• The Korean Journal of Mycology
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• v.29 no.2
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• pp.110-115
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• 2001

Nine species of Bipolaris, two species of Drechslera and two species of Exserohilum were identified from 66 isolates collected from leaf spots and leaf blights on gramineous hosts of field crops, grass pasture plants, turfgrasses and wild weeds in Korea in 1998. They included B. bicolor, B. coicis, B. cynodontis, B. maydis, B. oryzae, B. panici-miliacei, B. setariae, B. sorghicola, B. sorokiniana, D. dictyoides, D. graminea, E. oryzicola and E. turcicum. Of these, B. bicolor, B. sorghicola, D. dictyoides, and E. oryzicola were recorded for the first time in Korea.

• Plant Resources
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• v.7 no.1
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• pp.69-76
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• 2004

Lettuce (Lactuca sativa L.) is known to contain water-soluble substances that are biologically active. Aqueous or methanol extracts and residues from leaves of lettuce plants were assayed to determine their allelopathic effects, and the causative allelochemicals from fractions were quantified by means of HPLC analysis and bioassayed. Extracts from oven-dried leaf samples were more phytotoxic than those from freeze-dried samples. Leaf extracts of 40 g L$^{-1}$ were completely inhibitory on root growth of alfalfa (Medicago sativa L.), while root growths of barley (Hordeum vulgare L.) and soybean (Glycine max L.) were less sensitive. Early seedling growth of both alfalfa and barnyard grass (Echinochloa crus-galli) was significantly reduced by methanol leaf extracts. The major allelopathic substances analyzed by HPLC were coumarin, trans-cinnamic acid, o-coumaric acid, p-coumaric acid and chlorogenic acid. Of them p-coumaric acid was found as the greatest amount (8.9 mg 100 g$^{-1}$ ) in the EtOAc fraction; only coumarin was found in all the fractions. Hexane and EtOAc fractions of L. sativa reduced alfalfa root growth more than did BuOH and water fractions. These results suggest that lettuce had potent herbicidal activity, and that its activity differed depending on type and amount of causative compounds by fraction.

• Weed & Turfgrass Science
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• v.3 no.2
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• pp.86-94
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• 2014

Survey was carried out in paddy fields to investigate the dominance of weed species and weed occurrence on 200 fields of southern Gyeonggi region in Korea during the year 2013. We observed 3 species of grass, 5 species of sedge, and 11 species of broadleaf and other weeds. The most dominant weed species was Eleocharis kuroguwai, followed by Echinochloa crus-galli, Sagittaria trifolia, Monochoria vaginalis, Scirpus juncoides and Bidens tripartita. The dominance value of E. kuroguwai and B. tripartita decreased compared to the survey results performed in 2005 but that of M. vaginalis, S. juncoides, S. trifolia and E. crus-galli increased. Weed occurrence increased from 2.83 g in 2005 to 3.51 g in 2013 based on weed dry weight per $m^2$. Occurrence ratio of annual weeds to perennial weeds changed from 45.2% : 54.8% in 2005 to 45.8% : 54.2% in 2013. If we analyze dominance of weed species based on the rice transplanting timing, E. kuroguwai and E. crus-galli were the most dominant weed species at mid-May transplanting, and M. vaginalis and S. juncoides were the most dominant weed species at late- May transplanting, and M. vaginalis and E. kuroguwai were the most dominant weed species at early-June transplanting. Since paddy weeds resistant to sulfonylurea herbicides are expected to be continuously increased, the regular monitoring of their occurrence and efficient control methods should be considered in future.

• Journal of The Korean Society of Grassland and Forage Science
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• v.25 no.2
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• pp.97-104
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• 2005

This experiment was conducted to introduce strip croppings fur decreasing the damage of the continuous com cultivation at the experimental field of Grassland and Forage Crops division, National Livestock Research Institute from 1999 to 2000. Introduced mps for strip cropping to the continuously com cultivated field were red clover (RC), alfalfa(AL), and mixture of grass md legume. Fall panicum(FP), which is one of warm season's weeds was focused on its emerged quantity in com field changed by the level of soil water content and degree of the continuous corn cultivation. The ranges of yearly gained forage fresh yields including weeds like mainly FP were 119.4 ${\~}$ 169.6 in the continuous cultivation with com and rye and 64.9 ${\~}$ 83.3 ton / ha in the corn mono-cropping. Meanwhile, the percentages of pure com in continuous com cultivation plot were only $31-38\%$. This was for the mainly emergence of FP in the continuously com cultivated field. The ranges of average fresh yield of emerging FP were 45.6${\~}$63.4 ton/ ha in the continuously com cultivated field which were over the ranges of yields of rye, 28.2 ${\~}$ 41.6 ton/ ha. The dry matter yields of red clover, alfalfa and mixture with grass and legume introduced for strip cropping were 10.2, 10.6 and 10.6 ton / ha, respectively and these were about the 1/4 average fresh com yield. After strip cropping of red clover, alfalfa and mixture with grass and legume, the yields of corn increased to 56, 82, 88 and 79 ton / ha, respectively and com yield was much better in the alfalfa strip cropping.

• Journal of The Korean Society of Grassland and Forage Science
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• v.28 no.2
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• pp.119-128
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• 2008

The object of this experiment was to investigate the food habits of Korean native goats fed with various roughage sources. The feeding trials were conducted at Chungnam National University and Unbong Animal Genetic Resources Station in 2007. The experimental roughages sources were five including 25 species in all; grass sources: 5 species (Lolium perenne, Festuca arundinacea, Poa pratensis, Agrostis alba and mixed grass, legume sources: 5 species (Trifolium pratense, Medicago sativa, Trifolium repens, Melilotus officinalis and Vicia villosa), browse sources: 5 species(Quercus serrata Thunb., Prunus jamasakura Sieb., Quercus aliena Blume, Robinia pseudoaccacia and Pinus densiflora), weed sources: 5 species(Artemisia princeps Pampanini, Erigeron canadensis, Alopecurus aegualis Sobolewski, Echinochloa crusgalli var. frumentacea (Roxb.) Wight and Rumex crispus), and native grass sources: 5 species(Zoysia japonica Steudel, Agropyron tsukushiense var. transiens(Hack) Ohwi., Arundinella hirta(Thunb.) Tanaka, Miscanthus sinensis Anderss and Phragmites comunis Trin). Ten Korean native goats were selected which had nearly the same body weight(average 30.6kg, 남) as experimental animals. Experimental roughages were prepared by 0.5kg per 1 species fed to Korean native goats, and the experiment was carried out from 08:00 to 20:00. The chemical composition and dry matter digestibility of each roughage source and species were significantly different at the sampling area, plant species, growth stages and cutting period (p<0.05). The Korean native goats ate more roughages which had low fibrous contents, but high dry matter digestibility. Among all the 25 species of roughages, the favorite intake species order by Korean native goats was observed like this: Quercus serrata Thunb., Quercus aliena Blume, Trifolium repens, and Pinus densiflora and Artemisia princeps Pampanini which was lower intake compared to other domestic herbivores. On the other hand, compared to each roughage source, total intake amount by Korean native goats was showed as browse(29.9%), legumes(23.0%), weeds(21.6%), grasses(21.5%) and native grasses(4.0%), respectively. Based on the result, the food habit of Korean native goats seems to be closer to browser type.

• Korean journal of applied entomology
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• v.44 no.2
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• pp.115-123
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• 2005

Historical changes of population abundances of European red mite (ERM), Panonychus ulmi (Koch), and two-spotted spider mite (TSSM), Tetranychus urticae (Koch) (Acari: Tetranychidae), were described in selected apple orchards in the National Horticultural Research Institute (NHRI, Suwon, Korea), based on research reports of the NHRI from 1958 to 1998. ERM was an abundant species up to 1970, and TSSM became a dominant species after 1980. The change occurred around mid 1970. Three hypotheses were made to explain the change: TSSM competitively replaces ERM, ground cover weeds are a major influencing factor on movement of TSSM (TSSM movement into trees is accelerated by destroying weeds), and ERM and TSSM populations are regulated by natural enemy complexes when the orchard system is not disrupted. And long-term results of the interaction between two species were projected according to the combination of different orchard management strategies: pesticide sprays (non-selective toxic pesticide spray : heavy pesticide pressure (HPP), and selective soft pesticide spray = low pesticide pressure (LPP)) and weed control methods (grass planting, and clean culture system with herbicides). In the HPP and grass planting system, ERMs are abundant because ERM can avoid competition with TSSM as movement of TSSM to trees are restricted, and natural enemy complexes are destroyed by toxic pesticides. In the HPP and clean culture system, TSSMs are abundant because TSSM moves to trees from early season and competitively replaces ERM. In the LPP and grass planting system, ERMs are abundant because movement of TSSM to trees is reduced, but they do not build up a high population density since their densities are regulated by natural enemy complexes. In the LPP and clean culture system, TSSM moves to trees and competes with ERM, but the competition pressure is reduced because population densities of mites are regulated in a lower level by natural enemy complexes. So, ERM can occurs in late season. Thus, two species can coexist temporarily with more ERM in early season and more TSSM in late season. TSSM abundant phenomenon presented in this study can be partially explained as a result of long-term interaction between ERM and TSSM under the HPP and clean culture system.

• The Korean Journal of Pesticide Science
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• v.2 no.2
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• pp.102-107
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• 1998

The objective was to know if seed potato farmers in Kangwon alpine area control weeds effectively and use herbicides properly to control weeds. Seed potato farmers in Pyongcbang, Hoengsong, and Kangnung have noxious weeds, such as marsh pepper, lambsquarters, barnyard grass, mugwort, asiatic dayflower, hairy carbgrass, ladysthumb, common chickweed, field horsetail, and common purslain, in their farmyard. These are controlled by a combination of physical and chemical weed control methods. However, several weeds such as marsh pepper, field horsetail and, mugwort are poorly controlled by 2-fold amount of several herbicides, including paraquat, pendimethalin, and metribuzin (58% of the answered). Herbicides are not selected and used in a proper manner by seed potato farmers: most of farmers selected herbicides by their experience (51% of the answered) and dealers recommendation (34% of the answered), while only a few farmers of the answered took advantage of the Farmers Handbook for Herbicide Application. In addition, the selected herbicides, including non-registered ones such as paraquat and fluazifop-butyl, are applying three to five years in a succession. With these improper selection and usage of herbicides, sixty-seven percent of the answered farmers have experienced crop damage and seventy-five percent have poisoning. We conclude that a systemic educational program for the proper selection and use of herbicides is needed for seed potato farmers in Kangwon alpine area.

• The Korean Journal of Pesticide Science
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• v.3 no.3
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• pp.54-59
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• 1999

The objective was to know if corn growers at Hongchcel County, Kangwon-do, where corn is the major agricultural product, control weeds effectively and use herbicides properly to control weeds. Sixty-eight corn growers at Hongchon were participated in this survey. Corn growers have noxious weeds, such as hairy carbgrass, common purslane, lambsquarters, Asiatic dayflower, mugwort and barnyard grass in their corn fields. Forty-four percents of the answered corn growers control weeds by hand weeding, and the others by a combination of physical and chemical methods. Corn growers have a preference of paraquat and alachlor for a pre-emergence treatment (94% of the answered) and of paraquat, glufosinate, glyphosate and fluazifop-P-butyl for a post-emergence treatment (87% of the answered). Corn growers did not select and use herbicides in a proper manner. fifty-four percent of the answered corn fevers selected herbicides by their own experience and 18 percent by neighbors recommendation. Herbicides were not selected and used in a proper manner by corn growers: 54 percent of the answered selected herbicides by the experience of growers and 18 percent by the recommendation of neighbors. In addition, a half of the answered applied over two-fold higher amounts of herbicides than the recommended rate. With these improper- selection and use of herbicides, 37 percent of the answered have experienced the crop damage and 42 percent the herbicide poisoning. We conclude that the development of the educational program for the proper selection and use of herbicides is needed for corn growers in Kangwon-do.

• 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%.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.3
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• pp.241-250
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• 1999

A field plot experiment was carried out on mixed pasture from October 1995 to October 1997 to examine the effect of weed control as affected by the difference of mixed pasture species, planning with spilt plot design which main plots of 2 treatments (companion crop Italian ryegrass Lolium multiflorum and Kentucky bluegrass Poa pratensis) are divided into subplots of 4 treatments (T1: single companion crop, T2: Tall fescue Festuca arundinasea + Orchardgrass Dactylis glomerata + Ladino clover Trifolium repens, T3 : Perennial ryegrass Lolium perenne + orchardgrass + ladino clover, T4 : orchardgrass + ladino clover). Average 2 year-dry matter yields of companion crops as whole plots, Italian ryegrass and Kentucky bluegrass, were 15,437kg/ha and 14,629kg/ha, respectively and those of T1, T2, T3 and T4 as sub plots were 14,815, 15,407, 14,629 and 15,187kg/ha respectively without statistical1y significant difference(P>0.05). Though there was no significant difference between the dry matter yields of Italian ryegrass and Kentucky bluegrass, as whole plots, at 1st harvest of second year, dry matter yields of T3 and T4, as 4,591kg/ha and 4,816kg/ha respectively, were higher than those of T1, 3,376kg/ha(P<0.05), significantly. There was a significant difference among 2nd year-average DM yields of sub plots(P<0.05), showing highest with T4 15,131kg/ha and least with T1 13,085kg/ha and T3 13,269kg/ha. Italian ryegrass, as the companion crop, was better for the control of weeds in the early spring than Kentucky bluegrass, but reached to the similar botanical composition level with Kentucky bluegrass after summer with rapid decrease of Italian ryegrass. Percentage of Kentucky bluegrass in botanical composition increased slowly, but did'nt become an important factor for the control of weeds at the end of this experiment. Using orchardgrass in mixed pasture such as T2, T3 and T4 made weeds more decreased in mixed pasture than one in single conpanion crop. There was no difference among treatments of whole or sub plots in crude protein contents of pasture taken in this study. Contents of NDF and ADF of companion crop. Italian ryegrass plots harvested in October 1997 were hither than those of Kentucky bluegrass plots(P<0.05). ADF contents of Kentucky blue grass-plots taken in July 1997 has shown to be high significantly as compared to those of Italian ryegrass plots(P<0.01). The results of this study support that the companion crop Italian ryegrass was good for weed controls only in spring of 1st year after sowing and orchardgrass in mixed pastures played good roles for increase of dry matter yield and weed control.