Warmer-than-normal spring temperatures in the desert Southwest have expedited bermudagrass growth. Bermudagrass will begin new stem and leaf growth where ryegrass was overseeded, but these new shoots may eventually die if shaded by the ryegrass canopy. As such, it is critical this time of year to lower mowing heights in overseeded rough areas and fairways and to conduct light-intensity vertical mowing practices to improve sunlight exposure to the underlying bermudagrass.
Two additional strategies that are gaining widespread popularity throughout the Southwest region are brushing and chemical growth regulation. Either gear-driven or out-front brushes can be outfitted on walking and riding greens mowers, approach mowers and even fairway units. Brushing can be employed as frequently as five to seven days per week on putting greens and can be utilized during each mowing event on approaches and fairways. Brushing will increase clipping yield and slowly thin the cool-season grass canopy. Brushing reduces the density of the overseeded Poa trivialis and/or ryegrass which encourages the ability of the underlying bermudagrass to recover. Further information on brushing can be found by clicking on the following links: The Art of Brushing; Bring Back Brushing; Fine Tuning for Fine Turf.
Chemical growth regulation with mefluidide (Embark®) has only recently gained popularity as a transition aid. The Embark ® 2-S formulation can be used on ryegrass fairways, tees, roughs and approaches. Golf course superintendents have found that 6 to 7 ounces of product per acre will reduce ryegrass growth and its competitive advantage over the bermudagrass. The spray protocol calls for three sequential applications spaced approximately four weeks apart, typically beginning in March. Recently, a superintendent who is using this strategy noted that the price of spraying mefluidide easily paid for itself in the form of labor and fuel savings that would have been spent mowing during the most aggressive ryegrass growing months. It was interesting to find that the use of mefluidide in this capacity was researched at Clemson University in the late 1980s, and the article Overseeding in Transition was published in Golf Course Management that mentioned this strategy: Mazur, A. R. 1993. Golf Course Management. September. 61(9): p. 20, 22, 24, 26, 30.
Don’t wait for Mother Nature to induce bermudagrass transition when you can employ nondisruptive, frequent strategies to decrease the competitive advantage of ryegrass and encourage the growth of underlying bermudagrass.
Source: Brian Whitlark (bwhitlark@usga.org)
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