Tar spot has taken hold across the Great Lakes this season with its strongest presence in Michigan and Indiana.
Kristin Poley with the Corn Marketing Program of Michigan tells Brownfield hot, wet conditions in July and August has the disease spreading like crazy.
“Tar spot is everywhere this year,” she says. “We haven’t quite seen it at this distribution this early in the season ever.”
She says if growers aren’t treating, they could see at least 50-bushel yield losses.
“The big concern this year is how many sprays can you do and still remain profitable,” she explains. “Now we are getting up to R4, R5, and is it going to be profitable to apply again? There is good data to say yes, if you do it now you could be profitable but always make sure you’re looking at your breakeven points.”
Poley says infected cornfields will dry down much earlier and are prone to lodging so growers need to be paying close attention to fields that need an early harvest.