And Now, Johnsongrass

Two cases of a new glyphosate-resistant weed have been confirmed in the South.

A field in southeast Arkansas is one of the sites and has been confirmed by the University of Arkansas and Monsanto Co. The other confirmation, by specialists at Mississippi State University (MSU) and Monsanto, is near Clarksdale, MI.

The two cases were investigated over the past several months. In initial greenhouse trials conducted by the University of Arkansas and Monsanto, johnsongrass was not controlled with labeled rates of glyphosate. Additional trials will be conducted in the field this season.

“We’re looking at johnsongrass populations in a field where there has been a history of control issues,” says Dr. Bob Scott, University of Arkansas Extension weed scientist. The field in question is owned by a grower near Crittenden County, AR, and has been in continuous Roundup Ready soybeans.

“Our greenhouse trials show differing levels of response including some plants that survive following application above labeled rates of glyphosate. Additional populations suspected to be resistant were also tested but shown susceptible to Roundup in testing,” says Scott. “The resistant populations are being controlled well with selective chemistry. We will continue working with the grower on control methods and recommendations.”

Monsanto’s technology development team has been working with a grower and his dealer outside of Clarksdale, MS, on a field with johnsongrass control issues as well. Dr. Trey Koger and Dr. Dan Poston of MSU’s Delta Research & Extension Center are working with the company on recommendations.

“The farm where glyphosate-resistant johnsongrass was found in the Delta has responded well to applications of graminicides,” Koger explains. “We are working with the grower to get control of this population before it spreads by combining various methods including chemistry and equipment inspection.”

Like Scott, Koger says other populations have been screened as well. “We have screened several populations of johnsongrass in the mid-Delta for potential resistance to glyphosate,” says Koger. “They all turned out to be susceptible to glyphosate in greenhouse trials. We determined low control levels in the field were attributed to extremely dry conditions at time of glyphosate application.”

Dr. Jennifer Ralston, U.S. chemistry technical lead for Monsanto agrees a program approach is best. “We are working with these university experts to provide growers with the best management practices,” she says. “To maintain the efficacy of the herbicide and value of the technology, we recommend growers scout fields and utilize additional modes of action that complement the Roundup Ready system to control problem weeds while reducing the likelihood of developing performance issues.”

The company and academics recommend growers adopt best management practices to help minimize the risk of developing resistant weeds, including:

  • Start with a clean field by either utilizing a burndown herbicide or tillage to control weeds early.
  • Use Roundup Ready technology as the foundation of a total weed management program.
  • Add other herbicides or cultural practices where appropriate as part of the Roundup Ready cropping system.
  • Use the right herbicide rate at the right time.
  • Control weeds throughout the season and reduce the weed seed bank.

Leave a Reply

Featured Stories

Eric SfiligojMAGIE 2014: A ShowStopping Event
August 8, 2014
The kick-off to the summer show season, Midwest AG Industries Exposition (MAGIE), takes place next week in Bloomington, IL. Read More
EmployeesAsmark Institute Dedicates New Training Center To Ford West
August 6, 2014
The Asmark Institute plans to recognize the retired industry leader's years of service to the fertilizer industry at the new state-of-the-art facility in Owensboro, KY. Read More
StewardshipMonsanto Joins Panel Of Innovators To Advance Research On Climate Change And Farming
July 30, 2014
Monsanto Co. and The Climate Corp., its division, recently joined a roundtable of experts at the White House to share ideas and research approaches to help the world’s farmers manage and adapt to the impact of climate change on the global food supply. Read More
Eric SfiligojYuma Centennial Ag Supply Earns 2014 National Environmental Respect Award Honors
July 28, 2014
Colorado-based ag retailer receives top trophy in 24th annual DuPont Crop Protection/CropLife ceremony. Read More

Trending Articles

EquipmentAdvance Your Technology IQ At MAGIE
August 13, 2014
The Midwest AG Industries Exposition (August 20-21) is the place you need to be to see, study and evaluate how new advances in the equipment, operations, crop protection and fertility sectors can help your business prosper. Read More
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
StewardshipMichigan Agriculture Leaders On Toledo Water Ban: We Want To Be Part Of The Conversation
August 8, 2014
Leaders of Michigan agricultural organizations said Thursday that the government should not have a “knee-jerk reaction” based on last weekend’s water ban in Toledo due to fertilizer run-off in Lake Erie. Read More
CropLife 100BRANDT Acquires Lemon Ag Services
August 4, 2014
The acquisition of Lemon Ag fits BRANDT’s aggressive corporate strategy of providing superior agronomic advice and services for customers in central Illinois. Read More
Eric SfiligojThe Resurgence Of Crop Protection
August 4, 2014
Plenty of new offerings over the next few years should see a rebirth for the crop protection products category in terms of market share. Read More
LegislationUSDA Implements Key Farm Bill Crop Insurance Provision
July 30, 2014
The new Supplemental Coverage Option, available through the federal crop insurance program and set to begin with the 2015 crop year, is designed to help protect producers from yield and market volatility. Read More

Latest News

ManagementNCGA DuPont New Leaders Program Enters Sophmore Season
August 20, 2014
The National Corn Growers Association and DuPont are pleased to announce the second year of the NCGA DuPont New Leaders Program. Read More
FungicidesVerdesian Links Up With Mitsui, Hokusan
August 20, 2014
Mitsui Chemicals Agro, Inc., and Hokusan Co., announced the signing of an exclusive licensing agreement allowing Verdesian Life Sciences global access to its patented technology for suppressing mycotoxin contamination in wheat and barley. Read More
SprayersUniversity Of Illinois Introduces New Spray App
August 18, 2014
University of Illinois Extension has released a new smartphone app for making sprayer-related calculations. Pesticide Spray Calculator, or Spray Calc, Read More
Crop InputsSyngenta Names New Manager Of Federal Government Relati…
August 18, 2014
Laura Wood Peterson has joined Syngenta as manager of federal government relations, based in Washington, DC. Read More
ManagementExpert To Discuss Farmland Value, Rent At Farm Science …
August 18, 2014
While cropland values in Ohio increased in the past two years, they have remained flat in 2014, declining in some cases, according to an Ohio State University agricultural economist. Read More
EquipmentDeere Announces Factory Layoffs
August 18, 2014
Deere & Co. has announced it will reduce the size of its manufacturing workforce at some agricultural equipment factories in response to current market demand for its products. Read More
HerbicidesNew DuPont Afforia Herbicide Gives Crops A Clean Start
August 18, 2014
DuPont Afforia is a preplant herbicide for soybeans and other field crops that provides excellent burndown and residual control of many challenging weeds, such as marestail and waterhemp. Read More
Equipment21 Products Showcased At MAGIE 2014
August 18, 2014
The annual Midwest AG Industries Exposition is upon us. Here is CropLife IRON's look at some of the products visitors can expect to see at this week's event. Read More
EquipmentAGCO Seeks Nominations For 2014 Operator Of The Year
August 15, 2014
Ag retailers throughout the U.S. and Canada are encouraged to nominate their best applicators. Read More
EquipmentAdvance Your Technology IQ At MAGIE
August 13, 2014
The Midwest AG Industries Exposition (August 20-21) is the place you need to be to see, study and evaluate how new advances in the equipment, operations, crop protection and fertility sectors can help your business prosper. Read More
ManagementCropLife’s Buyers’ Guide Issue Now Availabl…
August 13, 2014
One of our most read issues of the year — the August Buyers' Guide — is ready to download on the iPad. This popular issue features equipment for "In The Field," "At The Plant" and "In The Office." Read More
WebinarsWebinars On Demand
August 13, 2014
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
HerbicidesBASF: Fall Burndown Benefits Go Beyond Weed Control
August 12, 2014
While unpredictable weather may delay application timing of spring herbicides, more growers are adding a burndown application in the fall Read More
HerbicidesScouting Key To Next Season’s Soybean Herbicide P…
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
StewardshipNitrogen Efficiency Supports Environmental Stewardship
August 12, 2014
As growers prepare for another harvest, it’s important to consider how nitrogen stabilization not only supports healthy plant growth but also fosters environmental stewardship. Read More
Seed/BiotechMycogen Seeds Introduces 19 New Corn Hybrids For 2015
August 12, 2014
Many of the new hybrids feature Mycogen's SmartStax Refuge Advanced technology for maximum protection of the genetic potential and planting convenience. Read More
HerbicidesDow AgroSciences Introduces Enlist Ahead App For Enlist…
August 12, 2014
Designed for use with the Enlist Weed Control System, the app is a precision agriculture tool for maximizing weed control performance, managing weed resistance and making responsible applications of Enlist Duo herbicide with Colex-D Technology. Read More
CropLife 100CHS Announces Senior Leadership Team Changes
August 12, 2014
Current CHS strategic leadership team member Shirley Cunningham will assume a new role as executive vice president and chief operating officer, Ag Business and Enterprise Strategy. Read More