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Summer Is Upon Us
Weather Review:
Summer weather conditions have arrived with the summer solstice.
Recent hazy, hot and humid conditions are expected to continue
at least through the middle of next week. Temperatures across
the state are expected to range from the low to mid 90s during
the day, while cooling down to the low 70s at night. Dew points
are expected to stay fairly high, in the 65-70F range,
which means that heat index readings will be in the upper 90s
to near 100 during the heat of the afternoon. This is our first
hard shot of summer heat for 2002, and the typical turfgrass problems
are expected to arise: high temp diseases such as Pythium
blight and brown patch, fairy rings, and localized dry spots may
become active soon. Check out the
Pest Alert predictive section of InteractiveTurf.com to see
how the disease/pest prediction models are faring.
Diseases:
Several diseases have been active for the past week or two -
primarily dollar spot,
take-all patch,
and the Rhizoctonia
related yellow rings (all of these problems have been summarized
on the website). Take-all patch symptoms will probably peak during
this hot spell, and typically will subside later in summer as
the infected plants recover and new shoot/root
growth replaces injured tissues. The yellow rings in Poa annua
caused by Rhizoctonia zeae also typically clear-up once
we have some cycles of hotter weather. Some of the very severe
yellow rings we observed a couple of weeks ago on Poa fairways
are now totally gone.
In the last couple of days, we have also seen much more activity
related to fairy rings and localized dry spots (LDS). Both problems
commonly start to show up in late June with summer heat and humidity.
Fairy rings are caused by fungi that decay thatch and organic
matter in the turf, while the causes of LDS are not well defined,
but in some cases appear to be related to the activity of thatch
decaying, fairy ring type fungi.
There are also continuing reports of basal
stem rot anthracnose, which is caused by the fungus Colletotrichum
graminicola. In most cases, the disease affects only Poa
annua, and does not thin or weaken creeping bentgrass in an
infected turf. Anthracnose symptoms often begin with scattered,
small yellow to copper colored spots on Poa about the size
of a dime. As these affected areas enlarge, you may see creeping
bentgrass expand into a thinned area, which gives a very distinctive
look to the symptoms. Other diseases that will cause this type
of expanding bentgrass patch with dying Poa around the perimeter
include summer patch and necrotic ring spot.
(NOTE: Click here to see a list
of Recommended Fungicides for selected diseases.)
Insects:
As the weather warms up and we accumulate growing degree days
(approaching 1000 in Central IL), insect pests on turf and ornamentals
become more active. We have seen quite a bit of injury from
black cutworm larvae on greens and tees over the past two
weeks, and this will continue on and off through the season. Although
it seems a little early, we have also found
some Ataneus grub activity. The grubs had caused enough root injury
to show symptoms on the plants, but animals were digging up the
turf in infested areas (probably a skunk!).
Japanese beetle grubs have been observed causing some damage
in fairways of late; these bad boys will soon pupate and turn
into those adult,
shiny green, Linden-tree-eating-machines we look forward to
in summer. It could be a banner year for JB injury because of
the mild winter following some locally heavy infestations and
observed damage this spring from overwintering grubs. There are
scouting reports of emerged Jap beetle adults feeding in southern
Illinois and Indiana over the last few days. For more information
on insect activity statewide, check out the U
of I’s Home Yard and Garden newsletter and the Pest
Management and Crop Development Bulletin.
Weeds:
It was a banner spring for white clover, dandelions, and other
cool season broadleaf weeds. Now that the summer weather is here,
we will start seeing some of the warm season weeds, especially
crabgrass, goosegrass, and yellow nutsedge. Clover and these weedy
grasses can be controlled with post emerge herbicides. Keep in
mind, however, that there are problems with using herbicides in
hotter weather. Such as . . .
- Greater chance of phytotoxicity on desirable turf (like
bentgrass)
- Reduced herbicide efficacy at controlling target weeds
- Potential tip burn or worse can be caused by many chemical/dish
soap attempts at moss control
So be careful out there!!
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Be sure to check the website frequently for pest alert computer
model predictions, informational updates, and active pest bulletins.
Also, keep in mind that WE NEED FEEDBACK concerning the
pests and other turf troubles that you are seeing at your site.
Send us an email, or click on the submit
pest alert link on the homepage and let us know what’s going
on out there…
remember the program is called “Interactive Turf!”
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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