• 한국식물병리학회지
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• 제10권3호
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• pp.169-174
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• 1994

A new unidentified pear leaf spot disease presumed to first occur in the late 1970's has recently become prevalent over the pear growing areas, and caused the greatest problem for pear production in Korea. The disease began to develop on pear leaves at mid- to late May, peaked at mid- to late une, but stopped further development until September in cool climate. Leaf lesions are 0.9∼2.5 mm in diam., oval or irregular to rectangular in shape, first appeared reddish purple, later changed to dark brown, and to whitish grey in the late season. Lesions were limited to appear only on the mature, hardened leaves, initially from leaf margin or near the leaf veins, and later scattered over the leaf surface. Individual lesions usually did not enlarge, but often coalesced each other, commonly causing shot holes and eventual early falling. The disease was most severe on the major pear cultivars Niitaka and Okusankichi ranged with 4 to 100% infections in trees, depending on the orchards, but not on the cultivar Chojuro. Damages from the disease included lower fruit weight, and higher acid and less sugar content in fruits, resulting in lowering the overall fruit quality. Etiology of the disease including identification of the causal organism is in a separate paper.

• Mycobiology
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• 제42권4호
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• pp.405-408
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• 2014

Leaf spot disease was observed in sesame (Sesamum indicum L.) during 2009 and 2010 in Korea. The pathogen was identified as Alternaria simsimi based on morphological and cultural characteristics. The morphological identification was well supported by phylogenetic analysis of the ribosomal DNA-internal transcribed spacer region. A. simsimi isolates caused spot symptoms on leaves and stems of sesame plants 2 wk after artificial inoculation, which were similar to those observed in the field. This is the first record of leaf spot disease in Korea caused by A. simsimi.

• 식물병연구
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• 제27권3호
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• pp.107-114
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• 2021

During a disease survey on weeds and minor cultivated crops in Korea, a brown leaf spot disease was observed on Sonchus asper. Leaf lesions were round or irregular in shape, and grayish brown to brown with a purple margin. In severe infection, lesions enlarged and coalesced, resulting in blighting of the leaves. The isolates from these leaf lesions were identified as Alternaira sonchi based on morphological characteristics and phylogenetic analyses of Internal transcribed spacer region, Alternaria allergen a1, glyceraldehyde 3-phosphate dehydrogenase, RNA polymerase II, and translation elongation factor genes. This study provides a comprehensive description of the morphological characteristics and phylogenetical traits of A. sonchi causing brown leaf spot on S. asper in Korea.

• 한국식물병리학회지
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• 제3권4호
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• pp.285-290
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• 1987

대두 갈색무늬병의 진전은 한 식물체에서 상위엽으로의 진전속도(수직감염율 : vertical progress)과 밀접한 관계가 있다. 실제로 포장에서의 갈색무늬병 진전은 주로 하위엽에서 발병하기 시작하여 상위엽에 비하여 이병정도가 높은 것이 보통이다. 이러한 현상의 원인을 구명하기 위하여 수행한 본 실험에서 갈색무늬병의 감염율은 잎의 성숙도와 정의 상관을 보였으며 이러한 유엽저항성은 접종원의 분포와는 무관한 것으로 보였다. 또 상위엽의 엽표면일출액 (leaf diffusate)은 병원균 포자발아 및 관계신장의 억제 정도가 하위엽의 일출액에 비하여 높았으며 이러한 경향은 저항성품종에서 더욱 현저하여 엽일출액의 어떤 발아억제물질이 갈색무늬병의 유엽저항성에 관여하는 것으로 추정되었다.

• Mycobiology
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• 제51권6호
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• pp.393-400
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• 2023

During a disease survey in October 2019, leaf spot symptoms with a yellow halo were observed on Korean angelica (Anglica gigas) plants grown in fields in Pyeongchang, Gangwon Province, Korea. Incidence of diseased leaves of the plants in the investigated fields ranged from 10% to 60%. Morphological and cultural characteristics of two single-spore isolates from the leaf lesions indicated that they belonged to the genus Didymella. Molecular phylogenetic analyses using combined sequences of LSU, ITS, TUB2, and RPB2 regions showed distinct clustering of the isolates from other Didymella species. In addition, the morphological and cultural characteristics of the isolates were somewhat different from those of closely related Didymella spp. Therefore, the novelty of the isolates was proved based on the investigations. Pathogenicity of the novel Didymella species isolates was confirmed on leaves of Korean angelica plants via artificial inoculation. This study reveals that Didymella gigantis sp. nov. causes leaf spot in Korean angelica.

• The Plant Pathology Journal
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• 제16권6호
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• pp.325-327
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• 2000

A leaf spot of rye (Secale cereale L.) was observed during the summer 1999 in Korea. A fungus associated with the disease was identified as Bipolaris sorokiniana (Sacc.) Shoem., based on the morphological characteristics of conidia and conidiophores. Pathogenicity of the fungus was proven by artificial inoculation on rye plants. This is the first record of leaf spot on rye caused by B. sorokiniana in Korea.

• Mycobiology
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• 제48권1호
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• pp.70-74
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• 2020

Sinowilsonia henryi is a rare and endangered plant, as well as an endemic species in China. In July 2018, leaf spot and blight disease was observed on S. henryi in Yichang, Hubei, China. A fungus isolated from disease tissues was identified as Gonatobotryum apiculatum based on morphology and sequence analyses of ITS and LSU regions. Phylogenetic analyses indicated that the species belongs to Dothioraceae (Dothideales). Morphologically, the species produced two distinct types of conidia from authentic media, both conidia were described here. Pathogenicity tests showed that the fungus is a pathogen causing leaf spots on S. henryi. This is the first report of leaf spot and blight disease on S. henryi caused by G. apiculatum in China.

• 식물병연구
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• 제21권4호
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• pp.330-333
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• 2015

In June 2013, we collected leaf spot disease samples of Datura metel from Gangneung, Gangwon Province, Korea. The symptoms observed were small circular to oval dark brown spots with irregular in shape or remained circular with concentric rings. We isolated the pathogen from infected leaves and cultured the fungus on potato dextrose agar. We examined the fungus morphologically and confirmed its pathogenicity according to Koch's postulates. The results of morphological examinations, pathogenicity tests, and the rDNA sequences of the internal transcribed spacer regions (ITS1 and ITS4), glycerol-3-phosphate dehydrogenase (G3PDH) and the RNA polymerase II second largest subunit (RPB2) gene sequence revealed that the causal agent was Alternaria tenuissima. To the best of our knowledge, this is the first report of leaf spot of D. metel caused by A. tenuissima in Korea as well as worldwide.

• The Plant Pathology Journal
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• 제20권1호
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• pp.67-74
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• 2004

A complete understanding of the epidemiological factors required for optimum for disease development facilitates the design of effective and reliable screening techniques and also disease prediction models. An attempt was made to study the effects of different temperatures ($15-35^{\circ}C$) and leaf wetness periods (4-24 h) on the development of late leaf spot (LLS) in three groundnut genotypes differing in their susceptibility to LLS infection. Irrespective of the genotype, the disease progress evaluated based on different components of resistance was maximum between $15-20^{\circ}C$ and minimum between $20-25^{\circ}C$. At temperatures $\geq$$30^{\circ}C$, LLS development was insignificant. The overall severity of LLS increased with an increase in the leaf wetness period from 4 h to 12 h a day. Further increase of wetness period to 16 h resulted in a rapid increase in the severity. Thereafter, the disease severity gradually decreased with an increase in the wetness period. The effect of temperature and wetness periods on the individual component of disease quantification was not uniform compared between genotypes with different levels of susceptibility/resistance to LLS infection. The results of this study indicate that temperature and leaf wetness period are critical in late leaf spot screening programs since the expression of disease symptoms measured from disease initiation till defoliation, varied differently in the test genotypes with respect to change in these two parameters.

• 식물병연구
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• 제19권3호
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• pp.196-200
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• 2013

콩 점무늬병이 수량에 미치는 영향을 평가하고 경제적 방제수준을 설정하고자 본 시험을 수행하였다. 점무늬병 발병정도와 주당 협수, 주당 총립수, 주당 총립중, 등숙률, 100립중 및 수량과의 상관계수는 각각 -0.90, -0.90, -0.92, -0.99, -0.90, -0.94로 통계적으로 고도의 유의성을 나타내었다. 콩 점무늬병의 병반면적률이 증가됨에 따라 수량은 반비례하여 감소하였는데, 콩 점무늬병 발병정도(x)에 따른 수량(y) 예측모델을 산출한 결과, 회귀식은 y = -3.7213x + 354.99($R^2$= 0.9047)로 고도의 부의 상관이 있었다. 이 회귀식을 토대로 경제적 피해허용수준은 병반 면적률 3.3%, 경제적 방제수준(ET)은 병반면적율 2.6%로 설정할 수 있었다.