Cool season lawns can go dormant over the hot dry summer, but if too dry or dormant too long, you will see a lot of die-back. Irrigate and fertilize to promote new growth from the crowns of the plants. Lawns that have gone dormant should green up again in one to two weeks once you start irrigating again. Additionally, the crowns of the plants will still still be alive if the turf is dormant but alive.  Inspect the base of the grass. If the small growing points still have some green, they should be able to eventually recover.  If plants are completely dead, the lawn area should be reseeded in the fall.

More information can be found here:

https://www.extension.iastate.edu/news/drought-damaged-lawns-need-help

Information on reseeding (if needed) can be found here: https://www.extension.iastate.edu/news/yard-and-garden-establishing-lawn-seed

Also here: https://store.extension.iastate.edu/product/4376

Finally, below are several links to our nearby neighbors in Indiana about this topic.  It provides some additional information and advice to evaluate and manage drought stressed or damaged lawns.

https://turf.purdue.edu/facts-and-advice-on-turf-survival-in-drought/

http://purdueturftips.blogspot.com/2012/06/my-lawn-is-brown-and-crunchy-is-it-dead.html

https://www.purdue.edu/newsroom/releases/2012/Q3/purdue-extension-has-advice-for-repairing-drought-damaged-lawns.html

Happy gardening!

--Aaron

Thank you.  If you have not already found this resource on fall armyworms, here it is for your convenience. https://hortnews.extension.iastate.edu/2021/09/fall-armyworms-surprise-2021

Best of luck and happy gardening!

--Aaron