2,4-D Resistant Waterhemp Found In Nebraska

A waterhemp population from southeast Nebraska has been confirmed to be resistant to 2-4-D. The resistant population is believed to be limited to a few fields.

In 2009 the University of Nebraska-Lincoln received a report of a warm season grass field with a waterhemp population that was no longer being controlled by 2,4-D. Seed from this field was collected in 2009 and 2010 and greenhouse dose response trials were conducted to determine if the population was herbicide resistant.

When compared to a susceptible population, the suspect population was 10-fold more tolerant to 2,4-D. In the greenhouse, a dose of 5 fl oz/ac of 2,4-D (Lo-vol ester, 3.8 lb ae/gal) reduced growth of the susceptible population by 50%. In contrast, 54 fl oz/ac were required to reduce the growth of the suspect population by 50%. In a 2011 study conducted in the field where seed from the suspect population was collected, plants were treated with 2,4-D doses of 0.25 to 64 qt/ac (64 times a typical use rate). At 28 days after treatment (DAT), plants treated with 64 qt/ac were stunted compared to untreated plants and showed injury symptoms characteristic of 2,4-D, but were recovering. At 84 DAT, individual plants that had been treated with 64 qt/ac recovered sufficiently to produce seed.

We believe these results warrant labeling this population as “2,4-D resistant.” This is the sixth herbicide mechanism-of-action (Synthetic auxins) to which waterhemp has developed resistance in the United States, and the third reported in Nebraska.

Waterhemp is the predominant pigweed (Amaranthus) species in eastern and south central Nebraska fields and is problematic throughout much of the Corn Belt. It is well adapted to reduced tillage cropping systems that rely primarily on herbicides for weed control. Waterhemp has succeeded because it emerges from May through August, allowing late emerging plants to avoid herbicides.

Waterhemp is a dioecious species, which means that male and female flowers occur on separate plants. Because of this and the large number of seeds produced per female plant, genes favorable for survival under a particular selection pressure (such as repeated use of a specific herbicide) rapidly spread throughout a population. When a single herbicide is used repeatedly over many years, there is a high risk of herbicide resistant populations developing. Since 1993 waterhemp populations have been reported to have evolved resistance to atrazine (Photosystem II inhibitors), imazethapyr and chlorimuron (ALS-inhibitors), fomesafen and lactofen (PPO-inhibitors), glyphosate (Glycines), and mesotrione and tembotrione (HPPD-inhibitors).

Of particular concern are waterhemp populations where individual plants are resistant to three or more herbicide mechanisms-of-action. In these instances, growers have fewer, effective weed management options. When populations with multiple-herbicide resistance are then managed with the one or two remaining herbicide mechanisms-of-action that are still effective, the likelihood of the population evolving resistance to those herbicides is high. The herbicide use pattern in the field where the resistant population was collected included an annual burndown application of atrazine, metolachlor, and 2,4-D followed by a postemergence application of 2,4-D. Research is underway at UNL to determine whether this waterhemp population has developed resistance to additional herbicide mechanisms-of-action.

New technologies that confer resistance to 2,4-D and dicamba (both synthetic auxins) are being developed to provide additional herbicide options for postemergence weed control in soybean and cotton. The development of 2,4-D resistant waterhemp in this field is a reminder and a caution that these new technologies, if used as the primary tool to manage weeds already resistant to other herbicides such as glyphosate, atrazine or ALS-inhibitors, will eventually result in new herbicide resistant populations evolving. This will limit the value of those technologies to farmers.

To minimize the risk of developing herbicide resistant weeds:

  • rotate effective herbicide mechanisms of action,
  • tank-mix multiple effective herbicides, and
  • use effective doses.

Where possible, use an integrated weed management plan that also includes non-chemical weed control options such as crop rotation and tillage. Carefully monitor fields for changes in susceptibility to the herbicides being used and contact a UNL extension office when resistance is suspected. If multiple plants survive in a field, and that species is known to have developed resistance elsewhere to herbicides used in that field, it may be prudent to remove the survivors before they produce seed.

(Source: University of Nebraska-Lincoln and Extension)

Topics:

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 100The Andersons Acquires South Dakota Plant Nutrient Manufacturer Kay-Flo
May 20, 2015
The Andersons, Inc., ranked No. 22 on the CropLife 100, has purchased Kay Flo Industries of North Sioux City, SD. “This Read More
CropLife 100North Central Farmers Elevator, Wheat Growers Unification Approved By Board, Still Awaits Member Approval
May 13, 2015
The Boards of Directors for North Central Farmers Elevator (NCFE) and Wheat Growers (WG) have voted to approve the Unification Read More
CropLife 100AgGateway’s Barcoding Initiative Progressing Nicely
May 8, 2015
According to legend (or Wikipedia), the first step towards modern bar codes came back in 1948, when Bernard Silver, a 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
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
Latest News
Waterhemp in soybean stubble
HerbicidesEPA Signs Off On Monsanto’s Warrant Ultra Premix
May 27, 2015
Soybean and cotton growers looking for new tools to manage weeds will have a new, first-of-its-kind option in 2016 with Read More
Palmer pigweed seedhead in cotton
HerbicidesSTUDY: Weed Diversity Primarily Influenced By Geography
May 27, 2015
The potential long-term impacts of glyphosate-resistant crops on biodiversity of the agricultural landscape have been the subject of controversy. A Read More
Seed/BiotechAgrilead Forms Distribution Alliance With Kansas-Based …
May 27, 2015
Agrilead, Inc. announces the formation of a strategic alliance with KALO, Inc. of Overland Park, KS. Through the alliance, KALO Read More
EquipmentPrecision Tank Announces A&B Welding Acquisition
May 27, 2015
Precision Tank, a specialized tank and equipment manufacturer, announced today the acquisition of A&B Welding of Thompson, IA, a manufacturer Read More
Allied Cooperative Grain Plant
ManagementTraining Program Gives First Responders Skills For Grai…
May 27, 2015
When stored grain forms hard bridges, columns and other irregularities, those working to correct it find themselves at risk of Read More
Industry NewsBASF Sponsors Space Farming Research Project
May 26, 2015
Is it possible to produce large quantities of high quality vegetables on a space station, about 320 kilometers away from Read More
FertilizerTexas Ammonium Nitrate Bill Passes Senate, Heads To Gov…
May 26, 2015
The Texas State Senate gave final approval last Thursday to new regulations for ammonium nitrate, reports The Dallas Morning News Read More
Young corn plants
Industry NewsArysta Europe Details New Organizational Structure
May 26, 2015
Arysta LifeScience Europe recently announced a new organizational structure to leverage its scale and accelerate the company’s growth in this Read More
Syngenta Sign
Eric SfiligojMonsanto-Syngenta Could Hinge On A Judgment Of Solomon …
May 26, 2015
In the bible, the reputation of King Solomon’s wisdom in matters of despite comes from a tale of one child Read More
ManagementA New Sprayer Company & UAV Research In The Spotlig…
May 21, 2015
CropLife’s Paul Schrimpf and Eric Sfiligoj talk about a Dutch sprayer manufacturer entering the U.S. with a super-sized entry and Read More
HerbicidesFirst U.S. Sale Of Enlist Duo Herbicide Made By Dow Agr…
May 21, 2015
Dow AgroSciences has recorded the first U.S. sale of Enlist Duo herbicide with Colex-D Technology. This marks the first commercial Read More
CropLife 100The Andersons Acquires South Dakota Plant Nutrient Manu…
May 20, 2015
The Andersons, Inc., ranked No. 22 on the CropLife 100, has purchased Kay Flo Industries of North Sioux City, SD. “This Read More
EquipmentNORAC Options Coming To TerraGator
May 19, 2015
Utilizing NORAC’s Standard Control technology, boom height control is now available for TerraGators with Airmax Precision 2 and Benson Booms. This Read More
Crop InputsHelena Introduces New Soil Health Product
May 19, 2015
Helena Chemical Co. is helping agricultural producers maximize yields and efficiency with the introduction of Liquid Chisel, a new product Read More
Stewardship4R Nutrient Management Planning Certification Now Avail…
May 19, 2015
The American Society of Agronomy (ASA) and the International Certified Crop Adviser (ICCA) program announce a new specialty certification in Read More
Environmental Defense Fund logo
Paul SchrimpfEnvironmental Defense Fund: Appreciating Partners
May 19, 2015
I WAS deep in the throes of preparation for the Commodity Classic meeting that took place this past February, trying Read More
WebinarsUpcoming Webinars
May 19, 2015
Register for one of our upcoming Webinars or access our archive of past Webinars to view recordings of presentations that may be of interest to you. Read More
Syngenta Sign
Seed/BiotechSyngenta Responds To Lawyer’s Victory Claim In Vi…
May 18, 2015
A plaintiff’s lawyer has issued a public statement claiming that damages have been awarded in the Agrisure Viptera corn lawsuits Read More