Brown patch is a common fungus disease on lawns and can spread quickly after they initially appear. Bermuda grass can turn brown when night temperatures exceed 68 degrees Fahrenheit, day temperatures exceed 80 degrees and the grass has been heavily fertilized. It is important to manage Bermuda grass well, ensuring that excessive nitrogen is not applied and that it is watered only when the soil is dry.
Brown patch spots are small to begin with but can enlarge rapidly, particularly in warmer climates. Brown patches often manifest themselves in rings of brown, dead grass surrounding green healthy grass. Other reasons for brown patch include soggy areas, hard soil and lawn mower fuel spills. Over-watering of the lawn is also a common cause, so a change in irrigation habits is often recommended.
Ideally, a lawn should be given a deep soak once a week. It is important to properly identify brown patch because the purchase of expensive fungicides can be detrimental if done prematurely. The grass will be brown all the way to the crown, where it sticks out of the Earth. Grass can be sent to local extension offices to be conclusively tested by professionals to ensure that no false diagnosis has taken place.