• Korean Journal of Weed Science
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• v.18 no.1
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• pp.28-35
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• 1998

Cyhalofop/bentazon ME and pyribenzoxim EC herbicides were originally developed as foliarapplied herbicides to control weeds at 4-5 leaf stages of barnyard grass 20-25 days after seeding (DAS) in direct-seeding culture but further possible utilization of these two herbicides earlier than 3-4 leaf stages of rice were evaluated for a field where early weed infestations might be severe. The application of cyhalofop/bentazon ME and pyribenzoxim EC at right after rice emergence and the 2-3 leaf stages of rice had an excellent weed control efficacy with above 90% up to 30 DAS without a phytotoxicity of rice plant and the control efficacy of over 80% was maintained until 60 DAS. However, these two herbicides controlled Echinochloa crus-galli very effectively above 97% but Aneilema keisak and Aeschynomene indica were not controlled by cyhalofop/bentazon ME and Cyperus serotinus by pyribenzoxim EC. Therefore, to control those problem weeds, second systematic application of pyribenzoxim EC and pyrazosulfuron/mefenacet G for A. keisak and A. indica, and pyrazosulfuron/molinate G, cyhalofap/ azimsulfuron/molinate G, pyrazosulfuron/mefenacet G and bentazon SL for C. serotinus at 30 DAS was found to be very efficient herbicide systems.

• Korean Journal of Weed Science
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• v.18 no.1
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• pp.12-19
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• 1998

The pattern of rice cultivation in Korea is changing from hand transplanting and machine transplanting into direct-seeding for low input and cost-down practices. However, there are still some obstacles to establish the direct-seeding cultural practices because of poor seedling stand, lodging, and weed infestation. In particular, there were much more and wide weed occurrence in direct-seeding rice as compared with the transplanted rice. Weed occurrence in terms of dry weight of weeds was highest in dry direct-seeded rice followed by sowing an puddled soil, sowing on submerged soil in order as compared with transplanting with infant rice seedling. Echinochloa crux-galli was a common dominant weed with 35~44% distribution in any direct-seeding methods. The dominant weed species were E. crux-galli, Cyperus difformis, C. serotinus, and Ludwigia prostrata in dry-seeded rice. The dominant weed species in water-seeded rice were E. crus-galli, Eleocharis kuroguwai, Scirpus juncoides, and Monochoria vaginalis. Yield loss of rice due to weeds at weedy condition was 96% in dry direct-seeded rice. In water-seeded rice, yield loss was 61%, whereas yield loss was 40% in machine transplanting with infant rice seedling.

• Korean Journal of Environment and Ecology
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• v.28 no.6
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• pp.705-714
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• 2014

This text was analyzed and investigated the aerial part plants and buried seed plants at coniferous forest and broadleaved forest in Yesan-gun, in order to offer the basic data of potential natural vegetation change on secondary forest. Plants of buried seed germination were consisted of 29 taxa in coniferous forest (28 species, 1 varieties, of 27 genus, 20 families) and 36 taxa in broadleaved forest (34 species, 2 varieties, of 32 genus, 18 families). Family classification of buried seed plant was the most in Compositae, and emergent plot frequency was the highest of Cyperus amuricus in coniferous forest and Crepidiastrum sonchifolium in broadleaved forest. The soil depth of the most plants appearance was 0~10 cm in coniferous forest and 0~5 cm in broadleaved forest, and the soil depth of the most population appearance was 0~2 cm in coniferous forest and broadleaved forest. Population of buried seed germination was decreased according as soil is deep. Crepidiastrum sonchifolium was a plant that population of buried seed germination is the most. Similarity index of the aerial part plants and buried seed plants was low as 0.22, and coniferous forest and broadleaved forest was 0.40.

• Korean Journal of Food Science and Technology
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• v.29 no.6
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• pp.1288-1294
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• 1997

For screening antimutagenic effects, the effects of 95 medicinal plants on the mutagenicity of aflatoxin $B_1$ $(AFB_1)$ and benzo(a)pyrene [B(a)P] were investigated using the SOS chromotest with Escherichia coli PQ37. The mutagenicity induced by $AFB_1$ or B(a)P was reduced over 26% by 2 kinds and 8 kinds of medicinal plant, respectively. Eight plants (Bupleurum falcatum, Corydalis ternata, Gasfrodia elata, Ostericum koreanum, Pinellia ternatia, Poncirus trifoliata, Prunus armeniaca and Rehmannia glutinosa) were also shown to have inhibitory effects on both $AFB_1$ and B(a)P. The mutagenicity induced by $AFB_1$ or B(a)P was increased over 20% by 46 kinds and 2 kinds, respectively, and 8 medicinal plants (Chrysanthemum indicum, Cinnamomum cassia, Cyperus rotundus, Morus bombycis, Patrinia scabiosaefolia, Petasites japonicus, Polygonum multiflorium, Thyja orientalis) increased significantly the mutagenicity of both mutagens. However the 8 plants themself did not show the mutagenicity in SOS Chromotest with S-9 mix alone. This result suggests that the above 8 plants may have the co-mutagenic activities. In two bacterial mutation system, SOS Chromotest and Ames test, the mutagenic or antimutagenic activities of some medicinal plants wire similar except Ostricum koreanum, Eugenia caryophyllata and Scutellaria baicalensis.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.4
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• pp.287-292
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• 1981

The field studies were carried out in paddy field over a four year period in order to find out the effects of butachlor, nitrofen, oxadiazon or CG 102, benthiocarb-S, and bentazon applied successively to the same paddy field for four years on weed succession and rice yields under different fertilized conditions including compost, chemical fertilizer and straw application. Total dry weight of weeds was steadily increased yearly over 4 year period regardless of fertilized conditions, and significantly higher increase of weed dry weight was observed on non-fertilized and compost plots. The most dominant weed species was Scirpus hotarui, and Potamogeton distinctus, Eleocharis kuroguwai and Cyperus serotinus were predominated on compost plot, E. kuroguwai and E. aclularis on non-fertilized plot, E. kuroguwai, C. serotinus, and Monochoria vaginalis on chemical fertifizer plot, and C. serotinus on straw plot. When the same herbicides were used continuously on the same plots, weed control effect was decreased and thus weed population was greatly increased particularly on butachlor and nitrofen treated plots. P. distinctus, E. kuroguwai, and C. serotinus were predominated on butachlor treated plot, P. distinctus and C. serotinus on nitrofen treated plot, C. serotinus on benthiocarb-S treated plot, C. serotinus and P. distinctus on oxadiazon or CG 102 treated plot and P. distinctus on bentazon treated plot. Annual weeds were slightly increased by repeated annual application of oxadiazon or CG 102 and benthiocarb-S, whereas perennial weeds were predominated by successive application of butachlor, nitrofen. and bentazon for 4 years. Yield reduction of rice became prominent by successive application of same herbicides. particularly butachlor and nitrafen. This results suggested that successive annual application of same herbicides should be limited and herbicide combination or herbicide rotation should be applied to control the remaining weed species.

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

In order to get basic information for establishing weed control methods, weed distribution was surveyed at 15 days interval in garlic and red pepper fields at 8 locations in Chungnam Province. In garlic fields, 68 weed species(27 families) were distributed. Portulaca oleracea, Chenopodium album and Digitana sanguinalis were most dominant and Equisetum arvense, Alopecurus aequalis, and Setaria viridis dominant among them. Highest number of weeds emerged in May and dry weight or weeds was more heavy in June and summer broadleaf weeds were most abundant throughout garlic growing period. In red pepper fields, 38 weed species(17 families) were distributed, D. sanguinalis, Cyperus amuricus and P. oleracea were most dominant and Echinochloa crus-galli, Eleusine indica, D. violascens, and Centipeda minima also dominant among them. The highest number of weeds were emerged in June and summer, grasses and summer broadleaf weeds were more abundant in June and July. Seasonal Shannon's diversity index(H'), maximum diversity(Hmax') and eveness(J') for the Shannon diversity index, and Simpson index were high in both red pepper and garlic fields. Interspecific competition(probability for interspecific encounter) was more severe than intraspecific competiton.

• Korean Journal of Weed Science
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• v.7 no.2
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• pp.139-143
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• 1987

This experiment was conducted to investigate the effect of herbicide on the photosynthetic activity of the weed and rice plant. Two rice cultivars "Nongbaeg" and "Taebaegbyeo" were tested with butachlor, Molis-M, and perfluidone at 5 days after transplanting. Bentazone and propanil were sprayed at 25 days after transplanting. Photosynthetic activity was varied with herbicide and varieties. Generally, application of herbicide resulted in decreased photosynthetic activity. Indica ${\times}$ Japonica variety showed more sensitive to herbicide than Japonica variety. Recovery of the photosynthetic activity was faster in the bentazon than the propanil.

• Korean Journal of Weed Science
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• v.18 no.2
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• pp.154-160
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• 1998

This study was conducted to develop a foliar applied herbicide mixture covering wide spectrum weeds in dry direct seeded rice. Uniform precision central composite design(UPCCD) was employed to evaluate the effect of herbicide mixture among cyhalofop-butyl(cyhalofop), bispyribenzoxim and pyrazosulfuron-ethyl(pyrazosulfuron) having different weed control spectrum and to determine the best application rates of the three herbicide mixtures. The partial additive effect was observed in the mixture of cyhalofop and bispyribenzoxim with pyrazosulfron against Echinochloa crus-galli Beauv var crus-galli L., attributed to the negative interaction between cyhalofop and bispyribenzoxim system. Additive effect was observed in the mixture of bispyribenzoxim and pyrazosulfuron against Cyperus serotinus R. and Aneilema keisak H. but cyhalofop had no effect on these weeds. The most appropriate rate of the mixture of cyhalofop with bispyribenzoxim and pyrazosulfuron was 100 : 12 : 10g ai/ha exhibiting $ED_{90}$ against three weeds such as E. crus-galli, C. serotinus and A. keisak.

• Korean Journal of Weed Science
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• v.13 no.1
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• pp.26-35
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• 1993

Differences in weed occurrence was investigated among five types of rice (Oryza sativa L.) cultivation. The five types employed were three transplanting cultivations such as conventional hand transplanting, machine transplanting with 30-day-old seedling, and machine transplanting with 10-day-old seedling and two direct-seedings such as flood direct-seeded rice by pregerminated seed and dry direct-seeded rice by dry seed. Weed specie, occurred varied from 7 to 20, depending on the different cultivation types. Weeds were more diverse in transplanting with l0-day-old seedling than in other transplanting cultivations and in direct-seeding than in transplanting practice. Dominant weed species also varied with cultivation types. In transplanting cultivations Scirpus juncoides Roxb., Echinochloa crus-galli (L.) P. Beauv., and Eleocharis kuroguwai Ohwi were dominant, whereas occurrence of annual weeds such as Cyperus difformis L. and Monochoria vaginalis Presl. aside from the three weed species increased in direct-seeded cultivations.

• Weed & Turfgrass Science
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• v.2 no.2
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• pp.111-121
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• 2013

Literatures were reviewed to understand the weeds occurring on the lawn and the effective control methods of them. Thirty-seven species of 16 families including three species of Cyperaceae for example Cyperus sanguinolentus, nine species of Poaceae including Digitalis ciliaris, Poa repens, etc., and 25 species of broad-leaved weeds such as Artemisia princeps, Draba nemorosa, Hydrocotyle sibthorpioides were occurred on the lawns. One hundred ninety-six weed species of 53 families were occurred on a tomb graveyard adjacent to the mountain. Therefore, it is possible to be infested by the weeds occurring on the graveyard on the golf course adjacent to the mountains. There are 67 items, 32 kinds of the soil treatment herbicides including dichlobenil GR, methiozolin EC, oxaziclomefone SC, imaxaquin GR et al, and 35 kinds of the foliar treatment herbicides including metamifop EC, bifenox flucetosulfuron WG, flazasulfuron WP, trifloxysulfuron-sodium WG et al. registered at the end of May 2012 for efficient management of the weeds occurring on the lawn. For effective management of the weeds, the herbicide can be generally applied twice a year on March to April and August to September for soil treatment and once a year on June to July for the foliage treatment.