Common Lawn Diseases: Types, Treatment, and Prevention

Common Lawn Diseases: Types, Treatment, and Prevention

A lush green lawn is a source of pride for many homeowners. However, a variety of factors can lead to the development of lawn diseases, which can turn vibrant greens into a patchwork of yellow, brown, and dying grass. Understanding common lawn diseases, their causes, symptoms, and proper treatments is critical to maintaining a healthy and attractive lawn. In this article, we will explore the most prevalent types of lawn diseases and discuss effective measures to treat and prevent their occurrence.

Common Types of Lawn Diseases

Brown Patch (Rhynchosporium)

Brown patch is a fungal disease that affects cool-season grasses and is particularly harmful to Kentucky early grass and Tall fescue. It thrives in warm, moist conditions and is usually prevalent in the summer. Affected areas show round or irregular brown patches of dead grass.

How to Control the Brown Patches?

Proper lawn care practices, such as adequate watering, proper mowing height, and good soil drainage, can help prevent brown patches. In severe cases, fungicides may be needed.

Dollar Spot (Sclerotinia Homeocarpa)

Dollar spot is a common fungal disease that usually occurs in nitrogen-deficient lawns and environments with prolonged wet foliage. The disease usually manifests itself as small patches of dead or bleached grass the size of a silver dollar on the lawn that slowly swells into larger, irregularly shaped areas. Infected leaves will also develop tan or straw-colored spots.

How to Control the Dollar Spot?

The use of fungicides with [propiconazole], a common active ingredient, combined with proper fertilization and watering techniques can help control and prevent dollar spot disease. Also, stop disease development by improving soil drainage, reducing shade, and pruning regularly.

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Powdery Mildew (Powdery Mildew Fungus)

Powdery mildew is a fungal disease commonly found on a variety of plants. It is particularly common on cool-season grass species such as Kentucky Early Grass. This disease is primarily found in moist, shady areas and is more prevalent on lawns with poor air circulation and low light levels. Powdery mildew usually appears as a powdery, white, or light gray coating on grass leaves, often accompanied by stunted growth and leaf curl.

How to Controll the Powdery Mildew?

Maintenance measures such as regular mowing, deep and infrequent watering, and aeration of the lawn can help prevent powdery mildew. Severe infestations may require a fungicide (Myclobutanil), can inhibit the growth of mildew. Make sure to consult your garden center for advice and use it with caution.

Pythium aphanidermatum (Rot Fungus)

Pythium aphanidermatum occurs most often in hot and humid weather, and its development is promoted by prolonged heat and humidity from early summer to autumn. Overwatering, excessive thatching, and poor soil drainage can spread the disease. The disease usually manifests itself as greasy, irregular patches that rapidly grow larger, and the lawn turns brown and dies. It can also be accompanied by white fluffy fungal growth in wet conditions.

How to Control the Pythium?

Improve soil drainage and aeration, reduce thatch build-up, avoid overwatering, use high levels of nitrogen with caution, and avoid mowing in hot, humid weather. If the disease has started to spread, using a fungicide with [Methomyl-M] can effectively control its further spread.

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How to Treat and Prevent Lawn Diseases

Lawn Care

  • Mowing: Maintain a mowing height appropriate for your grass type and avoid cutting more than 1/3 of the grass blades in a single mowing session. This will reduce stress on your lawn and promote healthy growth.
  • Fertilization: Apply the right amount and type of fertilizer for your lawn's needs. A balanced supply of nutrients strengthens the grass and increases its natural resistance to disease.
  • Aeration:Regular aeration of your lawn improves water and nutrient uptake and prevents thatch buildup, which can help inhibit disease development.

Proper Irrigation

  • Watering Schedule: Water your lawn early in the morning to allow grass blades to dry throughout the day. Avoid evening or nighttime watering, as prolonged moisture on the lawn can promote fungal growth.
  • Watering depth:Be sure to provide enough water to penetrate the soil to a depth of 6-8 inches. This will promote deep-root growth and help the grass resist drought and disease stress.
  • Watering Techniques:Use sprinklers or irrigation systems to provide an even water supply and avoid excessive runoff. Deep and infrequent watering is more beneficial than frequent shallow watering. RainPoint automatic sprinklers allow you to set the amount and frequency of watering, saving up to 20% of water compared to traditional sprinklers and further optimizing water management.
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Soil Health and Maintenance

  • Soil testing: Soil tests are conducted regularly to assess nutrient levels and pH levels. Most lawns are adapted to pH levels between 6.0 and 7.0, and using soil amendments to properly adjust pH levels helps maintain a healthy lawn.
  • Thatch Management:Periodically remove excessive thatch buildup by raking. Excessive thatch harbors disease-causing organisms and prevent proper air and water movement in the soil.
  • Replanting:Periodically replant your lawn with disease-resistant grass varieties to fill in bare spots and strengthen the overall lawn to make it more resistant to disease.

Disease-resistant grass varieties

  • Choose wisely:When building or renovating a lawn, select grass varieties known for their disease resistance in your area. Consult your local turf specialist or extension service to determine the best choice.
  • Proper seeding: Ensure proper seed-to-soil contact during seeding and follow the recommended seeding rate. Adequate seed cover will help establish a lush, healthy lawn that is resistant to disease invasion.


  • Fungicides should be used as a last resort when cultural practices alone are not effective in controlling or preventing lawn diseases.
  • If fungicides are needed, use them at the appropriate time to target specific diseases according to the manufacturer's instructions. Early treatment or preventive applications are usually more effective than curative measures.


Remember, catching and acting quickly before it's too late is the key to effectively treating turf diseases and minimizing their impact. By understanding the common types of lawn diseases and taking preventive measures, you can create a thriving, resilient lawn that will be the envy of those around you.

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