safety in Christmas tree production and weed control effectiveness. Westar 75 DG (DuPont Corp., Wilmington, DE) is a combination of 68.6% hexazinone, a photosynthesis inhibitor, and 6.5% sulfometuron-methyl, an acetolactate synthase inhibitor ( DuPont
Linglong Wei, Jarrod J. Morrice, Rodney V. Tocco, and Bernard H. Zandstra
J.M. Goatley Jr., A.J. Powell Jr., W.W. Witt, and M. Barrett
Chlorsulfuron, diclofop, and sulfometuron were evaluated for potential use in selective control of tall fescue (Festuca arundinacea Schreb.) in Kentucky bluegrass (Poa pratensis L.). Polynomial trend analyses indicated highly significant linear and quadratic response curves for percentage of tall fescue reduction for each herbicide. Fall and spring treatments with chlorsulfuron and diclofop provided significant tall fescue control, with slight to moderate initial Kentucky bluegrass phytotoxicity. Fall and spring applications of sulfometuron resulted in excellent tall fescue control, but initial Kentucky bluegrass damage was severe and would be unacceptable for high maintenance turf. Chemical names used: 2-chloro- N -[[(4-methoxy-6-methyl-l,3,5-triazin-2-yl)amino]carbonyl]-benzenesulfonamide (chlorsulfuron); 2-[4-(2,4-dichlorophenoxy)phenoxy]proponoate (diclofop); N -[[(4,6-dimethylpyrimidin-2-yl)amino]carbonyl]-2-methoxycarbonyl-benzenesulfonamide (sulfometuron).
Edward W. Bush, Wayne C. Porter, Dennis P. Shepard, and James N. McCrimmon
Field studies were performed on established carpetgrass (Axonopus affinis Chase) in 1994 and 1995 to evaluate plant growth regulators (PGRs) and application rates. Trinexapac-ethyl (0.48 kg·ha-1) improved turf quality and reduced cumulative vegetative growth (CVG) of unmowed and mowed plots by 38% and 46%, respectively, in 1995, and suppressed seedhead height in unmowed turf by >31% 6 weeks after treatment (WAT) both years. Mefluidide (0.14 and 0.28 kg·ha-1) had little effect on carpetgrass. Sulfometuron resulted in unacceptable phytotoxicity (>20%) 2 WAT in 1994 and 18% phytotoxicity in 1995. In 1995, sulfometuron reduced mowed carpetgrass CVG 21%, seedhead number 47%, seedhead height 36%, clipping yield 24%, and reduced the number of mowings required. It also improved unmowed carpetgrass quality at 6 WAT. Sethoxydim (0.11 kg·ha-1) suppressed seedhead formation by 60% and seedhead height by 20%, and caused moderate phytotoxicity (13%) in 1995. Sethoxydim (0.22 kg·ha-1) was unacceptably phytotoxic (38%) in 1994, but only slightly phytotoxic (7%) in 1995, reduced clipping yields (>24%), and increased quality of mowed carpetgrass both years. Fluazasulfuron (0.027 and 0.054 kg·ha-1) phytotoxicity ratings were unacceptable at 2 WAT in 1994, but not in 1995. Fluazasulfuron (0.054 kg·ha-1) reduced seedhead height by 23% to 26% in both years. Early seedhead formation was suppressed >70% when applied 2 WAT in 1994, and 43% when applied 6 WAT in 1995. The effects of the chemicals varied with mowing treatment and evaluation year. Chemical names used: 4-(cyclopropyl-x-hydroxy-methylene)-3,5 dioxo-cyclohexane-carboxylic acid ethyl ester (trinexapac-ethyl); N-2,4-dimethyl-5-[[(trifluoro-methyl)sulfonyl]amino]phenyl]acetamide] (mefluidide); [methyl 2-[[[[(4,6-dimethyl-2-pyrimidinyl) amino]carbonyl] amino] sulfonyl]benzoate)] (sulfometuron); (2-[1-(ethoxyimino)butyl-5-[(2-ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one) (sethoxydim); 1-(4,6-dimethoxypyrimidin-2yl)-3-[(3-trifluoromethyl-pyridin 2-yl) sulphonyl] urea (fluazasulfuron).
Jack D. Fry and D. Wayne Wells
Field studies were conducted in south Louisiana to identify plant growth regulators that suppress carpetgrass (Axonopus affinis Chase.) seedhead development. In an initial study, best results were obtained with sethoxydim (0.11 kg·ha-1) and sulfometuron methyl (0.6 kg·ha-1), which reduced seedhead development by 88% and 86%, respectively, compared to untreated plots 21 days after treatment. Sulfometuron methyl caused unacceptable carpetgrass injury, however. Evaluation of seven sethoxydim application levels between 0 and 0.34 kg a.i./ha showed that carpetgrass seedhead number and elongation rate declined with increasing sethoxydim amount [SEEDHEAD NUMBER (m-2) = 515 – 1340 (kg), R 2 = 0.82; ELONGATION (cm) = 25.3 – 151 (kg) + 276 (kg2), R 2 = 0.77]. Carpetgrass seedhead production was restricted up to 6 weeks after sethoxydim (0.17 and 0.22 kg·ha-1) application. Chemical names used: (2-[1-(ethoxyimino)butyl]-5-[2-ethylthio)propyl)-3-hydroxy-2-cyclohexen-1-one) (seth-oxydim); (2-[[[[(4,6-dimethyl-2-pyrimidinyl)amino]carbonyl]amino]sulfonyl]benzoic acid) (sulfometuron methyl).
Jack D. Fry
A field study was conducted in southern Louisiana to screen several plant growth regulators (PGRs) for efficacy in suppressing centipedegrass [Eremochloa ophiuroides (Munro) Hack.] vegetative growth and seedhead production. PGRs were applied in three sequential treatments in 1988 and included ethephon, glyphosate, mefluidide, paclobutrazol, sethoxydim, and sulfometuron methyl. Ethephon (5.0 kg·ha-1) suppressed mean centipedegrass vegetative growth by 15% with no turf injury. Mefluidide (0.6 kg·ha-1) and ethephon reduced mean seedhead number by 55% and 61%, respectively. Glyphosate (0.6 kg·ha-1) suppressed vegetative and reproductive growth, but caused unacceptable phytotoxicity and reduced centipedegrass cover and quality during Spring 1989. Use of ethephon or mefluidide to reduce trimming requirements or mower operation in hazardous areas may be an effective means of inhibiting centipedegrass growth. Chemical names used: N -(phosphonomethyl) glycine (glyphosate); N -[2,4-dimethyl-5-[[(trifluromethyl) sulfonyl]amino] phenyl]acetimide (mefluidide); 2-[1-(ethoxyimino)butyl] -5[2-(ethylthio) propyl]-3-hydroxy-2-cycIohexen-l-one (sethoxy-dim); 2-[[[[(4,6-dimethyl-2 -pyrimidinyl) amino] carbonyl]amino] sulfonyl]benzoic acid (sulfometuron methyl); (2-chloroethyl) phosphoric acid (ethephon); (±)-(R*R*)β-[(4-chlorophenyl)methyl]-α-(l,l-dimethylethyl) -1 H -l,2,4-triazole-l-ethanol (paclobutrazol).
D.L. Turner, S.S. Sharpe, and Ray Dickens
“Effects of selected herbicides on sod tensile strength and rooting of mature and immature turf of common centipedegrass [Eremochloa ophiuroides (Munro.) Hack] were studied in field experiments. Herbicides evaluated were atrazine, atrazine + tridiphane, bensulide, DCPA, DPX-6316, imazapyr, imazaquin, napropamide, oxadiazon, pendimethalin, sethoxydim, simazine, and sulfometuron. At 2, 4, and 8 weeks after treatment (WAT), sod tensile strength was determined, and root length and number were measured 7 to 10 days later. In 1986 sod tensile strength was not affected, but in 1987 the tensile strength of the immature turf was reduced at 8 WAT by bensulide and imazapyr. Rooting was suppressed most by benstdide, imazapyr, napropamide, and sulfometuron at most rates and dates tested. By 8 WAT, root length, root number, and tensile strength of herbicide-treated centipedegrass sod did not differ from that of the untreated sod except for those plots treated with bensulide or imazapyr. Chemical names used: 6-chloro-N-ethyl-N' -(1-methylethyl) -1,3,5-triazine-2,4 -diamine (atrazine); 2-(3,5-dichlorophenyl) -2-(2,2,2-trichloroethyl) oxirane (tridiphane); O,O -bis(l-methylethyl)S-[2-[(phenylsulfonyl) amino] ethyl] phosphorodithioate (bensulide); dimethyl 2,3,5,6 -tetrachloro-1,4 -benzenedicarboxylate (DCPA); methyl 3-[[(4-methoxy-6-methyl-1,3,5-triazin-2-ylaminocarbonyl]aminosulfonyl]-2-thiophenecarboWlate (DPX-6316); (&)-2-[4,5 -dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl] -3-pyridinecarbolic acid (imazapyr); 2-[4,5-dihydro-4 -methyl-4 -(1-methylethyl) -5-oxo-W-imidazol-2-yl]-3 -quinolinecarboxylic acid (imazaquin); N,N-diethyl-2-(1-naphthalenyloxy)propanamide (napropamide); 3-[2,4-dichloro-5 -(1-methylethoxy) phenyl]-5-(l,l-dimethylethyl)-1,3,4 -oxadiazol-2-(3H) -one (oxadiazon); N-(1 -ethylpropyl)-3, 4-dimethyl-2,6-dinitrobenzenamine (pendimethalin); .2-[1-(ethoxyimino) butyl]-5-[2-(ethylthio) propyl]-3-hydroxy-2 -cyclohexen-1-one (sethoxydim); 6-chloro-N,N'-diethyl-1,3,5-triazine-2)4-diamine (simazine); 2-[[[[(4,6-dimethyl-2-pyrimidinyl)amino]carbonyl] amino] sulfonyl] benzoic acid (sulfometuron).
Lambert B. McCarty and Daniel L. Colvin
Buffalograss [Buchloe dactyloides (Nutt.) Engelm.] is a turfgrass species traditionally adapted to low-rainfall areas that may incur unacceptable weed encroachment when grown in higher rainfall areas such as Florida. An experiment was performed to evaluate the tolerance of two new buffalograss cultivars, `Oasis' and `Prairie', to postemergence herbicides commonly used for grass, broadleaf, and sedge weed control. Twenty to 40 days were required for each cultivar to recover from treatment with asulam, MSMA, and sethoxydim (2.24, 2.24, and 0.56 kg-ha-l, respectively). Other herbicides used for postemergence grass weed control (metsulfuron, quinclorac, and diclofop at 0.017, 0.56, and 1.12 kg·ha-1, respectively) did not cause unacceptable buffalograss injury. Herbicides used for postemergence broadleaf weed control, triclopyr, 2,4-D, sulfometuron, dicamba (0.56, 1.12, 0.017, and 0.56 kg·ha-1, respectively), and a three-way combination of 2,4-D + dicamba + mecoprop (1.2 + 0.54 + 0.13 kg·ha-1), caused 20 to 30 days of unacceptable or marginally acceptable turfgrass quality, while 20 days were required for `Prairie' buffalograss to recover from atrazine treatments. `Oasis' buffalograss did not fully recover from 2,4-D or 2,4-D + dicamba + mecoprop through 40 days after treatment. Herbicides used for postemergence sedge control, bentazon and imazaquin, caused slightly reduced, but acceptable, levels of turf quality in both cultivars throughout the experiment. Chemical names used: 6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine (atrazine); methyl[(4-aminophenyl)sulfonyl]carhamate (asulam); 3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide (bentazon); 3,6-dichloro-2-methoxybenzoic acid (dicamba); (±)-2-[4-(2,4-dichlorophenoxy)phenoxy]propanoic acid (diclofop); 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylic acid (imazaquin); (±)-2-(4-chloro-2-methylphenoxy)propanoic acid (mecoprop); 2-[[[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino]carbonyl]amino]sulfonyl]benzoic acid (metsulfuron); monosodium salt of methylarsonic acid (MSMA); 2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one(sethoxydim); 2-[[[[(4,6-dimethylethyl-2-pyrimidinyl)amino]carbonyl]amino]sulfonyl]benzoic acid (sulfometuron); [(3,5,6-trichloro-2-pyridinyl)oxy]acetic acid (triclopyr); (2,4-dichlorophenoxyl)acetic acid (2,4-D); 3,7-dichloro-8-quinolinecarboxylic acid (quinclorac).
Joe E. Toler, Thomas G. Willis, Alan G. Estes, and Lambert B. McCarty
weed management since the 1980s with the use of products such as metsulfuron and sulfometuron for broad-spectrum weed control in warm-season turfgrasses. This study demonstrates the effectiveness of several SU herbicides for postemergent annual
M. Lenny Wells and Eric P. Prostko
.G. 2000 Temperature effects of atrazine and imazapyr on soils Water Air Soil Pollut. 118 169 178 LaRossa, R.A. Schloss, J.V. 1984 The sulfonylurea herbicide sulfometuron is an extremely potent and selective inhibitor of acetolactate synthase in Salmonella
Jared A. Hoyle, J. Scott McElroy, and Elizabeth A. Guertal
Survey Center, Lincoln, NE Wehtje, G. Dickens, R. Wilcut, J.W. Hajek, B.F. 1987 Sorption and mobility of sulfometuron and imazapyr in five Alabama soils Weed Sci. 35 858 864 Wehje, G.R. Gilliam, C.H. Hajek, B.F. 1993 Adsorption, desorption, and leaching