• 식물병연구
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• 제24권2호
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• pp.138-144
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• 2018

In December 2016, stem rot symptoms were observed on Persian buttercup (Ranunculus asiaticus) plants in Chilgok, Gyeongbuk, Korea. In the early stage of the disease, several black spots appeared on the stem of infected plants. As the disease progressed, the infected stem cleaved and wilted. The causal agent was isolated from a lesion and incubated on Reasoner's 2A (R2A) agar at $25^{\circ}C$. Total genomic DNA was extracted for phylogenetic analysis. Based on the 16S rRNA gene analysis, the isolated strain was found to belong to the genus Pseudomonas. To identify the isolated bacterial strain at the species level, the nucleotide sequences of the gyrase B (gyrB) and RNA polymerase D (rpoD) genes were obtained and compared with the sequences in the GenBank database. As the result, the causal agent of the stem rot disease was identified as Pseudomonas marginalis. To determine the pathogenicity of the isolated bacterial strain, it was inoculated into the stem of healthy R. asiaticus plant, the inoculated plant showed a lesion with the same characteristics as the naturally infected plant. Based on these results, this is the first report of bacterial stem rot on R. asiaticus caused by P. marginalis in Korea.

• 한국식물병리학회지
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• 제14권6호
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• pp.741-743
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• 1998

A bacterial disease of pepper (Capsicum annuum L.) that rooted the stem nodes to black was found in pepper plants which cultivated in plastic house at Chungdo, Kyungpook, Korea in March, 1998. Bacterial isolates derived from the diseased peppers were pathogenic to potato, eggplant and Chinese cabbage but, was not pathogenic to chrysanthemum by artificial inoculation. On the basis of bacteriological characteristics and pathogenicity test on host plants, the causal organism of the node soft rot of pepper is identified as Erwinia carotovora subsp. carotovora and the name of disease is proposed as bacterial node soft rot of pepper.

• 한국작물학회지
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• 제4권1호
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• pp.103-108
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• 1968

담배 각종병해저항성 품종육성의 기초자료를 얻기 위하여 우리나라 재래종에 대한 몇가지 병해에 대한 저항성검정을 하였다. (1) 역병에는 우방초, 오심엽초만이 중정도의 저항성이 있으며 수안초, 우설초, 광초 등이 그 다음이고 그 외품종은 모두 나병성이였다. DB 101, $H_2$, BY 4 등은 재래종보다 저항성이였다. (2) 흑근병에는 목기초, 우방초, 오심엽초가 중정도의 저항성이며 우설초, 수안초, 회초가 다음이며 향초는 BY 4만은 못하나 재래종중에서 가장 나병율이 높았다. (3) 야화병에는 대부분 나병율이 높은 편이나 흑초, 회초, 우방초가 약간 저항성이 인정되고 그 외품종은 거의 나병성이다. (4) 적성병에는 오심엽초가 고도의 저항을 엿보이며 우방초, 향초, 목기초 등이 중정도이고 광초, 우설초는 나병성이였다. 대조품종인 BY4나 Beinhart 1,000-1보다는 모두 나병율이 낮았다. (5) CMV-Y에 대하여서는 향초가 고도의 저항성이 인정되고 회초, 가자초가 저도이기는 하나 저항성이 있는 듯하다. (6) Blue mold병에 대에 하여는 공시품종 모두가 고도의 나병성임으로 이에 대한 저항성품종의 발굴이 절실히 요망된다.

• International Journal of Industrial Entomology and Biomaterials
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• 제16권2호
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• pp.49-56
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• 2008

A preliminary survey on the incidence and intensity of root disease complex (association of Meloidogyne incognita and root rot pathogens) was carried out in the sericultural areas of Karnataka. A total of 280 mulberry gardens were surveyed in 14 districts of Karnataka belonging to different types of soil (red sandy, red loamy and black cotton), farming systems (irrigated and rainfed), varieties (V-1, K-2, Local and S-13) and age of the plants (0-5, 5-10 and 10-15 years). It was observed that the association of M. incognita with Botryodiplodia theobromae and Fusarium solani causes the root disease complex in mulberry. Of the 280 gardens visited, 94 were infested with the disease complex and incidence was recorded as 33.6%. The higher intensity of root disease complex was observed when the root system had more than 100 galls/plant with infection of mixed population of B. theobromae and F. solani in sandy soil under irrigated farming. The 5-10 years old mulberry plantation with V-I variety was found to be most susceptible to root disease complex. Districts like Mysore, Kolar, Mandya, Tumkur, Chitradurga and Bangalore were observed as sensitive areas. Further, the wounds caused by M. incognita in mulberry roots favour the easy entry of root rot pathogens, which increased the severity of the disease very fast.

• The Plant Pathology Journal
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• 제39권3호
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• pp.275-289
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• 2023

Fungal isolates from infected Chinese quince trees were found to cause black rot in Yeongcheon, Gyeongsangbuk Province, Korea. The quince leaves withered and turned reddish-brown and fruits underwent black mummification. To elucidate the cause of these symptoms, the pathogen was isolated from infected leaf and fruit tissues on potato dextrose agar and Levan media. Several fungal colonies forming a fluffy white or dark gray mycelium and two types of fungi forming an aerial white mycelium, growing widely at the edges, were isolated. Microscopic observations, investigation of fungal growth characteristics on various media, and molecular identification using an internal transcribed spacer, β-tubulin, and translation elongation factor 1-α genes were performed. The fungal pathogens were identified as Diplodia parva and Diplodia crataegicola. Pathogenicity tests revealed that the pathogen-inoculated fruits exhibited a layered pattern, turning brown rotting; leaves showed circular brown necrotic lesions. The developed symptoms were similar to those observed in the field. Fungal pathogens were reisolated to fulfill Koch's postulates. Apples were inoculated with fungal pathogens to investigate the host range. Strong pathogenicity was evident in the fruits, with browning and rotting symptoms 3 days after inoculation. To determine pathogen control, a fungicidal sensitivity test was conducted using four registered fungicides. Thiophanate-methyl, propineb, and tebuconazole inhibited the mycelial growth of pathogens. To the best of our knowledge, this is the first report on the isolation and identification of the fungal pathogens D. parva and D. crataegicola from infected fruits and leaves of Chinese quince, causing black rot disease in Korea.

• 식물병연구
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• 제12권2호
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• pp.134-138
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• 2006

2003년부터 2004년 평창 지역의 브로콜리 포장에서 새로운 병해가 발견되었다. 유묘 감염이 되었을 때 떡잎의 주위로부터 검게 변색되기 시작하여 결국 떡잎이 떨어지고 유묘는 죽었다. 성체에서는 잎 가장자리로부터 엽맥을 타고 진전되어 V 자 또는 U 자형의 노란색 병반을 형성하였다. YDC 배지에서 병원세균을 순수 분리하였을 때 Xanthomonas 속 세균의 전형적인 특정인 노란색 색소를 띤 세균이 형성되었다. 분리된 세균을 $10^8 cfu/ml$로 현탁 한후 3 주 동안 자란 브로콜리, 양배추, 배추, 케일, 무에 가위 접종하여 병원성을 확인하였다. 지방산 조성 및 함량, 다양한 탄소원 이용정도 및 16S rDNA 염기서열를 이용하여 분리세균 SL4797 과 SL4800 을 대조균주 X. campestris pv. campestris NCPPB528 과 비교하였을 때 매우 유사하였다. 이 논문은 국내에서 브로콜리의 검은썩음병 최초 보고이다.

• The Plant Pathology Journal
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• 제19권2호
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• pp.79-84
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• 2003

Sclerotinia rot occurred severely on some vegetable crops grown in Namyangju, Yangpyung, and Yangiu areas in Korea in 2001-2002. The crops infected with Scterotinia sp. were Adenophora remotiflora, Armoracia lapathfolia, Angelica acutiloba, Angelica archangelica, Anthriscus sylvestris, Aster tataricus, Beta vulgaris var. cicla, Brassica campestris var. marinosa, Brassica juncea var. laciniata, Chicholium intybus, Lactuca indica var. dracoglossa, Lactuca sativa var. oak-leaf, Petroselinum crispum, and Phyteuma japonicum. The fungus associated with the disease was identified as Sclerotinia sclerotiorum, based on the morphological characteristics of the pathogen. The symptoms were water-soaked spots that enlarged later and became a watery soft rot. Infected parts became yellow and then turned brown, followed by death of the whole plant. White mycelia developed on the upper petioles and leaves and on the soil where these plant parts lay. Then black sclerotia in variable size and shape formed from the mycelial mass. Pathogenicity of the fungus was proven by artificially inoculating each crop. This is the first report of Sclerotinia rot on the listed vegetable crops in Korea.

• The Plant Pathology Journal
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• 제22권4호
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• pp.375-380
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• 2006

In the survey from 1992 to 2000, twenty-eight parasitic diseases were observed in major apple producing areas in Korea. The predominant apple diseases were white rot(Botryosphaeria dothidea), Marssonina blotch(Marssonina mali), Valsa canker(Valsa ceratosperma), Alternaria leaf spot(Alternaria mali), and bitter rot(Collectotrichum gloeosporioides and C. acutatum). Apple scab that reappeared in 1990 after disappearance for 15 years was disappeared again since 1997. A viroid disease(caused by apple scar skin viroid) was newly found in this survey. The five diseases, fire blight(Erwinia amylovora), black rot(Botryosphaeria obtusa), scab(Cladosporium carpophilum), Monochaetia twig blight(Monochaetia sp.), and brown leaf spot(Hendersonia mali), which had once described in 1928 but no further reports on their occurrence, were not found in this survey. However, blossom blight(Monilinia mali), brown rot(Monilinia fructigena), and pink rot(Trichothecium roseum), which did not occur on apple after mid 1970s, were found in this survey.

• Mycobiology
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• 제28권4호
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• pp.177-179
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• 2000

A soft rot of fruits caused by Rhizopus nigricans occurred on peach (Prunus persica var. vulgaris) in The Chinju City Agricultural Products Wholesale Marke during in summer season of 2000. The disease infection usually started from wounding after harvest fruits, and then moved to outside. At first, the lesions started with water soaked and rapidly softened and diseased area gradually expanded. In severely infected film house, the rate of infected fruits reached 65.2%. Numerous sporangiospores were produced on the diseased fruits. Most of the sporangiospores were appeared to be readily dispersed in the air. The mycelia grew surface of fruits and produced stolons. Colonies on potato dextrose agar at $25{\sim}30^{\circ}C$ white cottony at first becoming heavily speckled by the presence of sporangia and the browinish black at maturity, spreading rapidly by means of stolons fired at various points to the substrate by rhizoids. Sporangia were $85.3{\sim}243.5{\times}53.4{\sim}219.2\;{\mu}m$ in size and were globose or sub-globose with. somewhat flattened base. The color of sporangia was white at first and then turned black with many spores, and never over-hanging. Sporangiophores were $8.9{\sim}36.6\;{\mu}m$ in width, smooth-walled, non-septate, light brown, simple, long, arising in groups of $3{\sim}5$ from stolons opposite rhizoids. Sporangiospores was $9.7{\sim}24.8{\times}5.9{\sim}15.8\;{\mu}m$, irregular, round, oval, elongate, angular, and browinish-black streaked. Columella was $70.2{\times}149.7{\mu}m$. brownish gray, and umberella-shaped when dehisced. The causal organism was identified as. Rhizopus nigricans Lind on the basis of the morphiogical characteristics of the fungus. Rhizopus soft rot on peach (Prunus persica) caused by the fungi has not been reported in Korea. This is the first report of rhizopus soft rot on peach caused by Rhizopus nigricans in Korea.

• The Plant Pathology Journal
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• 제30권3호
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• pp.323-329
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• 2014

Two cultivars Buram-3-ho (susceptible) and CR-Hagwang (moderate resistant) of kimchi cabbage seedlings showed differential defense responses to anthracnose (Colletotrichum higginsianum), black spot (Alternaria brassicicola) and black rot (Xanthomonas campestris pv. campestris, Xcc) diseases in our previous study. Defense-related hormones salicylic acid (SA), jasmonic acid (JA) and ethylene led to different transcriptional regulation of pathogenesis-related (PR) gene expression in both cultivars. In this study, exogenous application of SA suppressed basal defenses to C. higginsianum in the 1st leaves of the susceptible cultivar and cultivar resistance of the 2nd leaves of the resistant cultivar. SA also enhanced susceptibility of the susceptible cultivar to A. brassicicola. By contrast, SA elevated disease resistance to Xcc in the resistant cultivar, but not in the susceptible cultivar. Methyl jasmonate (MJ) treatment did not affect the disease resistance to C. higginsianum and Xcc in either cultivar, but it compromised the disease resistance to A. brassicicola in the resistant cultivar. Treatment with 1-aminocyclopropane-1-carboxylic acid (ACC) ethylene precursor did not change resistance of the either cultivar to C. higginsianum and Xcc. Effect of ACC pretreatment on the resistance to A. brassicicola was not distinguished between susceptible and resistant cultivars, because cultivar resistance of the resistant cultivar was lost by prolonged moist dark conditions. Taken together, exogenously applied SA, JA and ethylene altered defense signaling crosstalk to three diseases of anthracnose, black spot and black rot in a cultivar-dependent manner.