If there are brown spots on your lawn, repairing them and preventing them from returning can be an exercise in frustration. Even though all of these spots may look the same, each one may be caused by a different factor – meaning that you probably won’t be able to treat each brown spot in the same way. However, the reasons that these spots develop are fairly predictable. Read on for some of the most common causes – and treatments – for lawn brown spots:

Dog Urine

Unfortunately, many people walk their dogs on the first lawn that they can find. While this isn’t the dog's fault, chemicals in their urine can cause the grass in the affected areas to die off. If you see a dog walker on your lawn, try to find out who they are and politely advise them that they are trespassing on private property and causing damage to your lawn. Let them know that they’ll receive a bill from you as a result of any repairs you need to make. Most accidental offenders will steer clear of your lawn in the future.

The necrotic ring spot fungus (Leptosphaeria korrae) affects several species of grasses, especially during the cool seasons. To keep a healthy lawn during this kind of weather, you need to recognize and stop this fungus before it damages your entire lawn.Necrotic Ring Spot

The symptoms of the fungus usually appear in late spring or early autumn. The fungus starts out as light green patches ranging from 5 to 10 centimeters in diameter. They can grow to a full meter in diameter and may turn light or reddish brown in color. Streaks, semi-circular, and circular patterns show up in the affected areas of the lawn.

Spruce Galls are formed by small insects who feed on the vegetation of Spruce trees. There are two types of insects which cause spruce galls to form, the Cooley Spruce Gall Adelge, and the Eastern Spruce Gall Adelge/ These two families of insects cause harmful galls to form at the tips of spruce stems. These galls can be 1-2 inches long and almost an inch in diameter when fully developed. They are dangerous as these galls are a form of infestation on the tree and begin to kill the vegetation of the tree.

Rhizoctonia (or Large Brown Patch) is present in most types of soils. This soilborne fungus attacks several plant types including grasses, vegetables, flowers, and even field crops. It usually appears in highly fertilized soils of plants that are covered with a film of moisture for at least 12 hours each day. Other conditions that promote Rhizoctonia growth are a temperature of 70-95 F for several hours each day, and the infection of the fungus from contaminated soil.Bluegrass Rhizoctonia solani