SITUTAION AND RATIONALE
Soybean sudden death syndrome (SDS) is a devastating emerging disease with an estimated impact of more than $330 million dollars in the U.S. SDS quickly spread from first reports in Arkansas in the 1970’s to nearly all soybean-producing states. In North America, soybean SDS is caused by the soil borne fungus Fusarium virguliforme, however in South America an additional three closely related species have also been implicated: F. tucumaniae, F. brasiliense, and F. crassistipitatum. The pathogen infects soybean roots and produces toxins that cause foliar symptoms. In addition, yield loss may occur through diseased roots despite the lack of typical foliar SDS symptoms.

Soybean SDS continues to be a significant threat and limit to soybean production in Michigan. In 2016, we confirmed an additional county to be infested. Between soybean crops the SDS causing fungus is capable of surviving in the soil and on crop debris such as corn. As such this disease is likely to become progressively worse with time as the amount of SDS fungal inoculum continues to build in the soil.

In addition to the widely recognized F. virguliforme, we have found F. brasiliense in Michigan. This is the first report of this species in the U.S. So we are actively working to better understand its distribution and management.

Soybean cyst nematode (SCN) is also a primary threat to soybean production in the U.S., including Michigan. Often SCN will exacerbate plant stress and act synergistically with other plant pathogens, such as SDS.

1. Develop SDS risk assessment tool to predict SDS and yield loss given a soil sample analogous to SCN testing.

2. Assess new seed treatments for SDS and SCN management
a. At our Decatur location with heavy SDS and SCN pressure we will screen seed and in-furrow treatments for disease management.
b. Screen seed treatments in the lab and greenhouse for efficacy against F. virguliforme, F. brasiliense and closely related species
c. Determine F. virguliforme fungicide sensitivity to fluopyram and pydiflumetofen, to check the populations for any resistance to these fungicides.

3. Develop methods to rapidly phenotype soybean germplasm for resistance to SDS through real-time quantitative PCR and aerial imaging and image analysis
a. Utilize our real-time quantitative PCR assay to identify root rot resistance QTLs
b. Work with the MSU RS&GIS team and colleagues to capture aerial images and analyze image files to improve phenotyping of breeding material and assessment of seed treatments

4. Assist soybean breeders in evaluating breeding material
a. Produce SDS inoculum for on campus screening of germplasm
b. Coordinate screening of germplasm on campus in inoculated trials
c. Facilitate and coordinate screening of germplasm at Decatur
d. Train Dr. Wang’s lab in rating of SDS plots and use of our qPCR technique to evaluate for SDS root rot resistance.

5. Educate growers and CCA’s on biology and management of SDS

6. Determine the pathogenicity and virulence of Fusarium brasiliense isolates from Michigan.

7. Train a MSc or PhD level graduate student

Research results will be distributed through field days, and extension meetings. A multi-state extension bulletin will be produced and made available through the Crop Protection Network (www.cropprotectionnetwork.org) and articles will be created for Michigan Soybean News and MSUE News for Ag. YouTube videos will also be created to report results, and social media such as Twitter and Facebook will be used to relay take-home messages to the Michigan agricultural community.