What is Take-All Root Rot?
Take-All Root Rot (TARR) is a serious fungal disease that affects turfgrasses, especially in warm, humid regions like the southeastern United States. Caused by the fungus Gaeumannomyces graminis var. graminis, TARR is most commonly found in St. Augustinegrass, but it can also impact Bermuda, Centipede, and Zoysiagrass lawns. The disease attacks the roots, stolons, and rhizomes, weakening the grass and making it susceptible to other stresses.
How to Identify Take-All Root Rot
One of the first signs of TARR is the appearance of irregular yellowing patches in the lawn, typically during spring or fall when temperatures are mild. These patches can expand over time and merge, forming large, dead areas. Unlike drought stress or nutrient deficiency, affected grass does not respond well to watering or fertilization.
To confirm TARR, you can gently pull on the yellowing grass. If it comes up easily with little resistance and has dark, rotted roots or blackened stolons, it’s likely infected with Take-All Root Rot. In severe cases, grass may die off completely, leaving bare patches that are slow to recover.
Causes and Risk Factors
Take-All Root Rot thrives in stressed lawns with poor drainage, heavy thatch, or compacted soil. Overwatering, excessive nitrogen fertilizer, and high pH levels can also promote the growth of the fungus. Because the disease attacks the root system, affected grass becomes more vulnerable to heat, drought, and foot traffic.
Management and Prevention
There’s no quick fix for TARR, but cultural practices can help manage and prevent it:
- Improve soil drainage by aerating compacted areas.
- Avoid overwatering and allow the lawn to dry between irrigation cycles.
- Use a balanced fertilizer and avoid applying too much nitrogen.
- Lower soil pH if it’s above 7.0 by applying sulfur-based amendments.
- Topdress with compost to enhance soil health and beneficial microbes.
In severe cases, fungicides labeled for Take-All Root Rot may be applied in early spring or fall, but they are most effective when used alongside proper lawn care practices.
Understanding and addressing Take-All Root Rot early can help preserve the health and appearance of your lawn year-round.
This post was written by a professional arborist at Arbor Wise Professional Tree Care. Robert Miller is the owner of Arbor Wise Professional Tree Care, a locally owned and operated tree service company that offers superb lawn care by the most experienced Arborists. Arborwise Tree Services is a tree removal company that offers stump removal, tree pruning, stump grinding, fertilization, and tree restoration. We have an extraordinary lawn care industry notoriety covering the Pinellas county area.
