• 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.

• Korean Journal of Medicinal Crop Science
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• v.15 no.3
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• pp.157-161
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• 2007

To study the cause of the injury by continuous cropping and the countermeasure for reduction on it's injury in ginseng cultivation by the period passed since post-harvest, and previous soil management far planting, the injury by continuous cropping was investigated from 2004 to 2005 at the continuous cropping field of National Institute of crop Science in Jungpyong county, Korea. There was negative correlation between the ratio of survived root and the Period Passed since post-harvest. The ratio infected by Cylindrocapon destructans and Fusarium spp. in root was about 81${\sim}$95% at continuous cropping field that passed by 3${\sim}$4 years since post-harvest. Though the previous soil management for planting was somewhat effective to increase the ratio of survival root, but which was not effective to protect the infection of Cylindrocapon destructans and Fusarium spp. in root. There was no significant difference in reducing rotted root between management and nonmanagement. When previous soil management for planting was programed, it should be considered that Cylindrocapon destructans was detected at continuous cropping field that passed by above 10 years after harvesting.

• Korean Journal of Medicinal Crop Science
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• v.15 no.4
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• pp.261-265
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• 2007

A climatic feature, growth condition and incidence phase of disease and pest in Korean ginseng (Panax ginseng C. A. Meyer) were surveyed, both the conventional cultivation and culture in the forest located in Jinan. The results were as follows. The forest field was lower $1^{\circ}C$ in the air temperature, lower $1.9^{\circ}C$ in the soil temperature and 11.8% lower in the soil temperature compared with the conventional field. The wind velocity of the forest field was three times slower, but the dew condensation time was 3.3 hours longer than the conventional field. Particularly, the amounts of solar radiation in the forest was remarkably lower, while the rainfall was little lower with no significance. The incidence of disease and pest in the forest field was severe compared with that of the conventional field. Among them, Colletotrichum gloeosporioides, Cylindrocarpon destructans, and Alternaria panax was severe in the forest field while, Botrytis cinerea was severe in the conventional field. The growth condition of forest field in Panax ginseng C. A. Meyer was 50% worse in general and the root weight was 87.2% less than the 3-year-old ginseng in the conventional field.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.3
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• pp.370-376
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• 2012

Disease is the major problem in ginseng cultivation from seed stratification, soil preparation prior to planting, right through to drying of the roots. There are many soil-borne disease pathogen in rhizosphere soil environment, furthermore occurrence of diseases by a diverse group of fungi and related organisms are closely related to various soil condition. Observable symptoms for soil-borne diseases include wilting, leaf death and leaf fall, death of branches and limbs and in severe cases death of the whole plant. The fungus Cylindrocarpon destructans is the cause of root rot characterized by a decay of the true root system in many ginseng production areas in Korea. Some pathogens are generally confined to the juvenile roots whilst others are capable of attacking older parts of the root system. However, the relation between the soil environmental characteristics and ginseng root rot by soil-borne disease pathogen is not clearly identified in ginseng field. In this paper, we reviewed soil-borne plant pathogen causing root rot disease of ginseng with respect to soil environment.

• The Korean Journal of Mycology
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• v.25 no.4 s.83
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• pp.354-361
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• 1997

The antifungal activities of 153 extracts from 51 species of Korean mushroom on six phytopathogenic fungi were investigated. The powder of fruit-body of each mushroom was extracted with petroleum ether, 80% ethanol and distilled water. The water extracts of four mushrooms including Amanita virosa showed antifungal activities on Alternaria alternata, Colletotrichum graminicola, Fusarium solani, Idriella bolleyie. The 80% ethanol extracts of seven mushrooms including Boletus auripes showed antibiotic activities against A. alternata, C. gramincola, Cylindrocarpon destructans, F. solani, F. oxysporum cucumerinum, and I. bolleyie. The petroleum ether extracts of six mushrooms including Amanita citrina showed antibiotic activities against A. alternata, C. destructans, and C. graminicola. The 102 extracts of 34 mushrooms including Agaricus arvensis didn't show antibiotic activities.

• Korean Journal of Medicinal Crop Science
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• v.25 no.1
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• pp.1-9
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• 2017

Background: Some plants have harmful effects on fungi and bacteria as well as other plants. Incorporating such plant into soil as green manure is effective in reducing population densities of soil pathogens. Methods and Results: Twenty-three species of green manure crops were cultivated after the harvest of 6-year-old ginseng and then incorporated into the soil at the flowering stage. The following year, the root rot ratio of 2-year-old ginseng and soil chemical properties were investigated. In the absence of green manure addition, the $NO_3$ content, electric conductivity (EC), and K content decreased by 95%, 79% and 65%, respectively. In the presence of green manure addition, $P_2O_5$ and $NO_3$ contents reduced by 41% and 25%, respectively. The "survived root ratio" of 2-year-old ginseng significantly increased by 56.2%, 47.5%, and 47.3%, in the Sorghum sudanense, Ricinus communis and Helianthus tuberosus treatment, respectively. In addition, there was a significant increase in the "survived root ratio" in the Secale cereale, Chrysanthemum morifolium, Atractylodes macrocephala, and Smallanthus sonchifolius treatments. The "survived root ratio" of ginseng showed a significant positive correlation with the soil pH and a negative correlation with the $NO_3$ contents, and EC. Conclusions: Cultivation of plant form the Chrysanthemum family as green manure, using mainly the rhizomes was effective for the control of root rot disease of ginseng.

• Korean Journal of Medicinal Crop Science
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• v.28 no.2
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• pp.142-151
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• 2020

Background: Suppressive soil inhibits soil-borne diseases if pathogens are present, and ginseng does not show injury even if replanted in the same field. Methods and Results: Soil chemical properties and microbial community of soil were investigated in soil suppressive and conducive to ginseng root rot. Root rot disease in 2-year-old ginseng was tested by mixing conducive soil, with suppressive or sterilized suppressive soil. The root rot ratio in suppressive soil was 43.3% compared to 96.7% in conducive soil. Biological factors acted to inhibit the root rot because disease ratio was increased in the sterilized suppressive soil compared to that in non-suppressive soil. The suppressive soil had lower pH, nitrate nitrogen and sodium than the conducive soil. Dominat bacteria and fungi (more than 1.0%) were 3 and 17 species in conducive soil and 7 and 23 species in suppressive soil, respectively. The most predominant fungi were Pseudaleuria sp. HG936843 (28.70%) in conducive soil and Pseudogymnoascus roseus (7.52%) in suppressive soil. Conclusion: Microbial diversity was more abundant in the suppressive soil than in the conducive soil, and the proportion of pathogens (Nectriaceae sp.) causing root rot was significantly lower in the suppressive soil than in the conducive soil.

• The Korean Journal of Pesticide Science
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• v.16 no.2
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• pp.178-186
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• 2012

This study was investigated for the purpose of the isolation and identification of antagonistic bacteria with antifungal activity against plant pathogens. This bacteria denominated Bacillus subtilis KYS-10 and the optimum growth condition were 4% sucrose, 1% yeast extract, 0.2% $K_2HPO_4$, pH 7, 150 rpm, $30^{\circ}C$, 8 day. The antifungal activities against nine plant pathogens determined inhibition zone size by diffusion methods. The results, G. zeae (scab) 70 mm and P. grisea KACC 40439 (blast), P. capsici KACC 40177 (phytophthora blight) and C. destructans KACC 41077 (root rot of ginseng) 40~43 mm, and C. gloeosporioides KACC 43520 (ripe rot), C. gloesporioides KACC 40003 (anthracnose), S. shiraiana KACC 41065 (stem rot) and S. shiraiana (mulberry sclerotial disease) 35~39 mm and F. Oxysporum KACC 44452 (bulb rot of ginseng) 28 mm. From these experiment results, author suggest that Bacillus subtilis KYS-10 would be developed as a biological control agent thorough the field experimet in the near future.

• Korean Journal of Medicinal Crop Science
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• v.26 no.5
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• pp.345-353
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• 2018

Background: Some phenolics detected in the soil may inhibit the seed germination and seedling growth of ginseng (Panax ginseng). This study investigated the effect of irrigation and ginseng root residue addition on the soil microbial community and root rot disease in 2-year-old ginseng. Methods and Results: Each $20{\ell}$ pot was filled with soil infected with ginseng root rot pathogens, and irrigated daily with $2{\ell}$ of water for one month. After the irrigation treatment, ginseng fine root powder was mixed with the irrigated soil at a rate of 20 g per pot. In descending order, ${NO_3}^-$, electric conductivity (EC), exchangeable Na (Ex. Na) and K (Ex. K) decreased due to irrigation. In descending order, ${NO_3}^-$, EC, Ex. K, and available $P_2O_5$ increased with the additon of ginseng powder to the soil. The abundance of Trichoderma crassum decreased with irrigation, but increased again with the incorporation of ginseng powder. The abundance of Haematonectria haematococca increased with irrigation, but decreased with the incorporation of ginseng powder. The abundance of Cylindrocarpon spp. and Fusarium spp., which cause ginseng root rot, increased with the incorporation of ginseng powder. The abundance of Arthrobacter oryzae and Streptomyces lavendulae increased with irrigation. The abundance of Streptomyces lavendulae decreased, and that of Arthrobacter spp. increased, with the incorporation of ginseng powder. Aerial growth of ginseng was promoted by irrigation, and ginseng root rot increased with the incorporation of ginseng powder. Conclusions: Ginseng root residues in the soil affected soil nutrients and microorganisms, and promoted ginseng root rot, but did not affect the aerial growth of ginseng.

• Korean Journal of Organic Agriculture
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• v.23 no.4
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• pp.847-858
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• 2015

Bacillus amyloliquefaciens GR4-5 was isolated from the rhizosphere soil of Korean ginseng and displayed broad-spectrum suppression of ginseng root rot pathogens. The survivability of B. amyloliquefaciens GR4-5 in soil was investigated under three different conditions; indoor, outdoor - of which soil was put in 14 mL tube after treatment - and field environments. Soil samples were collected over a four-week period from three experimental designs, and assessed for 16S rRNA gene copy number by quantitative polymerase chain reaction (qPCR). In outdoor condition, the 16S rRNA gene copy number of Bacillus spp. was 8.35 log copies g $soil^{-1}$ immediately after the GR4-5 treatment. Two weeks later, the 16S rRNA gene copy number of Bacillus spp. (6.70 log copies g $soil^{-1}$) was similar to that of the control (6.38 log copies g $soil^{-1}$). In indoor condition, the 16S rRNA gene copy number of Bacillus spp. maintained in a certain level for a longer period than those in outdoor and field. The 16S rRNA gene copy number of Bacillus spp. in field experiment was reduced faster than that of outdoor condition. Our results show that B. amyloliquefaciens GR4-5 can survive in bulk soil for 1 week, indicating its potential use as a biocontrol agent following 7 day application intervals. This study presents that outdoor microcosm system design could be a useful method to assess easily the survivability of beneficial microorganisms.