• Proceedings of the Korean Society of Plant Pathology Conference
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• 2002.11a
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• pp.93.1-93
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• 2002

• Korean Journal of Plant Resources
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• v.19 no.3
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• pp.436-439
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• 2006

This study was carried out to obtain basic information for optimum storage method of leaf, stem and root of Angelica acutiloba Radix, which is being utilized as major cultivated herbal medicine materials, root of Angelica acutiloba was stored for 3 months in different packing materials and sealing methods, such as punched packing, sealing and vacuum packing. The results are summarized as follows. The loss in weight as influenced by packing materials and sealing degree was the lowest at vacuum packing and complete sealing condition with transparent polyethylene film. The ratio of root rot during the storage period was not significantly different between polyethylene films, but it was significantly different between sealing conditions. Therefore, vacuum packing and complete sealing with polyethylene film are desirable storage condition for Angelica acutiloba Radix.

• Journal of Korea Foresty Energy
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• v.20 no.1
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• pp.1-5
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• 2001

In this study, it was examined the effect of carbonized wastewoods on soil improvement and effect of charcoal size on tree seedling growth Thuja accidentalis seedlings grow better in the charcoal-treated soil than in the non-treated soil. Especially Pinus koraiensis charcoal with good adsorption. brought the best growth result. The charcoal treatment also improved the height growth of transplanted Aesuculus turbinate seedling However charcoal sizes(i.e. powder and particle) did not affect the growth of the seedling. Also apple trees which had been suffering from rotten roots caused by root rot was recovered by application particle-sized charcoal.

• The Plant Pathology Journal
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• v.18 no.2
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• pp.57-62
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• 2002

In vivo expression technology (IVET) has been developed to study bacterial gene expression in Salmonella typhimurium during host infection. The expression of selected genes by IVET has been elevated in vivo but not in vitro. The selected genes turned out to be important for bacterial virulence and/or pathogenicity. IVET depends on a synthetic operon with a promoterless transcriptional fusion between a selection marker gene and a reporter gene. The IVET approach has been successfully adapted in other bacterial pathogens and plant-associated bacteria using different selection markers. Pseudomonas putida suppresses citrus root rot caused by Phytophthora parasitica and enhances citrus seedling growth. The WET strategy was adapted based on a transcriptional fusion, pyrBC'-lacZ, in P. putida to study the bacterial traits important far biocontrol activities. Several genes appeared to be induced on P. parasitica hyphae and were found to be related with metabolism and regulation of gene expression. It is likely that the biocontrol strain took a metabolic advantage from the plant pathogenic fungus and then suppressed citrus root rot effectively. The result was parallel with those from the adaptation of IVET in P. fluorescens, a plant growth promoting rhizobacteria (PGPR). Interestingly, genes encoding components for type III secretion system have been identified as rhizosphere-induced genes in the PGPR strain. The type III secretion system may play a certain role during interaction with its counterpart plants. Application of IVET has been demonstrated in a wide range of bacteria. It is an important strategy to genetically understand complicated bacterial traits in the environment.

• Korean Journal Plant Pathology
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• v.10 no.3
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• pp.175-180
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• 1994

The fungal pathogen Monosporascus annonballus was first isolated in Korea from the rotted roots of bottle gourd stocks of collapsed watermelon plants in fields near Chochiwon, Choongnam province in July, 1993. Perithecia of M. cannonballus were dark brown to black, globose, 220~570 ${\mu}{\textrm}{m}$ in diam. and had many asci. Asci are hyaline, clavate to pyriform, and 50~120$\times$35~570 ${\mu}{\textrm}{m}$ in size. Ascospores were aseptate, dark brown to black, globose, 25~45$\times$30~50 ${\mu}{\textrm}{m}$ in diam, and borne singly in each ascus. The fungus grew in the temperature range of 4 to 34$^{\circ}C$, best at 3$0^{\circ}C$. The optimum pH for growth was 6.8. Mycelial growth rate of M. cannonballus was 25.5mm/day on PDA at 26$^{\circ}C$. Perithecia began to form after 20-day-growth on PDA and produced mature asci after 30 days or later. In the greenhouse inoculation tests, the fungus developed water-soaked lesions on roots of bottle gourd seedlings and was then reisolated from the lesions. Severed damages on watermelon plants by M. cannonballus are greatly concerned in Korea, since no stocks used for watermelon cultivation have reported to be resistant to the fungus.

• Current Research on Agriculture and Life Sciences
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• v.23
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• pp.33-41
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• 2005

Above 130 accessions of pepper consisting of 50 introductions from Mexico and Nepal, and resistant and susceptible controls were tested for resistance to bacterial wilt and to Phytophthora root rot at seedling stage by artificial inoculation. Aa the results, KC897, KC939, KC936 were newly found resistant to bacterial wilt in addition to already known resistance sources such as KC126, KC350, KC351, KC353. No new sources of resistance to Phytophthora root rot were found among the introductions from Mexico and Nepal.

• Mycobiology
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• v.43 no.1
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• pp.63-70
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• 2015

Phytophthora diseases have become a major impediment in the citrus production in Thailand. In this study, an isolate of Phytophthora denominated as PHY02 was proven to be causal pathogen of root rot of Pomelo (Citrus maxima) in Thailand. The isolate PHY02 was morphologically characterized and identified as Phytophthora palmivora based on molecular analysis of an internal transcribed spacer rDNA sequence. This work also presents in vitro evaluations of the capacities of Chaetomium spp. to control the P. palmivora PHY02. As antagonists, Chaetomium globosum CG05, Chaetomium cupreum CC3003, Chaetomium lucknowense CL01 inhibited 50~61% mycelial growth, degraded mycelia and reduced 92~99% sporangial production of P. palmivora PHY02 in bi-culture test after 30 days. Fungal metabolites from Chaetomium spp. were tested against PHY02. Results showed that, methanol extract of C. globosum CG05 expressed strongest inhibitory effects on mycelial growth and sporangium formation of P. palmivora PHY02 with effective dose ED50 values of $26.5{\mu}g/mL$ and $2.3{\mu}g/mL$, respectively. It is interesting that C. lucknowense is reported for the first time as an effective antagonist against a species of Phytophthora.

• Korean Journal Plant Pathology
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• v.13 no.1
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• pp.30-36
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• 1997

The effects of carbon and nitrogen sources on the mycelial growth and sporulation of microconidia and chlamydospores of five isolates of Cylindrocarpon destructans (Zinssm.) Scholten causing root rot of Panax ginseng were studied. For the carbon sources, fructose, glucose, maltose, and sucrose in Czapek-Dox broth showed good mycelial growth of 178∼201 mg in dry weight compared with 64 mg of the control. The best carbon sources tested for conidial formation were sucrose and maltose with 2.75 and 3.03 log conidia/ml, respectively. For the nitrogen sources, aspartic acid, NaNO3, KNO3, arginine, threonine, and leucine increased mycelial growth of the fungi to 208∼231 mg in dry weight without significant difference (p=0.05) among them. Meanwhile the growth with cystine was poor (26.3 mg dry weight), and no conidium and chlamydospore were formed. Maximum microconidial formation was observed in the media with NaNO3 and KNO3 as 3.37 and 3.35 log conidia/ml, and for the chlamydospore formation the (NH4)2SO4-containing medium and the nitrogen-absent medium were the best as 3.40 and 3.57 log chlamydospores/ml, respectively. No conidium was found in the medium without nitrogen sources, in which chlamydospore formation increased 6 times more than in the nitrogen-amended medium. However, deletion of carbon source in the medium did not affect on the formation of conidia and chlamydospores of C. destructans.

• Korean Journal Plant Pathology
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• v.13 no.2
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• pp.100-104
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• 1997

Influence of the moisture content in soils was examined on population variations of soil microbes, including Cylindrocarpon destructans causing root rot of ginseng, in vivo and under the field condition. Fungal populations decreased in soils treated with various moisture contents in vivo as days after the treatment in creased, but there was not a significant difference in the population among other treatments except 135% moisture content (flooding) at 15 weeks after the treatment. In flooded soils populations of total fungi and C. destructans were reduced to 1/10 and 1/50 of initial populations, respectively. There was, however, a little difference in the population of total bacteria or Actinomycetes between before and at 15 weeks after flooding. On the other hand, population variations of bacteria and Actinomycetes were much greater than those of fungi at different intervals after the moisture treatment. Variations of microbial populations in flooded soils under the field condition were similar to those in vivo. Especially, populations of Fusarium and pectolytic bacteria in flooded soils were reduced to 1/100 of populations in nonflooded soils at 170 days after treatment.

• Mycobiology
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• v.45 no.3
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• pp.220-225
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• 2017

Ginseng root rot caused by Cylindrocarpon destructans is the most destructive disease of ginseng. Six different fungicides (thiophanate-methyl, benomyl, prochloraz, mancozeb, azoxystrobin, and iprodione) were selected to evaluate the inhibitory effect on the mycelial growth and conidial germination of C. destructans isolates. Benomyl and prochloraz were found to be the most effective fungicides in inhibiting mycelial growth of all tested isolates, showing 64.7% to 100% inhibition at a concentration of $10{\mu}g/mL$, whereas thiophanate-methyl was the least effective fungicide, showing less than 50% inhibition even at a higher concentration of $100{\mu}g/mL$. The tested fungicides exhibited less than 20% inhibition of conidium germination at concentrations of 0.01, 0.1, and $1{\mu}g/mL$. However, the inhibition effect of mancozeb on condium germination of C. destructans was significantly increased to 92% to 99% at a higher concentration of $100{\mu}g/mL$, while the others still showed no higher than 30% inhibition.