Red Thread Disease: Protecting Your Lawn from Fungal Invasion

We all want a vibrant green lawn, so when your grass starts turning pink, you know something is up! Among the many threats to a healthy lawn, red thread disease stands out as a common and troublesome problem. This fungal disease not only mars the appearance of your lawn with unattractive pink or reddish threads but also weakens the grass, making it more susceptible to other issues. 

Understanding red thread disease and knowing how to manage it is essential for keeping your lawn in top condition. In this article, we'll explore what red thread disease is, how to identify it, and the best strategies for prevention and treatment, helping you ensure your lawn remains vibrant and healthy all year round.

What Is Red Thread Disease?

Red thread disease, scientifically known as Laetisaria fuciformis, is a fungal infection that commonly affects lawns. This disease is particularly notorious for the distinctive red or pinkish threads it produces, which can be a clear indicator of its presence.

Symptoms and Visual Identification

characteristic feature of red thread disease

One of the first signs of red thread disease is the appearance of small, irregularly shaped patches of discolored grass. These patches often start as light brown or tan and can expand over time, creating larger areas of damaged turf.

The most characteristic feature of red thread disease is the pink or reddish thread-like structures that extend from the grass blades. These threads, or "sclerotia," are the fungal fruiting bodies and are typically more visible when the grass is wet or during periods of high humidity.

In addition to the reddish threads, you might notice:

  • Grass blades with pinkish-red tips or lesions.
  • Thinning grass in the affected areas.
  • Patches of grass that seem to struggle despite regular care.

How It Affects Different Types of Grasses

Red thread disease can affect various types of grasses, but it is most commonly seen in cool-season grasses such as:

  • Perennial Ryegrass
  • Kentucky Bluegrass
  • Bentgrass
  • Fescues

While warm-season grasses are less susceptible, they are not entirely immune. The impact on the lawn can vary depending on the grass type, the severity of the infection, and the environmental conditions. So, if you are wondering why your grass is turning red, red thread disease may be the culprit.

Environmental Conditions that Promote Red Thread Disease

Environmental Conditions that Promote Red Thread Disease

Red thread disease primarily favors cool, damp weather. It typically occurs in the spring and fall when temperatures range between 60°F and 75°F (15°C to 24°C), and there is ample moisture from dew, rain, or irrigation. These conditions create an ideal environment for the fungus to grow and spread.

Poor Soil Fertility

One of the most significant factors contributing to red thread disease is poor soil fertility, particularly nitrogen deficiency. Lawns that are not adequately fertilized with nitrogen are more susceptible to this disease. Nitrogen is crucial for healthy grass growth, and a lack of it can weaken the grass, making it more vulnerable to fungal infections.

Compacted Soil and Poor Drainage

Compacted soil restricts root growth and reduces the grass's ability to absorb water and nutrients. This stress can weaken the grass and make it more susceptible to red thread disease. Poor drainage further exacerbates the problem by creating a persistently damp environment, ideal for fungal growth.

Spread and Lifecycle of the Fungus

The red thread fungus spreads through infected grass clippings, water, and wind. It can survive on infected plant debris and in the soil, making it difficult to eradicate once established. The lifecycle of the fungus involves the production of sclerotia, which can remain dormant in the soil during unfavorable conditions and become active when conditions improve.

The fungus overwinters in the thatch layer and soil, and once the weather becomes conducive, it begins to infect new grass blades. Understanding this lifecycle is crucial for effectively timing your prevention and treatment efforts.

Related: Muddy Backyard Solutions: How to Help Drainage for Lawns

Prevention Strategies for Red Thread Disease

Preventing red thread disease is often more manageable and cost-effective than treating an established infection. 

Regular and thorough lawn maintenance is the cornerstone of preventing red thread disease. Consistent care not only promotes strong, resilient grass but also reduces the likelihood of fungal infections. A well-maintained lawn is less stressed and better equipped to fend off diseases.

Best Practices for Prevention

  1. Regular Mowing with Sharp Blades
    • Keep your lawn mowed to the appropriate height for your grass type, usually between 2.5 to 3.5 inches.
    • Ensure your mower blades are sharp. Dull blades can tear the grass, creating open wounds that make it easier for the fungus to infect.
    • Avoid cutting more than one-third of the grass blade length at a time to minimize stress on the grass.
  2. Adequate fertilization schedules
    • Apply a balanced fertilizer with an appropriate amount of nitrogen to promote healthy grass growth.
    • Conduct a soil test to determine nutrient deficiencies and adjust your fertilization plan accordingly.
    • Avoid over-fertilization, which can lead to excessive growth and increased susceptibility to disease.
  3. Aeration to reduce soil compaction
    • Aerate your lawn at least once a year to alleviate soil compaction and improve air, water, and nutrient movement to the roots.
    • Core aeration, which removes small plugs of soil, is particularly effective.
  4. Proper watering techniques
    • Water deeply and infrequently to encourage deep root growth. Aim for about 1 inch of water per week, including rainfall.
    • Water early in the morning to allow grass blades to dry throughout the day, reducing the prolonged leaf wetness that promotes fungal growth.
    • Avoid overwatering, which can lead to waterlogged soil and increased fungal activity.
  5. Thatch management
    • Keep the thatch layer (the layer of dead grass and organic matter between the soil and living grass) under 0.5 inches thick.
    • Dethatch your lawn if the thatch layer becomes too thick, as excessive thatch can harbor fungal spores and restrict water and nutrient movement.
  6. Grass selection and overseeding
    • Choose grass varieties resistant to red thread disease for new lawns or when overseeding.
    • Regularly overseed your lawn to maintain a dense, healthy stand of grass that can outcompete weeds and resist disease.

By implementing these preventive measures, you can significantly reduce the risk of red thread disease and maintain a healthy, attractive lawn. 

Related: Turf Wars: How to Treat Lawn Fungus

Fungicide Treatment and Management

fungicide treatment and management for red thread disease

If red thread disease has already taken hold in your lawn, prompt and effective treatment is essential to control its spread and minimize damage. Fortunately, several strategies and products can help you manage this fungal infection and restore your lawn's health.

Treatment Options

  1. Fungicides: When and how to use them
    • Fungicides can effectively control red thread disease, especially in severe cases.
    • Select a fungicide labeled for red thread disease and follow the manufacturer’s instructions carefully.
    • Apply fungicides when conditions are favorable for the disease, such as during cool, damp weather.
    • Ensure thorough coverage of the affected area to maximize the fungicide's effectiveness.
  2. Natural and organic remedies
    • Compost tea: Applying a compost tea made from high-quality compost can introduce beneficial microbes that outcompete the red thread fungus.
    • Neem oil: Neem oil has antifungal properties and can be applied to the lawn to help reduce fungal activity.
    • Baking soda solution: A mixture of baking soda and water sprayed on the affected areas can alter the pH and create a less favorable environment for the fungus.

Product Recommendations

Selecting the right products is crucial for preventing and treating red thread disease effectively. From fungicides to fertilizers and biosimulants, using high-quality lawn care products can make a significant difference in maintaining a healthy lawn. 

We offer a comprehensive range of products designed to keep your lawn disease-free and thriving. Below are some top recommendations specifically for managing red thread disease.

Fungicides Effective Against Red Thread

1. Pillar® SC Liquid Fungicide


Pillar® SC fungicide combines the strength of two active ingredients, triticonazole, and pyraclostrobin, in one powerful broad-spectrum solution. It provides fast curative activity and long-lasting residual control for up to 28 days.


  • Controls a wide range of lawn diseases, including red thread, brown patch, dollar spot, and more (see full list above).
  • Easy to mix liquid formulation with a simple application rate of 1 oz per 1000 square feet, suitable for both preventative and corrective disease control.
  • Ensures uniform application without separation or clogging during spraying.

Recommended usage:

  • Suitable for all grass types, including cool season (Kentucky Bluegrass, Tall Fescue, Ryegrass) and warm season (Bermuda, St. Augustine, Zoysia, Centipede, Bahia) lawns. 
  • Apply as early as April or May and later in the season as needed, following label instructions for optimal timing and application rates.
  • Use a battery-powered sprayer equipped with a large droplet nozzle for best results.

Why Choose Pillar® SC?

  • Offers a premix of two potent active ingredients for comprehensive disease control, eliminating the need for multiple products.
  • Provides efficient absorption and movement into the soil with minimal watering requirements after application.
  • Designed to enhance stress tolerance and growth efficiency of lawns, promoting resilient and high-quality grass.

2. Headway G® Granular Fungicide


Headway® G combines two active ingredients, azoxystrobin and propiconazole, to effectively control a broad spectrum of lawn-damaging fungi. This dual-action formulation provides both preventative and curative control, ensuring optimal effectiveness against diseases like red thread, brown patch, dollar spot, and more.


  • Utilizes different modes of action from two active ingredients for enhanced disease management.
  • Ideal for preventing and eliminating a wide range of lawn fungi with a single application, saving time and cost compared to using multiple products.
  • Safe for people and pets when used as directed.

Recommended usage:

  • Suitable for cool-season and warm-season lawns.
  • Apply in spring (May, June) and fall (October, November) for preventive disease control, adjusting application rates based on specific lawn disease conditions as per label instructions.
  • Best applied with a broadcast spreader on a dry lawn, followed by watering to move granules into the soil.

Why choose Headway® G?

  • Provides broad coverage against major lawn fungi, offering both preventive and curative benefits.
  • Simplifies lawn disease management with its easy-to-apply granular formulation.
  • Offers flexibility in application timing and rates to suit different lawn care needs throughout the season.

3. Caravan® G Fungicide and Insecticide in One 


Caravan® G combines azoxystrobin and thiamethoxam to control both lawn-damaging fungi and insects in one convenient application. It offers broad-spectrum control against diseases like red thread, brown patch and pests such as grubs, sod webworms, and chinch bugs.


  • Saves time and money by providing dual-action control with a single application.
  • Effective for season-long prevention of grubs and other lawn pests, along with a month of preventative large patch control.
  • Suitable for use on all grass types, including cool-season and warm-season lawns.

Recommended usage:

  • Apply Caravan® G between May and July for optimal control of lawn diseases and insects.
  • Use a broadcast spreader to apply on dry turf and water in with 1/4 inch of irrigation or rainfall within 48 hours.
  • For active fungus outbreaks, consider a follow-up application of Headway® G fungicide 28 days later.

Why choose Caravan® G?

  • Combines fungicide and insecticide capabilities into one product, reducing the need for separate applications.
  • Provides comprehensive protection against both fungi and pests, ensuring a healthy and resilient lawn throughout the season.
  • Easy-to-apply granular formulation with clear application instructions for effective use.

Fertilizers to Improve Soil Health

1. Golf Course Lawn (20-2-3) Liquid Fertilizer with Kelp and Fulvic Acid


Golf Course Lawn 20-2-3 is a custom-blended liquid fertilizer designed to produce a fast color response in all grass types. This product is ideal for those looking for an excellent liquid fertilizer that feeds your grass what it needs in a single application.


  • Fast green-up using 20% nitrogen, ideal for quick improvements in lawn appearance.
  • Contains micronutrients (Ca, Fe, Mg, Mn, Zn) for a more complete feeding package.
  • Includes seaweed extract and fulvic acid to improve soil quality and nutrient uptake.
  • Suitable for monthly or bi-monthly application to maintain the best lawn on your street.

Recommended usage:

  • Apply Golf Course Lawn 20-2-3 through foliar spray for best results.
  • Use a 4-gallon battery-powered sprayer with a TeeJet foliar spray tip.
  • Suitable for all grass types, including cool-season and warm-season lawns.
  • For cool-season lawns, apply in spring and fall. For warm-season lawns, apply from early spring through early fall.

Why choose Golf Course Lawn 20-2-3?

  • Provides a fast and effective green-up for a visually appealing lawn.
  • Offers a complete feeding solution with added micronutrients and soil enhancers.
  • Easy to apply and integrate with other lawn care products, ensuring consistent and vigorous turf growth.

2. Humic Max 16-0-8 - Lebanon Country Club Granular Fertilizer


Lebanon Humic Max 16-0-8 is a high-performance granular fertilizer designed for all grass types. It delivers a deep green color and enhanced turf health with its slow-release nitrogen and immediate potassium availability.


  • Contains 35% MESA slow-release nitrogen for fast green-up without excessive growth.
  • Includes 8% sulfate of potash for non-burning potassium that’s immediately available to the grass.
  • Features 8.9% humic acid, which acts as a biostimulant to improve soil health and nutrient uptake.

Recommended usage:

  • Apply at the rate of 3 lbs per 1000 square feet and water in for best results.
  • Suitable for use on cool-season lawns in spring and fall and warm-season lawns from early spring through early fall.
  • Use every 4-6 weeks during the growing season for optimal results.

Why choose Lebanon Humic Max?

  • Delivers sustained feeding with slow-release nitrogen and non-burning potassium.
  • Enhances soil health with humic acid, promoting better nutrient absorption and turf vigor.
  • Provides visible results within 5-7 days, making it one of the best fertilizers for maintaining a beautiful lawn.

3. Release 901C™ Biostimulant & Fertilizer 


Mirimichi Green Release 901C features premium micronized nutrients and carbon for optimized absorption, promoting rapid growth in soil biology and enhancing nutrient uptake. The 10% liquid carbon content drives deeper root growth and improves soil water retention.

Key Benefits:

  • Superior absorption: Small particle size makes nutrients immediately available.
  • Enhanced soil health: Liquid carbon creates soil aeration for deeper roots.
  • Versatile use: Acts as a catalyst for other turf maintenance products.

How to Use:

  • Application rate: 8 oz per 4,000 square feet using a backpack sprayer.
  • Timing: Apply during active growing months.
  • Watering: Ensure no rain is expected for 4-6 hours after application.

By incorporating these products into your lawn care routine, you can effectively prevent and manage red thread disease while promoting a healthier, more vibrant lawn. Visit our store to explore these top-quality products and achieve the lush, green lawn you desire.

Related: How to Read Fertilizer Numbers 

Give Red Thread the Red Card

When faced with red thread disease, swift identification and appropriate treatment are crucial. Utilizing recommended fungicides and other lawn care products tailored for disease management can effectively control the spread of the fungus and restore your lawn to its full potential.

Ready to tackle red thread disease and achieve a healthier lawn? Explore the Golf Course Lawn Store and follow expert tips on our YouTube Channel to get started today!