Brown spots or dead areas in lawns can be common during summer months. It might be a disease, but then again, it could be something else. The three primary reasons that lawns develop brown spots or dead areas are due to irrigation problems, the development of diseases and insect damage. Disease Problems. In the hot, Mojave desert of the Southwest diseases are less likely than in wetter climates but they sometimes still occur. Most lawn diseases in our hot, desert climate occur when high temperatures collide with increasing humidity in the air. This is not the only ingredient for a disease to occur. The lawn must be susceptible to that disease. Typical summer patch symptoms Diseases problems are best solved through prevention. This is through managing the lawn to minimize diseases and using the correct fungicide when a disease problem is imminent. We influence a lawn’s susceptibility to disease by how we manage it. Here are some management decisions that you can follow to reduce disease problems to your lawn. Try to implement as many as possible. 1.     Finish watering just before sun up. 2.     Mow at the proper height and use a sharp blade. 3.     Aerate two months before the heat arrives. 4.     Use compost-based fertilizers monthly. 5.     Disinfect mower blades if you mow a suspected diseased area. When you suspect a disease is occurring, apply a broad spectrum fungicide (fungicide that treats many different diseases) as soon as possible. Diseases that should be listed on the label include summer patch and necrotic ring spot. They might also mention diseases such as “frog-eye” and Fusarium patch.