Brown patch fungus is a common lawn disease that can wreak havoc on grass, particularly during warm and humid conditions. This article will delve into what brown patch fungus is, how it starts and spreads, how to identify it, and most importantly, how to treat and prevent it.

What is Brown Patch Fungus

Brown patch fungus is a disease that primarily affects cool-season grasses like tall fescue, ryegrass, and Kentucky bluegrass, but it can also impact some warm-season grasses. The disease manifests as circular patches of dead or discolored grass, which can range in size from a few inches to several feet in diameter. These patches often have a smoky-gray or dark purple border, which is a hallmark of the fungus's spread.

How Does Brown Patch Fungus Start and Spread

Brown patch fungus thrives in warm, humid environments, particularly when temperatures are above 65°F (18°C) at night and exceed 80°F (27°C) during the day. Excess moisture from heavy dew, rain, or over-irrigation, combined with high humidity, creates the perfect breeding ground for the fungus.

The fungus primarily spreads through:

1. Spores: The fungus produces spores that can be transported by wind, water, or even on garden tools and footwear.

2. Infected Plant Material: Mowing over infected areas and then moving to healthy areas can spread the fungus.

3. Soil and Water: Contaminated soil and water can facilitate the movement of the fungus to new locations.

Identifying Brown Patch Fungus

To determine if your lawn has brown patch fungus, look for the following signs:

• Circular Patches: Patches of brown or tan grass that appear circular and can vary in size.

• Grayish Ring: A smoky or dark-colored ring, often referred to as a "smoke ring," around the perimeter of the patch.

• Rapid Spread: Patches that appear and expand quickly during periods of high humidity and warm temperatures.

• Leaf Lesions: Grass blades may exhibit irregular tan or brown lesions with dark borders.

Treatment for Brown Patch Fungus

If you suspect brown patch fungus in your lawn, taking immediate action is crucial to control its spread. Here are some effective treatments:

1. Fungicides: Apply a fungicide labeled for brown patch control. Follow the manufacturer's instructions for application rates and timing. Common fungicides include azoxystrobin, myclobutanil, and propiconazole.

2. Reduce Moisture: Water your lawn early in the morning to reduce prolonged leaf wetness. Avoid evening watering.

3. Improve Air Circulation: Mow the lawn regularly to improve air circulation around the grass blades. Ensure thatch is not excessive, as thick thatch can retain moisture.

4. Fertilization: Avoid applying high-nitrogen fertilizers during peak brown patch conditions, as excessive nitrogen can exacerbate the disease. Opt for balanced or slow-release fertilizers.

Prevention of Brown Patch Fungus

Preventing brown patch fungus is more effective and easier than treating an outbreak. Implement these preventive measures to keep your lawn healthy:

1. Proper Watering: Water deeply but infrequently, providing about 1 inch of water per week. Water early in the day to allow grass to dry before nightfall.

2. Mowing Practices: Mow at the correct height for your grass type. Avoid cutting more than one-third of the grass blade length at a time.

3. Aeration: Aerate your lawn annually to reduce soil compaction and improve water infiltration.

4. Thatch Control: Dethatch your lawn if the thatch layer exceeds 0.5 inches. Excessive thatch can hold moisture and create ideal conditions for fungal growth.

5. Balanced Fertilization: Apply fertilizers according to soil test recommendations. Avoid excessive nitrogen, especially in late spring and summer.

Brown patch fungus can be a significant threat to your lawn's health and aesthetics, but with proper identification, timely treatment, and preventive measures, you can manage and mitigate its impact. By maintaining good lawn care practices and being vigilant during high-risk periods, you can keep your lawn lush, green, and free from the unsightly patches caused by this common fungal disease.

Linnemann Lawn Care and Landscaping can help you identify and treat brown patch fungus. From aeration and overseeding to fertilization and weed control, our 7-step program will help you combat brown patch fungus. Learn more about our services here and contact us at (618) 939-4769 for a consultation.