Fusarium

One of many fungi that hurt lawns, fusarium affects lawns and crops.

It is more prevalant on cool season grasses (Fescue, bluegrass,Rye)

It can make circles or crescent marks or even streaks.

This disease does it's biggest damage in hot, humid weather.

When winter comes, it survives  in the thatch

that chemical lawns cannot decompose.

So if the syptoms cease when the weather cools,

don't get too excited, as they'll be baaack.

Another thing that feuls fusarium is the daily watering

that chemical lawns depend on.