WASHINGTON, D.C. – A group of Midwest plant pathologists has been awarded a $150,000 Rapid Outcomes for Agricultural Research (ROAR) grant by the Foundation for Food & Agricultural Research (FFAR) to study and mitigate tar spot on corn.  

“It’s especially difficult to develop solutions for tar spot when the underlying fungus can’t be grown in a lab,” said Sally Rockey, FFAR executive director. “The researchers will study tar spot in the field to generate the knowledge needed to help farmers make timely and economical decisions to prevent the disease.”

The research team is comprised of plant pathologists from the University of Illinois, Iowa State University, Purdue University, Michigan State University, The Ohio State University, and the University of Wisconsin-Madison.

The National Corn Growers Assoc., Corteva Agriscience, Wyffels Hybrids, the Illinois Corn Growers Assoc., and Purdue University matched the ROAR grant for a total investment of $300,000.

First detected in the U.S. in 2015, tar spot has quickly spread through the Corn Belt. In 2020, tar spot was confirmed in Ontario, Canada and Pennsylvania. Scientists predict that tar spot could soon reach as far west as parts of North Dakota and east to New York, further devastating yields. 

Corn tar spot often appears as raised black spots on the upper and lower parts of the leaves and can have significant impact on yield. 

The disease causes significant losses for farmers’ livelihoods. For example, a one percent reduction in total domestic corn production could cost American farmers an estimated $231 billion in lost revenue, according to FFAR.

The FFAR said efforts to combat the disease have been hampered by the difficulty of growing Phyllachora maydis in a laboratory – an essential step for developing a remedy. In addition, little is known about the biology of the fungus, which is required to develop effective management practices. 

Currently, the team of university pathologists is developing tools and techniques that can help study this pathosystem in basic and applied settings and develop tools to combat the disease. 

“This information will provide farmers with better hybrid choices, improve understanding of management practices for suppressing tar spot, and help inform decisions about the need to apply fungicides, which can better protect crops from corn tar spot if the application is timed correctly,” a FFAR statement read.

Moreover, the multi-state effort is focused on developing research tools and information to help growers with tar spot management, the FFAR said. 

“The team’s research is mapping where the fungus is present, assessing the potential origins of the fungus and potential alternate hosts, understanding resistance in corn germplasm, assessing tar spot management options such as resistant hybrids and fungicides and developing outreach and extension materials for corn farmers,” the statement said. 

The researchers are also building forecasting models to help producers make timely fungicide decisions using a free smartphone application. 

By working with corn farmers to collect information, the FFAR said this research will provide immediate benefits for producers.

“FFAR’s ROAR program is a nice platform for enabling researchers to generate preliminary data on rapidly emerging pathogens and pests,” said Nathan Kleczewski, University of Illinois, Champaign-Urbana extension field crop plant pathologist, and the study’s primary investigator.

“In this case, FFAR’s ROAR program enabled several researchers the ability to generate preliminary data that not only are important for producers,” he added. “But also can be leveraged to support future research projects that will help combat tar spot not only in the U.S., but other countries where this disease is problematic.”

Martin Chilvers, a Michigan State University field crops pathologist, has been investigating how to manage and mitigate the fungal disease native to Central and Latin America since it first started appearing in the state around 2016.  

“Essentially, all around the lower half of Lake Michigan, so the west and southern part of Michigan, southern Wisconsin, northern Illinois, northern Indiana, were severely affected with this disease,” he said. “In 2018, some fields saw losses of up to about 50 bushels per acre, which is really significant in terms of corn production and affecting people’s livelihood.”

Chilvers said he’s hopeful his research on corn tar spot, which is partially funded by FFAR, will result in better management, profitability and sustainability for farmers and producers.

“With increasing global populations, we’re going to be pushed harder to produce more on the same amount of land,” he said. “Diseases are a large part of yield loss, so that’s just sort of a passion of mine – trying to assist with food security and food production.”