• Weed & Turfgrass Science
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• v.4 no.3
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• pp.176-187
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• 2015

The weed flora in the Codonopsis lanceolata upland fields were surveyed in Hoengseong and Jeju in May, August, and October of 2014. The objectives of this study were to use the survey data for establishing weed control methods and to bring awareness of possible problematic weeds occurred in C. lanceolata upland fields in Korea. Altogether 207 weed species of 47 families were identified, of which 87 were annual, 47 species were biennial and 73 were perennial. Based on the morphological characteristic of the leaves, 182 species were broad leaves, 18 species were grasses, and 7 species were sedges. The dominance was highest in the Artemisia princeps followed by Digitaria ciliaris, Commelina communis, Persicaria longiseta and Echinochloa crus-galli etc. Fifty-nine species were exotic weeds with 29% of a total presence, of which Erigeron annuus was highest, followed by Crassocephalum crepidioides, Bidens frondosa, Hypochaeris radicata etc. In the PCA plot, weeds presented in the C. lanceolata upland fields of Hoengseong were divided into three groups, E. annuus, Sigesbeckia pubescence and C. communis communities and those of Jeju were divided into four groups, C. crepidioides-Cyperus iria, Spergula arvensis, Poa annua and Youngia japonica communities.

• 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.18 no.4
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• pp.314-324
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• 1998

This study was carried out to investigate the herbicidal action characteristics of EK3143 and EK3150, newly synthesized cyclohexanedione analogues, and their inhibitory effects on the acetyl-CoA carboxylase activity isolated from various plants. Sethoxydim, a typical cyclohexanedione herbicide, had a high herbicidal activity against only grasses with growth inhibition, leaf chlorosis and necrosis. EK3143 and EK3150 had a lower effect against grasses but a higher effect against broadleaf plants such as black nightshade and velvetleaf than sethoxydim had. Low rate application of EK3143 induced leaf bleaching(whitening), while high rate application induced the same symptoms as those of sethoxydim. EK3150 induced more significant whitening, additionally accompanying a curling of meristem part in broadleaf plants. A consistant tendency was observed between the growth inhibition against grasses and the senstivity of grass ACCase to these compounds, but not between herbicidal activities against broadleaf plants and the senstivity of dicotyledonous ACCase; i.e. EK3150, which had higher herbicidal activity against black nightshade and velvetleaf than EK3143 had in greenhouse, rather showed lower ACCase inhibition. In EK3150-treated barnyardgrass, growth inhibition occurred prior to decrease of photosynthetic pigments, in contrast to that of norflurazon and EK3140. These results suggest that EK3143 and EK3150 may have two target sites, ACCase and an unknown site on fatty acid synthesis related to growth inhibition and bleaching respectively, and their symptoms would be appeared in different degree by a differential binding affinity between two action sites.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.4
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• pp.337-342
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• 2012

This study was conducted to evaluate the weed suppressing effects of different cropping system including hairy vetch and rye cover crops, polyethylene plastic film, and transplanting film mulching in direct sowing and transplanted foxtail millet field in 2011. Crop growth and development and weed occurrences in the fields were examined to know the efficiency of proposed cropping system. In polyethylene film mulching treatment, heading date of foxtail millet was earlier by 4 days than control, on the other hands, rye cover crop mulching delayed heading date by 8 days. Besides the effect of cover crop on the heading of foxtail millet, the residues changed growth characteristics. Plant height of foxtail millet was increased by 92.4% at hairy vetch treatment although the height of was reduced by 63.7% in the rye cover crop treatment. Hairy vetch treatment showed beneficial effects on foxtail millet growth reduced the occurrences of grasses and broadleaf weeds higher than 90%, as compared to control in foxtail millet fields. While rye cover crop treatment showed poor foxtail millet growth reduced less strongly grasses and broad-leaf weeds by 47% and 90%, respectively. At harvest, yield of foxtail millet was greater in order of hairy vetch cover crop > polyethylene film mulching > rye cover crop ${\fallingdotseq}$ control in both transplanted and direct sown fields.

• The Korean Journal of Pesticide Science
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• v.6 no.3
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• pp.183-192
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• 2002

Herbicidal effect of KSC-35089, a newly synthesized N-arylphthalimide compound, was examined, and its interaction with quizalofop-P-ethyl when foliar applied as a tank-mixture was evaluated under a greenhouse condition. KSC-35089 showed stronger herbicidal activity on broadleaves than grasses, suggesting that it would be an appropriate partner for non-selective weed control with quizalofop-P-ethyl, a strong grasskilling ageant. In general, the interaction between KSC-35089 and quizalofop-P-ethyl appeared to be additive, which indicates each compound acts on whole plant level independently. This additive interaction was confirmed in a spectrum test using 19 grasses and 26 broadleaves. Under the greenhouse condition, all tested plants were controlled around 90% level through a foliar application with a tank-mixture of KSC-35089 at 64 g ai/ha and quizalofop-P-ethyl at 32 g ai/ha. Further study would be required on the action mechanism of this additive interaction.

• Korean Journal of Weed Science
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• v.8 no.2
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• pp.164-168
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• 1988

In order to get basic information for establishing weed control methods in apple orchards, weed distribution was surveyed at 2 locations in Chungnam Province at 15 days intervals. In apple orchard 48 weed species (18 families) were distributed and Chenopodium album and Polygonum hydropiper were dominated and Digitana sanguinalis, Portulaca oleracea, and Erigeron canadensis were also abundant among them. Highest number of weeds emerged in April and dry weight of weeds were heavy in June and October, especially in summer broadleaf weeds and winter broadleaf weeds, and winter grasses were abundant in spring. Seasonal Shannon's diversity index(H'), maximum diversity(H max'), eveness (J') for the Shannon diversity index, and Simpson index were high in apple orchards. Interspecific competition was more severe than intraspecific competition.

• Weed & Turfgrass Science
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• v.7 no.1
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• pp.76-86
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• 2018

Turfgrass species were evaluated for their rooting and foliar characteristics, and their interaction with the soil. The rooting system was divided into three compartments, one above another, such that the top and bottom compartments of the root system could be supplied with a nutrient deprived solution. Exposure of parts of the roots to nitrate deprivation caused a localised retardation of root initiation and extension, compared with zones receiving the full supply of nutrients. This resulted in considerable modification to root form, coupled with a significant depression in foliar growth. The extension of roots was the least affected by the deprivation of potassium. Phosphate and calcium deprivations gave rise to similar responses in root and foliar formation. Results from this study showed that external concentrations of nitrogen, phosphorus, potassium and calcium are required by the root system in varying amounts for optimal growth of roots. Turfgrass coverage and turf quality ratings further reinforced these findings. No significant difference was observed between the different grasses examined here. All three species responded similarly to the deprivation of the various nutrients. Results from this study confirmed that targeted fertilization programs are beneficial and can help reduce cost, chemical usage and prevent leachate and contamination.

• Weed & Turfgrass Science
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• v.7 no.3
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• pp.239-245
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• 2018

Comparative drought resistances of 11 perennial warm-season turfgrasses were evaluated in the field after withholding irrigation for 48 days in summer I and 57 days in summer II. There were significant variations among the grasses in their drought resistances. From two years study of field shoot recovery from drought stress, the relative rankings among the 11 warm-season turfgrasses was as follows. 'Arizona Common' and 'Texturf 10' bermudagrasses [Cynodon dactylon (L.) Pers.], 'Tifgreen' hybrid bermudagrass [C. dactylon (L.) Pers. ${\times}$ C. transvaalensis Davy], and 'Georgia Common' centipedegrass [Eremochloa ophiuroides (Munro.) Mack.] possessed good drought resistances, whereas 'Texas Common' St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] and 'Tifway' hybrid bermudagrass [Cyndon dactylon (L.) Pers ${\times}$ C. transvaalensis Davy] possessed poor drought resistances. 'Texas Common' buffalograss [Buchloe dactyloides (Nutt.) Engelm.], 'Pensacola' bahiagrass (Paspalum notatum Flugge.), and 'Adalayd' seashore paspalum (Paspalum vaginatum Swartz), 'Meyer' zoysiagrass (Zoysia japonica Steud.), 'Emerald' zoysiagrass (Z. japonica Steud. ${\times}$ Z. tenuifolia Willd. ex Trin.) were found to rank intermediate. Visual leaf firing showed the highest correlation (r=-0.84) to shoot recovery from drought stress. Visual leaf rolling (r=-0.59) and canopy-air temperature differential (r=-0.64) also showed very significant correlations, whereas leaf water potential (r=0.54) showed relatively lower correlation.

• Weed & Turfgrass Science
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• v.4 no.4
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• pp.383-389
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• 2015

The use of zoysiagrass (Zoysia japonica Steud.) in the transition zone is limited because of a lack of cold hardiness although zoysiagrass has many advantages compared to other warm-season and cool-season grasses. Late-fall N fertilization is often applied for darker green color of turfgrass in early spring and more extensive root growth without rapid top growth. The objective of the study was to evaluate the effects of late fall N application and turf cover for zoysiagrass spring green-up. Clear polyvinyl chloride (PVC) film was used for turf cover. The amount of N applied were 5 and $10g\;N\;m^{-2}$ for the low and high N rate treatments, respectively. Covered zoysiagrass had greater turfgrass color and quality in early spring than non-covered zoysiagrass. The high N rate had 0.6 to 2.3 greater turfgrass quality than the low N rate on 7 of 9 rating dates. Slow-release N as late fall fertilization is more effective for turfgrass color and quality than fast-release N in spring. Turf cover could reduce the period of yellow zoysiagrass, and the earlier time of spring green-up could be advanced by increasing turfgrass quality and growth of zoysiagrass.

• Korean Journal of Organic Agriculture
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• v.19 no.spc
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• pp.127-128
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• 2011

Vinegar has been considered as a potential organic herbicide, but more knowledge is needed about acetic acid concentration, application volume and use of adjutants on weed control. In this study, we determined optimum acetic acid concentration and spraying time on several weed species. Vinegar is more effective in broadleaf weeds than grasses. Vinegar is also effective in controlling younger weeds such as $3^{rd}$ to $4^{th}$ weeks after emergency. For example, $3^{rd}$ weeks after emergency weeds were easily controlled at 2-3% of vinegar solution. But $4^{th}$ weeks after emergency weeds were controlled at 4-5% of vinegar. Therefore vinegar concentration was recommended about 5%, and application time was when the weeds were young-within 3 leaf stage.