Weather review
September has arrived and right on cue so has the cooler
temperatures (and the aerification holes). The Labor Day weekend
brought a strong cool front that dropped drenching rains on
central IL and southern Chicagoland (2-4 inches locally),
but let very little precipitation on those nearer the Wisconsin
border (just over a tenth in some areas). These rains put
a damper on potential revenue that could have been garnered
from this holiday weekend, but did the turf some good as most
places were running a huge deficit in normal rainfall for
August.
In the cool front's wake, a strong high pressure dome has
dominated the area leaving us cooler air for most of the week.
The forecasters are calling for steady sunshine and a steady
increase in temperatures throughout the weekend and into early
next week, but still only in the mid 80s for highs. The areas
that didn't get the rain last weekend will probably have to
wait until late next week, as only a very slight chance for
rain exists on Monday.
Diseases
The cooler weather and HEAVY dews that have occurred this
week have favored dollar spot development. This is consistent
with the normal disease severity cycle that occurs for dollar
spot through the season: high in May/June, lower in the hot
months of July/August, and high again in September/October
(see graph below). In the past 48 hours, a number of dollar
spot reports have come at sites where the protective interval
of a preventative fungicide application was at its limit.
Like last year, we will be investigating possible fungicide
resistance cases by running screens of local dollar spot samples.
If you have any samples you would like screened give Randy
or I a call.
Another disease that is primed by cool weather
and ample moisture is yellow tuft, which we noticed this past
week at the Midwest Golf House Short Course. Yellow tuft symptoms,
caused by a downy mildew fungus, are noticed as yellow spots
that consist of 1 or 2 plants that may have 20-30 or more
yellow tillers. Roots of the infected plants are short and
the tufts can be easily lifted from the turf. Seedlings or
younger stands, like ours, are most susceptible to infection.
Yellow tuft is mostly a problem on greens where it can look
like Poa invasion, and in severe cases can be controlled chemically
with Pythium fungicides such as Alliete or Subdue. One area
superintendent's program consists of spraying twice preventatively
in late spring, and mid summer to control symptom expression
that may occur now in the early fall. Otherwise, he says,
the members will ask him what he is going to do about all
the new "Poa"!
Insects
Japanese Beetle adult activity has peaked in most of the
state. It appears that JB populations have been much lighter
this year than in recent past, but some areas were still pretty
hard hit. Hopefully, like the beetle population, the white
grub population will also be less than normal this year. White
grub activity has not been reported yet, but should be expected
and scouted for in early September.
Cutworms and sod webworms remain active and will continue
to be a problem for a few more weeks (as are the feeding birds)
on untreated areas. Mound building ants are an ongoing problem
as well, and we still seem to be searching for an effective
treatment – especially on greens. Some of the newer bait products
appear to have a lot of potential for control, but spreading
bait on greens mowed daily at 1/8” presents a problem….
Weeds
With the approaching cooler weather in September, it is time
to start spraying broadleaf weeds again for autumn control.
Some examples of persistent problem weeds include: clover,
black medic, knotweed, spurge, purslane and chickweed. Moss
and algae reports continue to roll in. We have had some good
moss control results in small test areas with a “tank mix”
of 4 oz / gal of Ultra Dawn and a tablespoon of baking soda
(predissolved in warm water before mixing). We are going to
further adjust rates of both the soap and soda in the mix
to see if some potential tip burn on foliage can be avoided.
