Looks like the first, of what will be many, Dollar Spots.
If it is Dollar Spot, you are likely to get a wide and conflicting group of suggestions.

The greenhouse near me that I trust suggests using a brand name fungicide early in the disease stage to help control it. There are pictures on the bag that show Dollar Spot and Brown Patch; application rates are different.

Capt Tom

The fuzzy mycelium does look like dollar spot. A conclusive diagnosis can be made if you can find grass blades that are green at the top and bottom, with a brown stripe through the middle. Look at the attached link.

In any case, I concur with Captain Tom - get a fungicide out there today. Then do it again according to the label directions, I think it will say a week or two later.

Here is a link that might be useful: Purdue Dollar Spot Info

Show Green - I spotted the exact same disease in my backyard a few days ago and have been struggling to figure out exactly what it is. Meanwhile it has seemed to spread pretty quickly. I would be interested to know if you found a helpful product to treat this, or what you're planning to do. The only product I've seen on the web is Scott's Fungus Control. I have no idea if this is a good product, and woudl be interested if you have discovered anythign else, or if anyone could recommend something.

From what I've read, it may require several fungus treatment applications and then perhaps aeration at an appropriate time followed by fertilizer to increase Nitrogen levels in the soil. Does that sound about right?

Ckarsman

Multiple applications (every two/three weeks) is what I have been told. As to the nitrogen: there are those who say it was the cause of the the fungus and those who believe a lack of nitrogen caused it.

I am not sure which is correct, so I am treating the front lawn with fungus treatment alone, and the back yard with fungus stuff and a light dusting of a 29-0-0 fertilizer.

We'll see.

Capt Tom

Hi,

Thanks for all the feed back on this.

Ckarsman
I think Capt Tom and darius_07 are right that its Dollar Spot.

I put down another Scott's Fungus Control but I also put it down 4 weeks ago be for I got this fungus. Its very hi humidity here right now like 80%. So I guess we will see how it goes now.

Thanks for the messages. I investigated as Darius said and confirmed Dollar Spot as well. Interestingly, I fertilized a few weeks ago (maybe 3 or 4) with Milogranite. The yard was starting to look amazing. I probably should have dethatched prior to that, but didn't have time.

Anyway, I went to Depot last night. They carry the Scotts Fungus product (which I bought) and another one by Spectracide (pellets, not liquid). I read both of them, and they contain different active ingredients. The Scott's contains - Dimethyl [(1,2-phenylene) bis iminocarbonothioyl)] bis [carbamate] (Thiophanate-methyl). I didn't write down what the Spectracide pellets contained, but it definitely was different than what's in Scotts. Any recommendations from anyone would be greatly appreciated. Thanks.

On another note, I believe my lawn needs to be dethatched. We just moved in (Pittsburgh) in December, and the other owners hadn't done it for a couple years. Can you do this in the mid/late summer? If not, when? THansk.

I used a Spectracide liquid product called Immunox. See the attached link. The active ingredient is myclobutanyl. It worked for my dollar spot, and also for powdery mildew, but I suspect that any broad-spectrum fungicide will work.

One thing to keep in mind: If you have to treat more than a couple of times, don't keep using the same product. Use products with different active ingredients. Otherwise you risk building up a resistance to the product you use.

Here is a link that might be useful: Immunox