Prepare Your Lawn for the Summer Disease Problems

If you have tall fescue for a lawn in southern Nevada, here are some tips to help prepare for the diseases that will threaten your lawn this summer.
Having a lawn in good health, just like you being in good health, is the best protection against summer diseases like summer patch.

This is summer patch on tall fescue. It used to be called "frogeye" patch or the more knowledgeable might call it Fusarium patch. The name "Fusarium patch" was thrown out several years ago when it was found not really a correct name for it.

The disease starts as some brown areas that start dying in different spots. Then the brown spots coalesce or grow together into this patchwork of dead grass, frequently leaving behind a small clump of grass that is not affected. This gave it the "frogeye" name.

You can access the fact sheet I wrote while at the University of Nevada here.  Otherwise you can find it here. Summer Patch fact sheet

Prevention. An ounce of prevention... and that is true in this case.
Get your fertilizer levels up and adequate. I believe the rates of fertilizer recommended for lawns is way too high. You can reduce that to 50% of what they recommend if you use a mulching mower (you dont bag the clippings it just falls back into the grass). You do need a good mulching mower or at least a mulching blade on your mower.

Aerate. Aeration opens the soil up so the roots can "breathe". This promotes a deeper root system, more heat tolerance and improved disease resistance. Ideally this should be done in about March but if you have not had it done before, do it now. There used to be a landscape maintenance service in Las Vegas that offered this service. Otherwise you will have to rent a gasoline driver aerator from places like Aherns or buy a hand operated aerator and do it by hand. If you go this route it is not hard to do. Just time consuming. Wet the lawn thoroughly and start plugging away. It is good to follow up this activity with a light application of a phosphorus fertilizer and water it in.

The correct kind of aerator will leave soil cores behind that you will have to rake up and put in a compost heap.

Adjust or correct your sprinklers. Any weakness in your lawn sprinklers you will see now that it is getting hot. Before when it was cool you could sail through this period. As it gets hotter the weak spots will show up as grey green areas between irrigations. (It is grey green because the grass is wilting because your irrigation system was inadequately designed and/or installed.) I don't know HOW MANY times I have spoken to homeowners that assured me the "sprinkler system" was done right because they did it! My face or voice didnt show it but I was smiling inside. Occasionally, after a couple of questions, I will run into someone who did it right but that is far and few.

This is typical of a lawn with a poorly designed or installed irrigation system.

 No guarantees. I cannot guarantee success with this next approach but if I had a lawn this is what I would try. I would get or rent a compost spreader (a fertilizer spreader that you push should work as well) and purchase some high quality compost.

Compost spreader

If I were to send you somewhere in Las Vegas to get the compost, it would be at Viragrow. Get the compost with the finest texture they have so it will pass through the spreader. With this compost spreader I would spread about 1/4 inch of compost over the lawn and water it in thoroughly. I would do this once a month. Next year use this in place of buying a fertilizer. I think you will see a big change in the lawn's health and appearance. There is a significant amount of research that points to disease reductions in lawns by topdressing with compost several times during the growing season.

The Disease has Started
If this is the case, you have no choice but to use a fungicide to prevent the spread of the disease. Fungicides will not cure the disease but it should stop it from going further. There are fungicides available at nurseries for you to use. Pick one that says it helps prevent summer patch disease or they make call it "frogeye" or fusarium patch disease.