A photo would be very helpful.

lol - I was posting to quickly and the photo's had not uploaded....

Echo kentc,,,, my first impression is that it's Bermuda. ....rising from the dead.

It looks like devil grass, er, Bermuda to me too. Grr.

Looks like Bermuda. Mow the lawn short - to remove a lot of the straw color. The tall fescue can tolerate a shorter mow in the winter. In the spring when the Bermuda starts growing again, Spray 'Bayer advanced Bermuda control' - 3 times a year- spring, early summer & early fall.

Exactly what I was thinking - the light brown stuff isn't diseased Marathon, it's bermuda grass, which is cold sensitive and goes dormant in the winter.

looks you're right, here is a runner I picked out. now the question is whether I let it take over the fescue or not. I don't care what type of grass is out there just that it's the same and green. I have St Augustine in the back yard and I overseed with annual rye with pretty good success. Any thoughts?

Absolutely common bermuda invasion.

Assuming you live in Escondido, CA, in my opinion you are just a shade too far away from the beach to be growing Marathon. If you were in Oceanside, then sure, go for it; but higher up the hill in Escondido you are out of the summer morning fog zone and should be exclusively growing something like bermuda or St Augustine. Fescue is a water hog and needs almost daily water to stay green in the summer heat. Bermuda and St Augustine can go 2 weeks easily in your area even in the heat. If you want to be part of the solution to the California water problems, then I would get rid of the fescue back where you are. My mother was in Temecula for many years, but the owner of her house insisted on Marathon...and daily watering. Now 10 years and a major drought later, he finally let his own Marathon die out.

Overseeding St Augustine with rye looks good in the winter, but there are issues with that practice. One is that the tall rye grass provides enough shade in the spring to delay the awakening of the St Aug. In fact it can delay it to death. The St Aug should awaken in late March in your area. If it does not, then it will be thinning out. Another issue is that there is a tendency to think you can play on the grass in the winter because the rye regenerates; however, the St Augustine gets beaten down and damages the ability to return at full speed in the spring.

The Bermuda will never completely take over the Fescue......you will always have a mix of the two. You can hide the Bermuda in the winter- by mowing at the lowest setting on your mower, which will scalp off the brown Bermuda and cause a lot of new leafy growth on the fescue. Fertilize after scalping, and raise the mowing height back to where it was before the scalp job.

Great advice everyone! I have 3 kids and a large mortgage for my backyard so I'm invested in using it... Good info on overseeding, I will give it a low cut in March to help the Augustine come back.

Tom - thanks for the tip on Bermuda, I will follow your advice and send a follow up pick. My long term plan is to replant with UC Verde but I need to deal with some frost damaged 5 gallon Indian Laurel I just planted first.