• The Korean Journal of Pesticide Science
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• v.4 no.2
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• pp.72-75
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• 2000

3,4-Dimethyl-N-[4-chloro-2-fluoro-5-{(pyrazolylmethyl)oxy}phenyl]maleimides or 3,4,5,6-tetrahydro-N-[4-chloro-2-fluoro-5-{(pylazolylmethyl)oxy} phenyl]phthalimides were prepared and evaluated their herbicidal activities under paddy conditions. Those compounds which have N-methyl-5-pyrazolylmethyloxy moiety showed good tolerance in transplanted rice and strong herbicidal activities on barnyardgrass below 60 g/ha of dose.

• The Korean Journal of Pesticide Science
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• v.11 no.2
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• pp.67-71
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• 2007

Nobel series of 5-benzyloxymethyl-3-(thiophen-5-yl)-1,2-isoxazoline derivatives were designed and synthesized. The herbicidal activities of these compounds to main dominant weeds to these compounds were evaluated in pot tests that simulated rice paddy conditions. Most of the compounds showed high herbicidal activity to main dominant weeds occurring in rice field without the serious rice injury.

• Journal of Environmental Health Sciences
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• v.26 no.2
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• pp.70-79
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• 2000

This study was done for the purpose of investigating the status of the use and perceptions of pesticides among the farmers who spray them in person. And it was also done to provide the basic statistics for the Agricultural Health Policy and study. Over the part of agricultural area in Kyungju and Ulsan City, Korea, from July to September 1999, 1032 questionnaires were distributed and 561 of them were collected and 447 were analysed. Major results of this study are as follows. The proportion of those who have special location for pesticides storage was only 5.3%, and that of those who lock hte storage location was only 13.6%. As to the treatment of bottles after use, most common response was 'burn in home'(47.7%). Most farmers purchase pesticides through 'pesticide store' or 'Agricultural Cooperatives'. The knowledge and Usage of pesticides depends in large part on experiences. The farmers who cultivate orchard spray pesticides more frequently than those cultivate paddy rice mainly. Most common pesticides in use are oganophosphates and carbamates. And also the pesticides that contains so-called 'Environmental Hormone' are used. The perception about the hazards of pesticides is rather superficial and insufficient. 'Herbicide(Gramoxon·Paraco)'(38%) is accepted as the most hazardous by farmers.

• Proceedings of the Korean Society of Crop Science Conference
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• 1998.10a
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• pp.210-232
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• 1998

Tong-il, the high-yielding rice variety bred on early 1970, effected a turning point in modern rice production in Korea. As rice production reached the highest record yield in 1978 with HYV, Korea achieved self-sufficiency in domestic supply of rice (or the first time in (her own) history, HYV required high input of fertilizers and pesticides for proving its yielding ability and needed new techniques such as early nursery-planting to prevent chilling damage. But, farm economy did not follow the successful achievement of rice production because of increased farming cost and inflation.'Tong-il variety has been replaced by new high-yielding Japonica varieties from 1980 when record-low-temperature during summer months had persisted. Also, the cooked rice of Tong-il variety did not agree with the appetite of Korean people. Though the hectarage of Tong-il rice did reduce, farmers applied the same high-input cultural techniques for new Japonica cultivars as did for Tong-il variety. Heavy application of nitrogen fertilizer contaminated surface and ground water with nitrate ions while phosphorous fertilizer was blamed for algae pollution. Frequent spray of pesticide and herbicide reduced significantly the biotic population in paddy ecosystems including insects and soil microorganisms. The new technologies of the 21st century must be directed to produce safe food, to save natural resources, and to preserve a clean environment for human welfare. We need low-input sustainable farming techniques to provide high-yielding crops and to preserve a healthy ecosystem.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.21 no.1
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• pp.20-23
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• 1976

Distribution of underground organs of perennial weeds in soil and ecological control measure were evaluated. Tubers of Cypers serotinus and Sagittaria pygmaea were mostly presented in a shallow depth of 0 to 5cm, however, Potamogeton distinctus's bulbs and Eleocharis kuroguwai's tubers were distributed in the soil at 10 to 20cm. A 20cm autumn plowing was, to some extent, effective to reduce Potamogeton distinctus. The herbicide, avirosan at 3kg/10a alone, was extremely effective in controlling Potamogeton distinctus.

• The Korean Journal of Pesticide Science
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• v.5 no.2
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• pp.33-36
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• 2001

New series of sulfonylureas containing substituted thiophene with 2-chloromethyl-1,3-dioxolane group were prepared, and their herbicidal effects were tested(in vivo) in the upland conditions and in the paddy submerged conditions. The sulfonylureas in which 4,6-dimethoxy- or 4-methyl-6-methoxy group in pyrimidine or triazine ring showed good herbicidal effects at a rate of 0.1 kg/ha. However, they showed weaker herbicidal effects than that of sulfonylureas containing substituted thiophene with 2-fluoromethyl-1,3-dioxolane group in general.

• The Korean Journal of Pesticide Science
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• v.4 no.3
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• pp.15-18
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• 2000

A series of N-{2,4-dichloro-5-(3-pyrazolyl)Phenyl}imides 7 and 8 was prepared and evaluated their herbicidal activities. Those compounds in which either carboxylate or carboxamide moiety is on pyrazole moiety 7c-71 showed no herbicidal activity whereas, the compounds in which trifluoromethyl group is substituted in pyrazolyl moiety showed moderate herbicidal activities against barnyardgrass, monochria and flat-sedge under paddy conditions with good rice tolerance at rate 63-250 g/ha.

• Korean Journal of Weed Science
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• v.31 no.1
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• pp.1-7
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• 2011

It was a method of weed removing, called as whagyeongsoonoobeob. Namely, the Hwanoobeob was the weeding method came from "Jeminyosool" in old China, and had been descended to "Wibinmyeongnonggi", "Nonggajibseong" and "Gwanongsocho" in the $16\sim18^{th}$ century of our country. The method was applied to rice paddy after applying direct-seeding, burning by unit before watering to remove weeds and to save rice plants. It would be applied with a method of using non-selective herbicide such as paraquat and oxyfluorfen, or radiation treatment, as a simple and safe weed removing method.

• The Korean Journal of Pesticide Science
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• v.21 no.1
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• pp.68-74
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• 2017

An analytical method for detecting metamifop residue in paddy water, soil, and rice with high performance liquid chromatography (HPLC) was developed. Water was extracted with ethyl acetate before analyzing by HPLC. Soil residues were extracted with acetone under acidic condition and after purifying with $Extrelut^{(R)}$ NT, and silica SPE, the residue was analyzed by HPLC. For residue analysis in rice, the procedure involved extraction with acetone, purification with $Extrelut^{(R)}$ NT, partitioning between acetonitrile/hexane, purification with silica SPE cartridge, and analysis by HPLC. The limit of detection (LOD) was 1.0 ng, limit of quantitation (LOQ) was 3.0 ng, and method limit of quantitation (MLOQ) were 0.001 mg/L for paddy water, 0.01 mg/kg for rice and soil, respectively. Standard calibration curve shows linearity from 0.05 mg/kg to 5.0 mg/kg ($R^2=0.9999$). The recoveries in fortified paddy water were $91.3{\pm}3.5%$ (0.01 mg/L level) and $93.2{\pm}6.3%$ (0.05 mg/L level). The recoveries in fortified paddy soils were $92.5{\pm}4.0%$ (0.1 mg/kg level) and $92.7{\pm}4.0%$ (0.5 mg/kg level) in soil A, while, $102.3{\pm}4.4%$ (0.1 mg/kg level) and $98.9{\pm}7.9%$ (0.5 mg/kg level) in soil B, respectively. The recoveries in fortified rice were $93.0{\pm}6.9%$ (0.1 mg/kg level) and $85.0{\pm}3.5%$ (0.5 mg/kg level). This method was proved to be effective and can be used to determine the metamifop residue in paddy water, paddy soil, and rice.

• Weed & Turfgrass Science
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• v.6 no.3
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• pp.203-211
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• 2017

This study was conducted to investigate the phytotoxicity of main rice varieties and control efficacy of HPPD inhibitor to major paddy weeds at the time of temperature rise due to climate change. Phytotoxicity of herbicide to rice was increased as temperature was increased, and more severe in root than shoot. The phytotoxicity of japonica rice cultivars for the rice were mild enough to recover. However, glutinous rice, super high yield rice, and Tongil rice varieties were damaged enough to decrease the yield. Shindongjinbyeo transplanted by June 15, showed phytotoxicity enough to recover. However, in the rice field on June 30 and on July 15, the rice showed a remarkable inhibition. The control effect of Monochoria vaginalis and Scirpus juncoides was more than 90% under the temperature condition controlled artificially. However, Echinochloa oryzicola was controlled 40% at $27.5^{\circ}C$, which is a high temperature condition. In rice fields with different transplanting times, annual weeds except for E. oryzicola were highly controlled by 90% or more regardless of the time of transplanting.