Can you post a picture? Preferably take the picture on a cloudy day or in the shade or when the sun is low.

Red thread thrives in nitrogen poor soil that is kept too moist. It usually goes away with the spring fertilizer and when the soil dries out. Kinda need a picture. This could be something else.

Not likely to be a mistaken ID, David -- this is the heart of the Red Thread season on LI.

I can post a picture later today. I also noticed yesterday a small pinkish glob on top of some of the blades.

So far I have stopped all watering for the past week or so. Save for a day or two of rain, the lawn has been kept dry. There are at least a dozen patches and I don't know if this goes away when the weather warms or if there is something I need to do to address it before it worsens.

Assuming this is red thread, should I fertilize again? I fertilized once already in early May.