• Title/Summary/Keyword: stem rot.

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Sclerotium Rot of Cowpea (Vigna sinensis King) Caused by Sclerotium rolfsii (Sclerotium rolfsii에 의한 동부 흰비단병)

  • Kwon, Jin-Hyeuk;Kang, Dong-Wan;Han, Inyoung;Choi, Yong-Jo;Lee, Sang-Dae;Son, Daeyoung
    • The Korean Journal of Mycology
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    • v.44 no.1
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    • pp.61-63
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    • 2016
  • Sclerotium rot disease on cowpea (Vigna sinensis King) was observed in the exhibition field of Gyeongsangnam-do Agricultural Research and Extension Services in September 2015. Lesions were covered by white mycelial mats, and numerous 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 mycelial growth and sclerotia formation on potato dextrose agar (PDA) was $30^{\circ}C$, with the hyphal width of $4{\sim}8{\mu}m$. For molecular identification, the complete internal transcribed spacer (ITS) rDNA region of the causal fungus was sequenced and analyzed. Based on the mycological characteristics, ITS rDNA sequence analysis, and pathogenicity test, this fungus was identified as Sclerotium rolfsii. This is the first report of sclerotium rot on cowpea caused by S. rolfsii in Korea.

Sclerotium Rot of Onion Caused by Sclerotium rolfsii (Sclerotium rolfsii에 의한 양파 흰비단병)

  • Kwon, Jin-Hyeuk;Kim, Hee-Dae;Choi, Ok-Hee;Kwak, Youn-Sig;Lee, Yong-Hwan;Shim, Hong-Sik
    • Research in Plant Disease
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    • v.17 no.2
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    • pp.222-224
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    • 2011
  • The sclerotium rot of onion (Allium cepa L.) was occurred sporadically in the farmer's fields at Daehap, Changnyeong in Korea. The typical symptom was water-soaking on the bulb, stem and leaves and then rotting, wilting, blighting and the infected plants eventually were rotted and died. The sclerotia were globoid, 1-3 mm, and white to brown. The optimum temperature for mycelial growth and sclerotial formation on PDA was $30^{\circ}C$. The hyphal width was 4-9 ${\mu}m$. The typical clamp connections were observed in the hyphae of the fungus grown on PDA. On the basis of mycological characteristics, ITS rDNA sequence analysis, and pathogenicity, this fungus was identified as Sclerotium rolfsii Saccardo. To our knowledges, this is the first report of sclerotium rot on onion caused by S. rolfsii in Korea.

Sclerotinia Rot of Broad Bean (Vicia faba) Caused by Sclerotinia sclerotiorum (Sclerotinia sclerotiorum에 의한 잠두 균핵병)

  • Kwon, Jin-Hyeuk;Bae, Yeoung-Seuk
    • Research in Plant Disease
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    • v.13 no.2
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    • pp.115-118
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    • 2007
  • Sclerotinia rot occurred on the stem and pod of broad bean (Vicia faba) at Gyeongsangnam-do Agricultural Research and Extension Services in Korea from 2004 to 2006. The infected plants showed the typical symptoms; wilted, water-soaked, rotted and eventually died. The colony of the isolated fungus on PDA was white to faintly gray color. Apothecia were cup-shaped and $5{\sim}10\;mm$ in size. Asci were cylindrical in shape and $90{\sim}180{\times}8{\sim}12\;{\mu}m$ in size. Ascospores were ellipsoid and $8{\sim}12{\times}4{\sim}6\;{\mu}m$ in size. Sclerotia formed on the PDA were globose to cylindrical or irregular in shape with black color. The optimum temperature for mycelial growth was $25^{\circ}C$ and sclerotia formation was at $20^{\circ}C$ on PDA. This is the first report on sclerotinia rot of broad bean (Vicia faba) caused by Sclerotinia sclerotiorum (Lib.) do Bary in Korea.

Sclerotium rolfsii Causing Collar Rot on Doonggulle (Polygonatum odoratum var. pluriflorum) (둥굴레에 흰비단병을 일으키는 Sclerotium rolfsii에 관하여)

  • Kwon, Jin-Hyeuk;Kang, Soo-Woong;Park, Chang-Seuk
    • The Korean Journal of Mycology
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    • v.28 no.2
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    • pp.121-122
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    • 2000
  • A destructive collar rot of Doonggulle (Polygonatum odoratum var. pluriflorum) occurred in an experimental farm at Hamyang Medicinal Plant Experiment Station, Kyonguam ARES in 1999. The disease also observed in farmer's fileds in Hamyang and the infection rate reached up to 12.3%. Upper parts of the infected plants were mostly blighted and white mycelial mats were formed on the lesions or soil lines near the stem. The fungus readily formed sclerotia on PDA and then shapes were globoid or irregular, and sized $0.9{\sim}6.8{\times}0.6{\sim}5.2\;mm$ (av. $2.7{\sim}2.3\;mm$). Although the fungus showed wide range of mycelial growth temperature, the optimum temperature was about $30^{\circ}C$. The typical sclerotium type and clamp connections of hyphae were found in the fungus grown in PDA. The causal fungus was identified as Sclerotium rolfsii on the basis of mycological characteristics and pathogenicity that on the host plants. This is the first report on the collar rot of Polygonatum odoratum caused by Sclerotium rolfsii in Korea.

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Occurrence of Sclerotium Rot of Corn Caused by Sclerotium rolfsii in Korea (Sclerotium rolfsii에 의한 옥수수 흰비단병 발생)

  • Kwon, Jin-Hyeuk;Kang, Dong-Wan;Lee, Heung-Su;Choi, Si-Lim;Lee, Sang-Dae;Cho, Hyeoun-Suk
    • The Korean Journal of Mycology
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    • v.41 no.3
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    • pp.197-199
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    • 2013
  • The sclerotium rot of corn (Zea mays L.) occurred sporadically at the experimental field of Gyeongsangnam-do Agricultural Research and Extension Services in July 2011. The infected stems were water-soaked, wilted, and finally led to the death of the whole plants. White mycelial mats were spread over lesions, and then sclerotia were formed on stem and near soil line. The sclerotia were globoid in shape, white to brown in color and 1-3 mm in size. The hyphal width was $4-8{\mu}m$. The optimum temperature for mycelial growth and sclerotia formation on PDA was 30 on PDA. The typical clamp connections were observed in the hyphae of the fungus grown on PDA. On the basis of mycological characteristics and pathogenicity to host plants, this fungus was identified as Sclerotium rolfsii Saccardo. This is the first report of sclerotium rot on corn caused by S. rolfsii in Korea.

Sclerotinia Rot of Fatsia japonica Caused by Sclerotinia sclerotiorum (Sclerotinia sclerotiorum에 의한 팔손이 균핵병)

  • Kwon Jin-Hyeuk
    • Research in Plant Disease
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    • v.12 no.2
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    • pp.122-124
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    • 2006
  • Sclerotinia rot was occurred on the leaf and stem of Fatsia japonica in Geoje city, Gyeongnam province in Korea from 2004 to 2005. The typical symptom of the disease was water-soaked infected leaves and stems. The colony of the isolated fungus was white to faintly gray in color. Apothecia were cup-shaped with numerous asci and $0.8{\sim}1.3 cm$ in size. Asci were cylindrical in shape and $70{\sim}220{\times}4{\sim}18{\mu}m$ in size. Ascospores were aseptate, hyaline, ellipsoid in shape, and $6{\sim}12{\times}4{\sim}6{\mu}m$ in size. Sclerotia formed on the plants and PDA medium were globose to cylindrical or irregular in shape, black in color. The optimum temperature for mycelial growth was $25^{\circ}C$. This is the first report on the Sclerotinia rot of Fatsia japonica caused by Sclerotinia sclerotiorum in Korea.

Sclerotinia Rot of Peucedanum japonicum Thunb. Caused by Sclerotinia sclerotiorum (Sclerotinia sclerotiorum에 의한 갯기름나물 균핵병 발생)

  • Jung, Won-Kwon;Lim, Yang-Sook;Kim, Min-Ki;Kim, Jong-Su
    • Research in Plant Disease
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    • v.27 no.3
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    • pp.115-119
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    • 2021
  • Sclerotinia rot was occurred on the leaf and stem of Peucedanum japonicum Thunb. in greenhouse field of Pohang city of Gyeongbuk province in Korea. The typical symptom of the disease was light brown spot and tipburn on infected leaves. The colony of the isolated fungus was white to light gray in color. Asci were cylindrical shape and 75-240×5.9-17.3 ㎛ in size. Apothecia were cup-shaped with numerous asci and 0.5-0.9 cm in size. Ascospores were aseptate and ellipsoid in shape, and 8.4-10.7×4.8-5.8 ㎛ in size. Sclerotia formed on the plants and potato dextrose agar medium were globose to irregular in shape and black in color. Partial sequencing of rDNA of this isolate showed that it was 100% consistent with that of Sclerotinia sclerotiorum. It was confirmed that the same lesion was formed by reinoculating this pathogen on a healthy P. japonicum Thunb. and the same strain was isolated. This is the first report on the Sclerotinia rot of P. japonicum Thunb. caused by S. sclerotiorum in Korea.

Evaluation of Durum Wheat Genotypes for Resistance against Root Rot Disease Caused by Moroccan Fusarium culmorum Isolates

  • Bouarda, Jamila;Bassi, Filippo M.;Wallwork, Hugh;Benchacho, Mohammed;Labhilili, Mustapha;Maafa, Ilyass;El Aissami, Aicha;Bentata, Fatiha
    • The Plant Pathology Journal
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    • v.38 no.1
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    • pp.1-11
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    • 2022
  • Fusarium culmorum is one of the most important causal agents of root rot of wheat. In this study, 10 F. culmorum isolates were collected from farms located in five agro-ecological regions of Morocco. These were used to challenge 20 durum wheat genotypes via artificial inoculation of plant roots under controlled conditions. The isolate virulence was determined by three traits (roots browning index, stem browning index, and severity of root rot). An alpha-lattice design with three replicates was used, and the resulting ANOVA revealed a significant (P < 0.01) effect of isolate (I), genotype (G), and G × I interaction. A total of four response types were observed (R, MR, MS, and S) revealing that different genes in both the pathogen and the host were activated in 53% of interactions. Most genotypes were susceptible to eight or more isolates, while the Moroccan cultivar Marouan was reported resistant to three isolates and moderately resistant to three others. Similarly, the Australian breeding line SSD1479-117 was reported resistant to two isolates and moderately resistant to four others. The ICARDA elites Icaverve, Berghisyr, Berghisyr2, Amina, and Icaverve2 were identified as moderately resistant. Principal component analysis based on the genotypes responses defined two major clusters and two sub-clusters for the 10 F. culmorum isolates. Isolate Fc9 collected in Khemis Zemamra was the most virulent while isolate Fc3 collected in Haj-Kaddour was the least virulent. This work provides initial results for the discovery of differential reactions between the durum lines and isolates and the identification of novel sources of resistance.