Take-All Root Rot is caused by a fungus that attacks the root system of turfgrass. It starts in the soil and moves upward, damaging the roots and stolons (runners). Once infected, the roots lose their ability to take in water and nutrients, causing the grass to yellow, thin out, and eventually die in irregular patches.
St. Augustine grass is the most commonly affected in Austin, but Bermuda and Zoysia lawns can also be hit. The patches usually start small — a few inches across — but can spread several feet over time. When you pull on the grass in these areas, it often lifts easily from the soil because the roots are short, dark, and rotted.
How It Starts
In Austin, Take-All Root Rot tends to develop during our mild, wet spring and fall seasons. The fungus becomes active in cool, damp soil and continues spreading when moisture stays around too long. Lawns that hold water, are over-irrigated, or have poor drainage are most at risk.
Our local soils are often alkaline, and that high pH also favors the fungus. Add in lawn stress from mowing too short, compacted soil, or heavy shade, and you’ve got a perfect recipe for Take-All to move in. Lawns weakened by drought, too much fertilizer, or herbicide damage are especially susceptible.
Many homeowners notice the symptoms in spring when the grass is trying to green up. Infected areas stay yellow, thin, and weak even with watering or fertilizer. By summer, those spots can brown out completely under heat stress.
