Good Morning John, 

Thank you for contacting the U of M Extension Service.

You indicated you applied a fungicide treatment. How did you determine it is a fungus? 

You might inspect the soil below the spots to see if this issue is grubs: https://extension.umn.edu/news/white-grub-control-lawns

Here is a link to the lawn care calendar: https://extension.umn.edu/planting-and-growing-guides/lawn-care-calendar

You could also send a sample to the Plant Disease Clinic to verify the probem: https://pdc.umn.edu/

I would pull up the sod in an area where the grass has died and see what is happening to the roots and the soil. Might inspect for grub damage.  I would also closely examine the dying grass blades to see what other issues might be apparent. 

Is the soil compacted or is there any other issues that may have caused the probem? 

I will also mention the newer alternatives to lawn turf grass. Turf grass is a sterile environment for nature. Various chemicals applied to the turf grass makes it additionally toxic to our pollinators. Our insects and pollinators are becoming extinct at an amazing rate.

Please click on the following links:

https://extension.umn.edu/lawns-and-landscapes/planting-and-maintaining-fine-fescue-lawn

https://extension.umn.edu/landscape-design/planting-and-maintaining-bee-lawn

Good Luck!

Good Morning John, 

No, I had no idea. But the Plant Disease Clinic refers you to the Turf Grass Diagnostic Lab in Wisconsin. The fee to submit a sample is $ 20. 

I read through the requirements to submit a sample. You could send a sample next Monday and possibly have an answer by the end of the week. 

Since you have researched the issue, inspected the grass and sod, this might be a good idea. 

If you do this and receive a response, I'd be interested in hearing the results. 

Good Luck!