Key Factors Impacting Herbicide Injury To Corn

During the past week, the number of observations and inquiries related to corn injury from herbicides increased, said University of Illinois associate professor of weed science Aaron Hager.

Instances of corn injury appear to be fairly widespread across the state. Direct application of postemergence herbicides and persistence of herbicides applied last season appear to be responsible for much of the injury.

“Many postemergence corn herbicides routinely cause some corn injury,” said Hager. “Some growers, however, have the impression that this year there is a bit more injury than usual.”

Hager said that several factors can affect the sensitivity of corn to injury from postemergence herbicides, including:

  • Hybrid: Hybrids have varying sensitivity to herbicides labeled for use in corn. For example, some corn hybrids are sensitive to specific ALS-inhibiting herbicides and tend to exhibit considerable injury following herbicide application. Many corn herbicide labels (especially labels of postemergence corn herbicides) carry warnings that certain corn hybrids could be sensitive to the active ingredient.
  • Environmental conditions: High air temperatures and relative humidity levels favor rapid absorption of foliar-applied herbicides, but some environmental conditions can induce crop stress, slowing the rate at which the crops metabolize the herbicide and leading to increased herbicide-related injury. For example, cool air temperatures and wet soil can induce crop stress.
  • Spray additives: Crop response may be enhanced when spray additives are applied with a postemergence herbicide or tankmix combination because of the increased rate of herbicide absorption into the plant. Be sure to read all label suggestions and precautions related to spray additives that should be either included or avoided when applying herbicides postemergence.
  • Contamination: Herbicide residues from prior applications may be applied inadvertently with the postemergence corn herbicide. These residues, either alone or in combination with the postemergence corn herbicide, may enhance the amount of corn injury. The type of contaminant and the dose at which it is applied affect the severity of the corn response to spray contamination.

Soil residues of herbicides applied during the previous growing season (carryover) appear to be another source of corn injury. Herbicide persistence in the soil, and the rate of chemical or microbial degradation, are influenced by many factors, including the specific chemistry of the herbicide and edaphic factors.

The soil pH is a critical factor affecting the persistence and degradation of many herbicides, including sulfonylurea and triazine herbicides, because it affects the rate of chemical degradation via hydrolysis. High soil pH (7.0 or more) may slow the dissipation of certain herbicides by reducing the hydrolysis rate. Even when soil moisture is adequate, triazine and sulfonylurea herbicides degrade more slowly in soils with high pH.

Soil moisture also influences the efficacy and persistence of soil-residual herbicides. Populations and activity of soil microorganisms that are responsible for microbial degradation of herbicides are greatly reduced when soil moisture is limited. Moreover, more herbicide is adsorbed to soil colloids in dry soils, making it unavailable for plant uptake and degradation by soil microbial populations.

“The very dry soil conditions encountered during parts of the 2011 growing season likely slowed the degradation of some soil-residual herbicides, particularly those degraded by soil microorganisms,” said Hager. Dry soil conditions early in 2012 allowed for unusually early corn planting, which in some instances occurred before the end of the rotational interval of the herbicide used in 2011.

Hager said there have been several reports of corn injury that appear to be caused by fomesafen carryover. Veinal chlorosis or necrosis, which causes a striping effect on the leaves, is the most common of these symptoms.

“In some instances, the leaf veins almost appear clear or transparent, but the root system of affected plants usually shows no symptoms unless the foliar symptoms are extremely severe,” he explained.

Because of the fomesafen’s soil persistence and corn’s sensitivity to fomesafen residues, the labels of most products that contain it, including Flexstar, Flextar GT and Prefix, indicate a 10-month rotational interval for corn.

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
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 Expands Sanders Brand To Nine Southern States
February 27, 2015
Pinnacle has acquired Hopkins Seed and Chemical in Qulin, MO, which expands the company's Sanders brand to nine Southern states. Read More
CropLife 100Pinnacle Launches New Providence Agriculture Location In Indiana
February 27, 2015
Pinnacle Agriculture Holdings — ranked No. 6 on the CropLife 100 — has established a new retail location in New Castle, IN, which will operate as part of Pinnacle's Providence Agriculture brand. Read More
CropLife 100Cooperative CHS Returns $518 Million To Owners
February 23, 2015
The 2015 cash return to owners is based on CHS net income of $1.1 billion, the company's second highest on record. Read More
corn field
CropLife 100The Andersons’ Humic DG Now Available In Canada
February 13, 2015
The Andersons, Inc. Turf & Specialty Group has announced its Humic DG product is now available to customers in the Canadian turf, agriculture and horticulture markets. Read More
Farmer on tablet
CropLife 100Southern States Co-op: An Inside Look At Our Aerial Imagery Program
February 8, 2015
Now is as good a time as any to explore the basics of what a retail aerial imagery program looks like today. Read More
CropLife 100Wilbur-Ellis Inks Satellite Imagery Agreement
February 3, 2015
Wilbur-Ellis Company has reached an agreement with Planet Labs to bring satellite imagery to the AgVerdict software platform. Read More
Latest News
CropLife 100Pinnacle Expands Sanders Brand To Nine Southern States
February 27, 2015
Pinnacle has acquired Hopkins Seed and Chemical in Qulin, MO, which expands the company's Sanders brand to nine Southern states. Read More
CropLife 100Pinnacle Launches New Providence Agriculture Location I…
February 27, 2015
Pinnacle Agriculture Holdings — ranked No. 6 on the CropLife 100 — has established a new retail location in New Castle, IN, which will operate as part of Pinnacle's Providence Agriculture brand. Read More
Management2,4-D Celebrates 70 Years; GROWMARK Uses Super Bowl Ad …
February 27, 2015
Jim Gray, executive director of the 2,4-D Research Task Force, lays out planned activities to mark the chemistry’s 70th anniversary. Read More
HerbicidesUniversity Of Arkansas Flag The Technology Program Adds…
February 27, 2015
Started in 2010, the Flag the Technology program provides a visual reference for applicators to distinguish between fields planted with different herbicide-tolerant trait technologies. Read More
Luckey Farmers, Inc.’s Berkey Farm Center
Industry NewsLuckey Farmers’ Berkey Branch Certified In 4R Nut…
February 26, 2015
The 4R Nutrient Stewardship Certification Program has announced Luckey Farmers Inc.’s Berkey Farm Center in northwest Ohio has been added to its growing list of nutrient service providers to achieve certified status. Read More
Crop InputsWinField Unveiling NutriVision Technology, Ascend Dry F…
February 24, 2015
New for 2015 are NutriVision Technology, a unique tool for monitoring in-season plant nutrient availability, and Ascend WSG plant growth regulator, a new dry formulation of Ascend plant growth regulator. Read More
FertilizerNew Formulation Of NutriSphere-N Protects High Volume U…
February 24, 2015
Verdesian Life Sciences is launching NutriSphere-N HVTM, a new polymer formulation of the proven NutriSphere-N Nitrogen Fertilizer Manager that protects high-volume applications of UAN. Read More
EquipmentIowa Ag Secretary Northey Names Hagie Water Quality Lea…
February 24, 2015
Iowa Secretary of Agriculture Bill Northey has named Hagie Mfg. as a recipient of the Secretary’s Water Quality Initiative (WQI) Leader Award. Read More
FungicidesEvito Fungicide Gives Canadian Wheat Growers New Diseas…
February 24, 2015
EVITO fungicide from Arysta LifeScience North America gives Canadian wheat and barley growers a new option for disease control. Read More
Eric SfiligojThe Commodity Classic Turns 20
February 23, 2015
Two decades in, this annual gathering of all things agriculture has become a must-see event. Read More
CropLife 100Cooperative CHS Returns $518 Million To Owners
February 23, 2015
The 2015 cash return to owners is based on CHS net income of $1.1 billion, the company's second highest on record. Read More
ManagementCropLife Retail Week: On The Road Edition
February 20, 2015
Editors Paul Schrimpf and Eric Sfiligoj discuss their recent trips to the National Farm Machinery Show in Louisville and the Read More
Crop InputsLand O’Lakes Acquires FLM+ Assets
February 19, 2015
FLM+ will become a wholly owned subsidiary of Land O'Lakes, Inc., and the company will retain its employee base after closing of the deal, which is scheduled for the second quarter of the year. Read More
Seed/BiotechUnited Suppliers, Stine Seed Form Marketing Alliance
February 19, 2015
The new alliance will greatly expand sales opportunities for Stine Seed with the United Supplier Seed Link Owners. Read More
Crop InputsVilsack To Deliver Commodity Classic Keynote Address
February 19, 2015
The secretary will deliver a keynote address to several thousand farmers and ag allies during the event's General Session, to be held Friday, February 27, in Phoenix, AZ. Read More
Crop InputsSoybean Storage Tips
February 19, 2015
On-farm storage of soybeans requires some special considerations compared to corn. Read More
Monsanto Sign
Crop InputsBioAg Alliance Delivers Promising Field Trial Results
February 19, 2015
In its first full year of field trials, the BioAg Alliance reported that the top 10 microbial strains tested in corn and soybeans showed very promising results. Read More
National Farm Machinery Show overview
EquipmentNational Farm Machinery Show Attendance Up By 16K
February 18, 2015
The 2015 event saw the second highest attendance total of all time as 310,589 attendees that included exhibitors and agribusiness professionals traveled to the Kentucky Exposition Center to participate in the nation’s largest indoor ag trade show. Read More