Update on frogeye leaf spot and strobilurin resistance

decrease font size  Resize text   increase font size       Printer-friendly version of this article Printer-friendly version of this article

Frogeye leaf spot, which is caused by the fungus Cercospora sojina, is an important pathogen of soybean plants. University of Illinois plant pathologist Carl Bradley said that since 2010, strains of the fungus that are resistant to strobilurin fungicide have been found in Illinois and other states.

“In 2012, we detected strobilurin fungicide-resistant strains of Cercospora sojina in several new states, counties, and parishes,” he said. “In total, we have detected strobilurin fungicide-resistant strains of Cercospora sojina in 44 counties or parishes in eight states since 2010.”

This year, Bradley’s research team conducted a soybean foliar fungicide trial at the U of I Dixon Springs Agricultural Center in a field with a history of frogeye leaf spot and a strobilurin fungicide-resistant strain of Cercospora sojina. They applied several different foliar fungicides from different chemistry classes at the R3 soybean developmental stage (beginning pod formation) and evaluated their efficacy in managing frogeye leaf spot.

They found that strobilurin fungicides were not effective, but fungicides from other chemistry classes reduced frogeye leaf spot severity.

What does this mean?

“As we plan for the 2013 growing season, it is important to consider the increasing number of detections of strobilurin fungicide-resistant strains of Cercospora sojina across several soybean-producing states and how this problem might affect frogeye leaf spot management decisions,” Bradley said.

He recommended three management practices to slow down the development of fungicide resistance, which include:

  • Use resistant varieties and cultural practices (crop rotation, tillage) to help manage frogeye leaf spot. If disease levels are kept low using alternative management practices, fungicides may not be needed.
  • Do not rely on only one class of fungicides to control plant diseases. Fungicides from different chemistry classes can be mixed together to reduce the selection pressure on the fungal population.
  • Apply foliar fungicides only to control plant diseases; do not apply them for other reasons. Every time a fungicide is applied, it exerts a selection pressure on the fungal population, and individual fungal isolates may be selected that are not as sensitive to the fungicide. Keeping this selection pressure to a minimum is important in prolonging the effectiveness and lifespan of a fungicide.

Buyers Guide

Doyle Equipment Manufacturing Co.
Doyle Equipment Manufacturing prides themselves as being “The King of the Rotary’s” with their Direct Drive Rotary Blend Systems. With numerous setup possibilities and sizes, ranging from a  more...
A.J. Sackett Sons & Company
Sackett Blend Towers feature the H.I.M, High Intensity Mixer, the next generation of blending and coating technology which supports Precision Fertilizer Blending®. Its unique design allows  more...
R&R Manufacturing Inc.
The R&R Minuteman Blend System is the original proven performer. Fast, precise blending with a compact foot print. Significantly lower horsepower requirement. Low inload height with large  more...
Junge Control Inc.
Junge Control Inc. creates state-of-the-art product blending and measuring solutions that allow you to totally maximize operating efficiency with amazing accuracy and repeatability, superior  more...
Yargus Manufacturing
The flagship blending system for the Layco product line is the fully automated Layco DW System™. The advanced technology of the Layco DW (Declining Weight) system results in a blending  more...
Yargus Manufacturing
The LAYCOTE™ Automated Coating System provides a new level of coating accuracy for a stand-alone coating system or for coating (impregnating) in an automated blending system. The unique  more...
John Deere
The DN345 Drawn Dry Spreader can carry more than 12 tons of fertilizer and 17.5 tons of lime. Designed to operate at field speeds up to 20 MPH with full loads and the G4 spreader uniformly  more...
Force Unlimited
The Pro-Force is a multi-purpose spreader with a wider apron and steeper sides. Our Pro-Force has the most aggressive 30” spinner on the market, and is capable of spreading higher rates of  more...
BBI Spreaders
MagnaSpread 2 & MagnaSpread 3 — With BBI’s patented multi-bin technology, these spreaders operate multiple hoppers guided by independent, variable-rate technology. These models are built on  more...


Comments (0) Leave a comment 

Name
e-Mail (required)
Location

Comment:

characters left


Portable Conveyors

Convey-all portable conveyors are designed to handle your crops gently and efficiently. We offer an extensive line of high capacity ... Read More

View all Products in this segment

View All Buyers Guides

Feedback Form
Feedback Form