Page 22 - 2025 GM spring

consistent conditions for study.
Controlling plot conditions during
winter is challenging, and there are
few research facilities in regions
where winters are consistently harsh.
Additionally, laboratory results are
difficult to verify in the field.
This WinterTurf project aims to
overcome these obstacles by
gathering data from multiple sources,
including pre-winter, weekly, and
post-winter surveys from golf course
Superintendents, environmental
sensors, satellite imagery, site
management information, and
weather data. If you are interested in
participating in future years of data
collection, you can learn how
to get a sensor at z.umn.edu/sensors
or how to help collect data at
z.umn.edu/interest-survey. This colla-
borative research effort promises to
deliver practical solutions that can be
implemented across diverse cold
climate regions.
Understanding Winter Stress
In the ICEBREAKER study, which was
conducted with five different
turfgrass species, ice cover was
maintained on greens-height turf for
over 12 weeks. Sensors measured
oxygen and carbon dioxide (CO2)
levels, while measurements of
photosynthetic action and visual
quality ratings were taken to assess
the impact. The results showed that
velvet bentgrass was the most
resistant to extended ice cover, with
creeping bentgrass and slender creep-
ing red fescue also performing well.
In contrast, annual bluegrass
was completely killed in both years
of the study, indicating a susceptibility
to prolonged ice cover. Chewings
fescue experienced severe damage
in both years, with some death
occurring in the second year. The
study suggests that the long duration
of high CO2 levels is likely a significant
factor in the death of annual
bluegrass, raising questions about
the impact of other gases.
Further research is needed to
answer these questions and better
understand the mechanisms behind
ice encasement survival. The next
project will investigate whether
heavy topdressing can improve
winter survival rates of golf course
greens.
Ontario Turfgrass Symposium: Lecturer Ed McNab
We invite Superintendents across North America to get actively involved
in the WinterTurf project. Your participation can make a significant impact,
whether through completing surveys, collecting winter data, or sharing data
from previous winters. Join us in advancing the science on winter stresses on
turfgrass and improving management practices for golf course greens.
Together, we can develop more resilient and sustainable turfgrass solutions.
A CASE STUDY ON THE EFFECTS OF LONG TERM DMI USE ON DOLLAR
SPOT POPULATIONS By Ed McNab
Dollar spot disease, caused by multiple fungal pathogens in the Clarireedia
genus (formerly Sclerotinia homoeocarpa), is a prevalent and economically
significant disease affecting turfgrasses. In Ontario, and the surrounding
Great Lakes region, this disease is primarily caused by Clarireedia jacksonii.
Symptoms of this disease include 3-5 cm wide patches (dollar-sized) of
blighted grass, “hourglass” lesions, and cobweb-like growth with heavy dew.
This disease can severely impact the aesthetic and functional quality of golf
course fairways, tees, and greens. Both cultural and chemical controls are
crucial to maintaining the high standards of turfgrass health required course
playability and appearance. But what can we do when the chemical controls
do not seem to be working as well as they used to?
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• CGSA • GreenMaster