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Weather Review:
Our hot and humid summer weather pattern has continued over the
region for the last few weeks, but there have been some welcome
cool "breaks" in the pattern. Recently, these cool fronts
have brought some much-needed rainfall to dry areas around the
state, including central Illinois. For the Chicago metro area,
we now have reached 20 days of 90F or greater temperatures for
the daily high, and approximately 33 days > 85F. The twenty
90F days surpasses the 2001 season total, and equals that of 1999,
and its only the last week of July; there is still the potential
for quite a few more hot days before autumn gets here. We have
quite a bit further to go to reach the abysmal totals from 1995,
however - see the table below. Soil temperatures have reached
well into the upper 80s to low 90s F as well, meaning that most
cool season turf roots (and foliage) are under "environmental
stress." Shallow rooted Poa annua and Poa trivialis have
been showing signs of heat stress/decline (see
pest bulletin July 22), and this will probably continue off
and on over the next few weeks as the heat waves move through
the region.
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Number of Days with Daily High Temperatures:
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85+
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90+
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95-100+
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2002*
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33
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20
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4
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2001
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43
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18
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2
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2000
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31
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4
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0
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1999
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48
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20
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3
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1995
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64
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30
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11
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Several superintendents have commented that the last week of
July and the first week of August are their toughest - in terms
of potential turf stress and decline of Poa. The turf is not only
facing the accumulating heat stresses (high air and soil temps)
of summer, but also is confronted with the loss of root function
from soil compaction and low aeration, wear and tear on leaf tissue
from mowers and golfers' feet & carts, and diminishing availability
of nutrients from spring or early summer fertilizations. During
heat waves, it is important to control as much of the stress on
turf as possible by: hand watering or syringing hot spots to cool
the turf, controlling cart and mower traffic on weak areas, reduced
mowing frequency or raising the cutting height, and reducing other
aggressive maintenance practices, especially on greens (topdressing,
rolling, grooming, etc). Take advantage of cool breaks in heat
waves to spike or solid tine aerify compacted soil areas or localized
dry spots, lightly fertilize (esp. with soluble liquid applied
fertilizers), and topdress or brush/groom greens or tees.
Diseases:
Pythium blight has been active off and on over the past
few weeks, especially on longer canopy turf (intermediate roughs
and some fairways); scouting should continue during hot and humid
weather. Pythium and other high temp/high moisture diseases
have not been severe for most regions of Illinios, perhaps because
of the lack of rain and near drought conditions. Now that rains
have begun to return with the heat, Pythium and brown patch
activity could increase (see
Pest Alerts page). Most disease related complaints during
the recent heat wave were for fairy rings and localized dry spot
(LDS). (see
the July 15 Pest Bulletin for more info). Dollar spot has
remained fairly active despite the heat, although we have seen
it wax and wane on our fungicide trials during the hottest weather
…
Insects:
Feeding injury from Black Cutworm larvae and Japanese Beetle
adults continues to be reported. Birds have been flocking to fairways
for tasty morsels, possibly sod webworm as well as cutworm larvae.
See
the most recent Home Yard and Garden Newsletter for more info
on sod webworms. Mound building ants continue to be a problem,
as well. Some of the baits we have discussed in the past have
shown some success, but it appears that most infested areas will
have to be retreated after a few weeks. Typically you will see
some suppression of the mounding, and then they return later (sounds
like the same situation with standard insecticides like a Dursban
drench). Once the baits and baiting techniques are refined a little
bit for northern turf applications, they might work very well
and be an excellent alternative to drenching an organo-phosphate
or carbamate insecticide.
Weeds:
If you consider Poa annua to be a weed, we can report
here that summer heat stress decline of Poa is in full
swing; although it seems that most Poa is holding up fairly
well when compared to recent past hot summers (eg '99 and '01).
Of course we have quite a ways to go yet before this summer is
over. Complaints about moss and algae have subsided somewhat with
the dry and hot conditions we have seen, but recent rains and
high humidity (coupled with heat stress related thinning of turf)
may cause algae problems to reappear. Crabgrass and goosegrass
should be evident in areas where no pre-emergence herbicides were
applied (or in obvious misses or skips).
+++++++++++++++++++++++
The University of Illinois Turfgrass Field Day is scheduled for
Thursday, August 1st, and as part of the program a special
instructional seminar on the use and application of the InteractiveTurf
program will be held in the computer laboratory of the Agricultural
library on campus. This seminar/open discussion will be a great
opportunity to voice your opinion on the program and to steer
its development in a way that will most benefit your management
program. If possible, please make plans to attend.
Please keep us informed as to the health and condition of your
turfgrass in these hot, trying times. Drop us an email, fax
a pest alert, or give us a phone call to let us know what
is going on in your neck of the woods.
Randy Kane
CDGA
Director of Turfgrass Programs
Midwest Golf House
11855 Archer Ave
Lemont, IL 60439
630-257-8126
Lee Miller
CDGA
Manager of Turfgrass Research
Midwest Golf House
11855 Archer Ave
Lemont, IL 60439
630-257-2005 x.111
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