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Newsletter |
Spring Recovery
Weather Update:
We picked up another inch plus of rainfall this
week (mostly May 19-20) as temperatures remain a little cooler
than normal. Recent daily highs have been in the low to mid 60s
in northern IL with overnight lows dipping into the mid to upper
30s. Temperatures have been slightly warmer in the central part
of the state, but still a little on the cool side. Some light
to moderate frosts have been reported in Chicagoland for May 21
and 22. Also, we have noted several days where morning to midday
soil temperatures have been higher than the air temperature -
which is good, because it keeps the microbes and roots actively
growing (we hope!).
Hopefully the 5 to 6 inches of rain most of us received in
May has taken some drought stress off of turf, shrubs, trees and
other plantings. Below normal temperatures are probably keeping
some pest activity at bay for now, as well. Most off color or
thinned turf has recovered from winter injury, but severely damage
areas will be slow to recover with the cool temperatures. Also,
cool temperatures are slowing seed germination in areas that have
been overseeded. (for more information see "Winterkill
on Poa Annua - Spring 2003" in the turfgrass section
of the CDGA
website, or "Is
Recovery Just a Spray Away?" by Bob Vavrek,
USGA agronomist.
Diseases:
We have seen some initial dollar spot activity in
fairways in the Chicago area, and have received some reports of
stronger activity in central and southern Illinois. The dollar
spot pathogen can be slowed by cooler temperatures but can remain
active. Also, there is ongoing research concerning a strain of
the dollar spot fungus (Rutstroemia floccusum) that is
active at much cooler temperatures (maybe why we see some serious
damage in autumn). Be sure to check the dollar spot model output
for predicted disease activity in your area. Staying ahead of
dollar spot outbreaks with preventive or early curative fungicide
applications may be crucial at some sites to prevent damage that
will recur throughout the summer season.
Early symptoms of take-all patch have been observed at a couple
of northern IL courses, primarily on sites that have had the disease
in previous years. The take-all pathogen (Gaeumannomyces graminis
var. avenae) is active at cool soil temperatures when moisture
levels are high. However, symptoms of infection usually do not
appear until the first warm, dry days of early summer (generally
early June in northern IL). Also, take-all patch usually occurs
fairly early in the life of a bentgrass turf (first 5 years or
less), and the disease often lessens in severity as the turf ages.
Take-all patch, summer patch and other patch diseases caused by
root-rot fungi are very difficult to control with fungicides,
and curative treatments rarely provide any improvement in symptoms.
Preventive applications of DMI and QoI fungicides can alleviate
patch symptoms in many cases, if the applications are made at
optimal soil temperatures in mid to late spring. For take-all,
we generally recommend treatments when soil temperatures first
range into the low 50s F (which has or is happening in most areas),
with a followup application 21-28 days later. For summer patch
on bluegrass, applications should be made when soil temperatures
get into the mid to upper 60s F, (which hasn't quite happened
yet in central and northern IL). In general these are early to
mid April applications for take-all patch, and mid to late May
applications for summer patch.
Weeds:
Seeding of Poa annua is probably at, or just
past, peak density in northern Illinois. Many superintendents
who are using Proxy tank mixes for seedhead suppression are reporting
good to excellent results. We have noted as much as 70-80% reduction
in our plots again this year. We are also looking at the effects
of a second application of growth regulator in mid-May, and will
follow the status of those treatments until late June.
Moss growth is now becoming more evident in infested greens, and
many queries are again coming to us for possible moss control…
We still have no good answers; some superintendents report initial
success with fall applications of Junction (copper hydroxide plus
mancozeb), while others continue to have some success with Terracyte
or Dawn dish soap. If moss is a chronic problem, you can probably
blame one or more of the following turf conditions: low mowing
heights, low N fertility, low K fertility, high Ca levels or high
Ca/Mg ratios, moisture held in/near thatch by mini perched water
table (probably from sand topdressing practices)… Take a close
look at how your greens are managed and try to correct potential
cultural problems…
Insects:
Over the last week, some significant cutworm feeding
activity has been reported in central Illinois and starting up
in southern Chicagoland (below I-80). The first cutworm siting
was noted in central Illinois on April 30, which coincided with
"intense" cutworm moth captures that also occurred on
that date. Now, three weeks after the first worm, our first real
"flush" of cutworm activity is on in the central region.
In a past newsletter and pest report, I proposed using "the
corn cutting" model as possible prediction for our feeding
activity on our turf. The model is below, and although it didn't
predict the first cutworm siting correctly, it seems to be reasonably
close for the flush of activity that is being seen in the central
region right now.
Adult May and June beetles are flying around the
front porch light and falling into the mailbox - I guess they
survived the northern IL winter after all.. We will see if there
are Japanese beetles doing the same in a few weeks. Mound building
ants have been quite active recently, and there may be some other
insects active in sand on greens and tees (possibly sod webworm???)
+++++++++++++++++++++++
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.111
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