Pythium Blight: Identification and Treatment in Georgia
Pythium blight moves faster than any other lawn disease. Learn how to spot it, stop it, and prevent the conditions that cause it in Middle Georgia summers.
Disease profile
What Is Pythium Blight?
Pythium blight is a fast-moving, destructive disease that can devastate a lawn in 24 to 48 hours under the right conditions. It thrives in hot, humid weather with overnight temperatures above 68°F — the exact conditions Middle Georgia sees every summer. Standing water, poor drainage, and over-irrigation create the perfect environment for pythium to explode.
Symptoms
How to Identify Pythium Blight
Greasy, dark, water-soaked patches that appear suddenly
Patches range from 1 to 6 inches in diameter initially
Affected grass feels slimy and mats together when walked on
White, cottony mycelium visible in early morning on wet turf
Turf collapses quickly — healthy-looking grass turns brown within hours
Streaked pattern following water drainage paths across the lawn
Conditions
What Causes Pythium Blight
Favorable Conditions
Nighttime temperatures above 68°F combined with daytime highs above 86°F
High humidity (above 90%) and prolonged leaf wetness
Standing water or poor drainage after afternoon storms
Overwatering or irrigation that runs in the evening
Compacted soil that doesn’t drain well
Excessive nitrogen fertilization during peak summer heat
Susceptible Grass Types
Treatment
How to Prevent and Treat Pythium Blight
Cultural Prevention
Water only in the early morning — never in the evening during summer
Fix drainage issues and eliminate areas where water pools
Avoid heavy nitrogen applications during peak summer heat
Core aerate to reduce compaction and improve water infiltration
Mow regularly and keep blades sharp to minimize leaf damage
Avoid mowing or walking on wet turf, which spreads the pathogen
Professional Treatment
Pythium moves fast, so we treat aggressively. Preventive fungicide applications during peak summer heat are the best defense for lawns with a history of pythium. Curative treatment at the first sign of symptoms can stop the spread, but damaged turf takes time to recover. We also evaluate drainage and irrigation to address the underlying conditions that invite pythium.
Left untreated
What Happens Without Treatment
Pythium blight can destroy large sections of turf within 48 hours. The fungus spreads through water movement, so entire drainage paths can collapse. Dead turf doesn’t recover — it needs to regrow from surrounding healthy grass or be re-established. Without treatment, the same areas get hit every summer.
Common questions
Frequently Asked Questions About Pythium Blight
Why did my lawn die overnight?
Pythium blight is one of the few diseases that can kill turf within 24 to 48 hours. If you noticed greasy, dark patches that appeared suddenly during hot, humid weather, pythium is the likely culprit. Immediate treatment is critical.
Does overwatering cause pythium blight?
Overwatering is the single biggest contributing factor. Standing water, evening irrigation, and soggy soil create the exact conditions pythium needs. Switching to early-morning deep watering with proper drainage dramatically reduces risk.
Can pythium-damaged turf grow back?
The grass in affected areas is dead and won’t recover on its own. Bermuda and zoysia will fill in from surrounding healthy turf over several weeks. Severely damaged areas may need sod or plugs to fully recover.
How do I prevent pythium blight in summer?
Water early in the morning, fix drainage problems, avoid evening irrigation, and don’t over-fertilize with nitrogen during peak heat. For lawns with recurring pythium, preventive fungicide during June through August is the most reliable protection.
Related diseases
Other Diseases Active in the Same Season
Take action
Stop Pythium Blight Before It Spreads
Every day without treatment is another day the damage gets worse. Get professional disease control backed by our expert lawn care team.
