• Research in Plant Disease
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• v.22 no.2
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• pp.116-121
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• 2016

In 2015, stem blight of Rubus crataegifolius was observed in Pohang, Korea. The symptoms began as dark red spots in the stem, which led to stem blight, then leaf blight, and eventually resulted in death. A fungal isolate was obtained from a symptomatic stem and incubated on a potato dextrose agar plate. The isolated fungus produced white, cloudy mycelia turned black in 3 days. Based on the morphological characteristics, the causal fungus was assumed to be Botryosphaeria sp. A pathogenicity test was conducted according to Koch's postulates. To identify the causal agent, the combined sequence of the internal transcribed spacer, ${\beta}$-tubulin, and translation elongation factor $1{\alpha}$ genes were used for phylogenetic analysis. Approximately 1,200 bp of the combined sequence clearly suggested that the isolated pathogen was Botryosphaeria parva. This is the first report on stem blight in R. crataegifolius caused by B. parva in Korea.

• Mycobiology
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• v.42 no.3
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• pp.269-273
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• 2014

During 2010 and 2012 grape harvest seasons in Gyeonggi-do, Korea, a white stain symptom was observed on the harvested grape fruits in 'Campbell-Early' and 'Kyoho' varieties. In samples collected from the infected vine, two different strains of pathogenic fungi have been found and identified as Acremonium acutatum and Trichothecium roseum based on fungal morphology and nucleotide sequence of internal transcribed spacer (ITS) and supported by the phylogenetic analysis of the rDNA-ITS region. The DNA homologies of the isolated strains were 99.8% and 99.6% identical with T. roseum (IFB-22133) and A. acutatum (CBS682.71), respectively. In the pathogenicity test, the spores of A. acutatum and T. roseum sprayed on the grapes caused white stain symptoms on the fruits in two weeks after the artificial inoculation, which is similar to observations in the field. To our knowledge, this is the first report of white stain symptoms caused by A. acutatum and T. roseum on the grapes in Korea.

• Mycobiology
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• v.45 no.2
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• pp.114-118
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• 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.

• Mycobiology
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• v.42 no.2
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• pp.203-205
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• 2014

In 2010, symptoms of leaf and stem rot were observed on potted plants (Peperomia quadrangularis) in a greenhouse in Yongin, Korea. The causative pathogen was identified as Myrothecium roridum based on morphological data, internal transcribed spacer sequence analysis, and pathogenicity test. To our knowledge, this is the first report of M. roridum causing leaf and stem rot disease on P. quadrangularis in Korea and elsewhere worldwide.

• Mycobiology
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• v.44 no.3
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• pp.187-190
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• 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 Korean Journal of Mycology
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• v.45 no.4
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• pp.381-385
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• 2017

Sclerotinia rot was observed on Ixeridium dentatum cultivated as a succeeding crop in a garlic field in Seosan-si, Korea during the growing season in 2016 and 2017. Symptoms progressed from the initial irregular, water-soaked spots on main stems to wilting and eventually to plant death. White, cottony mycelia and black, irregular sclerotia formed on the basal stem and on soil surfaces. The optimal temperature of hyphal growth and sclerotia germination were $20^{\circ}C$ and $25^{\circ}C$, respectively. Sequence analysis of the internal transcribed spacer (ITS) regions revealed that the three strains isolated from Ixeridium dentatum are grouped with Sclerotinia sclerotiorum. Three strains were identified as Sclerotinia sclerotiorum based on morphological features, ITS sequence, and pathogenicity test. To the best of our knowledge, this work is the first report of Sclerotinia sclerotiorum causing sclerotinia rot on Ixeridium dentatum in Korea.

• The Plant Pathology Journal
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• v.36 no.4
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• pp.378-383
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• 2020

The objective of this research was introduction of chit42 to tuber mustard plants through Agrobacteriummediated transformation against white mold caused by Sclerotinia sclerotiorum. The binary plasmid pGisPEC1 was used in this study. Polymerase chain reaction analysis detected the transgene in 27 transformants with a transformation efficiency of 6.9%. Southern blot test was used to assess the copy number of transgene in tuber mustard plants. One, two, two, and two chit42-related bands were observed in the transformed lines TMB4, TMB7, TMB12, and TMB18, respectively. Enzymatic tests showed a significant increase in the activity of endochitinase in protein isolated from leaf tissues of chit42 transgenic 75-day tuber mustard lines. The pathogenicity of three pathogen isolates was tested on the leaves of transformed plans. The results of current study showed that expression of the gene chit42 in tuber mustard plants markedly reduced infection radius on the leaves 7 days after inoculation with the fungus.

• The Plant Pathology Journal
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• v.19 no.5
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• pp.227-230
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• 2003

Ripe rot was commonly found in overripe kiwifruits (Actinidia deliciosa) during a disease survey conducted in Jeju and Jeonnam provinces in Korea in 1999. While the disease did not manifest any clear external symptoms on kiwifruits, it caused portion of the fruit surface to collapse. Watersoaked flesh tissue could be seen on the sunken part when the skin of the collapsed portion was peeled off. The milky internal symptom with dark green margin developed concentrically as the fruit ripened. A species of Botryosphaeria was consistently isolated from lesions showing typical symptoms of ripe rot on kiwifruit, and its pathogenicity was confirmed by artificial inoculation test on healthy kiwifruits. The fungus was also pathogenic to apple and pear. The mycological characteristics of the fungus were consistent with those of Botryosphaeria dothidea. This is the first report on the detailed mycological characteristics of the causal organism of post-harvest ripe rot of kiwifruit in Korea.

• The Plant Pathology Journal
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• v.19 no.4
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• pp.195-199
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• 2003

Pink root of onion occurred in the fields of the Onion Experimental Station and in the main onion cultivation area in Korea in 1998 and 1999, respectively. The casual fungus of pink root was isolated only from apricot agar. Formation of pycnidia and pycnidiospores of the fungus was highest in alternating cycles of 12 hours near ultraviolet light and 12 hours in dark condition. Its morphological characteristics and pigment formation on water agar were identical with that of Pyrenochaeta terrestris. The optimum temperature for the growth of the fungus and disease development was $25-28^{\circ}C$. When onion seeds were inoculated with the spore suspension, incubated in test-tube and sown in potted soil, disease symptoms developed in onion roots 7 and 30 days after inoculation.

• Mycobiology
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• v.47 no.4
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• pp.408-414
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• 2019

Crinum asiaticum and Hymenocallis littoralis, commonly known as spider lilies are bulbous perennial and herbaceous plants that widely planted in Malaysia as ornamental. During 2015-2016, symptom of leaf blight was noticed on the hosts from several locations in Penang. The symptom appeared as irregular brown to reddish lesions surrounded by yellow halos. As the disease progressed, the infected leaves became blighted, dried, and fell off with the presence of black microsclerotia and pycnidia on the lesions parts. The present study was conducted to investigate the causal pathogen of leaf blight on C. asiaticum and H. littoralis. Based on morphological characteristics and DNA sequences of internal transcribed spacer (ITS) region and translation elongation factor 1-alpha (TEF1-α) gene, the causal pathogen was identified as Macrophomina phaseolina. Phylogenetic analysis of combined dataset of ITS and TEF1-α grouped the isolates studied with other isolates of M. phaseolina from GenBank. The grouping of the isolates was supported by 96% bootstrap value. Pathogenicity test proved the role of the fungus in causing leaf blight on both hosts.