Where do you live?

What kind of grass do you have?

What do you mean by regular watering? How often and how long do you water?

Thanks for your response,

I live in southern PA. The grass is a mixture of perennial ryegrass and kentucky bluegrass, but mostly perennial ryegrass. I water each section of the lawn in the evening, 3 times every 2 weeks for about 40 minutes each time using a Rainbird impact sprinkler.

Anybody have any ideas?

How long did it take for your grass to recover from this fungus / did you take any steps to expedite recovery?

Ours took about a year, but we have Zoysia, a warm season grass. We used a commercial fungus treatment and the next summer plain cornmeal broadcast on the bare areas. Zoysia spreads by runners and gradually filled in. Cornmeal will also keep seeds from sprouting, I believe. You need to google for treatment in your area and type of grass. What worked here, might not help you. Start watering in the morning only to begin. That will help for sure. With cool season grasses you should be able to overseed the bare areas. I like the university web sites for information.

Thanks for the info, I've started raking up the thatch and stopped watering. I'm having a professional come to aerate / overseed soon because I read the fungus happens due to a lack of nitrogen (which aeration will fix) so I'll ask him what he thinks. Thanks for sharing your experiences!

How does aeration fix nitrogen?

How does aeration fix nitrogen?

It allows the nitrogen in the air to get into the soil through the holes.

Am I the only one who doesn't understand the watering? Does each section get 120 minutes on one day, every two weeks?

Am I the only one who doesn't understand the watering? Does each section get 120 minutes on one day, every two weeks?

Each section gets 30-40 minutes on three different occasions in two weeks. This way it's a bit staggered. I could've said each section gets 30-40 minutes 1.5 times every week but that wouldn't make sense.

Definitely looks like a fungal disease or diseases. (Dollar Spot, Brown Patch, Summer Patch, etc.) Cooler weather is coming and that will be the best remedy. If you are really anxious, you could apply chemical fungicide. If you are not familiar, there are some you can find at Home Depot / Lowes such as Immunox (Myclobutanil), Bayer Fungus Control for Lawn (Propiconazole), etc. These 2 supposed to have relatively low toxicity to earthworms.

As many have preached, and I have learned the hard way, prevention is the key. Once the diseases has exploded like this, it's a tough battle.

Chemical fungicides are nasty stuff. Use it only when needed. There are biofungicides but they are more effective as a preventive.

Having had a bad Summer Patch outbreak this year, I will be doing 2 apps of Heritage/Companion combo early in the Spring, then alternate apps of Companion and Serenade all season long.

Regarding watering, do 1" once per week in the morning, never in the evening when temperature/humidity is high.

Jeff508: Cooler weather is coming and that will be the best remedy.

^

So it will disappear in the fall when cool weather hits but it'll come back in the spring?

Cooler weather will stop the progression of the disease but dead grass won't come back. I have 100% KBG and they spread fast once conditions improve. Bunch type grass don't spread fast to fill in dead spots.

You should try to keep the grass alive, even if they are diseased so they can come back with cooler temperature. What you need to do depends on what disease you are battling. I had Summer Patch which is a root disease. So I watered it lightly every day or two. If you are dealing with a foliar disease, this type of watering probably aggravates the problem.

Summer patch will most certainly come back next year but if you have a foliar disease, it may not.

Everyone's situation is different so no one can tell you on the internet what you need to do. One thing I learned over the years is there is no easy way to learn about this stuff, You need to spend hours and hours reading, examining, experimenting, etc. You can get some basic knowledge here, but your soil, your grass, your weather is different from mine.

DcHall swears by cornmeal but some others say it does nothing. It may work for you, it may not. I did 2 apps of Heritage/Companion combo in August and I believe it stopped Summer Patch. Within a week, sickly green color was changing to "healthy" green. 2-3 weeks later, dead spots were filling in.

When I was raking up the thatch the lower part of the blade that connects to the root had a black, dark brown-red color. I still haven't been able to pin down what the exact disease is but I think this means it's a root disease?