Tar spot continued its westward spread in 2026, with new confirmations in southwest Nebraska bringing the statewide total to more than 70 counties.
The Crop Protection Network’s Tar Spot Distribution Map shows positive reports of tar spot through much of Nebraska east of the panhandle as of Oct. 30.
Tar spot produces small, black fungal structures on corn leaves that cannot be rubbed off. Cool, wet conditions favor disease development, particularly in irrigated fields.
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This article was originally published on Nebraska Extension’s CropWatch website, written by Tamra Jackson-Ziems - Extension Plant Pathologist, Talon Mues - Extension Educator, Kyle Broderick - Extension Educator and Coordinator of the UNL Plant and Pest Diagnostic Clinic, Samantha Daniel - Extension Educator, and Ruby Collins - Extension Educator.





