• 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.16 no.1
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• pp.14-20
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• 1996

Growth, nutrient uptake and photosynthesis as affected by submersion of shoot in pickerel weed (Monochoria vaginalis Presl.) were determined. The shoots of pickerel weeds in hydroponic culture were subjected to the submerged or emerged condition at 3- or 5-leaf stage for 8 or 10 days. Under submerged condition, growth in plant height was enhanced, but leaf number, leaf area, fresh and dry weight were reduced compared to those under the emerged condition. Similar responses in growth to submergence were obtained with the pickerel weeds rooted in the soil. Under submergence, chlorophyll content increased during the first 2 days, but thereafter remarkably decreased at 3-leaf stage and after the first 4 days at 5-leaf stage. Compared to the emerged condition, uptakes of $NH_4\;^+$-N, $NO_3\;^-$-N, $P_2O_5$ and $K^+$ were reduced, but uptakes of $Ca^{++}$ and $Mg^{++}$ increased under the submerged condition. Photosynthetic rate of shoot under water, measured by $CO_2$electrode, showed the maximum by 210 ${\mu}$moles $HCO_3\;^-$/g F.W. at the 8th day after submergence(DAS) at 3-leaf stage and 320 ${\mu}$moles $HCO_3\;^-$/g F. W. at 6 DAS at 5-leaf stage. These results indicate that pickerel weeds grow much better when the shoot is air-exposed and are less tolerable to submergence at 3 leaf-stage than at 5-leaf stage.

• Weed & Turfgrass Science
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• v.3 no.4
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• pp.312-317
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• 2014

This study was conducted to obtain basis information for effective weed control by the fact-finding survey of herbicides use at farmer's level and distribution of herbicide resistant weeds in paddy field of Jeonbuk province, Korea. The distributions of major paddy field weeds and frequently used herbicide according to the survey were as follows. The dominant weeds in rice paddy field were Echinochloa crus-galli, Eleocharis kuroguwai, Scirpus juncoides, Monochoria vaginalis, etc.. Preferred herbicides widely used by farmers were ranked in the following order, early and middle treatment (48.0%), treatment before transplanting (36.7%) and foliar treatment (15.3%). The occurrence of herbicide-resistant weeds according to collected paddy soils was as follows. The occurring area of herbicide-resistant weeds was 24,413 ha, approximately 18.4% of rice cultivation area. Herbicide-resistant weeds were occurred in four species. The order of occurrence were Scirpus juncoides (39.0%) > Monochoria vaginalis (27.8%) > Echinochloa crus-galli (16.6%) and Cyperus difformis (16.6%). This information could be useful for estimation of future herbicide-resistant weed and establishment of herbicide-resistant weed control methods in Jeonbuk province, Korea.

• Korean Journal of Weed Science
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• v.17 no.3
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• pp.262-268
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• 1997

The experiment was carried out to obtain the basic information of weed control in lowland rice field in Gyeongbug province. The results were as follows : In weed distribution on life cycle, annual weed was occupied by 56.5% and perennials were 43.5%, respectively. In morphological distribution of weeds, grass weed was 25.2%, sedges was 12.3% and broad leaf weeds was 62.5%. In particular, weed occurrence of grass weed was much more increased than that of 1971 and 1981 year. Dominant weed species was Echinochloa crusgralli, Sagittaria trifolia, Eleocharis kuroguwai and Monochoria vaginalis in plain land, mid alpine area, and cold salty wind area. Dominant weeds was approximately similar occurrence in normal soil and poorly drained soil Gelds, but sandy soil field was not. Echinochloa crusgalli was dominant in hand transplanting and direct seeding on dry paddy field. Meanwhile, in machine transplanting, Sagittaria trifolia and Ludwigia prostrate were dominant, and occurrence of Echinochloa crusgalli was increased to delaying transplanting. As a result, major dominant weed was Echinochloa crusgalli, Sagittaria trifolia, Ludwigia prostrate, Eleocharis kuroguwai, and Monochoria vaginalis in terms of predominance.

• The Korean Journal of Pesticide Science
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• v.5 no.4
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• pp.33-39
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• 2001

An isolate of the indigenous fungus Pythium myriotylum was isolated from Monochoria vaginalis in Yusung, Korea in year 2000 and evaluated potential as a biocontrol agent in laboratory and greenhouse. P. myriotylum MD2 grew in a wide range of temperature regimes and the optimal growth temperature was $35^{\circ}C$. The fungus was highly pathogenic to Monochoria vaginalis at 30 to $35^{\circ}C$. Several weeds such as Rotala, indica, Lindernia procumbens, Ludwigia prostrata, Cyperus difformis, Scirpus juncoides, Aneilema keisak were also susceptible to the fungus, but Echinochloa crus-galli was not. The fungus affected the growth of rice seed germinated, but not to rice seedlings of 1- to 3-leaf stage. A total of 12 rice cultivars (3- to 4-leaf stage) tested showed no disease symptoms when inoculated with the fungus. Eleven crops, including Chinese cabbage, corn, soybean except wheat were immune to the infection of the fungi. These data suggest that P. myriotylum MD2 has a potential as a mycoherbicide to control weeds in paddy fields.

• 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 CROP SCIENCE
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• v.25 no.4
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• pp.17-27
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• 1980

All types of weed community became dominant by Monochoria vaginalis (Burm.) Presl. as the nitrogen level increased. The importance value (IV.) of M vaginalis rapidly increased with increasing nitrogen level whereas the LV. of other weed species decreased. At the 10 $\times$ 10cm plant spacing, M. vaginalis was almost totally suppressed at all nitrogen levels. At the 20 $\times$ 20cm plant spacing, the degree of suppression declined with increasing nitrogen level. At the 30 $\times$ 30cm plant spacing, there was no suppression of M vaginalis at the highest nitrogen level. The yield obtained at the 10 $\times$ 10cm plant spacing when M. vaginalis was present was not significantly different from that obtained from the weed free plot for all rice cultivars while it was significantly reduced by M vaginalis competition at the 20 $\times$ 20cm and 30 $\times$ 30cm plant spacings. The difference in yield caused by M vaginalis competition was primarily due to a reduction in the number of panicles at all nitrogen levels. There was a high negative correlation between grain yield and weed weight at heading. The yield reduction due to weed competition varied depending upon the nitrogen level.

• Korean Journal of Medicinal Crop Science
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• v.19 no.6
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• pp.407-413
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• 2011

This study was analyzed and investigated to evaluate ecological distribution of medicinal plants in Miho Stream of Korea. Totality 463 taxa of vascular plants were appeared in lower part of Miho Stream. Medicinal plants were distributed 253 taxa, which were 54.6% of the total vascular plants appeared. Medicinal plants of official drug compendium(Korean pharmacopoeia) were 85 taxa. Medicinal plants were distributed most of the forest area, and followed field surrounding, stream surrounding and paddy surrounding respectively. The distribution of life form hemicryptophyte was the most frequent. Plant community of appearing area of medicinal plants was classified into Salix koreensis, Phragmites japonica, Echinochloa crusgalli, Artemisia selengensis, Miscanthus sacchariflorus, Setaria faberii, Panicum dichotomiflorum, Bidens frondosa, Humulus japonicus, Monochoria vaginalis var. plantaginea, Eleocharis kuroguwai, Erigeron acris, Pinus densiflora, Pinus rigida, Quercus acutissima, Quercus serrata, Robinia pseudoacacia and Castanea crenata community. Medicinal plants in plant communities that occur frequently were Humulus japonicus, Corylus heterophylla and Liriope spicata.

• Korean Journal of Weed Science
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• v.31 no.4
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• pp.401-404
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• 2011

Bromobutide, a paddy field herbicide, can effectively control annual and perennial weeds. It has an excellent weeding effect especially against Monochoria vaginalis and Scirpus juncoides etc. When it is mixed with other herbicides controlling weed spectrum and application timing can be broaden. Bromobutide has stable weeding effects regardless of field and weather conditions, and there is almost no phyototoxic effects to rice.

• Korean Journal of Weed Science
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• v.32 no.1
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• pp.52-56
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• 2012

The occurrence of sulfonylurea-resistant weeds has recently increased in Korea. A survey was performed to investigate major paddy field weeds and frequently used herbicides in Gangwon province, Korea in order to establish a system to efficiently control herbicide-resistant weeds. The dominant paddy field weeds included Monochoria vaginalis (14%), Sagittaria trifolia (14%), Scirpus juncoides (13%), and Echinochloa spp. (13%), and the most widely used herbicides were oxadiazon 12% EC (27%), butachlor 5% GR (20%), oxadiargyl 1.7% EC (16%), and benzobicyclon+imazosulfuron+pyriminobac-methyl 6.1% SC (14%) in Gangwon province, Korea. Many paddy rice growers considered Scirpus juncoides, S. trifolia, Echinochloa spp. and M. vaginalis as herbicide-resistant weeds. An extensive research deserves to be conducted to monitor occurrence of herbicide-resistant paddy weeds in Gangwon province, Korea.