Generally you can tell grub damage because you don't see it until fall, so that rules it out for your current issue. Fungus is a possibility. Since you live in OK you probably get a lot of wind. That often (but not always) rules out fungus which likes it more calm. But you say east OK. Does that mean you live in the hills? It could be you don't get enough air circulation and you have a fungus.

My general rule for getting the soil tested is only do it when you can't grow ANYTHING. Well, you can't grow anything. Time to see what your soil is like.

Since you noticed large brown areas the day after you fertilized, I'm wondering if you might be over-fertilizing.

How much of the fertilizer did you put down and how many square feet is your lawn (not your lot size, since that includes the house, driveway, sidewalks, landscaping, etc)? Either measure the lawn or measure all the non-lawn areas and subtract that from the lot.

Are these spots circular in shape? There are some fungi that create circular patterns.

Can you post a picture of the lawn?

hi, i don't have a camera yet to post photos, but the ag guy came over and said it was brown spot, a fungi. he thinks it will die. i wish we could save it, any ideas? he said to use something that starts with a d, and we have that information, but i will there was something more. it has been raining so much that we can't even mow it. it was pretty tall when we got around to mowing this last time due to rain.

Okay I'm going to suggest an inexpensive, yet surprisingly effective, fungus treatment. Visit your local feed store (call ahead) and get a 50-pound bag of ordinary corn meal. If all they have is corn gluten meal, keep calling. The application rate if you already have the disease is 20 pounds per 1,000 square feet. Apply to the entire lawn area because corn meal is also a fertilizer - if you only applied to the affected part of the lawn you would end up with a dark green spot where the fungus was. It takes about 10 days before the disease starts to die and another 10 days before the grass starts coming in green again. That is 3 full weeks so try to relax while it's working. If you have used any chemical fungicide or sulfur or sulfate products recently, the corn meal will not work.

I have had a recurring fungus problem every spring since I moved here in 1992. I finally tried corn meal in 2001, and that was the first thing that ever worked for me. I no longer worry about the cause of my problem. I just look for the first signs of the disease and hit it with corn meal - problem solved until next time. In fact the effectiveness of corn meal both as an antifungal and as a fertilizer is what caused me to convert to an organic lawn care program.

You can apply corn meal any day, any time, rain or shine.

great. i am going to the farm supply store and get 50 lbs. i will put it on heavy. my husband can do the math. thanks so much.

p.s. my husband was concerned because we just fertized the lawn with triple 19 and wonder if that would cause the corn meal to not work?