregor Co. — ranked No. 16 on the CropLife 100 list of largest U.S. ag retailers — has completed Read More
CropLife 100BRANDT Commemorates National Ag Day
March 20, 2015
The Illinois agriculture community gathered at BRANDT global headquarters on March 18 to celebrate National Ag Day behind this year's theme Sustaining Future Generations. Read More
Latest News
Cornfield near Sioux City Iowa
HerbicidesU.S. Regulators May Start Testing Food For Glyphosate R…
April 21, 2015
U.S. regulators may start testing food products for residues of the world’s most widely used herbicide, EPA told Reuters’ Carey Read More
FungicidesBRANDT Adds Zonix Biofungicide To Portfolio
April 21, 2015
BRANDT has added Zonix biofungicide to its rapidly expanding line of organic and sustainable products. Zonix is a contact fungicide that Read More
ManagementMissouri Experts: Spring Planting Slow Start Won’…
April 20, 2015
In the first of the agronomy teleconferences with Extension specialists, University of Missouri Extension climatologist Pat Guinan said the slow Read More
Carl Casale of CHS
Industry NewsCooperative CHS Reports Net Income Of $471.5 Million Fo…
April 20, 2015
CHS Inc., the nation’s leading farmer-owned cooperative and a global energy, grains and foods company, has announced company net income Read More
Industry NewsCHS Insurance Names New Director Of Sales
April 17, 2015
Bryan Lewis has been named director of sales for CHS Insurance, the nation’s largest agribusiness insurance broker and full-service insurance Read More
Mature Waterhemp in Corn
HerbicidesGenetic Literacy Project: There’s No Such Thing A…
April 17, 2015
Read the latest “analysis” on GMOs from Consumer Reports and you’ll “learn” that glyphosate, the chemical developed by Monsanto (its Read More
HerbicidesNew Resistance To 2,4-D Discovered In Australia
April 17, 2015
In a world-first case of herbicide resistance, researchers have confirmed that sowthistle weed in the south east of South Australia Read More
ManagementNews From RTP Company Visits and Growers Buying Older S…
April 16, 2015
Paul Schrimpf and Eric Sfiligoj discuss recent trips to the Research Triangle Park area and market seed sales trends. Read More
soybean field
StewardshipNew ASABE Standard Establishes Framework For Sustainabl…
April 16, 2015
The American Society of Agricultural and Biological Engineers (ASABE) has initiated a project to develop a new standard to establish Read More
MicronutrientsSouthern States: An Inside Look At Our Tissue Sampling …
April 15, 2015
Remember learning about the food pyramid in school? The nutritional diagram recommends the proper amount of nutrients you need on Read More
Industry NewsArysta Adds New U.S. Fungicides Marketing Manager
April 15, 2015
Arysta LifeScience North America recently hired Deneen Sebastian as its Marketing Manager for U.S. Row Crops, Fungicides. Most recently, Sebastian Read More
FungicidesVerdesian Launches Phosphite-Based Cereal Fungicide
April 14, 2015
A new, phosphite-based fungicide designed for improved suppression of deoxynivalenol (DON) in wheat and barley infected by Fusarium head blight Read More
Mature Waterhemp in Corn
HerbicidesSURVEY: Close To 90% Of Growers Battle Weed Resistance
April 14, 2015
Herbicide resistance management continues to be a priority for corn and soybean growers, and they’re working together more effectively to Read More
CropLife 100Pinnacle Agriculture Acquires Minnesota Retailer
April 14, 2015
Pinnacle Agriculture Holdings, LLC, ranked No. 6 on the CropLife 100,  has successfully acquired Liebl Ag, LLC in Ada, MN.  Read More
StewardshipFMC Corp. Joins Sustainable Agriculture Alliance
April 14, 2015
FMC Corp. has joined Field to Market: The Alliance for Sustainable Agriculture, a multi-stakeholder initiative working to define, measure and Read More
Industry NewsArysta Adds Two To Goëmar Sales Team
April 14, 2015
Arysta LifeScience North America recently announced two new additions to the Goëmar sales team: Steve Kelly, Technical Service Manager – Read More
Valley Variable Rate Irrigation
Precision AgVariable Rate Irrigation Gains Followers
April 14, 2015
Irrigation systems have had the ability to apply different amounts of water throughout a field for decades, using timers that Read More
CropLife 100CHS, Aurora Cooperative Complete Fertilizer Storage, Gr…
April 13, 2015
CHS Inc., the nation’s leading cooperative and ranked No. 5 on the CropLife 100, and Aurora Cooperative (ranked No. 21) Read More