Golf Course Management

JAN 2017

Golf Course Management magazine is dedicated to advancing the golf course superintendent profession and helping GCSAA members achieve career success.

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120 GOLF COURSE MANAGEMENT 01.17 Professor Bernard Zandstra has been re- searching vegetable production for nearly 50 years. Several weeks ago, I watched him lecture about weed encroachment in veg - etable row crops. Problems include a lack of crop density resulting in exposed soil, which creates a perfect environment for weed seed germination. Also, many weeds in vegetable fields come from the same family as the cash crop. These two problems mean hand-weed - ing is often required to avoid herbicide injury to the cash crop. As he lectured, I recalled some Americans I had met in a Scottish pub last September. They were on a golf vacation, and when they learned I was in Scotland giving a putting green management seminar, one of them grumbled, "I wish you would come to our golf course and do something about the Poa. Our superintendent doesn't have a clue what to do." Now before I proceed with this story, let's step outside and have a smoke. Twenty-seven years before that exchange in the pub, I began doing research with Bruce Branham, Ph.D. We were experimenting with some new chemistries now known as PGRs. At that time, the best ways to remove annual bluegrass from bentgrass — or any other grass stand — was to pull it or spray it with a nonselective herbicide and hope for decent control. Like many of the weeds in the vegetable field, all the grassy weeds in our preferred stand of turf come from the same family. How to eradicate one member of a plant fam - ily without killing, stunting or at least dis- coloring another member of the same fam- ily should be understood as problematic and ought to be hailed as a miracle of chemistry if obtained. However, just because many of these chemistries exist does not mean the re - sults translate from one site to another. Now, back to the American golfers. Unbe - lievable as it may seem, the golfer who grum- bled about the Poa was a member at Lost Dunes Golf Club in Michigan, where I had spent the previous year attempting to eradi - cate the Poa from a bentgrass green by using PoaCure (methiozolin). Either I or my techni - cian, Aaron Hathaway, had personally made the herbicide applications. During the same period, Aaron had been performing identical studies at the Hancock Turfgrass Research Center (HTRC) and at Forest Akers Golf Course, about a half-mile from the HTRC. The results: nearly 100% eradication of Poa at Forest Akers, 60% at HTRC, and nothing noticeable at Lost Dunes. The discrepancy in results is huge, espe - cially when you consider that the same people were making identical applications with the same spray equipment. Why does this hap - pen? Why can't we get the same results when trying to remove one grass from a stand of another grass? No one is certain, but some good theories include: different biotypes of Poa; different soil types; antagonism with chemicals that are being applied at one site and not another (most likely a PGR); the pH of the water; or other environmental differ - ences. When less-than-perfect outcomes are obtained, researchers often play with timing intervals and rates. This past December, I heard Douglas McCullen of Bayer discuss inconsistencies of seedhead suppression with Proxy (ethephon). For the past two years, Bayer has been per - forming university research at several sites, including HTRC, by making late-fall/early- winter applications of Proxy. Douglas showed data from multiple sites and asked, "Can we say we get 100% seedhead suppression with late-fall applications of Proxy? The answer is no, because there are differences from site to site that we can't explain. However, we can say we get 70% to 90% improved seedhead suppression with the late-fall applications." I want readers to remember that, when it comes to removing a grass from a grass, we are fortunate to have the chemistries we have. Unfortunately, the results are not identical from site to site, and we aren't sure why. We will continue to identify reasons for the in - consistencies for at least the next four years. Why the next four years? Well, heck, the president-elect of the United States owns golf courses, so I don't foresee anything that would prevent turfgrass research for at least that long. In any event, let's be happy we don't have to pull weeds like our friends in vegeta - ble production. Thomas A. Nikolai, Ph.D., the "Doctor of Green Speed," is the turfgrass academic specialist at Michigan State University in East Lansing, Mich., and a frequent GCSAA educator. Thomas A. Nikolai, Ph.D. nikolait@msu.edu All in the family Why does this happen? Why can't we get the same results when trying to remove one grass from a stand of another grass? (up to speed)

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