How to Prevent and Get Rid of Large Patch Disease in Your Lawn

Large patch disease (LPD), scientifically known as Rhizoctonia solani, is a prevalent fungal disease affecting warm-season grasses. This disease manifests as circular or irregularly shaped patches of discolored, dying grass, typically ranging from a few inches to several feet in diameter. 

Understanding the characteristics and conditions contributing to the development of large patch disease is essential for effective prevention and treatment.

Identifying Large Patch Disease

Large patch disease primarily affects warm-season grasses such as St. Augustinegrass, Bermudagrass, Centipedegrass, and Zoysiagrass. The disease begins as small, water-soaked lesions on the leaf sheaths near the soil surface. As the fungus progresses, these lesions enlarge and cause the grass to turn yellow or brown, eventually resulting in large, irregular patches of dead grass. The patches can merge, creating extensive areas of damage.

Conditions That Favor Large Patch Disease

Large patch disease thrives in specific environmental conditions that promote fungal growth. The primary factors that contribute to the development of large patch disease include:

• Excessive moisture: Prolonged periods of wet or damp conditions provide an ideal environment for the fungus to grow and spread. Overwatering, poor drainage, and heavy rainfall can all lead to excessive moisture levels in the soil.
• Poor drainage: Lawns with compacted soil or areas with poor drainage are more susceptible to large patch disease. Standing water and slow-draining soils create conditions where the fungus can thrive.
• High humidity: Humid conditions, especially during the fall and spring, favor the growth of Rhizoctonia solani. Warm days followed by cool nights create a conducive environment for the fungus.
• Temperature fluctuations: large patch disease is most active during periods of fluctuating temperatures, particularly when daytime temperatures are warm and nighttime temperatures are cool. This is why the disease is commonly observed in the fall and spring.

By understanding the nature of large patch disease and the conditions that promote its development, lawn care enthusiasts can take proactive measures to prevent and manage this common fungal disease. 

Preventive Measures

Preventing large patch disease is essential for maintaining a healthy and attractive lawn. By adopting proper lawn care practices and creating an environment that discourages fungal growth, you can significantly reduce the risk of large patch disease. Here are some effective preventive measures:

Proper Lawn Maintenance

Mowing:

• Keep grass at the recommended height: Different grass types have specific mowing height recommendations. Keeping your grass at the correct height helps it develop a strong root system and stay healthy. For example, Bermuda grass should be maintained at 0.75 - 2 inches, while St. Augustine grass should be kept at 2.5 - 4 inches.
  
  
• Regular Mowing: Mow your lawn regularly to avoid excessive thatch buildup, which can retain moisture and create favorable conditions for fungi.

Watering:

• Water deeply but infrequently: Water your lawn deeply, providing about 1 inch of water per week, and allow the soil to dry out between watering sessions. This encourages deep root growth and reduces the constant moisture that fungi thrive on.
• Avoid overwatering: Overwatering can lead to waterlogged soil and promote fungal growth. Ensure your lawn has proper drainage to prevent standing water.

Aeration:

• Improve soil drainage: Aerate your lawn at least once a year to alleviate soil compaction and improve water penetration. Aeration enhances root growth and reduces the risk of fungal diseases.
• Reduce thatch: Thatch, a layer of dead grass and roots, can harbor fungi. Aeration helps break down thatch and promotes a healthier lawn. Or you can scalp your lawn at the start of the season to eliminate all the dead grass before your lawn comes out of dormancy.

Fertilization

Use Balanced Fertilizers:

• Promote healthy grass growth: Apply a balanced fertilizer that provides essential nutrients like nitrogen, phosphorus, and potassium. Healthy grass is more resistant to diseases, including large patch disease.
• Avoid over-fertilizing: Excessive nitrogen can promote lush, weak growth that is more susceptible to fungal infections. 

Timing of Fertilization:

• Spring and fall applications: Fertilize your lawn in the spring and fall when grass is actively growing. Avoid late-season fertilization, which can stimulate excessive growth and increase susceptibility to large patch disease.

By following these preventive measures, you can create a robust defense against large patch disease and maintain a healthy, vibrant lawn.

Identifying Large Patch Disease Early

Early identification of large patch disease is crucial for effective treatment and prevention of further damage. By regularly inspecting your lawn and being aware of the early signs, you can address the issue before it spreads. Here’s how to identify large patch disease early:

Regular Lawn Inspections

Conduct Frequent Inspections:

• Routine checks: Inspect your lawn regularly, especially during the fall and spring when large patch disease is most likely to occur. Walk through your lawn every few weeks, looking for any signs of distress.
• Inspect vulnerable areas: Pay special attention to areas with poor drainage, excessive moisture, or shade, as these conditions are conducive to fungal growth.

Recognize Early Signs:

• Small, water-soaked lesions: The first sign of large patch disease often appears as small, water-soaked lesions on the leaf sheaths near the soil surface. These lesions can be difficult to spot, so close inspection is necessary.
• Yellowing grass: Early stages of large patch disease may cause the grass to turn yellow in small, irregular patches. These patches may enlarge and merge over time, forming larger areas of affected grass.

Recognizing Advanced Symptoms

Advanced Patches:

• Brown or dead grass: As large patch disease progresses, the yellow patches may turn brown or even die. The affected areas can expand rapidly, especially under favorable conditions for the fungus.
• Irregular shapes: The patches often have irregular shapes and can be several feet in diameter. The edges of the patches may appear reddish-brown, further indicating fungal activity.

Thatch Layer Examination:

• Inspect thatch: Check the thatch layer (the layer of dead grass and roots) for signs of fungal activity. Fungal mycelium, which appears as a white or light-colored thread-like structure, may be visible within the thatch layer.

By conducting regular lawn inspections, monitoring weather and soil conditions, and recognizing the early signs of large patch disease, you can take swift action to manage and treat the disease. 

Related: How to Get Rid of Brown Patch Fungus on Your Lawn

Treatment Options

Recommended Products to Combat Large Patch Disease

To effectively combat large patch disease in your lawn, it is essential to choose high-quality fungicides that are specifically formulated to treat and prevent fungal infections.

1. Pillar SC Fungicide — Liquid Brown Patch and Dollar Spot Control

pillar-sc-fungicide-liquid-brown-patch-and-dollar-spot-control

Pillar SC Fungicide is a powerful liquid formulation designed to control various lawn diseases, including large patch. It combines two active ingredients, pyraclostrobin, and triticonazole, which work together to provide broad-spectrum disease control. This fungicide is easy to apply and provides long-lasting protection on all types of grass, both warm and cool-season.

Application Tips: 

• Apply Pillar SC Fungicide as a preventive treatment in the fall and as early as April or May in the spring or at the first sign of disease. 
• Use a battery-powered 4-gallon sprayer with a large droplet nozzle to apply the fungicide to your lawn.
• If your focus is controlling an existing lawn disease, we recommend a second application of Pillar SC 14 - 21 days after the initial application.
• Apply 1/4" of water from irrigation or rainfall to move Pillar SC into the soil after application.

2. Headway G — Granular Fungicide

headway-g-fungicide-granular

Headway G Fungicide is a granular product that combines the effectiveness of azoxystrobin and propiconazole, offering broad-spectrum control of numerous lawn diseases, including large patch. The granular form makes it easy to apply and ensures even distribution across your lawn.

Application Tips: 

• For best results, apply Headway G Fungicide evenly across the lawn using a broadcast spreader. 
• Water the lawn lightly after application to activate the fungicide. 
• Apply in spring (May, June) and fall (October, November) to prevent lawn diseases.
• In situations where you're dealing with an active fungus outbreak, we recommend a follow-up application of Headway G fungicide 28 days later.

3. Caravan G Insecticide and Fungicide

caravan-g-insecticide-and-fungicide 

Caravan G Insecticide and Fungicide combines the benefits of both an insecticide and a fungicide in one granular formulation. It controls a wide range of pests and diseases, including large patch, making it an excellent choice for comprehensive lawn care. The active ingredients include azoxystrobin for disease control and thiamethoxam for insect control. It is safe to use on all grass types.

Application Tips: 

• Apply Caravan G evenly using a broadcast spreader, ensuring thorough coverage of the lawn. 
• Water the lawn lightly after application to activate the product. This dual-action formula is ideal for integrated pest and disease management.

Additional Tips for Using Fungicides

• Timing: Apply fungicides preventively in the fall and spring when conditions are favorable for large patch development. Early treatment can prevent the disease from establishing and spreading.
• Application Rates: Always follow the manufacturer's instructions for application rates and intervals. Overapplication can harm your lawn and the environment, while underapplication may not provide effective control.
• Safety: Wear protective clothing, gloves, and a mask when handling and applying fungicides. Ensure that pets and children stay off the treated lawn until the product has dried completely.

By incorporating these recommended fungicides into your lawn care routine, you can effectively manage and prevent large patch disease, ensuring a healthy and vibrant lawn year-round.

Related: The Most Effective Fungicides to Use on Your Lawn

Using Biostimulants to Prevent Large Patch Disease

Biostimulants are substances that enhance the natural processes in plants and soil to improve overall health, resilience, and growth. Incorporating biostimulants into your lawn care routine can be an effective strategy to prevent large patch disease by strengthening your grass and improving soil health. Here’s how you can use biostimulants to prevent large patch:

Types of Biostimulants

Humic and Fulvic Acids

• Function: Improve soil structure, increase nutrient uptake, and stimulate root growth.
• Application: Apply humic and fulvic acid products to your lawn to enhance soil health and boost the grass’s natural defenses against diseases.

Seaweed Extracts

• Function: Provide essential micronutrients, stimulate growth, and increase stress tolerance.
• Application: Use seaweed extract foliar sprays or soil drenches to strengthen your lawn and make it more resistant to fungal infections like large patch.

Beneficial Microorganisms

• Function: Improve soil microbiology, enhance nutrient cycling, and outcompete pathogenic fungi.
• Application: Introduce beneficial microorganisms, such as mycorrhizal fungi and beneficial bacteria, to the soil to create a healthy microbial environment that suppresses harmful pathogens.

Recommended Fertilizers and Biostimulants for the Prevention of Lawn Diseases

Using biostimulants and high-quality fertilizers can significantly enhance your lawn’s health and resilience, making it less susceptible to large patch disease. Here are five recommended products.

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

Our very own Golf Course Lawn 20-2-3 Liquid Fertilizer provides a balanced nutrient ratio of 20-2-3 (N-P-K) along with kelp and fulvic acid. Kelp is a natural biostimulant that promotes root growth and stress tolerance, while fulvic acid enhances nutrient uptake.

Application Tips: 

• For warm-season lawns, apply this fertilizer throughout the growing season to support healthy, vigorous grass growth. For cool-season grass, apply in the spring and the fall when your lawn is in growth mode.
• It is an ideal product for foliar spoon-feeding.
• No need to water in. Simply spray and go on with your day!
• Apply monthly or every two weeks for the best lawn in your neighborhood.
• Use a battery-powered 4-gallon sprayer with TeeJet foliar spray tip to apply.
• Safe for cool and warm-season lawns.

2. Golf Course Lawn Micronutrient Liquid Fertilizer with 2% Iron

Our Golf Course Lawn Micronutrient Liquid Fertilizer provides essential micronutrients, including iron, manganese, and zinc, which are crucial for maintaining healthy grass. Adequate micronutrient levels improve disease resistance and overall lawn health. It delivers the "hard to find" nutrients your lawn needs for a deep green color. It also enhances the performance of other liquid fertilizers like Release 901C.

Application Tips: 

• Use this micronutrient fertilizer as a supplement to your regular fertilization program. 
• We recommend applying Golf Course Lawn Micronutrient through foliar spray. It can be applied alone or in a tank mixed with other products without any adverse interactions.
• It does not require watering in as it works via foliar uptake.
• Safe for warm and cool-season lawns.

3. Release 901C™

Release 901C™ is a liquid biostimulant that combines nitrogen with organic compounds to promote healthy growth and stress tolerance. It is designed to enhance root development and overall plant vigor. This fertilizer and biostimulant combo sports 9% nitrogen and 1% potassium for a vibrant lawn, plus 10% liquid carbon and micronutrients to boost soil biology.

Application Tips: 

• Apply Release 901C™ regularly during the growing season to boost your lawn’s resilience. 
• Use a battery-powered 4-gallon sprayer with TeeJet foliar spray tip to apply.
• No need to water it in.
• Safe for cool and warm-season lawns.

4. Release Zero

Release ZERO is a liquid carbon-based biostimulant that improves soil health and nutrient availability. It contains no added nutrients, making it ideal for use with your existing fertilization program. Release ZERO mixes easily with fertilizer, herbicides, and pesticides to improve their performance. The 10% liquid carbon in Release ZERO creates aeration within the soil to drive deeper root growth. This improves soil water retention and boosts nutrient uptake.

Application Tips: 

• Use Release ZERO to enhance soil microbial activity and nutrient uptake. 
• Use a battery-powered 4-gallon sprayer with TeeJet foliar spray tip to apply.
• Safe for cool and warm-season lawns.

5. Essential G™ Granular Carbon

Essential G™ Granular Carbon is a granular soil amendment that consists of reclaimed coffee grounds, premium organics, humate, biochar, and silicon. It contains natural, reclaimed waste stream inputs to improve the soil. It increases soil organic material allowing the soil to hold nutrients and moisture. It improves soil structure, promotes beneficial microbial activity, and enhances nutrient retention and availability. 

Application Tips: 

• Spread Essential G™ evenly across your lawn using a broadcast spreader. 
• Incorporate it into your soil management practices to improve soil health and support disease-resistant grass.
• It can be applied anytime throughout the year as long as the ground isn't frozen.
• Safe for cool and warm-season lawns.

Benefits of Using Biostimulants

Improved Nutrient Uptake:

• Enhanced growth: Products containing fulvic acid, kelp, and micronutrients improve the grass’s ability to absorb essential nutrients, leading to healthier and more vigorous growth.
• Balanced nutrition: Regular use of these fertilizers ensures your lawn receives a balanced supply of macronutrients and micronutrients necessary for optimal health.

Enhanced Soil Health:

• Microbial activity: Biostimulants like Release Zero and Essential-G™ promote beneficial microbial activity in the soil, which can outcompete pathogenic fungi and reduce the risk of large patch.
• Soil structure: Improved soil structure enhances root development and water infiltration, creating a more resilient lawn.

Increased Disease Resistance:

• Stronger plants: Healthier grass with strong root systems and adequate nutrition is naturally more resistant to diseases, including large patch.
• Stress tolerance: Biostimulants help the grass tolerate environmental stresses, reducing the likelihood of disease outbreaks.

By integrating these recommended products into your lawn care routine, you can create a robust and healthy lawn that is less susceptible to large patch disease. Regular application of these biostimulants and fertilizers will ensure your grass remains vibrant and resilient year-round.

Related: What Is a Lawn Biostimulant and Why Are They Important?

Patch Up Your Lawn

The key to preventing large patch disease lies in consistent and comprehensive lawn care. Regular monitoring, proper mowing, adequate watering, and timely application of nutrients and biostimulants will ensure your lawn remains lush and disease-free.

Are you ready to take your lawn to the next level? Visit our store to explore our wide range of high-quality lawn care products, including fungicides, fertilizers, and biostimulants.