Its impossible to tell from the photo what is going on. There are several options:

The fertilizer company spilled or over applied and it burned the grass there

or

Grubs could be a problem, Best way to tell is if you tug or dig up (with a spade) along the border of the dried and alive grass, it comes up easy and you spot them. Best control is a healthy vigorous lawn mown high and irrigated.   https://extension.entm.purdue.edu/publications/E-271/E-271.html

or 

This is a symptom of drought. Sioux Falls has only had 2 days of decent rain between now and the latter half of May. It also appears that this lawn is mowed fairly short and gets full sunshine through the day. If true, that's not a good environment for grass and early dormancy and/or damage may result. Set the mower at its highest setting, and mow infrequently on mild/cloudy days and then make sure it gets moisture either rain or irrigation right after.   

https://extension.sdstate.edu/dealing-drought-stressed-lawns

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