White patch, also known as white blight, is primarily a disease of tall fescue in transition zone areas. The disease develops during periods of hot, humid weather and is most damaging to new plantings in the first year or two after establishment. Symptoms appear in white circles or patches up to 1 foot in diameter, and small white or tan mushrooms (about 1/4 inch in diameter) are produced directly on the blighted leaves. White patch is most damaging in tall fescue that is under-irrigated or deficient in nitrogen or other essential nutrients.
Host Grass Species
Month(s) with symptoms
May to September
patches (4 inches to 3 feet)
Foliar Symptoms - Location/Shape
blighting of entire leaves
Foliar Symptoms - Color
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
The white patch pathogen is most active during the summer when humidity is high and night temperatures are above 70°F. Stands of tall fescue that are under-fertilized, under-irrigated, heavily trafficked, or under other forms of stress are most prone to this disease.
Apply 3 to 4 lbs N per 1000 ft2 to tall fescue landscapes annually to maintain optimal growth and density. Approximately 2/3 of this nitrogen should be applied in the fall, with the remainder applied in the spring prior to May 1. Perform an annual soil test to ensure that soil pH and nutrient levels are optimal. Mow tall fescue regularly to a height of 3” to 3.5”. Use deep and infrequent irrigation to prevent drought stress and minimize leaf wetness periods. This is done by irrigating for a sufficient period of time to wet the entire root zone, then re-applying only when the root zone has become dry and the turf begins to show signs of mild drought stress. For best results, use the Turf Irrigation Management System available on TurfFiles to schedule irrigation based on weather conditions and turf needs.
Infestations of white patch are rarely severe enough to warrant fungicide applications. No fungicides are labeled for control of white patch, but azoxystrobin (Heritage) and flutolanil (ProStar) have shown some activity against the disease.
Note: Recommendations of specific chemicals are based upon information on the manufacturer's label and performance in a limited number of trials. Because environmental conditions and methods of application may vary widely, performance of the chemical will not always conform to the safety and pest control standards indicated by experimental data. The order in which brand names are given is not an indication of a recommendation or criticism.
Recommendations for the use of agricultural chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services does not imply endorsement by North Carolina State University or discrimination against similar products or services not mentioned. Other brand names may be labeled for use on turfgrasses. Individuals who use agricultural chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage regulations and examine a current product label before applying any chemical. For assistance, contact your county's Cooperative Extension agent.
© 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 March 7, 2011. 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.