Red Thread on Turf
By Gail Ruhl, Senior Plant Disease Diagnostician,
Red thread is caused by a fungus (Laetisaria
that attacks the
grass blades and leaf sheaths of many commonly cultivated turfgrasses
including Kentucky bluegrass, perennial ryegrass, and tall fescue.
thread gets its name from the red fungal structures that protrude
the tips of infected grass blades Red thread symptoms create brown
in the lawn, however crowns and roots are not infected, so plants
killed and turf eventually will recover.
The disease usually occurs from late May through
September, when temperatures are between 65-75° F, and especially when evenings
are cool and
moist. Red thread development is most common where turfgrass nutrition
poor and there are other factors that promote slow growing turf.
fertility of the soil is most important: proper and timely fertilization
will reduce the incidence of this fungal disease. Apply 1/2 to
1 pound of
nitrogen per 1,000 square feet of turf and maintain good fertility
throughout the growing season.
Other cultural practices that will help to prevent
disease include watering
infrequently but deeply, moistening the soil to a depth of 4-5
more at each irrigation. Mow often so that no more than 1/3 of
blade is removed at each clipping.
Turf Grass Disease Profile: Red Thread