Golfdom, November 2018

Continued from page 29 Transition Zone Research done in 2017 recommended applying large patch fungicides when a seven day average of thatch temperatures cooled to 640 degrees F to 738 degrees F in fall Thatch temperature data were not recorded in our study but soil temperature averages at a 4 inch depth ranged from 698 degrees F to 732 degrees F for the seven days prior to application timing A at our locations We recommend tank mixtures of Proxy and fungicides for large patch control to reduce application labor and equipment costs However applicators should use a jar test to test for compatibility when adding other products to the mixture Further avoid applications before heavy rainfall is anticipated Rain reduces efficacy This research provides turf managers with insight on how to suppress Meyer zoysiagrass seedhead production Proxy applications were effective when applied in early fall about one month prior to winter dormancy and six months prior to peak zoysiagrass seedhead production These findings on Proxy application timing should apply to the majority of the Transition Zone However we need more research and practical experience to help refine recommendations for zoysiagrass seedhead suppression G Acknowledgements Thanks to Bayer Environmental Science for supporting this research Aaron Patton Ph D is a turfgrass scientist at Purdue University Jared Hoyle Ph D is a turfgrass scientist at Kansas State University Mike Harrell Ph D is a turfgrass scientist at the Southeastern Turfgrass Research Center and Zac Reicher Ph D is a turfgrass scientist with Bayer CropScience You may reach Aaron Patton at ajpatton@ purdue edu for more information References 1 Askew S D 2017 Plant growth regulators applied in winter improve annual bluegrass Poa annua seedhead suppression on golf greens Weed Technol 31 701 713 2 Brosnan J T G K Breeden M T Elmore A J Patton and D V Weisenberger 2012 Zoysiagrass seedhead suppression with imidazolinone herbicides Weed Technol 26 708 713 3 Forbes I 1952 Chromosome numbers and hybrids in Zoysia Agron J 44 194 199 doi 102134 agronj195200021962004 400040008x 4 Gelernter W D L J Stowell M E Johnson and C D Brown 2017 Documenting trends in land use characteristics and environmental stewardship programs on US golf courses Crop Forage Turfgrass Manage 3 1 1 12 doi 102134 cftm2016100066 5 Heide O M 1994 Control of flowering and reproduction in temperate grasses New Phytologist 128 347 362 6 Kreuser W C J R Young and M D Richardson 2017 Modeling performance of plant growth regulators Agric Environ Lett 2 170001 doi 102134 ael2017010001 7 Latting J 1972 Differentiation in the grass inflorescence In Youngner V B McKell C M eds The biology and utilization of grasses New York Academic Press pp 365 399 8 McCullough P E J Yu and S M Williams 2017 Seedhead development of three warm season turfgrasses as influenced by growing degree days photoperiod and maintenance regimens Internat Turfgrass Soc Res J 13 1 321 329 9 Obasa K J Fry D Bremer and M Kennelly 2017 Evaluation of spring and fall fungicide applications for large patch management in zoysiagrass Internat Turfgrass Soc Res J 13 191 197 10 Patton A J B M Schwartz and K E Kenworthy 2017 Zoysiagrass Zoysia spp history utilization and improvement in the United States A Review Crop Sci 57 S 37 S 72 doi 102135 cropsci2017020074 11 Sidhu S S J Yu and P E McCullough 2014 Physiological behavior of ethephon in five turfgrasses Crop Sci 54 1816 1822 12 Youngner V B 1961 Growth and flowering of Zoysia species in response to temperatures photoperiods and light intensities Crop Sci 1 91 93 doi 102135 cropsci19610011183X00010 0020003x 30 Golfdom November 2018 Golfdom com PHOTO BY MIKE HARRELL LOSE YOUR HEAD FIGURE 6 Green rectangles without seedheads and white colored shredded seed stalks on April 28 2017 illustrate successful seedhead inhibition from a Sept 29 2016 Proxy ethephon application in Lexington Ky