What is this???

[ple_1969]

When mowing today I noticed a good amounts of spots on my lawn that are starting to turn yellow/brown. Could this be a fungus? I took a 2 blades of grass and took a picture. I appreciate any help that I can get. Oh, I live in northern NJ and its been mild with a decent amount of rain fall.

Pete

[All Season Bill]

You definately have a disease in your lawn and by the girdling in the middle of the grass blade it looks like Dollar Spot.
The reasons? Well it could be many! Warm temperatures, high humidity, too much moisture and/or too much thatch plus a nitrogen defeciency.
Aerate your lawn and fertilize it with a higher nitrogen fert. You can spray a fungicide which will stop production but the grass needs to grow out of it.

[Smallaxe]

High N typically generates a fungal disease...

How will more N defeat Dollar Spot?

[All Season Bill]

I didn't say high N. Just a little bit more will allow the grass to grow out of it. That should work for Red Thread too

[Smallaxe]

I found this quote...

"...Dollar spot symptoms occur anytime from early to late summer. The disease usually reaches peak activity when air temperatures are in the 80° F range and under high humidity. Symptoms also may appear in the fall. The most severe cases of dollar spot occur on turf receiving closely-spaced summer irrigation. The disease may also occur on nonirrigated turf when humidity is high from prolonged muggy summer weather. Dollar spot is more severe under nitrogen deficiency or when grass grows slowly..."

It appears the cause is moisture and temperature, and a deficiency of N slows the growth and allows the fungus to become more severe.
The deficiency of N is not the cause, according to this report.
Do you irrigate often?
Do you believe your soil is N deficient?