Many diseases will leave bleached-out, dead turf. When this occurs you not only lose the grass, but you also lose the opportunity to determine what caused the problem. Diseases are progressive in nature, especially during hot, humid weather. It is important to check your lawn regularly if you want to spot disease symptoms early on. Look for spots or banding, color changes, or signs of decay on grass blades. When you examine affected turf look at its shape, size, color, and texture. Does it feel slimy or dry? How are the patches distributed across the lawn? You should also give the grass a tug to check for rot. Lastly, venture out early in the morning, while the lawn is damp with dew, and look for signs of fungal mycelia. These fine, cobweb-like threads disappear with the day’s heat and sun.
Identifying lawn diseases can be difficult. Damage may not be apparent until turf is stressed by drought and heat. If your lawn’s symptoms stump you, take a sample to a reputable nursery, a Cooperative Extension Service (CSREES) lab, or your state university plant-pathology department. Before taking samples, be sure to call and obtain specific sampling instructions.
When disease does get a foothold in your lawn, you need to take immediate steps to contain it. Start by bagging your lawn clippings and not adding them to your compost pile. Next, avoid walking through infected turf, especially when it is wet. Then review your management practices to determine why your grass became susceptible and decide which actions are necessary to improve your lawn’s growth environment and alleviate the conditions that foster fungal growth. Keep in mind that as weather conditions change, they may no longer promote fungal growth, thereby allowing the problem to resolve itself naturally. If disease symptoms continue, you may decide that you need to apply a fungicide. View one of these articles, Spring through Fall Lawn Diseases, Summer Lawn Diseases, Fall through Spring Lawn Diseases to learn more about various diseases.