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Brown Patch is a common fungal disease that affects St. Augustine grass, which is a warm-season turfgrass variety grown in the southern United States. Under certain conditions, the disease can also cause damage to Bermudagrass and Zoysiagrass, but it is far less common. Symptoms include circular or irregular-shaped patches of brown or yellow grass that range in size, from a few inches to several feet in diameter. The patches may have a "smoky" appearance, and the affected leaves may have a slimy, dark brown or black appearance at their base. In severe cases, the grass may die, leaving bare patches in the lawn.


Brown patch is caused by the Rhizoctonia fungi, which infects the grass foliage and crowns. This fungus colonizes the organic matter in the thatch layer, and, during times of stressful conditions, can cause disease in the grass plant. Brown Patch is most common in the summer months, when temperatures are warm and humidity is high, but it can occur any time of year when conditions are favorable for fungal growth. 





Brown Patch is very difficult to control, as it thrives in hot and humid weather conditions. In most cases, the spread of the disease will be reduced by changes in temperature and weather, but you can also adjust some cultural practices to improve the health of the lawn and limit the spread. However, depending on the size of the infestation and the scope of the damage, other forms of control may be necessary.


A thick, healthy, well-maintained lawn is the best line of defense. Here’s how you can adjust your beneficial cultural practices to reduce the spread of Brown Patch in St. Augustine grass:

  • Core Aeration: Aerating your lawn can improve soil drainage and help reduce the likelihood of lawn diseases. This will also alleviate soil compaction and allow water and nutrients to penetrate deeper into the soil.

  • Fertilize Regularly: Regular applications of Weed Man’s specially formulated, slow-release granular fertilizer will help provide your lawn with adequate nutrients. These applications are timed specifically to avoid over fertilizing the lawn.

  • Watering: Under normal circumstances, you should be watering your lawn a few times per week for 30-45 minutes in each area. During hot and dry periods, most lawns should be watered as much as required to maintain its desired green color. Always water in the early morning so the turf has time to dry by nightfall.

  • Mowing: Maintain a regular mowing schedule with a razor sharp blade. Never remove more than a ⅓ of the grass blade at each mowing.


Recommended Mowing Height

Common Bermudagrass - ¾ to 1¼ inches

Hybrid Bermudagrass - ½ to 1½  inches

Centipedegrass - 1 to 2 inches

Zoysiagrass - 1 to 2½ inches

St. Augustine - 3 to 4 inches

Fescue - 3 to 4 inches


Your local Weed Man professional may be able to offer other solutions and recommend the best form of treatment that is available to improve the conditions of your lawn.