Turfgrass Scouting Report: 4/01/18
Many courses have now transitioned from using temporary flags in the approaches to opening up the putting greens for play. There will be many golfers braving the cold as Masters week is upon us. Unlike the growing conditions in Augusta, GA, the turf growing in the Midwest is still greening up at a very slow pace. Well behind last year’s pace.
A quick look at our growing degree day totals for 2017 and 2018. This graph reveals just how many fewer growing degree days that we have accumulated in 2018 compared to 2017. For those unfamiliar with growing degree days, these accumulated heat units are essentially a phenological indicator of plant maturity and are used in a number of plant systems.
The colder temperatures in March 2018 have also brought opportunities for late season snowfall. Sections of central Illinois received up to 10 inches of snowfall last week.
Fortunately the snowfall melted off quickly and folks were able to continue with spring preparations. In northern Illinois, much of our bentgrass surfaces are still very brown. Despite how brown the turf may appear, there is some green material that can shine when mowing is performed.
Mowing off the ‘excess’ material can reveal greener turf underneath. This effect is observed with mowing greens, fairways, or roughs. Not always, but in some cases the turf is rolled prior to mowing to even out any frost heaves.
Beyond creeping bentgrass, Kentucky bluegrass fairways and tees are also slowly coming to life during this cold month.
Last week, I had the opportunity to check out the ‘HGT’ Kentucky bluegrass fairways at Wilmette Golf Club. These fairways have outstanding recuperative potential through the spreading of below ground rhizomes as well has having a greater tolerance for dollar spot disease.
During this colder weather there are many folks who are covering selected areas of turf with tarps. Tarps can be helpful mitigating the effects of cold temperatures and frost as a means to hasten the growth or establishment of the turf.
However, the use of covers can lead to an enhanced risk of disease development. This week I observed yellow patch (caused by Rhizoctonia cerealis) that was developing on a newly established creeping bentgrass surface.
Fortunately yellow patch is a relatively minor disease and most of the injury is cosmetic. A closer inspection reveals that only the older leaf blades were damaged in this instance.
Occasionally this disease can mimic symptoms of pink snow mold, brown ring patch, or superficial fairy ring. Pink snow mold and brown ring patch will ‘fluff up’ when a sample is incubated or when the tarps are initially pulled off the turf. The lack of visible mycelium is a pretty good indication that Rhizoctonia cerealis is the culprit. What also helps rule out brown ring patch is host specificity. Brown ring patch is primarily a disease of annual bluegrass in the Chicagoland area.
While it has been cold in many areas of Illinois, it also has been burning hot in a few locations. This is the time of year that many facilities perform controlled burns to restore tall grass areas.
Two weeks after a control burn I was able to see regrowth of the desirable plants.
Temperatures look to stay seasonably cool in the foreseeable future. This will be a very drawn out transition period from winter to spring. Those closer to the lake will be further behind than those more inland.
Many folks are also beginning to wonder about preventative applications for crabgrass and root infecting diseases. Typically, we lean on 5-day average soil temperatures and phenological indicators to aid in our decision making.
As of March 30th, the 5-day average soil temperature at the 4-inch depth for northern Illinois (St. Charles and Freeport area) is 43 degrees F. In central Illinois (Springfield area) it is 46 degrees F and in southern Illinois (Carbondale area) it is 51 degrees F. Keep in mind that these are soil temperatures and may not reflect temperatures on putting green surfaces.
Those in southern Illinois are nearing the window to initiate preventative measures to combat crabgrass, take-all patch, fairy ring, and Pythium root diseases. Further to the north, we may still have another week or two before we start to pull the trigger on those applications.
On April 12th, Dr. Matt Elmore (Professor of turfgrass weed science at Rutgers) will be in town. Dr. Elmore’s research program focuses on many of the same problematic cool-season and warm-season weeds that plague us in Illinois.
Like any good friend, when he arrives I’m going to put him to work. Please reach out if you have any turfgrass weed control concerns and hopefully we will have time to stop by.