Winterkill Update Spring 2015

Dr. Kevin W. Frank and Dr. Joe Vargas, Jr.
Michigan State University

The winter of 2013-2014 produced devastating levels of winterkill, especially in the Detroit area.  As a result of the damage experienced to Poa annua putting greens last year golf course superintendents devised plans for this winter to reduce the potential for winterkill including using different cover systems and in some instances actively removing snow events to prevent any possibility of ice forming on putting greens.  Despite all of these efforts it appears that once again this spring Poa annua putting greens have been damaged.  Although the damage I’ve observed this year doesn’t appear at this time to be as severe as in 2014, the geographic extent of the damage in Michigan appears larger.  Initial observations and reports from the field indicate damage extending from at least the Grand Rapids region through greater Detroit.  Damage once again may be attributed to ice sheets on putting greens.  Many golf courses report ice sheets that formed around January 1 and in some cases didn’t melt off until early March, approximately 60 days of ice cover.  The day estimates for Poa annua survival under ice range from 45 to 90 days and for creeping bentgrass from 90 to 120 days.  For the Poa annua greens the ice cover from this winter was definitely in the range when damage can occur.  There also may be damage due to low temperature kill and/or desiccation for greens that were exposed throughout winter.  Crown hydration freeze injury also appears to be evident on some greens especially in poorly draining areas, although this injury could also be from thicker ice sheets that formed early in winter in these depressions.  

Possible winterkill following surface drainage pattern.

Poa annua loses its cold temperature hardy proteins and begins to take up water quickly as temperatures warm in the spring.  As snow melts and water collects in low lying or poorly draining areas if the temperature drops below freezing and ice forms it can crush the swollen crowns of Poa annua plants killing them.  To date, determining the extent of damage has been difficult as temperatures have been very cold and very little turf growth has occurred.  Since the snow melted it has been a very dry spring, to facilitate recovery it would be a good idea to charge up the irrigation system so when the warmer weather arrives plants emerging from dormancy will have access to water.  If the weather forecast is correct, and warmer temperatures arrive next week assessing the extent of damage will be easier. 

Steve Glossinger Receives Honorary Certificate

Steven Glossinger, CGCS, was the recipient of the Michigan State University Institute of Agriculture Technology's honorary certificate at the IAT graduation ceremony on March 22, 2015.  Mr. Glossinger began his Superintendent career in Michigan at Signal Point Club in Niles in 1977.  He was also Superintendent at Battle Creek CC, Point O'Woods G & CC, and Oakland Hills CC in Michigan.  He has been the superintendent at Caves Valley Golf Club in Owings Mills, MD since 1997.  He has provided guidance to MSU interns annually since 1988, many of whom are now at prominent clubs across the country.  He devotion to the turf program in terms of time and effort to train these young men and women cannot be overstated.  Congratulations Steve!

Steve Glossinger

'Flagstick' Dollar Spot Resistant Creeping Bentgrass

Dr. J. M. Vargas Jr., Ron Detweiler, and Nancy Dykema

Michigan State University

About 20 years ago, my laboratory personnel discovered some creeping bentgrass plants at the Hancock Turfgrass Research Center that appeared to be resistant to dollar spot, caused by Sclerotinia homoeocarpa. Thanks to funding from The Michigan Turfgrass Foundation and Project GREEEN, we were able to do some breeding with the dollar spot resistant plants. Small plots were established with these resistant lines and, throughout the years, they have remained resistant to dollar spot. Around 12 years ago we partnered with Seed Research of Oregon, a subsidiary of Pickseed USA. They continued the process of developing a dollar spot resistant creeping bentgrass cultivar. The cultivar, coded as SRP-1WM, was entered into the National Turfgrass Evaluation Program (NTEP) trials and tested at many universities through the United States where it remained resistant to dollar spot. The cultivar, now called Flagstick, is now available in limited supplies for 2015. There will be more available for the 2016 season. The importance of the first truly dollar spot resistant commercial turfgrass is enormous.  Most of the fungicide applications throughout the season in the Northeast and Midwest are for control of dollar spot.  Last year in Michigan, if it was not for dollar spot, very few fungicide applications would have been applied to golf courses. Having a dollar spot resistant cultivar on golf course greens, tees and especially fairways, which encompass acres of turf, will result in financial savings to golf courses as well as reduced environmental impact from fewer fungicide applications.

Creeping bentgrass cultivars in a fairway trial at MSU.

Ice on Putting Greens

Dr. Kevin W. Frank
Michigan State University

Once again this winter there are many golf course superintendents throughout the northern United States and across Canada that are coping with ice cover on putting greens.  At least in Michigan, it is nothing like what we experienced last winter where it was common to find ice sheets several inches thick.  This year it appears that in most cases if ice is present it is rather thin except in pocketed areas on greens where it may be thicker.  Also different from last year is when the ice formed.  At the Hancock Turfgrass Research Center (HTRC) on campus snowmelt that occurred on Jan. 17-18 when daytime temperatures reached 45 °F resulted in thin (less than 1 inch) ice sheets forming on greens.  This ice formation was approximately 3 weeks later than when ice formed in 2014.  On March 2, 2014 greens were already under ice cover for 63 days.  Today, March 2, 2015 greens at the HTRC have been under ice cover for 43 days.  Last year based on sampling turf plugs from beneath the ice sheet, Poa annua at HTRC appeared to survive until approximately 60 days under ice.  Samples collected from 60 days started to display damage.  Estimates of days of ice cover causing death vary from 45-90 for Poa annua and 120 days for creeping bentgrass.  Currently we are approaching the low day threshold for Poa annua, it doesn’t appear we’ll come close to the day threshold for creeping bentgrass unless this winter endures through April.

Poa annua samples from 58 days under ice in 2014, 8 days of growth.

I’m also not as concerned with the thin ice sheets as I believe there is a greater chance for porosity/gas exchange with the atmosphere that minimizes anoxia injury as opposed to the thick ice sheets we experienced last year.     

Thin ice sheets are less susceptible to anoxia injury.

What can or should I do now?

Whether or not to attempt ice removal is a difficult decision for golf course superintendents.  The decision to remove ice can be based on several factors including: turf sampling/past history, duration of ice cover, current and future temperatures, ability to remove water following melting from the green, and labor.

1. Sampling – sample greens under ice to assess survival.  There is variability in sampling and just because your sample comes out alive doesn’t mean all areas on the green will survive – same can be said if your sample is dead.  Also, consider any sampling results from previous years.  Did your Poa survive 30, 45, or 60 days?    

2. Duration of ice cover – how many days have your greens been covered in ice?  If you’re approaching or have already crossed the 45 day threshold I’d suggest making plans for removing ice.    

3. Temperatures – although our local Michigan forecast looks messy the next 24-48 hrs. with snow/rain/icing being forecast when you extend out to next weekend the temperatures appear to be favorable for melting.  Part of the concern with removing ice is exposing the turf to cold air temperatures.  Removing ice can be a difficult decision but in some ways you’re in a no win situation.  Leave the ice in place and damage can occur, remove the ice and expose the turf to low temperatures and damage is also possible.  Personally, I’d hedge towards removing the ice and/or helping the melt as temperatures moderate. 

Extended forecast for East Lansing, MI

4. Melting ice – there are many different products that have been used to melt ice including black sand, dark colored natural organic fertilizers, sunflower seeds, and fertilizers.  The key to any melting strategy is to be able to remove the water from the green following melting so it doesn’t refreeze and form another ice sheet.  If you can remove the snow above the ice prior to the moderating temperatures in the forecast it’s entirely possible thin ice sheets may melt on their own.  Of course I am relying on a 5-10 day forecast, insert your own weather forecast joke here.   

5. Labor – if you’re going to remove ice you need help.  Ice removal is not a 1-person job. If your golf course has 18 greens covered in ice even with several employees helping this is not going to be finished in 1 day. 

No Guarantees

Unfortunately there are no guarantees with respect to winterkill and whether or not ice is removed.  The days under ice cover for survival are estimates from research and conditions from course to course and even within the same course vary thereby effecting how long turf can survive under ice.