Hi Eric,

Brown spots in lawns can be caused by a lot of different things, but most often it's due to an irrigation issue. To help us better diagnose what might be happening to your turf, we have a few follow-up questions:

- When was the damage initially noticed, and has this happened before?
- What is your turf watering schedule? Have you noticed any pooling?
- Do you fertilize and/or aerate your lawn? How often?
- How often do you mow your lawn? How tall is the grass blade after mowing?
- Are the brown spots primarily in the more sun-exposed areas of your lawn?

In the meantime, here is a fact sheet on basic lawn care that has a lot of valuable information on the best ways to keep your turf looking green throughout the season: Lawn Care 

Additionally, it might be useful to conduct an irrigation audit to ensure that all areas of your turf are being adequately watered. Check out this resource on how to conduct an irrigation audit.

Another follow-up question:

- Do you know what grass type/species you have?

It's possible that you might have mixed species in your lawn, and if one of those species is a roughstalk bluegrass, then the brown spots are normal (though not desirable) as roughstalk bluegrass is dormant this time of year. Check out this PlantTalk resource on roughstalk bluegrass: Roughstalk bluegrass in household lawns

With regards to grubs, this is also a possibility:

- Have you seen any grubs in your lawn?
- When you pull at the damaged turf, does it come away from the ground easily or does it feel like the roots are intact?

If you see grubs or if the turf pulls out of the ground with no resistance, then yes, the brown spots might be due to grub activity. Here is one more additional fact sheet on grubs in turf: Billbugs and White Grubs: Control in Home Lawns

We look forward to hearing back from you, and please let us know if you have any additional questions!
Caitlin W. and Jessie A.