Causal Agent:
Gaeumannomyces graminis var. graminis
Susceptible Turfgrasses:
Bermudagrass
St. Augustinegrass
Seashore paspalum
Kikuyugrass
Identification:
Take-All Root Rot can manifest in several ways:
Patch Symptoms:
Appears in patches or rings, which may coalesce into irregularly shaped areas spanning several feet (up to 1.5 meters).
Initial Signs of Stress:
Reduced growth, chlorosis (yellowing), and leaf dieback in stressed turf.
Contributing stress factors include traffic, poor drainage, or shade.
Progression:
Turf declines to tan, yellow, or orange before collapsing.
Root and Rhizome Damage:
Sparse, rotten roots, stolons, and/or rhizomes are evident in affected areas.
Favorable Conditions:
Conditions that promote Take-All Root Rot include:
Temperature Range:
The pathogen thrives across a broad range of soil temperatures.
Moisture and Drainage:
Infection is likely in poorly drained areas with extended wet weather.
Most severe in soils with pH levels greater than 7.0.
Stress Factors:
Low light levels, cool temperatures, and turf stress from low mowing, inadequate fertility, excessive traffic, or shade increase susceptibility.
Nematode Pressure:
High populations of plant-parasitic nematodes contribute to disease severity.
Management Tips:
Soil pH Management:
Maintain soil pH below 7.0 to reduce pathogen activity.
Fertility and Nutrition:
Apply balanced fertility programs with adequate nitrogen, phosphorus, and potassium.
Improve Drainage:
Address drainage issues in poorly drained areas to minimize prolonged wetness.
Fungicide Applications:
Preventive systemic fungicides are most effective when applied in cool, moist conditions.
Cultural Practices:
Avoid low mowing heights and reduce traffic in affected areas.
Increase light exposure by trimming overhanging branches or removing excessive shade.
Nematode Management:
Monitor and manage plant-parasitic nematodes with nematicides or organic amendments.
