Waterhemp Showing Greater Glyphosate Resistance

A Purdue Extension weed specialist urges farmers to take necessary steps now to better control yield-reducing waterhemp next year as it spreads through Indiana with increasing resistance to glyphosate.

Farmers need to learn more about waterhemp because it has shown greater resistance to the herbicide the past 2-3 years, Bill Johnson said. The weed has been present in some Indiana field surveys for about 10 years.

“More recently, we’ve had an increasing number of complaints about glyphosate’s failure to control waterhemp in soybean production,” Johnson said. “The number of calls we have been getting on that has essentially doubled each year over the last couple of years.”

Waterhemp now is found throughout Indiana. It is most prevalent in the southern, southwestern, northwestern and east-central portions of the state.

Johnson has produced the educational document “Waterhemp — an Emerging Weed Problem in Indiana” to raise awareness among farmers and help them develop a plan to better control the weed next year. The document, which includes pictures to help farmers identify waterhemp, is available online here.

Waterhemp is among a dozen species in the pigweed, or amaranth, family. Other pigweed found in Indiana includes redroot pigweed, smooth pigweed and Palmer amaranth.

“We’ve had pigweed for a long time, but this one – waterhemp – has really emerged as a major threat to soybean production,” Johnson said.

One waterhemp plant can produce as many as 1 million seeds. Just a few untreated weeds in a field can lead to a major infestation within a couple of years, Johnson said.

Waterhemp is more of a problem for soybeans than it is for corn. A heavy infestation in a soybean field can reduce yields by 30-50 percent, Johnson said.

Waterhemp has proven difficult to control. Although Johnson said pre-emergence herbicides greatly reduce waterhemp density, it emerges throughout the growing season and usually also requires a postemergence herbicide treatment, especially for soybeans.

“It is very common to have to spray a field multiple times to get the waterhemp under control,” Johnson said. “One-pass herbicide programs are not going to be effective on it because it has a very long emergence pattern.”
Because waterhemp is dioecious – male and female flowers on separate plants – two plants always mix genes when they reproduce, increasing genetic diversity within a population and the potential for spreading herbicide resistance and other traits that enable the plant to survive.

Johnson recommended that farmers now going through their fields at harvest time take note of whether waterhemp is present and, if so, the level of density and whether there appears to be more of it this year than last. He said that will help them determine a plan for better controlling it.

Waterhemp first was controlled in the mid-1980s by herbicides known as ALS- and PPO-inhibitors before Roundup Ready soybeans, resistant to glyphosate, were introduced. But glyphosate-resistant waterhemp also has been found in recent years in Illinois and other states in addition to Indiana.

(Source: Ag Answers)

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
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
StewardshipCould Australian Water Trading Approach Fit In Californ…
May 18, 2015
Ten years of drought isn’t a good thing. It doesn’t help the bottom line of farmers or the health of Read More
SpreadersDutch Sprayer Manufacturer To Enter U.S. Market
May 18, 2015
Dutch self-propelled sprayer manufacturer Agrifac Machinery has announced intentions to enter the U.S. market with two models of sprayers available Read More
FertilizerTFI Weighs In On Fertilizer Rail Transport Bill
May 14, 2015
With today’s House Committee on Transportation and Infrastructure as a backdrop, The Fertilizer Institute (TFI) registered its support for policies Read More
ManagementA Visit To The 2015 Environmental Respect Spirit Award …
May 14, 2015
CropLife’s Paul Schrimpf and Eric Sfiligoj talk about a recent visit to the CPS Spirit winner in St. Stephen’s Church, Read More
StewardshipBayer Entomologist Issues Statement On Annual Honeybee …
May 13, 2015
Richard (Dick) Rogers, Principal Scientist / Entomologist, Bayer Bee Care Center for Bayer CropScience LP, today issued the following statement Read More
Crop InputsKansas State Researchers Announce Resistant Kochia Brea…
May 13, 2015
Kansas State University researchers say new research helps explain why an invasive weed is developing resistance to a well-known herbicide, Read More
RR2X soybeans surround untreated check (center)
HerbicidesUSDA Study: Glyphosate Application More Prevalent In So…
May 13, 2015
Glyphosate—known by many trade names, including Roundup—has been the most widely used pesticide in the United States since 2001. It Read More
AdjuvantsHelena Chemical Introduces New Drift Control Adjuvant J…
May 13, 2015
Helena Chemical Co. introduces Justified, an innovative drift control agent designed to improve the performance and precision of spray applications Read More
CropLife 100North Central Farmers Elevator, Wheat Growers Unificati…
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