Turf - Red Thread Disease

The following is information on red thread disease of turfgrasses.

Laetisaria fuciformis, the causal agent of Red Thread, is now infesting susceptible perennial ryegrass and fine fescue turf. Infections are characterized by the appearance of short red threads (1/8” to 1/4” long) emerging from tan-colored leaf blades. Affected patches are typically pink in color and range from 1 to 6 inches in diameter. Kentucky bluegrass and tall fescue may also be affected in the spring. Red thread is typically found on “hungry” (low fertility) turf during cool, wet weather. Well-fertilized turf may also be attacked but to a lesser extent than nitrogen deficient turf. To obtain optimum disease control, maintain adequate fertility levels, keep turf properly irrigated, avoid excessive thatch, and apply Armada, Banner, Bayleton, Chipco 26GT*, Compass, Curalan*, Eagle, Endorse, Headway, Heritage, Insignia, Prostar, Rubigan, Tartan, Trinity or Touche* per manufacturer’s recommendations. (*Not for use on home lawns)

Red thread disease on bluegrass. Photo by Mary Ann Hansen, Virginia Polytechnic Institute and State University, Bugwood.org.

Information from Bruce B. Clarke, Ph.D., Specialist in Turfgrass Pathology, Rutgers University.