Lawn Disease - Common Lawn and Grass Diseases

Lawn or grass diseases are very common and can be caused by a variety of factors. Unfortunately, lawn diseases can sometimes be hard to diagnose and treat. The best place to begin is with an evaluation of the symptoms of the diseased grass.

Here are six common lawn diseases and their symptoms:

• Anthracnose. Lawns that have reddish brown spots with yellow markings may have been affected by anthracnose. Spots may be anywhere from 2 inches to 20 feet in diameter. Anthracnose is a lawn disease that is commonly caused by wet or humid weather. A fungicide can be used to repair the lawn.
• Brown Patches. This grass and lawn disease is extremely common in hot weather and causes circular brown patches to appear on the lawn. Spots may be anywhere from several inches to several feet in diameter. Lawns with brown patches should be thatched, aerated, watered and sprinkled with compost.
• Fusarium Blight. Lawns that have donut or crescent shaped patches of dead or dying (reddish-brown) grass may be afflicted with fusarium blight. Fusarium blight is very similar to other common lawn diseases, but can hard to diagnose and control. Lawns should be thatched and aerated. Mowing should be kept to a bare minimum, as the grass will be better off if left high.
• Melting Out. One of the most frequent and destructive lawn diseases, melting out is caused by a fungus which can be spread by mowing, thatching, and the use of nitrogen fertilizers. This lawn disease will cause grass to wither, turn brown, and die. In some cases, purple or brown spots will appear on the grass leaves. You will most commonly see melting out when the temperature and humidity are high. Lawns may be treated with fungicide or they can be reseeded with a more resilient type of grass.
• Powdery Mildew. Caused by poor air circulation, high humidity, and dense shade, powdery mildew is a fungus that attacks grass blades and leaves. The fungus consists of a white powdery substance and will kill the grass if left unchecked. This lawn disease can be treated with fungicide.
• Rust. This lawn disease commonly occurs in hot weather and causes a reddish-orange powder to appear on the grass. Severe rust will cause the grass to turn yellow and die. With adequate mowing, fertilization, and irrigation, this lawn disease can be easily controlled.