Understanding Lawn Fungicides: Types and Tips for Controlling Lawn Diseases

BY pure turf
January 25, 2024
Lawn Care

Maintaining a healthy and disease-free lawn is essential for homeowners who take pride in their outdoor spaces. One crucial element of lawn care is understanding the role of fungicides in disease prevention and control. In this blog post, we will explore the various types of lawn fungicides, provide tips for choosing the right one for your lawn, and discuss application techniques. By understanding lawn fungicides, homeowners can effectively tackle lawn diseases and enjoy a lush, vibrant lawn all year round.

Understanding Lawn Diseases

Common Lawn Diseases and Their Causes

  • Dollar Spot (Sclerotinia homeocarpa): Dollar spot is caused by a fungal pathogen and is characterized by small, circular patches of dead grass with tan-colored spots.
  • Brown Patch (Rhizoctonia solani): Brown patch is a fungal disease that causes irregularly shaped, brown patches in the grass, often surrounded by a dark, purplish ring.
  • Pythium Blight (Pythium spp.): Pythium blight is a common water mold disease that thrives in warm and wet conditions, leading to circular patches of blighted grass that appear water-soaked.

Identifying Symptoms of Fungal Diseases in Your Lawn

  • Discolored Patches: Fungal diseases often present as discolored patches in the grass, ranging from tan to brown or even yellow.
  • Irregular Patterns: Fungal diseases may exhibit irregular patterns, such as circular, spotty, or streaky patterns.
  • Thin or Dead Grass: Affected areas may have thin or dead grass, with patches that do not recover even with proper watering and fertilization.

The Impact of Fungal Infections on the Lawn's Health

  • Weakened Turf: Fungal infections weaken the grass, making it more susceptible to further damage from pests, drought, and other stressors.
  • Increased Weed Growth: Fungal infections create bare or thin areas in the lawn, providing an opportunity for weeds to invade and establish themselves.
  • Decreased Aesthetic Appeal: Fungal diseases can significantly impact the appearance of a lawn, making it look patchy, unhealthy, and unsightly.

By understanding common lawn diseases, identifying their symptoms, and recognizing their impact on a lawn's health, homeowners can take proactive measures to prevent and control these fungal infections.

Types of Lawn Fungicides

Contact Fungicides

Explanation of How Contact Fungicides Work

Contact fungicides work by forming a protective barrier on the surface of the plants, killing fungi upon direct contact. They can disrupt fungal cell membranes or interfere with key cellular processes, inhibiting their growth and reproduction.

Pros and Cons of Using Contact Fungicides


  • Quick Action: Contact fungicides provide immediate control upon application.
  • Broad Spectrum: They can target several types of fungi and diseases.
  • Low Resistance Potential: Fungi are less likely to develop resistance to contact fungicides compared to systemic ones.


  • Limited Residual Activity: Contact fungicides remain active on the foliage for a limited time and require regular reapplication.
  • Harmful to Beneficial Organisms: They can also harm beneficial insects and microorganisms present in the ecosystem.
  • No Internal Protection: Contact fungicides offer protection only on treated surfaces and are ineffective against systemic infections.

Systemic Fungicides

Explanation of How Systemic Fungicides Work

Systemic fungicides are absorbed by the plant and then transported through its tissues, reaching all parts of the plant, including new growth. They provide internal protection against fungal infections.

Pros and Cons of Using Systemic Fungicides


  • Long-Lasting Protection: Systemic fungicides can provide extended protection as they move within the plant.
  • Effective against Hidden Infections: They can reach and protect areas of the plant not directly exposed to the fungicide application.
  • Higher Efficacy: Systemic fungicides can address both existing infections and potential future infections.


  • Potential Toxicity Concerns: Some systemic fungicides may pose risks to humans, animals, or the environment. Appropriate precautions should be taken.
  • Higher Cost: Systemic fungicides are often more expensive than contact fungicides.
  • Potential for Resistance: Over reliance on systemic fungicides can promote the development of resistant fungal strains.

Preventive vs. Curative Fungicides

Differences Between Preventive and Curative Treatments

Preventive fungicides are applied before any signs of disease, usually based on risk factors like weather conditions or lawn history. The goal is to protect the plants from potential infections. Curative fungicides are used after symptoms appear to control and contain existing infections.

When to Use Each Type of Fungicide

Preventive fungicides:

  • Apply before the onset of favorable disease conditions, typically in early stages of growth or specific times of the year.
  • Useful in areas with a history of recurring diseases or in anticipation of expected disease outbreaks.

Curative fungicides:

  • Apply as soon as symptoms appear and are diagnosed as a specific disease.
  • Used to halt the progression of disease and prevent further damage.

Understanding the differences between preventive and curative fungicides enables homeowners to choose the appropriate treatment strategy for their lawn and effectively combat lawn diseases.

Choosing the Right Fungicide for Your Lawn

Assessing the Specific Lawn Disease

  • Identifying the Disease: Properly identifying the specific lawn disease is crucial for selecting the right fungicide. Look for symptoms such as discoloration, spotting, patchiness, or wilting of the grass blades.
  • Diagnostic Resources: Utilize diagnostic resources like online guides, extension services, or consult with a local lawn care professional to accurately identify the disease.
  • Fungicide Compatibility: Once identified, research which fungicides are known to be effective against the specific disease. Consider the active ingredients and mode of action.

Identifying the Type of Grass in Your Lawn

  • Grass Variety: Different grass varieties have varying levels of susceptibility to certain diseases. Identify what type of grass is present in your lawn (e.g., Bermuda grass, Kentucky bluegrass, etc.).
  • Fungicide Compatibility: Certain fungicides may be more effective or better tolerated by specific grass types. Research and consult product labels or professionals to ensure the fungicide is safe for use on your grass variety.

Environmental Considerations

  • Optimal Conditions: Some fungicides work best under certain environmental conditions. Consider the temperature, humidity levels, and expected rainfall during and after application.
  • Product Labels and Recommendations: Check the fungicide label for guidance on optimal environmental conditions for application and effectiveness.
  • Timing: Timing is critical for fungicide application to coincide with specific disease development stages or favorable environmental conditions.

Legal and Safety Considerations

  • Legal Requirements: Familiarize yourself with any legal requirements or restrictions related to fungicide use. Different areas may have regulations regarding application frequency, active ingredients, or licensing requirements.
  • Safety Precautions: Always prioritize safety when handling and applying fungicides. Read and follow all instructions, wear appropriate protective gear, and store and dispose of fungicides properly.
  • Consider Organic Options: If desired, explore organic fungicides or alternative, more environmentally friendly approaches to disease control.

By assessing the specific lawn disease, considering the grass type, accounting for environmental factors, and adhering to legal and safety guidelines, you can choose the right fungicide for your lawn and effectively prevent lawn diseases.

Application Tips

Proper Timing for Fungicide Application

  • Disease Life Cycles: Different diseases have varying life cycles and stages at which they are most susceptible to fungicide treatments. Apply fungicides at the appropriate stage in the disease cycle for maximum efficacy.
  • Weather Conditions: Weather conditions like humidity, temperature, and rainfall can also impact the effectiveness of fungicides. Apply fungicides when the weather is favorable for disease development.

Techniques for Uniform Coverage

  • Spraying Techniques: Use spraying equipment, such as backpack sprayers or hose-end sprayers, to achieve uniform coverage. Adjusting the nozzle and pressure can also help ensure an even application.
  • Calibrate Equipment: Calibrate the spraying equipment to ensure the right amount of product is applied to the lawn. This helps prevent under- or over-application of fungicides.
  • Overlapping Sprays: Overlap each spray pass by about 50% to ensure even coverage and prevent gaps.

Safety Precautions When Handling Fungicides

  • Protective Gear: Wear appropriate personal protective equipment like gloves, eye protection, and a respirator or face mask when handling fungicides to minimize potential exposure and health risks.
  • Storage and Disposal: Store and dispose of fungicides according to the product label instructions and any local regulations. Keep them out of reach of children and pets.

Dosage and Dilution Guidelines

  • Follow Product Instructions: Always read and follow the instruction label for the fungicide, including dosage and dilution guidelines.
  • Calculate Lawn Area: Determine the size of the lawn area to be treated and calculate the amount of fungicide needed accordingly.
  • Mix Properly: Use the correct ratio of water to fungicide to ensure proper dilution and avoid under- or over-application.

By applying fungicides at the appropriate time, using techniques for uniform coverage, taking safety precautions, and following dosage and dilution guidelines, homeowners can effectively prevent lawn disease.

Organic and Natural Alternatives

When it comes to keeping our lawns healthy and disease-free, fungicides play a crucial role in preventing and managing lawn diseases. While synthetic fungicides have long been the go-to solution, many homeowners are now seeking organic alternatives for a more sustainable approach. In this section, we will explore the world of organic fungicides, providing homeowners with information on natural options derived from plant extracts or beneficial microorganisms. 

Exploring Organic Fungicide Options

  • Plant Extracts: Organic fungicides derived from plant extracts, such as neem oil, garlic oil, or chamomile tea, can be effective against certain lawn diseases. These products work by disrupting the disease-causing organisms or boosting the plant's natural defenses.
  • Beneficial Microorganisms: Some organic fungicides contain beneficial microorganisms, like Bacillus subtilis or Trichoderma, which compete with and inhibit the growth of harmful fungi. They can provide long-term disease control and improve soil health.
  • Certified Organic Products: Look for fungicides that are certified organic by reputable organizations like the Organic Materials Review Institute (OMRI). These products meet organic standards and are free from synthetic chemicals.

Homemade Remedies for Fungal Disease Control

  • Baking Soda Spray: A mixture of baking soda, water, and liquid soap can help control fungal diseases like powdery mildew. This homemade fungicide works by changing the pH of the leaf surface, creating an unfavorable environment for the fungi.
  • Milk Spray: Diluted milk solutions can be used as a foliar spray to control certain lawn diseases. The proteins in milk have antifungal properties that can inhibit the growth of fungal pathogens.
  • Vinegar Solution: A solution of vinegar and water can be effective against certain fungal diseases. The acetic acid in vinegar can disrupt fungal cell membranes and inhibit their growth.

Pros and Cons of Organic Alternatives

Advantages of Organic Fungicides:

Organic fungicides are usually safer for the environment, beneficial insects, and pollinators. They can be used in organic gardening practices and are often more sustainable in the long term.

Limitations of Organic Fungicides:

Organic fungicides may have limited efficacy against certain diseases and may require more frequent applications compared to synthetic alternatives. They may also have a shorter shelf life and can be more expensive.

Integrated Approach: Organic fungicides can be used in combination with other cultural practices like proper watering, mowing, and proper soil health management to maximize disease control.

By exploring organic fungicide options, using homemade remedies when appropriate, and understanding the pros and cons of organic alternatives, homeowners have additional choices for preventing and managing lawn diseases in an environmentally friendly manner.

Preventative Lawn Care Practices

Preventing lawn diseases requires a proactive approach that goes beyond the use of fungicides alone. By implementing proper cultural practices and maintaining a healthy lawn, homeowners can significantly reduce the risk of fungal infections. In this section, we will explore a range of preventative lawn care practices that contribute to disease prevention and support overall lawn health. We will discuss the importance of cultural practices, proper lawn maintenance routines, and the role of aeration, watering, and soil management in disease prevention. By incorporating these practices into their lawn care routine, homeowners can create a resilient and disease-resistant turf.

Homeowner Practices to Reduce the Risk of Fungal Infections

Proper Mowing Height: Cutting the grass at the appropriate height promotes healthy growth and airflow, reducing the chances of fungal infections. Different grass species have specific height requirements, and maintaining the recommended height will help prevent disease.

Proper Watering Techniques: Overwatering or underwatering can create favorable conditions for fungal growth. Water deeply and infrequently, ensuring that the soil is adequately moist without becoming saturated. Watering in the morning allows the grass to dry before evening, preventing prolonged leaf wetness.

Soil Management: Well-drained soil with proper pH levels promotes a healthy lawn and minimizes the risk of fungal infections. Aerating the soil and addressing any compaction issues improves air circulation and water penetration, reducing disease risks.

Proper Lawn Maintenance Routines

Mowing Practices: Use sharp blades to ensure clean cuts and avoid stressing the grass, which can make it more susceptible to diseases. Regularly remove no more than one-third of the grass blade height to maintain a healthy lawn.

Watering Practices: Water deeply and infrequently, providing about 1 inch of water per week, including rainfall. This encourages deep root growth and helps the grass withstand drought stress and fungal infections.

Fertilization: Apply the proper type and amount of fertilizer according to the specific needs of your lawn. Balanced nutrition promotes strong, disease-resistant turf. Understand more of the importance of fertilization on our blog here.

Aeration: Aerating the soil relieves compaction and allows for better water and nutrient penetration, reducing the risk of diseases such as brown patch.

Aeration, Watering, and Soil Management for Disease Prevention

Aeration: By mechanically removing small plugs of soil, aeration improves root development, enhances air exchange, and reduces soil compaction. This helps prevent disease-causing organisms from taking hold in the lawn. Understand more of the importance of aeration and seeding on our blog here.

Watering Practices: Water deeply but infrequently to encourage strong root growth and reduce surface moisture, which can promote disease development. Water in the early morning to allow the grass to dry during the day.

Soil Management: Regularly test the soil's pH and nutrient levels to ensure optimal growing conditions. Adjust the pH if needed and provide necessary nutrients to support healthy turf. Proper soil preparation and maintenance are essential for a disease-resistant lawn.

By implementing these preventative lawn care practices, homeowners can create an environment that is less favorable for disease-causing organisms, resulting in a healthier and more resilient lawn.

Common Mistakes to Avoid

Using fungicides can be an effective way to manage and prevent lawn diseases. However, to maximize their effectiveness, it is important to avoid common mistakes that can hinder their performance. In this section, we will highlight some of the common mistakes homeowners make when using fungicides and provide guidance on how to avoid them. We will discuss improper application techniques, the use of outdated products, and the neglect of environmental factors. Additionally, we will explore the importance of recognizing and correcting application errors promptly. Finally, we will emphasize the importance of implementing long-term strategies to enhance lawn health and resilience, reducing the reliance on fungicides altogether.

Mistakes That Can Hinder the Effectiveness of Fungicides

  • Improper Application: Applying fungicides incorrectly can result in inadequate coverage or wastage, reducing their effectiveness. It is important to follow the instructions on the product label, including the dosage, timing, and application technique.
  • Using Outdated Products: Fungicides have limited shelf lives and can lose their effectiveness over time. Check the expiration dates and ensure that you are using fresh and potent products for optimal results.
  • Neglecting Environmental Factors: Environmental conditions can have a significant impact on the effectiveness of fungicides. Factors such as temperature, humidity, and rainfall can affect the efficacy of the treatment. Consider the weather conditions and apply fungicides when they are most likely to be effective.

Recognizing and Correcting Application Errors

  • Inadequate Coverage: Failing to apply fungicides uniformly and covering the entire affected area can result in patchy disease control. Ensure proper spray or spreader calibration and apply the product evenly to achieve consistent coverage.
  • Incorrect Timing: Timing is critical when applying fungicides. Apply them when conditions are conducive to disease development or at the early signs of disease symptoms. Applying fungicides too late may result in limited effectiveness.
  • Mixing or Dilution Errors: It is important to mix or dilute fungicides according to the manufacturer's instructions. Using incorrect ratios or failing to thoroughly mix the product can lead to inconsistent or ineffective applications.

Long-Term Strategies for Disease Prevention

Proper Lawn Maintenance: A healthy and well-maintained lawn is less susceptible to diseases. Implement proper cultural practices like regular mowing, adequate watering, and appropriate fertilization to strengthen the turf and minimize disease risks.

Disease-Resistant Grass Varieties: Choosing grass varieties that have natural resistance to common diseases can significantly reduce the need for fungicide applications. Research and select grass types that are resistant to prevalent diseases in your region.

Good Air Circulation: Proper airflow within the lawn helps to reduce the humidity levels and prevents the conditions that favor disease development. Regularly remove thatch and ensure proper spacing between plants to promote air circulation.

By avoiding common mistakes in fungicide application, promptly addressing application errors, and implementing long-term strategies for disease prevention, homeowners can effectively manage lawn diseases and maintain a healthy and vibrant lawn.

Frequently Asked Questions

Lawn fungicides can be a valuable tool in preventing and managing lawn diseases. However, homeowners may have questions and concerns about their proper use, effectiveness, safety, and environmental impact. In this section, we will address commonly asked questions and provide guidance and solutions for homeowners' concerns.

When should I use fungicides on my lawn?

Fungicides should be applied preventively, before disease symptoms appear or when conditions favor disease development. Consult local extension offices or lawn care professionals for guidance on the optimal timing for fungicide applications in your area.

How often should I apply fungicides?

The frequency of fungicide applications depends on the specific disease and the product being used. Follow the instructions on the product label for recommended application intervals. In some cases, a recurring schedule may be necessary to prevent disease outbreaks.

Are fungicides safe for use in residential areas?

Fungicides that are labeled for use on lawns undergo thorough testing to ensure their safety when used according to the instructions. However, it is important to follow the label directions carefully to minimize potential risks. Keep children and pets off treated areas until the product has dried.

Will fungicides harm beneficial insects or pollinators?

When used correctly and according to the label instructions, fungicides pose minimal threats to beneficial insects or pollinators. To further minimize potential impacts, avoid treating blooming flowers and be cautious when spraying near flowering plants.

Is it possible to become resistant to fungicides?

Fungicide resistance can occur when repeated use of the same product leads to the development of resistant strains of fungi. To reduce the risk of resistance, it is important to rotate between different fungicide classes with different modes of action.

Are there alternatives to chemical fungicides?

Yes, there are alternative methods for managing and preventing lawn diseases. These include implementing good cultural practices, using disease-resistant grass varieties, improving soil health, and promoting a balanced ecosystem through proper lawn maintenance. However, in some cases, chemical fungicides may be necessary for effective disease control.

What can I do to minimize the environmental impact of fungicides?

To minimize the environmental impact of fungicides, follow the product instructions carefully, avoid overusing or overapplying the product, and consider using environmentally friendly fungicides, if available. Properly dispose of any excess products or containers according to local regulations.


Throughout this blog post, we have explored important aspects of lawn fungicides for disease prevention and control. We have discussed common mistakes to avoid, such as improper application techniques, using outdated products, and neglecting environmental factors. Recognizing and correcting application errors promptly is crucial for maximizing the effectiveness of fungicides. Additionally, we have emphasized the importance of implementing long-term strategies, such as proper lawn maintenance and the use of disease-resistant grass varieties, to enhance lawn health and reduce reliance on fungicides.

Encouraging Proactive Lawn Care to Prevent Fungal Diseases

To maintain a healthy and disease-free lawn, proactive lawn care practices are essential. Regular mowing, proper watering, and appropriate fertilization help strengthen the turf and reduce the risk of disease. Good air circulation and timely removal of thatch also play a vital role in disease prevention. When necessary, timely and targeted fungicide applications can provide an extra layer of protection.

Additional Resources

For readers seeking more information on lawn fungicides and disease control, here are some helpful resources:

  • Local extension offices often provide guidance on lawn diseases and fungicide recommendations specific to your area.
  • The Environmental Protection Agency (EPA) provides regulatory information and resources on pesticide safety, including fungicides.
  • Professional lawn care associations and organizations, like the National Association of Landscape Professionals (NALP), may have resources and guidance on fungicide use in lawn care.
  • At Pure Turf, Fungicide is included in all of our lawn care residential programs. We’ve seen a massive difference in quality with fungicide applications from May-September. The retired standard program did not include fungicide applications and we saw quite a few lawns get decimated by disease in summer months. Even lawns with mild to moderate disease pressure dealt with more weeds due to the thinning turf canopy caused by disease. 

When you sign up for our Premium or Elite program, you will also receive:

  • A Disease free guarantee - If you have active disease at any point during the year we’ll do additional fungicide applications at no charge. 
  • An Insect damage guarantee - If your lawn suffers insect damage at any time we’ll apply an additional insect control at no charge. 
  • An annual August client meeting - This is our favorite addition to these programs…. This optional meeting will be available for you to schedule with us to discuss your lawn in detail, in person each and every August. This way we can better get to know you and what your priorities are when it comes to your lawn. And if there is anything we can do to improve your lawn while we are there (specialty weed control, fungicide, etc) we’ll do it. For free.

How Pure Turf Can Help 

We hope you found this blog helpful and feel empowered for confident, all-season lawn care! 

If you enjoyed this blog, you may also enjoy the following: 

At Pure Turf, we offer a selection of lawn care programs that include 

  • Fertilization and weed control 
  • Aeration and seeding 
  • Disease treatment and prevention 
  • Soil health 
  • Mosquito control 
  • And more!

Get a plan tailored to your needs by contacting us for a free estimate today! 

We look forward to hearing from you!

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