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  • Writer's pictureJonathan Stoddard

All About Brown Patch Fungus

Brown Patch Fungus
Brown Patch Fungus

UPDATED 11/15/2023

As Brown Patch season officially kicks off with cooler temperatures and excessive moisture, we at Imperial Pest Prevention are excited to announce the yearly update of our comprehensive blog post "All About Brown Patch Fungus." This timely update is part of our commitment to providing you with the most current and effective strategies to manage and combat this common lawn issue. Stay informed with our latest insights and tips, and keep your lawn healthy and lush even during the challenging Brown Patch season!

As the much-awaited cooler temperatures roll in and we get that much-needed break from the Florida sun, We now encounter that fungus that loves these conditions. Fungus! Yes, that is correct, not just any fungus, but Brown Patch Fungus. Brown Patch Fungus, scientifically known as Rhizoctonia solani, is a common turfgrass disease that affects a wide range of grass types. It's particularly prevalent in warm, humid climates and is known for the damage it can cause to lawns and golf courses. Here's an in-depth look at Brown Patch Fungus:

What Does Brown Patch Fungus Look Like?

Brown Patch Fungus, caused by the fungus Rhizoctonia solani, has a distinctive appearance on turfgrass, making it relatively easy to identify. Here's what it typically looks like:

  • Circular Patches: The most notable feature is the formation of circular or irregularly shaped patches in the grass. These patches can vary from a few inches to several feet in diameter.

  • Color: The affected grass within these patches turns brown, tan, or yellow, signifying damage or death of the grass blades. The color may vary slightly depending on the grass type and the stage of the disease.

  • Smoke Ring: In the early morning, especially when dew is present, you might notice a dark, grayish-purple border or halo around the edge of the patches. This "smoke ring" appearance is a classic symptom of Brown Patch Fungus, but it's not always present.

  • Grass Texture: The grass in these patches often appears wilted or slimy. If you pull on the affected grass, it may easily come off, leaving bare patches.

  • Center Recovery: In some cases, the center of the patch may recover or remain uninfected, creating a doughnut-shaped pattern in the lawn.

  • Leaf Sheath Discoloration: Upon closer inspection, you may notice that the leaf sheaths (the lower part of the blade where it wraps around the stem) become rotted and dark.

Remember, while Brown Patch Fungus is distinctive, similar symptoms can be caused by other lawn diseases or issues. Proper diagnosis is important for effective treatment. If unsure, it might be beneficial to consult a lawn care professional for accurate identification and advice on management.

What is Brown Patch Fungus?

brown patch fungus

Brown Patch Fungus, scientifically known as Rhizoctonia solani, is a common fungal disease affecting various turfgrasses. This fungus is particularly active in warm, humid conditions and is known for causing significant damage to lawns and other grassy areas. Here are some key aspects of Brown Patch Fungus:


  • Appearance: It manifests as circular patches of dying or dead grass that can range from a few inches to several feet in diameter. These patches often have a brown, tan, or yellowish appearance, with a possible "smoke ring" border that is darker or more purple in color.

  • Conditions for Development: Brown Patch Fungus thrives in temperatures between 70-90°F (21-32°C), especially when combined with high humidity or extended periods of wetness on the grass.

  • Affected Grass Types: It can affect many types of grass, but is particularly harmful to cool-season grasses such as ryegrass, tall fescue, and Kentucky bluegrass. Warm-season grasses like Bermuda and St. Augustine grass can also be susceptible.

What Causes Brown Patch Fungus

  • Warm and Humid Conditions: The fungus is most active when air temperatures are between 70-90°F (21-32°C), especially during periods of high humidity. Nighttime temperatures that remain above 60°F (15°C) can be particularly conducive to the development of brown patch.

  • Extended Leaf Wetness: Extended periods of wetness on grass blades, whether from over-irrigation, poor drainage, dew, or rain, create an ideal environment for the fungus to grow and spread.

  • Poor Air Circulation: Areas with limited air movement can trap moisture around the grass, promoting fungal growth.

  • Dense Thatch: A thick layer of thatch can hold moisture and restrict airflow to the soil, creating conditions that favor the growth of brown patch fungus.

  • Excessive Nitrogen: Over-fertilization with high-nitrogen products can cause lush, tender growth that is more susceptible to infection by the fungus.

  • Soil Compaction: Compacted soil can hinder drainage and root growth, exacerbating the moist conditions that allow the fungus to thrive.

  • Stress on Turf: Grass that is under stress from factors such as drought, heat, or wear is more vulnerable to brown patch and other diseases. Management of these conditions through proper watering practices, aeration, thatch control, balanced fertilization, and stress reduction can help prevent the occurrence of brown patch fungus or at least mitigate its impact on turfgrass.

Homeowner Tips When Dealing With Brown Patch Fungus

fungus in grass blade closeup

Dealing with Brown Patch Fungus in your lawn can be challenging, but as a homeowner, you can employ several effective strategies to manage and prevent its spread. Here are some key tips:

  • Adjust Irrigation: One of the primary causes of Brown Patch Fungus is excessive moisture. If you notice signs of the disease, turn off your irrigation system and allow the lawn to dry out properly. Over-watering can exacerbate the condition, so it's crucial to ensure that your lawn isn't receiving more water than it needs.

  • Watering Schedule: When you do water, do so early in the morning. This allows the grass to dry out over the course of the day, reducing the likelihood of fungal growth which thrives in damp, overnight conditions.

  • Avoid Foot Traffic: When your lawn is suffering from Brown Patch Fungus, it's more vulnerable to damage. Avoid walking on the affected areas as much as possible. Foot traffic can stress the grass and spread the fungus to healthy areas of your lawn.

  • Careful Mowing: Mow the lawn only when it's dry. Mowing a wet lawn can spread the fungus and further stress the grass. Also, make sure to clean your mower after use to prevent spreading the fungus to other areas of your yard.

  • Mowing Height: Keep your grass at an appropriate height for its species. Cutting it too short can stress the grass, making it more susceptible to diseases like Brown Patch Fungus.

  • Aeration: If your lawn has compacted soil or thick thatch, aerate it to improve drainage and air circulation. This can help reduce the conditions that Brown Patch Fungus thrives in.

  • Fungicide Use: In cases where cultural controls are not enough, consider applying a fungicide. It's best to use these products as a preventive measure or at the early stages of the disease. Always follow the manufacturer's instructions for application.

  • Nutrient Balance: Ensure your lawn is receiving a balanced diet of nutrients. Over-fertilization, particularly with high-nitrogen fertilizers, can encourage the growth of Brown Patch Fungus.

  • Remove Dew: If feasible, manually remove dew from the grass in the mornings using a hose or lawn roller. This can help reduce the moisture levels on the grass blades. By following these homeowner tips, you can effectively manage Brown Patch Fungus and maintain a healthy, attractive lawn. Remember, prevention and early intervention are key to controlling this common lawn issue.

Impact of Brown Patch Fungus on Your Lawn

Brown Patch Fungus, caused by the fungus Rhizoctonia solani, can significantly impact your lawn. Understanding these effects is crucial for effective lawn care and maintenance. Here's an overview of the impact Brown Patch Fungus can have:

Aesthetic Damage

  • Unsightly Appearance: The most immediate and noticeable impact is the aesthetic damage. Brown Patch Fungus creates large, circular, brown or tan patches in the lawn, which can be unsightly and diminish the overall appearance of your yard.

  • Irregular Lawn Texture: The patches can cause an uneven texture in your lawn, with affected areas appearing sunken or thinner than the surrounding healthy grass.

Health of the Grass

  • Grass Health: The fungus attacks the grass at the crown and root level, potentially killing the grass in affected areas. This can lead to thinning of the turf and a reduction in the lawn's overall health and resilience.

  • Increased Vulnerability: Infected areas become more susceptible to other diseases and pests, as the fungus weakened and stressed the grass.

Spread and Severity

  • Rapid Spread: Under favorable conditions (warm, humid weather and moist grass), the fungus can spread rapidly, enlarging existing patches or creating new ones.

  • Recurring Problem: Once established, Brown Patch Fungus can be a recurring problem, especially in regions with climates that support its growth. Yearly outbreaks are common in susceptible lawns.

Recovery and Repair

  • Difficulty in Recovery: Recovery from Brown Patch Fungus can be slow, especially if the grass has been severely damaged or killed. Reseeding or re-sodding may be necessary in areas where the grass has died.

  • Cost of Treatment: Managing and treating Brown Patch Fungus can involve costs, including fungicides and possibly professional lawn care services. Preventive measures also require time and resources.

What Does Imperial Pest Prevention Do for Brown Patch Fungus?

imperial pest prevention logo

Imperial Pest Prevention is crucial in managing and addressing Brown Patch Fungus, a common issue in many lawns. It's important to understand that lawn fungus like Brown Patch is soil-borne and always present in the environment. This means that the occurrence of such fungal issues is not due to the fault of lawn care or spray companies, but rather a natural part of the ecosystem.

Imperial Pest Prevention's Approach to Brown Patch Fungus

  • Understanding the Nature of Fungus: Imperial Pest Prevention acknowledges that fungi are naturally occurring and can flare up under certain weather conditions, particularly those provided by Mother Nature. Warm, humid conditions are especially conducive to the growth of Brown Patch Fungus.

  • Timely Addressing of Fungal Outbreaks: While preventing fungi entirely is impossible, Imperial Pest Prevention focuses on addressing fungal issues as they occur. Their team is trained to recognize the early signs of Brown Patch Fungus and take immediate action.

  • Fungicide Application: When Brown Patch Fungus is identified, Imperial Pest Prevention employs appropriate fungicide treatments. They use products that are effective against this particular fungus, applying them in a manner that is both safe and adheres to environmental guidelines.

  • Cultural Practices: Alongside fungicide application, Imperial Pest Prevention advises on and helps implement cultural practices that can help mitigate the severity of fungal outbreaks. This includes recommendations on proper watering, mowing, and aeration practices to create less favorable conditions for fungus growth.

  • Educational Approach: Educating clients is a key part of Imperial Pest Prevention’s strategy. They inform homeowners about the nature of lawn fungi, the factors that contribute to their growth, and the steps that can be taken to manage their presence in the lawn.

  • Customized Lawn Care Plans: Recognizing that each lawn is unique, they offer customized care plans tailored to the specific needs and challenges of each property, considering factors such as grass type, soil condition, and local climate.

  • Ongoing Monitoring and Maintenance: After treatment, Imperial Pest Prevention continues to monitor the lawn for any signs of recurrence. They provide ongoing maintenance advice to help keep the lawn healthy and reduce the likelihood of future outbreaks.

  • Honest and Transparent Communication: Imperial Pest Prevention believes in honest and transparent communication with their clients. They make it clear that while they can effectively address fungal issues, complete prevention of naturally occurring fungi is not feasible.

By adopting these practices, Imperial Pest Prevention ensures that they are not just treating the symptoms of Brown Patch Fungus, but also helping to improve the overall health and resilience of the lawns they care for. Their approach combines immediate treatment with long-term prevention strategies, providing a comprehensive solution to this common lawn care challenge.




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