Occurrence of Weed Species in Pear Orchards in Chungnam Province of Korea

Jia, WeiQiang,Hwang, Ki Seon,Won, Ok Jae,Oh, Taek-Keun,Shinogi, Yoshiyuki,Park, Kee Woong FACULTY OF AGRIC PUBLICATIONS-KYUSHU UNIV 2017 Journal of the Faculty of Agriculture, Kyushu Univ Vol.62 No.1

<P>A survey of weed occurrence was conducted to identify noxious weed species in pear orchards to obtain basic information for effective weed control. The survey was conducted in pear orchards situated in Chungnam province of Korea from April to June 2015, for spring, and from September to October 2015, for autumn. A total of 19 survey sites were randomly selected. The weed species were summarized as a total of 63 taxa belonging to 24 families. Specifically, 18 exotic weeds, belonging to 9 families, were identified. The majority of weeds were Compositae (10), followed by Poaceae (7) and Polygonaceae (6). Rumex crispus and Poa annua were dominant weeds. In terms of life cycle, there were 17 species of annual weeds, 13 species of biennial weeds, and 17 species of perennial weeds for the spring survey, and 15 species of annual weeds, 6 species of biennial weeds, and 11 species of perennial weeds for the autumn survey. The continuous application of single control method was unbeneficial for weed management in pear orchards. These results could be useful for the establishment of weed multi-control methods in pear orchards in Chungnam province of Korea.</P>

Weed Flora and Management Practices in Peach Orchard Fields in Korea

Jia, WeiQiang,Hwang, Ki Seon,Won, Ok Jae,Lee, In-Yong,Lee, Jeongran,Roh, Suk-Won,Park, Kee Woong The Korean Society of Weed ScienceThe Turfgrass So 2017 Weed & Turfgrass Science Vol.6 No.2

This study was carried out two surveys in 2015 to monitor weed occurrence and determine the most troublesome weeds in peach orchards of Korea. The first survey identified 56 taxa belonging to 23 families including 27 annuals, 11 biennials, and 18 perennials. Based on importance values, Conyza canadensis (5.12%), Plantago asiatica (4.17%), and Trifolium repens (3.86%) were the dominant weeds in the first survey (from April to June). Seventeen exotic weeds were identified in the first survey, including Conyza canadensis, Trifolium repens, and Chenopodium ficifolium. The second survey (from September to October) identified 42 weeds belonging to 19 families including 23 annuals, 5 biennials, and 14 perennials. According to importance values, Digitaria ciliaris (8.00%) was the most dominant weed, followed by Echinochloa utilis (6.61%) and Rorippa palustris (6.48%). There were 12 exotic weeds, including Taraxacum officinale, Rumex crispus, and Trifolium repens. Additionally, according to Braun-Blanquet's scale showed that the dominance value was level 1 (41.98% and 46.43%, respectively) in two surveys. Currently, 40% of the total surveyed peach orchards applied herbicides for weed control. These results could provide basic data to assist orchardists in selecting the most suitable weed management methods; thereby, reducing labor inputs and effectively lowering costs while improving fruit yields in peach orchards of Korea.

Weed Flora and Management Practices in Peach Orchard Fields in Korea

WeiQiang Jia,황기선,원옥재,이인용,이정란,노석원,박기웅 한국잔디학회 2017 Weed & Turfgrass Science Vol.6 No.2

This study was carried out two surveys in 2015 to monitor weed occurrence and determine the most troublesome weeds in peach orchards of Korea. The first survey identified 56 taxa belonging to 23 families including 27 annuals, 11 biennials, and 18 perennials. Based on importance values, Conyza canadensis (5.12%), Plantago asiatica (4.17%), and Trifolium repens (3.86%) were the dominant weeds in the first survey (from April to June). Seventeen exotic weeds were identified in the first survey, including Conyza canadensis, Trifolium repens, and Chenopodium ficifolium. The second survey (from September to October) identified 42 weeds belonging to 19 families including 23 annuals, 5 biennials, and 14 perennials. According to importance values, Digitaria ciliaris (8.00%) was the most dominant weed, followed by Echinochloa utilis (6.61%) and Rorippa palustris (6.48%). There were 12 exotic weeds, including Taraxacum officinale, Rumex crispus, and Trifolium repens. Additionally, according to Braun-Blanquet’s scale showed that the dominance value was level 1 (41.98% and 46.43%, respectively) in two surveys. Currently, 40% of the total surveyed peach orchards applied herbicides for weed control. These results could provide basic data to assist orchardists in selecting the most suitable weed management methods; thereby, reducing labor inputs and effectively lowering costs while improving fruit yields in peach orchards of Korea.

Differential Growth Response of Acetolactate Synthase Inhibitors-resistant Sagittaria trifolia Originated from Seeds and Tubers

WeiQiang Jia,Sug-Won Roh,Sung Hwan Choi,Jong Chan Won,Soo Yong Shim,Jung-Sung Chung,Le Thi Hien,Aung Bo Bo,Kee Woong Park,Jeung Joo Lee 한국잡초학회·한국잔디학회 2021 Weed & Turfgrass Science Vol.10 No.1

Continuous use of acetolactate synthase (ALS) inhibitors has led to the selection of herbicide-resistant Sagittaria trifolia in paddy fields. Herbicide-resistant (R) S. trifolia was first reported in 2011 in Korea. The objective of this study was to investigate the level and mechanism of resistance and understand the fitness of R biotypes using R and susceptible (S) S. trifolia biotypes originated from seeds and tubers. Whole plant dose-response showed that the R biotypes originated from tubers were highly resistant to cyclosulfamuron and moderately resistant to penoxsulam and imazaquin, with R/S ratios of 250, 13 and 8, respectively. Compared to the S biotype, the R biotype originated from tuber had an amino acid substitution at the position of a Pro197-Leu residue of als gene, a well-known mutation site that could confer resistance to sulfonylurea, triazolopyrimidine, and imidazolinone herbicides. Additionally, the germination rate and growth of the S biotypes originated from seeds were lower than those of the R biotypes. The growth of the S biotypes originated from tubers was more vigorous than that of the R biotypes. Once the seed of R biotypes move to uninfected paddy fields, the germination rate of R biotypes is probably more than that of existing S biotypes. If ALS inhibitors are applied into paddy fields, R biotypes can survive and even produce tubers that can continually propagate and probably become dominant in the population in uninfected paddy fields. Thus, increasing the application rate of ALS inhibitors to kill R biotypes probably can enhance ALS-inhibitors’ selection-pressure.

Evaluation of Three in-season Tests for Rapidly Detecting Resistance to Acetolactate Synthase Inhibitors in Schoenoplectus juncoides

WeiQiang Jia,Sug-Won Roh,Jae Eun Song,Aung Bo Bo,Kwang Min Cho,Kee Woong Park,Jeung Joo Lee 한국잡초학회·한국잔디학회 2021 Weed & Turfgrass Science Vol.10 No.1

Schoenoplectus juncoides is a noxious weed in paddy field of Korea. The excessive and unreasonable use of acetolactate synthase (ALS)-inhibiting herbicide caused the evolution of herbicide-resistant S. juncoides. As a part of the management of ALS-inhibiting herbicide resistance, early detection of the ALS-inhibiting herbicide resistance in S. juncoides is necessary. In this study, we evaluated three methods of rapidly detecting ALS-resistance in S. juncoides, including the cutting root test, cutting shoot test, and resistance in-season quick (RISQ) test. Three herbicide-resistant populations of S. juncoides (GR, 217R, and WR) and one susceptible population of S. juncoides (HS) collected from the Chungcheongnam-do and Jeollabuk-do of Korea served as experimental materials for the evaluation of three resistance test methods established by previous studies. In the three test methods, the GR and 217R were confirmed as resistant to flucetosulfuron and susceptible to penoxsulam. The WR was highly resistant to flucetosulfuron and penoxsulam. All the three resistance test methods have been successfully applied for identifying the ALS-inhibiting herbicide-resistant S. juncoides in-season. Especially, the result of cutting roots test demonstrated that the GR, 217R, and WR biotypes were highly resistant to flucetosulfuron with the R/S ratios of 34, 100, and 1852, respectively based on GR50. The WR biotype was highly resistant to penoxsulam with the R/S ratio of 912, whereas the GR and 217R biotypes were susceptible to penoxsulam. These in-season quick tests are likely to contribute to the use of effective herbicide in crops leading to decreased costs of labour and inputs in paddy field, and increased profits.

In situ deposition of flower-like ZnO on silk fibroin fibers

Xu, Jia,Su, Huilan,Han, Jie,Chen, Ying,Song, Weiqiang,Gu, Yu,Moon, Won-Jin,Zhang, Di Springer-Verlag 2012 APPLIED PHYSICS A MATERIALS SCIENCE AND PROCESSING Vol.108 No.1

A Review on the Status of Exotic Weed (Chenopodium album L.) in Korea and Methods to Control

레티현,WeiQiang Jia,조광민,Botir Khaitov,박기웅 한국잔디학회 2019 Weed & Turfgrass Science Vol.8 No.3

Intensive globalization of markets, rises of tourism and exchange of goods have facilitated intentional and unintentional movement of plant species beyond natural geographical barriers. These activities led to the distribution of unwanted plant species in all parts of the world, as well as in Korea. Chenopodium album L. known by many common names fat hen, white goosefoot, and common lamb’s quarters weeds, and belongs to the Chenopodiaceae family and originated from Europe. It is a widespread and troublesome weed in agricultural areas throughout the north temperate regions of the world. C. album thrives as a common weed in gardens, near streams, rivers, forest clearings, fields, waste land, and disturbed soils. Across the world, C. album is considered as one of the most troublesome weeds due to its impacts on agricultural production. In Korea, C. album is also responsible for yield losses in many important crops but no detail evaluation of its impact has been undertaken yet. Therefore, this review aims at providing an up-to-date and comprehensive appraisal about occurrence and distribution, physiological characteristics, economic damage analysis and management system of C. album.

Mechanisms of glyphosate-resistant horseweed (Conyza canadensis) collected from tangerine orchards in Korea

보보,WeiQiang Jia,Thi Hien Le,원옥재,Botir Khaitov,조광민,박인곤,박기웅 한국원예학회 2021 Horticulture, Environment, and Biotechnology Vol.62 No.6

Chemical control has become less eff ective for the invasive weed species horseweed ( Conyza canadensis ) found in tangerine( Citrus reticulate ) orchards of Korea. The dose–response assays of the biotypes of C. canadensis collected in 2017 fromthe Jeju province of Korea demonstrated that the amount of glyphosate needed for 50% growth reduction (GR 50 ) in theglyphosate-resistant (GR) biotype was up to 100 times greater than that in the glyphosate-susceptible (GS) biotype (0.328 kga.e. ha −1 ). However, the mechanism of resistance in the GR populations of C. canadensis in Korea is unknown. Therefore,this study aimed to determine the mechanism of resistance to glyphosate in the Korean C. canadensis populations. Shikimicacid accumulation and 5 -enolpyruvyl shikimate- 3 -phosphate synthase ( EPSPS ) gene expression were analyzed in a GR anda GS biotype of C. canadensis. The GR biotype showed less shikimic acid accumulation than the GS biotype. A target pointmutation in the sequence encoding the Pro 106 of EPSPS1 was not found after sequencing the GR biotype. Moreover, theexpression level of EPSPS1 was not altered signifi cantly following application of glyphosate to the GS and GR biotypes,whereas the levels of M10 and M11 ABC transporter genes which play an important role in plant growth and nutrition,and the interaction of the plant with its environment were found to be slightly higher in the glyphosate-treated GS and GRbiotypes than the untreated control plants. Our results show that M10 and M11 are likely to be involved in the glyphosateresistance mechanism in C. canadensis . Consequently, non-chemical control methods should be implemented to manage orslow the spread of glyphosate resistance in C. canadensis.

Persistence, Viability and Emergence Rate of Canola (Brassica napus L) in Korean Soil

Mirjalol Umurzokov,WeiQiang Jia,조광민,Botir Khaitov,손수인,조진웅,박기웅 한국잔디학회 2019 Weed & Turfgrass Science Vol.8 No.4

Estimation of seed persistence, viability and identifi cation of emergence of canola seeds by depth of burial in the soil were the main purposes of this study. One hundred canola seeds were buried at 5, 25, and 30 cm depth of the soil in April and July 2018 at the confined field trials of Chungnam National University, Daejeon, South Korea. Eight removal dates were replicated three times. Burial seeds were exhumed and then intact seeds were tested for germination at monthly intervals. The viability of non-germinated intact seeds was determined by tetrazolium test. The seeds, which were buried at 30 cm depth, could persist longer than the seeds had been buried at 5 and 25 cm. As seeds were buried longer period, intact and dormant seeds were less and deteriorated seeds were more. With regard to emergence of canola, seeds were seeded at diff erent depth of soil and recorded its emergence rate 21 and 28 days after seeding under glasshouse and field conditions respectively. The greatest number was observed when seeds were at 1 cm depth. Seeds did not emerge beyond 13 and 11 cm depth of soil under glasshouse and fi eld conditions respectively. The results of this study will also be useful for future studies of biology and ecology of transgenic canola. However, the persistence of viable canola seeds in Korea is barely understood and further research is needed.

Current status and agronomic aspects of herbicide resistance in Korea

보보,정인호,원옥재,WeiQiang Jia,윤혜진,Botir Khaitov,Thi Hien Le,Mirjalol Umurzokov,Farrukh Ruziev,임민주,조광민,박기웅,이증주 충남대학교 농업과학연구소 2019 Korean Journal of Agricultural Science Vol.46 No.2

Weeds are a serious problem in crop production. Use of synthetic herbicides is rapidly increasing in weed management worldwide including Korea. Herbicide application reduces the time spent on weed control. However, the evolution of resistance to herbicides in weeds has become widespread as a natural response to selection pressure imposed by agricultural management activities. If an herbicide with the same mechanisms of action is used repeatedly and intensively, it can rapidly select for a weed biotype that shifts toward difficult-to-control becoming a more tolerant weed and lead to the evolution of herbicide-resistant weeds. Moreover, agricultural and biological factors have an important role in the development of herbicide-resistant weed populations. Mitigating the evolution of herbicide resistance in weeds relies on reducing selection through the diversification of weed control techniques. The resistance management of weeds in the future will strongly depend on intensive cropping systems. The current situation of intensive cropping systems with their heavy reliance on the efficacy of chemical weed control will not lead to significant containment of this problem. Therefore, management strategies need to overcome the further spread of herbicide resistance in weeds in Korean crop production. This review presents the current information on herbicide resistance in Korea and factors controlling the development of herbicide resistant weeds.