'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.

Low-Temperature Chamber for Winterkill Research

Dr. Kevin W. Frank and Dr. Emily Merewitz
Michigan State University

The low-temperature growth chamber that was purchased earlier this year by a partnership between the Michigan Turfgrass Foundation’s Founders Society, MSU AgBio Research, and the MSU Growth Chamber Facility has arrived at MSU.  The chamber will be used by MSU turf researchers to investigate winterkill of Poa annua putting greens.  Initial research projects have been funded by the USGA, MSU Project GREEEN and Syngenta and began earlier this summer at the Hancock Turfgrass Research Center.  Research is focusing on the effects of plant growth regulators and plant health treatments on turfgrass survival under ice.  Turfgrass cores from the field plots have been extracted and are in the process of being acclimated for ice treatment in the low-temperature chamber.  The objectives of these research projects are to determine treatments that can ultimately be used by golf course superintendents to minimize the risk of winterkill on putting greens. 

Thanks to the MTF Founders Society, MSU AgBio Research, and the MSU Growth Chamber Facility for purchasing the low-temperature chamber to facilitate our winterkill research efforts.

Graduate student Kevin Laskowski adjusting the temperature of the low-temperature chamber.

Preparing Turf for Winter

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

The winter of 2013-2014 shattered weather records and Poa annua putting greens.  Ice cover that endured from early January through mid-March was a significant factor in causing winterkill but there were certainly situations where crown hydration freeze injury or even desiccation injury on exposed sites also caused damage.  With winter on the horizon there is plenty of discussion on what to do now and what to do during winter to minimize the risk of winterkill.

Shade

Following last winter it was clear that any turf that was weak or simply not as healthy was exposed and killed.  In many instances the winterkill patterns mirrored shade patterns on greens.  Turfgrass growing in the shade is simply not as healthy as turfgrass growing in full sunlight.  To compound the problem trying to reestablish damaged greens in the shade resulted in longer recovery time than greens recovering in full sunlight.  Improving sunlight penetration to greens by removing and/or thinning tree canopies will improve turfgrass health and ultimately may improve the odds of turfgrass surviving winterkill events.   

In some instances winterkill mirrors shade patterns.

Covers

Covers are not widely used throughout Michigan, especially southeast Michigan.  There are probably several reasons including cost, storage, lifespan, and unpredictable winter weather.  Last winter was extreme with ice, snow, and cold temperatures.  The winter of 2012 if it’s remembered at all, is remembered for the mild temperatures that resulted in golf being played almost all winter long.  Keep in mind that all covers are not the same.  The permeable covers that were purchased by many golf courses this spring provided a tremendous advantage in reestablishment but will not provide absolute protection in the winter from thick ice cover.  Permeable covers will certainly provide some buffer/protection from low temperatures and desiccation and should be used if available but if this winter delivers another dose of lengthy ice cover, permeable covers can’t be counted on to prevent damage. 

Impermeable covers will protect the turf from ice cover damage but are not necessarily a panacea for all your winter worries.  Impermeable covers need to be ‘tucked down’ tightly to the surface to prevent any water from getting under the cover.  Impermeable covers will prevent gas exchange with the atmosphere so in that respect they actually mirror thick ice sheets.  Venting (exchanging air under the cover) impermeable covers throughout winter reduces the risk of anoxia developing under the cover.  To use or not use covers, especially impermeable covers can be a hotly debated topic.  Ultimately the golf course superintendent is the person that should make the decision.  After all no person knows the golf course, the environment, and the turf better.   

Covers can be used for winter protection and reestablishment.

Snow Mold & Covers

It is important to remember that greens covers act similar to snow cover when it comes to snow mold activity. The covers provide the same environmental conditions for the development of snow mold as the snow does. So if greens covers are placed on the greens in November and not removed until March, they will create the same environmental conditions for the development snow mold as golf courses in Northern Michigan experience where snow covers the turf for three or more months.  It is important that adequate levels of snow mold fungicides be applied to protect the turf for three or more months if covers will be used for this length of time. This usually means applying 3 way fungicide combinations at full label rates.  Microdochium patch will occur throughout the fall. It is most active when the temperatures are in the 60’s and combined with wet weather. Therefore, it is important to make fungicide applications throughout the fall to prevent Microdochium patch from developing.  If Microdochium patch is active at the time the covers are placed on the greens, it will continue to develop under the covers in spite of any fungicide applications. 

Winter Snow & Ice Removal: To Remove or not to Remove?

This question might make the cover debate seem tame.  Should you remove snow and ice and if so when should you start?  Last year was an anomaly with thick ice sheets that were in place for 90 days or greater in many areas.  Although some courses have been successful with removing snow throughout the winter this may not be feasible for some courses due to either lack of personnel or snow moving equipment.  Instead of being concerned with removing snow from the first event to the last, consider developing a removal strategy that targets ice duration and snowmelt that could lead to crown hydration freeze injury.  For example, if ice forms and is in place for greater than 30 days I would definitely make attempts to remove.  For crown hydration freeze injury consider removing snow in late February/early March prior to anticipated snowmelt.

Removing snow from a putting green.

Surface Drainage

The key to preventing or reducing the incidence of crown hydration freeze injury is good drainage.  For putting greens that lack adequate surface drainage, consideration may even be given to recontouring greens that are annual victims of crown hydration injury.  Less dramatic measures include cutting cup cutter sized holes in poorly draining areas and filling the cores with gravel or sand to try and move the water away from the surface.  Another more common tactic is to cut sod strips from greens to facilitate water movement off the greens once snowmelt begins.

Help the melt by stripping sod (photo courtesy Adam Garr)

Cultural Practices - Let it Grow!

Fall is prime time for cultural practices to improve turfgrass health.  In addition to core aeration and fall fertilization consideration should be given to raise mowing heights as fall progresses.  Higher mowing heights won’t save the turf alone if winterkill is again an issue, but it could certainly be a factor in producing a healthier plant and if you think back, how many putting greens had winterkill but the collar had no damage?  Granted, the greens aren’t going to look like collars going into winter but maybe even a slight increase in height might help.    

MSU December Turf School

Dr. Kevin W. Frank
Michigan State University

The MSU Turf School is an intensive four-day course designed to teach the basics of turfgrass science as well as the practical techniques of managing turfgrass.  The school will be "team taught" by MSU turfgrass faculty and staff.  The curriculum is designed to deliver a wide range of turfgrass management topics including basic soils and soil management, turfgrass species identification, selection and physiology, turf establishment and renovation, fertilization, proper pesticide use, and environmental stewardship.  A significant portion of the school is dedicated to weed, insect, and disease identification and management.  The pest management section is delivered in lecture and laboratory settings with hands-on learning emphasized.  The strength of the school lies within the depth of the turfgrass faculty at MSU. This will provide an excellent opportunity for one-on-one interaction between participants and the MSU turfgrass faculty. This is your chance to get to know the MSU Turf Team - all team members instruct, that includes.....Vargas, Rogers, Crum, Frank, Nikolai, Merewitz, Gilstrap, Smitley, Hathaway, Dykema, & Davis - if you know the name but not the face, this is your chance to meet and greet for an entire week!


Who Should Attend?

Anyone looking to add to their turf knowledge - the school starts with the turf basics and expands from there throughout the week. Past attendees include golf course employees without formal training, lawn care company employees, turfgrass mechanics, industry sales representatives, and school employees responsible for grounds and athletic fields.

What is Covered?

All things turf will be covered. Topics include: turfgrass species and cultivars including a hands-on identification lab, establishment and renovation, nutrition and fertilizers, weed, insect, and disease management including hands-on identification labs, 
turfgrass soils, cultivation, compaction, and thatch including a hands-on soils lab, and Poa annua management.

Where and When


This year's school will be held December 15-18, 2014 at the Hancock Turfgrass Research Center (4444 Farm Lane Rd.) on the campus of Michigan State University.  The school begins at 10:00 a.m. on Monday. It is recommended that lodging arrangements be made in the Lansing/East Lansing area to avoid long commutes each day. Local lodging information will be forwarded upon request.

Credits!
Need some MDA credits or GCSAA CEU points? Turf school is the place to clean up. At past Turf School’s we were awarded 20 MDA pesticide recertification credits available in categories Commercial Core, Private Core, 3A, and 6. In the past, turf school was also awarded 3.15 education points from GCSAA.

How Much?
Cost for the school is $600.00 and includes all class materials and lunches each day. Please register by Dec. 1 to ensure your spot.
 

Contact Kevin Frank at 517-355-0271 x 1147 or frankk@msu.edu for any questions.