Since first identified in Indiana in 2015, tar spot has garnered more and more attention as its spread west into the corn belt.
Damon Smith, Extension Field Crops Pathologist, Department of Plant Pathology, University of Wisconsin-Madison, is using the framework of the previously released Sporecaster app, but he’s working to customize it with new datasets specific to Tar Spot.
The Tarspotter app is currently being tested by Extension and industry personnel. While it’s not publicly available, Smith says he will be updating his outlook and risk assessment for Tar Spot via the app’s capabilities.
Data powering the Tarspotter app includes modifications specific to corn, data from the Arlington Agricultural Research Station in Arlington, WI and from a single location in Michigan, and data from several fungicide trials.
Smith says Tar Spot could be a significant disease in 2019 if the weather stays wet and cool.
However, he says farmers need to keep the pest triangle in mind, and at this time he’s not recommending any fungicide applications to control Tar Spot. Iowa State University Extension is also not recommending applications at this time to control any threat of Tar Spot.
If/when fungicide applications are necessary and justified, here’s a link to the fungicide trial report from University of Wisconsin.
Here is previous coverage from AgPro on Tar Spot
New Fungicide Labeled for Tar Spot Control