• Mycobiology
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• 제39권3호
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• pp.230-232
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• 2011

In this study, we characterized sporadically occurring sclerotium rot caused by Sclerotium rolfsii in Chinese chive (Allium tuberosum Roth.) in farm fields in Sacheon, Korea. The initial symptom of the disease was water-soaked, which progressed to rotting, wilting, blighting, and eventually death. Further, mycelial mats spread over the lesions near the soil line, and sclerotia formed on the scaly stem and leaves. The sclerotia were globoid, 1~3 mm, and white to brown. The optimum temperature for growth and sclerotia formation on potato dextrose agar (PDA) was $30^{\circ}C$. The diameter of the hypae ranged from 4 to 8 ${\mu}m$. Clamp connection was observed on PDA medium after 5 days of incubation. Based on the mycological characteristics, internal transcribed spacer sequence analysis, and pathogenicity test, the causal agent was identified as Sclerotium rolfsii Saccardo. This is the first report of sclerotium rot in Chinese chive caused by S. rolfsii in Korea.

• Mycobiology
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• 제29권3호
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• pp.154-159
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• 2001

Natural sclerotium formation in two species of Curvularia was observed. The sclerotia were spherical to elongated. The scanning electron microscopical observations of sclerotia revealed that the sclerotia were of two distinct layers of cells, outer loosely woven hyphae and inner contact layer of cells. Different lights, viz. red, blue, green, fluorescent or addition of culture filtrate of Sclerotium rolfsii in the medium did not affect sclerotium formation.

• Mycobiology
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• 제38권2호
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• pp.156-158
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• 2010

Stem rot disease was found in garlic (Allium sativum L.) cultivated from 2008 to 2010 in the vegetable gardens of some farmers in Geumsan-myon, Jinju City, Gyeongnam province in Korea. The initial symptoms of the disease were typical water-soaked spots, which progressed to rotting, wilting, blighting, and eventually death. White mycelial mats had spread over the lesions near the soil line, and sclerotia had formed over the mycelial mats on the stem. The sclerotia were globoid in shape, 1~3 mm in size, and tan to brown in color. The optimum temperature for growth and sclerotia formation on potato dextrose agar (PDA) medium was $30^{\circ}C$. The diameter of the hyphae ranged from approximately 4 to $8\;{\mu}m$. Typical clamp connection structures were observed in the hyphae of the fungus, which was grown on PDA medium for 4 days. On the basis of the mycological characteristics and pathogenicity of the fungus on the host plants, the causal agent was identified as Sclerotium rolfsii Saccardo. This is the first report of stem rot disease in garlic caused by S. rolfsii in Korea.

• Mycobiology
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• 제37권2호
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• pp.158-159
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• 2009

In 2007 to 2008, a fruit rot of Melon (Cucumis melo L.) caused by Sclerotium rolfsii occurred sporadically in a farmer's vinyl house in Jinju City. The symptoms started with watersoaking lesion and progressed into the rotting of the surface of fruit. White mycelial mats appeared on the lesion at the surface of the fruit and a number of sclerotia formed on the fruit near the soil line. The sclerotia were globoid in shape, 1${\sim}$3 mm in size, and white to brown in color. The hyphal width was measured 3 to 8 ${\mn}$. The optimum temperature for mycelial growth and sclerotia formation was 30 on PDA. Typical clamp connections were observed in hyphae of grown for 4 days on PDA. On the basis of symptoms, mycological characteristics and pathogenicity to the host plant, this fungus was identified as Sclerotium rolfsii Saccardo. This is the first report of the fruit rot of Melon caused by S. rolfsii in Korea.

• 식물병연구
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• 제11권2호
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• pp.128-134
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• 2005

파속채소에 발생하여 큰 피해를 주는 흑색썩음균핵병균을 대상으로 외국 도입균주와 국내 분리균주간의 유전형을 UP-PCR을 이용하여 Tyson 등이 보고한 방법으로 조사한 결과, 국내에서 분리되는 Sclerotium cepivorum은 UP-PCR그룹 b에 속하는 것으로 확인되었으며, 대균핵 형성균과 DNA profile에 있어서 현저한 차이를 보였다. 두 가지 병원균의 균핵 표면구조를 전자현미경을 이용하여 확인한 결과, S. cepivorum은 대균핵 형성균에 비해 잔주름이 적고 내부에 포자와 유사한 구조가 관찰되었다. 흑색썩음균핵병을 일으키는두 가지 병원균은모두 $10\~25^{\circ}C$에 범위에서 생장되었고 생장 최적온도는 $20^{\circ}C$이었으며, $28^{\circ}C$ 이상에서는 전혀 자라지 않았다. 두 가지 병원균의 균핵 형성정도는 $20^{\circ}C$에서 배양시 가장 높았고 균핵 발아정도는 $20\~24^{\circ}C$ 범위에서 높았다 처리온도를 달리하여 처리일수별로 휴면중인 병원균 균핵의 발아정도를 조사한 결과, $35^{\circ}C$에서 7일간 전처리한 후 $10^{\circ}C$에서 7일간 배양했을 때 발아가 가장 잘 되었으며 S. cepivorum은 $70\%$,대균핵 형성균은 $100\%$발아되었다. 담수기간 및 처리온도가 병원균의 생존에 미치는 영향을 조사한 결과 처리온도가 높아질수록 균핵 발아 정도가 감소되는 것으로 나타났다. 흑색썩음균핵병을 일으키는 두 가지 병원균은 토양습도에 따라 발병정도에 있어서 큰 차이를 보였다. 마늘흑색썩음균핵병은 토양습도가 $15\%$(-300 mb)일 때 가장 높은 발병을 보였으며 $17\%$ 이상되거나 $13\%$ 이하로 되었을 때에는 토양습도가 $15\%$일 때에 비해 병 발생이 현저히 감소되었다.

• 농약과학회지
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• 제19권1호
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• pp.64-70
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• 2015

마늘 흑색썩음균핵병(Sclerotium cepivorum)은 마늘 생산에 큰 영향을 미치는 주요한 토양병으로, 이를 방제하기 위하여 태양열 소독, 균핵발아 유도물질의 사용, 미생물을 이용한 생물적 방제, 살균제 처리 등 다양한 방법이 활용되고 있다. 그 중에서 살균제를 사용하는 방법을 가장 실용성이 높은 방법이다. 본 실험에서는 살균제의 작용기작이 다른 prochloraz (a.i. 25%, EC), tebuconazole (a.i. 25%, WP), flutolanil (a.i. 15%, EC), iminoctadine trisalbesilate (a.i. 40%, WP), isoprothiolane (a.i. 40%, EC) 5종의 살균제를 선정하여 병원균의 균사생장, 균핵발아, 균핵형성에 미치는 영향을 조사하였으며, 마늘 인편 절단법을 사용하여 공시한 살균제의 병 방제효과를 조사하였다. 병원균의 균사생장에 대해서는 prochloraz와 tebuconazole의 효과가 우수하였는데, prochloraz는 $0.8{\mu}g\;mL^{-1}$을, 그리고 tebuconazole은 $100{\mu}g\;mL^{-1}$을 첨가한 PDA 배지에서 병원균이 전혀 생장을 하지 못하였다. 또한 prochloraz는 $10{\mu}g\;mL^{-1}$의 처리구에서, 그리고 tebuconazole은 $1.0{\mu}g\;mL^{-1}$의 처리구에서 발아가 완전히 억제되었다. Isoprothiolane은 균사생장과 균핵발아에 대한 억제효과는 크기 못했지만, $1.67{\mu}g\;mL^{-1}$의 처리구에서 균핵의 형성을 63.5% 억제하였다. 마늘 인편 절단법을 사용하여 병 방제 효과를 조사한 결과, $100{\mu}g\;mL^{-1}$의 처리구에서 prochloraz, tebuconazole, flutolanil 등이 70% 이상의 효과를 보였다.

• Mycobiology
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• 제31권2호
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• pp.105-112
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• 2003

Sclerotia of Grifola umbellata were cultivated by two methods such as burying and root inoculation methods. The sclerotia of G. umbellata produced by the burying method were $6.0{\sim}6.8{\times}3.4{\sim}4.6{\times}1.8{\sim}1.9cm$(Width$\times$Length$\times$Thickness) in size and $17.3{\sim}19.6g$ in weight, respectively. Their increase rate was $1.10{\times}1.12$ times. On the other hand, the sclerotia cultivated by the root inoculation method were $18.3{\sim}31.5{\times}12.5{\sim}26.4{\times}3.1{\sim}3.7cm(W{\times}L{\times}T)$ in size and $219.1{\sim}576.6g$ in weight, respectively. Their growth increment was $11.18{\sim}39.77$ times. The rhizomorphs of Armillaria mellea were developed with a high density under fallen leaves layer covering cultivation site, and distributed mainly between soil surface and soil depth of about 10 cm as well as colonized prominently on the inoculated wood logs. Fungal interaction between G. umbellata and A. mellea were observed mainly in the stage of white sclerotium of G. umbellata. The sclerotia of G. umbellata which were developed newly and harvested in the root inoculation method were twined with root hairs of host tree and rhizomorphs of A. mellea. The sclerotia of G. umbellata decomposing root hairs of host tree were confirmed through SEM examination. Physiochemical characteristics of soil in all cultivation sites had no significant differences. Soil pH were in the range of pH $3.98{\sim}4.40$. Organic matters were the range of $17.97{\sim}23.86%$ and moisture contents of soil were $12.00{\sim}18.20%$. Soil temperatures showed $12.9{\sim}13.8^{\circ}C$ in November and $22.0{\sim}23.9^{\circ}C$ in August, respectively. In conclusion, the root inoculation method seems to be a practical method for cultivating sclerotia of G. umbellata due to its many advantages such as simplicity of inoculation process, shortening of cultivation periods and facility of harvest.

• Mycobiology
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• 제32권1호
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• pp.1-5
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• 2004

The present study was carried out to investigate morphological characteristics of pseudosclerotia of Grifola umbellata formed by artificial cultures. Isolate G. umbellata DUM GUS-01 was obtained from sclerotium cultivated in field. The fungal isolate was cultured on PDYM broth, PDYMA(potato dextrose yeast malt agar) and oak sawdust media at $20^{\circ}C$ under the dark condition. G. umbellata DUM GUS-01 showed a volumetric increment of fungal lumps rather than mycelial growth. Particularly, G. umbellata DUM GUS-01 produced a large amount of melanin pigments in all culture treatments. The color of the fungal mass has been changed into grey gradually, and then formed melanized rind-like structure on its superficial part. The fungal structures which were covered with melanized rind-like layer were named as pseudosclerotia of G. umbellata. The pseudosclerotia of G. umbellata DUM GUS-01 formed a new white mycelial mass, which was swollen out of the melanized rind structure for its volumetric increment. When the pseudosclerotia were sectioned, their structure was discriminated from two structures such as a melanized rind-like structure layer formed by aggregation of aged mycelia and a white mycelial mass with high density. As results of scanning electron microscopic examination, the pseudosclerotia of G. umbellata DUM GUS-01 which were formed in in vitro conditions were similar to the sclerotia of G. umbellata cultivated in natural conditions except for the crystals formed in medula layer of natural sclerotia. Although size, solidity of rind structure and mycelial compactness of pseudosclerotia were more poor than those of natural sclerotia, the morphological structure and growth pattern of pseudosclerotia were very similar to those of natural sclerotia. Therefore, it is probable to induce pseudosclerotia to sclerotia of G. umbellata in in vitro conditions. Consequently, it seems that the induced pseudosclerotia can be used as inoculum sources to substitute natural sclerotia in field cultivation.

• Current Research on Agriculture and Life Sciences
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• 제5권
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• pp.127-133
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• 1987

콩과목초(科牧草) 균핵병균(菌核病菌) S. trifoliorum의 완전세대 형성과정중 수정(受精)의mechanism과 그 시기를 밝히고 균핵(菌核)내부의 해부학적(解剖學的) 구조변화의 양상(樣相)을 실험한 결과는 다음과 같이 요약된다. 본 실험에 공시(供試)한 S계통(系統)의 균주(菌株)에 있어서 수정가능상태(受精可能狀態)에의 도달은 균핵(菌核)을 포화습도(飽和濕度) 15C에 치상(置床)한 후 18일 경인 것으로 밝혀졌으며 수정가능상태(受精可能狀態)는 일부의 균핵(菌核)에서 치상(置床) 후(後) 45일 경까지 지속되는 것으로 나타났다. 본(本) 균(菌)의 균핵(菌核)이 수정가능상태에 달하게 되면 균핵(菌核)의 교배형(交配型)과 관계없이 그 내부에 염색성(染色性)이 강한 균계집단(菌系集團)이 출현하였는데 이들의 진전과정을 homothallic 계통(系統)과 heterothallic 계통(系統)에서 비교 검토한 결과, ascogonium으로 판단할 수 있었다. 이들 ascogonium은 치상 후 약 45일 경까지 지속적으로 관찰되었으나 치상 39일 경부터 퇴화되어 가는 것이 관찰되었다. 균핵내부에서의 ascogonium의 출현 지속기간과 균핵의 수정가능기간이 서로 잘 부합되었다.

• The Plant Pathology Journal
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• 제20권4호
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• pp.240-243
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• 2004

White rot on Allium crops recently had a high incidence with incrensed cultivating areas of tropical garlic types in Korea. Two types of Sclerotium have known as causal agents that produce different size and shapes of sclerotia in infested fields. Therefore, we developed a new method for isolation of sclerotia from infested field soils that can be used for ecological study of Sclerotium spp. and establishment of control strategy. Soil samples collected from heavily infested fields were evenly mixed and placed on a automatic sieve shaker connected with tap water, After 10 min of shaking, residues on 0.5 mm and 0.25 mm sieves were separately collected and suspended with 70% sugar solution, which method floats sclerotia in aqueous layer, Then, floated fraction was carefully separated and mixed with a same volume of 1% sodium hypochlorite solution to differentiate with organic materials. This method provides a direct count of sclerotia under a dissecting microscopy.