DAMPING OFF

damping off mycelium	Characteristic	Description
	Host Grass Species	bentgrass, bluegrasses, fescues, ryegrasses
	Month(s) with symptoms	all
	Stand Symptoms	spots, patches (4 to 12 inches), or irregular distribution across turf stand
	Foliar Symptoms - Location/Shape	blighting of entire leaves
	Foliar Symptoms - Color	tan, brown, or black
	Root/Crown Symptoms	roots, stolons, rhizomes, and/or crowns dark brown or black
	Fungal Signs	mycelium or none

 

Note: Still not sure if this is the right disease? The Turfgrass Disease Identification program may be helpful. Or consult the experts at the Turf Diagnostics Lab. Check the TurfFiles glossary for definitions of unfamiliar terms.

FACTORS AFFECTING DISEASE DEVELOPMENT

Turfgrasses are most susceptible to damping off during germination and seedling emergence. After emergence, the turf gradually becomes resistant to the disease as it matures. Damping off is most severe when temperatures or light levels are unfavorable for seedling growth. Pythium causes the majority of damping off problems during warm or hot weather, whereas Rhizoctonia is more prevalent during cool weather.

The disease is encouraged by excessive nitrogen fertility and extended periods of leaf wetness. High seeding rates encourage damping off by producing dense populations of seedlings that mature more slowly and remain wet for extended periods of time. 

CULTURAL CONTROL

Use recommended seeding rates to encourage rapid seedling maturation and prevent excessively dense canopies. Apply a high phosphorous (P) starter fertilizer at the time of seeding to provide 1 pound of P per 1,000 square feet. To encourage rapid germination, water lightly and frequently to keep the seedbed moist but not saturated. As the seedlings emerge and develop a root system, gradually reduce the irrigation frequency, and ensure that the seedling leaves dry completely in between irrigation cycles. Apply a thin layer of straw or other mulching material to hold in moisture, but do not over-apply as this will retain too much moisture and increase the risk of damping off. A second fertilizer application is typically made around the time of the first mowing, but do not apply more that 0.5 pound of readily available nitrogen per 1,000 square feet. Do not attempt to establish turfgrasses in low-lying, wet areas where damping off is most severe. 

CHEMICAL CONTROL

Fungicides are available for control of damping off, and may be applied as seed-treatments or directly to the seedbed. If damping off is observed, submit a sample to a diagnostic lab for accurate diagnosis because different fungicides are needed for control of Pythium and Rhizoctonia species. For a ranking of products for control of damping off, refer to information sheets on Pythium blight or brown patch.

© North Carolina State University. This information sheet was prepared by Lane P. Tredway, Gail G. Wilkerson, Bridget R. Lassiter, Jenifer J. Reynolds, and Gregory S. Buol. Departments of Plant Pathology and Crop Science, College of Agriculture & Life Sciences, North Carolina State University. Prepared April 29, 2008. Available on-line at www.turffiles.ncsu.edu. This publication was made possible through a grant provided by the Center for Turfgrass Environmental Research & Education (CENTERE) whose purpose is to support worthwhile projects that will benefit both the private sector and the public, and protect the environment.