Red Thread in Turf

Dr. Kevin W. Frank & Dr. Joe Vargas, Jr.
Michigan State University

The frequent rains this year have not only resulted in mowing challenges but have also resulted in some turf areas in need of nutrition.  Not surprisingly reports of red thread (Laetisaria fuciformison) on lawns and landscape turf areas have been frequent for several weeks now.  It seems that every year we observe red thread on lawns or golf course roughs and often the outbreak follows the seed head production period when the plant is probably looking for a little extra nutrition.  The common lawn mix turfgrasses Kentucky bluegrass, perennial ryegrass, and fine fescue are all susceptible, with perennial ryegrass being particularly susceptible.   Red thread is typically active during wet, moist periods when temperatures range from 55 to about 80 degrees. Red thread can be identified by the pinkish-red strands (stroma) that extend from the leaf blade tip.  The pinkish-red strands are easily observed in the morning when the turf is still moist from dew.  The areas infected by red thread will die and the turf may appear wilted.  Red thread can be mistaken for dollar spot in turf as the patchy type kill is very similar.  This is one of those diseases you need to get on your hands and knees to check out to make sure you know that it is red thread.  Fungicide applications are usually not necessary in dealing with red thread; a fertilizer application will often help the turf outgrow the damage.

Red Thread in Kentucky bluegrass

Red Thread with pink stroma visible.