• The Korean Journal of Mycology
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• v.29 no.2
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• pp.127-130
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• 2001

A Pythium species was isolated from roots of Codonopsis pilosula showing wilt symptoms in a field at Yonchon, Kyonggido of Korea from late June to early August in 2000. The Pythium species was identified as Pythium myriotylum Drechsler based on various mycological characteristics. The isolate was strongly pathogenic when inoculated to root of C. pilosula plants in pot. The inoculated plants showed typical symptoms of root rot, resulting in reduced growth of root and consequently wilting of above ground part of plants. Pythium root rot of C. pilosula caused by P. myriotylum has not been reported previously in Korea.

• The Plant Pathology Journal
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• v.17 no.2
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• pp.101-105
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• 2001

A disease survey on the carnation (Dianthus caryophyllus L.) wilt was conducted during the high temperature period (June through August) and the low temperature period (February through May) in 58 greenhouses of its major cultivation areas, including Pusan, Kimhae, and Changwon in Korea from 1998 to 1999. The disease incidence was averaged 5.4% and 11.9% in the low and high temperature periods, respectively. Severe damage was found in summer with high incidences of around 50% in some greenhouses. Close examination of the symptoms and isolation of the causal agent revealed that there was a new disease different from Fusarium wilt caused by Fusarium oxysporum f. sp. dianthi, which was determined as the stub dieback caused by F. was cetermined as the stub dieback caused by F. graminearum (teleomorph : Gibberella zeae). The stub dieback symptoms involved brown rot of stem that started usually from the portion of cutting without discoloration of inner vascular tissues. Seven out of 38 isolates from the wilted plants were identified as F. graminearum, while the others as F. oxysporum f. sp. dianthi. Mycological characteristics of the stub dieback pathogen including colony color, absence of microconidia, and the shape of macroconidia, were consistent with F. graminearum previously described. This is the first report of the carnation stub dieback in Korea.

• The Plant Pathology Journal
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• v.17 no.2
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• pp.110-113
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• 2001

Post-harvest diseases of kiwifruit caused severe damages on the fruits during storage, transportation, marketing and consumption. Phomopsis sp. was reported to be one of the major causal organisms of post-harvest fruit rots of kiwifruit. Symptoms of stem-end rot caused by Phomopsis sp. appeared at the stem-end area of the fruit as it ripened. The brown pubescent skin at the area became soft and lighter in color than the adjacent firm healthy tissues. A watery exudate and white mycelial mats were frequently visible at the stem-end area forming a water-drop stain down the sides on the dry brown healthy skin. When the skin was peeled back, the affected flesh tissue was usually watersoaked, disorganized, soft and lighter green than the healthy tissue. Phomopsis sp. was consistently isolated from the diseased fruits, and its pathogenicity was confirmed by an artificial inoculation test on healthy fruit of kiwifruits. The mycological characteristics of the telemorph state of the fungus produced on potato-dextrose agar were in accordance with those of Diaporthe actinidiae. This is the first report on the occurrence of a telemorph state of D. actinidiae as the causal organism of stem-end rot of kiwifruit in Korea.

• Journal of Ginseng Research
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• v.32 no.1
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• pp.26-32
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• 2008

A total of 29 Botrytis were isolated from ginseng gray mold at 8 locations in Korea from June to July, 2004 and 2005. The causative agent of them was identified as Botrytis cinerea based on morphological characteristics of conidia and RPB2 gene sequence analysis. In inoculation experiments with sclerotia, one isolate was pathogenic to ginseng plant whereas two isolates were non-pathogenic. Scanning electron microscopy revealed that the sclerotia of pathogenic isolate has rough surface and that of non-pathogenic isolate very smooth surface. Optimum temperature and culture conditions for sclerotia production were $5{\sim}20^{\circ}C$ and darkness, respectively. The number of sclerotia was increased tenfold on media added with 0.5% old stem fragment of ginseng.

• The Korean Journal of Mycology
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• v.33 no.2
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• pp.98-102
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• 2005

In 2003 to 2005, the root rot of Japanese angelica (Aralia elata) was surveyed in nursery beds of Korea, where incidence of the disease often reached up to 100%. Three isolates were obtained from the infected roots, and identified as Phytophthora cactorum on the basis of cultural, morphological characteristics and molecular analysis. The isolates were characterized by having markedly papillate and broadly ovoid deciduous sporangia. The optimum temperature for mycelium growth was at $25^{\circ}C$ on V8 juice agar. Pathogenicity of the isolates was confirmed by soil mixture inoculation. Approximately 900 bp of ITS rDNA was amplified from all 3 isolates and band pattern of restriction fragments observed by Alu I, Msp I, and Taq I digestion also supported the result of the morphological identification when compared with PhytID database.

• Korean Journal Plant Pathology
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• v.14 no.2
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• pp.109-114
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• 1998

To investigate Phomopsis species causing fruit decays of Japanese apricot, apple and kiwifruit, we collected diseased fruits from the fruit markets in 1995 and 1996 respectively. Phomopsis mali Roberts was identified based on cultural characteristics, morphological aspects and pathogenicity. There were no remarkable differences with respect to $\alpha$ and $\beta$ conidia, growth rates and colony characters among the isolates from Japanese apricot, apple and kiwifruit. The pathogens grew more than 70 mm on potato dextrose agar in 5 days at $25^{\circ}C$. The agar was slightly discolored by the production of a reddish purple pigment under the light at $25^{\circ}C$ and 3$0^{\circ}C$ respectively. Only $\alpha$ spores of the different isolates of P. mali were formed at 15$^{\circ}C$ and $\beta$ spores were mainly produced at 3$0^{\circ}C$, but and $\alpha$ and $\beta$ spores were produced in approximately equal numbers at 2$0^{\circ}C$ and $25^{\circ}C$. Pycnidia were a few under the dark condition but were abundant at wide range of 15~3$0^{\circ}C$ under near ultra violet illumination. Conidia were two types : $\alpha$ spores were unicellar, fusoid, hyaline and biguttulate, whereas $\beta$ sores were unicellar, acicular to filiform, straight or hooked and hyaline. An ascigerous stage was not formed in cultures or in nature. Isolates of Phomopsis mali from japanese apricot, apple and kiwifruit could infect fruits of apple, pear, apricot, Japanese apricot and kiwifruit. There were some differences in pathogenicity depending on stocks of fruit crops tested.

• The Plant Pathology Journal
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• v.22 no.3
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• pp.215-221
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• 2006

Gibberella zeae (anamorph: Fusarium graminearum) is an important pathogen of cereal crops. This fungus produces a broad range of secondary metabolites, including polyketides such as aurofusarin (a red pigment) and zearalenone (an estrogenic mycotoxin), which are important mycological characteristics of this species. A screen of G. zeae insertional mutants, generated using a restriction enzyme-mediated integration (REMI) procedure, led to the isolation of a mutant (Z43R606) that produced neither aurofusarin nor zearalenone yet showed normal female fertility and virulence on host plants. Outcrossing analysis confirmed that both the albino and zearalenone-deficient mutations are linked to the insertional vector in Z43R606. Molecular characterization of Z43R606 revealed a deletion of at least 220 kb of the genome at the vector insertion site, including the gene clusters required for the biosynthesis of aurofusarin and zearalenone, respectively. A re-creation of the insertional event of Z43R606 in the wild-type strain demonstrated that the 220-kb deletion is responsible for the phenotypic changes in Z43R606 and that a large region of genomic DNA can be efficiently deleted in G. zeae by double homologous recombination. The results showed that 52 putative genes located in the deleted genomic region are not essential for phenotypes other than the production of both aurofusarin and zearalenone. This is the first report of the molecular characterization of a large genomic deletion in G. zeae mediated by the REMI procedure.

• Research in Plant Disease
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• v.18 no.4
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• pp.396-398
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• 2012

Pink mold rot of tomato occurred very severly on tomato farm in Paju, Gyounggi Province, Korea, in July 2005. The infected fruits were dropped and abandoned and the symptoms were similar to calcium deficient tomatoes. But symptom was a slight water-soaked area on or near the blossom end of the fruit and firm greyish-brown lesions were most found at the blossom-end of affected fruits. lesions caused by the pink mold fungus possess a water soaked margin and rise to characteristic orange-pink spores. Also when the diseased tomato was cut, the inside of tomatoes showed completely rotted with pink mold. The causal fungus was identified as Trichothecium roseum based on mycological characteristics. This is the first report of T. roseum infecting greenhouse tomatoes in Korea.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.131.2-132
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• 2003

White rot on garlic caused by Sclerotium cepivorum firstly occurred at Goheoung, Jeonnam in 1998. Thereafter, the disease rapidly spread throughout the country except Gangwon and became a major limiting factor for the cultivation of various Allium species such as garlic, onion, and welsh onion. The disease that has not been reported on a wild garlic(Allium monanthum) previously occurred severely at Seosan, Choongnam in 2003. Among cultivation areas in the region, 10.7％ were infected by the disease and the ratio of diseased plant reached up to 55.0％ in some heavily infected fields. Two species of Sclerotium were consistently isolated from infected samples and identified as S. cepivorum or another Sclerotium sp. Averaged size of sclerotium of the former was 455.0x562.2 urn, while the later was 374.4${\times}$347.2$\mu\textrm{m}$. Patogenicity to Allium species and mycological characteristics such as sclerotium size, growth temperature, and microconidia of the fungi were similar to those reported on other Allium species previously. Consequently, the wild garlic is a newly reported host of the two pathogenic fungi in Korea.

• Research in Plant Disease
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• v.9 no.3
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• pp.149-152
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• 2003

Black leaf spot disease occurred on Dendrobium phalaenopsis grown in farmer's fields located in Bonggangmyon, Gwangyang-eup, Jeonnam, Korea. Black small spots occurred on leaves at initial stage of infection and the infected leaves turned yellow from the tip. The yellow leaves were falled, resulting in stem blighting or eventual death of the entire plant. White mycelial colony of the causal fungus grown on potato dextrose agarturned dark violet later and optimum temperature for the mycelial growth was $25^{\circ}C$. The causal fungus isolated from the black leaf spot on D. phalaenopsis was identified as Fusarium moniliforme based on the mycological characteristics and pathogenicity. The fungus also caused same symptoms on leaves of Phalaenopsis sp. and Cymbidium sp. as well sa D. phalaenopsis by wound inoculation. This is the first report on black leaf spot of D. phalaenopsis caused by F.moniliforme in Korea.