• The Korean Journal of Mycology
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• v.29 no.1
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• pp.72-74
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• 2001

A destructive collar rot of water cress (Oenanthe javanicav) occurred in the commerical farm at Karye-myon, Uiryong-gun, Kyongsangnam-do in 2000. The causal fungus caused stem rot, crown rot, wilt or blight of water cress and the disease incidence in 3 fields ranged from 28.6 to 42.8%. White mycelia spread over tissues near the soil surface or stems, and sclerotia developed on the lesions at late season. The fungus grew well on PDA at $20^{\circ}C$ and the typical clamp connection was formed on its tough white mycelia $4.1{\sim}10.3{\mu}m$. The fungus also formed white mycelia mats and sclerotia at $20^{\circ}C$ on PDA. The sclerotia were globoid and sized $1.0{\sim}6.3{\times}1.0{\sim}5.2mm$ (av. $2.4{\sim}2.2mm$). The causal fungus of collar rot disease was identified as Sclerotium rolfsii on the basis of mycological characteristics and pathogenicity test, This is the first report on the collar rot of water cress caused by Sclerotium rolfsii in Korea.

• Research in Plant Disease
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• v.30 no.2
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• pp.114-123
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• 2024

In July 2022, stem rot symptom was found in a peony plant grown in a pot under a greenhouse at Jinju, Gyeongnam Province, South Korea. Two fungal species were isolated from the infected peony stems and cultured on 1/2-strength potato dextrose agar for identification. The morphological characteristics of the fungal isolates were examined, and nucleotide sequences of the internal transcribed spacer region, β-tubulin and translation elongation factor 1-α were analysed. The pathogenicity of the two isolates was confirmed in detached peony leaves, according to Koch's postulates. To our knowledge, this is the report of Neopestalotiopsis clavispora and Sclerotinia sclerotiorum as the causal agents of peony stem rots. Antifungal activity of chemical fungicide propineb and rhizobacterium Bacillus siamensis H30-3 was shown against the two plant pathogenic fungi N. clavispora and S. sclerotiorum.Unidentified diffusible and volatile compounds from B. siamensis H30-3 could suppress in vitro mycelial growths of N. clavispora JJ 8-2-1 and S. sclerotiorum JJ 8-2-2.

• The Korean Journal of Mycology
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• v.45 no.4
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• pp.381-385
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• 2017

Sclerotinia rot was observed on Ixeridium dentatum cultivated as a succeeding crop in a garlic field in Seosan-si, Korea during the growing season in 2016 and 2017. Symptoms progressed from the initial irregular, water-soaked spots on main stems to wilting and eventually to plant death. White, cottony mycelia and black, irregular sclerotia formed on the basal stem and on soil surfaces. The optimal temperature of hyphal growth and sclerotia germination were $20^{\circ}C$ and $25^{\circ}C$, respectively. Sequence analysis of the internal transcribed spacer (ITS) regions revealed that the three strains isolated from Ixeridium dentatum are grouped with Sclerotinia sclerotiorum. Three strains were identified as Sclerotinia sclerotiorum based on morphological features, ITS sequence, and pathogenicity test. To the best of our knowledge, this work is the first report of Sclerotinia sclerotiorum causing sclerotinia rot on Ixeridium dentatum in Korea.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.676-681
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• 1998

Disease incidence of Codonopsis lanceolata was surveyed at the major cultivating fields in Chonbuk province in 1996 to 1997. The main diseases of Codonopsis lanceolata were ovserved as leaf spot caused by Septoria codonopsis, anthracnose by Glomerella cingulata, brown leaf spot by Cercospora sp., rust by Coleosporium koreanum, powdery mildew by Erysiphe sp., Fusarium wilt caused by Fusarium oxyporum, and white root rot by Sclerotium rolfsii. Anthracnose, leaf spot and brown leaf spot occurred severely on leaves from early July to late August. They were caused early fallen leaves. Fusarium wilt and white root rot occurred severely on stem and below the soil line in late August. They resulted in withering to death or chlorosis and fallen of leaves. Disease incidence of Codonopsis lanceolata was also substantially different in occurrence with a method of cultivation in late growth stage. Fusarium wilt and white root rot were more severe with a method of no support cultivation than those with a method of support cultivation with a stick. Fusarium wilt occurred 48.8% in a method of no support cultivation but 3.1% in a method of support cultivation with a stick. And white root rot occurred 18.9% in a method of no support cultivation but 0.3% in a method of no support cultivation with a stick. Thus, it proved that soil-borne diseases could be controlled support cultivation with a stick.

• Research in Plant Disease
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• v.30 no.1
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• pp.88-94
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• 2024

In July 2021, symptoms of soft rot were observed on the stems of Ficus carica in Yeongam, Jeollanamdo, Korea. To accurately diagnose the cause, infected stem was collected and bacterial strain was isolated. Among these, the pathogenic strain KNUB-08-21 was identified as Pectobacterium aroidearum through 16S rRNA gene sequencing and phylogenetic analysis based on the concatenated sequences of the dnaX, leuS, and recA genes. The affiliation of the isolate with this bacterial species was also confirmed by its biochemical characteristics obtained using API ID 32 GN system. Artificial inoculation confirmed the strain's pathogenicity in figs, causing significant damage to both stems and fruits. To our knowledge, this is the first report of P. aroidearum causing soft rot disease in F. carica in Korea.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2002.11a
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• pp.100.2-101
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• 2002

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2000.10a
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• pp.44.1-44
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• 2000

• Research in Plant Disease
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• v.23 no.1
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• pp.56-59
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• 2017

During growing season of 2011 to 2013, Sclerotinia rot symptoms consistently have been observed on basil in Yesan-gun, Chungcheongnam-do in Korea. The typical symptom formed initially brownish spot on leaf and stem, and then advancing margins, wilting the whole plant and blighting, eventually died. On the surface of diseased lesions was observed cottony, white, dense mat of mycelial growth, and sclerotia ($30-100{\mu}m$ diameter) formed on stem and leaf. Morphological and cultural characteristic on potato dextrose agar, color of colony was white and colorless chocolate, sclerotium of irregular shape of the oval was black and $5-50{\mu}m$ diameter in size. In pathogenicity test, necrosis and wilt of the inoculated stem were observed in all plants and the pathogen was reisolated from stems. On the basis of mycological characteristics, pathogenicity, and internal transcribed spacer rDNA sequence analysis, this fungus was identified as Sclerotinia sclerotiorum. This is the first report of Sclerotinia rot on basil caused by S. sclerotiorum in Korea.

• Journal of Microbiology and Biotechnology
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• v.24 no.10
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• pp.1327-1336
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• 2014

Bacillus amyloliquefaciens strain NJZJSB3 has shown antagonism of several phytopathogens in vitro, especially Sclerotinia sclerotiorum. Both the broth culture and cell suspension of strain NJZJSB3 could completely protect the detached leaves of canola (Brassica napus) from S. sclerotiorum infection. In pot experiments, the application of strain NJZJSB3 cell suspension ($10^8CFU/ml$) decreased the disease incidence by 83.3%, a result similar to commercially available fungicide (Dimetachlone). In order to investigate the potential biocontrol mechanisms of strain NJZJSB3, the nonvolatile antifungal compounds it produces were identified as iturin homologs using HPLC-ESI-MS. Antifungal volatile organic compounds were identified by gas chromatography-mass spectrometry. The detected volatiles toluene, phenol, and benzothiazole showed antifungal effects against S. sclerotiorum in chemical control experiments. Strain NJZJSB3 also produced biofilm, siderophores and cell-wall-degrading enzymes (protease and ${\beta}$-1,3-glucanase). These results suggest that strain NJZJSB3 can be a tremendous potential agent for the biological control of sclerotinia stem rot.

• The Korean Journal of Mycology
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• v.29 no.2
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• pp.131-133
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• 2001

A destructive collar rot disease was found on broad bean (Vicia faba) in several farmer's field located in Changseon-myon, Namhae-gun, Gyeongsangnam-do in 2001. The typical symptoms of the disease were stem rot, crown rot, wilt or blight. Upper parts of the infected stems were mostly blighted and white mycelial mats were spread over lesions and the sclerotia were formed on the stems near soil line. The infection rates of the disease in the surveyed area were ranged from 28.6 to 42.8%. The sclerotia of the fungus readily formed in artificial media such as PDA at $30^{\circ}C$ and its shape was globoid or irregular and size was $1.0{\sim}3.7{\times}1.0{\sim}2.8\;mm\;(av.\;1.0{\sim}2.3\;mm)$ and was brown or dark brown in color. The optimum temperature for growth of the fungus was about $30^{\circ}C$. The typical clamp connections were found in the hypha of the fungus grown on PDA. On the basis of mycological characteristics and pathogenecity test on host plants, the fungus was identified as Sclerotium rolfsii. This is the first report on the collar rot of broad bean caused by Sclerotium rolfsii in Korea.