• The Korean Journal of Ecology
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• v.15 no.3
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• pp.297-309
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• 1992

The growth of digitaria adscendens and eleusine indica, annual weeds common in japan, was experimentally analyzed under varying untrient conditions. compared with e. indica, d. adscendensshowed a higher the two under high nitrogen availability. Higher net assimilation rate(nar) in d. adscendens than e. india was responsible for high RGR in D. adscendens under the low nitrogen availability. The different of NAR in the two species was induced not by leaf nitrogen content but by nitrogen use efficiency. Under unfertilized conditions nitrogen uptake rate(nur) was greater in d. adscendens than e. indica. Specific absorption rate in two species was similar, but root mass was greater in d. adscendens than e. indica.d. adscendens allocated more dry matter to roots than e. india earlier stage of seedlings. The contributed to higher rot mass and in turn resulted in higher nur in d. adscendens than that in e. india. It is concluuded that the larger allocation of dry matter to roots at early seedling stage in d. adscendens plays an important role in obtaining nitrogen for the continuation of growth under low nitrogen availability.

• Journal of Ginseng Research
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• v.4 no.2
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• pp.186-193
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• 1980

The causal organism of Phytophthora disease on Panax ginseng Meyer in Korea was isolated and identified as Phytophthora cactorum. It's pathogenicity, etiology, and possible control measures were investigated. Disease symptoms on various parts of ginseng plants were also described The fungus caused seedling and mature plant blight and root rot. Oospores were easily formed on potato dextrose agar and corn meal agar. Oospores, however, were not formed in the diseased root tissues but did in the in footed shoots such as leaves, petioles, and stems and in the inoculated berries.

• Korean Journal of Microbiology
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• v.12 no.2
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• pp.94-98
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• 1974

This study was conducted from April 1 to September 31, 1973. Ten strains of Fusarium spp. were isolated from the diseased ginseng in two local areas at Kangwha-Gun nad Kumsan-Gun in Korea. Among of them, 2 strains ($G_1$, $G_4$) did not have virulence to ginseng in reinoculation. Their cultural, morphological characteristic and hose virulence to pea seedling were examined. Taxonomical identification of 8 isolates followed by the method of Wollenweber, Snyder nad Toussoun, Booth, Matuo and Snyder. All of eight strains were identified as the Fusarium solani f.sp.pisi(Jones) Synd. et Hans.

• Journal of Bio-Environment Control
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• v.9 no.3
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• pp.146-150
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• 2000

This study was conducted to investigate the effect of seedling age on quality and yield in bag culture of sweet pepper. Seedlings of 20, 30, 40, 50, and 60 days old were compared. 60 days old seedlings grew faster than 30 or 40 days old seedlings. Mean days to bloom after sowing was fastest as 48 days in 30 days old seedling, followed by 20 days old seedlings. Rot activity was higher in 20 or 30 days old seedlings. Number and length of first lateral roots with thickness of 1.5mm or less, reached to 106.5 and 1.085 cm, respectively in 30 days old seedlings. Root weight, root length, and number of primary lateral roots were the greatest in 30 days old seedling. Greater early yield a obtained in 50 and 60 days old seedling, while late yield was grater in 30 or 40 days old seedlings.

• The Plant Pathology Journal
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• v.20 no.1
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• pp.63-66
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• 2004

Ginseng (Panax ginseng) is one of the most widely cultivated medicinal herbs in Korea. However, yield losses reached up to 30-60％ due to various diseases during 3 or 5 years of ginseng cultivation in the country. Therefore, successful production of ginseng roots depends primarily on the control of diseases. The objective of this study was to select potential biocontrol agents from rhizobacteria isolated from various plant internal root tissues for the control of multiple ginseng diseases as an alternative to fungicides. Among 106 Bacillus strains, two promising biocontrol agents, Bacillus pumilus strain B1141 and Paenibacillus lentimobus strain B1146, were selected by screening against root rot of ginseng caused by Cylindrocarpon destructans in a greenhouse. Pre-inoculation of selected isolates to seed or l-year-old root of ginseng resulted in stimulation of shoot and/or root growth of seedlings, and successfully controlled root rot caused by C. destructans (P<0.05). Furthermore, drenching of cell suspension of the selected isolates on seedling-growing pots reduced the incidence of Phytophthora blight after the seedlings were challenged with zoospores of Phytophthora cactorum (P<0.05). P. lentimorbus strain B1146 showed antifungal activity against various soil-borne pathogens in vitro, while B. pumilus strain B1141 did not show any. Results of this study suggest that some rhizobacteria can induce resistance against various plant diseases on ginseng.

• Current Research on Agriculture and Life Sciences
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• v.17
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• pp.7-13
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• 1999

Thirty bacteria were isolated from the red pepper rhizosphere. The isolates were screened for antagonism to Alternaria alteranta causing red pepper black rot. Antagonistic bacterium No. J-24 was selected among the isolated bacteria and was identified as Bacillus subtilis based on morphological and physiological characteristics and MIDI system. B. subtilis J-24 showed antifungal activities against A. alternata(inhibition percentage, 99%), Botrytis cinerea, Phytophthora capsici, Pythium ultimum, Colletotrichum gloeosporioides, Stemphylium botryosum. The growth of red pepper seedling was promoted as compared to control when the microbial inoculants was mixed in bed soil. In the mixed microbial inoculants bed soil, the leaf area of red pepper was increased of 15 percent, the hypocotyl weight 12 percent, the root length 12 percent, total dry weight 13 percent as compared to those grown in the general bed soil.

• Korean journal of applied entomology
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• v.20 no.4 s.49
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• pp.183-190
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• 1981

Alternaria sesami, A. sesamicola, A. tenuis, A. longissima, Cercospora sesami, Cephalosporium sp., Corynespora cassiicola, Fusarium equiseti, F. moniliforme, F. oxysporum, F. semitectum, Macrophomina phaseolina and Myrothecium roridum were detected from 40 seed samples of sesame. A sesami, A. sesamicola, A. tenuis and C. cassiicola were the predominant fungi. Except C. cassiicola, all fungi were almost completly reduced and wiped out the infection by pretreatment with chlorine. Plating components also indicate that C. cassiicola was well-established infections. Seedborne infection of C. cussiicola caused heavy seed rot and seedling mortality. Detailed description has been given on the habit character of C. cassiicola under stereoscopic microscope and the variation in colony character and spore morphology have been taken into account. In inoculation experiments, C. cassiicola produced severe leaf and stem spots and blights on sesame plants resulted in ultimate death of the plants. A. sesami, A. sesamicola A. longissima and C. sesami also produced mild to severe leaf spotting and leaf blight when suspension of their conidia were sprayed on to plants. In soil inoculation experiments, F. oxysporum and M. phaseolina were the most pathogenic causing seed rot and seedling blight.

• The Plant Pathology Journal
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• v.34 no.5
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• pp.393-402
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• 2018

Rice world production is affected due to the growing impact of diseases such as bacterial panicle blight, produced by Burkholderia glumae. The pathogen-induced symptoms include seedling rot, grain rot and leafsheath browning in rice plants. It is currently recognized the entrance of this pathogen to the plant, from infected seeds and from environmental sources of the microorganism. However, it is still not fully elucidated the dynamics and permanence of the pathogen in the plant, from its entry until the development of disease symptoms in seedlings or panicles. In this work it was evaluated the infection of B. glumae rice plants, starting from inoculated seeds and substrates, and its subsequent monitoring after infection. Various organs of the plant during the vegetative stage and until the beginning of the reproductive stage, were evaluated. In both inoculation models, the bacteria was maintained in the plant as an endophyte between $1{\times}10^1$ and $1{\times}10^5cfu$ of B. $glumae.g^{-1}$ of plant throughout the vegetative stage. An increase of bacterial population towards initiation of the panicle was observed, and in the maturity of the grain, an endophyte population was identified in the flag leaf at $1{\times}10^6cfu$ of B. $glumae.g^{-1}$ fresh weight of rice plant, conducting towards the symptoms of bacterial panicle blight. The results found, suggest that B. glumae in rice plants developed from infected seeds or from the substrate, can colonize seedlings, establishing and maintaining a bacterial population over time, using rice plants as habitat to survive endophyticly until formation of bacterial panicle blight symptoms.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.1
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• pp.59-67
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• 1992

The duration of raising seedling of infant rice seedling(IRS) in machine transplanting is 8 to 10 days. This experiment was conducted to investigate the minimum duration of IRS's raising seedling and its method by the combination of several treatments such as plant growth regulator, root-break-seat and temperature. The rice seeds of Hwaseongbyeo was soaked in the solution of metalaxyl for 24 hours at room temperature. Metalaxyl (25% wettable powder), a fungicide, was used in 1, 000 times dilution as a promting substance on the root-mat formation of IRS. The application of fungicide in the nursery soil for the controlling of damping-off and physiologyical seedling rot was omitted due to the metalaxyl seed-soaking treatment. Seeding rate was 220g per seed tray (30$\times$60$\times$3cm). To promote the root-mat formation of IRS, the sheets of polyethylene vinyl and absorptive paper were placed bottom the seed tray. The root-mat formation of IRS was promoted at higher temperature and longer duration of raising seedling. The metalaxyl-treated seeds markedly increased the root length and rooting activity of IRS as compared with the control, thus the root-mat formation was excellent. The absorptive paper with polyethylene vinyl as root-break-seat showed a better root-mat formation compared with control, polyethylene vinyl, alone. The minimum duration of raising seedling of IRS was 5 days after sowing based on the root-mat formation and seedling height under the condition of metalaxyl seed treatment, absorptive paper with polyethylene vinyl as a root-break-seat and the raising seedling temperature 30/2$0^{\circ}C$ (day /night).

• 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.