José E. Solórzano
Graduate Research Assistant
University of Minnesota
St Paul, Minnesota, United States
Milton Drott
United States Department of Agriculture-Agricultural Research Service, Cereal Disease Laboratory
St. Paul, Minnesota, United States
Matt Moscou
United States Department of Agriculture-Agricultural Research Service, Cereal Disease Laboratory
St. Paul, Minnesota, United States
Aarav Subbaiah
University of Minnesota
St. Paul, Minnesota, United States
Crystal Floyd
University of Minnesota
Saint Paul, Minnesota, United States
Nathan Kleczewski
Syngenta Biologicals
Kernersville, North Carolina, United States
Diane E. Plewa, MS (she/her/hers)
Extension Specialist
Univ of Illinois Extension
Urbana, Illinois, United States
Teddy Garcia-Aroca, PhD
Assistant Professor
Department of Plant Pathology, University of Nebraska-Lincoln
Lincoln, NE, USA
Tamra Jackson-Ziems, n/a
Primary Investigator
University of Nebraska - Lincoln
Lincoln, Nebraska, United States
Morgan Goodnight, n/a
PhD. Graduate Student
Purdue University
West Lafayette, Indiana, United States
Mandy Bish, n/a
Assistant Professor
University of Missouri
Columbia, Missouri, United States
José F. González-Acuña (he/him/his)
Iowa State University
Ames, IA, USA
Dean Malvick
Professor
University of Minnesota
St Paul, Minnesota, United States
Tar spot of corn (Zea mays subsp. mays), caused by the fungus Phyllachora maydis, is an increasing threat to US corn production. The disease has also been known in other parts of the Americas for over a century. P. maydis was the only Phyllachora species reported to infect corn until a recent study suggested that various Phyllachora spp. may be infective and possess a broader host range. The goal of this study was to determine the host range and diversity of Phyllachora spp. associated with corn. We conducted molecular analyses to identify alternative hosts, identify Phyllachora spp. associated with corn, and determine if they infect grasses. We also conducted inoculations on grasses from the US and corn relatives native to Mexico and Central America in field and controlled environments. Preliminary results from maximum likelihood analysis of Phyllachora isolates collected from different plant species in agricultural and nonagricultural areas in the Midwest suggest that only P. maydis was present in corn and the Phyllachora spp. isolated from grasses were not detected in corn. Inoculation studies identified that Z. diploperennis, Z. perennis, Z. luxurians, Z. nicaraguensis, Z. mays subsp. mexicana, Z. mays subsp. parviglumis and Z. mays subsp. huehuetenangensis are hosts of P. maydis. This is the first report of P. maydis having a host range beyond corn, suggesting that alternative hosts may play a role in the disease cycle of tar spot of corn. These results have implications for the ecology and evolution of P. maydis, and management of tar spot of corn.