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A Famed Professor Retires, Overseeding And Warm-Season Grasses September 21, 2018 By Brian Whitlark, agronomist, West Region

Many courses experienced poor bermudagrass transition in 2018 – you must dig deeper to reveal how bermudagrass will recover next spring.

The iconic, brilliant, zany and charismatic Dr. David Kopec recently retired after running the University of Arizona’s turfgrass research and extension program for more than 32 years. Kopec's contributions to the turf industry in Arizona are plentiful. His work quantifying the annual turf consumptive use have changed the way golf courses use water. Kopec will likely be most remembered for his witty, charismatic presentations. There was never a dull moment during a Kopec presentation; no one left the room early and everyone got a good laugh while gleaning turf-maintenance information. As a tribute to Kopec, here are some of his best tips for overseeding and transition:


Overseeding strategies to avoid

Aggressive vertical mowing during overseeding –

Cutting stolons with aggressive vertical mowing when overseeding can eliminate 80-85 percent of stolon buds. Cut buds are lost growing points that bermudagrass can’t use to recover from overseeding come spring.

Early overseeding –

Ideally, overseeding should commence when soil temperatures at a 4-inch depth dip to 74-75 degrees Fahrenheit and overnight lows drop into the 50s. Overseeding when bermudagrass is still actively growing forces the turf to reallocate food reserves to regenerating leaves and stolons, which occurs at the expense of rhizomes and crowns. Interestingly, when looking back at weather data from the past two years, the ideal overseeding date in the Phoenix area was about the middle of October and the first week of November in 2016 and 2017, respectively. Unfortunately, most courses are forced to overseed too early so they can reopen for play when winter visitors return.


Bermudagrass trick or treat?

This year will be remembered as a relatively poor year for bermudagrass transition out of overseeding. Many courses experienced thin bermudagrass cover in June and through much of July. Fortunately, bermudagrass filled in by early September, but will the density and cover bring a trick or a treat during the next spring transition? Kopec always said that underground rhizomes are the only place from which bermudagrass will grow back during spring. Although fairways may have full cover now, don't be tricked into thinking bermudagrass has a robust rhizome system.


Save the date!

Warm-Season Grass Renovation Seminar – November 29, 2018 – San Jose Country Club in San Jose, California.

Save the date for a warm-season grass renovation seminar with host Golf Course Superintendent Pete Bachman at San Jose Country Club in San Jose, California, on Thursday, November 29. With pressing water issues in California, courses are looking to replace their cool-season turf swards with warm-season grasses such as bermudagrass or zoysiagrass. If you are interested in switching to warm-season grasses or upgrading from common bermudagrass to a new hybrid variety, spend a day in San Jose to hear speakers including Pat Gross, director of the USGA Green Section’s West Region; Dr. Marta Pudzianowska of the University of California Riverside; Golf Course Architect Andy Staples; Dr. Mike Kenna, director of USGA Green Section Research; and a panel of golf course superintendents talk about their experience with new warm-season turf varieties and renovation strategies. More information about this seminar will be included in the next update.

For more information on overseeding, transition and the upcoming warm-season grass renovation seminar, please contact the USGA Green Section.


West Region Agronomists:

Patrick J. Gross, regional director –

Larry W. Gilhuly, agronomist –

Brian S. Whitlark, agronomist –

Information on the USGA’s Course Consulting Service 

Contact the Green Section Staff

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