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Physiological Basis for Tall Fescue (Festuca arundinacea) Tolerance to Florasulam

  • Jialin Yu (a1), Patrick E. McCullough (a2) and Mark A. Czarnota (a3)


Tall fescue is susceptible to injury from many acetolactate synthase (ALS) inhibitors used for broadleaf weed control in turfgrass. Florasulam is an ALS inhibitor that selectively controls broadleaf weeds in tall fescue, but the mechanisms for selectivity are not well understood. The objective of this research was to evaluate the physiological basis of tall fescue tolerance to florasulam. In greenhouse experiments, florasulam rates required to injure tall fescue 20% (I20) and white clover 80% (I80) measured 320 and 65 g ai ha–1, respectively. The I20 and I80 values of another ALS inhibitor, flucarbazone, on these species measured 33 and 275 g ai ha–1, respectively. In laboratory experiments, the time required to reach 50% foliar uptake for 14C-florasulam and 14C-flucarbazone measured 23 and 62 h for white clover, respectively, and >72 h for both herbicides in tall fescue. The half-lives of florasulam and flucarbazone in tall fescue were 15 and 40 h, respectively, whereas the half-life in white clover was >72 h for both herbicides. The concentrations of florasulam and flucarbazone required to inhibit ALS enzymes 50% in excised leaves of tall fescue measured >1,000 and 32 μM, respectively. The selectivity of florasulam for white clover control in tall fescue is associated with differential levels of absorption and metabolism between species. Tall fescue has faster metabolism and less ALS enzyme inhibition from florasulam as compared to a more injurious ALS inhibitor, flucarbazone, which contributes to the differential tolerance levels between these herbicides.


Corresponding author

Author for correspondence: Patrick E. McCullough, Department of Crop and Soil Sciences, University of Georgia, 1109 Experiment Street, Griffin, GA 30233. (Email:


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Anonymous (2006) RevolverTM Herbicide Label. Bayer CropScience LP. Research Triangle Park, NC: Bayer CropScience LP
Anonymous (2009) Sapphire® Herbicide Label. Dow AgroSciences LLC. Indianapolis, IN: Dow AgroSciences LLC
Anonymous (2011) Plateau® Herbicide Label. BASF Corp. Research Triangle Park, NC: BASF Corp
Anonymous (2012) Quali-Pro® Herbicide Label. Makhteshim Agan of North America, Inc. Raleigh, NC: Makhteshim Agan of North America, Inc
Anonymous (2013) SedgeHammer® Herbicide Label. Gowan Co. Yuma, AZ: Gowan Co
Anonymous (2014a) DefendorTM Dow AgroSciences LLC Herbicide Label. Indianapolis, IN: Dow AgroSciences LLC
Anonymous (2014b) Everest® Herbicide Label. Arysta Lifescience North America, LLC. Cary, NC: Arysta Lifescience North America, LLC
Anonymous (2015) Katana® Herbicide Label. PBI/Gordon Corp. Kansas City, MO: PBI/Gordon Corp
Baghestani, MA, Zand, E, Soufizadeh, S, Bagherani, N, Deihimfard, R (2007) Weed control and wheat (Triticum aestivum L.) yield under application of 2,4-D plus carfentrazone-ethyl and florasulam plus flumetsulam: evaluation of the efficacy. Crop Protection 26:17591764
Beam, JB, Barker, WL, Askew, SD (2006) Selective creeping bentgrass (Agrostis stolonifera) control in cool-season turfgrass. Weed Technol 20:340344
Bhowmik, PC, Bingham, SW (1990) Preemergence activity of dinitroaniline herbicides used for weed control in cool-season turfgrasses. Weed Technol 4:387393
Brosnan, JT, Breeden, GK, Vargas, JJ, Grier, L (2015) A biotype of annual bluegrass (Poa annua) in Tennessee is resistant to inhibitors of ALS and photosystem II. Weed Sci 63:321328
Chachalis, D, Reddy, KN, Elmore, CD, Steele, ML (2001) Herbicide efficacy, leaf structure, and spray droplet contact angle among Ipomoea species and smallflower morningglory. Weed Sci 49:628634
Christopher, JT, Powles, SB, Holtum, JA (1992) Resistance to acetolactate synthase-inhibiting herbicides in annual ryegrass (Lolium rigidum) involves at least two mechanisms. Plant Physiol 100:19091913
Cobb, AH, Reade, JPH (2011) Herbicides and plant physiology. 2nd edn. Ames, Iowa: Wiley-Blackwell. Pp 78–81
Cotterman, JC, Saari, LL (1992) Rapid metabolic inactivation is the basis for cross-resistance to chlorsulfuron in diclofop-methyl-resistant rigid ryegrass (Lolium rigidum) biotype SR4/84. Pest Biochem Physiol 43:182192
Cross, RB, McCarty, LB, Tharayil, N, Whitwell, T, Bridges, WC Jr (2013) Detecting annual bluegrass (Poa annua) resistance to ALS-inhibiting herbicides using a rapid diagnostic assay. Weed Sci 61:384389
DeBoer, GJ, Thornburgh, S, Ehr, RJ (2006) Uptake, translocation and metabolism of the herbicide florasulam in wheat and broadleaf weeds. Pest Manag Sci 62:316324
Derr, JF (2012) Broadleaf weed control with sulfonylurea herbicides in cool-season turfgrass. Weed Technol 26:582586
Gallaher, K, Mueller, TC, Hayes, RM, Schwartz, O, Barrett, M (1999) Absorption, translocation, and metabolism of primisulfuron and nicosulfuron in broadleaf signalgrass (Brachiaria platyphylla) and corn. Weed Sci 47:812
Harrell, MS, Williams, DW, Brecke, BJ (2005) Evaluation of sulfonylurea herbicides on cool and warm season turf species. Applied Turfgrass Sci, 2. doi: 10.1094/ATS-2005-1121-01-RS
Hixson, AC, Gannon, TW, Yelverton, FH (2009) Efficacy of application placement equipment for tall fescue (Lolium arundinaceum) growth and seedhead suppression. Weed Technol 21:801806
Johnson, BJ (1997) Sequential applications of preemergence and postemergence herbicides for large crabgrass (Digitaria sanguinalis) control in tall fescue (Festuca arundinacea) turf. Weed Technol 11:693697
Kalnay, PA, Glenn, S (2000) Translocation of nicosulfuron and dicamba in hemp dogbane (Apocynum cannabinum) 1. Weed Technol 14:476479
Loughner, DL, Alexander, AL, Ogawa, T, Breuninger, JM, inventor; Dow Chemical Company, assignee (2013) Penoxsulam as a turfgrass, vineyard and orchard floor herbicide. US patent 8557739:B2
Lycan, DW, Hart, SE (2004) Relative tolerance of four cool-season turfgrass species to sulfosulfuron. Weed Technol 18:977981
McCullough, PE, Sidhu, SS, Singh, R, Reed, TV (2014) Flucarbazone-sodium absorption, translocation, and metabolism in bermudagrass, Kentucky bluegrass, and perennial ryegrass. Weed Sci 62:230236
McCullough, PE, Yu, J, Brosnan, JT, Breeden, GK (2012) Relative tolerance of perennial ryegrass (Lolium perenne) and tall fescue (Festuca arundinacea) to flucarbazone. Weed Technol 26:673678
McElroy, JS, Breeden, GK (2007) Tolerance of turf-type tall fescue established from seed to postemergence applications of mesotrione and quinclorac. HortSci 42:382385
Nishimoto, RK, Murdoch, CL, McCarty, LB, Weinbrecht, JS (1997) Purple nutsedge control by halosulfuron or imazaquin/MSMA in turfgrass in the tropics. J Turfgrass Manag 2:2333
Powles, SB, Yu, Q (2010) Evolution in action: plants resistant to herbicides. Ann Rev Plant Biol 61:317347
Reed, TV, McCullough, PE (2012) Application timing of aminocyclopyrachlor, fluroxypyr, and triclopyr influences swinecress control in tall fescue. HortSci 47:15481549
Sanyal, D, Bhowmik, PC, Reddy, KN (2006) Influence of leaf surface micromorphology, wax content, and surfactant on primisulfuron droplet spread on barnyardgrass (Echinochloa crus-galli) and green foxtail (Setaria viridis). Weed Sci 54:627633
Wanamarta, G, Penner, D (1989) Foliar absorption of herbicides. Rev Weed Sci 4:215231
Westerfield, W (1945) A colorimetric determination of blood acetoin. J Biol Chem 161:495502
Yu, Q, Powles, SB (2014) Resistance to AHAS inhibitor: current understanding. Pest Man Sci 70:13401350


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Physiological Basis for Tall Fescue (Festuca arundinacea) Tolerance to Florasulam

  • Jialin Yu (a1), Patrick E. McCullough (a2) and Mark A. Czarnota (a3)


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