Fungicide Resistance Found In Soybean Field

Research conducted by the University of Illinois (U of I) and the University of Tennessee confirms that the fungus that causes frogeye leaf spot (FLS) of soybean, Cercospora sojina, has shown resistance to strobilurin fungicides in a Tennessee soybean field.

“Strobilurin fungicides belong to the chemistry class known as the quinone outside inhibitors (QoIs), which are the most widely used group of foliar fungicides applied to field crops to manage plant diseases,” says Carl Bradley, U of I Extension plant pathologist.

These fungicides can be sold as one-active ingredient products such as Headline (BASF Corp.) or Quadris (Syngenta Crop Protection) or in products that combine them with a fungicide in a different chemistry class known as the demethylation inhibitors, sometimes referred to as triazoles, he says. Products that include a strobilurin-triazole combination of active ingredients include Quilt (Syngenta Crop Protection) and Stratego (Bayer CropScience).

Strobilurin fungicides have been deemed high risk for fungal pathogens developing resistance to them. This high-risk status has been determined by the Fungicide Resistance Action Committee (FRAC), an international committee that evaluates fungicides’ likelihood of developing resistance.

“Plant pathogenic fungi developing resistance to strobilurin fungicides is not new,” Bradley says. “This has already occurred in potatoes and other crop and disease systems where multiple fungicide applications occur during the growing season.”

In the major soybean production areas in the U.S., soybean fields are generally treated once during the season with a fungicide (if treated at all), Bradley says.

“However, we were somewhat surprised to find resistance so soon,” he adds. “Every time you apply a fungicide, you increase the selection pressure and the opportunity to select out individuals in the pathogen population that have resistance or reduced sensitivity to the fungicide.”

In 2008, Bradley’s laboratory began a project funded by the Illinois Soybean Association to develop a fungicide resistance monitoring program. Since then, his lab has been obtaining samples, conducting tests and monitoring isolates collected from Illinois.

“This year, we decided to cast our net a little farther, particularly in the South,” he says. “In Tennessee, FLS is a major soybean foliar disease. Dr. Melvin Newman of the University of Tennessee sent me samples from a field that had been sprayed twice with strobilurin fungicides but still continued to have high levels of FLS, which was an indication of potential fungicide resistance.”

Bradley’s team confirmed that the sensitivity of the Tennessee isolates was reduced as compared to the sensitivity of baseline isolates.

In petri dish tests conducted at the U of I, spores from isolates of Cercospora sojina germinated in the presence of high concentrations of azoxystrobin, pyraclostrobin, and trifloxystrobin, which are the strobilurin active ingredients found in Quadris, Headline, and Stratego.

“This proved we were dealing with isolates that have reduced sensitivity to strobilurin fungicides,” he said. “Currently, Tennessee is the only state in which we have documented isolates like these, but we are continuing to perform tests on isolates collected from fields in Illinois and other states.”

(Source: Jennifer Shike, College of Agricultural, Consumer and Environmental Sciences, University of Illinois)

Leave a Reply

Fungicides Stories

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
FungicidesFMC Launching New In-Furrow Combo Insecticide/Fungicide
November 9, 2015
FMC is launching Ethos XB insecticide/fungicide, the first of its kind, integrated in-furrow product for insect and disease control. Formulated Read More
FungicidesNew Corn Disease Confirmed In Illinois
October 7, 2015
Symptomatic corn leaf samples from Champaign County, IL, have been confirmed positive for the bacterium Burkholderia andropogonis (Pseudomonas adropogonis (Smith) Read More
Poor wheat stand diminished by diseases
FungicidesThe Importance Of Wheat Seed Treatments
September 18, 2015
Fungicide seed treatments help to reduce losses caused by seed transmitted and soilborne fungal diseases of wheat, according to the 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