• Korean Journal of Weed Science
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• v.17 no.4
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• pp.407-412
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• 1997

Allelopathic activity of methanol extract from medicinal plants was determined based on the inhibition of germination, shoot and root length of Echinochloa crus-galli. The response was depended on the source of extracts and concentrations. Of the 20 test plants tested, Cnidium officinale showed most inhibition according to germination, shoot and root length of E. crus-galli. Based on the plant parts, the root extract of C. officinale had more inhibitory effect on E. crus-galli than the stem+leaf extract. Phytotoxic effects of the root extract on E. crus-galli showed 75% inhibition of seed germination, 95% inhibition of shoot growth, and 100% inhibition of root growth at the concentration of 1g/petridish. Sequential partitioning of root extract with organic solvents with increasing polarity showed that the ethylacetate fraction had the greatest inhibitory effect on E. crus-galli. Germination was not inhibited at any rate of ethylacetate fraction but shoot and root growth, were significantly inhibited even at 2mg/petridish. This indicates that the most toxic phytotoxin present in the root extract may be moderate polar compound.

• Korean Journal of Weed Science
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• v.7 no.2
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• pp.179-185
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• 1987

Laboratory studies were conducted to evaluate safening effect of CGA 123'407 (4,6-dichloro-2-phenyl-pyrimidine) against pretilachlor, butachlor, and benthiocarb in rice plants. Butachlor and benthiocarb at 50 ppm or higher concentrations significantly inhibited rice growth and pretilachlor gradually inhibited growth of rice plants with increase in concentration starting from 0.5 ppm. CGA 123'407 at 0.1 ppm or higher concentrations was effective in reducing injury of rice plants when butachlor and benthiocarb were applied at rate of 10 ppm. Rice injury from pretilachlor at 10 ppm was also reduced by addition of CGA 123'407 at 0.25 ppm or higher concentrations Herbicidal activity of pretilachlor, butachlor, and benthiocarb was not affected by mixture treatments of CGA 123'407.

• Korean Journal of Weed Science
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• v.8 no.1
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• pp.59-63
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• 1988

In order to select herbicides which may feasible to water-seeded rice culture, pot trial was initiated to determine phytotoxicity of rice plants to pyrazolate, bensulfuron methyl, chlormethoxynil, and benthiocarb under water-seeded condition. Pyraolate at 300 and 600 g ai/10a did not show crop injury and growth inhibition of rice plants. Bensulfuron methyl at 5.1 g ai/10a and benthiocarb at 210 g ai/10a were relatively safe to water-seeded rice plants when treated at 5 days after seeding. Chlormethoxynil at 210 g ai/10a showed crop injury and growth inhibition of rice plants and thus may not feasible to water-seeded rice culture.

• Weed & Turfgrass Science
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• v.3 no.3
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• pp.206-214
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• 2014

Numerous cases have been reported of naturalization by exotic ornamental plants. To obtain basic data about how those plants affect the ecosystems of Korea, we compiled a list of 78 species categorized as ornamentals from 309 naturalized species in Korea and analyzed their life forms, origin, and their current global status of naturalization and regulation. Plants belonging to Compositae comprised the largest group, with 23 species. In all, 75 species were considered herbaceous, and perennial species out-numbered annuals and biennials. Most species originated from Europe and North America. Except for Houttuynia cordata, the other 77 species were naturalized in other countries as well. Furthermore, 34 species, including Aster pilosus and Solidago altissima, have been subject to legal restrictions or classified as alert species in Korea or other countries. Therefore, monitoring may be required to prevent spread of those species, especially for species which have not been managed under domestic law up to now.

• Korean Journal of Weed Science
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• v.30 no.3
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• pp.272-281
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• 2010

The objective of this research was to find out the weed management techniques in environment-friendly rice paddy fields through the study on herbicidal effects and problems of various organic materials. This experiment was conducted under different conditions of weed species and weed densities in environment-friendly rice paddy fields. There was no difference in weedy efficacy on golden apple snail (GAS), paper mulching (PM), and machine weeding (MW) between low and high weed densities. However, the effect of weed control in rice bran (RB) and effective microorganism (EM) + molasses was higher in high weed density than in low weed density. In general, the effect of weed control as affected by various organic materials was in the order of GAS (97-100%) > PM (93-98%) > RB (15-80%) > EM (7-31%). GAS provided excellent control of all weed species tested except for Persicaria hydropiper. PM gave acceptable control of the weed species except for Echinochloa crus-galli, Ludwigia prostrata, and Eleocharis kuroguwai. However, MW gave fair control (70% biomass reduction) of all weed species tested. BR followed by MW or EM followed by MW treatments had similar effect on weed control compared to each treatment alone. However, BR followed by GAS or EM followed by GAS provided 100% control of weed species tested. The level of rice foliar injury caused by various organic materials was in the order of GAS and MW (10-20%) > RB (10-15%) > PM and EM (5-7%). Typical symptoms of organic materials are wilting, inhibition of growth, missing hill, and reduction of tiller. Cost for weed control of GAS, RB, EM, and PM were 2.1, 3.1, 2.3, and 13.2 times higher than that of the herbicide. These data indicate that GAS was the best method for weed management in environmentfriendly rice paddy fields. Further study is required to elucidate the mechanisms underlying the rice injury as affected by GAS.

• Weed & Turfgrass Science
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• v.3 no.4
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• pp.269-275
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• 2014

A survey was conducted to identify the occurrence of problematic weed species on the Dioscorea oppostifolia fields in South Korea. Total 43 sites of the 8 different regions in S. Korea were investigated from May to October, 2014. In yam fields, the identified weeds were distributed in 11 families and 44 species. The exotic plants were identified as 3 families, 10 genera, 10 species. The vegetation of Dioscorea oppostifolia fields was classified into communities of 7 groups by methods of the Zurich-Montpellier school of phytosociology (Xanthium canadense Community, Bidens frondosa Community, Echinochloa oryzoides Community, Eclipta prostrata Community, Portulaca oleracea Community, Centipeda minima Community, Rorippa islandica Community). The weeds occurred in Dioscorea oppostifolia fields were divided into three groups in principal component plot analysis (PCA). Without weed control, yields loss in yam production was reached up to 82% as compared to weed controlled fields.

• Weed & Turfgrass Science
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• v.4 no.1
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• pp.65-70
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• 2015

We have found the plants belonging to the genus Spartina which has not yet been reported for the flora of Korea. This has been distributed at Dongmak seashore in Ganghwado since 2012. These were identified as common cordgrass (Spartina anglica C. E. Hubb.) belonging to the family Poaceae, the genus Spartina. It is a perennial halophyte as an alien weed that can grow in the tidal flat, native to southern England. Here, we named it for 'Young-guk-Gaet-ggeun-pool' in Korean refer the origin, reported the distribution, spreading condition, and botanical characteristics of common cordgrass. In China, Spartina anglica was introduced in 1963, it was approved that it had benefit in a bioengineering side firstly. But it was known that as a highly invasive plant to make a monotype meadow of Spartina anglica which has deteriorate the ecological function of saltmarsh. And also it has another problem that is not easy to eradicate. The spreading of Spartina anglica which was appeared in the West coast of Korea may threaten severely to the domestic mudflat and estuary ecosystem. For the maintenance of mudflat ecosystem soundly, continuous monitoring and active eradication plans are required.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.1
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• pp.79-84
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• 1991

The rice plants (Oryza sativa L.) established from the shattered grains by combine harvesting at the previous year showed great variations of yield and yield components from site to site at the abandoned rice crop field. The cultural condition was very similar to direct seeding under no-tillage system but no cultural practices such as application of fertilizer, weed control, irrigation and drainage had been carried out. The highest yield of 188kg/10a was observed at one of the quadrats randomly located on the field, which showed the possibility of exploitation of no-tillage system. The interrelationship between crop growth and coverage of weed species was measured by calculating the correlation coefficients. The investigations of how to establish sufficient number of seedlings per unit area, plant succession on the abandoned crop field, crop mixture with legume crops, and breeding appropriate plant type of rice for the enhancement of competitive ability would be required for the success of no-tillage system.

• Weed & Turfgrass Science
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• v.4 no.4
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• pp.321-329
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• 2015

The present study aimed to evaluate the phytotoxic potential of essential oils. For this purpose, 18 essential oil samples extracted from Korean plants and 64 commercial essential oils were screened for their phytotoxic potential against the seedling growth of Brassica napus L. (rapeseed). Among the 82 samples, 11 commercial oils (cinnamon, citronella, clove, cumin seed, geranium, jasmine, lemongrass, palmarosa, pimento, rose otto and spearmint) strongly inhibited the seedling growth with $GR_{50}$ value < $150{\mu}g\;mL^{-1}$. Major components from these effective essential oils were identified by solid phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS). GC-MS analyses revealed that the effective samples mainly consist of benzyl benzoate, carvone, citral, citronellol, eugenol, geraniol, D-limonene and terpinene. Subsequently, bioactivity of these individual components was evaluated against the seedling growth of B. napus, Echinochloa crus-galli and Aeschynomene indica. The components from different chemical groups exhibited different potency in inhibiting the seedling growth with varied $GR_{50}$ values ranged from $29{\mu}g\;mL^{-1}$ to > $1000{\mu}g\;mL^{-1}$. In the greenhouse experiment, citral and geraniol completely suppressed the growth of all the tested 10 plants at $100kg\;ha^{-1}$. In conclusion, the individual essential oil components geraniol and citral could be used as natural herbicides for weed management.

• Korean Journal of Plant Resources
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• v.32 no.5
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• pp.543-558
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• 2019

This study was carried out to apply the taxonomic characters to identify and to provide the habitat circumstances for forty one un-introduced environmentally harmful plants in the Korea which have been designated by Ministry of Environment in 2016. We investigated the dried plant specimen from several herbaria and performed field habitat survey in western coast area of United States including California, Oregon and Washington. We suggest the first result for ecological risk discussion, weed risk assessment, taxonomic characters and classification keys for 8 species with the related species - Carduus acanthoides L. (Asteraceae), Carduus tenuiflorus W. Curtis (Asteraceae), Onopordum acanthium L. (Asteraceae), Chromolaena odorata (L.) R.M. King & H. Rob. (Asteraceae), Hydrocotyle ranunculoides L.f. (Apiaceae), Oenanthe pimpinelloides L. (Apiaceae), Ehrharta erecta Lam. (Poaceae), and Paspalum conjugatum P.J. Bergius (Poaceae).