2015
Developing a Comprehensive Management Program for Foliar Diseases of Soybean (Phase II) (Year 1 of 1520-532-5662)
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Contributor/Checkoff:
United Soybean Board
Category:
Sustainable Production
Keywords:
(none assigned)
Parent Project:
Developing a Comprehensive Management Program for Foliar Diseases of Soybean (Year 1 of 2262)
Lead Principal Investigator:
Ahmad Fakhoury, Southern Illinois University
Co-Principal Investigators:
Edward Sikora, Auburn University
Daren Mueller, Iowa State University
Blair Buckley, Louisiana State University
Clayton Hollier, Louisiana State University
Tom W Allen, Mississippi State University
Maria Tomaso-Peterson, Mississippi State University
Burton Bluhm, University of Arkansas
Travis Faske, University of Arkansas
John Rupe, University of Arkansas
Carl Bradley, University of Kentucky
Heather Kelly, University of Tennessee-Institute of Agriculture
Rouf Mian, USDA/ARS-Ohio State University
Leslie Domier, USDA/ARS-University of Illinois
Glen Hartman, USDA/ARS-University of Illinois
Alemu Mengistu, USDA/ARS-West Tennessee Experiment Station
+14 More
Project Code:
1520-532-5662
Contributing Organization (Checkoff):
United Soybean Board
(n/a)
Institution Funded:
Southern Illinois University
(n/a)
Brief Project Summary:

Unique Keywords:
#foliar diseases, cercospora leaf blight, frogeye leaf spot, soybean vein necrosis virus, #foliar fungicides, phomopsis seed decay, septoria brown spot, fungicide resistance, , #soybean diseases
Information And Results
Final Project Results

Updated October 30, 2017:
1. Genome sequencing work has further defined the pathogenic organisms causing Cercospora sojina (Frogeye) and Cercospora leaf blight (CLB). CLB has been found to be caused by a number of species with C. flagellaris as the main one in the U.S. Ninety six SSR markers have been developed for CLB to characterize and enumerate U.S. isolates. Focus is on those that produce a minimum amount of cercosporin toxin, as is thought to be the cause behind leaf bronzing. For C. sojina or Frogeye Leaf Spot, the re-sequencing of select isolates to verify the SNP markers will now help identify distinct loci that can be used to classify isolates into distinct races (somewhat akin to Phytophthora races).
2. Carl Bradley of Illinois has found fungicide resistance in isolates of CLB. Most of these isolates were from Louisiana where fungicides are used heavily to control CLB. Resistance was demonstrated for benzimidazole and strobiluron fungicides.
3. In TN, field screening was conducted on 120 lines with potential but varying levels of resistance to Frogeye leaf spot (FLS) including those with potentially having resistance beyond the current source of resistance (Rcs3 gene). Thus far, seven lines showed excellent and broad resistance to FLS.
4. A field test was conducted in 2015 to determine the yield loss curve for soybean vein necrosis virus and to separate out the yield effect of thrips (that transmits the virus). Results are forthcoming.

Progress has been made to develop novel sources of resistance to Frogeye Leaf Spot. For the first time, resistance sources to Cercospora Leaf Blight have been initially identifed. New means to screen for these two major diseases are under development to enhance the breeding for resistance. Methods to detect fungicide resistance of Frogeye strains to foliar fungicides has been determined, that in turn, has led to establishment of a geographic map for incidence of fungicide resistance. Foliar fungicides are screened annually for efficacy against all major foliar diseases and published widely.

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.