• The Plant Pathology Journal
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• v.40 no.3
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• pp.310-321
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• 2024

Tomato yellow leaf curl virus (TYLCV) and tomato spotted wilt virus (TSWV) are well-known examples of the begomovirus and orthotospovirus genera, respectively. These viruses cause significant economic damage to tomato crops worldwide. Weeds play an important role in the ongoing presence and spread of several plant viruses, such as TYLCV and TSWV, and are recognized as reservoirs for these infections. This work applies a comprehensive approach, encompassing field surveys and molecular techniques, to acquire an in-depth understanding of the interactions between viruses and their weed hosts. A total of 60 tomato samples exhibiting typical symptoms of TYLCV and TSWV were collected from a tomato greenhouse farm in Nonsan, South Korea. In addition, 130 samples of 16 different weed species in the immediate surroundings of the greenhouse were collected for viral detection. PCR and reverse transcription-PCR methodologies and specific primers for TYLCV and TSWV were used, which showed that 15 tomato samples were coinfected by both viruses. Interestingly, both viruses were also detected in perennial weeds, such as Rumex crispus, which highlights their function as viral reservoirs. Our study provides significant insights into the co-occurrence of TYLCV and TSWV in weed reservoirs, and their subsequent transmission under tomato greenhouse conditions. This project builds long-term strategies for integrated pest management to prevent and manage simultaneous virus outbreaks, known as twindemics, in agricultural systems.

• Korean Journal of Weed Science
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• v.15 no.1
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• pp.13-18
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• 1995

This experiment was carried out to investigate occurrence ecology and control of soil-flakes in flood-direct seeded rice field. The occurrence of soil-flakes were inhibited in blue light of 450nm wave length and promoted in red light of 660nm wave length. The diatoms of Pinnularia spp. largely occurred in low fertilizer level and which much more increased when nitrogen was mixed with thinly soil depth. The diatoms of Pinnularia spp. were effectively controlled by carbamate and triazine herbicides when treated in pre-emergence of soil-flakes. Beside, triazine herbicides, simetryne, dimethametryn, prometryne 5g ai/10a showed high control effect in pre and post-emergence of soil-flakes. Expecially, In water-direct seeded rice pyrazosulfuron-methyl molinate simetryne 5.37% GR and dimepiperate bensulfuron dimethametryn 7.643% GR showed high control effect on the soil-flakes when treated at 10 days after seeding and didn't showed rice injury.

• Weed & Turfgrass Science
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• v.3 no.4
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• pp.284-291
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• 2014

We surveyed the distribution of exotic weeds in the 350 upland crop fields of Gyeonggi-do. The exotic weeds were summarized as 78 taxa including 19 families, 52 genera, 74 species and 4 varieties. Among the total exotic weeds, the summer annuals were 48.7%, the winter annuals 28.2%, and the perennials 23.1%. Compositae was dominant family (32%), followed by Gramineae (8%), Polygonaceae (8%) and Malvaceae (7%). Dominant exotic weeds in northern Gyeonggi-do were Amaranthus lividus, Ambrosia trifida, Chenopodium album, Bidens frondosa and Erigeron Canadensis, and in southern Gyeonggi-do were Chenopodium album, Erigeron Canadensis, Erigeron annuus, Taraxacum officinale and Galinsoga ciliate. The most dominant exotic weeds in the Gyeonggi-do were Chenopodium album, followed by Amaranthus blitum, Erigeron canadensis. Canonical correspondence analysis for investigation of correlation between exotic weeds occurred in northern and southern Gyeonggi-do showed that the exotic weeds in northern Gyeonggi-do were more diverse then in southern Gyeonggi-do. This information could be useful for establishment of exotic weed control methods in Gyeonggi-do.

• Korean Journal of Environment and Ecology
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• v.17 no.3
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• pp.232-241
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• 2003

Mountain Chungyeong, 879m in altitude, is located in the northeast of the middle area in Korea. Around Mt. Chungyeong, many Korean endemic and rare plants are populated, so it is considered a very important biogeographical area where the temperature zones of northern and southern plants are crossed. Because it is close to Seoul, a capital of Korea, it is a common mountain where many tourists visit frequently. Continuous tourist's visit may cause a bad influence on vegetation around the climbing paths. Therefor, weed community around the climbing paths on Mt. Chungyeong, where visitors exert a bad influence directly on its community by coming in and out, was surveyed phytosocialogically. Our surveys have been accomplished from August, 2001 to September, 2002. weed communities formed around the climbing paths on Mt. Chungyeong were divided into several patterns and analysed. They have been divided into 5 communities and 5 subcommunities. Community A: Plantago asiatica community, A-a: Erigeron annuus subcommunity, A-b: Carex. lanceolata subcommunity, B: Pseudostellaria palibiniana community, B-a: Carex siderosticta subcommunity, B-b: Galium trachyspermum subcommunity, C: Pueraria thunbergiana community, D: Lespedeza maximowiczii community, E: Rubus crataegifolius community, F: Oplismenus undulatifolius community, The flora surveyed in these communities was constituted of 47 families, 101 genera, 17 varieties, and 149 species. Wild plants such as Plantago asiatica, Erigeron annuus, Erigeron strigosus, Pueraria thunbergiana, Lespedeza maximowiezii, Rubus crataegifolius, Artemisia princeps var. orientalis, Artemisia japonica and Lysimachia clethroides were mostly light loving plants and higher resistant plants against the stamping pressure. Our result from the ranking all surveyed areas by the Bray-Curtis ordination method was very similar to the results from phytosocialogical table analysis.

• Korean Journal of Weed Science
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• v.17 no.2
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• pp.147-156
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• 1997

The survey of weed population in apple orchard was conducted to investigate basic information on weed flora and its ecology at 27 locations in 1996. The weed species observed include 7 species of grasses, 60 species of broadleaves and 2 species of sedges, and the ratio of annual weed vs perennial weed was 64 : 36. Major dominant weed species by frequence were Chenopodium album, Capsella bursa-pastoris, Digitaria sanguinalis, Rorippa islandica, Alopecurus aequalis and Erigeron canadensis. While, on the basis of dry weight, the most dominant weeds were C. album followed by E. canadensis, A. aequalis, R islandica and R indica. The dominant weed species in middle-north Kyeongbuk region were C. bursa-pastoris, C. album, R indica and R islandica, were E. canadensis, Persicaria hydropiper, A. aequalis and Arenaria serpylliforia in Chungbuk region and were A. aequalis, E. canadenris and R islandica in Honam region.

• Weed & Turfgrass Science
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• v.2 no.4
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• pp.413-420
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• 2013

The climate change affects the growth and development of weeds as well as the outbreak of weeds. Especially, the occurrences of problematic paddy weeds due to climate change might cause the difficulties in weed control. This study therefore, investigated the current dominance and distribution of paddy weeds. As a result of the study on paddy weeds in northern Gyeonggi-do, there were total of 65 taxonomy groups including 23 family, 41 genus, 57 species, 7 subspecies and 1 variety. Among all the plants, 46 species were annual plants and 16 were perennial plants. Echinochloa crus-galli was the highest in importance analysis and the followings were in order of Ludwigia prostrate and Lemna paucicostata. The similarity of different paddy weeds in different regions observed through TWINSPAN analysis was distinguished by Fimbristylis miliacea, Rotala indica and Cyperus flaccidus. Regional differences shown in CCA analysis using weed species and soil environment revealed that Gimpo-si and Namyangju-si has difference soil and weeds, which are features that distinguished them from other regions. In northern Gyeonggi-do the result of paddy weed research showed the interregional difference not in dominant weeds but in distribution species.

• Weed & Turfgrass Science
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• v.1 no.4
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• pp.24-30
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• 2012

This study was conducted to select the cover crops in organic apple orchard by estimating the coverage of each cover crops and time-periodic weed occurrence. Seeding of Festuca myuros and Trifolium repens showed high contents of soil organic matter and phosphorus as compared with control. Seeding of Trifolium sp., Hordeum vulgare and Secale cereal reduced relatively occurrence of weed in May and S. cereal among others showed the greatest effect in June. In July, seeding F. arundinaceae and Poa pratensis showed low coverage and a lot of weeds occurred in their field. Fifty one species were occurred as weeds and it needs to removal of high and broadleaf weeds such as Chenopodium ficifolium, C. album var. centrorubru and Humulus japonicus in spring to increase the rate of ground cover. P. pratensis having the lowest cover rate showed the similar dry weight of weeds as compared with control. Trifolium sp. and Persicaria hydropiper had a high correlation with contents of soil organic matter and C. album var. centrorubru had a correlation with contents of soil phosphorus by CCA analysis.

• Weed & Turfgrass Science
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• v.5 no.4
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• pp.219-224
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• 2016

This study was conducted to investigate the ecology of weed occurrence and to establish an economical paddy field weed control system for direct-seeded rice on water. The main problem weed among annual and perennial weeds was Eleocharis kuroguwai. The control effect of E. kuroguwai was low by the application of azimsulfuron + carfentrazone-ethyl + pyriminobac-methyl at the early stages of rice in directly seeded paddy fields, but most annual weeds including Echinochloa crus-galli were controlled. Also, the additional application of pyrazosulfuron-ethyl + thiobencarb GR at 20 days after first treatment or of bentazone SL at 43 days after the first treatment effectively controlled E. kuroguwai. Tuber formation of E. kuroguwai was inhibited by the additional application of pyrazosulfuron-ethyl + thiobencarb by 84%, but the dormancy rate of old tubers of E. kuroguwai under the soil was higher than that of E. kuroguwai tubers following single application of azimsulfuron + carfentrazone-ethyl + pyriminobac-methyl at the early stages of rice. Tuber formation was inhibited by the additional application of bentazone by approximately 87%, and the old tuber dormancy rate was low in the bentazone treatment. High amounts of old dormant tubers of E. kuroguwai were found in the weedy plots.

• Korean Journal of Environment and Ecology
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• v.13 no.3
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• pp.261-270
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• 1999

낙산복원사업 대상지의 생태계 회복을 위한 계획수립의 기초자료로 사용하기 위하여 부지 내 식생조사를 통해 자연환경을 평가하였다 현존식생도 녹지자연도 및 Hemeroby 등급을 통해 자연성을 평가한 결과 많은 면적이 산림으로서의 기능을 상실한 인공화된 지역이었다. 식생이 존재하는 지역 중 산림의 형태를 유지한 지역은 아까시나무군락을 유지하고 있었고 기타 지역은 휴경지, 논.밭 잡초군락이며 동시에 ruderal 식물군락으로 판명되었다. 성과주변에 식재한 수목은 총 67종 1,243개체였으며 그중 자생종이 27종(40.3%) 544개체(43.8%)였고 도입종과 귀화종 재배종이 각각 17%, 8.8%, 15.4%로 나타났다. 생활형 분석에서는 1,2년생 초본식물이 47%를 차지하였고 귀화율은 24.1%로 나타나 매우 불안정하고 교란된 환경인 것으로 판단되었다.

• Weed & Turfgrass Science
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• v.7 no.1
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• pp.1-14
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• 2018

We surveyed the distribution of exotic weeds in Korean paddy fields, uplands, orchards and pastures from 12,568 sites during 3 years, 2013, 2014 and 2015. As a result, 166 species in 28 families were identified and 7, 130, 126, and 80 species were surveyed from paddy fields, uplands, orchards, and pastures, respectively. Among the 166 species, 128 species were annual weed and 38 species were perennial weed. Especially, winter annual exotic weeds were 63 species (37.8%). 46, 16, and 104 exotic weeds were classified to their introduction period of $1^{st}$ (1876-1921), $2^{nd}$ (1922-1963), and $3^{rd}$ (1964-now) period, respectively. The exotic weeds introduced in $2^{nd}$ and $3^{rd}$ period, included 12 Invasive Alien Species. The weeds from $1^{st}$ period, however, could be grouped into native weeds as the 'naturalized weed' and managed the same as the native weeds. Especially, some exotic weeds such as common groundsel were widely distributed in Korean crop lands, and they will become more problematic in near future. Therefore, systemic research from the biology to management should be conducted and the results from the studies should be applied practically.