Rates Of Sethoxydim Research Articles

Red Rice (Oryza sativa) Control Options in Soybeans (Glycine max)

Both alachlor at 3.6 kg ai/ha and metolachlor at 2.8 kg ai/ha applied preplant incorporated consistently controlled red rice 82% and 90%, respectively, over a 3-yr period. Averaged across years, only mefluidide at 0.14 kg ai/ha plus bentazon at 0.84 kg ai/ha, haloxyfop at 0.28 kg ai/ha, and quizalofop at 0.14 kg ai/ha applied postemergence controlled red rice comparable to the preplant herbicide treatments. High rates of sethoxydim and fluazifop (0.56 kg ai/ha), haloxyfop (0.28 kg ai/ha), and quizalofop (0.14 kg ai/ha) were needed to obtain soybean yields equivalent to alachlor and metolachlor.

The Impact of Adjuvants on Herbicide Antagonism

Adjuvants are used to improve spray delivery, to increase spray retention on weed foliage, and to enhance foliar penetration by postemergence herbicides for increased herbicide efficacy. Numerous factors govern adjuvant efficacy, including the specific herbicide, plant species, and environmental conditions. Adding superior surfactants as adjuvants to a sethoxydim tank mix with Na-bentazon may overcome the Na-bentazon antagonsim of sethoxydim activity by facilitating increased sethoxydim absorption and by masking the antagonism similar to increasing the sethoxydim rate. Herbicides such as Na-bentazon contribute alkaline or alkaline earth cations that can form salts of a weakly acidic herbicide such as sethoxydim that are not absorbed readily by the plant. Adding abundant ammonium from ammonium sulfate or other sources may prevent and/or may overcome this antagonism.

Weed Control in Soybeans (Glycine max) with Reduced Rates of Postemergence Herbicides

Field studies were conducted at three sites in Missouri in 1986 and 1987 to evaluate the performance of below-label rates of bentazon, acifluorfen, and chlorimuron tank mixed with sethoxydim and applied to soybeans 7 and 14 days after planting to evaluate broadleaf and grass weed control and weed seed production. Sequential applications of 0.25X-labeled rates of all three broadleaf herbicides tank mixed with 0.5X sethoxydim rates controlled giant foxtail, velvetleaf, and common cocklebur equivalent to one application of standard-labeled rates of the same tank mixes. Single applications of below-labeled rates of the postemergence herbicides did not control weeds, and soybean yields were not equal to sequential 0.25X or single full-rate treatments. A preemergence treatment of clomazone plus imazaquin applied at labeled rates controlled weeds, and soybean yields were equal to a handweeded check in both years at all test locations. Weeds survived and produced seed to reinfest the plots the following year unless nearly 100% control was achieved.

Proso Millet (Panicum miliaceum) Control in Corn (Zea mays) by Postemergence-Directed Herbicides

Proso millet (Panicum miliaceumL. # PANMI) was controlled in corn (Zea maysL. ‘Pioneer 3747’) with postemergence-directed herbicides applied following a standard preplant-incorporated application of butylate[S-ethylbis(2-methylpropyl)carbamothioate] plus dichlormid (2,2-dichloro-N,N-di-2-propenylacetamide) plus cyanazine {2-[[4-chloro-6-(ethylamino)-1,3,5-triazin-2-yl]amino]-2-methylpropanenitrile}. Postemergence-directed applications of ametryn [N-ethyl-N′-(1-methylethyl)-6-(methylthio)-1,3,5-triazine-2,4-diamine], cloproxydim {(E,E)-2-[1-[[(3-chloro-2-propenyl)oxy]imino]butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one}, butyl ester of fluazifop {(±)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy] propanoic acid}, butyl ester of fluazifop-p {(R)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy] propanoic acid}, glyphosate [N-(phosphonomethyl)glycine], methyl ester of haloxyfop {2-[4-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy]propanoic acid}, and sethoxydim {2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one} in 40-cm-tall corn gave greater than 90% control of 5- to 15-cm-tall proso millet while causing little or no corn injury at selected rates. Season-long proso millet control was obtained with sethoxydim at rates as low as 56 g ai/ha with no visible corn injury. Unacceptable injury to 40-cm-tall corn occurred with all but the lowest rate of sethoxydim (56 g ai/ha) when a crop oil concentrate was used. Sethoxydim applied as a directed spray at rates up to 110 g ai/ha plus 1.25% (v/v) crop oil concentrate did not injure 60-cm-tall corn.

Centipedegrass Tolerance to Postemergence Grass Herbicides

Abstract The phytotoxicity of single and sequential treatments of sethoxydim and fluazifop at 0.10, 0.20, and 0.30 kg·ha−1; haloxyfop, xylafop, fenoxaprop, and SC-1084 at 0.07, 0.15, and 0.30 kg·ha−1, on centipedegrass [Eremochloa ophiuroides (Munro.) Hack.] was determined. Turf color generally was unaffected by sethoxydim application except for a slight discoloration at 14 days after treatment (DAT) with the high rate. Recovery was evident from all rates of sethoxydim by 28 DAT. Turf density was similar to untreated control at 42 DAT. Single applications of fenoxaprop and SC 1084 at 0.07 kg·ha−1 initially caused severe discoloration; however, recovery was evident by 42 DAT. Density also was unaffected at this time. Unacceptable turf color and density were observed with single and sequential applications of fluazifop, haloxyfop, xylafop, and with sequential application of SC 1084 and fenoxaprop. Chemical names used: (2-[l-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-l-one (sethoxydim); (±)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxyl]phenoxy]propanoic acid (fluazifop); 2-[4-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl]oxy]-phenoxyl]propanoic acid (haloxyfop); (2-[4-[(6-chloro-2-quinoxalinyl)-oxy]phenoxyl]propanoic acid (xylafop); (±)-2-[4-[(6-chloro-2-benzoxazolyl)oxy]phenoxy]propanoic acid (fenoxaprop); and methyl-3-hydroxy-4-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy]-pentanoate (SC-1084).

Tolerance of Red Fescue (Festuca rubra) and Bentgrass (Agrostisspp.) to Sethoxydim

Sethoxydim {2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one} is used to control weedy grasses in red fescue (Festuca rubraL. # FESRU andF. rubrassp.commutata), an important seed crop in Oregon. The sethoxydim rate required to reduce growth rate of 11 cultivars of red fescue and four cultivars of bentgrass (Agrostis tenuisSibth. # AGSTE andA. stoloniferaL. var.palustris# AGSST), a common contaminant in red fescue fields, by 50% (GR50) was determined in greenhouse and laboratory experiments. Field experiments compared only red fescue cv. ‘Pennlawn’ and bentgrass cv. ‘Penncross'. The GR50values for Pennlawn red fescue in the field, the greenhouse, and the laboratory were 30 kg ai/ha, 15 kg/ha, and 5300 μM, respectively. Penncross bentgrass was approximately 400, 1400, and 12 900 times more susceptible than Pennlawn red fescue in the field, in the greenhouse, and in laboratory experiments, respectively. Plants were at different growth stages in the different experiments. The xylene and surfactant used as a solvent for the technical grade sethoxydim was as toxic to red fescue without sethoxydim as when sethoxydim was included. Cultivars of red fescue differed in their response to sethoxydim, but cultivars of bentgrass did not. The GR50's of other species tested in the greenhouse were >4 kg/ha for annual bluegrass (Poa annuaL. # POAAN), 0.22 kg/ha for tall fescue (F. arundinaceaSchreb. # FESAR), 0.37 kg/ha for downy brome (Bromus tectorumL. # BROTE), and 0.017 kg/ha for Italian ryegrass (Lolium multiflorumLam. # LOLMU).

Potential safeners for protecting sorghum (Sorghum bicolor (L.) Moench) against chlorsulfuron, fluazifop‐butyl and sethoxydim*

Summary:In greenhouse studies, the efficacy of the herbicide safeners NA(1,8‐naphthalic anhydride), R‐25788 (N,N‐diallyl‐2,2‐dichloroacetamide), cyometrinil and CGA‐92194 [N‐(1,3‐dioxolan‐2‐yl‐methoxy)imino‐benzeneaceto‐nitrile] in protecting grain sorghum (Sorghum bicolor (L.) Moench, cv. ‘Funk G623’) against injury from pre‐emergence or early post‐emergence applications of the herbicides chlorsulfuron, fluazifop‐butyl and sethoxydim was examined. NA as a seed dressing at 0·5 or 1·0% (w/w) was the most effective of the four safeners and offered partial to good protection to sorghum against injury from the lower rates of pre‐emergence applications of all three herbicides. R‐25788 was totally ineffective as a sorghum protectant against fluazifop‐butyl injury but it did antagonize partially the injurious effects of the lower rates of sethoxydim and chlorsulfuron on sorghum. Cyometrinil and CGA‐92194 offered partial protection to sorghum against injury from the lowest rate of all herbicides but their efficacy against higher rates of the three herbicides was very limited. None of the four safeners was effective in protecting grain sorghum against injury from post‐emergence applications of the three herbicides tested.

Influence of Application Variables on Antagonism Between Sethoxydim and Bentazon

The effects of sethoxydim {2-[1-(ethoxyimino) butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexene-1-one} rate, order, and timing of sequential herbicide applications, and the addition of oil concentrate on sethoxydimbentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H-one 2,2-dioxide] antagonism were studied on broadleaf signalgrass [Brachiaria platyphylla(Griseb.) Nash. ♯3BRAPP], fall panicum (Panicum dichotomiflorumMichx. ♯ PANDI), and large crabgrass [Digitaria sanguinalis(L.) Scop. ♯ DIGSA] in field experiments during 1980 and 1981. Tank-mixing bentazon with sethoxydim reduced control of these species compared to applications of sethoxydim alone. Sequential applications of the herbicides prevented the antagonism. Variations in time between and order of sequential applications had no consistent effect on efficacy. Increases in sethoxydim rate reduced the severity of the antagonism in some cases, while the addition of oil concentrate had no effect.