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Pythium Blight

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Pythium Blight Disease Identification Guide

Pythium Blight: A Fungal Turf Disease

Pythium blight, also known as grease spot or cottony blight, is a fungal infection that can affect all turfgrass types, with the most significant damage occurring in cool-season grasses. This disease can spread easily through people, equipment, animals, or by water over short distances.

Initially, affected areas on your lawn may not appear as overtly infected. Grassy patches infested with Pythium blight might just look like dark, damp spots. As the disease progresses, these damp areas develop a greasy look, with the infected grass blades flattening and sticking together.

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Pythium Blight Appearance

Signs and Symptoms of Pythium Blight

When Pythium blight affects turfgrass, the overall health of the grass declines. Here are some common symptoms to look out for:

  • Irregular patches or streaks of damaged turf
  • Small, unhealthy areas of grass may merge into larger patches
  • Dark, water-soaked lesions appear on individual grass blades
  • Grass blades first turn yellow and then progress to light brown as they die
  • Irregularly shaped, dark, greasy patches of matted grass, sometimes spanning 6 to 12 inches in size
  • A cottony, white fungal growth may appear on affected grass when morning dew is present. These patches may resemble pink snow mold, but it’s important to distinguish between the two diseases to ensure proper treatment. Treating the wrong disease could cause additional turf damage.

If you suspect your lawn is affected by Pythium blight, check our Pythium Blight Inspection Guide to learn where to look for it on your property. Click the right arrow below to continue reading.

Pythium Blight Disease Inspection Guide

How to Inspect for Lawn Diseases
To effectively treat Pythium blight, it is essential to identify the early signs of this fungal disease in your lawn. Recognizing these symptoms will allow you to act quickly and apply the correct treatment.

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Step1 Where Does Pythium Blight Occur?

The pathogen responsible for Pythium blight can survive in plant debris, soil, and water, as well as within the infected plants. The spores of Pythium are easily transported, making this disease capable of affecting any type of turfgrass that experiences sufficient moisture.

Though Pythium blight can impact all grass types, it tends to be more damaging to cool-season grasses, especially ryegrass, which is often used in overseeding for bermudagrass.

Step2 When Does Pythium Blight Occur?

Pythium blight can affect your lawn at any point during the active growing season, but it is most prevalent during hot, humid weather. Ideal conditions for Pythium blight are daytime temperatures in the 80s or 90s, combined with humidity levels exceeding 90%. In these conditions, large areas of your lawn could be damaged by blight within just 48 hours.

Grassy areas that have been recently seeded or overseeded are especially vulnerable to Pythium blight in warm, humid conditions.

If you're uncertain whether you have Pythium blight or another turf disease, you can reach out to your local extension office. A master gardener or volunteer can help identify the disease affecting your lawn.

Step3 What Causes Pythium Blight to Grow?

Pythium blight thrives in dense, alkaline soils with high nitrogen levels, which encourage the growth of this disease. To understand how soil pH influences plant and fungal growth, consult our Soil pH guide.

Conditions that contribute to the growth of Pythium blight include a layer of thatch, compacted soil, and poor drainage leading to standing water. Proper lawn maintenance and keeping the lawn healthy are essential in preventing the growth of this disease.

Pythium Blight Disease Treatment Guide

Steps to Control Pythium Blight Lawn Disease

Pythium blight can affect various types of turfgrass, but it is most damaging to cool-season grasses. If your lawn is in this category, it's important to stay vigilant for signs of fungal diseases.

This unattractive lawn disease can spread quickly under favorable conditions. Being proactive in treating your lawn for Pythium blight will minimize the damage caused by this fungal infection.

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Step1 Apply Fungicide Promptly

Lawn Disease Treatment and Control
Choose and apply a fungicide labeled to control Pythium blight.

At the first sign of the disease, apply the fungicide to stop its spread.
Be sure to follow the product’s label carefully to understand the correct application method and frequency.

Products we recommend for Step 1

Step2 Rotate Fungicides Regularly

Certain fungicides can lead to resistance in your lawn. Check the product label to understand how often to rotate fungicides to prevent resistance buildup.
Rotate the active ingredients in the fungicide products you use for treating this disease. Use the Mode of Action chart on the product packaging to choose effective rotations. For more guidance on fungicide rotation, check out our fungicide guide.

Apply fungicides as needed and limit applications to avoid overuse, which can reduce resistance.
Combining fungicide treatments with proper lawn care practices not only cuts down on fungicide use but also helps prevent future disease outbreaks, limiting exposure to fungicides.

By following these tips and using the right products from Pest Control Spuerstore, you can effectively manage Pythium blight and other fungal lawn diseases. Contact us via phone or chat if you have any questions.

Pythium Blight Disease Prevention Guide

Prevent Pythium Blight by Maintaining a Healthy Lawn

Preventing fungal diseases like Pythium blight from affecting your lawn should be a priority each year. Keeping your lawn healthy and free from stress is crucial in protecting it from fungal turf diseases. Preventing Pythium blight involves a few key steps, which we will detail below.

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Step1 Ensure Proper Fertilization

High nitrogen levels in the soil can promote Pythium blight in certain types of turf. It's important to factor in your soil's nutrient levels, local climate, and grass variety when determining how best to fertilize your lawn. Following a lawn care schedule tailored to your specific property ensures that your lawn gets the right amount of nitrogen and other essential nutrients. A properly nourished lawn is better equipped to withstand Pythium blight and other lawn diseases.

You can also test your lawn with a home soil test kit to assess its nutrient levels. With the test results, you can select the appropriate fertilizer to help your lawn thrive and better defend against fungal diseases like Pythium blight.

Step2 Minimize Conditions Favorable to Pythium Blight

Pythium blight thrives in warm, damp conditions. To reduce the likelihood of this disease, it's important to minimize those conditions.

  • Water your lawn early in the morning, before sunrise, to allow the sun to help dry the grass quickly and limit the time the lawn remains wet.
  • Improve airflow by removing excess shrubbery and foliage, which can allow more sunlight and air circulation to reach the grass.

Step3 Apply a Preventative Fungicide

Applying a preventative fungicide that targets Pythium blight is one of the most effective ways to protect your lawn from this disease. It's best to apply the fungicide before any damage from Pythium blight occurs, helping to prevent symptoms like greasy spots and fuzzy rings. This is especially important if you've dealt with Pythium blight in the past.

When planning your fungicide program, rotate products to prevent the development of resistance. Ensure that you rotate based on both the active ingredients and the grouping as defined by the Fungicide Resistance Action Committee (FRAC). You can find FRAC group numbers on fungicide labels, which can simplify your decision-making. Check our Fungicide Use Guide for more details on how to select and rotate fungicides effectively.

Products we recommend for Step 3

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