By Linda Geist
Good scouting is the best way to identify tar spot in corn, says University of Missouri Extension state plant pathologist Mandy Bish.
Tar spot was confirmed in June of 2023 and 2024 in Missouri, which is earlier than in previous years, when the disease showed up in August or September. This earlier appearance is likely to continue because Missouri’s spring air temperatures are favorable for the disease, says Bish. However, the disease typically slows significantly in July as air temperatures rise.
Tar spot gains ground in Missouri cornfields