• Korean Journal Plant Pathology
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• v.14 no.2
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• pp.184-185
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• 1998

Rhizoctonia stem rot of Saururui herba [Saururus chinensis (Lour) Baill] was observed during plantations from 1996 to 1997 in Chungbuk area. Infected plant showed damping-off and stem rot at soil line. The causal fungus of stem rot isolated from the infected plant was identified as Rhizoctonia solani according to the criteria based on the cultural and morphological characteristics. The stem rot of Saururi herba caused by Rhizoctonia solani was first described in Korea, and the name the“Rhizoctonia black stem rot”is proposed.

• Research in Plant Disease
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• v.29 no.4
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• pp.377-383
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• 2023

In 2020 and 2021, we surveyed diseases of three-leaf ladybell (Adenophora triphylla) plants grown in fields at two locations in Korea. During the disease surveys, severe leaf rot symptoms were observed on the young plants in Hongseong, and stem rot symptoms on the adult plants in Cheolwon. The incidence of leaf rot was 5-60%, and that of stem rot 1-10%. We obtained 6 fungal isolates each from the leaf rot lesions and the stem rot lesions. All the isolates were morphologically identified as Rhizoctonia solani. Anastomosis test and investigation of cultural features of the fungal isolates revealed that the isolates from the leaf rot lesions corresponded to R. solani AG-1(IB), and those from the stem rot lesions to R. solani AG-2-2(IIIB). Two isolates each of R. solani AG-1(IB) and AG-2-2(IIIB) were used for DNA sequence analysis and pathogenicity test to three-leaf ladybell plants through artificial inoculation. The anastomosis groups and cultural types of the R. solani isolates were confirmed by the sequence analysis. The pathogenicity tests revealed that the isolates of R. solani AG-1(IB) caused only leaf rot symptoms on the inoculated plants, and those of R. solani AG-2-2(IIIB) leaf rot and stem rot symptoms. The induced symptoms were similar to those observed in the fields investigated. Leaf and stem rot of three-leaf ladybell caused by the two anastomosis groups and cultural types of R. solani is first reported in this study.

• Mycobiology
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• v.42 no.4
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• pp.409-411
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• 2014

In March 2014, a kohlrabi stem rot sample was collected from the cold storage room of Daegwallyong Horticultural Cooperative, Korea. White and fuzzy mycelial growth was observed on the stem, symptomatic of stem rot disease. The pathogen was isolated from the infected stem and cultured on potato dextrose agar for further fungal morphological observation and to confirm its pathogenicity, according to Koch's postulates. Morphological data, pathogenicity test results, and rDNA sequences of internal transcribed spacer regions (ITS 1 and 4) showed that the postharvest stem rot of kohlrabi was caused by Sclerotinia sclerotiorum. This is the first report of postharvest stem rot of kohlrabi in Korea.

• The Korean Journal of Mycology
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• v.50 no.1
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• pp.61-64
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• 2022

In July and September 2020, a severe outbreak of stem rot was observed on bonnet bellflower (Codonopsis lanceolata) plants in a farm located in Chuncheon, Gangwon Province, Korea. The symptoms initially appeared on the stem at or above the soil line. Later, the infected stem completely rotted and blighted. The incidence of diseased plants in the field was 2-30%. Ten isolates of Rhizoctonia sp. were obtained from the stem lesions of diseased plants. All isolates were identified as Rhizoctonia solani AG-4 based on the morphological characteristics and anastomosis test. Three isolates of R. solani AG-4 were tested for pathogenicity on bonnet bellflower plants through artificial inoculation. All tested isolates induced stem rot symptoms on the inoculated plants. The symptoms were similar to those observed in plants from the farm. This is the first report of R. solani AG-4 causing stem rot in bonnet bellflower.

• Mycobiology
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• v.51 no.5
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• pp.313-319
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• 2023

During disease surveys of Angelica acutiloba plants in Korea, leaf spot symptoms were observed in a field in Andong in July 2019, and stem rot symptoms in vinyl greenhouses in Yangpyeong in April 2020. Incidence of leaf spot and stem rot of the plants ranged from 10 to 20% and 5 to 30%, respectively. Morphological and cultural characteristics of fungal isolates from the leaf spot and stem rot symptoms fitted into those of the genus Phoma. Molecular phylogenetic analyses of two single-spore isolates from the symptoms using concatenated sequences of LSU, ITS, TUB2, and RPB2 genes authenticated an independent cluster from other Didymella (anamorph: Phoma) species. Moreover, the isolates showed different morphological and cultural characteristics in comparison to closely related Didymella species. These discoveries confirmed the novelty of the isolates. Pathogenicity of the novel Didymella species isolates was substantiated on leaves and stems of A. acutiloba through artificial inoculation. Thus, this study reveals that Didymella acutilobae sp. nov. causes leaf spot and stem rot in Angelica acutiloba.

• The Plant Pathology Journal
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• v.23 no.3
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• pp.212-214
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• 2007

In 2005 and 2007, a basal stem rot of Disporum smilacinum caused by Sclerotium rolfsii occurred sporadically in a herb farm at Hamyang, Korea. The symptom initiated with water-soaking lesion and progressed into stem rot and wilt of a whole plant. Severely infected plants were blighted and died eventually. White mycelial mats appeared on the lesion at early stage and a number of sclerotia were formed on the stem near the soil line. The sclerotia were globoid in shape, 1-3 mm in size and white to brown in color. The optimum temperature for the growth and sclerotia formation was 30 on PDA and the hyphal width was measured $3-8{\mu}m$. The typical clamp connections were observed in the hyphae of the fungus grown on PDA. On the basis of symptom, mycological characteristics and pathogenicity to the host plant, this fungus was identified as Sclerotium rolfsii Saccardo. This is the first report on the stem rot of D. smilacinum caused by S. rolfsii in Korea.

• The Plant Pathology Journal
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• v.18 no.1
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• pp.54-55
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• 2002

Soaked black rot symptom was observed on the stem of Angelica acutiloba from July to August 2000 at Kumsan, Chungnam in Korea. This disease usually occurred under humid and high temperature conditions. The lesions on the stem appeared as soft rot with brown elliptical spots, which developed into large black spots at a later stage. When the bacterial isolates from the diseased plants were inoculated onto healthy plants by artificial needle prick method, symptoms similar to that observed in the fields developed. According to the cultural characteristics and pathogenicity of the isolates on the host plant the causal bacterium was identified as Xanthomonas campestris. This study proposed that the disease be named "bacterial black stem rot of A. acutiloba"loba".

• Mycobiology
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• v.30 no.4
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• pp.244-246
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• 2002

A destructive stem rot of tomato(Lycopersicon esculentum) occurred sporadically some farmers' fields in Jinju City, Gyeongnam province in Korea. The infected plants also showed stem, crown rot or whole plant blight. White mycelium spread over stems of infected plants and formed sclerotia on the old lesions nearby soil surface. The fungus showed maximum mycelial growth around $30^{\circ}C$. The fungus formed white colony on PDA, usually with many narrow mycelial strands in the aerial mycelium and the width were $4.0{\sim}9.8{\mu}m$. The typical clamp connections were formed on the mycelium. Numerous sclerotia was formed on PDA at $30^{\circ}C$. The shape of sclerotia was globoid and $1.0{\sim}3.0$ mm in size. The fungus was isolated repeatedly from the infected tissues and the pathogenicity was confirmed to tomato and identified as Sclerotium rolfsii. This is the first report on the stem rot of tomato caused by S. rolfsii in Korea.

• The Plant Pathology Journal
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• v.20 no.2
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• pp.103-105
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• 2004

A destructive stem rot of strawberry (Fragaria x ananassa cv. Akihime) sporadically occurred in farmers' fields in Daegok-myon, Jinju city, Gyeongnam province in Korea. The infected plants showed stem and crown rot, with occasional blighting of the whole plant. White mycelia appeared on stems of infected clones and sclerotia formed on the old lesions near soil surface. The fungus formed white colony on PDA and showed maximum mycelial growth and sclerotial formation at $30^{\circ}C$. The fungus usually have many narrow hyphal strands, 2.6-10.0 $\mu\textrm{m}$ in width, in the aerial mycelium. Typical clamp connections were formed on the mycelium. Sclerotia were spherical and 1.0-2.4 mm in size. The fungus was repeatedly isolated from infected tissues and identified as Sclerotium rolfsii. Its patho-genicity was confirmed when inoculated onto straw-berry. This is the first report on the stem rot of strawberry caused by S. rolfsii in Korea.

• Research in Plant Disease
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• v.28 no.2
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• pp.108-111
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• 2022

In December 2020, stem and leaf rot symptoms in small-fruited tomato (Solanum lycopersicum) plants were observed in a farmer's vinyl greenhouse located in Pyeongtaek, Gyeonggi Province, Korea. The incidence of diseased plants in the vinyl greenhouse was 2-6%. Seven single-spore isolates of Phoma sp. were obtained from the diseased stems and leaves. All the isolates were identified as Boeremia linicola based on the cultural, morphological and molecular characteristics. Two isolates of B. linicola were tested for pathogenicity on stems and leaves of small-fruited tomato and large-fruited tomato using artificial inoculation. All the tested isolates caused stem and leaf rot symptoms in the inoculated plants. The symptoms were similar to those observed in plants from the vinyl greenhouse investigated. This is the first report of B. linicola causing stem and leaf rot in tomato.