• Korean Journal of Weed Science
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• v.16 no.3
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• pp.187-193
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• 1996

To supply seeds with a good quality as plant materials for herbicide screening and to know whether the germination characteristics could be associated with a differential response to herbicides, germination characteristics and differential responses to herbicides were investigated with 3 species of a genus Setaria ; Yellow foxtail(Setaria glauca P. Beauv, SETGL), Giant foxtail(Setaria faberi Hetrm, SETFA), and Green foxtail(Setaria viridis P. Beauv, SETVI). Degree of dormancy was high in the order of SETGL, SETVI and SETFA. The dormancy of SETGL seed was relatively well removed by room temperature and drying storage, but SETFA and SETVI by low temperature and wetting storage(stratification). For breaking dormancy of SETGL, SETVI and SETFA, it was necessary for being kept under the above storage conditions for at least 2, 4 and 4-5 months, respectively. When the dormancy-breaked seeds were transfered to low temperature($4^{\circ}C$) and drying condition, SETGL showed germination rate of 96% even after 2 month storage. However, SETVI and SETFA showed a decreased germination of 54% and 69%, respectively, with a decreased velocity of germination, indicating that secondary dormancy might be induced. On the other hand, a significant change in germination rate was not observed as the seeds were transfered to room temperature($25^{\circ}C$) and drying condition. The germinability of SETGL seed began to decline from 6th year after storage in room temperature and drying condition. All of 3 species showed relatively high germination rate at alternating temperature of $30^{\circ}C$/$20^{\circ}C$(14hr/10hr) and their germination were not increased by light. All of 3 species exhibited similar responses to cycloxydim, sethoxydim and primisulfuron in greenhouse experiment. In contrast, SETVI and SETFA were relatively susceptible to fenoxapropethyl, SETFA to fluazifop-butyl, SETGL and SETFA to clorimuron-ethyl, and SETGL to EK-2612. The difference in herbicidal response among 3 species was the highest in the treatment of EK-2612. These results suggest that there is no a consistent tendency in responses of 3 species to herbicides which have the same target site. And the relationship between germination characteristics and differential responses to herbicides was not found.

• Korean Journal of Weed Science
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• v.3 no.1
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• pp.75-99
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• 1983

The herbicidal properties of perfluidone [1,1,1-trifluoro-N-2-methyl-4-(phenylsulponyl) phenyl methanesulfonamide] were investigated in pots and paddy fields. At the rate of 2.0kg prod./10a, perfluidone did not cause any injury to the 4 leaf stage (LS) rice seedlings. Although the crop injury increased with increasing the application rate, the injury caused by 16kg prod. perfluidone/10a gave rise to only 30% yield reduction. The crop injury was greatest when perfluidone was applied 2 days before transplanting and decreased as the application time delayed. Perfluidone showed greater crop injury to the 3 LS seedlings, at more than 7cm water depth, and at high temperature than to the 4 LS seedlings, at 3-5cm water depth, and at low temperature. Indica and indica ${\times}$ japonica rice varieties were generally more sensitive to perfluidone than japonica rice variety. Perfluidone effectively controlled most of annual weeds and such perennial weeds as Sagittaria pygmaea MIQ., Potamogeton distinctus A. BENN, Cyperus serotinus ROTTB, Scirpus maritimus L., Eleocharis kuroguwai OHWL, and Scirpus hotarui OHWL, whereas Sagittaria trifolia L. and Polygonum hydropiper SPACH. were tolerent to perfluidone. The weeding effect decreased with increasing the leaching amount of water and the overflowing of irrigated water within 24 hours after the herbicide application. When the application time was done later than 8 days after transplanting, the perennial weeds were shown at deeper soil layers, and the standing water was deeper than 7cm, the effect tended to decrease. However, there was no difference in the weeding effect between soil types. Downward movement of perfluidone in flooded soil ranged from 2 to 8cm deep. The movement increased with increasing the leaching amount of water and the application rate and at a sandy loam soil which possessed less adsorptive capacity. Residual effect of perfluidone was found at 35 to 80 days after application, which varied such factors as Soil types. Increase in the leaching amount of water resulted in decrease in the period of the residual effect. The period was shorter at non-sterilized soil than at sterilized soil. The 0.75kg ai perfluidone + 1.5kg ai SL-49 (1,3-dimethyl-6-(2,4-dichlor-benzoyl)-5-phenacyloxy-pyrazole)/ha and 1.5kg ai perfluidone + 1.05kg ai bifenox (2,4-dichlorophenyl-3-methoxy carbonyl-4-nitro phenyl ether)/ha showed less crop injury than 1.5kg ai/ha perfluidone alone. However, the weeding effect of the former was similar to that of the later.

• The Korean Journal of Pesticide Science
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• v.2 no.3
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• pp.52-63
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• 1998

A novel quinolineoxadiazoles, substituted the carboxylic acid group with 1,2,4-oxadiazole radicle, of KSC-16960 and related compounds were evaluated to examine the herbicidal activity, crop injury and residual effect of after-vegetable crops compared with those of quinclorac (3,7-dichloro-8-quinolinecarboxylic acid), of which use is now banned because of its residual activity to some succeeding vegetable crops. KSC-16960 showed 2- and 3-leaf stages of barnyardgrasses effectively controlled by more than 95 and 90%, respectively, at a rate of 6.25 g/ha. The dose of KSC-16960 controlled 4- and 5-leaf stages of barnyardgrasses by more than 90% were found to be 50 g and 100 g/ha, respectively. The selectivity of KSC-16960 between direct-seeded rice and barnyardgrass was approximately 2-fold higher than that of quinclorac when they were treated to the soil. The selectivity indices of KSC-16960 and of quinclorac between 1-leaf stage of direct seeded rice and 5-leaf stage of barnyardgrass were 44 and 23, respectively, and those between 1-leaf stage of direct seeded rice and 4-leaf stage of barnyardgrass were almost 2-fold higher. Application of KSC-16960 with bentazone exhibited an additive controlling effect on several weed species, but that of quinclorac exhibited an antagonistic effect. With pyrazosulfuron-ethyl, on the other hand, both application of KSC-16960 and quinclorac showed additive interactions. Under a greenhouse condition, the residual activity of KSC-16960 to succeeding tomato plants was approximately 4-fold lower compared to that of quinclorac. KSC-16960 could be substituted for quinclorac, if it will be made some more improvement for reducing residual activity.

• Weed & Turfgrass Science
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• v.2 no.1
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• pp.1-7
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• 2013

Studies were carried out to provide basic information for establishing the weed control in Chungbuk, Korea. The present surveys targeting 260 farmers in Chungbuk province were conducted for the cultivation system, weeds occurrence and usage of herbicides. To estimate the occurring area of herbicide resistant weeds, soil samples from 400 paddy fields were collected twice on August, 2011 and April, 2012. In the results of survey, the 99.6% of farmers used the rice planting machine and the 78% of the farmers disseminated herbicides twice to control weeds before and after planting rice. The most commonly used herbicide were as follows; soil-applied herbicide : butachlor 46.6%, mid-term herbicide : mefenacet + pyrazosulfuron-ethyl 10.7%, foliar herbicides : bentazone 62%. The dominant paddy field weeds included Echinochloa crusgalli (16.2%), Scirpus juncoides (12.2%), Monochoria vaginalis (11.9%) and Sagittaria trifolia (9.5%). Occurrence area of sulfonylurea herbicide resistant weeds was 13,659 ha in 26.8% of the paddy area. Monochoria vaginalis showed the highest with 4,605 ha (36.4%) followed Scirpus juncoides (30.7%), and Lindernia dubia (10.6%) at 2011. Monochoria vaginalis and Scirpus juncoides occurred were evenly distributed and the most problematic weed in Chungbuk, Korea.

• Journal of Plant Biotechnology
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• v.35 no.4
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• pp.299-306
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• 2008

A modified method of Agrobacterium-mediated perilla transformation was developed using two selection markers of an antibiotics (either hpt or nptll) and an herbicidal (bar) gene. Perilla hypocotyl explants were cocultured with Agrobacterium tumefaciens EHA 105 strain harboring plasmid vector (either pMOG6-Bar or pCK-Bar) for three days, respectively. Primary shoots were selected with antibiotics of hygromycin (15 mg/L) or kanamycin (125 mg/L) and regenerated shoots were further selected with herbicide phosphinothricin (ppt,1.2 mg/L) to obtain authentic transformants. Roots were induced for the regenerated shoots on the MS medium without hormone and 80 putative transgenic plants were obtained. Transgene integration into perilla genome was confirmed by Southern blot and their expression was analyzed by Northern blot. T1 perilla seeds drived from To plants were tested 0.3% basta spray for identification of stable gene delivery to next generation.

• Korean Journal of Weed Science
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• v.11 no.1
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• pp.11-18
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• 1991

Seven formulations of oxyfluorfen selected from the previous studies(4. 5) were tesed to evaluate crop injury and herbicidal efficacy on two rice cultivars and several annual and perennial weeds in a greenhouse. Each formulation at two different rates was applied to rice transplanted with 8-, 22- and 32-day old seedlings and to direct-seeded rice. Among the formulations, Elvan, Bentonite B. Chitosan and Coal Slag gave lower injury than a control formulation, Sand-coated oxyluorfen, and they did not have a problem with excessive release if active ingredient at once. Especially, the formulations of Elvan, Chitosan and Bentonite B controlled annual weeds (Echinochloa crus-galli, Monochoria vaginalis, Cyperus difformis., and Scirpus juncoides) and perennial weeds (Sagittaria pygmaea, and Cyperus serotinus). The surface structure of the formulations indicate the different possibilities of releasing of oxyfluorfen by different cracking and hole sizes, namely retention capacity.

• Korean Journal of Weed Science
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• v.7 no.3
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• pp.321-328
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• 1987

In order to examine the factors affecting herbicidal injury of pepper, crop injury and growth response of 2 red pepper cultivars and 2 sweet pepper cultivars to napropamide and pendimethalin were evaluated under defferent conditions of soil texture, organic matter, soil temperature and seeding depth in the greenhouse. Growth response of 4 pepper cultivars was also examined by roos dipping to napropamide and pendimethalin. More inhibition of top leaf growth by root dipping to napropamide was occurred in red pepper cultivars than in sweet pepper cultivars. However, sweet pepper cultivars showed more severe inhibition of top leaf growth by root dipping to pendimethalin compared to red pepper cultivars. Crop injury due to napropamide and pendimethalin was more severe in sandy soil than in loam soil and this trend was more remarkably shown in sweet pepper cultivars. Crop injury due to napropamide and pendimethalin was reduced with the increase in organic matter especially in cv. Walgeykwan and cv. Orient al Pimento. As seeding depth of pepper cultivars became deeper, crop injury due to napropamide and pendimethalin was reduced in cv. Walgyekwan and cv. Oriental Pimento.

• Korean Journal of Weed Science
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• v.4 no.1
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• pp.11-18
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• 1984

The effect of transplanting method of rice seedlings on weed occurrence was investigated at the Yeongnam Crop Experiment Station in 1983. Rice was transplanted by hand and machine and eleven common herbicides were applied. The greatest weeds were harvested from the plot that rice was not transplanted and more weeds encountered at machine transplanted plot than hand transplanted plot. The degree of weed suppression by rice plant itself was 50% for machine transplatning and 55% for hand transplanting, respectively. Simpson index and community dominance of weed species were the highest in hand transplanting and followed by machine transplanting and no rice plot in order. Rice grain yield was exponentially correlated with the amounts of weed occurrence and more yield loss exhibited at machine transplanting than hand transplanting in the same amount of weeds. In the herbicidal activity, most of herbicides performed better at hand transplanting than machine transplanting while the degree of difference between transplanting methods varied depend on herbicide used.

• Korean Journal of Weed Science
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• v.31 no.2
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• pp.175-182
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• 2011

This study was conducted to evaluate the growth inhibition of weeds and selectivity of crop species by hairy vetch residues. The growth of all the weed species was suppressed greater than 90% at the ratio 60 : 40 of hairy vetch residues and no weeds were emerged at 90 : 10 mixture in the greenhouse. It was noticed that broadleaf weed species were more suppressed compared to grass weed species. Growth of weeds was significantly reduced and the inhibition percent was increased with increasing application depths of hairy vetch mixture both in vinylhouse and in field conditions. Among the different application depths of hairy vetch mixture, 0.75 cm depth of application tended to inhibit more, but statistically no significant difference was observed between 0.5 cm and 0.75 cm application depth. The growth of weed species such as Galium spurium, Chenopodium album, Plantago asiatica, and Rumex japonicus was greatly suppressed in the vinylhouse and the growth of G. spurium, R. japonicus and Amaranthus retroflexus was suppressed significantly in the field condition. The growth inhibition of all the above mentioned sensitive weed species was approximately 80% at the application depth of 0.5 cm. Crop growth was not hampered by using the residues of hairy vetch. This study demonstrated that rotation crop residues of hairy vetch contained high allelopathic potential to different weed species without hampering the growth of crop species.

• The Korean Journal of Pesticide Science
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• v.8 no.2
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• pp.79-87
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• 2004

3-Chloro-2-[4-chloro-2-fluoro-5-(5-methyl-3-phenyl-4,5-dihydroisoxazol-5-ylmethoxy)-phenyl]-4,5,6,7-tetrahy dro-2H-indazole(EK-5439) demonstrated rice selectivity and herbicidal activity on annual weeds, such as Echinochloa oryzicola, Monochoria vaginalis, Lindernia pyxidaria, Rotala indica, Aneilema keisak, Cyperus difformis, and Ludwigia prostrata at doses of 16-63 g a.i./ha. However, the application window was limited from pre-emergence to 5 days after transplanting. The control efficacy of EK-5439 on barnyardgrass was 4 times higher than that of oxadiazon. EK-5439 was excellently safe to the 16 different transplanted rice cultivars treated 2 days after transplanting. These compounds have the mechanism of action on the chlorophyll biosynthesis like protoporphyrinogen IX oxidase inhibitors.