Friday, May 22, 2009

Turf - Red Thread

Red thread disease in turf has been found recently. The following is more information.

Red thread has been diagnosed in a mixed turf of bluegrass and perennial ryegrass. The infected patch had a pink cast with red fungal threads easily seen upon close inspection. Although considered a disease of stressed turf, all turf can be infected under these ideal conditions. Red thread only infects the blades causing temporary damage. Infected turf will recover with time. Fungicides applied at the first signs of infection may help reduce damage but treatment is not usually warranted.

Red thread is a foliar disease that usually occurs on taller mown turfgrasses during spring and fall. The disease is often associated with malnourished, low quality, slow growing turf, but the effects of the disease are largely cosmetic. Red thread symptoms create an undesirable appearance, but crowns and roots are not infected, so plants are not killed and turf eventually will recover.

Red thread most commonly affects Kentucky bluegrass, perennial ryegrass, and tall fescue. Outbreaks usually occur in low maintenance turf stands such as residential lawns, golf course oughs, and some low budget athletic fields. Red thread development is most common where turfgrass nutrition is poor and there are other factors that promote slow growing turf.

The most important nonchemical (cultural) control option involves implementing an adequate nitrogen fertility program. A good fertility program implemented over two to three years will drastically reduce further red thread problems. Other cultural practices that promote healthy turf and vigorous growth also help suppress red thread. Outbreaks may be reduced further by avoiding irrigation practices that extend dew periods (such as watering in the late afternoon and early evening).

Photo from the Purdue University fact sheet BP-104-W on red thread disease of turf.

Information from Bob Mulrooney, Extension Plant Pathologist, UD and Purdue University fact sheet BP-104-W by Philip Harmon, Graduate Research Assistant and Richard Latin, Professor of Plant Pathology

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