Pythium Blight Control: How To Get Rid of Pythium Blight

Pythium Blight, also known as cottony blight, spot blight, or grease spot, is a damaging turfgrass disease that can plague commercial or residential landscapes. Pythium blight affects grass in the summer when the temperature and humidity are considerably high.

Grasses infected with Pythium Blight often go undetected by lawn owners because, in the early morning, turf infected with Pythium Blight appears to look wet with dew and darkly colored green slime. The effect of Pythium Blight also results in infested grasses looking greasy or oily.

When the weather becomes hotter, the Pythium Blight infected grass begins to wilt at an alarming rate, turns brown and then dries out before eventually dying. In other cases, a sign of the disease is white, cobwebby, mold-like growths of the fungus appearing on the leaves and blades of grass. At worst case, the solution to fighting the disease is changing your grass entirely and starting from scratch which may not be ideal with how time-consuming and expensive that would be.

If you have noticed pythium blight on your lawn, our DIY treatment guide will show you how to eliminate it with professional fungicides recommended by our lawn care experts.

Identification

Before you can carry out treatment, you need to be sure you are dealing with Pythium Blight and not some other disease or issue. Misidentification may lead to using the wrong treatment methods, which can waste your time and money. Here are some symptoms below to help you identify Pythium Blight.

• Pythium blight is often caused by various Pythium fungal species such as pythium aphanidermaturm, pythium graminicola, pythium ultimum and pythium vanterpoolii. It is a serious disease of cool-season turfgrasses during hot humid weather.
• On short-cut turf like bentgrass, putting greens or fairways, the disease initially appears as orange-colored spots. In the early morning, a light gray ring may or may not be present along the outer edge of the spot. The spots are typically 1 to 3 inches in diameter.
• If humidity levels stay high, especially at night going into early morning, a white fluffy mass of mycelium may appear. Sometimes this is called the "cottony blight" phase of development. If conditions remain favorable, the spots may grow bigger in a short amount on time.
• On high cut turf, large spots of brown patches can appear.

Refer to the image above and our description to help you in identifying Pythium Blight. If you are having trouble, you can contact us and we'll help you in correctly identifying your issue.

Inspection

After you have confirmed that you are dealing with Pythium Blight, you can move forward with an inspection. During this phase, you will locate where the Pythium Blight is thriving and how severe of an issue there is.

Where to Inspect

Pythium Blight thrives in areas during hot and humid days of summer when dew periods are long (usually more than 14 hours in duration) and night temperatures reach an average of 68 degrees or more. The initial presence of Pythium Blight is usually first noticed in low areas of turf where soil moisture is higher and dew begins to form early in the evening and lasts into the next morning.

Walk around your lawn and check where the Pythium Blight has developed and determine the level of severity. Creeping Bentgrass, Annual Bluegrass, Rough Bluegrass, and Perennial Ryegrass are the grass types most vulnerable to damage by outbreaks of Pythium Blight. The Pythium fungus can also affect Kentucky Bluegrass and Tall Fescue, but the development of the disease is minor and is usually not significant enough to cause damage to these plants.

What To Look For

Watch for white mold-like growths on grass blades and plants that look like cottony cobwebs. Established Pythium Blight will result in patches of dead grass.

Treatment

Prior to treatment, we suggest wearing the proper safety equipment for the job to prevent chemicals from coming in contact with your eyes or skin (gloves, safety goggles and long-sleeved clothing).

Our top recommendation to treat Pythium Blight is Mefenoxam 2AQ. Mefenoxam 2AQ is a systemic fungicide that contains the active ingredient Mefenoxam and is designed to get rid of various harmful fungal diseases, including Pythium Blight. It is also the most affordably priced option to tackle the disease. Mefenoxam 2AQ works systemically and is a preventative fungicide but may be used on established Pythium Blight to cure the disease.

Step 1 - Measure and Apply Mefenoxam

Start by first figuring out how much Mefenoxam 2AQ you need by calculating the square footage of the treatment area. To do this measure and multiply your lawn's length and width to get the total square footage to be treated (length x width = square footage). To spot treat Pythium Blight, Mefenoxam 2AQ must be applied at a rate of 0.49 - 0.98 fl. oz. of product per 1 to 5 gallons of water per 1,000 sq. ft. in a gallon of water.

Mix the appropriate amount of Mefenoxam 2AQ in a sprayer with water based on your measurement calculations and then apply the Mefenoxam 2AQ mixture via fan spray nozzle setting to the affected areas. Re-apply the product in 10 day intervals until the Pythium Blight is gone.

Prevention

After you have eliminated the Pythium Blight outbreak, you want to make sure it doesn't return. Prevention is the best cure when it comes to Pythium Blight. You must keep it from coming back by practicing organic control measures and routine maintenance. Here are some preventative tasks we suggest:

• We recommend applying Mefenoxam 2AQ as a preventative treatment before the disease is present. Apply to the foliage at 10 to 21 day intervals. During prolonged conditions apply to foliage at 14 day intervals.
• Control practices for residential lawns are based on avoiding excessive nitrogen fertility during the summer season, avoiding early evening irrigation, and improving air circulation so leaf surfaces dry more quickly.
• Avoid overwatering but watering your grass with 1 to 2 inches of water once a week.
• Remove as much thatch as possible from your lawn and address drainage issues so there isn't excessive soil moisture.

Key Takeaways

What is Pythium Blight?

• Pythium blight is a highly destructive turfgrass disease characterized by a white cobwebby coating turfgrass and plant life.

How To Get Rid of Pythium Blight

• Our top recommended fungicide to control Pythium Blight is Mefenoxam 2AQ. Timing is important when applying this product for best results.

Preventing Pythium Blight Reemergence

• Once your lawn has been treated, keep Pythium Blight from returning with a consistent lawn care maintenance program and preventative treatments of Mefenoxam 2AQ. Make sure not to overwater or over-fertilize.