Nebraska Extension Blog by Jenny Brhel
Received several calls about tar spot yesterday and today. As of right now, it’s been confirmed at LOW incidence in Saunders, Pierce, and Clay Counties on 6/16/25 and in Polk and Seward Counties on 6/17/25.
I really appreciate Craig Anderson and Mike Byers bringing me leaf samples to confirm. I also appreciate those who were calling to hear of any confirmations from leaf samples.
There’s a lot of fear surrounding this disease, and still some unknowns. We haven’t seen tar spot in Nebraska this early. It would be helpful if consultants/agronomists would confirm samples to Dr. Tamra Jackson-Ziems, the UNL Plant and Pest Diagnostic Lab, or a local Extension Educator so that we have the most accurate information to provide. Tamra will update the tar spot map at: https://cropprotectionnetwork.org/maps/tar-spot-of-corn.
We are NOT recommending fungicide application in fields where tar spot is confirmed in these early vegetative stages.
I share why we’re not recommending fungicide including the data that Purdue University found in 7 years of dealing with early tar spot in corn in this blog post: https://jenreesources.com/2025/06/17/tar-spot-of-early-corn-update/
Please reach out with questions. Thanks!-Jenny
The images below are courtesy of Dr. Tamra Jackson-Ziems of UNL and Dr. Darcy Telenko of Purdue University.
