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November 11 - - With the wet conditions and lower temperatures,
we may start seeing activity from cool weather pathogens
before winter sets in. If the conditions are right this
winter, we won't see gray snow mold until after the snow
melts, but pink snow mold could become active before snowfall.
This is especially true for today's conditions: cloudy,
morning drizzle, and mid '50s. North Chicago courses should
be on the lookout for this disease, and if it does show
up a curative fungicide application may be necessary before
the usual preventative application (which should be applied
as close to snowfall as possible).
April 4
- - Pink snow mold has exploded here on the Midwest Golf
House putting green over the last week. In honesty, our
preventative application was probably not put out at a high
enough rate last fall, so we paid the price and are going
to reapply. Only a few patches were first noticed as we
pulled off the protective cover from a portion of the green.
Over the last few days these patches have multiplied to
15-20 patches. Another factor conducive to our outbreak
is that mulch was used as a winter protectant over the seedlings
as well as the cover.
Other reports of this disease
have been very widespread, and were limited to areas under
covers, or low, wet areas that are predominately Poa annua.
Gray snow mold, unlike this disease, will probably not be
a problem this year at all due to the lack of snow cover
during the winter.
Overview:
Caused by the same pathogen as Microdochium patch,
this disease forms smaller patches than gray snow mold,
and the diseased turf can take a copper to red, or pink
tinge depending on the environmental conditions (See Photos).
The disease is also favored by higher temperatures
than gray snow mold (>40 F) and is often a late winter/early
spring disease. Pink snow mold fungi are also more
pathogenic than gray, leading to severe infections in the
crown and stolons of plants and long term loss of infected
plants.
Cultural controls:
FALL: Apply fertilizer at least a few weeks before
snow cover, with slow release forms of nitrogen being preferred.
Continue to mow grass until late fall to insure the
snow does not fall on a tall canopy.
SPRING: Promote rapid drying and warming of disease
prone areas by removing snow and improving drainage.
Lightly fertilize to encourage new growth, but not too much.
Chemical controls:
For preventative applications, apply as close to first
snowfall as possible. Mixtures of chlorothalonil
+ iprodione (i.e. Chipco 26GT + Daconil) work well for snow
mold suppression, as does PCNB. There is some risk
of phytotoxicity with PCNB if warm weather (>80 F) occurs
up to 3 months after application. Fungicides in the
DMI or strobilurin group also control pink snow mold.
Unlike gray snow mold, curative applications after the
snow melts are a good idea if you have pink snow mold since
this fungus can still be active at higher temperatures.
Click here for
differences in control recommendations between the two.
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