• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.1
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• pp.29-38
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• 1999

Three kinds of soil surface applied herbicides and three kinds of foliage applied herbicides were used to study weed control effect, appropriate concentration, phyto-toxicity against trees and economical efficiency of weed control on trees, Pinus thunbergii, Picea abies, Chamaecyparis obtusa, Quercus accutissima, and Fraxinus rhynchopylla in a nursery. The results were obtained as follows; 1.The control effect of the soil surface applied herbicides showed that the three herbicides; Alachlor, Pendimenthalin and Simazine were alike in their holding effect of weed development, and the sensibility of weed spp. on the herbicides was different. The mean control effect was 58~89%. 2. The weed control effect of the foliage applied herbicides demonstrated that Paraquat dichloride was the best of 84~95% and followed by Glufosnate ammonium and Glyphosate. Especially when the half of its standard amount was treated, the effect of Paraquat dichloride was higher than the other herbicides. 3. Generally, the weed control effect became better as the concentration of the herbcide getting higher. As the concentration of the herbicide got higher, the restraining effect of weed development was continued for a long time in the soil surface applied herbicides, while the weed control effect appeared earlier in the foliage applied herbicides. 4. As the result of the soil surface treatments, 20% of short seedings of Fraxinus rhychopylla treated with twice amount of standard Alachlor died and the rest seeding showed low growth. In the other treatments, there was neither harmful effect of herbicides on the seedings nor growth decrease of them compared to those weeded by men. 5. When treated with foliage applied herbcides, leaves were partially of and discolorated in most treatments. About 0.4~6.2% of Fraxinus thynchopylla, which had short seedings died, and there was no difference in growth with the other treatments. 6. The herbicides showed better economical efficiency over 68% than weed control by men. Especially, Alachlaor of the soil surface applied herbicides showed the highest efficiency(77.6%), while Paraquat dichloride of the foliage applied herbicides was the best(70.3%)..

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.3
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• pp.5-11
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• 1978

Since 1970, herbicides have been widely used in the crop production, especially in paddy field in Korea. In 1978, both preemergence and postemergence type herbicides are applied in the approximately 70% of total paddy field and 15% of upland to control weeds. Most herbicides control annual weeds effectively, but perennials have been problems in the paddy field. Under upland conditions, effectiveness of herbicides varies depending on many environmental conditions (soil moisture, soil physical properties, temperature, etc.) as well as uniform application of appropriate amounts of herbicides. In Korea, many research works have been concentrated on the screening of new herbicides in terms of herbicide effectiveness and yield or phytotoxicity of crops, and especially on the paddy field. However, physiological aspects of herbicidal action in plant and interaction of herbicides with the environments have not been studied approximately. Therefore, researches on the uptake of herbicides and the influence of herbicides on the physiological phenomena such as photosynthesis, respiration, nutrient uptake etc., to control troublesome perennial weeds in the paddy field are needed in future. Also some researches are needed to improve effectiveness of herbicirdes under upland conditions.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.3
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• pp.31-46
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• 1978

In order to secure the proper use of herbicides that are frequently used in Korea, the behavior of herbicides in various type of soil were studied. This study includes the variation of phytotoxicity, leaching and movement, and residual activity period of herbicides depending upon the type of soil etc. Experiments were also conducted to establish a guideline for the selection of herbicides according to the type of soil and the proper use of each herbicide in various type of soil in Korea. Experimental results showed that the behavior of herbicides could be characterized based on the series or kind of herbicides and devided into two major groups. One group (nitrofen. CNP, benthiocarb and butachlor) of herbicides showed relatively little crop injury and was very dependable. The action of this group was not remarkably influenced by soil components, rainfall and the quantity of herbicide used with the type of soil that had small adsorption capacity such as most of soil in Korea. The other group(simazine, 2, 4-D. linuron, alachlor and simetryne) showed a wide variation in it's action and retained potentially injurious effect. This group was very susceptable to using condition as well as the type of soil itself. Based on the results of various experiments the disappearance of the residual activity period of major herbicides used in upland and paddy field and the related factors were explained. It is believed that the results of this study can be used as a base for the establishment of a guideline for the proper use of each herbicide and can suggest a direction of developing new herbicides.

• Plant Resources
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• v.7 no.2
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• pp.110-115
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• 2004

This study was conducted to evaluate the effect of herbicides on weed control, growth characteristics and yield in flax, after direct seeding it to the field, the herbicides treated had no effect on the emergence period. The major weeds were decreased some what more with mecoprop-wp, herbicide than the other herbicides and by hand weeding. Mecoprop-wp and simazin-wp were had no injury but sethoxydim-EC and 2.4-D-wp were slighthy harmful for the flax with recommended concentration, On the other hand, all herbicides were harmful in the double dosage level

• Korean Journal of Weed Science
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• v.18 no.2
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• pp.85-94
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• 1998

Herbicides play a very important role in modern agriculture. However, the herbicide applied to the agricultural field may accumulate in the field, converting the advantages to environment pollution. Many small animals in the ecosystem such as alderfly, earthworm, butterfly, loach, frog, firefly, some birds and aquatic organisms have been known to disappear gradually. In addition, several behavior of herbicides including adsorption by soil, movement by water, photodecomposition, volatilization to air, absorption by plant, metabolism by soil microorganisms and so on, are proceeded while the herbicide remained in the environment. In this review, fate and behavior of herbicides in the environment and their effect on ecosystem after their application are focused on four aspects : the first is the absorption and metabolism of herbicides by plant; the second is the residues of herbicides in soil and water environments: the third is the accumulation and release of herbicides in aquatic organisms and the fourth is the translocation of herbicides in model agricultural ecosystem. Many factors may affect the behavior and fate of herbicides after their application, climatic conditions and soil properties seem to be the most important. Therefore, the fate and behavior of herbicide in Taiwan, located on subtropical region, may differ from those in Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.3
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• pp.2-4
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• 1978

Some of the remarkable accomplishments mentioned in the special lecture recalling 38 years of my research on the development of herbicides can be summarized as follows; 1) The physiology, movement in the soil, and decomposition and/or inactivation of the phenoxy and other herbicides by the invention of the Raphanus test were elucidated. And these findings led to the establishment of the theory of herbicidal treatment layer with the result of the origination of the application of PCP in flooded lowland paddy, which opened new era of soil application of herbicides in lowland paddy. 2) The granulation of herbicides for lowland paddy including PCP urea was developed. 3) The fact that propanil has generic selectivity in gramineae was found. And propanil was distributed in rice growing regions of the world. In addition, satanil for upland and propanil/NAC for flooded lowland paddy, propanil mixtures, were developed. 4) 15 kinds of new herbicides derived from plant hormones developed in my laboratory were develop ed, and the research trends in the future were presented.

• Bulletin of the Korean Chemical Society
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• v.20 no.10
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• pp.1165-1171
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• 1999

The analysis of trace herbicides using the on-line SPE-HPLC system and a photochemical reaction was studied. 18 compounds of herbicides including eight triazines, six phenoxy acids and esters, and four other herbicides were examined. The on-line SPE-HPLC system developed for selection of eluting solvent improved chromatographic efficiency. The recoveries of herbicides were higher than 77%. With 100 mL tap water samples, the detection limits for all analytes were in the 0.1-2.3×10-10 M range. Detection was done by a UV or fluorescence spectrometer after photochemical reaction at the end of the column with 2W or 450W mercury lamp. Without a photochemical reaction, all compounds responded to 230 nm UV detector, but phenoxy acids and esters were weakly detected. However, with a photochemical reaction, these compounds were selectively detected at 320 nm wavelength of UV absorption and 400 nm emission of the fluorescence detectors. This method can be used for the analysis of environmental water containing herbicides at trace levels.

• Korean Journal of Weed Science
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• v.4 no.1
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• pp.96-106
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• 1984

Changes in weed floras and development of plant resistance to herbicides seemed to be closely related with increased and repeated use of herbicides. Herbicide use increased from 5% of the total consumption of pesticide in 1950 to 45% in 1976 in world basis. About 200 herbicides have been introduced to agriculture so as to control about 206 weed species which have been recorded important to human beings. In Korea, there was about 351 times in increased use of herbicides from 1966 to 1982. Interspecific selection by herbicide is mainly responsible for changes in weed floras and resulted in varying tolerance or susceptibility to herbicides, together with the changes of agricultural practices. The present trend toward continuous cereal cultivation throughout world will lead to type of changes in weed floras favorable to therophyte which can survive under unfavorable conditions as seeds rather than the types of geophyte which can survive unfavorable seasons as buds placed below soil surface. However, geophyte such as Sagitaria pygmaea, and Scirpus jurtcoides, and Cyperus rotundus and Cynodon dactylon in temperate warm climate become severe paddy weeds, presumably because of the removal of annual weeds by herbicides. Since differential tolerance to 2,4-D was firstly reported in Agrostis stolofera, about 30 species of weeds in 18 genera are presently known to have developed resistance to triazine herbicides. Resistance of weed biotypes to triazine herbicide is not mainly due to limited absorption and translocation or to the difference in metabolism, but is the result of biochemical changes at the site of metabolic activity, such as a loss of herbicide affinity for triazine binding site in the photosystem II complex of the chloroplast membrane. Genetical study showed that plastid resistance to triazine was wholly inherited through cytoplasmic DNA in the case of Brassica campestris. Plant tissue culture method can be utilized as an alternate mean of herbicide screening and development of resistance variants to herbicides as suggested by Chaleff and Parsons. In this purpose, one should be certain that the primary target process is operational in cell culture. Further, there are a variety of obstacles in doing this type of research, particularly development of resistance source and it's regeneration because cultured cells and whole plants represent different developmental state.

• Bulletin of the Korean Chemical Society
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• v.24 no.9
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• pp.1319-1323
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• 2003

This paper presents a successful demonstration of the on-line coupling of MEKC (micellar electrokinetic chromatography) to ESIMS (electrospray ionization mass spectrometry) for the quantitative analysis of seven s-triazine herbicides. The on-line MEKC-ESIMS was used to determine the structure of CE-separated peaks of seven triazine herbicides. The mixture of triazine herbicides was separated in a 20 mM sodium borate buffer (pH 8.5) containing 15 mM sodium dodecylsulfate (SDS) by using a bare fused-silica capillary. Electrospray ionization mass spectrometer was operated in the positive-ion mode when the mass spectra of seven triazine herbicides were observed from each peak, and the solution of water-methanol-formic acid (50/49/1 v/v/v) was used as a sheath liquid. The effects of SDS concentration, the run buffer pH, and the electric field on the separation of seven s-triazine herbicides were investigated. The MEKC-ESIMS detection showed 5 to 10 times higher sensitivity compared to the MEKC-UV detection. In addition, it did not need any pretreatment step.

• Korean journal of applied entomology
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• v.22 no.2 s.55
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• pp.147-159
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• 1983

In general, herbicides have been classified according to selectivity, mobility. time of application, methods of application, mode of action and chemical property and structure. However, there was no generally accepted classification system for practical use in the field. The primary processes affected by the majority of herbicides are the growth process through cell elongation and/or cell division, the photosynthetic process specifically the light reaction, the oxidative phosphorylation and the integrity of the membrane systems. The usual approach in the study of the mechanism by which herbicides kill or inhibit the growth of plants is to initially determine the morphological phototoxicity systems, The mechanism by which a herbicide kills a plant or suppresses its development is actually the resultant effect of primary and secondary(or side) effects. In most instances, the death of the plant is due to the secondary effects. To induce the desired response, a herbicide must be able to gain entry into the plants and once inside, to be transported within the plant to its site(s) of activity in concentrations great enough. Obstacles to the entry and movement of herbicides in plants are generally classified by leaf and soil obstacles, translocation obstacles and biochemical obstacles, and these obstacles are also strongly influenced by plant species and by environmental factors such as light, temperature, rainfall and relative humidity. And hence, in most instances, results obtained from laboratory or greenhous vary from those of field experiment. Author attempted to classify herbicides from the field experiment using the two-dimensional ordination analysis to obtain practical information for selecting effective herbicides or to choose effective herbicide combinations for increasing herbicidal efficacy or reducing the chemical cost. Based on this two-dimensional diagram, desired herbicides or combinations were selected and further investigated for the interaction effects whether these combinations are synergistic, additive or antagonistic. From the results, it was concluded that these new approach could possibly be give more comprehensive informations about effective use of herbicide than any other systems.