Many landscapers will tell you it is because our water in Arizona contains a high salt and high calcium content. That will turn white when the water evaporates causing the water to not penetrate causing run off and grass death. It takes a lot of years to build up enought salt for it to be seen on the soil surface and summer monsoon rains flush it out. If salt was the reason causing the summer grass not to grow, the winter grass would also be affected. But, they are the landscapers and you try it and it does nothing.
Next you fertilize yet nothing so you even try replanting yet nothing works. It's because those aren't the reasons why the grass will not grow. It has nothing to do with the salt content of the water, fertility of the soil, or any other problem that can be solved by softening the soil or watering more. In fact watering more caused the problem to worsen and allowed mosquitos, chiggers, & aphids, to lay eggs in the soil resulting in a potential health problem . So, what do you do?
Suntree or Indian Bend Village this exact problem with the summer grass and it has nothing to do with salt, sun, soil fertility, or any other problem that has a cheap or quick fix. The photo below shows the plugs left on the lawns after landscapers aerated in 2011. All the plugs came from the same area in the same lawn where the grass will not grow in the summer. Notice one of the plugs has a something white on top and at the root zone below (previously joked about being bird poop). Notice that the entire plug isn't white and not all of them are white. That is because it isn't salt build up; it is one or more kinds of fungi.
Once Suntree Board Members start taking an active interest in the community and begin researching the problem themselves. They will figure out they have to take matters into their own hands and sends soil samples they collected themselves using sterile tools for testing to a facility (not ASU) to determine what kind of fungus it is and how to treat it, the problem will just continue to grow.
I just don't understand why people are so quick to run to the doctor for something like a runny nose then refuse to believe that anything else can get sick. Plants, grass, shrubs, trees, pets, soil all get sick too. They think the only problems that plants have is from watering to little or to much, not enough sun or too much. They don't consider pests that may have infested the plant due to over watering, stress, bacterial infections, viral infections, and certainly not fungus. All plants need water, sun, and be able to obtain air through the roots. If the soil is compact and hard the roots cannot get air and they will come to the surface to get it or die out. But, more importantly, they need soil that drains and dries out between waterings, is free from fungus, bacteria, viral infections, and undesirable pests. You can learn what different infections look like and the symptoms from the following books.
