Snow mold damage to a lawn
Both gray and pink snow mold can occur in Western Pennsylvania. Gray
snow mold is generally the less serious because it kills the blades
of affected grasses, but it does not kill the crowns or roots, as
pink snow mold can.
When the snow melts in spring, it reveals circular patches of
bleached out-looking lawn that range in size from a few inches to
several feet across. After long periods of snow cover, the entire
lawn can be affected. The blades of grass in those areas are dead
and matted together.
of snow cover can lead to this look in March
Gray snow mold usually only occurs when we get snow cover before the
ground has frozen. Gray snow mold can be distinguished from pink by
the presence of fungal bodies called sclerotia. They appear as
pinhead-sized light to dark brown hard structures embedded in leaves
and crowns of infected turfgrass. Sclerotia are not present with
pink snow mold. Simply rake out the affected areas thoroughly and
your lawn should recover on its own. Fungicide applications are not
effective in helping your lawn recover in the spring.
mold earned its name due to its pinkish color
Cultural control methods are preferred over fungicide applications
for controlling snow mold on home lawns. These include mowing your
lawn well into fall, until it has stopped actively growing. Your
last cut of the season should be slightly shorter than you would
normally cut your lawn, say down to 11/2 to 2 inches. This keeps the
grass from matting down on itself under snow cover, which creates a
favorable environment for the development of snow mold. Rake and
remove fallen leaves from the lawn before snowfall. Try to avoid
piling snow on the lawn when shoveling sidewalks and driveways.
VIDEO: Snow Mold
Avoid fertilizer applications that contain excessive nitrogen in
mid-fall, from late September through early November. Kentucky
bluegrass and fine fescues tend to be more resistant to gray snow
mold than perennial ryegrass or tall fescue. If fungicides are used,
they should be applied around Thanksgiving to prevent gray snow mold
from developing. Chloroneb, Bayleton (triadimefon) and thiram are
labeled to control gray snow mold on residential lawns.
of grass you plant, and when you apply fall fertilizer, can lead to stark differences like you see
along this property line
Pink snow mold is slightly different and can cause more severe
damage because it can infect crowns and roots as well as the blades.
Why is it called "Pink?"
The disease is named for the pink fungal spores that accumulate on
the leaves of infected grass. Patches of turf appear bleached out
and dead but with a pinkish cast. Sclerotia are not present. Pink
snow mold develops only under snow cover. A related disease, caused
by the same fungus, is called microdochium patch and can develop in
cool, wet weather without snow cover.
Controls for Snow Mold
The same cultural controls that help prevent gray snow mold work to
prevent pink. Kentucky bluegrass and fine fescues are more resistant
to pink snow mold than perennial ryegrass. Fungicide applications
may be recommended for newly seeded lawns. Mancozeb, Cleary's 3336.
Pruning snow damage from plants
Pink patch on Lawns