following question was sent to the P&PDL diagnosticians here
at Purdue University:
Question: Could you please discuss red thread and how to
get rid of it?
Answer: Red thread first appears as
small (quarter to golf ball size) spots in the turf. These spots
are initially purplish-blue or water soaked and eventually dry
out to a tan color. Upon closer observation, a distinctive red
to coral colored "thread" is
often seen growing from tips of infected leaves. This thread is
the body or mycelium of the fungus and serves to spread the fungus.
This disease is most common on poorly fertilized, slow-growing
turf with prolonged periods of rain, high humidity, and temperatures
between 65 and 75 degrees. Control of red thread is primarily accomplished
through proper fertilization to maintain consistent but not excessive
growth. In addition to fertilizer applications made in September
and November, apply 0.75-1.0 lb N/1000 sq. ft. in late May using
primarily slow release fertilizer. Slow release sources include
sulfur- or polymer-coated urea, urea formaldehyde, methylenediurea,
dimethylenetriurea or natural organic nitrogen. Perennial ryegrass
is especially susceptible t
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