Oklahoma’s hot, humid summers create ideal conditions for several lawn diseases. The most common are brown patch (affects fescue primarily), dollar spot (common in Bermuda), and take-all root rot (increasingly problematic). Most lawn diseases thrive when grass is stressed by improper watering, poor drainage, or environmental conditions. Early identification is key because diseases spread quickly. Complete Lawn Care can help diagnose mystery lawn problems and recommend treatment options.
Brown Patch (Rhizoctonia)
Primary target: Fescue and other cool-season grasses (can affect Bermuda but less common)
Appearance: Circular brown patches ranging from a few inches to several feet in diameter. Active infections show a darker “smoke ring” at the expanding edge, especially visible in the early morning.
When it strikes: Hot, humid weather (daytime 80-90°F, nighttime above 60°F) with prolonged leaf wetness. Most common from June through September in Oklahoma.
Prevention and treatment: Water in the early morning only so grass dries by evening. Reduce nitrogen fertilization during hot weather. Improve air circulation. Fungicides containing azoxystrobin or propiconazole can treat active infections.
Dollar Spot (Clarireedia)
Primary target: Bermuda grass and Zoysia (can affect Fescue too)
Appearance: Small, silver-dollar-sized tan spots that can merge into larger irregular patches. Individual grass blades show bleached lesions with reddish-brown borders. May see white, cobweb-like fungal growth in early morning dew.
When it strikes: Moderate temperatures (60-80°F) with high humidity and moisture. Often appears in spring and fall in Oklahoma. Low nitrogen levels make grass more susceptible.
Prevention and treatment: Maintain adequate nitrogen levels (unlike brown patch, dollar spot is worse in underfed lawns). Water deeply but infrequently. Remove dew in the morning by mowing or dragging a hose across the lawn. Fungicides are effective if needed.
Take-All Root Rot (Gaeumannomyces)
Primary target: St. Augustine grass (not common in Tulsa) and Bermuda grass
Appearance: Irregular yellow or light-green patches that don’t respond to fertilizer or water. Roots are short, dark, and rotted. Grass pulls up easily because roots are dead.
When it strikes: Spring and fall during mild, wet weather. Alkaline soil pH (common in Oklahoma) makes it worse.
Prevention and treatment: Improve drainage. Apply sulfur to lower soil pH. Avoid excessive nitrogen. Fungicides have limited effectiveness once established. Focus on prevention and building overall lawn health.
Spring Dead Spot
Primary target: Bermuda grass
Appearance: Circular dead patches that appear in spring when Bermuda greens up. Patches are completely dead, not just slow to green. Often recur in the same spots year after year, sometimes getting larger.
When it strikes: The fungus actually infects roots in fall and winter. Damage becomes visible in spring. Cold, wet winters followed by late spring freezes worsen the problem.
Prevention and treatment: Reduce thatch. Improve drainage. Avoid excessive nitrogen in late summer. Fungicide applications in fall (before dormancy) can help prevent infection. Affected areas usually fill in by mid-summer as Bermuda spreads.
Fairy Ring
Primary target: All grass types
Appearance: Circular or arc-shaped rings of dark green grass, dead grass, or mushrooms. Rings expand outward each year. Caused by fungi feeding on decaying organic matter in the soil.
When it strikes: Usually appears after wet weather in spring through fall. Often found in lawns with buried organic debris (old tree roots, construction lumber).
Prevention and treatment: Difficult to control. Core aeration helps water penetrate the hydrophobic (water-repelling) soil in the ring. Remove mushrooms if they appear. Fungicides have limited effectiveness. Often the best approach is patience; many fairy rings eventually exhaust their food source and disappear.
General Disease Prevention Tips
Water correctly: Early morning only. Deep and infrequent. Most diseases need wet conditions.
Don’t over-fertilize: Excess nitrogen promotes lush growth that’s disease-susceptible.
Improve air circulation: Trim overhanging branches and shrubs that block airflow.
Mow properly: sharp blades, correct height, and following the 1/3 rule reduce stress.
Aerate annually: Reduces thatch and compaction, improving overall lawn health.
When to Call Complete Lawn Care
If you’re seeing circular dead spots, unusual patches, or unexplained decline in your lawn, contact us for diagnosis. Many problems look similar but have different causes and treatments. Our experience with Oklahoma lawns helps us identify issues quickly and recommend the right solution. Our 7-step program builds overall lawn health, which is your best defense against disease.
Contact Complete Lawn. Care:
Phone: (918) 605-4646 | Email: [email protected] | Online: completelawncaretulsa.com/get-a-quote