Red thread
continues to be a problem on Kentucky bluegrass and perennial ryegrass
turf throughout the northern U.S. as of May 2000. Although this
disease is easily controlled with fungicides, increasing the fertility
of these lawns should effectively decrease the severity of this
disease.
Red thread is a serious problem in many Kentucky bluegrass
and perennial ryegrass turfs. Generally, these turfs are somewhat
deficient in nitrogen. Increase nitrogen to decrease the severity of
the disease. If the disease persists, a fungicide application may be
recommended.
Perennial ryegrass is especially susceptible to red thread.
Circular bleached out areas often form in lawns. The diagnostic key to
this disease is the presence of red threads (stroma) protruding from
the leaf blade.
Red thread (causal agent: Laetisaria fuciformis) is a
serious spring disease of Kentucky bluegrass, fine fescue and
perennial ryegrass during periods of heavy dews, fog, and light rains.
Circular to irregular shaped patches form that are straw to pinkish in
color. A diagnostic key for this disease is the presence of red
threads (stroma) coming out of the leaf blade. In addition, pink
cottony balls (small in diameter) may be present (especially on
perennial ryegrass). Sometimes this heavy reddish mass of mycelium
causes confusion with pink snow mold. Red thread is especially severe
on slow growing, nitrogen deficient turf. Nitrogen applications can
help reduce the severity of the disease but avoid excessive nitrogen
rates. TechNotes
Volume III, Issue 21, May 25, 2000; Volume III, Issue 19, May 11,
2000; Volume III, Issue 17, April 28, 2000; Volume III, Issue 14,
April 6, 2000
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