Growers across rural America are reporting unprecedented tar spot infestation this harvest season. When conditions are right, the disease can cause significant yield loss in susceptible corn hybrids. Tar Spot was first detected in the U.S. in 2015 in Illinois and Indiana, and it’s quickly spread through the Corn Belt and caused significant losses.
Efforts to combat the disease has been hindered by the difficulty of growing the fungus that causes tar spot in a lab. The National Corn Growers Association has two Action Teams, both ready with support from state checkoff dollars and focused on aiding the fight against Tar Spot.
2021 growers can monitor this year’s reported incidences of tar spot spread on the corn.ipmpipe.org website. If growers see Tar Spot in their fields, they’re encouraged to use the reporting form on the website.
The Corn Protection Network’s publication recommends several best management practices, including managing residue of the affected crop to reduce inoculum from overwintering; rotating to other crops to reduce the primary tar spot inoculum; avoiding highly susceptible hybrids, as well as investigating effective fungicides.