Lawn Diseases to Watch Out for in Late Summer

As summer winds down in Dayton, Ohio, lawns are often at their most vulnerable to various diseases. The combination of heat, humidity, and occasional rain creates the perfect environment for lawn diseases to thrive. In this blog post, we'll identify some common lawn diseases that appear in Dayton during August, such as brown patch and dollar spot, and provide treatment and prevention tips to help you keep your lawn healthy and disease-free.

Common Lawn Diseases in Dayton, Ohio

1. Brown Patch

   • Symptoms: Brown patch appears as circular, brown patches of dead grass, often with a darker ring around the edge. Patches can range from a few inches to several feet in diameter.

   • Causes: This disease is caused by the fungus Rhizoctonia solani, which thrives in hot, humid weather and poorly drained soils.

   • Treatment: Apply a fungicide specifically labeled for brown patch. Water early in the morning to reduce leaf wetness, and avoid over-fertilizing with nitrogen.

2. Dollar Spot

   • Symptoms: Dollar spot manifests as small, silver-dollar-sized patches of bleached or straw-colored grass. These patches can merge to form larger, irregular areas of dead grass.

   • Causes: The fungus Sclerotinia homoeocarpa causes dollar spot, thriving in warm, humid conditions and during periods of drought stress.

   • Treatment: Apply a fungicide labeled for dollar spot. Improve lawn aeration and avoid watering in the late afternoon or evening. Maintain balanced fertilization to prevent nutrient deficiencies.

3. Pythium Blight

   • Symptoms: Pythium blight appears as water-soaked, greasy patches of grass that can rapidly expand. Infected grass may collapse and form a matted, cottony growth under high humidity.

   • Causes: Caused by Pythium spp. fungi, this disease favors hot, wet, and humid conditions, especially in poorly drained areas.

   • Treatment: Apply a fungicide labeled for Pythium blight. Improve drainage and avoid excessive nitrogen fertilization. Water deeply and infrequently, early in the day.

4. Leaf Spot

   • Symptoms: Leaf spot presents as small, dark, water-soaked lesions on grass blades that eventually turn tan or brown with dark borders. Severe infections can cause thinning and dieback.

   • Causes: Multiple fungi, including Bipolaris and Drechslera species, cause leaf spot, often under conditions of high humidity and excessive thatch.

   • Treatment: Apply a fungicide labeled for leaf spot. Reduce thatch through aeration and dethatching. Water early in the morning and avoid prolonged leaf wetness.

5. Red Thread

   • Symptoms: Red thread appears as small, reddish or pinkish threads on the grass blades. Infected areas may have a reddish tinge and can lead to patches of dead grass.

   • Causes: The fungus Laetisaria fuciformis causes red thread, thriving in cool, moist conditions and lawns with low nitrogen levels.

   • Treatment: Apply a fungicide labeled for red thread. Fertilize with nitrogen to promote healthy grass growth. Improve air circulation and reduce moisture retention on the lawn.

Prevention Tips

1. Proper Watering

   • Water deeply and infrequently, aiming for about 1-1.5 inches of water per week, including rainfall. Water early in the morning to allow grass blades to dry before evening, reducing the risk of fungal growth.

2. Mowing Practices

   • Mow at the correct height for your grass type, usually around 3-4 inches. Keep mower blades sharp to ensure a clean cut and reduce stress on the grass. Avoid mowing when the grass is wet.

3. Fertilization

   • Follow a balanced fertilization schedule, applying nitrogen at appropriate times to promote healthy growth without encouraging disease. Avoid excessive nitrogen fertilization, which can lead to lush, disease-prone growth.

4. Aeration and Thatch Control

   • Aerate your lawn to improve soil drainage and reduce compaction. Dethatch if necessary to prevent excessive thatch buildup, which can harbor fungi and limit water penetration.

5. Good Lawn Hygiene

   • Remove grass clippings and debris that can harbor disease-causing organisms. Clean and disinfect lawn equipment regularly to prevent the spread of pathogens.

Treatment Options

1. Fungicides

   • Use fungicides as a preventive measure or to treat active infections. Choose products labeled for the specific disease you’re targeting and follow the manufacturer’s instructions carefully.

2. Cultural Practices

   • Implement proper lawn care practices, such as mowing, watering, and fertilization, to create a healthy environment that resists disease. Address underlying issues like poor drainage or compacted soil.

3. Professional Help

   • If lawn diseases persist or worsen, consider hiring a professional lawn care service. Experts can diagnose the problem accurately and apply targeted treatments to restore your lawn’s health.

By staying vigilant and implementing these strategies, you can effectively manage and prevent common lawn diseases in Dayton, Ohio, during the late summer months. A healthy, well-maintained lawn is your best defense against disease, ensuring your yard remains lush and vibrant well into the fall.