• Weed & Turfgrass Science
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• v.7 no.3
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• pp.209-218
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• 2018

This study was carried out to investigate the occurrence and distribution of ALS inhibiting herbicide-resistant weeds and to estimate the appeared areas of resistant weeds in the paddy fields of Gyeongnam province of Korea in 2017 and 2018 using a soil assay method. Compared with the 2012 survey, this study showed that the infested ratio of ALS inhibiting herbicide-resistant weeds increased from 1.0% to 66.8% and the infested area increased from 876 ha to 49,008 ha. The infested area of ALS inhibiting herbicide-resistant weeds was estimated in Ulsan-si (8.4%), Hapcheon-gun (8.3%), Haman-gun (7.9%), Goseong-gun (7.9%), Hadong-gun (7.3%), Jinju-si (7.2%), Changnyeong-gun (7.0%), Gimhae-si (6.4%), Miryang-si (5.5%), Busan-si (4.9%), Uiryeong-gun (4.6%), Namhae-gun (4.3%), Geochang-gun (4.2%), Changwon-si (3.8%), Geoje-si (2.9%), Yangsan-si (1.8%), Sancheong-gun (0.9%) and Tongyeong-si (0.4%), and the herbicide resistant weeds was not occurred in Hamyang-gun. The most dominant ALS inhibiting herbicide-resistant weeds in paddy fields were Monochoria vaginalis, followed by Echinochloa oryzicola, Lindernia dubia, Scirpus juncoides, Ludwigia prostrata, Cyperus difformis, Sagittaria trifolia and Rotala indica. ALS inhibiting herbicide-resistant M. vaginalis, L. dubia, and E. oryzoides occurred throughout Gyeongnam province, and ALS inhibiting herbicide-resistant S. trifolia and R. indica were only found in Gimhae-si. Therefore, these results will be utilized to estimate population dynamics of ALS inhibiting herbicide-resistant weeds and provide proper management practices in the paddy fields of Gyeongnam province.

• Weed & Turfgrass Science
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• v.7 no.3
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• pp.181-190
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• 2018

This study was conducted to investigate the occurrence of an acetolactate synthase (ALS) inhibiting herbicide resistant weed on paddy at 289 sites by soil sampling in Chungcheongbuk-Do of Republic of Korea from February to April in 2017. The most dominant weed was Monochoria vaginalis and Echinochloa oryzicola on each city and county. ALS inhibiting herbicide resistant ratio and occurrence area were 80.6% and 28,272 ha, respectively, in Chungcheongbuk-Do which was 3 times than in 5 years ago. The herbicide resistant ratio, Okcheon-Gun was the highest at 93.8%, Chungju-Si, Boeun-Gun, Yeongdong-Gun, Jincheon-Gun and Geosan-Gun were over 80%, Cheongju-Si, Eumseong-Gun and Jeungpyeong-Gun were over 70%. The herbicide resistant area, Cheongju-Si had the largest at 6,957 ha, Chungju-Si was 4,277 ha, Jincheon-Gun and Boeun-Gun was 3,536 ha and 3,282 ha, respectively. By weed, ALS inhibiting herbicide resistant ratio and occurrence area, Monochoria vaginalis was 49%, 17,646 ha, Echinochloa oryzicola 44%, 15,617 ha, Schoenoplectiella juncoides 29%, 10,377 ha, respectively. In all cities and counties of Chungcheongbuk-Do, Monochoria vaginalis and Echinochloa oryzicola are more than 40% resistant to ALS inhibiting herbicides, intensive management is required. The use of sulfonylurea herbicides is increasing, most farmers use herbicides 10 days after transplanting, so management after transplanting is necessary and the occurrence of herbicide resistant weeds should be reduced by alternating herbicide application every year.

• Korean Journal of Weed Science
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• v.32 no.2
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• pp.121-126
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• 2012

National Academy of Agricultural Science and eight province Agricultural Research & Extension Services investigated the occurring area of herbicide resistant weeds in paddy field of Korea. In order to estimate the occurring areas of herbicide resistant weeds, we collected paddy soils on August, 2011 and treated 30kg $ha^{-1}$ of pyrazosulfuron-ethyl+pyriminobac-methyl GR. 167,081ha, approximately 20.9% of cultivated area excluding organic and eco-friendly cultivated area, was estimated to be infested by SU-herbicide resistant paddy field weeds. It was increased by 60,130ha compared with investigation of 2008. It was occurred at Chungchungnam-do by 47.6%, followed by 36.9% at Jeonranam-do, 25.7% at Chungchungbuk-do, 20.5% at Gangwon do, and 13.0% at Gyeonggi-do, respectively. Monochoria vaginalis showed the highest with 65,313ha, 39.1% followed by Scirpus juncoides, and Cyperus difformis, respectively. These three species were evenly distributed and the most problematic weeds in the country. Lindernia dubia occurred at 13,964ha (8.4%) and Echinochloa oryzicola was 5.1%, respectively.

• Weed & Turfgrass Science
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• v.3 no.2
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• pp.71-77
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• 2014

Surveys of weed species in paddy fields were conducted in Korea to identify weed occurrence from June to September 2013. Total 3,434 sites of paddy fields in 155 City/Gun, eight Provinces were investigated. From the nation-wide survey, 90 weed species in 28 families were identified and classified to 52 annuals, 3 biennials and 35 perennials. Based on the occurrence ratio, the most weed species belonged to Poaceae (18 species). 17, 8 and 6 weed species belonged to Cyperaceae, Scrophulariaceae and Polygonaceae, respectively, and these 49 weed species in the most four families accounted for 54% of total weed occurrence. The most dominant weed species in Korean paddy fields were Echinochloa spp. (17.4%), followed by Monochoria vaginalis (12.4%), Eleocharis kuroguwai (7.8%), Bidens tripartite (9.27%), Scirpus juncoides (6.2%) and Sagittaria sagittifolia (6.1%). This information could be useful for estimation of future weed occurrence, weed population dynamics and establishment of weed control methods in paddy fields of Korea.

• Korean Journal of Weed Science
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• v.10 no.4
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• pp.269-276
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• 1990

Weed species belonging to the broadleaf family prevailed in the experimental sites followed by Cyperucea and grass family. In terms of life cycle, the dominant weed species were the perennial weeds rather than annual weeds. Most of weeds were emerged between 30-60days after transplanting in Chuncheon and between 40-60 days after transplanting in Hongcheon and Hoengseong areas. Among agronomic characteristics of rice affected by weed emergence were decrease of plant height by 2-4㎝, panicle number by 1.3-2.9, spkelet by 3. 7-7.5, ripening rates by 3.3-6.5%, and milled yield by 12-17%.

• Korean Journal of Weed Science
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• v.3 no.2
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• pp.174-189
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• 1983

Experiments were conducted to evaluate the herbicidal characteristics of pyrazolate [4-(2,4-dichloro benzoyl)-1,3-dimethylpyrazol-5-yl-p-toluene-sulphonate] in greenhouse and lowland rice field. Pyrazolate controlled effectively most of annual weeds and such perennial weeds as Sagittaria pygmaea MIQ., Potamogeton distinctus A. BENN, Sagittaria trifolia L., Cyperus serotinus ROTTB, and Scirpus hotarui OHWI., whereas Eleocharis kuroguwai OHWI. was tolerent to pyrazolate. Although pyrazolate was applied at 2 to 10 days after transplanting, there was no difference in weed control The weeding effect was not influenced by percolation, depth of water and soil type. No difference in crop injury of rice was found with various levels of seedling age, transplanting depth, percolation, depth of water, soil type and time of application. When combined with butachlor, the mixture gave the same effect on rice phytotoxicity and weed control as pyrazolate alone did. Pyrazolate moved 1 to 2cm downward in lowland soil regardless of soil type and percolation. The herbicidal activity of pyrazolate persisted in soil for 60 to 90 days, depending on soil type, percolation and presence of soil microorganism.

• Korean Journal of Weed Science
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• v.14 no.3
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• pp.163-170
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• 1994

The experiment was conducted in 1993 to find out a simple prediction method of weeds and to make the prediction models of weeds in paddy fields. The annuals producing fine seeds were apt to emerge at sampling soil only, on the contrary the perennials and the annuals producing large seeds tended not to emerge at sampling soil due to the miss of seeds at sampling. There was no appropriate regression between a total number of weeds emerged at sampling soil and that of weeds occurred in fields. The important annual weeds occurring in fields were able to predict by the number of weeds emerged at sampling soil, but it was difficult to predict the important perennial weeds. In case of Bidens tripartita producing large seeds and Eleocharis kuroguwai producing large tubers, the prediction coefficients were high as above 1.0, and that of Echinochloa crus-galli and Sagittaria pygmaea were comparatively high as 0.175 and 0.172, respectively. However the coefficients of the other weeds were much low as below 0.08. The prediction models for 9 species were made. The model of six species including E. crus-galli, M. vaginalis, R. indica, B. tripartita, E. triandra and S. pygmaea were linear regression with high significance, however that of 3 species including C. difformis, S. juncoides and E. kuroguwai were curve regression with high significance.

• Journal of the Korean Institute of Landscape Architecture
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• v.51 no.3
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• pp.1-20
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• 2023

The present study has monitored the changes in the biodiversity of Dunchon-Dong ecological and landscape conservation area after the restoration of the wetland, identified and analyzed the threats to the ecosystem, and presented a management plan accordingly. In this area which was forests and rice paddies in the past, apartment reconstruction is currently underway, with some hinterland forests and wetlands remaining. When we look into the change in the floras, the total number of species was 193 in 2000 before the restoration, it decreased from 2004 to 2006, and as of 2019, it was 149, showing an increasing trend. The result of comparing the species that emerged before and after the restoration showed an increase in Cyperaceae herbs such as Carex maximowiczii and Carex dispalata growing in wetland areas within forests and Schoenoplectiella juncoides and Schoenoplectus tabernaemontani growing in areas within wetlands where shallow water is maintained. As a result of analyzing the change in the area ratio of each type of extant vegetation, the wetland native herbs formed the power at the highest ratio after the restoration. The change in the power of the wetland native herbs was on an increasing trend until 2007, after which it decreased much in 2010 and then gradually increased, showing values of 26.6% in 2000, 44.6% in 2002, 49.0% in 2005, 53.3% in 2007, 28.7% in 2010, and 37.3% in 2019. The cause of the decrease in 2010 was judged to be due to the vegetation management conducted to secure open water and remove organic matter in freshwater reservoirs. The amphibia which emerged from 2000 to 2019 was a total of 9 species including Hynobius leeshii, Bufo gargarizans, Kaloula borealis, and Rana uenoi. As a result of the changes in the emerging wild birds, the species diversity index before the restoration was 0.9922 in 2000, and the species diversity index after the restoration gradually increased to 1.2449 in 2005, 1.2467 in 2010, and 2.2631 in 2019. The amphibia and wild birds inhibiting in the Dunchon-Dong forest and wetland were judged to have increased through continuous wetland maintenance such as naturalized plant removal management, native plant maintenance, and open water securing management. For the ecosystem preservation management of the Dunchon-Dong ecological and landscape conservation area, it was suggested to minimize the impact of the Dunchon-Dong reconstruction project, reorganize the indiscriminate access roads adjacent to the wetland, and reorganize the main entrance to the wetland. For ecosystem restoration management, systematic restoration and ecological buffer planting were suggested to be carried out at the time of construction fence demolition.

• Applied Biological Chemistry
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• v.39 no.4
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• pp.297-303
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• 1996

A series of the herbicidal N-(4,6-disubstituted pyrimidin-2-yl)aminocarbonyl-2-(1,1-ethylenedioxy-2-fluoro)ethyIbenzenesulfonamides, 1 and N-(4,6-disubstituted triazin-2-yl)aminocarbonyl-2-(1,1-ethylenodioxy-2-flu ore)ethylbenzenosuIfonamides, 2 were synthesized and their herbicidal activities in-vivo against rice(Oryza sativa L.), barnyard grass (Echinochloa crus-galli), bulrush(Scripus juncoides) and pickerel weed(Monochoria vaginalis presl.) were measured by the pot test under the paddy conditions. The structure activity relationships(SAR) between the herbicidal activity$(pI_{50})$ and a various physicochemical parameters of the hetero group and 4,6-disubstituents on the heterocyclic group were analyzed by the multiple regression technique. The SAR suggest that the 4,6-dimethoxypyrimidine substituent, 1a showed selective$({\Delta}obs.pI_{50}=1.12)$ and the most highest activity against barnyard grass, which depend on the hydrophobicity(log P<0) of heterocyclo group and molecular refractivity$((M_R)_{opt.}=14.58cm^3/mol)$ constant of 4,6-disubstituents on the heterocyclic group.

• 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.