Precautions With Late-Season Herbicide Applications

The adverse environmental conditions common across much of Illinois are challenging the performance of many foliar-applied soybean herbicides.

Weeds that survive an initial herbicide application are often resprayed later in the season. However, according to University of Illinois associate professor of weed science Aaron Hager, the likelihood of controlling larger, moisture-stressed weeds continues to decline.

Moreover, herbicides applied late in the season are more likely to persist long enough to injure sensitive rotational crops. Nearly all herbicide labels (soil-applied or postemergence) specify the interval between herbicide application and planting a rotational crop. Some of these restrictions are based solely on time, while others take into account factors such as soil pH and the amount of precipitation received after herbicide application when determining interval length.

“Soil moisture is often the most critical factor governing the efficacy and persistence of soil-residual herbicides,” Hager said. “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.”

Dry soils can also enhance herbicide adsorption to soil colloids, thus rendering the herbicide unavailable for plant uptake and degradation by soil microbial populations. Some herbicide rotational intervals are increased if a specified amount of precipitation is not received by a certain calendar date.

The intervals are established to prevent herbicide residues from reaching levels that will adversely affect the rotational crop. Respecting these intervals becomes particularly important with late-season herbicide applications and when soil moisture is limited.

“Please keep in mind that the labels of almost all postemergence soybean herbicides indicate a preharvest interval or a soybean developmental stage beyond which applications cannot be made,” said Hager.

Labels of some products may indicate both a developmental stage (before soybean bloom, for example) and a preharvest interval. Preharvest intervals indicate the amount of time that must elapse between the herbicide application and crop harvest.

Failure to observe the preharvest interval may result in herbicide residue levels in the harvested portion of the crop in excess of established limits. Moreover, labels on many postemergence soybean herbicides specify that foraging of, or grazing livestock on, treated soybean is not allowed.

Leave a Reply

Herbicides Stories

Giant Ragweed
HerbicidesStudy: Focusing On Weed Seedbank Can Help Manage Herbicide-Resistant Giant Ragweed
January 18, 2017
Researchers writing in the latest issue of the journal Weed Science provide important insights on the control of herbicide-resistant giant Read More
HerbicidesEPA Expands Enlist Duo Herbicide Registration To 34 States
January 13, 2017
The U.S. EPA has expanded the geography for application of Enlist Duo herbicide from 15 to 34 states. This means Read More
HerbicidesHow Does Herbicide Resistance Evolve?
January 6, 2017
Herbicide-resistant weeds have evolved in response to repeated use of herbicides with the same site of action (SOA), according to Read More
Kochia
Herbicides9 Recommendations For Reducing The Risks Of Herbicide Resistance
January 5, 2017
To address the increasing urgent problem of herbicide resistance, the Weed Science Society of America makes the following recommendations: Reduce the Read More
Trending Articles
AgriSync
Matt Hopkins17 Agriculture Apps That Will Help You Farm Smarter In 2017
December 9, 2016
Ag professionals are working smarter, not harder, than ever before. Smart farming technologies have enabled them to reduce costs, maximize Read More
R4023 Sprayer, John Deere
CropLife 100Ag Retail Equipment Report: The Green Party Continues
December 7, 2016
In the annual race for sales in the ag retail equipment marketplace, the color schemes for participants are a little Read More
Mike Stern
Precision AgClimate Corp. CEO Talks Retailer Support For Digital Ag
December 1, 2016
CropLife Magazine’s sister publication, AgriBusiness Global, recently sat down with Mike Stern, CEO of The Climate Corp., following the Monsanto subsidiary’s Read More
Precision AgTrimble Debuts End-to-End FMIS Platform
November 28, 2016
October’s inaugural PrecisionAg Vision Conference left this author with many thoughts and things to ponder in the coming months. Probably Read More
CHS Primeland
CropLife 100The 2016 CropLife 100 Report: Reviewing The Many Bulls And Bears Impacting This Year’s Marketplace
November 28, 2016
For virtually all of 2016, the nation was wholly focused on the big Presidential election. Some folks aligned themselves with Read More
Monsanto sign
Crop InputsMissouri Governor Meets With Bayer CEO To Discuss Monsanto Merger
November 21, 2016
Missouri Gov. Jay Nixon visited Bayer AG global headquarters in Leverkusen, Germany, on November 18 to discuss the proposed Bayer-Monsanto Read More
Latest News
Eric SfiligojNo Alternative Facts: Dicamba Cropping System Applicato…
January 23, 2017
During President Donald Trump’s inauguration, much fuss was made over the use of the term “alternative facts” vs. some of Read More
Young Corn Plants
ManagementTimac Agro USA Acquires Michigan Ag Retailer
January 20, 2017
Timac Agro USA, an agriculture supply company specializing in high-efficiency plant and animal nutrition products, has acquired St. Louis,MI-based A&E Ag, Read More
Soybean field
Crop InputsNufarm Teams Up With John Deere Financial
January 19, 2017
Nufarm and John Deere Financial have teamed up to help farmers grow a better tomorrow. This program helps make purchases Read More
Sonny Perdue
LegislationTrump Formally Picks Perdue As Agriculture Secretary
January 19, 2017
U.S. President-elect Donald Trump officially announced Sonny Perdue as his choice for secretary of agriculture on Thursday, selecting a former Read More
ManagementPresident Trump, Wisconsin Review, and a Dow-DuPont Upd…
January 18, 2017
Editors Paul Schrimpf and Eric Sfiligoj reflect on a new administration, a recent winter show, and crop protection company mergers. Read More
Industry NewsBayer, MS Technologies Get China Approval For Balance G…
January 18, 2017
MS Technologies and Bayer have received import approval from China for Balance GT soybeans. The new Balance GT Soybean Performance Read More
Werner Baumann, Bayer AG, and Hugh Grant, Monsanto
Industry NewsReport: Monsanto, Bayer CEOs Among Latest to Make Trump…
January 18, 2017
The chief executive officers of German chemical giant Bayer AG and U.S. seed behemoth Monsanto, Werner Baumann and Hugh Grant, Read More
Giant Ragweed
HerbicidesStudy: Focusing On Weed Seedbank Can Help Manage Herbic…
January 18, 2017
Researchers writing in the latest issue of the journal Weed Science provide important insights on the control of herbicide-resistant giant Read More
Management3 Financial Trends To Watch In Agriculture
January 17, 2017
I recently had the opportunity to attend a meeting of credit managers for Midwest ag supply and input companies, in part Read More
Andersons Retail Store
CropLife 100The Andersons To Close All Retail Stores; Shutdown Does…
January 16, 2017
In a stunning announcement to the Toledo area, The Andersons Inc. said on Sunday that it would close its two Read More
Trimble TMX-2050 In-Cab Display
Eric SfiligojPrecision To Lead Agriculture In 2017?
January 16, 2017
Another new year is upon us! And I’m certain I speak for many in the agricultural world when I say Read More
Corn
Eric SfiligojThe Mood From Madison? In A Holding Pattern
January 16, 2017
Last week, I had the chance to attend the annual Wisconsin AgriBusiness Classic show in Madison, WI. It’s been a Read More
Syngenta Sign
Crop InputsAccenture Helps Syngenta Transform Its Global Logistics
January 13, 2017
Syngenta, a leading agriculture company, has collaborated with Accenture to design and implement a new digital logistics operating model across Read More
Fall Creek Seth Harden The Nature Conservancy
StewardshipLocal Farmers’ Watershed Initiative: Continuous Improve…
January 13, 2017
The goal in the Big Pine Watershed Project is to more intentionally do what local farmers and responsible ag retailers Read More
HerbicidesEPA Expands Enlist Duo Herbicide Registration To 34 Sta…
January 13, 2017
The U.S. EPA has expanded the geography for application of Enlist Duo herbicide from 15 to 34 states. This means Read More
Olson Ag Enterprise
CropLife 100Wilbur-Ellis Acquires Nebraska Seed Retailer
January 13, 2017
Wilbur-Ellis’ Agribusiness, a recognized leader in precision agriculture technology and the distribution and marketing of plant protection, seed and nutritional Read More
ManagementDeere-Precision Planting Update and the Ag Secretary Wa…
January 12, 2017
Editors Paul Schrimpf and Eric Sfiligoj provide the latest on the court date for John Deere/Precision Planting and the quest Read More
Monsanto sign
Seed/BiotechMonsanto, NRGene Form Agreement For Big Data Genomic An…
January 12, 2017
Monsanto Co. and NRGene have announced that the companies have reached a non-exclusive, multi-year global licensing agreement on NRGene’s genome-analysis Read More