• Weed & Turfgrass Science
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• v.5 no.2
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• pp.60-64
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• 2016

Investigation on weed flora in Lycium chinense upland fields was conducted to understand the current status of weed flora and establish the control measures. Investigation was conducted twice, May and June on 2015. From this investigation, 91 species of 30 families including 27 exotics were identified into 36 species of annuals, 28 species of biennials and 27 species of perennials. Dominance was the highest with Portulaca loeracea followed by Digitaria ciliaris, Stellaria media, Oxalis corniculata, Acalypha australis, Chenopodium album, Cyperus iria etc. in order. Chenopodium album was the highest in importance analysis and the followings were in order of Conyza canadensis, Conyza bonariensis, Senecio vulgaris, Amaranthus lividus, Sonchus asper etc.

• Weed & Turfgrass Science
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• v.3 no.4
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• pp.262-268
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• 2014

This study was conducted to provide basic information for weed control by surveying the occurrence of weed species. Surveys of weed species occurred in food crop (barley, maize, potato, soybean) fields were conducted in Chungnam province from April to September in 2014. Total 321 sites of food crop fields in 17 City / Gun in Chungnam province were investigated. From the result of this survey, 130 weed species in 36 families were identified and classified to 77 annuals, 27 biennials and 26 perennials. Based on the occurrence ratio, the most dominant weed species in Chungnam province food crop fields were Digitaria ciliaris (10.19%), followed by Conyza canadensis (7.82%), Portulaca oleracea (5.22%), Chenopodium album var. centrorubrum (5.21%), Capsella bursa-pastoris (3.47%) and Alopecurus aequalis (3.47%). Forty-four exotic weed species were identified. This information could be useful for estimation of future weed occurrence, weed population dynamics and establishment of weed control methods in food crop fields of Chungnam province.

• Weed & Turfgrass Science
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• v.5 no.2
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• pp.71-81
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• 2016

This study was conducted to investigate the weed occurrence and distribution on the orchard fields (apple, pear, peach, grape) at 387 sites in Chungbuk province of Korea from May to September in 2015. From the result of this survey, 200 weed species in 47 families were identified and classified to 82 annuals, 40 biennials and 78 perennials. Based on the occurrence ratio, the most dominant weed species in Chungbuk province orchard fields were higher in order of Digitaria ciliaris (4.12%), Echinochloa crus-galli (3.60%), Stellaria aquatica (3.45%), Artemisia princeps (3.07%) and Chenopodium album (3.06%). The composition of major occurred weed families, Compositae, Poaceae, Leguminosae and Cyperaceae were 21, 9, 6 and 6%, respectively. Coefficient of similarity between a various orchards based on the degree of dominance were ranged from 68.7-91.8%. The most important weed species at apple, peach, grape was Digitaria ciliaris while these for pear was Poa annua. Fifty-one exotic weed species were also identified. The results of this study could be useful information for estimation of future weed occurrence, weed population dynamics and establishment of weed control methods on the orchard fields in Chungbuk province of Korea.

• Weed & Turfgrass Science
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• v.4 no.3
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• pp.209-218
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• 2015

This study was conducted to investigate the weed occurrence and distribution on the upland crop fields (garlic, barley, potato, maize, red pepper, soybean and Chinese cabbage) at 795 sites in Chungbuk province of Korea from Apr. to Oct. in 2014. From the result of this survey, 188 weed species in 42 families were identified and classified to 96 annuals, 40 biennials and 52 perennials. Based on the occurrence ratio, the most dominant weed species in Chungbuk province upland crop fields were higher in the order of Portulaca oleracea (8.14%), Digitaria ciliaris (6.72%), Echinochloa crus-galli (6.55%), Rorippa palustris (6.00%) and Chenopodium album (5.89%). The composition of major occurred weed families, Compositae, Poaceae, Polygonaceae and Cruciferae were 19, 10, 7 and 6%, respectively. In the winter upland crop fields, the dominant weeds were in the order of Capsella bursa-pastoris (12.36%), Alopecurus aequalis (11.05%) and Stellaria alsine (8.42%). In the summer upland crop fields, the dominant weeds were in the order of Portulaca oleracea (8.58%), Digitaria ciliaris (7.18%) and Rorippa palustris (6.28%). Fiftythree exotic weed species were identified. The results of this study could be useful information for estimation of future weed occurrence, weed population dynamics and establishment of weed control methods on the upland crop fields in Chungbuk province of Korea.

• 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.2 no.2
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• pp.170-175
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• 2013

Korea is carrying out weed quarantine by plant quarantine regulations including heat-treatment method to prevent the influx of exotic weeds. In order to confirm suitability for current heat-treatment criteria and find field-applicable methods which can completely devitalize quarantine weed seeds, the conditions for heat-treatment with/without 40% relative humidity were studied with 9 species among quarantine weed seeds and one weed species similar to quarantine weed. Dry heat-treatments had been tested under various temperatures and time conditions. All seeds were dead at the conditions of $95^{\circ}C$ for 48 hours, $100^{\circ}C$ for 36 hours, $110^{\circ}C$ for 24 hours, $121^{\circ}C$ for 4 hours and $130^{\circ}C$ for 30 minutes. Heat-treatments at 40% relative humidity resulted in complete seed death at the conditions of $85^{\circ}C$ for 36 hours and $90^{\circ}C$ for 16 hours. The above results show that current heat-treatment criteria are not suitable for several quarantine weeds and these conditions could be applied as a quarantine method to prevent the influx of quarantine weeds along with agricultural imports. More specific conditions for heat tolerant species such as Picris echioides and heat susceptible species such as Cuscuta spp. are necessary and will improve plant quarantine process in devitalizing quarantine weed seeds with different heat tolerances.

• Weed & Turfgrass Science
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• v.3 no.2
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• pp.102-109
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• 2014

This study was conducted in order to utilize the basic data for weed control by surveying the occurrence of weed species and the degree of damages caused by those weeds occurred in cultivated Coix lacryma-jobi var. mayuen fields. Survey was carried out three times, from June to September in 2013. The weed flora was composed of a total of 98 weeds, 33 family, of which 58 species were annual, 21 species were biennial, and 19 were perennial plants. Thirty-one exotic species were included as well. Dominance was the highest with Digitaria ciliaris followed by Acalypha australis, Echinochloa crus-galli, Portulaca oleracea, Bidens frondosa etc. in order. In the PCA plot analysis, weeds occurred in C. lacryma-jobi var. mayuen fields were divided into three groups, Panicum dichotomitlorum community, Echinochloa crus-galli-Sigesbeckia pubescens community and Acalypha australis community. Yield of C. lacryma-jobi var. mayuen was reduced 60% in no weeding plots comparing to that in weed management plots.

• Weed & Turfgrass Science
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• v.3 no.2
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• pp.95-101
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• 2014

This study was conducted in order to utilize the basic data for weed control by surveying the occurrence of weed species and the degree of damages caused by those weeds occurred in cultivated Ligularia fischeri fields. Survey was carried out five times, on May, June, July, August and October in 2013. The weed flora was composed of a total of 104 weeds, 37 families, of which 55 species were annual, 25 species were biennial, and 24 were perennial plants. Twenty-six exotic species were included as well. Dominance was the highest with Chenopodium album followed by Stellaria aquatica, Echiochloa crus-galli, Conyza canadensis, and Artemisia princeps etc. in order. In the PCA plot analysis, weeds occurred in cultivated L. fischeri fields were divided into three groups, Persicaria thunbergii-Bidens frondosa community, Chenopodium album community and Capsella bursapastoris community. The degree of damages in cultivated L. fischeri fields was investigated by weighing roots of L. fischeri. We found that 56% decreased root weight in no weeding plots comparing to that in weed management plots. We infer from this result that decreased roots will affect to the growing of L. fischeri in following year.

• Weed & Turfgrass Science
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• v.4 no.2
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• pp.85-94
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• 2015

The weed flora in the mulberry fields were investigated in Suwon, Jeonju, and Buan in May, July, and September 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 in the Korean mulberry fields. The survey was conducted in 53 regions, covering approximately $145,925m^2$. Altogether 153 weed species of 37 families were identified, of which 68 were annual, 39 species were biennial and 46 were perennial. The dominance was the highest with Digitaria ciliaris followed by Erigeron annuus, Chenopodium album, Echinochloa crus-galli var.crus-galli, Acalypha australis, Commelina communis etc. Exotic weeds presented 44 species with 28.8% of a total presence, of which Erigeron annuus was the highest, followed by Chenopodium album, Phytolacca americana, Conyza canadensis, Oxalis corymbosa etc. Especially, we should aware Senecio vulgaris, not controlled with glufosinate ammonium SL in the Korean mulberry fields because it was known as atrazine resistance in US, Canada, Germany etc. In the PCA plot, weeds presented in the mulberry fields were divided into two groups, Eclipta prostrata community and Stellaria aquatic community and weed flora of Suwon and Buan were different due to those only presented in Suwon.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.114-114
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• 2022

There are 28 families and 166 species of exotic weeds on agricultural land and among these, 23 families and 80 species of exotic weeds occur on pastures. Among them, the Solidago altissima is a perennial weed belonging to the asteraceae family and it is an exotic weed that spreads to the surrounding area using methods such as high seed production, vegetative propagation using underground rhizomes and allelochemical. Accordingly, in 2009, the Ministry of Environment designated it as an ecosystem-disrupting species. This study was conducted to obtain basic data about the effects of S.altissima derived allelochemicals on forage crops. The root of S.altissima was separated, dried in the shade and then pulverized to prepare an root powder. Powder was repeatedly extracted with methanol for 3 days and concentrated under reduced pressure to obtain an root methanol extract. Dissolve the extract in distilled water, dispense it in a separate-funnel and proceed with liquid-liquid extraction by adding equal amounts of n-haxane (Hex), chloroform (CHCI₃), ethyl acetate (EtoAC), and butanol (BuOH) in order of increasing polarity. A seed-bioassay was performed using fractions for each solvent, followed by separation and purification by silica gel column chromatography. As a result of the fraction germination test for each solvent, the IC₅₀ values using the fresh weight of each fraction were 898.3 mg L^-1, 676.3 mg L^-1, 1160 mg L^-1 and 1360 mg L^-1. CA, CB, and CC fractions were obtained through primary silica gel column chromatography that used CHCI₃ fraction. As a result of seed-bioassay using each fraction, the IC₅₀ values for the fresh weight of each fraction was 537.3 mg L^-1, 1280 mg L^-1 and 1947 mg L^-1. Based on this, 5 fractions were obtained as a result of secondary silica gel column chromatography using the CA fraction. A seed-bioassay was performed, as a result, the lowest IC₅₀ value was calculated as 226.7 mg L^-1 in the CAE fraction. Based on this, the fraction was analyzed by GC-MS. The results of this study can be used as basic research data on the effects of weeds on forage crops and allelochemicals secreted from S. altissima.