Tarspotter for the Find
Mar 26, 2025
The fungus that was first seen in Federated’s geography in 2019 is the talk of the town in 2025, even as everyone is still learning about it – tar spot.
“The later the infection comes in, the less chance of significant yield reduction,” said Craig Loen, Federated ag sales rep in Osceola. But on the flip side, if infection from this residue-borne fungus takes off earlier in the season, yield loss can be significant. (For example, an isolated small area in SE Minnesota saw yield losses of over 50 bu./ac.)
A new app called Tarspotter from UW-Madison offers a way to track tar spot when it appears in your fields. “It helps give you information on the spreading of tar spot via GPS coordinates where it has been found,” said Loen. And with that information, you and your Federated Agronomist can make better disease management decisions. The app is available for Apple and Android devices.
Tar spot flourishes when the disease triangle is complete – when the three “sides” come together: the corn plant (host), the pathogen (fungus), the right environment (cool and moist). Tar spot moves with the wind, and moist conditions fuel its growth, so it’s critical to be extra aware of environmental conditions.
With the Tarspotter app and consistent scouting during the critical stages of V8 to R4, you can keep tabs on tar spot development and determine when and if treatment is needed. Federated recommends Miravis® Neo, applied at VT. Link to this week’s article.
Tarspotter is a free app available from the University of Wisconsin. It is easy to set up and offers step-by-step instructions on the Help and Information tab.
Contact your local Federated Agronomist with questions and concerns about tar spot. (See this article for additional info on tar spot.)
“The later the infection comes in, the less chance of significant yield reduction,” said Craig Loen, Federated ag sales rep in Osceola. But on the flip side, if infection from this residue-borne fungus takes off earlier in the season, yield loss can be significant. (For example, an isolated small area in SE Minnesota saw yield losses of over 50 bu./ac.)
A new app called Tarspotter from UW-Madison offers a way to track tar spot when it appears in your fields. “It helps give you information on the spreading of tar spot via GPS coordinates where it has been found,” said Loen. And with that information, you and your Federated Agronomist can make better disease management decisions. The app is available for Apple and Android devices.
Tar spot flourishes when the disease triangle is complete – when the three “sides” come together: the corn plant (host), the pathogen (fungus), the right environment (cool and moist). Tar spot moves with the wind, and moist conditions fuel its growth, so it’s critical to be extra aware of environmental conditions.
With the Tarspotter app and consistent scouting during the critical stages of V8 to R4, you can keep tabs on tar spot development and determine when and if treatment is needed. Federated recommends Miravis® Neo, applied at VT. Link to this week’s article.
Tarspotter is a free app available from the University of Wisconsin. It is easy to set up and offers step-by-step instructions on the Help and Information tab.
Contact your local Federated Agronomist with questions and concerns about tar spot. (See this article for additional info on tar spot.)