Spots and Rings
Weather:
The weather pattern
this summer has been a broken record of a few hot days tempered
immediately by a dropping cold front and resulting dominance
of a cool Canadian air mass. This has resulted in many days
with September or October-like temperatures, and temperatures
well below average. For most of the state, average temperatures
were 2-3 degrees below normal for July, and will be on that
same track by the end of this first week of August. This
leads me to wonder if we will ever get extended summer-like
temperatures here in northern Illinois, and going into the second
week of August I am starting to have my doubts. The forecast
through Sunday calls for no marked increase in temperature,
and the days are gradually getting shorter, so maybe this summer
will continue to be a mild one.
Rainfall totals
were a little higher than normal for much of the state in July,
although the rains were spaced out, so some drying out and water
stress problems may have occurred during lulls in the action.
This past Tuesday night's thunderstorms in northern Illinois
got us off to a roaring start for August, producing some locally
heavy amounts (almost 3 inches in Rockford) with most seeing
between an inch to an inch and a half.. What has been a story
through the last few weeks is the humidity which has led to
some pretty heavy morning dews and a pretty active fungus to
be named later.
Diseases:
The broken record continues to skip here in the
disease section as dollar spot persists as a weight around the
neck of most superintendents in northern Illinois. These fall-like
weather and conditions are just perfect for outbreaks, and application
intervals for fungicides are being pinched to their limit. This
makes skipping sprays nearly impossible, and trying to go with
an IPM strategy for managing fungicides very difficult.
In a year with this kind of severity, fungicide
rotation should be a priority (unless you are trying to go with
Daconil alone!). I am concerned that late season fungicide resistance
issues could develop, as fungicide use, and therefore selection
of resistant strains, has been necessary for the entire course
of the season. In some of our plots, we are starting to observe
fungicides that worked earlier starting to break down as the
season wears on, which could be due to this selection process
(since we apply the same fungicide over and over again on 14
or 21 day schedules).
Perhaps an even bigger issue, (if possible), than
the dollar spot is the increase of Type II (and down South Type
I) fairy rings on greens this year. What makes this a larger
issue is that fairy rings are very difficult if not impossible
to control with fungicides becuase there are a multitude of
fungi that cause them. One theory is that the rise in fairy
rings is attributable to the wearing off of previously used
mercuric fungicides. Whatever the reason, they are here en masse
this season.
Some
data from PACE labs in California suggest fungicide control
with a strobilurin (Insignia, Compass, or Heritage) or ProStar
can be enhanced by adding a wetting agent such as Primer or
Respond. As noted earlier, the problem is that the fungi causing
fairy rings there may be different from the fungi we are trying
to control here. If the fungicides are ineffective , masking
the rings with fertility or trying to core aerify and distort
the ring may be the only recourse.
I have also heard of guys trying to extract soil from two rings,
mixing it together and then putting the mix back in each of
the two dug out areas. The thought is that the fungi are antagonistic
and the next year will erase the ring pattern caused by the
dominant fungus. There are conflicting reports on whether this
works, but you would think that core aerifying and dragging
the plugs around would also work, and it obviously doesn't.
On greens, I would imagine this method would not be feasible
anyway especially if there are more than two rings.
Word through the grapevine is that some superintendents are
also trying Endorse, (which is labeled to have activity on other
basidiomycetes like brown patch and large patch), or a surfactant/solvent
called OARS (organic acid removal system). Neither Randy or
I have or can find any data that confirms or denies the effectiveness
of these treatments, so if you have tried them and have any
comments please forward them on to us.
I'll end it with some good
news: the anthracnose activity has tailed off at those sites
that reported it previously (Rockford, Bloomington, Moline).
Insects:
Pretty mild report, thank goodness. I haven't
heard near the problems associated with Japanese beetles this
year as I have in the past. The beetles that are around are
starting to settle down by now. Down south in Carbondale, however,
the first report of annual white grubs was made yesterday (8/4).
Those in St. Louis, Springfield and central Illinois should
be on their toes, and we should be at the ready soon with Dylox
or other spot treatment insecticides.
Cutworm reports are still coming in from all over,
which is normal, but I have not heard any sod webworm or other
insect problems over the last 2 weeks.
Moss and Crabgrass:
Same story here as well... The mild, moist weather
has caused many moss outbreaks on greens throughout Chicagoland.
Some success for moss problems has been reported with fungicides
such as Junction (copper hydroxide and mancozeb), Daconil, Dithane,
Fore, and Iron Sulfate, as well as the baking soda and Dawn
mixtures.. One notable tank mix for moss control supplied by
Wayne Otto (via Les Rutan@Crystal Tree) is Spotrete @ 4.5 oz/1,000,
Echo (90% A.I) @ 5.7 lbs/A, & Dithane @ 4 oz/1,000 applied
on a 2 week schedule. A lot of chemical, but some guys swear
by it.
Crabgrass is really starting to become a problem
throughout some areas of northern Illinois. We have had good
success with quinclorac (Drive) on some of our problem areas,
but fenoxaprop (Acclaim) is also reported to have good post
emergent control.
+++++++++++++++++++++++
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
