Tall fescue and common bermudagrass are common turf types in the transitional zone of the United States. With these two types of turfgrass species cultivated in the same area there is concern for contamination and a non-uniform turfgrass stand. Common bermudagrass is particularly invasive in cool-season turf like tall fescue because of its vigorous growth rate and rhizomatous-stoloniferous habit.
Mowing height can influence bermudagrass encroachment into tall fescue
Tall fescue and common bermudagrass are common turf types in the transitional zone of the United States. With these two types of turfgrass species cultivated in the same area there is concern for contamination and a non-uniform turfgrass stand. Common bermudagrass is particularly invasive in cool-season turf like tall fescue because of its vigorous growth rate and rhizomatous-stoloniferous habit. Like typical weed infestations the two turfgrasses are non-uniform in appearance and aesthetically unpleasing. The bi-species turfgrass stand causes problems when trying to manage for weeds because most common herbicides have selective tolerance to the either tall fescue or common bermudagrass but not both. It can cause safety problems when turf is in a high traffic area. In golf course roughs, it can cause ball playability issues. The mixture of turf species does not allow for golfers to anticipate club reaction when striking at a ball in two different species of turfgrass. Most importantly the color discrepancy causes unsightly views in the winter months in the transitional zone.
There are selective and non-selective herbicidal control options to remove common bermudagrass in tall fescue. Glyphosate has typically been utilized as a spot treatment to control bermudagrass. The consequence to this type of control is that it produces unsightly necrotic areas in the turfgrass system. Selective herbicidal control options include fenoxaprop and ethofumsate (0.2 + 1.7 kg ha-1) combination treatments that can be used to control common bermudagrass in tall fescue within one year (Johnson and Carrow 1995). Other applications include monthly applications of fenoxaprop plus triclopyr from June through September. Fluzaifop can be applied in the spring and fall for bermudagrass suppression (Yelverton et al. 2008). Some of these options are pricey and require multiple applications of multiple products during the year. Also, application by a licensed pesticide applicator is required for some products. These applications are expensive because of tank mixing and multiple applications.
Other research has shown cultural factors for minimizing invasion of common bermudagrass into tall fescue. The cultural factors specifically evaluated included mowing height, seeding rate of tall fescue ‘Mustang’ and ‘Kentucky 31’, and source of bermudagrass ‘Guymon’ introduction (seed, rhizomes, clippings). Results showed that there was no bermudagrass invading tall fescue at the higher mowing height (2.25 inches) compared to the lower mowing height (0.75 inches). Brede (1992) concluded that common cultural practices influenced the amount of bermudagrass invasion in tall fescue.
Therefore, options exist which turfgrass managers can implement through regular maintenance of their lawn to allow for suppression of common bermudagrass in a contaminated tall fescue stand.
Always remember to READ THE LABEL for the correct rate, turfgrass tolerance, and specific instructions before application!!!-By Jared Hoyle, KSU Turfgrass Extension Specialist
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Brede, A.D. 1992. Cultural factors for minimizing bermudagrass invasion into tall fescue turf. Agron. J. 84:919-922.
Hoyle, J.A. 2009. Effect of Mowing Height in turfgrass systems on Pest Incidence. Master’s thesis. Raleigh, NC: North Carolina State University. 77p.
Johnson, B.J and R.N. Carrow. 1995. Influence of Fenoxaprop and Ethofumesate on suppression of common bermudagrass (Cynodon dactylon) in tall fescue (Festuca arundinacea) turf. Weed Tech. 9:789-793.
Wilkinson, S.R., L.F. Welch, G.A. Hillsman, and W.A. Jackson. 1968. Compatibility of tall fescue as affected by nitrogen fertilizer and height of clip. Agron. J. 60:359-362.
Yelverton, F. H., B. R. Lassiter, G. G. Wilkerson, L. Warren, T. W. Gannon, J. J. Reynolds, and B. S. Boul. “Bermudagrass (Cynodon dactylon L. Pers.).” Turffiles. 15 July 2008. North Carolina State University. 24 Mar. 2009 <http://www.turffiles.ncsu.edu/Weeds/Bermudagrass.aspx>.