I'm not too familiar with your type of grass and I am not an expert either. But I have been dealing with fungus in my St. Augustine, Zone 9 and I can say, that does look fungal in nature. Not sure with COVID right now, but we have nurseries that diagnose these problems under a microscope. You need to take in a patch of dieased turf mixed with healthy grass for an accurate diagnosis. It looks like that area could benefit with aeration and compost in the fall.

I hesitated to reply to this because it is not a southern lawn. It would appear to be a fungal disease caused by too frequent watering.

What is your automatic watering schedule? How often and for how long do you water?

Missed this with all the Windows 10 drama I've been having. Yep, it does look fungal to me as well; dollar spot or brown patch, hard to say as it's early in the cycle.

Zone tells us little; what's the city/state? Or state, at least? Right now, the east is well-suited for explosive fungal disease and, with overwatering at the wrong times, serious problems can become fatal ones in a day or two.

Or, in other areas, this might be controlled just by watering changes.

Thanks for the feedback.

With regards to location the closest major city is St. Louis, MO.

I am watering 2x week 1/2" each (bump it up to 3x when temps stay in the high 90s for long periods), but we have gotten a decent amount of rain recently so haven't needed to add the third.

The system is set up with a rain gauge so it stops if it has rained a lot recently. However, as stated above that part of the lawn is known to have draining issues and has standing water at times if we get a lot of rain.

At this point to mitigate the damage should I use a combination of propicanizole and azoxystrobin fungicides?

So you're not in the worst of the heat wave like we're getting and, while rather a lot of water, it's merely too much rather than hyper-extreme.

I think I'd go with DiseaseEx right now (Azoxystrobin) and cycle in two weeks if the problem continues (one shot might take that out. Might). In two weeks, use something different.

As this summer cycles down, try setting the watering to every 4 days instead of twice a week. It'll discourage the fungal cycle. And always water early enough in the day that the lawn is dry by nightfall. Where water stands...well, that's harder, of course. Avoid if possible, but sometimes it's not.

Optimally, you'll deliver 1" of water a week, however that's dropped.

See if you can then stretch out to every 5 days. The lawn may wilt a little bit at mid-day. If it recovers by morning, that's fine--it means the roots caught up. Right now, at 94 to 98 degrees, mine's doing that daily. And it hasn't rained in a week and I don't irrigate.

You may not get past that next summer, but see how far it stretches. Some lawns really stretch. Others, not so much. Almost all northern lawns will go seven days once trained. Some, far longer.

Thank you.

RE: watering, since I have drainage issues I have been hesitant to cut down to 1x/week or spread out watering because I would need to put down more water each time. Right now the cycle starts at 5 a.m. and is dry by the end of the day. My fear has been that the larger amounts will not drain well enough for it to dry out. However, my plan hasn't exactly worked out either...

Understood. Have you tried researching spraying shampoo or liquid soap on the lawn? Yeah, it sounds odd, but really does help. If you can't find data and are interested, I'll type it out again and save the text this time. It does help with drainage in bad areas.

This year, it's hard to help too much, the weather just hasn't been terribly conducive to a good lawn year (or garden year for that matter). If you can back off that extra day, great. But if not...well, don't worry about it this summer.