• The Plant Pathology Journal
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• 제29권4호
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• pp.440-445
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• 2013

Balloon flower (Platycodon grandiflorum) is a kind of mountain herbs whose roots have restorative properties and the cultivating acreage of balloon flower has been steadily increasing in Korea. More frequent rain and high amount of rainfalls as a result of climate changes predisposed balloon flower to the outbreaks of root rot at high-density cultivation area in recent years. Root crowns were usually discolored into brown to blackish brown at first and the infected plants showed slight wilting symptom at early infection stage. Severely infected roots were entirely rotted and whole plants eventually died at late infection stage. The overall disease severities of root rot of balloon flower were quite variable according to the surveyed fields in Jeonnam, Gyeongnam and Jeju Provinces, which ranged from 0.1% to 40%. The root rot occurred more severely at the paddy or clay soils than the sandy soils and their severities were much higher at lowland than upland in the same localty. The disease increased with aging of the balloon flower. The causal fungi were identified as Fusarium solani and F. oxysporum on the basis of their mycological characteristics. The optimum temperature ranges of their mycelial growths was found to be $24^{\circ}C$. The pathogenic characters of F. solani and F. oxysporum treated by artificial wounding inoculation on healthy roots of balloon flower revealed that F. solani was more virulent than F. oxysporum. This study identified the causal agents of root rot of balloon flower as Fusarium solani and F. oxysporum, probably for the first time.

• Mycobiology
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• 제29권4호
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• pp.224-226
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• 2001

Inflorescence of Allium thunbergii was found to be severely infected with Fusarium sp. The flower was covered with the fungus and eventually failed to form seeds. The causal fungus was identified as F. proliferatum(Matsushima) Nirenberg based on the cultural and morphological characteristics. Pathogenicity of the fungus was proved by artificial inoculation onto the healthy plants. This is the first record of this disease from Korea.

• The Plant Pathology Journal
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• 제28권2호
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• pp.156-163
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• 2012

Stem rots caused by Rhizoctonia solani and Sclerotinia sclerotiorum have been known as devastating diseases in balloon flower plants. Antifungal activities of four fungicides, azoxystrobin, polyoxin B, trifloxystrobin and validamycin A were evaluated in vitro, showing effective suppression with mycelial growth of the fungal isolates on PDA media. Efficacies of the four fungicides were also demonstrated in stem tissues of balloon flower plants against R. solani and S. sclerotiorum. A commercially available Bacillus subtilis strain Y1336 was tested in terms of antagonistic biological control of stem rot disease of balloon flower plants. The bacterial strain revealed its antifungal activities against R. solani and S. sclerotiorum demonstrated by dual culture tests using paper discs and two plant pathogenic fungi on PDA media, as well as by plant inoculation assay, indicating that this antagonistic bacterial strain can be incorporated into disease management program for balloon flower stem rot diseases together with the four chemical fungicides.

• Journal of Microbiology and Biotechnology
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• 제10권4호
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• pp.435-440
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• 2000

A pathogenic fungus causing balloon flower root rot (Platycodon grandiflorum) was isolated from naturally infected roots. The microbial characteristics of the isolated microorganism were similar to those of Rhizoctonia solani. About 500 bacterial species from field soils were screened for a biological agent against the above-mentioned putative pathogen, and several bacteria with the antifungal activity were isolated. Among them, the isolated JS2 was identified as Pseudomonas aeruginosa. This strain showed a broad spectrum of antifungal activity potentially. When the antifungal substance was purified from a broth culture of JS2, it was identified as 2,4-diacetylphloroglucinol (Phl).

• The Plant Pathology Journal
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• 제16권6호
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• pp.321-324
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• 2000

season of 2000. The disease infection usually started from flower, peduncle and young fruits, then moved to flower stalk, stem and leaves. At first, the lesions started with water-soaked, rapidly softened, and then the area gradually expanded. In severely affected film house, the rate of infected fruits reached to 28.6%. Numerous sporangiospores were formed on the diseased fruits, flower stalk, stem and leaves. Most of the sporangiospores were appeare to be rapidly dispersed in the air. The mycelia grew on the surface of host and formed stolons. Colonies on potato dextrose agar were cottony at first brownish black at maturity. Sporangia were 125.3${\times}$294.2 ${\mu}$m. globose or sub-globose with somewhat flattened base. White at first the black, many spored, and are never overhanging. Sporangiophores were 2.7-6.8${\times}$12.9-33.9 ${\mu}$m, smooth-walled, non-septate, light brown, simple, long, arising in groups of 3-5 from stolons opposite rhizoids. Sporangiophores were 8.6-21.1${\times}$6.41-1.7 ${\mu}$m, irregular, round, oval, elongate, angular and brownish-black streaked. Columella were 63.8${\times}$140.4 ${\mu}$m. brownish gray, umberella-shaped when dehisced. The causal organism was identified as Rhizopus stolonifer Lind on the basis of the morphological characteristics of the fungus. Rhizopus soft rot on squash (Cucurbita moschata) caused by the fungi has not been previously reported in Korea.

• 원예과학기술지
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• 제19권4호
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• pp.591-595
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• 2001

'Casablanca'와 'Marco Polo' 품종의 구근 저장중 발생하는 부패병을 방제하기 위해 azoxystrobin, benomyl+thiram 및 prochloraz와 길항세균배양액 등을 처리하여 적정 약제 및 농도를 구명하고, 약제처리된 구근의 생육상 및 절화의 품질을 조사하여 약해의 유무를 판별하고자 수행하였다. 백합구근이 부패병 발생은 azoxystrobin과 prochloraz가 억제 효과가 있으며, Benomyl+thiram는 국내산 구근의 부패병 발병 억제 효과가 없는 것으로 조사되었다. 생리적으로 백합구근의 견고성을 증가시키기 위해 처리한 calcium chloride 혼용처리는 부패병을 증가시켰다. 길항세균 배양액을 1/5로 희석하여 처리하였을 때, 부패병이 발생을 효과적으로 억제하였다. 재배중 'Casablanca' 품종은 benomyl+thiram 처리구에서, 'Marco Polo' 품종은 benomyl+thiram와 calcium 혼용 처리구에서 맹아 억제가 심하였다. 구근의 저장전 약제처리는 백합의 영양생장 과정에서 생육상과 꽃의 품질에는 영향을 주지 않으며, calcium과 benomyl+thiram 처리구에서 잎과 꽃의 길이가 다른 처리구에 비해 작으나 유의차는 없었다.

• 식물병연구
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• 제21권4호
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• pp.334-336
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• 2015

2013년 7월 경상남도 진주시농업기술센터 양묘장 전시포에 재배중인 할미꽃에서 흰비단병 증상이 발생하였다. 병징은 할미꽃의 꽃줄기와 꽃자루 부분이 수침상으로 물러지면서 부패되어지고 서서히 시들면서 포기 전체가 말라 죽었다. 병반부와 토양 표면에 흰색의 곰팡이가 발생하며 갈색의 작은 둥근 균핵이 많이 형성되었다. 감자한천배지에서 균총은 흰색이고 배양 기간이 경과됨에 따라 갈색의 작은 둥근 균핵을 많이 형성하였다. 균핵의 크기는 1-3 mm이며 균사의 폭은 $4-9{\mu}m$였다. 균사생육과 균핵 형성 적온은 $30^{\circ}C$이었다. 균사특유의 clamp connection이 관찰되었다. 할미꽃에서 발생한 병징과 병원균의 균학적 특징, 그리고 ITS rDNA 염기서열 비교분석 결과, 이 병을 S. rolfsii Saccardo에 의한 할미꽃 흰비단병으로 명명하고자 제안한다.

• 식물병연구
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• 제8권1호
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• pp.55-58
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• 2002

2001년 진주시 도로변 정원에서 Choanephora cucurbitarum에 의한 부용 꽃썩음병이 발생하였다. 병징은 처음 꽃잎부분이 수침상으로 물려지면서 부패하고 급속히 진전되어 썩었다 PDA또는 병반부위에서 균사는 처음 흰색에서 연한 노란색이며 검은색의 포자낭을 형성되고 백색의 균사가 아주 많이 형성되었다. 단포자성포자는 갈색이고 단포로서 방추형, 타원형 또는 난형이며 크기는 12.3~21.6 $\times$8.3~11.6$\mu$m였다. 포자낭은 대부분 구형이고 크기는 42.6-114.2$\mu$m였다. 포자낭포자는 갈색이고 단포로서 방추형 , 타원형 또는 난형이며 크기는 16.3~23.8$\times$8.2~13.6$\mu$m였다. 양쪽 글에 3개에서 수개의 부속사를 형성하였다. 접합포자는 구형의 검은색이고 크기는 46.2-78.4$\mu$m였다. 균사생육 적온은 3$0^{\circ}C$였다. 이상과 같이 병원균의 균학적 특징과 병원성을 검정한 결과 이 병을 Choanephora cucurbitarum에 의한 부용 꽃썩음병으로 명명할 것을 제안하고자 한다.

• 식물병연구
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• 제9권1호
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• pp.25-27
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• 2003

2002년 경상남도 진주시 도로변 화단에 재배중인 팬지에서 줄기가 수침상으로 물러지고 부패하는 증상이 관찰되었다. 이 병의 병징은 지제부가 암갈색으로 변하고 그위에 흰색의 곰팡이가 솜털처럼 밀생하며, 병반 부위뿐만 아니라 지제부의 토양 표면에도 갈색의 둥근 균핵이 많이 형성된다. 병원균의 균사생장 및 균핵형성은 PDA배지에 배양시 3$0^{\circ}C$에서 가장 양호하였다. 균사에는 특유의 clamp connection이 관찰되었고 균사 폭은 3.9~10.4 $\mu\textrm{m}$이었다. 균핵은 갈색 또는 암갈색으로 크기는 1.3~4.2 mm 이었다. 이상의 특징으로 이 병원균은 Sclerorium rolfsii로 동정하였으며 팬지 흰비단병으로 명명할 것을 제안한다.

• The Plant Pathology Journal
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• 제17권4호
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• pp.231-235
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• 2001

From April to May 1998, Phytophthora rot on pear, which has not been reported in Korea before, became an epidemic in the southeast part of the country under abnormally higher temperature and prolonged rainy days. Average temperature was about $3^{\circ}$ higher than in normal years, and 29 days were rainy during the 2 months in the areas surveyed. Over 1,000 orchards estimated at about 270 ha in 19 cultivation areas were infected by the disease, which occurred on all parts of the tree such as leaves, shoots, branches, stems, and flower clusters. Among 43 isolates collected from various locations and plant parts, 41 were identified as Phytophthora cactorum while 2 were identified as P. cambivora based on their mycological characteristics. The representative isolates revealed strong pathogenicity not only to pear but also to apple and peach. Among 23 pear cultivars tested, 7 were estimated as susceptible, 4 were moderate, and 11 were resistant to the pathogen. Results suggest that Phytophthora disease on pear is a potential threat to pear cultivation when environmental factors are favorable to disease development.