How to Manage Pests
UC Pest Management Guidelines
Pathogen: Gaeumannomyces graminis var. avenae
(Reviewed 9/09, updated 9/09, pesticides updated 12/16)
In this Guideline:
DESCRIPTION OF THE DISEASE
Take-all patch appears as circular or ring-shaped dead areas that range from a few inches up to 3 feet or more in diameter. Dying bentgrass at the advancing margins of these areas has a purplish tinge. The roots of the diseased plants are rotted and have dark strands of mycelium visible on the surface of the roots. Large black perithecia, which are globular or flask-shaped fungal fruiting bodies, may be visible with the use of a hand lens. The pathogen survives in grass debris and living grass plants.
Bentgrasses are the most susceptible, but bluegrass, fescues, and ryegrasses are also susceptible to take-all patch.
CONDITIONS FAVORING DISEASE
In California, take-all patch principally occurs in late fall and winter when air temperatures are 50° to 60°F and soils are wet or moist, but symptoms may not manifest until the turf is exposed to periods of drought or heat stress. Soil conditions that favor the disease include light texture, low organic matter, low or unbalanced fertility, high pH, and high moisture. The disease may be spread by spores produced by the perithecia, in infested soil and sod, or by dethatching and aerification equipment.
To prevent the development of this disease, make sure the turfgrass has adequate soil drainage and fertility.
Recovery of bentgrass can be slow on closely mowed turf; affected areas can be resodded if necessary, and some varieties with improved tolerance are available. Raising manganese levels in the soil (or lowering pH) appears to suppress the disease. If the soil pH is above 7, lower it using elemental sulfur. Fertilize in fall with ammonium sulfate. Also, irrigate based on evapotranspiration needs of turfgrasses.
Fungicides may be necessary on golf greens that have experienced the disease in the past. Apply a fungicide on a preventive basis in fall.
UC IPM Pest Management Guidelines: Turfgrass
A. Downer, UC Cooperative Extension, Ventura County
Acknowledgment for contributions to Diseases:F. Wong, Plant Pathology, UC Riverside
J. Hartin, UC Cooperative Extension, San Bernardino County
M. E. Grebus, Plant Pathology, UC Riverside