Every lawn in Georgia, new or established, is susceptible to a variety of disease. Promoting healthy growth is the best way to prevent a severe disease outbreak. Most common lawn diseases can be avoided by optimizing mowing and watering practices. Stressed grass is much more susceptible to disease than healthy grass.
The fungus that causes lawn disease is in the soil. You cannot eliminate this fungus, it is always there. However infection will not occur unless the environmental conditions are conducive to disease development. The first thing you should do is determine what conditions are causing the disease and if we can control them. Watering, mowing, and proper nutrition are thing we can control. Heat, humidity, drought, and excessive rainfall are conditions that can cause disease and are out of our control.
Treating with fungicide
Diseases can cause major damage to a lawn if not properly treated. Fungicides are designed to help prevent and cure disease. A fungicide will help protect a lawn while conditions are favorable for disease development. However fungicides only last for 7 to 28 days depending on the fungicide you choose. If the conditions causing the disease are still there after the fungicides length of control, you will need to re-apply the fungicide.
Here are a couple of the most common lawn diseases in our area:
Brown Patch (Large Patch) http://extension.uga.edu/publications/detail.cfm?number=B1233#BrownPatch
Spring Dead Spot (SDS) http://extension.uga.edu/publications/detail.cfm?number=C1012