• Korean Journal of Weed Science
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• v.4 no.2
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• pp.188-193
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• 1984

Interactions of herbicide mixtures were assessed for effective control of annual and perennial paddy weeds by isobole method(90% control) using Echinochloa crusgalli Beauv. var. oryzicola Ohwi, Scirpus hotarui Ohwi, Sagittaria pygrnaea Miquel, and Cyperus serotinus Rottb which are dominated in the paddy field of Korea. Mixture of butachlor and pyrazolate showed additive effect for control of E. crusgalli Beauv. var. oryzicola Ohwi, S. hotarui Ohwi and C. serotinus Rottb, but synergistic effect for control of S. pygmaea Miquel. Interaction of bifenox and bromobutamide showed synergistic effect to E. crusgalli Beauv. var oryzicola Ohwi and C. Serotinus Rottb, but slightly antagonistic effect to S. pygmaeo Miquel.

• Korean Journal of Weed Science
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• v.3 no.2
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• pp.199-207
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• 1983

To select appropriate herbicides for adzukibean and mungbean, a series of experiments was carried out in both field and pot from 1980 to 1983. Tolerance to the herbicides tested was highest in soybeans and followed by mungbean and adzukibean in the order. Pre-emergence herbicides showed relatively low phytotoxicity were chlorambem, linuron, and metribuzin for adzukibean and alachlor and butachlor for mungbean. Post-emergence herbicides showed no external phytotoxicity for adzukibean and mungbean were alloxydim, Dowco 453, fluazifop, etc.. For mungbean, terbutryn (1.5 kg, a.i./ha) which is pre-emergence herbicide showed the best weeding control efficacy but some possible phytotoxicity. Among post-emergence herbicides, acifluorfen (300 g, a.i./ha) showed the best weeding efficacy with no yield reduction though some phytotoxicity which recovered within 20 days. Compared to single herbicide application, the mixture or systemic treatments of herbicides showed much higher weeding control efficacy and seed yields: the systemic treatments of linuron (500 g, a.i./ha) / Dowco 453 (180 g, a.i./ha) or linuron (500 g, a.i./ha) / fluazufop (260 g, a.i./ha) for adzukibean and the mixture treatment of alachlor (1.31 kg, a.i./ha) / acifluorfen (150 g, a.i./ha) for mungbean, respectively.

• Korean Journal of Weed Science
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• v.32 no.2
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• pp.133-138
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• 2012

This study was conducted to investigate the herbicidal activity against resistant biotype on sulfonylurea (SU) herbicides such as Scirpus juncoides and Monochoria vaginalis at the glasshouse and paddy rice cultivation area. In order to investigate resistance breakability against SU-resistanted annual weeds, new rice herbicides containing tefuryltrione [p-hydrophenyl pyruvate dioxygenase (HPPD) inhibitor] were tested. In both lab test and field experiment, tefuryltrione mixture, 4-HPPD inhibitor had shown excellent efficacy with a bleaching on the leaves of resistant annual weeds at early time after treatment and showed excellent persistance. Especially, tefuryltrione mixture had shown excellent controlling effect on annual and perennial SU-resistant S. juncoides in the regional field experiment. In phytotoxicity test, this tefuryltrione mixture had shown good selectivity to common rice species.

• BMB Reports
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• v.30 no.1
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• pp.13-17
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• 1997

The inhibitory effect of herbicides such as sulfonylurea derivatives, imidazolinones and pyrimidylsalicylate has been examined on the purified valine sensitive acetolactate synthase (ALS) from Serratia marcescens. The concentration of sulfometuron methyl which inhibits 50% of the ALS activity was 2.5 mM. The required concentrations of triasulfuron, primisulfuron methyl and imazaquin for the 50% inhibition of the ALS activity were 1 mM. The resistance of Serratia ALS to sulfometuron methyl, imazapyr and imazaquin is similar to that of E. coli ALS 1. However, pyrimidylsalicylate showed a potent inhibitory effect on the Serratia ALS almost 13 times more potent than on E. coli ALS II, which is known as herbicide-sensitive isozyme. The inhibitory mode was competitive against pyruvate. 150 value was determined to be $17{\mu}M$ in an assay mixture containing 20 mM pyruvate, and the $K_1$, value was calculated to be $0.4{\mu}m$ from the modified double reciprocal plot of 1/V versus $1/S^2$.

• Korean Journal of Weed Science
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• v.12 no.2
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• pp.132-143
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• 1992

The study was conducted to find out synergistic effects by interaction on the basis on anatomical changes between paddy rice and weed species by mixture use of oxyfluorfen and bensulfuron at 0, $10^{-6}$ and $10^{-4}$M, respectively. Tissues were sampled at 72 hrs after soaking treatment and prepared for light microscopic examination and sectioned longitudinally and transversely stem into $8{\mu}m$ thick. As the results of microscopic examination, the major response of treated plant involved rupture and constrict in mesophyll cells and epidermal cells, and shrinks in bundle sheath cells by oxyfluorfen and disorganization and swelling in meristems by bensulfuron. Anatomical changes in rice was the least affected by even high concentration and two herbicide mixtures, whereas Echinochloa crus-galli was severely disorganized in meristem regions and ruptured in epidermal cells by mixture use. Monochoria vaginalis was completely ruptured by any treatment concentrations and mixtures. Scirpus juncoides was considerably tolerant to both herbicides and their mixture and was similar to those that occur in rice. Perennial weed, Sagittaria pigmaea was observed vacuolation, non-nucleation of cell, and irregular cell layering but in mixture injury was slight. Cyperus serotinus was severely shrunk and ruptured by mixture treatment. Eventually anatomical variations in all weed species was shown synergistic effect by use of herbicide mixtures.

• Environmental Analysis Health and Toxicology
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• v.18 no.2
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• pp.121-129
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• 2003

The genotoxicity of pendimethalin [N-(l-ethylpropyl)-2, 6-dinitro-3, 4-xylidine, C$\_$13/H$\_$19/N$_3$O$_4$, M.W.=281.3, CAS No. 40487-42-1], one of selective herbicide, was evaluated in bacterial gene mutation system, chromosome aberration in mammalian cell system and in vivo micronucleus assay with rodent. In bacterial gene mutation assay, pendimethalin revealed dose-dependent mutagenic potential in 313 ∼ 5,000 ${\mu}$g/plate of Salmonella typhimurium TA 98 and TA 1537 both in the absence and presence of S-9 metabolic activation system, and TA 100 only in the absence of S-9 mixture. In the TA 1535, slight increase of revertant was also observed in the presence of S-9 metabolic activation system. No mutagenic potential was observed in the TA 1535 without metabolic activation system and TA l00 in the presence of S-9 mixture. In mammalian cell system using Chinese hamster lung (CHL) fibroblast, no clastogenicity of pendimethalin was observed both in the absence and presence of S-9 metabolic activation system in the concentration range of 2.32∼9.28 ${\mu}$g/ml. And also, in vivo bone marrow micronucleus assay, pendimethalin revealed no clastogenic potential in the dose range of 203∼810 mg/kg body weight after oral administration in mice. Consequently, in vitro chromosome aberration with mammalian cells and in vivo bone marrow micronucleus assay revealed no clastogenic potential of pendimethalin. However, pendimethalin revealed mutagenic potential in bacterial gene mutation assay.

• Korean Journal of Weed Science
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• v.4 no.1
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• pp.88-95
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• 1984

The study was intended to analyze the interaction effects of paraquat and oxytluorfen as an orchard herbicide-mixture. Data were prepared from the former report of authors. The algebraic expression for the actions of paraquat and oxyfluorfen on the control percentages of peach orchard weeds, and their interactions were determined from the multiple regression polynomial and plotted in three-dimensional graphs. As a result of treatments by combination of paraquat and oxyfluorfen on the field which was dominated by perennial weeds, the most effective interactions were detected at combination rates of $245\;gHa^{-1}$ paraquat and $470-705\;gHa^{-1}$ oxyfluorfen. However, to develope the long-term weeding-efficacies, the combination rates of paraquat are expected to raise up to $500-700\;gHa^{-1}$, and oxyfluorfen to fit at lower limits of rates, respectively.

• Korean Journal of Weed Science
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• v.3 no.1
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• pp.69-74
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• 1983

The behaviour of mixtures of herbicides was determined to obtain the basic informations about effective herbicide use, enhancing herbicidal efficacy and reducing the chemical cost. Fourteen herbicides with 91 mixed combinations were evaluated by Limpel et al method at the Echinochloa crus galli Beauv-Monochuria vaginalis Presl.-Scirpus hotarui Ohwi (importance values of these weeds were 63%, 16% and 10%, respectively) community type. Thirty eight mixed combinations showed the antagonistic response. Among these 14 mixed combinations including chlormethoxynil + naproanilide mixture were greater than 11% in antagonistic effect. On the other hand, 40 mixed combinations including chlormethoxynil + SW751 mixture showed additive response (${\pm}2%$). For synergistic response, 13 mixed combinations were belonged to this group. Particularly, 3 mixed combinations, chlormethoxynil + butachlor, chlormethoxynil + bifenox and nitrofen + ACN/MCPB/nitrofen mixtures were greater than 11% in synergistic effects. The mixture of thiobencarb + oxyfluorfen was analyzed by isobole technique. This mixture showed the synergistic response and the interaction index was approximately 2. The most optimum mixtur for inducing 90%n weed suppression was 0.012 kg ai/ha for oxyfluorfen and 0.45 kg ai/ha for thiobencarb.

• Korean Journal of Plant Resources
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• v.22 no.4
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• pp.359-363
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• 2009

In order to establish labor-saving culture technology in Tartary buckwheat, three cultural practices: hand planting, drill sowing machine and soil cover direct seeding machine, were compared.The highest grain yield was found in soil cover direct seeding plot with a value of 3.4 g per plant. As a result, grain yield may be estimated to be 113kg in soil cover direct seeding and 80kg in hand scattering. In addition, for the weed control, three herbicide treatments: single use of Alachlor, mixture and combination of Alachlor and Paraquat dichloride were conducted. the mixture showed over 90% weed control value, and the highest grain yield was found in the combination treatment. Combine machine was effective to reduce the ratio of grain loss and working hour by enhancing the working efficiency to 15${\sim}$20min/10a.

• The Korean Journal of Pesticide Science
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• v.6 no.3
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• pp.183-192
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• 2002

Herbicidal effect of KSC-35089, a newly synthesized N-arylphthalimide compound, was examined, and its interaction with quizalofop-P-ethyl when foliar applied as a tank-mixture was evaluated under a greenhouse condition. KSC-35089 showed stronger herbicidal activity on broadleaves than grasses, suggesting that it would be an appropriate partner for non-selective weed control with quizalofop-P-ethyl, a strong grasskilling ageant. In general, the interaction between KSC-35089 and quizalofop-P-ethyl appeared to be additive, which indicates each compound acts on whole plant level independently. This additive interaction was confirmed in a spectrum test using 19 grasses and 26 broadleaves. Under the greenhouse condition, all tested plants were controlled around 90% level through a foliar application with a tank-mixture of KSC-35089 at 64 g ai/ha and quizalofop-P-ethyl at 32 g ai/ha. Further study would be required on the action mechanism of this additive interaction.