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Rhizoctomania
Wx Review:
Summer made a brief appearance in Northern Illinois the past
few days, but will it last? In the span of a week we have gone
from 10-15 degrees cooler than normal to 10-15 degrees warmer
than normal, now back to the cool side - a typical late spring
pattern for the upper Midwest. Air temps reached the mid to upper
80s on May 30-31, and topped out at 91-93 F on June 1. Soil
temperatures have risen steadily over the past few days and have
passed the 70 degree mark for the first time this year in the
Chicago area. The weather pattern has been similar in central
Illinois, a few degrees warmer overall but with the same switch
from much colder than normal to hotter than normal conditions.
Air temperatures surpassed 90 degrees on May 31 and June 1.
Certain types of bentgrasses and Kentucky bluegrasses (Midnight
types) were off color and slow growing during the recent wet and
cold weather. The warmer weather of the past 7-10 days has contributed
to much better color and improving densities for most of these
grasses. Poa annua flowering and seed formation is starting to
decline, especially for the heavier seeding
biotypes (annual type). Some Kentucky bluegrasses have gone into
heavy flowering mode as of late, and perennial ryes and other
taller turfs that set seed are now starting to flower as well.
Disease update:
Following the heat of the last few days, reports of Rhizoctonia
and related rings and patches have increased dramatically. Symptoms
are primarily an expanding ring of yellowed Poa annua, and are
most likely caused by the fungus Rhizoctonia zeae. The
fungus thins and weakens Poa as it grows out in a ring shape,
but usually doesn’t cause permanent harm to infected plants. Bentgrass
is not affected, and patches of bent can cause a ring to appear
broken or as semi-circles or arcs. Some of the rings affecting
Poa may also be related to the Pink Patch disease organism (Limonomyces),
or other fairy ring causing basidiomycetes. More
information on Rhizoctonia patches appears on the InteractiveTurf.com
website.
During the cool, wet weather of the past two weeks, there were
some reportsof Microdochium patch; see
previous active pest report on the website for symptoms. However
with the recent warm-up, most of the Microdochium patch
symptoms should clear up on their own. Cool, wet spring weather
also favors the appearance of take-all patch on creeping bentgrass,
and we have seen some activity of this disease over the last few
days.
Last week’s warm and humid weather gave some early dollar spot
symptoms time to develop. Most spots were very small (dime size
or smaller) and little aerial mycelium was noticed. Don’t forget
that those cobwebby-looking white patches that catch the early
morning dew may be spider webs and not dollar spot fungal activity.
However, it is definitely time to start scouting “hot spots” or
old dollar spot scars for signs of activity, and it will soon
be time to apply the first preventive/early curative dollar spot
treatments for summer. (Dollar spot is very active as of 6/10
- see home page).
Short duration weather patterns with high heat index/relative
humidity ratings can trigger warnings from computer models for
Pythium blight and brown patch (Rhizoctonia solani), but
this early in the year there will be little development of these
mid-summer pathogens, although there are some reports of brown
patch from Central IL in the last few days.
Insect update:
Most recent insect complaints have centered on finding small
insect feeding holes on greens and some bird/skunk feeding damage
in roughs. Some black cutworm larvae have been found in central
and northern Illinois. Also, a report from the Univ. of Illinois
‘Pest Management and Crop Development Bulletin’ has noted some
increase in black cutworm activity in western
Illinois field corn – so apparently these buggers are out there
(two active cutworm reports in Chicagoland on June 8th). Adult
beetles are starting to appear, including adult Ataenius crawling
around on greens, and adult June beetles and masked chafers collecting
around outdoor lighting at night. More than the usual numbers
of these grub species (as well as Japanese Beetles) may have survived
the mild winter, and it could be a banner year for damage from
the next generation of grubs...
Weeds:
Now is probably a good time to try to control some tough broadleaf
weeds (e.g. thistle) around ornamental planting beds and unmowed
(naturalized) areas. One herbicide that has had some good activity
is clopyralid, which is one of the two active ingredients in Confront
(the other is diclopyr). Clopyralid alone is sold as Lontrel,
which has some selectivity on woody plants and grasses – be sure
to read and follow the label to avoid non-target phytotoxicity.
The battle against moss invasion of greens continues. We have
some test plots out comparing the activity of a dish soap (Dawn
Ultra), Terracyte (sodium perchloride + lime), and Junction (Mancozeb
plus copper hydroxide). Soaps and wetting agents appear to knock
the moss back with each application, but it will probably take
multiple apps and some diligence to get rid of the moss this way.
Junction may be abetter alternative long term, although you have
to monitor the copper accumulation in soil, which can inhibit
root growth (mostly of Poa annua).
IT Update:
The new website has been launched, as we have migrated to a web
server that can better handle database capabilities. We expect
some growing pains, one of which will be the differences between
your computer browsers and settings, and their impact on the scripting
of the site. As the site opens, please pardon our dust for a while
as we work to fix these bugs and bring you these improvements.
Look for a username and password to enter the member portion
of the site in your email (you must have found it to be reading
this). This part of the site will be the most up-to-date information
on turfgrass pests in Northern and Central Illinois, (St. Louis
too), and will include both pest reports submitted by you, and
generated forecasts (alerts) based on current pest prediction
models.
(Please note change in language here. To avoid confusion, "active
pests" will be the phrase used to denote reported pest activity,
and "pest alerts" will be used to indicate a pest forecast
period.)
Forecasts are displayed on a calendar with color-coded significance
levels, and will migrate to a map format in the future. In either
case, you are able to see how weather conditions may be influencing
pest activity in your area, whether or not you are sending us
weather data.
(Please note that on the website you can see how far you
are away from a weather collection site (generated pest alert)
and direction.)
If you are sending us weather data, then you are seeing the fruits
of your daily labor. Predictions are based from the weather data
collected directly from your site, and this, in conjunction with
your submitted reports of pest activity, will be an invaluable
tool for us to build an effective IPM program.
Several weather stations that are providing important regional
weather data have been installed at the Midwest Golf House, Cantigny
C.C., and Prestwick C.C. If you are interested in installing a
weather station at your course for irrigation and IT/IPM purposes,
please contact me so I can help with the process and preserve
consistency among program data.
Thank you for your continued support of the program, and, we
know you are sick of hearing this, but please send us your active
pest/scouting reports. They are the most important cog for us
to most effectively model pest activity in the future.
Randy Kane, PhD
630-257-8126
rkane@cdga.org
Lee Miller
(630) 257-2005 x.111
lmiller@cdga.org
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