• Journal of Ginseng Research
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• v.25 no.3
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• pp.136-140
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• 2001

Effects of incubation temperature and pH on chlamydospore germination of Cylindrocarpon destrcutans (isolate CY-9802) causing root rot of Panax ginseng were studied. Germination rate of the chlamydospores on Czapek solution agar(CSA) was higher than on potato dextrose agar(PDA) at the incubation temperatures tested. The chlamydospores were able to be germinated at range of 5$\^{C}$ to 30$\^{C}$ after 48 hours incubation on CSA. Germination rate was 53.2∼6.27% at range of 15$\^{C}$ to 25$\^{C}$, and the optimum temperature was 20$\^{C}$, whereas they were very low at 30$\^{C}$ on PDA. Germination rate was 43.6% to 47.9% at range of 10$\^{C}$ to 20$\^{C}$, and the optimum temperature was 20$\^{C}$ as well. They were able to be germinated at pH of 5.2 to 8.1 on CSA and 5.2 to 7.2 on PDA. Optimum pHs for the germination on CSA and PDA were from 6.4 to 8.2 and from 5.2 to 6.0, respectively. Mycelial color of the fungus on CSA was pale brown at pH from 5.2 to 6.0 and white from pH 6.4 to 8.1, while it was typical dark brown ar range of pH 5.2 to 7.1 and brown at pH 7.2 on PDA after 21 days incubation.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.1
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• pp.139-147
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• 2002

In order to the development of a new organic compost to exclusive use in a ginseng, we conducted the study of the preparation of organic fertilizer and the application effect of organic fertilizer in cultivation of ginseng. The new organic compost was composed of dryed broad leaves of acorn 40%, puffed husks of rice 40% and organic material mixture 20%. The chemical properties of the organic compost shown that the values of the total nitrogen, available phosphate, pottasium, calcium, magnesium, organic matter and C/N ratio were $17g\;kg^{-1}$, $8g\;kg^{-1}$, $11g\;kg^{-1}$, $14g\;kg^{-1}$, $4g\;kg^{-1}$, $794g\;kg^{-1}$, and 26.7, respectivly. The application effect of organic compost in the cultivation of ginseng shown that survival ratio of above ground plant of ginseng was shown the high value than control, and the ratio of root rot and red colored root were decreased. The optimal amount of organic fertilizer for ginseng seedling was $24M/T\;ha^{-1}$. The chemical properties of the ferilized soil were analyzed.

• 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.

• Journal of Ginseng Research
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• v.39 no.3
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• pp.213-220
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• 2015

Background: Korean ginseng (Panax ginseng Meyer) is a perennial herb prone to various root diseases, with Phytophthora cactorum being considered one of the most dreaded pathogens. P. cactorum causes foliar blight and root rot. Although chemical pesticides are available for disease control, attention has been shifted to viable, eco-friendly, and cost-effective biological means such as plant growth-promoting rhizobacteria (PGPR) for control of diseases. Methods: Native Bacillus amyloliquefaciens strain HK34 was isolated from wild ginseng and assessed as a biological control agent for ginseng. Leaves from plants treated with HK34 were analyzed for induced systemic resistance (ISR) against P. cactorum in square plate assay. Treated plants were verified for differential expression of defense-related marker genes using quantitative reverse transcription polymerase chain reaction. Results: A total of 78 native rhizosphere bacilli from wild P. ginseng were isolated. One of the root-associated bacteria identified as B. amyloliquefaciens strain HK34 effectively induced resistance against P. cactorum when applied as soil drench once (99.1% disease control) and as a priming treatment two times in the early stages (83.9% disease control). A similar result was observed in the leaf samples of plants under field conditions, where the percentage of disease control was 85.6%. Significant upregulation of the genes PgPR10, PgPR5, and PgCAT in the leaves of plants treated with HK34 was observed against P. cactorum compared with untreated controls and only pathogen-treated plants. Conclusion: The results of this study indicate HK34 as a potential biocontrol agent eliciting ISR in ginseng against P. cactorum.

• The Korean Journal of Mycology
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• v.24 no.1 s.76
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• pp.38-48
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• 1996

The survival or colonization of beneficial organsisms and suppression of root rot of ginseng (Panax ginseng) by two distinct bacteria, Pseudomonas cepacia, Bacillus cereus and three mycorrhiza in pot soil were investigated and compared with uninoculated root. In separate inoculation, colonization of roots by P. cepacia was maintained at 6.25 (log cfu/g root) during growth for 10 days under pot culture conditions comparing to $5.62{\sim}6.19$ by mixed treatment with other organisms. Colonizations of P. cepacia were gradually decreased from 6.25 (log cfu/g root) in 10 days growth to 3.01 (log cfu/g root) in 270 days incubation period. This reduction was also investgated in combination treatments by B. cereus or F. solani. The numbers of Fusarium spp. were colonized high number in rhizosphere soil from 3.33 to 3.67 (log cfu/g root) in control within $10{\sim}60$days after treatment of pathogen F. solani, but it's numbers were markedly decreased in 270 days cultivation of plant from 3.33 to 1.02 (log cfu/g root) after treatment. In treatment of beneficial strains of P. cepacia and B. cereus, P. cepacia significantly suppressed the development of root rot from 4.3 in control to 1.2 in treatment, whereas B. cereus alone had no effect on the rate of disease suppression. The disease index $(1.8{\sim}2.3)$ in combination of two bacteria was reduced in plants inoculated with both P. cepacia and B. cereus comparing to the index (4.3) of control. As an effect of inoculation with mycorrhiza on disease suppression, suppression of root rot by F. solani was reduced to $1.2{\sim}1.6$ in disease index in treatment of Glomus albidum and Acaulospora longular comparing to 4.3 of control. In the treatment of bacterial strain P. cepacia and mycorrhizal fungus Glomus albidum, the disease suppression was apparent to 1.2 and 1.2 comparing to 4.3 of control in disease index respectively.

• Journal of Ginseng Research
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• v.30 no.2
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• pp.78-81
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• 2006

Freshly harvested, immature (green) seeds of North American ginseng (Panax quinquefolius L.) were stratified for up to 3 years in plastic pails in controlled environment rooms at $5{\pm}1^{\circ}C$ for 9 months and then $21{\pm}2^{\circ}C$ for 3 months (Trt. 1, regular stratification), or continuously at $-2{\pm}0.2^{\circ}C$ (Trt. 2), or continuously at $3{\pm}0.2^{\circ}C$ (Trt. 3). During stratification at -2 and $3^{\circ}C$ embryos did not grow. On seeding in the field embryos grew rapidly and resultant seedlings were comparable to those from regularly stratified seed. Seedling emergence rate was acceptable at the industry expected rate of 68% after one year of storage, but not after two years storage when it declined to 17.5%. Seed rot was so severe in year 3 that no planting was carried out. Seedling and second year growth were similar at the three stratification temperatures; most importantly, root dry weight (economic yield) was similar. Low-temperature storage of freshly-harvested North American ginseng seed is an acceptable method for short-term retention of propagating material.

• Journal of Ginseng Research
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• v.20 no.1
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• pp.88-95
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• 1996

The effects of media, incubation time, temperature and pH on production of conidia and chlamydospore of Cylindrocarpon destructans (Zinssm.) Scholen causing root rot of Panax ginseng were studied. Microconidia of the pathogen were abundantly produced on V-8 juice agar as a solid substrate with 5.73(log conidia/mm2) and in V-8 broth as a liquid substrate with 6.65 (log conidia/ml) among media tested. No difference was observed on the length of microconidia produced from the media with a range of 9.50∼11.38 $\mu\textrm{m}$. However, tryptic soy agar produced the broadest microconidia (average 5.00 $\mu\textrm{m}$) among the media tested. All the media produced chlamydospores In a range of 1.06∼4.37 (log chlamydospores/mm2) without a significant difference in number, while V-8 juice agar produced the bigger one (18.39 $\mu\textrm{m}$ in diameter) as compared to the tested media. The fungus began to sporulate conidia after three days of incubation and reached maximum at the 8th day. It seemed to be in a stationary phase until 30 days of incubation but was decreased thereafter. Chlamydospore was produced at 4th day after incubation. Maximum production was observed at 8th day and the number seemed to be maintained during the observation period. Both conidia and chlamydospore of the pathogen were able to be spoluated at 10∼25$^{\circ}C$. However, optimum temperatures of conidia and chlamydospore formation were 15∼25$^{\circ}C$ and 10∼20$^{\circ}C$, respectively. C. destrmtans produced conida with an wide range of pH from 3.3 to 8.0 and chlamydospore from 2.8 to 8.0. Number of conidia was increased with an increase of pH up to 4.0. There was no significant difference in the number between 4.0 to 8.0. It seemed to have two optimum pH ranges, 3.3∼4.0 and 7.1∼8.0 for the chlamydospore formation.

• The Korean Journal of Mycology
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• v.13 no.1
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• pp.41-47
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• 1985

Eighteen plant residues were added to soil and the amended soil was inoculated with chlamydospores (5,000 cells/g soil) of Fusarium solani causing root rot of ginseng in soil to test the effects of amendment using pea (Pisium sativa L.) as an index plant. Distributional conditions of microogranisms in soil were compared with each other before and after dealing with soil amendment by plant debries. Infection rate by index plant's infectivity showed a higher degree in the treatment of wheat crushed than in control group, and followed by stalk of sweet potato, chinese cabbage, ginseng leaves and soybean pod. On the other hand, the de­creasing order of infection rate was root of garlic, welsh onion, cabbage leaf and stalk, green onion stalk, wheat straw and barley straw. In comparison with control group, the propagules of fungi increased in the treatment of ginseng leaves, soybean ground, wheat crushed, maize stalk, and chinese cabbage, but decreased in the root of garlic, cabbage, and barley straw. Population of total bacteria increased in the treatment of soybean ground, chinese cabbage, radish stalk, welsh onion, and wheat crushed, but decreased in barley straw, tobaco root, ginseng stalk, and wheat straw. The numbers of actinomycetes increased only in the treatment of soybean ground in a comparison with control and also decreased in the garlic stalk and tobaco root. The propagules of Fusarium spp increased in the treatment of chinese cabbage, welsh onion, radish stalk, wheat crushed, and sweet potato stalk, wheat crushed, and sweet potato stalk, but decreased in the treat­ment of wheat straw, ginseng leaves, and cabbage than control.

• Research in Plant Disease
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• v.10 no.4
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• pp.248-259
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• 2004

A total 115 isolates of Fusarium species from ginseng roots of 'rotted', and soils collected during 1982-1985 in Korea, were identified and classified into 11 species with the Snyder & Hansen System (with reference to Gerlach-Nirenberg's Modified System). The most dominant of these species were F. solani (55 isolates), F. oxysporum (35 isolates), and F. moniliforme (10 isolates) sensu Snyder & Hansen. The other 8 species (15 isolates) were very rarely isolated and previously identified as F. roseum sensu Snyder & Hansen (1945); these were F. equiseti, F. avenaceum, F. graminum, F. arthrosporioides, F. sambucinum, F. reticulatum, F. semitectum and F. poa. Tested for the ability to infect the roots of ginseng (3 yr. old plants) in field condition with the mycelial inoculum, only one isolate of F. solani (34 isolates tested) and one isolate of F. oxysporum (24 isolates tested) were weakly pathogenic to ginseng roots. Any of the isolates (7 isolates tested) of F. moniliforme [Liseola section] were not pathogenic to ginseng. However, all the isolates of tested of the species of Phytophthora cactorum, Pythium ultimum, and Cylindrocarpon destructans were highly pathogenic to ginseng roots. The species of Fusarium solani and Cylindrocarpon destructans were supposed to be a host dominant disease agent in ginseng plant.

• Journal of Ginseng Research
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• v.40 no.2
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• pp.97-104
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• 2016

Background: Rhizobacteria play an important role in plant defense and could be promising sources of biocontrol agents. This study aimed to screen antagonistic bacteria and develop a biocontrol system for root rot complex of Panax notoginseng. Methods: Pure-culture methods were used to isolate bacteria from the rhizosphere soil of notoginseng plants. The identification of isolates was based on the analysis of 16S ribosomal RNA (rRNA) sequences. Results: A total of 279 bacteria were obtained from rhizosphere soils of healthy and root-rot notoginseng plants, and uncultivated soil. Among all the isolates, 88 showed antagonistic activity to at least one of three phytopathogenic fungi, Fusarium oxysporum, Fusarium solani, and Phoma herbarum mainly causing root rot disease of P. notoginseng. Based on the 16S rRNA sequencing, the antagonistic bacteria were characterized into four clusters, Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetesi. The genus Bacillus was the most frequently isolated, and Bacillus siamensis (Hs02), Bacillus atrophaeus (Hs09) showed strong antagonistic activity to the three pathogens. The distribution pattern differed in soil types, genera Achromobacter, Acidovorax, Brevibacterium, Brevundimonas, Flavimonas, and Streptomyces were only found in rhizosphere of healthy plants, while Delftia, Leclercia, Brevibacillus, Microbacterium, Pantoea, Rhizobium, and Stenotrophomonas only exist in soil of diseased plant, and Acinetobacter only exist in uncultivated soil. Conclusion: The results suggest that diverse bacteria exist in the P. notoginseng rhizosphere soil, with differences in community in the same field, and antagonistic isolates may be good potential biological control agent for the notoginseng root-rot diseases caused by F. oxysporum, Fusarium solani, and Panax herbarum.