Jeollabuk do Agricultural Research and Extension Services

Iksan, South Korea

Jeollabuk do Agricultural Research and Extension Services

Iksan, South Korea
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Han G.S.,Gangneung - Wonju National University | Kim B.S.,Gangneung - Wonju National University | Choi I.Y.,Jeollabuk do Agricultural Research and Extension Services
Plant Disease | Year: 2016

Homalocladium platycladum (F. Muell. ex Hook.) L.H. Bailey [syn. Muehlenbeckia platyclada (F. Muell.) Meisn.], commonly known as centipede plant or ribbonbush, is a plant in the Polygonaceae from New Guinea and the Solomon Islands. In Korea, this plant is grown in greenhouses for ornamental purposes. In October 2015, several plants were found damaged by a powdery mildew in a greenhouse in Gongju (36°26′ N; 127°14′ E), Korea. In January 2016, powdery mildew symptoms were found on H. platycladum plants grown in a greenhouse in Seocheon (35°01′ N; 126°43′ E), Korea. Symptoms first appeared as thin white patches on the upper surface of leaves, which progressed to abundant hyphal growth on the both side of the leaves. Infected leaves, especially infected when young, often turned yellow or chlorotic with twisted margins and resulted in early defoliation. Voucher specimens were deposited in the Korea University Herbarium (KUS-F19990, F29116, F29129). Hyphal appressoria were well-developed, lobed, and solitary or in opposite pairs. Conidiophores were cylindrical, 70 to 160 × 7.5 to 9.0 µm, and composed of 3 to 4 cells. Foot-cells of conidiophores were straight, cylindric, and 25 to 40 µm long. Singly produced conidia were cylindric-oval to oblong, 30 to 47 × 15 to 25 µm with a length/width ratio of 1.3 to 2.3, with angular/rectangular wrinkling of outer walls, and devoid of distinct fibrosin bodies. Germ tubes were produced in the perihilar position of conidia. No chasmothecia were found. These structures are typical of the powdery mildew Pseudoidium anamorph of the genus Erysiphe. The measurements and host range match with those of E. polygoni DC. (Braun and Cook 2012). The complete internal transcribed spacer (ITS) regions of KUS-F29116 were amplified with primers ITS5/P3 and sequenced (Takamatsu et al. 2009). The resulting 558 bp sequence was deposited in GenBank (accession no. KX098506). The ITS sequence showed >99% sequence identity with the sequences of E. polygoni on Polygonum spp. (LC010013, AB104522, AF011307, etc.). Pathogenicity was confirmed through inoculation by dusting conidia onto leaves of five healthy potted H. platycladum. Five noninoculated plants served as controls. Inoculated plants were isolated from noninoculated plants in separate rooms in a greenhouse maintained at 26 to 30°C. Inoculated plants developed symptoms after 6 days, whereas the controls remained symptomless. The fungus present on the inoculated plants was identical morphologically to that originally observed on diseased plants, fulfilling Koch’s postulates. Association of H. platycladum with E. polygoni has been known in the United States, Europe (United Kingdom, Czech Republic, Romania, Finland, and former Soviet Union), and Asia (China, Taiwan, Nepal, and India) (Lebeda et al. 2007; Farr and Rossman 2016). To our knowledge, this is the first report of powdery mildew caused by E. polygoni on H. platycladum in Korea. Our observations in two greenhouses showed that this powdery mildew expanded rapidly on young leaves and detracted from the aesthetic value of plants. © 2016, American Phytopathological Society. All rights reserved.


Cho S.E.,Korea University | Zhao T.T.,Korea University | Choi I.Y.,Jeollabuk do Agricultural Research and Extension Services | Shin H.D.,Korea University
Plant Disease | Year: 2017

Catharanthus roseus (L.) G. Don [Apocynaceae], known as Madagascar periwinkle, is popularly planted in gardens and parks for ornamental purposes globally. In September 2015, individuals of pot-grown C. roseus were found infected with a powdery mildew in a nursery in Seoul, Korea. Numerous chasmothecia were formed on the lesions by November. Two voucher specimens were deposited in the Korea University Herbarium (KUS-F29106 and F29108). The hyphal appressoria were well-developed, multilobed or moderately lobed, and positioned singly or in opposite pairs. Conidiophores were straight, 80 to 140 × 7 to 9 µm, and composed of 3 to 4 cells. Foot-cells of conidiophores were straight or slightly sinuous at the base and 40 to 70 µm long. Singly produced conidia were oblong-elliptical, 34 to 55 × 15 to 20 µm with a length/width ratio of 1.6 to 2.6, devoid of distinct fibrosin bodies, and showed angular/rectangular wrinkling of outer walls. Germ tubes were produced in the perihilar position of the conidia. Chasmothecia were amphigenous, 85 to 120 μm in diameter, and contained 4 to 7 asci. Peridium cells of chasmothecia were irregularly polygonal and 15 to 25 µm wide. Appendages were mycelioid, 1- to 4-septate, brown at the base and becoming paler. Asci were ellipsoid to obovoid, short stalked, and 45 to 60 × 30 to 40 μm. Ascospores numbered 3 to 5 were ellipsoidal, 20 to 25 × 11 to 14 μm. The morphological characteristics were consistent with previous records of Erysiphe aquilegiae var. ranunculi (Grev.) R.Y. Zheng & G.Q. Chen (Braun and Cook 2012). To confirm the identification, the complete internal transcribed spacer (ITS) regions of KUS-F29106 were amplified with primers ITS1/ITS4, and sequenced directly. The resulting 684-bp sequence was deposited in GenBank (accession no. KX979915). A GenBank BLAST search of the Korean isolate showed >99% similarity with E. aquilegiae var. ranunculi (e.g., AB015929, AF154322). Pathogenicity was confirmed through inoculation tests by pressing a diseased leaf onto young leaves of three asymptomatic, potted plants. Three noninoculated plants were used as controls. Plants were maintained in a greenhouse at 24 to 30°C. Inoculated leaves developed symptoms after 5 days, whereas the controls remained symptomless. The fungus on the inoculated leaves was identical morphologically to that observed on the original diseased leaves. Powdery mildews of C. roseus have been recorded as Leveillula taurica, Oidium sp., and Erysiphe sp. (Amano 1986; Watanabe and Sato 2009; Farr and Rossman 2016). Liberato and Cunnington (2006) reported E. aquilegiae as a powdery mildew of C. roseus, and Braun and Cook (2012) listed the fungus as E. aquilegiae var. ranunculi. To our knowledge, this is the first report of powdery mildew caused by E. aquilegiae var. ranunculi on C. roseus in Korea. Since infected, symptomatic plants may cause loss in sale of nursery plants and market value, control strategies should be followed. © The American Phytopathological Society.


Kim K.M.,Chonbuk National University | Won G.Y.,Chonbuk National University | Choi I.Y.,Jeollabuk do Agricultural Research and Extension Services
Plant Disease | Year: 2016

Marsh mallow (Althaea officinalis L.) belongs to family Malvaceae and is used both as a medicinal and ornamental plant (Shah et al. 2011). During winter 2013 and 2014, marsh mallow grown in a plastic greenhouse in Gongju (36°29′42.2″ N; 127°02′00.8″ E), Korea, exhibited typical signs and symptoms of Sclerotinia stem rot. The lower stems near soil level developed a brown rot. Leaves on rotted stems became chlorotic and wilted. Dark brown stem lesions enlarged and white cottony mycelial mats covered the affected area, followed by crown rot and wilt a few days afterward. About 10% of plants died before harvest due to the disease. Whitish aggregates of mycelia developed into sclerotia that were 2 to 8 mm in diameter outside and inside affected stems. Stem tissues were surface-disinfested with 1% sodium hypochlorite, and segments were transferred onto potato dextrose agar (PDA). Resultant colonies were white or light gray and floccose, with black sclerotia (5 to 10 mm in diameter) on the surface near colony margin. A representative isolate was deposited in the Korean Agricultural Culture Collection (Accession No. KACC47725) and used for pathogenicity tests and molecular analysis. Based on the morphology and culture characteristics, the fungus was identified as Sclerotinia sclerotiorum (Lib.) de Bary (Mordue and Holliday 1976). Fungal DNA was extracted with a DNeasy Plant Mini Kit (Qiagen Inc., Valencia, CA). The internal transcribed spacer region of rDNA was amplified using primers ITS1/ITS4 and sequenced. The resulting 558-bp sequence was deposited in GenBank (Accession No. KJ614566). A BLASTn search revealed that sequences of the Korean isolates shared 100% identity to several isolates of S. sclerotiorum (e.g., KJ614564, JN013184, KF859932, and DQ329537). Pathogenicity tests were conducted by placing PDA plugs (9 mm2) from a 7-day-old culture on the stems of three healthy plants at the soil line. Three plants inoculated with noncolonized PDA plugs served as controls. Plants were enclosed in plastic bags that were sprayed with water on the inside to maintain high humidity and kept in a greenhouse at 16 to 20°C. After 3 days, all inoculated stems became discolored, soft, watery, and covered with white mycelia, whereas control plants remained symptomless. Sclerotinia sclerotiorum was consistently reisolated from the symptomatic tissue, fulfilling Koch’s postulates. Pathogenicity tests were repeated twice with similar results. Sclerotinia stem rot of A. officinalis has never been recorded globally, though crown rot of A. rosea caused by S. sclerotiorum has been reported in the North America (Farr and Rossman 2015). To our knowledge, this is the first report of Sclerotinia stem rot on A. officinalis in Korea. Our continuous observations during winter season (December, January, and February) suggest that low temperature at night, high humidity, poor ventilation, and continuous cultivation in nonheated plastic greenhouse cultivation systems can increase the incidence and severity of Sclerotinia stem rot on marsh mallow plants. © 2016, American Phytopathological Society. All rights reserved.


Cho S.E.,Korea University | Hong S.H.,Korea University | Choi I.Y.,Jeollabuk do Agricultural Research and Extension Services | Shin H.D.,Korea University
Plant Disease | Year: 2017

Ajuga reptans L. (Lamiaceae), known as bugle or bugleherb, is a perennial herbaceous plant native to Europe. Though invasive in parts of North America, it is an ornamental commonly grown as a ground cover in temperate climates. In September 2015, hundreds of A. reptans individuals of an unknown cultivar grown in a public garden (34°47′40″ N; 126°22′25″ E) in Mokpo, Korea, were found damaged by a powdery mildew with approximately 50% disease incidence. Symptoms first appeared as white colonies, which subsequently covered both sides of leaves, detracting from the aesthetic value of affected plants. Chasmothecia were abundantly formed by November. Voucher specimens (KUS-F29062, F29224) were deposited in the Korea University Herbarium (KUS). The hyphae were septate, branched, and 3 to 8 μm in width. Conidiophores (n= 20) were straight, 130 to 200 × 10 to 12 μm, and produced 2 to 5 immature conidia in chains with a crenate outline. Foot-cells of conidiophores were straight, cylindric, and 35 to 95 μm long. Conidia (n= 20) were hyaline, ellipsoid-ovoid to barrel-shaped, 24 to 33 × 21 to 27 μm with a length/width ratio of 1.1 to 1.5, and contained distinct fibrosin bodies. Dark brown chasmothecia were scattered to gregarious, spherical, and 75 to 95 µm in diameter. Peridium cells were polygonal to irregular, 15 to 32 μm diam. Appendages were few, mycelioid, 1- to 5-septate, 5 to 9 μm wide, brown at the base and becoming paler upwards. Each chasmothecium contained a single ascus. Asci with a terminal oculus of 10 to 15 µm wide were sessile, broadly ellipsoid-ovoid to subglobose, 8-spored, and 65 to 92 × 47 to 58 μm. Ascospores (n= 20) were colorless, ellipsoidal, and 15.0 to 22.5 × 12.5 to 16.5 µm. These characteristics were consistent with those of Podosphaera elsholtziae(Z.Y. Zhao) T.Z. Liu & U. Braun (Braun and Cook 2012). The internal transcribed spacer (ITS) region of isolate KUS-F29062 was amplified using universal primers ITS1/ITS4 and sequenced (White et al. 1990). The obtained ITS sequence was deposited in GenBank (accession no. KX668270). A GenBank BLAST search of the Korean isolate showed 100% identity with P. elsholtziaeon A. reptans from Japan (AB026142). Pathogenicity was confirmed by pressing a diseased leaf onto young leaves of three healthy, potted A.reptans. Three noninoculated plants served as controls. Plants were maintained in a greenhouse at 24 to 30°C. The first lesions developed on leaves of inoculated plants after 7 days, whereas the control plants remained symptomless. There have been two previous records of powdery mildew infection caused by Podosphaera spp. on A.reptansfrom Italy and Japan; P. fuscafrom Italy (cf.Braun 1995) andP. elsholtziae from Japan (Ito and Takamatsu 2010). To our knowledge, this is the first report of powdery mildew caused by P. elsholtziae on A.reptansin Korea. Due to shade tolerance and growth habit in dense mats, A. reptansis preferred to be planted as ground cover under trees. Therefore, powdery mildew seems to be inevitable. Breeding of resistant varieties is urgently necessary. © The American Phytopathological Society.


Hong K.-J.,Plant and Fisheries Quarantine and Inspection Agency | Yu D.,Jeollabuk Do Agricultural Research and Extension Services | Park S.,Seoul National University
Journal of Asia-Pacific Entomology | Year: 2012

The host plant, Schisandra chinensis (Turcz.) Baill. (Schisandraceae), of the weevil Dendrobaris maculata (Roelofs) (Madarini) is reported for the first time. The larvae grow in the lower stem of S. chinensis at the soil surface. Host plants are up to 5. years old. Redescription, photos of habitus, and genitalia of the weevil and damage and biological data of the host plant are provided. © 2011 Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society.


PubMed | National Institute of Horticultural and Herbal Science, Korea University, Jeollabuk do Agricultural Research and Extension Services and Chonbuk National University
Type: Journal Article | Journal: Mycobiology | Year: 2016

Extensive disease surveys performed during the summers of 2013 and 2014 in Schisandra chinensis orchards resulted in the finding of a Septobasidium sp. associated with felt disease. The fungus was characterized to be symbiotic with a scale insect (Pseudaulacaspis cockerelli). Morphological and molecular characteristics of the Septobasidium isolates were investigated. The isolates were morphologically and phylogenetically close to S. bogoriense. We tentatively describe this isolate as a Septobasidium sp., mainly because of the limited amount of information available on the internal transcribed spacer region of the ribosomal DNA of Septobasidium spp.


Sharma P.K.,Jeollabuk do Agricultural Research and Extension Services | Sharma S.K.,Indian Central Soil Salinity Research Institute | Choi I.Y.,Jeollabuk do Agricultural Research and Extension Services
Physiology and Molecular Biology of Plants | Year: 2010

Response of wheat genotype HD 2329 to individual and combined effects of alkalinity and waterlogging (WL) at tillering, panicle emergence and anthesis stage was studied. Both stresses increased Na accumulation and reduced K uptake which leads to higher Na+/K+ ratio in the leaves. Yield was decreased under all the stress treatments and highly correlated with Na+/K+ ratio at all the three growth stages (r = -0.83, -0.82 and -0.73, respectively) with maximum reduction under pH 9.4 + WL. Increase in pH from 7.2 to 9.1 and 9.4 delayed complete panicle emergence (4 and 8 days) and flowering (1 and 2 days) at both, tillering and panicle emergence stages. Dual stress further increased days, required for complete panicle emergence and flowering. These results suggested that high Na+/K+ ratio of plant tissue may be the critical factor for growth and development of wheat under WL, alkalinity and dual stress. Due to this delay in flowering and panicle emergence, times required for maturity of grains shorten, resulted in lower grain yield. © 2010 Prof. H.S. Srivastava Foundation for Science and Society.


Lee J.-H.,Chonbuk National University | Ahn B.-K.,Jeollabuk do Agricultural Research and Extension Services
Communications in Soil Science and Plant Analysis | Year: 2010

Applicability of various chemical extracts was investigated as quantity (Q) factors to determine cadmium (Cd), zinc (Zn), and copper (Cu) desorption quantity-intensity (Q/I) relationships in soils. The metal extracts were sums of sequential metal fractions (except the residual fraction) using Tessier's (TSE) and Community Bureau of Reference (BCR) procedures and various single chemical extracts: 1.0 M potassium nitrate (KNO3), 1.0 M magnesium nitrate [Mg(NO3)2], 1.0 M magnesium chloride (MgCl2), and 0.11 M acetic acid (CH3COOH) solutions. Water-extractable metal was applied as a fixed intensity (I) factor. The TSE or BCR metal fractions were significantly correlated with diethylenetriaminepentaacetic acid (DTPA)-extractable metals, and all the metal desorption Q/I curves were linearly fitted. However, most of metal BC values estimated by using the single chemical extracts were very low and did not have consistent trends for target metals. Only 0.11 M CH3COOH-extractable metals might be reliable. Therefore, TSE and BCR metal fractions can be applicable to replace DTPA-extractable metals, and 0.11 M CH3COOH-extractable metals might also be useful. © Taylor & Francis Group, LLC.


Lee J.-H.,Chonbuk National University | Kim D.-J.,Chonbuk National University | Ahn B.-K.,Jeollabuk do Agricultural Research and Extension Services
Bulletin of Environmental Contamination and Toxicology | Year: 2015

The objectives of this study were to investigate the distribution of thallium in soils collected near suspected areas such as cement plants, active and closed mines, and smelters and to examine the extraction of thallium in the soils using 19 single chemical and sequential chemical extraction procedures. Thallium concentrations in soils near cement plants were distributed between 1.20 and 12.91 mg kg-1. However, soils near mines and smelters contained relatively low thallium concentrations ranging from 0.18 to 1.09 mg kg-1. Thallium extractability with 19 single chemical extractants from selected soils near cement plants ranged from 0.10 % to 8.20 % of the total thallium concentration. In particular, 1.0 M NH4Cl, 1.0 M (NH4)2SO4, and 1.0 M CH3COONH4 extracted more thallium than other extractants. Sequential fractionation results of thallium from different soils such as industrially and artificially contaminated soils varied with the soil properties, especially soil pH and the duration of thallium contamination. © 2015 Springer Science+Business Media New York.


Lee J.-J.,Jeollabuk do Agricultural Research and Extension Services | Hwang J.-H.,Jeollabuk do Agricultural Research and Extension Services
Korean Journal of Horticultural Science and Technology | Year: 2014

The aim of this study was to determine the effect of day-length extension treatment using LED lighting (blue, green, red, or 3 mixed) on vegetative growth and flowering of freesia ‘Yvonne’, in comparison to that using glow lamps and metal halide lamps. Lighting treatments were imposed from 5 PM to 8 PM for 150 days from after flower bud differentiation to flowering end. For the period from leaf emergence to floral bud formation, no light source affected plant height but the number of leaves was decreased by the metal halide lamp. The highest SPAD value in the flower bud developing period occurred in the metal halide lamp treatment. The time of flowering was advanced by blue or green LED treatment compared to the no lighting control. The green LED lighting advanced flowering by 6 and 8 days compared to no lighting and metal halide lamp treatment, respectively. The blooming period tended to be shortened by the red LED treatment. As for the flower characteristics of ‘Yvonne’, floret length and width, and the weight of cut flowers were highest in the metal halide lamp treatment. Red LED decreased corm width and weight of ‘Yvonne’ while glow lamp decreased height and weight. Starch contents in corm were not influenced by the lighting source. Our results indicate that the green LED lighting advanced the time of flowering and the metal halide lamp was good for cut-flower quality. © 2014 Korean Society for Horticultural Science.

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