Did you check for webworm?

Did you probe for grubs?

Easy checks IMO. Can rule them in or out easily.

 

Looks like dollar spot and brown patch at the same time but tough to do an ID with pictures

DO NOT water at night you are just inviting fungal disease, fungi love warm moist nights only water in early morning, the site should be as dry as possible when the sun goes down

looks like a spider to me, not web worm

 

The spider webs are unrelated to the fungus, have the spiders myself and you can see the webs best early in the morning when the dew is still on them and if you sneak up on one you will see a red spider right in the center; nothing to worry about.

The fungus now, another story. Not sure which it is, take all, Brown patch, blight, but it's clear its done gone too far and the area's are dead. Best advice, reseed in the fall and now that you have a fungus it will lay dormant in the soil till the conditions are right next year. Alternate between fungicides to control it before it starts. Heritage, Eagle and Cleary's 3666 every month.

ICT Bill is right, avoid watering in the evening.

 

Would you think the fungus is in remission, or dormant at this point? Or is it still growing and going to kill more of the lawn? Should it be treated right away, if so could you recommend any particular fungicides?

Please let me know.

-Chris

 

IMO it certainly does not look like any sort of insect damage.

Not certain it's a disease problem either. You mentioned it seems to be a problem on some sort of bentgrass exposed to sunlight. That's where picture #2 comes in. Looks like possible rough bluegrass (poa trivialis). It goes dormant during summer heat and recovers during the fall. Rough bluegrass looks nearly identical to some of the fine fescues, but one way to tell........it pulls up very easily (like a carpet) cuz it has very shallow roots.

Final note: the Kentucky bluegrass looks fairly healthy, so I'm thinking you either have fine fescue mixed in that is going dormant, or else it's poa trivialis.

Bottom line: fungicides would be a waste of money this late in the season. Core aeration is always a good thing to do in the fall. But I think you have another grass type in the mix with this Kentucky bluegrass lawn. Can't tell from the pics, but it is not bentgrass.

Best guess is rough bluegrass. My 2 cents.

p.s. We received 11 inches of rain during the past 3 days. Des Moines, IA (not good)

 

I forgot to mention a relatively new site that offers current info regarding turf probs.

http://www.iaturf.blogspot.com