• The Plant Pathology Journal
• /
• 제17권3호
• /
• pp.180-183
• /
• 2001

A corynespora leaf spot of pepper, which has not been reported previously in Korea, occurred severely at the major pepper cultivation area of Chinju, Gyeongnam province in 2001. Infection rate ranged from 48.2 to 84.7% in eight fields surveyed. The causal fungus was identified as Corynespora cassicola based on the following cultural and morphological characteristics. The fungi grew well on potato dextrose agar, showing gray to brown color with cultural age. Conidia formed solitary or catenary were obclavate to cylindrical in shape, and pale olivaceous brown or brown in color. They had 420 pseudoseptate and isthmus, and measured 42.7-197.6 x 9.3-$23.5\mu\textrm{m}$. Septate conidiophores were pale to light brown in color, and measured 116.5-836.0 x 4.2-$11.0\mu\textrm{m}$. Conidia germinated as a bi-polar type. Optimal temperature for mycelial growth and conidial germination was $30^{\circ}$ and 25-$30^{\circ}$, respectively. The fungus showed strong pathogenicity to pepper plant, and the symtoms on pepper by the artificial inoculation were similar to those observed in the field. This is the first report on the corynespora leaf spot on pepper (Capsium annuum) caused by Corynespora cassicola in Korea.

• 한국식물병리학회지
• /
• 제14권1호
• /
• pp.52-61
• /
• 1998

This paper is the fifth report about the fungal diseases of economic resource plants observed newly in Korea. It contains short descriptions on symptoms, occurrence conditions, pathogens, and some phytopathological notes for each of 10 fungal plant diseases. They are identified as leaf spot of Adenophora triphylla var. japonica by Septoria lengyelii, leaf spot of Calystegia soldanella by S. convolvuli, leaf spot of Campanula punctata by S. campanulae, leaf spot of Codonopsis lanceolata by S. codonopsidis, leaf spot of Geum japonicum by s. gei, black spot of Oenanthe javanica by s. oenanthes, leaf spot of Oenothera odorata by S. oenotherae, angular leaf spot of Rehmannia glutinosa by S. digitalis, brown spot of Rubus crataegifolius by s. rubi, and leaf spot of Viola verecunda by S. violae-palustris, respectively.

• 한국식물병리학회지
• /
• 제10권4호
• /
• pp.336-338
• /
• 1994

In 1991, the leaf brown spot of ivy-aureus (Scindapsus aureus) was found in Taejon and Seoul, Korea. The symptoms were appeared as dark-brown spots. The lesions were often surrounded by yellowish halos. These spots were enlarged to circular or elliptical in shape and dark-brown to black in color with slightly elevated in margin and sunken in center. The pathogenic bacteria were isolated from the diseased leaf of ivy-aureus were identified as Erwinia chrysanthemi on the basis of bacterial characteristics therefore, we would like to propose to the name of ivy-aureus disease caused by E. chrysanthemi as“bacterial brown rot of ivy-aureus”hereafter.

• Mycobiology
• /
• 제48권6호
• /
• pp.495-500
• /
• 2020

Leaf spot on lemon balm is frequently observed in Korea, causing considerable damage to crops. In 2014 and 2015, the occurrence of leaf spot was observed in several production greenhouses at Suwon, Gongju, and Namwon in Korea. Symptoms on lower leaves initially developed as small, distinct, discolored lesions, which enlarged progressively turning into dark brown, angular spots surrounded by purplish-brown margins. Based on the morphological characteristics and sequence analysis of actin (ACT), translation elongation factor 1-alpha (EF-1α), internal transcribed spacer (ITS), 28S nrDNA (LSU), and RNA polymerase II second largest subunit (RPB2), the fungus associated with the lemon balm leaf spot was determined as Septoria melissae. To the best of our knowledge, this is the first report of lemon balm leaf spot caused by S. melissae in Asia as well as in Korea.

• Mycobiology
• /
• 제45권2호
• /
• pp.114-118
• /
• 2017

In September 2013 and 2014, a significant number of kenaf plants showing symptoms of leaf spots with approximately 50% incidence were found in experimental plots in Iksan and Namwon, Korea. Leaf spots were circular to irregular, more or less vein-limited, reaching to 10 mm in diameter. The spots were initially uniformly brown to reddish brown, turning pale brown with a purplish margin and showing grayish patches on the lesion due to heavy fructification. The causative agent of the leaf spot disease was identified as Cercospora malayensis. The pathogenicity test was conducted with similar results, which fulfilled Koch's postulates. This is the first report of C. malayensis infection of kenaf in Korea.

• 한국작물학회지
• /
• 제25권1호
• /
• pp.47-53
• /
• 1980

대두 갈문병에 대한 저항성 인자원을 개발하기 위하여 수집재래종대두의 저항성을 검정하고 낙엽률과 수량구성형질간의 관계를 구명한 결과를 다음과 같이 요약하였다. 1. 본시험에 공시한 수집재래종대두 1428계통의 약60% 이상이 심한 황변현상과 조기낙엽에 이르는 가장 높은 리병성 반응(리병지수 5)을 보였으며 약 9%인 136계통은 병반은 형성하나 병반 주위조직의 황변현상이 나타나지 않았으며 이들의 대부분은 녹색종피 계통이었다. 2. 대두 갈문병의 접종시기는 제2～3 복엽기가 효과적이었으며 신엽보다는 성엽에서 병의 진전속도가 빨 간다. 3. 대두 갈문병의 접종 4주 후에 조사한 초생단업의 낙엽률은 비접종구에 비해 약 82% 증가하였으며 황변현상이 나타나지 않는 연색종피 계통과 황변환상을 나타내는 품종간에 차이가 없는 것으로 보아 이들 연색종피 계통을 저항성으로 간징하기는 어려웠다. 4. 대두의 조기낙엽은 초장과 분지수에는 영향이 없었으나 절수, 협수 및 백립중에는 유의성 있는 부의 상관을 보임으로서 수량감소의 중요한 요인이 될것으로 보였다.

• Mycobiology
• /
• 제44권3호
• /
• pp.187-190
• /
• 2016

In July 2015, diseased leaves of black chokeberry (Aronia melanocarpa) were observed in Danyang and Gochang, Korea. The symptoms appeared as circular or irregular brown leaf spots, from which Alternaria tenuissima was isolated. The isolates were cultured on potato dextrose agar, and their morphological characteristics were observed under a light microscope. The colonies were whitish to ash colored. The pathogenicity test on healthy black chokeberry leaves produced circular brown spots, in line with the original symptoms. Molecular analyses of the ITS, GPD, RPB2, and TEF genes were conducted to confirm the identity of the pathogen. The phylogeny of the multi-gene sequences indicated that the causal agent was A. tenuissima. This study is the first report of A. tenuissima leaf spot on black chokeberry (A. melanocarpa).

• The Plant Pathology Journal
• /
• 제16권6호
• /
• pp.328-330
• /
• 2000

A terget leaf spot of red and white clovers was observed during 1998-2000 growing seasons in several fields of Chungnam and Chungbuk provinces in Korea. Lesions were circular to oval in outline, brown to dark brown, ranging from a pinpoint to 3-4 mm in diameter, often concentrically zonate and presenting a target effect. A fungus associated with the disease was identified as Stemphylium sarciniforme based on the morphological characteristics of the conidiophores and conidia. The fungus was pathogenic on red and white clovers in the inoculation test. This is the first record of a terget leaf spot of red and white clovers in Korea.

• 한국균학회지
• /
• 제51권1호
• /
• pp.63-68
• /
• 2023

From June to August 2021, we surveyed diseases affecting beet (Beta vulgaris subsp. vulgaris) plants in Cheolwon, Hoengseong, and Pyeongchang regions in Gangwon Province, Korea. We observed severe leaf spot symptoms, such as brown to dark circular or irregular spots on the leaves, in plants. Disease incidence in the plant leaves in the fields investigated at the three locations ranged from 1 to 80%. Five single-spore isolates of Phoma sp. were obtained from the diseased leaves and identified as Neocamarosporium betae based on their cultural, morphological, and molecular characteristics. Three isolates of N. betae were subsequently tested to confirm their pathogenicity in beet plants via artificial inoculation. The tested isolates caused leaf spot symptoms in the inoculated plants, similar to those observed in the plants in the investigated fields. Therefore, our findings revealed N. betae as the pathogen causing beet leaf spot in Korea.

• 한국식물병리학회지
• /
• 제14권5호
• /
• pp.397-401
• /
• 1998

Asexual spores of Mycosphaerella nawae were profusely produced on PDA after a prolonged incubation at $25^{\circ}C$ for 90 days. When persimmon trees were artificially inoculated by the conidial suspension, typical symptoms of circular leaf spot of persimmon appeared on the leaves two month later. The imperfect stag of the fungus was identified as Ramularia sp. based on following morphological characteristics examined under a light microscope and a scanning electron microscope. Conidia were mostly ellipsoid, but occasionally cylindrical, elongated oval, taro, peanut or gourd shapes and measured as 12.2~32.6$\times$6.1~10.2 ${\mu}{\textrm}{m}$. erect, hyaline, colorless-light brown. Conidia were formed solitarily or in chains on a medium and infected leaves. Conidiophore was erect, hyaline, colorless-light brown. and the size was 20.4~102.0$\times$3.1~10.2 ${\mu}{\textrm}{m}$, respectively. In this paper, we firstly demonstratrated that asexual spores of M. nawae induced persimmon circular leaf spot in nature as well as sexual spores of the fungus. Therefore, it is hypothesized that the imperfect stage of the fungus plays an important role in nature for epidemics as secondary inoculum.