Weed Scientist: Giant Ragweed Latest Concern For Farmers

When it comes to weed pests, glyphosate-resistant waterhemp tops the list, but resistant giant ragweed may be the challenger, according to a University of Missouri Extension weed scientist.

“Giant ragweed certainly has my attention,” Kevin Bradley, University of Missouri Extension weed scientist, told pest management field day visitors at MU Bradford Farm. “We’ll focus our research on giant ragweed, both resistant and not.”

Bradley considers the resistant waterhemp a statewide problem. “We’re not focusing on anymore surveys of waterhemp,” Bradley says. “I’m confident it is just about everywhere corn and soybeans are grown.”

On the most recent survey, when waterhemp was tested from 144 locations across the state, 58 percent of the populations were resistant to glyphosate. A new survey tested giant ragweed from 27 farms, with 12 found glyphosate-resistant.

Bradley collects weed seeds in the fall from random fields, not just those suspected of having resistance. The seeds are grown in an MU greenhouse. At various stages weeds are sprayed with different concentrations of glyphosate or ALS herbicides. Those that thrive in spite of herbicide are labeled resistant.

“My concern is not just herbicide resistance, but multiple resistances,” Bradley says.

What started as resistance to glyphosate, the most widely used herbicide, has become resistance to other herbicides. The newly resistant giant ragweed has been found to tolerate high levels of glyphosate and to have at least moderate resistance to ALS herbicides.

“It will take a combination of herbicides to control the resistant weeds,” he says.

At another stop on the MU weed tour, Bradley said best control of weeds is obtained with a two-pass system. Herbicide is sprayed before planting to control overwintering weeds and emerging seedlings. Then the growing crop is sprayed with a post-planting application to control new weeds.

“The majority of the time this two-pass system works best,” Bradley says. “There is a definite yield advantage.”

However, new herbicide combinations with longer life show promise. “A one-pass system that includes a residual herbicide is becoming more popular with farmers,” Bradley says.

At a third stop, Bradley showed off what he calls “research that we can’t say much about.” The soybeans, mostly weed-free, are tolerant to 2,4-D herbicide, an older chemistry that was widely used for years.

“You won’t see this available commercially for a few years,” Bradley predictes. “But the 2,4-D-tolerant soybeans are very robust and tolerate 2,4-D very well.”

(Source: University of Missouri Cooperative Media Group)

Leave a Reply

2 comments on “Weed Scientist: Giant Ragweed Latest Concern For Farmers

  1. Bourquin’s Farm Mkt. & Trading Co., Inc.

    I’m contacting you to let you know we manufacture a weedpulling machine for Organic farmers called the BOURQUIN WEEDPULLER/ORGANIC WEEDPULLER. We would like to encourage you to look at our website, http://www.organicweedpuller.com and see a video of it pulling weeds.
    Then if you have any questions, give us a call.
    Thank you for your time,

    Dan and Shirley Bourquin
    Dan@organicweedpuller.com
    http://www.organicweedpuller.com
    BOURQUIN’S ORGANIC WEEDPULLER
    155 East Willow, Colby, KS 67701
    Phone: 785-462-3300
    Phone: 785-443-2774

  2. Bourquin’s Farm Mkt. & Trading Co., Inc.

    I’m contacting you to let you know we manufacture a weedpulling machine for Organic farmers called the BOURQUIN WEEDPULLER/ORGANIC WEEDPULLER. We would like to encourage you to look at our website, http://www.organicweedpuller.com and see a video of it pulling weeds.
    Then if you have any questions, give us a call.
    Thank you for your time,

    Dan and Shirley Bourquin
    Dan@organicweedpuller.com
    http://www.organicweedpuller.com
    BOURQUIN’S ORGANIC WEEDPULLER
    155 East Willow, Colby, KS 67701
    Phone: 785-462-3300
    Phone: 785-443-2774

Herbicides Stories

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
HerbicidesHerbicides 2014: A Weed Killer For Every Weed
December 2, 2013
As weed resistance continues to proliferate, there are simply more options available than ever before in weed control — with more on the horizon. Read More

Trending Articles

Green Valley Ag facility
Retail FacilitiesGreen Valley Ag Adopts A.J. Sackett’s Precision Fertilizer Blending® Technology At New Facility
July 8, 2014
Sackett's Precision Fertilizer Blending® Technology is making huge strides around the world. Green Valley Ag adopts the technology at its new facility to support its advancing agronomic needs. Read More
Retail FacilitiesWaconia Manufacturing Builds Facility Designed For Speed, Efficiency
July 7, 2014
To make its new hub facility more efficient, Cooperative Elevator enlisted the aid of Waconia Manufacturing. Read More
EquipmentSummer Show Preview 2014: Superior Sprayers Take The Field
July 3, 2014
In this final installment of our coverage of the major categories of Big IRON that retailers can expect to test-drive at this summer’s events, here is a look at 19 sprayers. Read More
Scouting a soybean patch at Green Valley Ag.
EmployeesCropLife Compensation Survey: Battling Talent Drain
July 2, 2014
Retailers too often lose employees to companies outside of agriculture, while recruiting efforts are most often limited to competitors and other ag-focused organizations. Read More
HerbicidesDow AgroSciences Introduces SureStart II Herbicide
June 16, 2014
The enhanced formulation has improved viscosity and increased stability under heat and controls more than 60 high-anxiety grasses and broadleaf weeds found in corn fields. Read More
HerbicidesBASF Investing $270 Million To Expand U.S. Herbicide Production
June 11, 2014
BASF has invested more than $270 million to expand herbicide production capacities in the U.S., including more than 20 new products to be launched over next two years. Read More

Latest News

HerbicidesWillowood To Market Glufosinate
July 28, 2014
Willowood USA recently announced that Federal EPA has approved its technical registration for glufosinate. Read More
InsecticidesHow To Scout For Corn Earworms In Corn
July 28, 2014
In her weekly report, University of Missouri Agronomy Specialist Jill Scheidt discusses what to look for when scouting for corn earworm. Read More
Crop InputsDuPont Pioneer, Weyerhaeuser Enter Technology License A…
July 28, 2014
The agreement brings together agricultural and forestry know-how to sustainably improve crop productivity for corn growers around the world. Read More
EquipmentAGCO Launches Global iPad App
July 28, 2014
The free AGCO Global iPad App can be downloaded from the Apple iTunes Store and features the full family of RoGator self-propelled sprayers and TerraGator high-floatation spreaders. Read More
Eric SfiligojYuma Centennial Ag Supply Earns 2014 National Environme…
July 28, 2014
Colorado-based ag retailer receives top trophy in 24th annual DuPont Crop Protection/CropLife ceremony. Read More
CropLife 100Pinnacle Forms Alliance With Wildlife Managment, Seed O…
July 25, 2014
The strategic alliance will provide Tecomate with key wildlife products, processing facilities, distribution centers and sales through Pinnacle’s ever-growing retail network. Read More
ManagementFranken Presses White House On RFS Support
July 25, 2014
Al Franken and a group of Senate democrats recently met with senior White House official John Podesta to urge the administration to change its position on an EPA proposal. Read More
ManagementASA, FarmLink To Launch ‘Operation Benchmark̵…
July 25, 2014
The American Soybean Association (ASA) and FarmLink are teaming up to help farmers close the $11 billion gap between what they harvested in 2013 and what they could harvest annually. Read More
StewardshipNorthey: Farmers Commit $1.4 Million to Try New Water Q…
July 25, 2014
The practices that are eligible for funding include cover crops, no-till or strip till and using a nitrification inhibitor when applying fall fertilizer. Read More
Precision AgFarmers Learn How Changing World Will Impact Iowa
July 24, 2014
Technology and understanding global consumer demand for Iowa farm products brought hundreds of farmers and agribusiness leaders to Ames recently for the annual Iowa Farm Bureau Federation Economic Summit. Read More
HerbicidesPurdue: Late Season Weeds May Require Manual Removal
July 24, 2014
Hand-rouging and pulling late season weeds by hand may be the best way to remove them, more so than using a herbicide, a Purdue Extension weed scientist says. Read More
Soybean Field
InsecticidesTransform WG, Closer SC Insecticides Receive R&D 10…
July 23, 2014
Dow AgroSciences has received the award from R&D Magazine for Transform WG insecticide and Closer SC insecticide with Isoclast active. Read More
EquipmentKinze, Raven Team Up On 4900 Planter Monitor
July 23, 2014
Kinze Manufacturing announces a partnership with Raven Industries to develop a standalone monitor solution for the Kinze 4900 series planter. With this new Read More
LegislationNew Farm Bill Continues To Confuse As Growers Await USD…
July 23, 2014
The new five-year Farm Bill eliminates many of the direct payments previously payed to growers and could benefit from USDA clarification, reports a Toledo Blade columnist. Read More
EquipmentPrecisionAg.com Relaunches With Responsive Design For M…
July 22, 2014
PrecisionAg, the worldwide leader in precision agriculture information and analysis, announces the launch of its completely redesigned website, PrecisionAg.com. Read More
FungicidesEPA OKs Two Willowood Fungicides
July 21, 2014
The EPA has approved Willowood Azoxy 2SC and Willowood AzoxyProp Xtra. two widely used broad spectrum, preventative fungicides with systemic and curative properties. Read More
Precision AgFarmers Learning Fast As UAVs Take Off
July 17, 2014
Farmers and others interested in how UAVs can be used in agricultural applications were able to learn more about the technology during the recent Precision Aerial Ag Show. Read More
CropLife 100Bobby Knight, Richard Petty To Highlight Ag PhD Field D…
July 17, 2014
Attendees at the July 24 Ag PhD Field Day at Hefty Farms will learn about the latest agricultural technologies, and get a chance to meet legendary sports figures Bobby Knight and Richard Petty. Read More