• Proceedings of the Ginseng society Conference
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• 1978.09a
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• pp.67-74
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• 1978

The phenomenon of 'soil sickness' is one of the most important limiting factors for ginseng(Panax ginseng) production in Korea. The principal cause is known to be due to the root rots caused by Cylindrocarpon destructans and Fusarium solani. Attempts were made to control the root rots with non-polluting cultural methods or soil amendments. Among the nine soil amendments tested, crab shell, cow bone and pig feces were selected for further testing. Each of the three amendments increased the populations or various actinomycetes in the range of 10-25 times over that of non-amended soil, whereas the population of C. destructans was reduced to about $50-70\%$ as compared with the control. Five isolates of Streptomyces with clear zones on chitin-agar medium were selected and then tested for their antagonistic effects on C. destructans. When anyone of the five isolates of Streptomyces and C. destructans was grown together in a modified peptone broth, growth of the latter was highly inhibited. When three levels of crab shell, cow bone, or pig feces were used to amend potted soil infested with C. destruetans, the root rot ratings of ginseng seedlings were reduced to less than one half in all the treatments as compared to the control. In another similar experiment, crab shell and cow bone amendments resulted in almost complete control of the seedling root rots in soil infested with C. destructans or F. solani. In conclusion, biological control with soil amendments of ginseng root rots caused by C. destructans and F. solani was successful. Further basic studies should be pursued using soil amendments for better control. In addition, field experiments are needed to complement the soil amendment control measures in an integrated pest control program.

• International Journal of Industrial Entomology and Biomaterials
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• v.39 no.2
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• pp.82-85
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• 2019

We investigated the anti-microbial activity of propolis against the pathogenic bacteria and fungi on ginseng. We selected six microbials that caused postharvest root rots in ginseng. Propolis extracts were prepared by using the ethanol extraction method. We seeded the bacteria and fungi related to ginseng disease on a specific culture medium, and treated it with propolis extracts by using the paper disc method. Propolis extracts indicate the anti-microbial activity against Paenibacillus polymyxa, Fusarium solani, Rhizoctonia solani AG-1 and Pythium ultimum. However, the anti-fungal activity of propolis is weak on Pseudomonas fluorescens subsp. Cellulosa and Colletotrichum gloeosporioides. As a result, the antimicrobial effects of propolis against microbial that prevent ginseng growth were confirmed. The antimicrobial effects are shown according to the concentration of propolis against root rot. The fungi also showed antibacterial effects in a dose-dependent manner.

• Korean Journal of Medicinal Crop Science
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• v.26 no.3
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• pp.248-253
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• 2018

Background: Dazomet are widely used as soil fumigant to solve soilborne problems, and the degradation intermediates are toxic to nematodes, fungi, bacteria, insects and weeds. Methods and Results: The effects of cultivation of green manure crop, maize before and after soil fumigation on the control of ginseng root rot disease were compared using soil where 6-years-old ginseng was harvested. Fumigant (dazomet) were used for soil fumigation in May and September, respectively. Maize was grown for soil management before and after soil fumigation. After May fumigation, the sowing date of maize was delayed by 15 days and thus its dry weight was decreased significantly. Maize cultivation after May fumigation increased pH but decreased EC, $NO_3$, $P_2O_5$, and K significantly. Maize cultivation after May fumigation decreased fungi population and the ratio of fungi and bacteria. Growth of 2-years-old ginseng was improved and the incidence of ginseng root rot was significantly decreased by maize cultivation after May fumigation. After harvesting 2-years-old ginseng, the population of Cylindrocarpon destructans was not different between treatment of May and September, but Fusarium solani showed a significant increase in September fumigation after maize cultivation. Conclusions: Maize cultivation after soil fumigation was effective in inhibiting ginseng root rot by the amendment of mineral composition and microorganism in fumigated soil.

• The Plant Pathology Journal
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• v.17 no.3
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• pp.141-148
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• 2001

Postharvest decay of onion bulbs was examined by inspecting the commercial packages in the market or in storage. Bulb rot incidence was unexpectedly high, and onion bulbs with 1st quality grade were rotten most severely by 51%, followed by 32% for 2nd and 21% for 3rd grades. This indicates that larger bulbs had higher incidences of bulb rots. Major pathogens associated with basal and neck rots were Fusarium oxysporum and Aspergillus sp. or Botrytis allii, respectively, of which basal rot was most prevalent and damaging during storage. Among the epiphytic microorgani는 from onion plants, several Bacillus and Paenibacillus spp. and previously selected Pseudomonas putida and Trichoderma harzianum had inhibitory efficacy against bulb rot pathogens. Among these B. amyloliquefaciens BL-3, Paenibacillus polymyxa BL-4, and P. putida Cha 94 were highly inhibitory to conidial germination of F. oxysporum and B. allii. P. putida Cha 94, B. amyloliquefaciens BL-3, P. polymyxa BL-4, and T. harzianum TM were applied in the rhizoplane of onion at transplanting. Initially antagonist populations decreased rapidly during the first one month. However, among these antagonists, rhizoplane population densities of BL-3, Cha 94, and TM were consistently high thereafter, maintaining about 10$^4$-10$^{5}$ cells or spores per gram of onion root up to harvest time. The other bacterial antagonist BL-4 survived only for two months. TM was the most effective biocontrol agent against basal rot, with the number of rotten bulbs recorded at 4%, while that of the control was 16%. Cha 94 was effective for the first 20 days, but basal rot increased thereafter and had about the same control efficacy as that of BL-3 and BL-4. When the antagonists were applied to the topping areas of onion bulbs at harvest, TM was the most effective in protecting the stored onion bulbs from neck rotting. The second effective antagonist was BL-3. TM and BL-3 completely suppressed the neck rot in another test, suggesting that biocontrol of postharvest decay of onion using these microorganisms either at the time of transplanting or at harvesting may be promising.

• Korean Journal of Microbiology
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• v.42 no.2
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• pp.135-141
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• 2006

We isolated a bacterium which produces antifungal substances from the Sanktpeterburg soils at Russia. The iso-lated strain was identified as Brevibacillus sp. and shown a strong antifungal activity on plant pathogenic fungi. Brevibacillus sp. KMU-391 produced maximum level of antifungal substances under incubation aerobically at $30^{\circ}C$ for 48 hours in trypticase soybean broth containing 1.0% sucrose and 1.0% polypeptone at 180 rpm and initiated pH adjusted to 7.0. Precipitate of culture broth by $30{\sim}60%$ ammonium sulfate precipitation exhibited strong antifungal activity against Didymella bryoniae by dry cell weight. Butanol extract of cultured broth also shown fungal growth inhibitory activity against Botrytis cinerea KACC 40573, Botrytis fabae KACC 40962, Colletotrichum gloeosporioides KACC 40804, Colletotrichum orbiculare KACC 40808, Didymella bryoniae KACC 40669, Fusarium graminearum KACC 41040, Fusarium oxysporum KACC 40037, Fusarium oxysporum KACC 40052, Fusarium oxysporum f, sp. radicis-Iycopersici KACC 40537, Fusarium oxysporum KACC 40902, Monosporascus cannonballus KACC 40940, Phytophthora camvibora KACC 40160, Rhizoctonia solani AG-1(IA) KACC 40101, Rhizoctonia solani AG-4 KACC 40142, and Scleotinia scleotiorum KACC 41065 by agar diffusion method.

• Journal of Microbiology and Biotechnology
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• v.12 no.2
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• pp.249-257
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• 2002

Pseudomonas fluorescens GL20 is a plant growth-promoting rhizobacterium that produces a large amount of hydroxamate siderophore under iron-limited conditions. The strain GL20 considerably inhibited the spore germination and hyphal growth of a plant pathogenic fungus, Fusarium solani, when iron was limited, significantly suppressed the root-rot disease on beans caused by F. solani, and enhanced the plant growth. The mechanism for the beneficial effect of strain GL20 on the disease suppression was due to the siderophore production, evidenced by mutant strains derived from the strain. Analysis of the outer membrane protein profile revealed that the growth of strain GL20 induced the synthesis of specific iron-regulated outer membrane proteins with molecular masses of 85- and 90 kDa as the high-affinity receptors for the ferric siderophore. In addition, a cross-feeding assay revealed the presence of multiple inducible receptors for heterologous siderophores in the strain. In order to induce increased efficacy and potential in biological control of plant disease, a siderophore-overproducing mutant, GL20-S207, was prepared by NTG mutagenesis. The mutant GL20-S207 produced nearly 2.3 times more siderophore than the parent strain. In pot trials of beans with F. solani, the mutant increased plant growth up to 1.5 times compared with that of the parent strain. These results suggest that the plant growth-promoting P. fluorescens GL20 and the genetically bred P. fluorescens GL20-S207 can play an important role in the biological control of soil-borne plant diseases in the rhizosphere.

• The Plant Pathology Journal
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• v.21 no.4
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• pp.317-321
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• 2005

Since 2000 severe rots on aerial and underground parts of paprika (Capsicum annum L.) has occurred in most surveyed glasshouses throughout the country. A total of 56 isolates of a fungus were consistently isolated from various plant parts such as fruit, stem, branch, and root collected from 16 farms in five provinces. Anamorph stage of the fungus was identified as Fusarium solani based on its morphological characteristics. However, the fungus readily produced a sexual structure of perithecia on infected plant tissues and on agar media. Since the fungus formed abundant perithecium by a single isolate, it was considered as a homothallic strain of Nectria haematococca, the teleomorph of F. solani. Irregularly globose perithecia with orange to red color formed sparsely to gregariously on dead tissues of fruits and basal stems at the late infection stage, which is a diagnostic sign for the disease. Perithecia ranged from 125 to 220 ${\mu}m$ in diameter varied among isolates. Asci enveloping eight ascospores were cylindrical and measured 60-80x8-12 ${\mu}m$. Ellipsoid to obovate ascospores are two-celled and measured 11-18x4-7 ${\mu}m$. Ascospores were hyaline, slightly constricted at the central septum, and revealed longitudinal striations that is characteristic of the species. This fungus that has never been reported in Korea has previously become a threat to paprika cultivation because of its strong pathogenicity and nationwide distribution.

• Horticultural Science & Technology
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• v.29 no.3
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• pp.273-277
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• 2011

Fusarium oxysporum f. sp. fragariae (Fof), the causal agent of crown and root rot in strawberry, is the most serious soilborne disease of nursery plants in Korea. The possibility of infection by Fof through runner propagation from infected mother plants of strawberry cv. 'Kumhyang' was assessed in stolons and daughter plants hanging from raised beds. The number of daughter plants from an infected mother plant in plastic house and photosynthetic photon flux (PPF) system, 280 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ was 2.7 and 3.8 plants after 58 days, respectively. However, healthy mother plants produced 6.5 and 8.4 daughter plants, respectively. The pathogen was detected in the uppermost portion of the stolon after 58 days, but was not detected further down the stolon. After 90 days, it was detected in all portions of the stolon between mother and $1^{st}$ daughter plant and in 60% of all $1^{st}$ daughter plants. The pathogen was not detected in the corresponding portions of the non-infected controls. These results show that infected mother plants can transmit Fof to their daughter plants without passing through the soil and $1^{st}$ daughter was used as mother plant in PPF system for propagating healthy plants.

• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.396-403
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• 2014

Ginseng (Panax ginseng C. A. Meyer) is an economically valuable pharmaceutical crop in Korea. In order to find promising biocontrol agents for soil-borne fungal pathogens which infect ginseng roots, we have isolated actinomycete, BK185 from soil. The isolate was investigated for the antifungal activity against to ginseng rot pathogens prior to testing genetic and chemical properties. The strain was identified as Streptomyces sp. using phylogenetic analysis based on 16S rRNA gene sequence. The most closely related species was S. sporoclivatus and S. geldanamycininus with high similarities (>99%). The isolate, BK185 showed positive reaction for PCR detection targeting biosynthetic gene clusters of PKS (Type-I polyketide synthase) and NRPS (Non-ribosomal polypeptide synthetase) genes. Major metabolite from the BK185 was analyzed by The LC/MS and identified to geldamycin, which was known to contained broad antibacterial, antifungal or anticancer activities. The results provide evidences that the strain, BK185 can be promising biocontrol agent for ginseng organic farming.

• The Korean Journal of Mycology
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• v.22 no.1
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• pp.50-61
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• 1994

From soil samples, 380 antagonistic microorgnisms were isolated. Among the isolates, 42 strains had mycelia growing inhibition ability against Fusariun solani, ginseng root rot causing pathogen. Isolates CHA 1 and S-PFHR 6 were proposed as antagonists for this study and they were identified as Promicromonospora sp. and Pseudomonas pseudoalcaligenes respectively. As an antagonism against hyphae of F. solani in dual culture test, CHA 1 and S-PFHR 6 inhibited linear growing, caused abnormal branching, and the membrane projection which formed by cell wall destruction. The secondary metabolites contained in the culture filtrates which prepared from PD broth and Nutrient broth inhibited the spore germination to 14.3%. The culture filtrate of S-PFHR 6 which prepared by a little amount of soil extract addition to nutrient rich medium had more strongly. inhibited the spore germination and spore germination decreased to less than 4.0% in it. The soil used in this study had fungistasis and the germination rate of macroconidia and chlamydospore of F.solani was 19.4% and 17.7% respectively. The steam sterilized soil lost fungistasis and germination rate of conidia increased to more than 97.9%. The soils amended with the propagule of CHA 1 and S-PFHR 6 increased fungistasis and the germination rate of macroconidia decreased to 14.7% and 11.7% respectively in each treatments. But the soil ammended with glucose and asparagine annulled fungistatic ability and the germination rate of macroconidia increased to more than 48.0%. As an antagonistic activity of the secondary metabolites of two antagonistic isolates in soil, the germination rate of macroconidia of F. solani was 9.3% in the soil amended with the culture filtrate of CHA 1 but the culture filtrate of S-PFHR 6 had no such activity. In the soil which treated with antagonist propagule or culture filtrate, the chlamydospore germination rate was lower than that in natural soil. The addition of glucose and asparagine to antagonist propagule treated soil did not enhanced the chlamydospore germination.