Weed Worries Worsening

Giant Ragweed

According to most researchers, finding herbicide-resistant weeds is becoming easier with each passing year. “There has been a steady increase in weeds resistant to some of our best herbicides since 1999,” says Dave Stoltenberg, professor at the Department of Agronomy for the University of Wisconsin-Madison. “Our studies found that there was 0% of giant ragweed showing resistance in 1999. In 2005, this number increased to 23%.”

In fact, giant ragweed could be the weed to watch in 2007. By most accounts, the presence of giant ragweed in crop fields can lead to yield losses of 45% to 70% in soybeans and 10% in corn, primarily because of its ability to grow up to 1 inch per day during its peak growth stage.

“Giant ragweed has a number of characteristics that make it a ‘great’ weed, and inherently difficult to control,” says Mark Loux, professor and Extension specialist for the Department of Horticulture and Crop Science at The Ohio State University. “It emerges from late March through early July in Ohio, and management programs need to address this long period of emergence,”

Since giant ragweed is usually present in fields at planting, it should be controlled using a combination of preemergence and postemergence herbicides. In soybeans, this should include a preplant burndown herbicide treatment using 2,4-D ester plus either glyphosate or paraquat. Next, in fields with a history of giant ragweed control problems, post applications should utilize either glyphosate, fomesafen, lactofen, or cloransulam-methyl. In fields with a history of general weed control problems, this should be followed up by a second post application of glyphosate approximately three weeks later. With corn, a similar multiple herbicide approach should be used.

Other Weeds To Watch

With more continuous corn being projected for 2007, researchers predict that tall waterhemp will become more of a problem. According to John Long, district agronomist for Mycogen Seeds, this weed also is developing a tendency to emerge later during the growing season.

To combat this, Long suggests retailers conduct a thorough scouting of fields to determine how severe a tall waterhemp outbreak there might be. Once this is established, applying a half rate of preemergence herbicide is advised.


Leave a Reply

Herbicides Stories

HerbicidesBREAKING: EPA Pulls Registration On Dow’s Enlist Duo
November 25, 2015
EPA on Wednesday withdrew approval of a controversial new weed killer to be used on genetically modified corn and soybeans, Read More
Cornfield near Sioux City Iowa
HerbicidesDow AgroSciences Sells Oxyfluorfen Herbicides To China’s Nutrichem
November 16, 2015
Dow AgroSciences LLC, a wholly owned subsidiary of The Dow Chemical Co., has entered into definitive agreements under which Nutrichem Read More
HerbicidesEuropean Agency Declares Glyphosate Unlikely To Cause Cancer
November 13, 2015
Glyphosate is unlikely to cause cancer in humans, the European Food Safety Authority (EFSA) said on Thursday, and the agency Read More
Enlist spray Demo
Crop InputsGrowers See Benefits Of Enlist Weed Control In First Year Of Commercial Use
November 12, 2015
Growers report seeing strong stands, good ear length and fill, full pods and clean fields where Enlist corn and Enlist soybeans Read More
Top 100 Articles
CropLife 100United Cooperative Acquires Four ADM Wisconsin Facilities
November 12, 2015
United Cooperative, based out of Beaver Dam, WI, recently acquired four grain and agronomy locations from Archer Daniels Midland (ADM) Read More
CropLife 100BRANDT Car Makes NASCAR Xfinity Series
October 29, 2015
BRANDT will join JR Motorsports with driver, Justin Allgaier, for the 2016 NASCAR Xfinity (NXS) Series season. Allgaier will pilot Read More
CHS Building exterior
CropLife 100CHS Leaders Help Shape Succession Report
October 22, 2015
Succession planning was listed as a main concern of cooperative leaders at this summer’s 15 regional CHS owner town hall Read More
Fall Harvest
CropLife 100Pinnacle Purchases Eight Regional Seed Companies
October 12, 2015
Pinnacle Agriculture Holdings has announced the purchase of eight regional seed companies to advance its seed business. Pinnacle has acquired: Read More
MRM Agricultural Service
CropLife 100Pinnacle Acquires CropLife 100 Ag Retailer
October 8, 2015
Pinnacle Agriculture Holdings, LLC has successfully acquired the Missouri-based agronomy business of MRM Agricultural Service, LLC and its affiliates (MRM). Operating Read More
Eric Jenks, Wilbur-Ellis
CropLife 100Wilbur-Ellis Opens Dry Fertilizer Storage And Blending Facility In Washington
October 8, 2015
Wilbur-Ellis Co., ranked No. 4 on the CropLife 100, has constructed and opened a 22,000-ton dry fertilizer storage and blending Read More
Latest News
HerbicidesBREAKING: EPA Pulls Registration On Dow’s Enlist …
November 25, 2015
EPA on Wednesday withdrew approval of a controversial new weed killer to be used on genetically modified corn and soybeans, Read More
FertilizerYara Tampa Ammonia Terminal Garners ResponsibleAg Honor…
November 25, 2015
Yara has received its first ResponsibleAg Certification for its Tampa, FL, Ammonia terminal location. This achievement demonstrates Yara’s commitment to Read More
ManagementReviewing The Top Ag Stories For 2015
November 24, 2015
Editors Eric Sfiligoj and Paul Schrimpf discuss the most noteworthy events from this past year in agriculture. Read More
EmployeesAgriculture Jobs May Be Plentiful, But New Grads Are Sc…
November 24, 2015
Close to 60,000 jobs are set to open up in agriculture each year for the next five years, but there's not enough grads to fill them. Read More
Radish cover crop
StewardshipCover Crops Guide Helps Growers Improve Water Quality
November 23, 2015
A publication that teaches growers the advantages of using cover crops to improve soil health and crop yields has won Read More
Crop InputsThe Andersons’ Products Receive California Organi…
November 23, 2015
The Plant Nutrient Group of The Andersons, Inc. announced today that its Humic DG and Black Gypsum DG products are Read More
Eric SfiligojNew European Study Seems To Support Glyphosate Safety
November 23, 2015
Looking at any international news over the past few years, it might seem as if the European Union (EU) is Read More
Toggle Biostimulant corn roots
Crop InputsTwo New Biostimulants Added To United Suppliers’ …
November 20, 2015
Winfield US announces the launch of two new products in the United Suppliers portfolio for the 2016 crop season, Optify Read More
StewardshipNRDC Report: Cover Crops Contain Vast Benefits
November 19, 2015
As harvest season ends and farmers in the United States ready themselves for winter, one small change could make a Read More
Fall Harvest
Seed/BiotechArysta Launches New Seed Protectant
November 19, 2015
As spring wheat growers begin planning for a strong start to their season, Arysta LifeScience North America announces RANCONA V Read More
Crop InputsInocucor Receives U.S. Patent For Microbials
November 19, 2015
Inocucor Technologies Inc., the Montreal-based agriculture biotech company, was issued patent No. 9,175,258 by the U.S. Patent and Trademark Office to protect Read More
ManagementSyngenta Rumors and ARA 2015 Preview
November 19, 2015
CropLife Editor Eric Sfiligoj looks at the latest rumors involving Syngenta selling its crop protection business and talks about events Read More
EquipmentAGCO Announces Finalists For Operator Of The Year Honor
November 19, 2015
AGCO Corp. has announced the four top operators chosen as finalists for AGCO’s 10th Annual Operator of the Year program, Read More
High Plains Aquifer
StewardshipStudy: High Plains Aquifer Overall Usage In Decline
November 18, 2015
A new Kansas State University study finds that the over-tapping of the High Plains Aquifer’s groundwater beyond the aquifer’s recharge Read More
Golden Harvest Corn healthy leaves
FungicidesArysta Launches New Corn And Soybean Fungicide
November 17, 2015
Arysta LifeScience North America has recently launched ZOLERA FX Fungicide. The highly systemic, powerful fungicide delivers broad-spectrum disease control with Read More
Young corn plants in soil
Crop InputsBioAg Alliance: Microbials Targeted For 250-500 million…
November 17, 2015
Monsanto and Novozymes have announced a new 2025 acreage target that will guide the companies’ microbials business for the next Read More
Syngenta Sign
Crop InputsSyngenta Still Being Eyed For China Takeover
November 16, 2015
China National Chemical Corp. approached sovereign wealth funds including China Investment Corp. to help pay for a potential acquisition of Read More
Cedar Country Cooperative
Eric SfiligojCooperative Consolidation Continues
November 16, 2015
As I put this enewsletter column together, we’ve just put the finishing touches on our magazine’s annual CropLife 100 report. Read More