Cases of tar spot in corn have been reported over recent weeks in 12 Iowa counties. Iowa State University Extension and Outreach plant pathologists have been able to confirm the presence of tar spot in four counties via the Iowa State University Plant and Insect Diagnostic Clinic. Agronomists and collaborators have confirmed the remaining cases throughout the state. The current counties with confirmed tar spot presence include: Jones, Jackson, Johnson, Muscatine, Fayette, Clayton, Black Hawk, Buchanan, Delaware, Dubuque, Clinton, Scott, Grundy and Chickasaw counties.