Identifying and Treating the 2 Most Common Lawn Diseases

Even well-maintained turf can sometimes be troubled with a lawn disease. When the right combination of pathogens, environmental factors, and susceptible grass coincide, plant diseases can gain a foothold. As an expert in lawn care, Dempster Brothers Lawn Care & Landscaping of Knoxville provides recommendations for identifying and treating lawn disease in Tennessee.

The first step in preventing the problem is identifying the specific disease infecting your lawn. Two of the most common lawn diseases in Tennessee are brown patch and dollar spot. Here’s how to identify and treat them.

1. Brown Patch

Brown patch is a common lawn disease that may cause grass blades to turn brown and die back. However, grass crowns are rarely killed.

• Cause: A fungal disease caused by Rhizoctonia solani, often triggered by high humidity, warm temperatures (65–85°F), and overwatering.
• Symptoms: Circular patches of brown or tan grass, often with a darker outer ring (“smoke ring”) visible in the morning.
• Treatment: Treatment for brown patch is a four-step process:
• Reduce Watering: Avoid overwatering by watering early in the morning to allow grass to dry during the day.
• Improve Airflow: Aerate compacted soil and remove thatch buildup to improve drainage.
• Fertilize Appropriately: Avoid applying excess nitrogen during the warm months, as it can fuel fungal growth.
• Apply Fungicide: Use a fungicide labeled for brown patch, especially in severe cases or as a preventive measure during high-risk seasons.

2. Dollar Spot

Dollar spot is another common lawn disease, often mistaken for a smaller version of brown patch due to its circular patches of discolored grass. It presents small circular spots of dead grass that are about the size of a dollar coin. The infected grass usually looks bleached or tan.

• Cause: A fungus called Sclerotinia homoeocarpa, which thrives in lawns with low nitrogen levels and during warm days with cool nights.
• Symptoms: Small, silver-dollar-sized patches of straw-colored grass. These spots may merge into larger areas if untreated.
• Treatment: Like brown patch, treatment for dollar spot involves four steps:
• Fertilize Properly: Apply a balanced fertilizer to ensure the lawn has adequate nitrogen.
• Water Wisely: Water deeply but less frequently, and avoid watering in the evening to prevent prolonged moisture on the grass.
• Mow Regularly: Keep grass at the recommended height for its type but avoid cutting it too short.
• Apply Fungicide: Use fungicides specific to dollar spot if cultural practices don’t resolve the issue. Rotating fungicides can prevent resistance.

Prevention Tips for Both Diseases

• Mow with sharp blades to avoid tearing grass, which makes it more susceptible to infection.
• Clean mower blades and tools to avoid spreading fungi.
• Overseed with disease-resistant grass varieties if problems persist.
• Avoid creating environments favorable to fungi (e.g., overwatering, over-fertilizing with nitrogen, or allowing grass to remain wet overnight).

With prompt care and the right treatments, you can maintain a healthy, attractive lawn suited to Tennessee’s unique climate. The lawn care professionals at Dempster Brothers are experts at helping you achieve and maintain a beautiful lawn. Contact Dempster Brothers at (865) 264-8925 to discuss your lawn care needs.