C'mon Hump Day !!!!
Weather
The drought and heat that northern and some
of central Illinois (most notably around Peoria) are still
engulfed in has been brutal. Affected areas are 7-9 inches
below normal precipitation after a July that saw many areas
in northern Illinois only get 50% of their normal precipitation.
Conversely areas in southern and central Illinois, like Kankakee,
got much more rainfall in July, downgrading their drought
status to a moderate level and bringing the overall Illinois
precipitation average to near normal. Even with July's near
normal rainfall, the entire state of Illinois got just 11.83
inches of rainfall or 58% of normal from March 1st - August
10th, the 5th driest period recorded since 1895.
(Click here to see the last newsletter
which details some hints on watering).
July temperatures were less brutal than June,
but not by much. The average July temperature was 2 degrees
F above normal, whereas June's was 6 degrees F above. This
leads to an average of 4.4 degrees above normal for the period
of June 1 - August 15, and an astounding 30 days where the
high temperature eclipsed 90 F (- all stats from O'Hare
NWS data). Remember last year, we only had 3 days above
90F. Degree day accumulations have also been way up as compared
to last year at this time, evidenced by the table below.
|
2004 vs. 2005
Degree Day Comparison
|
| |
July 6th
|
August 16th
|
|
Location
|
2005 DDs
|
2004 DDs
|
Differential
|
2005 DDs
|
2004 DDs
|
Differential
|
| Peoria |
1596
|
1530
|
+ 66
|
2769
|
2386
|
+383
|
| Bloomington |
1513
|
1497
|
+ 16
|
2633
|
2330
|
+ 303
|
| Naperville |
1277
|
1155
|
+ 122
|
2347
|
1913
|
+ 434
|
| Aurora |
1265
|
1227
|
+38
|
2342
|
2014
|
+`328
|
| Rockford |
1203
|
1123
|
+ 80
|
2074
|
1845
|
+ 229
|
The impact this heat has had on the root system of
our cool season turfs cannot be ignored. Average soil
temperatures at 2 inches in a native soil (!) were close
to 80 degrees into the first few weeks of August. Normally
a sand root zone runs about 5-10 degrees higher than
a native, which translates to near 85 or 90 F averages
and close to 95-100 degree soil temperatures during
the height of the day! Poa, bent and even Kentucky bluegrass
roots were definitely crying uncle.
Some needed rains gladly hit much of northern Illinois
late last week (of course, just in time for the Walker
Cup matches at Chicago Golf Club). Rain totals varied,
with most areas getting about 3/4 to an inch and localized
areas getting up to two inches out of the event. Although
it seemed to be a drought breaker, in actuality it was
far from it. August is typically our wettest month,
with an average of 4.62 inches of precipitation, so
we still have a ways to go at the midway point before
the average is even met in northern Illinois.
Many superintendents are talking a lot about hump
day in its non-risque connotation. Hump day in a regular
work week is Wednesday, because if the week were looked
at as a hill, then once you reach Wednesday it would
be all downhill until you reach the end, or Friday.
In the growing of cool season turfs, (where regular
work weeks in the summer definitely don't apply), hump
day is when most think the hot summer is over and cool
season turfs start to recover and grow healthily again.
In Chicago, this hump day is thought to be August 15th,
when there is less daylight and cooler temperatures
start to arrive. Although Chicago averages another 3
days of high temperatures above 90 F, the impact is
lessened by the shorter days and longer period of darkness
when temperatures are moderated.
Most believe that the hump day of August 15th will
have to be pushed back a bit because of the difficult
summer we have endured thus far. BUT -- finally I get
to write a little good news - - the forecast might be
saying differently. If the forecast holds true, northern
Illinois is set to get some more needed rain today (Thursday)
and then a short surge of heat and humidity on Friday
(which will NOT be good for turf). However, a Canadian
high pressure mass is set to descend over the Midwest
shortly thereafter, meaning temperatures on Sunday and
Monday of next week might only reach 75 F, with some
lows in the 40s possible. Reseeding of problem areas
can probably be started at any time now with a good
chance of success.
|
Diseases
Rhizoctonia has been the word around
town for the past two weeks. Conditions lately, especially
with last week's rain, have been perfect for it. Rhizoctonia
symptoms, however, have been atypical this year. We have seen
many instances where it hasn't been the classic brown patch
we're accustomed to during the summer. Rather symptoms have
often been a scalloped or thin diseased ring, or tufts of
mycelium that can closely resemble Pythium (see
picture below). We have also consistently isolated a different
species of Rhizoctonia, R. zeae instead of R
solani. This species is normally responsible for the yellow
ring symptom we see on Poa during the spring and fall,
but curiously in the southeastern US is the cause of a high
temperature (>90 F) form of brown patch. It is possible
that it has been so hot this summer that this species of the
pathogen is predominating in the population as well as R.
solani.
Tufts of Rhizoctonia mycelium that could be easily mistaken
for Pythium.
Dollar spot has also been a problem, but has
been most severe on untreated Kentucky bluegrass roughs as
of late rather than on treated bentgrass areas. Two reasons
for these outbreaks on bluegrass, which we normally see towards
the end of the summer season are: 1) a lack of nitrogen (used
up from a spring application) and 2) the bluegrass is not
growing as fast because of the stressful summer it has endured.
For the most part, fungicide application is not recommended
unless the outbreak is especially severe. An alternative could
be to give the roughs a small shot of nitrogen since the forecast
looks favorable for early next week. We do expect our usual
fall outbreak of dollar spot on shorter cut bentgrass areas
very soon.
Summer patch on Poa annua and pratensis
has flared up considerably over the last few weeks.
The heat has also brought out symptoms of summer
patch in the last week or so. Irrigated bluegrass roughs,
especially near collars or other high traffic areas, are burning
out (see picture above). Poa annua on greens, which
has had enough trouble already, is also turning chlorotic
and dying in distinctive summer patch circles. Treatment strategies
at this point are quite limited, but our recommendation would
be to treat greens if needed with propiconazole (Banner) or
azoxystrobin (Heritage) either with 5 gallons of water/ 1,000
sq ft or lightly watered in with 1/8 inch of water. Both of
these fungicides have been found best for curative summer
patch control in studies at the University of Kentucky. For
roughs, overseeding burnt out areas with a little perennial
rye in the blend might be the way to go.
The "New" Malady Section
In a year like this one, heat can be pretty
detrimental to the fragile workings of a C3 cool season turf.
Heat also can activate normally saprophytic or slightly parasitic
fungi and make them pathogenic or abundant enough to outcompete
the turf for nutrients. This in effect can be the straw that
pushes the plant over the edge and make it symptomatic, oftentimes
in ways that we have not experienced before. For the most
part, when temperatures moderate and the turf starts growing
vigorously again, the symptoms tend to subside. With that
preface, we have seen several symptoms this year that we have
not been able to fully explain yet, (and frankly the curiosity
is killing us).
Whitish patch of unknown origin, usually
smaller in the first year and grows in size.
The first of these is what we had been previously
referring to as white patch, or a high temperature, superficial
form of fairy ring (see picture above). Although this
previous diagnosis may be correct, we have started to isolate
suspicious looking root fungi from some of these infected
plants - the kind that either cause take all or summer patch.
This in itself doesn't necessarily equate to a confirmed diagnosis
however, so further isolations are being made. The patches
could also be caused by the Pythium species that has been
characterized recently in North Carolina, but the symptoms
aren't nearly as severe and we have seen no signs of that
pathogen yet. Luckily so far, when temperatures subside. these
patch symptoms do as well.
Left: Symptom from alleged Glomus
Right: Gumming up of thatch layer on right.
Put cursor on right picture to see what we are observing
in gummed up that layer.
The second of these maladies we first saw last
year, and have seen once again this year. The two courses,
one in Chicagoland and the other in Bloomington, were newly
renovated greens that had been treated with methyl bromide.
A thick mat of fungal biomass seems to be accumulating in
the thatch layer, and smelling as Randy puts it like wet,
fishy dog food (see pictures above). This mat seems
to cause symptoms by either raising the turf enough so it
scalps, blocking up the pore space so water and nutrients
can't seep through, or clogging up and damaging the roots'
vascular system. The fungus we believe we are seeing is a
Glomus species which is normally thought of as a beneficial
mycorrhizae species. In this case, however, we think the Glomus
is a "mycorrhizae gone wild" perhaps because there
is little competition by other fungi in this sterilized root
zone, and the fungus is just a little too "happy".
Similar to an algal bloom, the fungus gets out of control
and erupts a multitude big (in relative terms) spores from
the roots it inhabits, perhaps damaging root cells and in
turn the plants.
Symptoms of another unknown disease. Note
light chlorotic spots that eventually thin out and die.
Another of these new problems we've encountered
this year, (one many of you have already heard about), is
again on a newly renovated green treated with methyl bromide.
At first, we thought the symptoms looked very similar to the
alleged Glomus problem - light yellow spots (2-3 inches in
diameter) of bentgrass that gradually turned necrotic (again
see pictures above). However, the thick mat layer of fungal
biomass associated with earlier outbreaks was not present
(although some limited Glomus could be seen in deeper roots).
Symptoms also seemed to proceed quite quickly and the green
became speckled with spots of necrotic grass in a few days.
To this point, we honestly have not been able to make an accurate
diagnosis, but it may be a species of algae that produces
a toxin to the plant.
I've gotten some comments from those thinking
of renovating that they are worried about using methyl bromide
on greens because of these new symptoms. Well, I believe there
would be a lot more problems with grow-in and establishment
if methyl bromide were not used. Besides you better use this
particular tool while you've still got it, because at this
time there isn't a viable and effective option.
Insects
Small annual white grubs have been noted in
an untreated soil at a course in northern IL, so there probably
was enough Japanese beetles or masked chafers around to give
us a significant enough grub population in irrigated turf
areas. These untreated areas may become problem children as
these grubs grow up and either start chomping on turf roots
or end up getting chomped themselves by scavenging skunks
and 'coons.
Left: Bagworms chomping on a crabapple
leaf.
Right: Bagworms totally defoliating the top of this spruce
at Golf House.
Like last year, bagworm damage is becoming a
problem on trees at some sites, including Golf House (see
pictures above). This year, however, the bagworms seem
to be concentrating their efforts on spruces and junipers
rather than on the young crabapples that we saw last year.
This critter makes a protective shell around himself of silk
and tree leaves, and just reaches out his mouthparts to eat
on the leaves and stem parts. Once fully infested, picking
all of them off is impractical, so some have gone with an
insecticide like Battle or Sevin to knowck back their numbers.
Bird pecking damage has continued throughout
Chicagoland steadily for the past month or so. This is actually
biocontrol at its finest, although the grass is suffering
some damage because of it. Most of the activity has been limited
to tees and fairways, where insecticide applications for cutworms
and other foliar feeders have not been made. Control options
to minimize the bird damage are Deltagard, Dylox, or other
insecticides that attack foliar feeding insects. Previously
applied Merit will not work because this is not a grub problem.
Even the insecticides listed above may not work very well
if the cutworms are in this pupal stage because they are not
actively feeding. We are observing cutworm and sod webworm
feeding activity in several areas though, so it seems like
we are stuck in the middle of a few generations of these insects.
Weeds
There has been a bumper crop of crabgrass this
year. The picture above is on our low-mow Kentucky bluegrass
plot here at Golf House. We really did this on purpose, (at
least that is what we tell everyone), to see which variety
does the best job of crowding out weeds. At this point, post-emergence
herbicides like Acclaim, Drive or Dimension are the only options.
There are some differences between these post-emergents that
should be noted. Acclaim doesn't work well in drought conditions,
can cause discoloration to bluegrass, and is not as effective
when the crabgrass is at a mature stage. Dimension's post
emergence activity actually leads to a longer window for applying
in the late spring early summer as it doesn't work very well
past an intermediate stage of crabgrass. That leaves Drive,
which has a niche as working best on mature stages of crabgrass.
It should be applied when the soil is moist, but should not
be irrigated or rained on for at least 6- 12 hours after application.
To read more postemergence crabgrass recommendations, click
here for a great article in Turfgrass Trends written by Dr.
John Street from Ohio State University.
++++++++++++++++++++++
Thanks for your support of this, as well as
all of our research programs,
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.106
