• Korean Journal of Environmental Agriculture
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• v.13 no.1
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• pp.60-65
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• 1994

Absorption and translocation of bensulfuron-methyl {methyl 2[[[[[(4,6-dimethoxy-2-pyrimidinyl) amino]carbonyl]amino]sulfonyl]methyl]benzoate} in rice (Oryza sativa L.) as affected by mineral nutrients and mixed herbicides were determined using the $^{14}C-labeled$ herbicide in culture solution. Absorption of $^{14}C-bensulfuron-methyl$ by the root decreased with increasing concentration of bensulfuron-methyl. However, increase in the application concentration did not affect movement of the $^{14}C$ to the shoot. There was no difference in total amount of $^{14}C-bensulfuron-methyl$ taken up between absorption periods of 12 and 48 hours, whereas $^{14}C-bensulfuron-methyl$ translocated to the shoot increased with increasing the absorption period. When bensulfuron-methyl mixtures were applied, butachlor [N-(butoxymethyl)-2-chloro-N-(2',6'-diethylphenyl)acetamide] did not affect absorption and translocation of $^{14}C-bensulfuron-methyl$. However, quinclorac (3,7-dichloro-8-quinoline carboxylic acid) mixed at a high concentration resulted in decrease in absorption and translocation of $^{14}C-bensulfuron-methyl$. Nutritional disorder such as deficient or excess supply of mineral nutrients caused to inhibit absorption of $^{14}C-bensulfuron-methyl$. The greatest decrease and delay of $^{14}C-bensulfuron-methyl$ absorption and/or translocation occurred in N-deficient and S-excess supply conditions.

• The Korean Journal of Pesticide Science
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• v.9 no.3
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• pp.205-213
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• 2005

This study was conducted to evaluate the response of the selected aquatic plants to sulfonylurea(SU)-herbicides, which have been used widely in rice-cultivating areas in Korea, and the possibility of using them as bio-indicator species for biodiversity conservation. The aquatic plants identified in Kangwon province where butachlor have been used extensively for many years were much more varied than those in Chonnam where SU-herbicides have been used extensively for many years. The growth responses of Monochoria korsakowii, Marsilea quadrifolia and Salvinia natans to sulfonylurea herbicides such as bensulfuron-methyl(BSM) and pyrazosulfuron-ethyl(PSE), were much more sensitive than those to butachlor and molinate. The $GR_{50}$ values of BSM and PSE for M. korsakowii, M. quadrifolia and S. natans were relatively very low when compared with those of butachlor and molinate. The number of internode and dry weight of M. quadrifolia which was exposed to herbicides runoff from rice fields were seriously affected. The acetolactate synthase(ALS) activities of M. quadrifolia sensitively inhibited by BSM and PSE were, and $I_{50}$(Inhibition 50%) were 5.6 and 2.1 nM, respectively.

• Journal of Plant Biotechnology
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• v.30 no.1
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• pp.1-6
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• 2003

In an attempt to evaluate the current research status of genetically modified (GM) plants, the scientific research publications in Korea as well as in international SCI journals were screened. About 190 research articles related to the development of GM plants were searched from 10 different domestic journals in the last 12 years (Jan. 1990 to Sept. 2002), The researches in 65 articles were carried out with tobacco plant, 20 with rice, 19 with potatoes, and less then 9 articles from each other plant species, respectively, In total, 38 different plant species were being subjected for the development of GM plants. In particular, there was only one article for each major staple grains such as wheat, barley, soybean, and maize. In more than 47% of total published articles, scientists mainly focused on the basic research such as developing transformation system (46 articles), gene expression study in transgenic plants (34), and vector constructions (10). In addition, 28 articles which main authors are Korean scientists were searched from 11 different international SCI journals. Again, major plants for GM research were tobacco (10) and rice (7). More than 50% of published articles were focused on the basic research, gene expression study with transgenic plants (16). The publications on the research of disease-resistant plants were 7 articles, 3 for the development of stress-resistant and 2 for the herbicide-resistant plants, respectively. It is believed that the last 10 year's investment through government organizations has just strengthen the capacity for the next big stride on agricultural biotechnology in Korea.

• Korean Journal of Weed Science
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• v.30 no.3
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• pp.252-257
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• 2010

The experiments were carried out to develop ecological weed control system in wheat field of rice-wheat cropping system. The results were, depression effect on water foxtail by wheat seeding method decreased the seeding after doing soil rotary by 85% compared with the no practices. The occurrence of Water foxtail was 40 piece $m^{-2}$ on October 16, 29 piece $m^{-2}$ on October 26, and 4 piece $m^{-2}$ when surveying based on the standard of seeding the wheat at 15kg $ha^{-1}$ which decreased as the seeding time got later. According to the wheat seeding quantity 29 piece $m^{-2}$ occurred at 150kg $ha^{-1}$, and 8-11 piece $m^{-2}$ decreasingly at more than 200 kg $ha^{-1}$ of wheat seedlings based on seeding on October 26. As a result of summarizing the above results, crushing the soil by use of rotary before seeding wheat against the end of October, and seeding by increasing the seedling quantity (200 kg $ha^{-1}$) it is judged that the competition damage by weeds including water foxtail can be reduced without any use of herbicide.

• Korean Journal of Environmental Agriculture
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• v.12 no.3
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• pp.239-246
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• 1993

In order to clarify the possible contamination of rice straw used as a crude feed for livestock, Korean native cattle and cow, by pesticides, the samples collected from 21 sites in Korea were analyzed by a multiresidue method for 10 pesticides with GLC to obtain the following results. 1. Detection limits were 0.001ppm in butachlor, 0.002ppm in chlorpyrifos, 0.003ppm in BPMC, pirimiphos-methyl and diazinon, 0.004ppm in fenitrothion, 0.005ppm in phenthoate, 0.009ppm in IBP, 0.015ppm in carbofuran, and 0.03ppm in carbaryl. 2. In recovery tests, 73-101% of the pesticides applied were recovered, the recovery being low in carbofuran and chlorpyrifos. 3. Butachlor, 2-chloroacetanilide herbicide, and BPMC, carbaryl, and carbofuran, carbamate insecticides, were not detected in any sample. 4. In organophosphorus insecticides, the amounts of fenitrothion in sample No. 1, 2, 4, 5, 7, 12, 20 and 21 were in the range of 0.01-0.05ppm, those of phenthoate detected in sample No. 10 and 12 were 0.4 and 0.17ppm, respectively, and those of IBP in all samples, with the exception of sample No. 7, 12, 16, 17, 20, and 21, were in the range of 0.01-0.20ppm. The residues of chlorpyrifos, diazinon, and pirimiphos-methyl were not detected.

• The Korean Journal of Pesticide Science
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• v.4 no.2
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• pp.21-28
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• 2000

A new fourty six 2-(4-(6-chloro-2-benzoxazolyloxy)phenoxy)-N-phenylpro- pionamide derivatives were synthesized and the herbicidal activities against rice plant and barnyard grass with pre-emergence in down land were measured. The structure activity relationships (SAR) between the activities and physicochemical parameters of the substituted(X) N-phenyl group in substrates were analyzed and discussed by Free- Wilson and Hansch method from the basis on the former study (Sung. et. al., 1999). The conditions of selective herbicide activity both the barnyard grass and rice plant are shown that the optimal hydrophobicity, $({\pi})_{opt.}=1.34$ and electron donating with field effect (F<0) of meta and ortho, para-substituted mono or disubstituent on the N-phenyl ring were found to contribute significantly. The herbicidal activities against barnyard grass are roughly the same as the results in up land whereas damage to rice plant in down land more increase than that of up land. Degradation products in water are 2-(4-(6-chloro-2-benzoxazolyloxy)phenoxy)propionic acid ((A)) (obs. pKa=4.35 & obs. logP=4.77) and 6-chloro-2-benzoxazolone (B) (obs. pKa=8.40 & obs. logP=2.90). These results were supposing that the hydrolysis product of substrates, (A) is comparatively absorbed in rice plant but not in barnyard grass. And it is assumed from the SAR equations that the 2,6-dimethyl-4-methoxymethyl group substituent ($pI_{50}=5.41$, 3g/ha) is selected as the most highest herbicidal activity against barnyard grass in green house.

• The Korean Journal of Pesticide Science
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• v.14 no.2
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• pp.95-103
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• 2010

Fomesafen is a selective herbicide, and used to control annual and perennial broad-leaf grass on soybean and fruit fields in USA and China, but not introduced in Korea yet. So, MRL (Maximum Residue Level), and analytical method of fomesafen were not establishment in Korea. Therefore, this experiment was conducted to establish a determination method for fomesafen residue in crops using HPLC-UVD/MS. Fomesafen residue was extracted with acetone from representative samples of five raw products which comprised hulled rice, soybean, apple, green pepper, and Chinese cabbage. The extract was diluted with saline water, and dichloromethane partition was followed to recover fomesafen from the aqueous phase. Florisil column chromatography was additionally employed for final clean up of the extract. The fomesafen was quantitated by HPLC with UVD, using a Shiseido CAPCELL-PAK UG C18 column. The crops were fortified with fomesafen at 3 levels per crop. Mean recovery ratio were ranged from 87.5% for a 0.4 ppm in hulled rice to 102.5% for a 0.4 ppm in apple. The coefficients of variation were ranged from 0.6% for a 2.0 ppm in hulled rice to 7.7% for a 0.04 ppm in green pepper. Quantitative limit of fomesafen was 0.04 mg/kg in representative 5 crop samples. A LC/MS with selected-ion monitoring was also provided to confirm the suspected residue. Therefore, this analytical method was reproducible and sensitive enough to determine the residue of fomesafen in agricultural commodities.

• Korean Journal of Weed Science
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• v.10 no.2
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• pp.114-121
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• 1990

Inactivation in soil absorption, translocation of 2, 4-D by plants vary depending upon soil environments and herbicide formulations. Experiment was conducted in a glasshouse using rectangular pots($1350cm^2$) to evaluate the growth responses of barnyardgrass (Echinochloa crus-galli) and Indian jointvetch (Aesehyrcomene indica) to two formulations of 2, 4-D. The formulations used were 40% 2, 4-D amin salt (2, 4-D/AS) and 19.7% complex of rice husk lignin and 2, 4-D (2, 4-D/LG) which were applied at 200g ai/ha. Soil environments included fertilizer levels, soil pH, organic matter contents, and soil textures, Each treatment was replicated three times. The herbicidal activity of 2.4-D increased and lasted with increased levels of fertilizer. The activity also increased and lasted with low soil pH and decreased content of organic matter. Generally 2, 4-D/LG showed higher and longer herbicidal activity than 2. 4-D/AS for both test plants under all conditions applied. However, the herbicidal activity was influenced by the formulations more than by soil textures. It was thought that 2, 4-D/AS was released in a short time and inactivated readily while 2, 4-D/LG was slowly released and gave an opportunity of absorption by plants for a long period.

• The Korean Journal of Pesticide Science
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• v.9 no.1
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• pp.70-80
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• 2005

To evaluate the exposure of molinate in agricultural environment and its effect against the non-target crop in air, this experiment was conducted to elucidate volatilization characteristics of molinate in aquatic condition and to determine critical concentration of molinate in the air causing phytotoxicity to Chili pepper. Cumulative volatilized rate of molinate from water was 22.7% at $35^{\circ}C$ for water temperature and 20 L/min for air velocity while 3.2% at $25^{\circ}C$ and 10 L/min within 47 hour after applied under closed system, respectively. The molinate concentrations in air above 60 cm height from soil surface of valley and open paddy rice field were reached the highest value of 18.17 and $11.59{\mu}g/m^3$, respectively within 24 hours after applying granular formulation at dose rate of molinate 150 g/1,000 $m^2$. However, their concentrations were drastically diminished to around 0.18 and $0.51{\mu}g/m^3$ level in 20 days after application, which volatilization pattern were similar to both regions. Also, the concentration of molinate in air above 60 cm height from soil surface was distributed higher 2 times than that above 180 cm height. Meanwhile, a phytotoxic symptom against the nearby chili pepper was revealed within three days after applied and molinate was detected $0.004{\sim}0.006$ mg/kg level from severe damaged leaves. The dose and exposure relations of molinate in the air against the non-target crop was also investigated in lab trial. The phytotoxic symptom, shriveled leaves, of the chili pepper was encountered by exposing two days with concentration of $13.6{\mu}g/m^3$, three days with $6.8{\mu}g/m^3$ or four days with $3.4{\mu}g/m^3$. The symptom was still recovered within four weeks after the plants had received fresh air. On the other hand, the phytotoxic response through root uptake of the herbicide in water culture was relatively insensitive, in which the symptom is observed ten days with the concentration of 300 ${\mu}g/L$.

• The Korean Journal of Pesticide Science
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• v.7 no.3
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• pp.176-181
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• 2003

The leaching behaviour of [aniline-$^{14}C$]mefenacet in soil was investigated using glass columns (5 cm I.D. $\times$ 30 cm. H) packed with two types of soils with different physicochemical properties. $^{14}C$-Mefenacet (8.33 kBq) and mefenacet (in total, 1.05 mg/kg) were treated onto soil columns and rice plants (Oryza sativa L.) were grown for 17 weeks on these columns. Leachates from the columns were collected at the rate of 122.5 mL per week. $^{14}C$-Activities leached from soil A (OM, 3.1%; CEC, 86 mmol(+)/kg; texture, loam) columns with and without rice plants were 1.95 and 4.19% of the originally applied, whereas those from soil B (OM, 1.3%; CEC, 71 mmol(+)/kg; texture, loam) were 2.69 and 7.05%, respectively. These results indicated that larger amounts of $^{14}C$ were percolated from soil B with less organic matter and from the columns without vegetation. $^{14}C$-Activities absorbed by rice plants from soil A and B were 8.95 and 8.47%, respectively, most of which remained in the root and shoot excluding unhulled grains and ears without grains. $62\sim73%$ of the originally applied $^{14}C$ remained in the depth of $0\sim5cm$ in soil. The mass balance indicated that the losses by volatilization and/or mineralization amounted to $3.4\sim9.2%$ of the originally applied. $^{14}C$-Radioactivities in the aqueous phase of the leachates ranged from 59.4 to 97.7% of the radioactivities in leachates, showing the fast transformation of mefenacet to the polar metabolites.