Spring has Sprung
Weather:
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First siting of a bluebird on the Sunshine Course
this year.
If he wants to wash equipment or hand water later this
season, than we'll let him have at it!!!
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A leak... Moderate temperatures and sometimes more than
adequate rains in late March and early April have greened
most courses in south Chicagoland and central Illinois.
March temperatures for O'Hare were right about on average
(+0.4 F) while March temperatures in Springfield and Carbondale
finally moderated (+2.7 F) after an incredibly warm (and
severe) start to the month. Our first bluebird was also
noted at Golf House on March 31, so get those birdboxes
out!
Rainfall amounts have been above normal for almost everyone
for the first three months of 2006, which has been a huge
relief on the drought situation that has been plaguing
north and central Illinois since last spring. Some areas
including Chicago and Moline are up as much as 2-3 inches
above normal for this time of year. The 10 day forecast
has Illinois squarely in the eyes of a few more storm
systems, with the Chicago rainfall forecast at 2.93 inches
over the span.
While the rains have been welcome, the severe weather
that accompanied it again in central Illinois was not.
Six confirmed tornadoes were reported in Springfield from
the storm on Sunday, April 2nd. Luckily, these tornadoes
were much more short-lived than the previous March 12th
disaster that hit there. In Carbondale, several other
tornadoes were reported but didn't touch the ground. Straight
line winds and microbursts were the problem there, making
a mess of tree limbs and anything else that wasn't bolted
down.
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Poa Seedheads
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Poa seedheads and timing of PGR applications are on
the minds of most as this new season is upon us. In
Carbondale, seedheads were first noticed around March
17 - 20 on higher mown roughs and became abundant on
greens on March 25th. The beat of the seedhead drum
has steadily rung up through the state and is now starting
to be heard as far north as south Chicagoland. The seedhead
to the left was found today after searching
a pure Poa annua stand on one of our tees at Golf House
in Lemont. A few other seedheads were found in rough
areas, making it a sure sign that Proxy/Primo treatments
should commence shortly.
Many in central Illinois (Bloomington, Peoria) and
south Chicago are putting out the first application
of Proxy/Primo today or tomorrow. This application timing
makes sense to catch the seedheads in the booting stage
and control the initial flushes. Applications a little
later (i.e. next week) may not catch the entire initial
flush but will still do a decent job in reducing seedhead
numbers, especially after the second application in
May. Remember that Proxy/Primo is not a 100% cure, at
best it gets 80-90% of seedheads suppressed. Embark,
which is the gold standard as far as suppression goes,
is ticklish as far as the amount of phytotoxicity it
imparts, particularly on greens height turf. For this
reason, some superintendents like to put Embark on fairways
and Proxy/Primo on greens.
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To cut into the phytotoxicity issue, I have heard
of a superintendent or two that are breaking up Embark treatments
into 3 - 1/3rd label rate applications separated by 7-14 days.
They say that green color and phytotoxicity is no longer and
issue and superior seedhead control is achieved. I haven't seen
it, nor would I necessarily endorse off label applications,
I'm just reporting what I heard.
Several theories or methods
exist for trying to adequately time PGR applications for Poa
seedhead suppression. One method of timing the first application
is to treat after the second mowing, since both Proxy and Primo
(and also Embark) are foliar absorbed and work best on green
actively growing tissue. Therefore it doesn't make much sense
to be treating brown grass, and waiting until the turf is green
and has been mowed a couple of times is sensible. Other phenology
related timing methods include watching for the forsythia bloom,
or spraying when Poa seedheads start forming in the roughs on
a south facing slope.
Degree day accumulations
are also used as basic phenology predictors of weeds and insects.
On the Illinois map below, a new model for Poa seedhead is shown
as of April 2nd based on base 32 degree days. Keep in mind,
that by April 4th these colors would have shifted up the state
even more, but according to this new model (which is described
in further detail below) the first Proxy/Primo application should
be made in south Chicago and central Illinois and definitely
needs to be made (orange color) in Quincy, Springfield, Champaign,
and Decatur if it hasn't been done yet. The red color in southern
Illinois indicates the best timing is now for Embark
applications.
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Degree Days through April 2nd
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New Model: DD32 - As
of April 2nd
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Location
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DD32
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DD50
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| Glenview |
181
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13
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| N. Barrington |
183
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10
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| Lemont |
214
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11
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| Aurora |
229
|
12
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| Bloomington |
298
|
30
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| Peoria |
310
|
31
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| Carbondale |
519
|
150
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Degree Day accumulations
through April 2nd. Both base 32 and base 50 degree days are
shown in the table on the left. Researchers at Michigan State
have further refined the Poa seedhead prediction model and are
now using one based from the base 32 degree days. Model colors
shown reflect relative alert levels in the two tables below.
Interactive Turf formerly
used a base 50 degree day (DD50) system to characterize
the development of Poa seedheads. This method is now antiquated
as the Poa gurus at Michigan State (Dr. Ron Calhoun et al.)
have refined the model to a base 32 degree day (DD32)
system as outlined below. Using DD32 has many advantages
over our current system. For one, DD32 characterizes
the metabolism of Poa much better than a DD50, because as
part of Poa's competitive advantage it naturally greens up at
much lower temperatures than other cool season grasses. Secondly,
we don't have to worry about resetting DD32 to zero
when a "hard freeze" occurs -- which was never adequately
defined in the first place.
The new system also recommends
actions more solidly. More detail (through more research) has
been put into the actions recommended at the appropriate DD32
range (which is conveniently every 100 DD32
after 200 is reached). At Michigan State, every Proxy/Primo
application past 309 DD32 resulted in less and less
effectiveness for catching the earlier seeding biotypes. So
the range of 200-300 DD32 is the span for the first
Proxy/Primo application, and 300 - 400 DD32 is prime
time or even getting a little late. Likewise, the first Embark
treatments are also timed with this system, as 400-500 DD32
is the target range for applying with the most effectiveness
and least phytotoxicity. See the tables below for the old and
new model descriptions.
Old Model
Using Accumulated base 50 degree days
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Alert Color
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DD50 range
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Action recommended
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Yellow
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10 - 24.9 DD50
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Start scouting for seedheads in rough areas,
and southern facing slopes |
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Orange
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25-60 DD50
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Proxy/Primo applications can start being made
at this time. |
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Red
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60.1 - 120 DD50
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Seedheads should start popping on the earliest
flowering biotypes. |
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* Degree days reset if a hard freeze
occurs (low temp < 32 F) and DD50s < 50.
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New Model
Using Accumulated base 32 degree days
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Alert Color
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DD32 range
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Action recommended
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Yellow
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200 - 300 DD32
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Best timing for 1st Proxy/Primo application;
Follow up application should be made 14 days after if using
3 - 3 oz Proxy + 1/8 oz Primo / M applications, or 21 -28
days after if using 2 - 5 oz Proxy + 1/8 oz Primo / M applications.
Primo rates should be increased to 0.2 - 0.25 oz / M for
fairway applications |
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Orange
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300 - 400 DD32
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After the first few "orange" days,
this is getting late to catch the initial flush of seedheads
with Proxy/Primo. Subsequent applications will still work,
but some early breakthrough should be expected from the
earliest seeding biotypes. |
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Red
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400 - 500 DD32
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Embark application should be made
to obtain maximum seedhead control with the minimum amount
of turfgrass injury. Early seeding biotypes should be flowering
at this time. |
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* Degree days start accumulating on March
1st.
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Diseases
Had enough about Poa seedheads and degree days?
Pink snow mold breakthroughs are still being reported around
northern Illinois, especially for those that used covers over
last winter. The covers, of course, produce a perfect little
microenvironment for pink snow mold. Warm, moist, and higher
humidity levels under the covers make it a perfect incubation
and infection environment for the pathogen. Clean up applications
should be made for this disease, since it will remain active
as the spring wears on and even "morph" into its sister
disease of Microdochium patch. Contact applications like chlorothalonil
should stop it cold, but adding a systemic like iprodione or
a strobilurin should provide longer protection. For the most
part, Rhizoctonia cerealis has faded off into the sunset, so
the Rhizoctonia zeae rings should be starting up in the next
few weeks to a month.
For those curious about early dollar spot applications,
I still believe it to be too early in the Chicago area based
on last year's study. For those in central and especially southern
Illinois however, the time could be right over the next few
weeks to take some preemptive action. Carbondale in particular
at 150 DD50 (sorry I guess I wasn't done with those
yet!) is probably right in the window of when an early application
would limit the first wave of dollar spot outbreaks.
-- Other Interesting Tidbits
- No news on the cutworm front, but I would expect
traps in southern Illinois to start catching some soon.
- The preemergent window for crabgrass applications
is upon southern Illinois now. I told you spring was coming!
- Interested in Integrated Pest Management (IPM)
for the trees and ornamentals at your site? Interactive Turf
now has a counterpart called VirtualArborist which can inform
you when it is time to inspect your plants for pests. This new
service maintains an inventory of trees from your golf course
to notify you when a specific pest is likely to present itself
on a particular host. Treatment opportunities are listed by
host species, making it simple to inspect and monitor for potential
problems. Phenologic indicators and degree days are used as
predictors of outbreaks. Since trees are such an important asset,
and with the average cost of removing a single tree exceeding
$1,000, this service makes a lot of sense. There are even links
to other web sites, making it easy to educate yourself on pest
identification and the latest in pest treatment alternatives.
For more information, go to the web site: http://www.VirtualArborist.com
and leave a message on the contact form.
+++++++++++++++++++++++
Thanks for your support of this, as well as all
of our research programs,
Lee
Miller
CDGA
Manager of Turfgrass Research
Midwest Golf House
11855 Archer Ave
Lemont, IL 60439
630-685-2305
Derek
Settle
CDGA
Manager of IPM Programs
Midwest Golf House
11855 Archer Ave
Lemont, IL 60439
630-257-2307
