First Wisconsin Tar Spot Case Confirmed for 2026. Natalina Sents Bausch is the Digital Director for Successful Farming and Agriculture.com. Natalina joined the Successful Farming team in 2017 to cover new farm machinery and news coverage for Agriculture.com. The season’s first case of tar spot in Wisconsin has been confirmed in Lafayette County, according to the latest maps published by the Crop Protection Network. Sixty-three of the state’s 72 counties have a history of tar spot since it was first detected in Wisconsin in the fall of 2016. First 2026 Illinois Tar Spot Case Confirmed. First 2026 Tar Spot Cases Confirmed in 3 Indiana Counties. First 2026 Tar Spot Cases Confirmed in 5 Kansas Counties. First 2026 Missouri Tar Spot Case Confirmed. First 2026 Cases of Tar Spot Confirmed in 8 Nebraska Counties. First 2026 Cases of Tar Spot Confirmed in 3 Iowa Counties.