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

• Research in Plant Disease
• /
• v.20 no.2
• /
• pp.87-94
• /
• 2014

The fungus Cylindrocarpon destructans is the cause of root rot in many ginseng production areas in Korea. A total of 57 isolates of C. destructans were recovered from diseased roots in a survey of ginseng-growing fields from 2011-2012. Among these isolates, 37% were classified as highly virulent (causing lesions on unwounded mature roots) and 61% were weakly virulent(causing lesions only on previously wounded roots). Radial growth of highly and weakly virulent isolates on potato dextrose agar was highest at $20^{\circ}C$ and there was no growth at $35^{\circ}C$. Mycelial mass production was significantly (P = 0.05) lower at pH 7.0 compared with pH 5.0. To study the effects of pH (5.0 and 7.0) and wounding on disease development, ginseng roots were grown hydroponically in nutrient solution. Lesions were significantly larger (P < 0.01) at pH 5.0 compared with pH 7.0 and wounding enhanced disease by a highly virulent isolate at both pHs. In artificially infested soil, 2-yearold ginseng roots were most susceptible to Cylindrocarpon root rot among all root ages tested (1 to 4 years) when evaluated using a combined scale of disease incidence and severity. Root rot severity was significantly (P<0.05) enhanced by increasing the inoculum density from $3.5{\times}10^2cfu/g$ of soil to $2.0{\times}10^3cfu/g$ of soil.

• The Plant Pathology Journal
• /
• v.30 no.4
• /
• pp.432-436
• /
• 2014

The soil-borne ascomycete fungus Cylindrocarpon destructans causes ginseng root rot disease and produces various secondary metabolites such as brefeldin A and radicicol. The slow growth of this fungus compared with other plant pathogenic and saprophytic fungi in soil disturbs isolation of this fungus from soil and infected ginseng. In this study, we developed a selective medium for C. destructans using radicicol produced by this fungus. Supplementing 50 mg/L of radicicol to medium inhibited the mycelia growth of other fungi including Botrytis cinerea, Rhizoctonia solani and Alternaria panax, but did not affect the growth of C. destructans. In addition, conidia germination of other fungal species except for C. destructans was inhibited in submerged culture supplemented with radicicol. This medium provides a very efficient tool for isolating C. destructans and also can be used as an enrichment medium for this fungus.

• Journal of Microbiology and Biotechnology
• /
• v.30 no.7
• /
• pp.1018-1026
• /
• 2020

Rosemary essential oil was evaluated for antifungal potentiality against six major ginseng pathogens: Sclerotinia sclerotiorum, Sclerotinia nivalis, Cylindrocarpon destructans, Alternaria panax, Botrytis cinerea, and Fusarium oxysporum. The in vitro fungicidal effects of two commonly used fungicides, namely mancozeb and fenhexamid, and the volatile organic compounds (VOCs) of Trichoderma koningiopsis T-403 on the mycelial growth were investigated. The results showed that rosemary essential oil is active against all of the pathogenic strains of ginseng root rot, whereas rosemary oil displayed high ability to inhibit the Sclerotinia spp. growth. The highest sensitivity was S. nivalis, with complete inhibition of growth at 0.1% v/v of rosemary oil, followed by Alternaria panax, which exhibited 100% inhibition at 0.3% v/v of the oil. Minimum inhibitory concentrations (MICs) of rosemary oil ranged from 0.1 % to 0.5 % (v/v). Chemical analysis using GC-MS showed the presence of thirty-two constituents within rosemary oil from R. officinals L. Camphore type is the most frequent sesquiterpene in rosemary oil composition. Mancozeb and fenhexamid showed their highest inhibition effect (45% and 30%, respectively) against A. panax. T. koningiopsis T-403 showed its highest inhibition effect (84%) against C. destructans isolate. This study may expedite the application of antifungal natural substances from rosemary and Trichoderma in the prevention and control of phytopathogenic strains in ginseng root infections.

• Korean Journal of Soil Science and Fertilizer
• /
• v.49 no.2
• /
• pp.138-143
• /
• 2016

The objective of this study was to evaluate the effects of the application of vermicomposts on the growth parameters and ginsenoside content of ginseng roots. Food waste vermicompost (FW), cow manure vermicompost (CM), and paper sludge vermicompost (PS) were applied at 10 and $40t\;ha^{-1}$, respectively. One-year-old seedlings were transplanted and 4-year-old roots were harvested. Soil nitrate and phosphate concentrations were increased in the plots applied with FW and CM at $40t\;ha^{-1}$. Soil pH and exchangeable Ca concentrations were higher at FW $40t\;ha^{-1}$ than at CM $40t\;ha^{-1}$. Root yield increased when treated with FW $40t\;ha^{-1}$ in comparison to the yield for the control. The incidences of root rot disease and ginsenoside content were not significantly affected by the treatments. The results suggested that application of vermicompost might not show a relationship between root biomass and ginsenoside content. It further showed that proper use of vermicompost can promote root yield without a reduction in root quality or an increase in the incidence of root rot disease in reclaimed fields.

• Korean Journal of Medicinal Crop Science
• /
• v.24 no.2
• /
• pp.136-142
• /
• 2016

Background: Root diseases caused by Cylindrocarpon destructans and Fusarium solani decrease the yield and quality of ginseng. Cylindrocarpon root rot is a major disease caused by replant failure in ginseng fields. Methods and Results: Solarization of infested greenhouse soil was carried out during the summer season after applying green manure (Sudan grass) and Calcium Cyanamide (CC) on the soil. Mycelium and conidia of C. destructans died at $40^{\circ}C$ after 15 h, but they did not die at $35^{\circ}C$ after 15 h. They also died after keeping the soil at $40^{\circ}C$ for 2 h daily for 9 days, and at $45^{\circ}C$ for 8 days, but they did not die at $38^{\circ}C$ for 9 days. Maximum soil temperature was $55.4^{\circ}C$ at 5 cm depth, $48.7^{\circ}C$ at 10 cm, $44.7^{\circ}C$ at 15 cm, $42.5^{\circ}C$ at 20 cm, and $31.9^{\circ}C$ at 30 cm by incorporating green manure into the soil and using solarization. Solarization using green manure mixed with CC was the most effective in decreasing soil-borne pathogens of 2-year-old ginseng. However, the addition of CC decreased the root weight due to the increase in EC and $NO_3-N$. Conclusions: Soil disinfection using green manure and solarization in a greenhouse environment was effective in inhibiting root rot, however, it did not completely kill the soil-borne pathogens.

• Korean Journal of Pharmacognosy
• /
• v.3 no.2
• /
• pp.73-79
• /
• 1972

Losses, literature and occurence of ginseng diseases in Korea were reviewed briefly. Some problems on etiology, epidemiology and control measures of root rot caused by Cylindroaroon panacis, anthracnose, and damping-off have been discussed. Ginseng was added as a new host of $Sclerotium\;rolfsii\;S_{ACC}$.

• Journal of Ginseng Research
• /
• v.40 no.1
• /
• pp.38-46
• /
• 2016

Background: Blind and excessive application of fertilizers was found during the cultivation of Panax notoginseng in fields, as well as increase in root rot disease incidence. Methods: Both "3414" application and orthogonal test designs were performed at Shilin county, Yunnan province, China, for NPK (nitrogen, phosphorus, and potassium) and mineral fertilizers, respectively. The data were used to construct the one-, two-, and three-factor quadratic regression models. The effect of fertilizer deficiency on root yield loss was also analyzed to confirm the result predicted by these models. A pot culture experiment was performed to observe the incidence rate of root rot disease and to obtain the best range in which the highest yield of root and saponins could be realized. Results: The best application strategy for NPK fertilizer was $0kg/667m^2$, $17.01kg/667m^2$, and $56.87kg/667m^2$, respectively, which can produce the highest root yield of 1,861.90 g (dried root of 100 plants). For mineral fertilizers, calcium and magnesium fertilizers had a significant and positive effect on root yield and the content of four active saponins, respectively. The severity of root rot disease increased with the increase in soil moisture. The best range of soil moisture varied from 0.56 FC (field capacity of water) to 0.59 FC, when the highest yield of root and saponins could be realized as well as the lower incidence rate of root disease. Conclusion: These results indicate that the amount of nitrogen fertilizer used in these fields is excessive and that of potassium fertilizer is deficient. Higher soil moisture is an important factor that increases the severity of the root rot disease.

• Journal of Ginseng Research
• /
• v.27 no.4
• /
• pp.195-201
• /
• 2003

Chlamydospore formation from mycelia and conidia of Cylindrocarpon destructans isolated from the root rot lesion of the Panax ginseng was investigated by scanning electron and light microscopy. Typical chlamydospores were formed only from hyphae but not from conidia on culture media. However, immature chlamydopspore-like cells were formed from microconidia after 12 days of incubation at 20$^{\circ}C$ on Czapek Dox broth (CDB) adjusted to pH 4.0. Chlamydospores were yellowish or reddish brown in color, and produced singly or in chain with the hyphal intercalary or terminal position on potato-dextrose agar, V-8 juice agar and CDB with no addition of nitrogen sources after 16∼20 days of incubation at 20$^{\circ}C$. They were 11.3 to 11.9 $\mu\textrm{m}$ in diameter, having many lumps-like warts on their surface with the length of 1.5 to 1.8 $\mu\textrm{m}$.

• Journal of Ginseng Research
• /
• v.22 no.4
• /
• pp.304-309
• /
• 1998

Incubation condition affecting the chlamydospore formation and isolation from mycelia and conidia of Cylindrocarpon destructanse (isolate ACY-9701), isolated from the root rot lesion of the American ginseng (Panax quinquefolium) was investigated. Chlamydospores were formed from mycilia but not from conidia on the Czapek-Dox agar without carbon or nitrogen source after 20 days incubation at 2$0^{\circ}C$. In the medium added with nitrogen and carbon sources, immatured chlamy-dospore-like cells were formed from microconidia and mycelia as well. Immatured chlamydospore-like cells were formed from mycelia as well as microconidia In corn, kidney bean, and pea root extracts after 20 days incubation at 20"C, while typical chlamydospores were formed from both of them in the root extract of Panax quinquefolium. The 3.6 log chlamydospore/mm" was converted from microconidia in the medium, which was equal to 2.5% conidia formed. Under the light condition (251.1 pmol/m" sec, 12 hrs dark and light cycle), 4.2 log/mm" of chlamydospores were converted from interracially or terminal cells of macroconidia, which was 4.0% of macroconidia produced on Potato dextrose agar (PDA). When mycelia and microconidia were stored at -7$0^{\circ}C$ for 32 days and incubated on PDA after thawing at room temperature to isolate chlamydospores from them, microconidia and mycelia were still alive. Meanwhile, microconidial lysis was found after heating them at 32$^{\circ}C$ for 7 days, but the chlamydospores converted from macroconidia were not lysed up to 13 days at 32"C. to 13 days at 32"C.ot;C.