• The Korean Journal of Mycology
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• v.35 no.1
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• pp.28-32
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• 2007

Fruiting bodies of Inonotus obliquus were collected from the trunk of Betula ermani at 1,100 m of Mt. Odae. Diameter range of the trees at breast height (DBH) was $10{\sim}50$ cm and size range of the sclerotia was $8{\times}5{\sim}20{\times}16cm$. Relationships between the examined strains and Inonotus obliquus strain registered in National Center for Biotechnology Information (NCBI) were very near. And all of 10 strains except strains registered in NCBI showed high homologous characteristics by neighbour joining analysis of ITS sequence. Mycelial growth showed a big difference among strains. Mycelial growth of KFRI 744 was fastest and KFRI 739 was slowest. Difference of mycelial growth between KFRI 735 and 738 was slight, but the difference of mycelial growth between KFRI 744 and 739 was almost twice. Also weight reduction rate among strains showed some difference. KFRI 744 was highest and KFRI 741 was lowest. Vegetative incompatibilities were observed in all mycelial pairings except for KFRI 740-741 and KFRI 742-743 combinations.

• Research in Plant Disease
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• v.19 no.1
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• pp.12-20
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• 2013

To isolate antagonistic bacteria against sclerotinia rot of lettuce, caused by Sclerotinia sclerotiorum, soil samples were collected from the diseased greenhouse field in Namyangju city, Gyeong-gi province from 2007 to 2008. A total of 196 bacterial isolates were isolated using serial dilution method. In dual culture assay in vitro, 26 isolates showed more than 80% of inhibition rates of mycelial growth of S. sclerotiorum. Based on 16S rDNA sequence analysis, the 26 isolates were identified as Bacillus megaterium, B. cereus, B. subtilis, Arthrobacter nicotianae, A. ramosus, Pseudomonas filiscindens, Stenotrophomonas maltophilia, Brevibacterium frigoritolerans and Sphingobacterium faecium. The 26 isolates inhibited the mycelial growth of S. sclerotiorum up to 80% and the sclerotial germination 0-100%. In the greenhouse pot test of ten isolates conducted in summer, 2 isolates B. megaterium (DK6) and B. cereus (C210) showed control efficacy on sclerotia viability of S. sclerotiorum, 20% and 35%, respectively. In the greenhouse pot test in winter, the disease incidence of the control group was 80%, whereas those of 9 isolates among 26 were approximately 20%. From the result, the 9 isolates are expected as potentially antagonistic bacteria for biological control of sclerotinia rot of lettuce caused by S. sclerotiorum.

• Research in Plant Disease
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• v.23 no.1
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• pp.56-59
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• 2017

During growing season of 2011 to 2013, Sclerotinia rot symptoms consistently have been observed on basil in Yesan-gun, Chungcheongnam-do in Korea. The typical symptom formed initially brownish spot on leaf and stem, and then advancing margins, wilting the whole plant and blighting, eventually died. On the surface of diseased lesions was observed cottony, white, dense mat of mycelial growth, and sclerotia ($30-100{\mu}m$ diameter) formed on stem and leaf. Morphological and cultural characteristic on potato dextrose agar, color of colony was white and colorless chocolate, sclerotium of irregular shape of the oval was black and $5-50{\mu}m$ diameter in size. In pathogenicity test, necrosis and wilt of the inoculated stem were observed in all plants and the pathogen was reisolated from stems. On the basis of mycological characteristics, pathogenicity, and internal transcribed spacer rDNA sequence analysis, this fungus was identified as Sclerotinia sclerotiorum. This is the first report of Sclerotinia rot on basil caused by S. sclerotiorum in Korea.

• Korean Journal Plant Pathology
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• v.13 no.4
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• pp.200-204
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• 1997

The effect of water potential ($\psi_W$) and temperature on mycelial growth and sclerotial production of Sclerotium cepivorum was determined in potato dextrose agar(PDA) and potato dextrose broth (PDB) adjusted to different $\psi_W$ with NaCI, KCI, sucrose or polyethylene glycol (PEG) at 15, 20 and $25^{\circ}C$. the growth of mycellium was not significantly af. fected by $\psi_W$ values between -1,970 and -2,240J/Kg, but severely decreased lower than -2,240J/Kg. Dry weight was slightly increased at $\psi_W$values between -450 and -2,240 J/Kg. The reduction of dry weight wasslower than the reduction of mycelial growth as the $\psi_W$ decreased. The mycelial growth and dry weight were more severely influenced on PEG amended media than on other osmotica amended media. About 50% reduction of mycelial growth and dry weight was occurred about -1,000 and -2240 J/Kg, respectively. The production of sclerotion of sclerotial production occurred between -450 and -810 J/Kg. Sclerotium was not produced lower than -2,240 J/Kg. Mycelial growth and sclerotial production was better at $25^{\circ}C$ as the $\psi_W$ decreased than at $20^{\circ}C$ which is optimal temperaturein the undmended media. The influence of $\psi_W$ on mycelial growth and sclerotial production of S. cepivorum adjusted with NaCl, KCI sucrose or polyethylene glycol showed similar patterns.

• Applied Biological Chemistry
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• v.31 no.3
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• pp.226-233
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• 1988

Some physico-chemical properties and biological activities of new fungicide formulations were tested to investigate a feasibility of water-floating formulation development for sheath blight control in rice. Pencycuron[1-(4-chlorobenzyl)-1-cyclopentyl-3-phenylurea] and flutolanil$({\alpha},{\alpha},{\alpha}$-trifluoro-3'-isopropoxy-O-toluanilide) were chosen as toxicants for the formulations. Vegetable oil and surface active agents were used as a floating agent and spreader, respectively. All the formulations tested showed an excellent spreadability on the water having over $35cm^2/mg$ and were chemically stable, which the degradation rates of active ingredients were less than 10% after 12 weeks of storage at $50^{\circ}C$. Most of the applied test formulation of pencycuron was retained within 0.5cm of the surface paddy water, while that of flutolanil was vertically dispersed in the water. Inhibition activity of the tested pencycuron formulation on the sclerotia germination of the pathogen in paddy water was maintained over 30 days after the formulation treatment. Control effect of 4% pencycuron water-floating formulated with surface active agent of hydro-lipophyllic balance 4.3 on the disease in rice was equal to the reference fungicide(pencycuron 25% WP) when the former was treated one day before the transplantation of rice seedlings. Overflowing the submerged paddy water after the formulation treatment resulted in a deterious effect on the disease control.

• Research in Plant Disease
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• v.8 no.1
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• pp.63-65
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• 2002

Red spot disease was found on broad bean (Vicia faba) in several farmer's field located in Changseon-myon, Namhae-gun, Gyeongnam provice in Korea. The typical symptoms of the disease were appeared on leaves and stems. The infection rates of the disease in the surveyed area were ranged from 16.4 to 84.6%. Lesions on the leaves were round with 1~4.2 mm in size and on the stem were narrow long fusiform with 1~15 mm in size. Conidia and conidiaphores were not readily farmed on PDA, however, a few conidia were formed on PDA added in extracts of 10 g of broad bean leaves. Conidia were light yellow green in color, globose or obovoid in shape, and 10~24$\times$8~22 $\mu$m in size. Conidiophores were cylindrical in shape, light brown in color and 3.6~12.8 $\mu$m in wide. Sclerotia of the fungus were readily formed in artificial media such as PDA. They were ellipsoid to irregular in shape, 1.2~11.8 mm in size and dark in color, The optimum temperature far growth of the fungus was about 2$0^{\circ}C$. On the basis of mycological characteristics, the fungus was identified as Botrytis fabae. This is the first report on the red spot of broad bean caused by Botrytis fabae in Korea.

• The Korean Journal of Mycology
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• v.16 no.3
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• pp.151-156
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• 1988

A leaf anthracnose disease of pepper(Capsicum annuum L.) seedling caused by Colletotrichum coccodes was found in fields of Chungnam District for the first time in 1988. Initial symptom of the disease was spotting on leaves and stems of the seedlings. The spots became sunken and gradually increased in size and coalesced to form bigger irregular spots and blights on the leaves. In severely affected fields, many pepper seedlings were defoliated and lodged. Field survey revealed that the infection rate of anthracnose ranged form 15.3% to 92.3%. Conidia from lesions on seedlings were hyaline, aseptate, straight, cylindrical with obtuse ends, $115-25(av.\;19.\;5){\times}2.5-4.8{\mu}m(av.\;3.3{\mu}m)$ and setaes were straightly extended above the acervuli, $41.3-136.3\;{\um}m(av.\;85.0{\mu}m)$ long. The fungus produced abundant sclerotia on PDA when it was cultured under darkness. In the inoculation experiments, the fungus was found to infect pepper seedlings and fruits, and fruits of tomato and egg plant.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.4
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• pp.305-311
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• 1993

Marine organisms were investigated to identify the marine actinomycetes that produced noble bioactive compounds. Microorganism counts range from $2.1{\times}10^3\;to\;1.2{\times}10\;CFU/g$ of marine organisms. Actinomycetes constituted 0.01 to $0.5\%$ of culturable microbial community. We identified the marine actinomycetes that produced novel bioactive compounds. During the course of screening for bioactives from the marine microorganisms, we found that the strain in sponge had antimicrobial activities. From the morphological, cultural and various physiological characteristics, this strain was identified for Actinomycetes No. 101. The optimal compositions of culture medium for Actinomycetes No. 101 were starch 30g/l as carbon source, casamino acid 10g/l as nitrogen source. The optimal pH of medium and fermentation temperature were $6.5{\sim}7.0$ and $30^{\circ}C$, respectively. Fermentation has been conducted in the marine broth at $30^{\circ}C$ for 72 hour. The yield of fermentation got about 3g as dry weight(per liter of broth). The distribution of antimicrobial activity of Actinomycetes No. 101 was screened by paper disc. The extract of cultured cell and broth inhibited the growth of Staphylococcus aureus and Bacillus subtilis, but the inhibition action was week against yeast and mold.

• The Korean Journal of Mycology
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• v.27 no.4 s.91
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• pp.293-298
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• 1999

An one percent sodium carbonate extract prepared from sclerotia of Poria cocos activated the proliferation of the T lymphocytes as measured by mixed lymphocyte responses(MLR). The active fraction, PCSC22, was isolated from an one percent sodium carbonate extract by a combination of fractionation procedures, including ethanol precipitation and chromatographies on column of DEAE-cellulose and Sephadex G50. Carbohydrate and peptide contained in PCSC22 were 78 : 22% in ratio. On employing gel filtration high performance liquid chromatography, PCSC22 exhitited a homogeneous peak with an average molecular weight of 8 kDa. The sugar moiety of PCSC22 was composed with mannose (92%), galactose (6.2%) and arabinose (1.3%), which might be indicated as heteromannan. Fifteen amino acids were found in peptide moiety of the polysaccharide and aspartic acid, serine, and valine were major components. PCSC22 activated the primary proliferation of T lymphocytes measured by mixed lymphocyte responses, the antibody production of the B lymphocytes and the secretion of nitric oxide from macrophage cell line, RAW264.7.

• Research in Plant Disease
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• v.12 no.2
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• pp.115-118
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• 2006

In February of 2000-2001, the gray mold disease occurred on nephrolepis (Nephrolepis sp.) grown in a flower nursery farm in Suwen, Korea. Typical symptoms were water-soaked brown or blackish lesions on terminal leaf blades. Severely infected leaves were entirely blighted with grayish fungal mycelia formed on the surface. Conidia of the fungus in mass were hyaline or gray, 1-celled, mostly ellipsoid or ovoid and $13.5{\sim}16.9{\times}6.8{\sim}9.2{\mu}m$ in size. Conidiophores were formed on PDA with $8.7{\sim}11.1{\mu}m$ in width. The sclerotia were readily formed within 2 or 3 days on PDA. In addition, the Biolog database gave the causal fungus a high similarity to Botrytis cinerea (78%) with a match probability of 100%. Pathogenicity of the causal organism was proved according to Koch's postulate. The causal organism was identified as Eotrytis cinerea based on its mycological characteristics and utilization of carbon sources with Biolog system as supporting data. This is the first report of gray mold of nephrolepis caused by Botrytis cinerea in Korea.