Nothing is more frustrating than watching your lawn turn brown, yellow, or patchy despite your best efforts. In the humid North Texas climate, lawn diseases are a constant threat — and misdiagnosis is the #1 reason treatments fail. At Groundhogs Services, we’ve treated thousands of lawns across Mesquite, Dallas, Garland, and Rockwall, and we know exactly what to look for. Here’s your guide to identifying and treating the three most common lawn diseases in DFW.
Brown Patch (Rhizoctonia solani)
Brown patch is the most widespread lawn disease in Texas, and it’s especially aggressive in St. Augustine and tall fescue lawns.
Symptoms
- **Irregular circular patches** ranging from 6 inches to several feet in diameter
- **Tan or light brown lesions** on leaf blades with dark brown borders — this is the telltale sign
- **Grayish-black “smoke ring”** of active fungus at the outer edge of the patch in early morning when dew is present
- **Rapid expansion** during warm, humid weather (70-90°F)
- Grass pulls up easily from the stolons, which will be rotted and brown
When It Strikes in DFW
Brown patch is most active during our spring and fall when nights are cool (60-70°F) and days are warm with high humidity. In North Texas, expect outbreaks from March through May and again from September through November.
Treatment Strategy
Cultural controls first:
- **Water deeply but infrequently** — aim for 1 inch per week in a single application. Frequent shallow watering keeps the leaf blades wet overnight, which is exactly what the fungus needs.
- **Water in the early morning** (4-6 AM) so the grass dries before nightfall. Evening watering is the #1 cause of brown patch in DFW.
- **Raise your mowing height** — taller grass has deeper roots and better air circulation. For St. Augustine, mow at 3.5-4 inches.
- **Reduce nitrogen** — high-nitrogen fertilizers in spring and fall fuel brown patch. Use a slow-release, low-nitrogen formula during these seasons.
Fungicide treatment:
When cultural controls aren’t enough, apply a fungicide containing azoxystrobin, propiconazole, or thiophanate-methyl. Apply when night temperatures consistently exceed 60°F as a preventive measure. For active outbreaks, apply immediately and repeat every 14-28 days until symptoms stop spreading.
Take-All Root Rot (Gaeumannomyces graminis)
Take-all root rot is the silent killer of St. Augustine lawns in Texas. It attacks the roots, so by the time you see above-ground symptoms, significant damage has already occurred.
Symptoms
- **Yellowing or thinning grass** that looks like nutrient deficiency — often mistaken for iron chlorosis
- **Irregular, thinning patches** that slowly enlarge over weeks or months
- **Dark brown to black roots** — dig up a sample and rinse the soil off. Healthy roots are white; infected roots are dark and rotted.
- **Grass easily pulls up** because the root system has been destroyed
- **Worse in spring** as the lawn comes out of dormancy — the roots can’t support new growth
Why DFW Lawns Are Vulnerable
Take-all thrives in alkaline, compacted clay soil with poor drainage — which describes most of North Texas. Overwatering, excessive thatch, and high pH (above 7.0) create the perfect environment. New sod installations are especially susceptible because the root system hasn’t fully established.
Treatment Strategy
This disease requires a long-term approach. There’s no quick fix.
- **Apply a wetting agent** to improve water penetration through thatch and into the root zone
- **Lower soil pH** with sulfur or ammonium sulfate — target 6.0-6.5 pH
- **Core aerate** in spring and fall to reduce compaction and improve drainage
- **Apply a high-potassium, low-nitrogen fertilizer** to strengthen roots
- **Fungicide drench** with **azoxystrobin** or **tebuconazole** applied as a root-zone drench, not a foliar spray. Apply in **April and September** for preventive control.
- **Topdress with compost** — 1/4 to 1/2 inch of fine compost adds beneficial microbes that compete with the take-all fungus
Dollar Spot (Clarireedia spp.)
Dollar spot is less destructive than brown patch or take-all but far more common. It’s a sign your lawn is stressed and undernourished.
Symptoms
- **Small, silver-dollar-sized spots** of bleached, straw-colored grass — these can merge into large irregular patches
- **Hourglass-shaped lesions** on individual leaf blades with tan centers and reddish-brown borders
- **Fine, cobweb-like mycelium** visible on dew-covered grass in early morning
- **Worst on low-nitrogen lawns** — dollar spot is essentially a nitrogen deficiency symptom
When It Strikes
Dollar spot is active from late spring through early fall in DFW, especially during periods of heavy dew, light rainfall, and temperatures between 60-90°F. It’s most common on Bermuda and Zoysia lawns that haven’t been fertilized properly.
Treatment
- **Apply nitrogen** — 1/2 pound of quick-release nitrogen per 1,000 square feet will often clear dollar spot within a week
- **Water early morning** to reduce leaf wetness duration
- **Reduce thatch** — dollar spot thrives in thick thatch layers over 1/2 inch
- **Fungicides** containing **iprodione**, **myclobutanil**, or **propiconazole** are effective for severe cases
DFW-Specific Prevention Calendar
| Season | Action |
|——–|——–|
| Late February | Apply first fungicide preventive (azoxystrobin) for brown patch |
| March-April | Core aerate, apply sulfur for pH control, treat take-all |
| May-June | Monitor for dollar spot, apply nitrogen as needed |
| September | Second fungicide application for brown patch and take-all |
| October-November | Final aeration, compost topdressing, winterize |
When to Call Groundhogs Services
Lawn disease diagnosis requires experience. If you’re seeing brown patches, yellowing, or thinning grass and you’re not sure what’s causing it, don’t guess — you could waste money on the wrong treatment or make the problem worse.
Groundhogs Services offers professional lawn disease diagnosis and treatment programs for DFW homeowners. We’ll identify the specific pathogen, recommend the right cultural practices, and apply the correct fungicides at the right time.
Call us at (214) 713-1228 or visit groundhogstx.com to schedule a lawn evaluation. We serve Mesquite, Dallas, Garland, Rockwall, and the entire DFW metroplex.
