• Journal of Bio-Environment Control
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• v.12 no.4
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• pp.180-183
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• 2003

P. wasabiae was isolated from discolored seeds of wasabi(Wasabia japonical Mtsum.) and inoculated to fresh seeds, then the effect of fungicides on suppression of diseases were determined. Emergence rate of wasabi seeds where suppressed to 52.5% by the inoculation and it reached up to 92.7% by dipping treatment of inoculated seeds ito benomyl solution. The incidence rate of black leg disease and damping off were 32.0 and 22.0%, respectively, in control treatment that sown in the soil inoculated with P. wasabiae. But dipping treatment of inoculated seeds into benomyl solution resulted in 12.0% and 10.7% in incidence rate of those two diseases, respectively.

• The Plant Pathology Journal
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• v.19 no.3
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• pp.181-183
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• 2003

Corky root symptoms caused by Pyrenochaeta lycopersici were observed on the roots and stem base of tomato plants in Korea. Symptoms on infected plants typically appeared as stunting and generally lacking vigor, and infected plants die back from the foliage tips after fruits have set. Brown lesions appearing with bands around the roots were characteristic symptoms of the disease. The lesions become swollen and cracked along the length of the root with corky appearance. Based on cultural and morphological characteristics, the fungus from the diseased plants was identified as Pyrenochaeta lycopersici. Pycnidia were solitary, globose to subglobose, brown to black, darker around the neck region, and measured 173-215 $\mu\textrm{m}$ in diameter with septate setae up to 102-132$\times$6.5 $\mu\textrm{m}$. Conidia were hyaline, unicellular, and 4.2-4.7$\times$l.5-2.0 $\mu\textrm{m}$ long. Optimum temperature for mycelial growth of the p. lycopersici isolates ranged from $20^{\circ}C$ to $25^{\circ}C$. Fifteen isolates off lycopersici were tested for pathogenicity to susceptible and tolerant cultivars of tomato plants by artificial inoculation. Three isolates of P. lycopersici induced typical corky root discoloration on susceptible tomato cultivars but not on tolerant tomato. This is the Erst report in Korea of tomato corky root disease caused by P. lycopersici.

• Journal of Ginseng Research
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• v.42 no.3
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• pp.304-311
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• 2018

Background: Ginseng black spot disease resulting from Alternaria panax Whuetz is a common soil-borne disease, with an annual incidence rate higher than 20-30%. In this study, the bacterial strains with good antagonistic effect against A. panax are screened. Methods: A total of 285 bacterial strains isolated from ginseng rhizosphere soils were screened using the Kirby-Bauer disk diffusion method and the Oxford cup plate assay. We analyzed the antifungal spectrum of SZ-22 by confronting incubation. To evaluate the efficacy of biocontrol against ginseng black spot and for growth promotion by SZ-22, we performed pot experiments in a plastic greenhouse. Taxonomic position of SZ-22 was identified using morphology, physiological, and biochemical characteristics, 16S ribosomal DNA, and gyrB sequences. Results: SZ-22 (which was identified as Brevundimonas terrae) showed the strongest inhibition rate against A. panax, which showed 83.70% inhibition, and it also provided broad-spectrum antifungal effects. The inhibition efficacies of the SZ-22 bacterial suspension against ginseng black spot reached 82.47% inhibition, which is significantly higher than that of the 25% suspension concentrate azoxystrobin fungicide treatment (p < 0.05). Moreover, the SZ-22 bacterial suspension also caused ginseng plant growth promotion as well as root enhancement. Conclusion: Although the results of the outdoor pot-culture method were influenced by the pathogen inoculum density, the cropping history of the field site, and the weather conditions, B. terrae SZ-22 controlled ginseng black spot and promoted ginseng growth successfully. This study provides resource for the biocontrol of ginseng black spot.

• The Korean Journal of Mycology
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• v.44 no.3
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• pp.193-195
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• 2016

Korean ginseng (Panax ginseng) possesses various biological and pharmacological properties. Damping-off is a critical disease on ginseng seedlings, which is caused by the fungal pathogens Rhizoctonia solani and Pythium sp.. This disease is generally controlled by the application of fungicides, but also biological control is an efficient and environmentally friendly way to prevent ginseng damping-off. In a previous study, we screened soil-borne bacteria with potential applications as biological control agents for ginseng damping-off and selected the bacterial strain Streptomyces sp. A3265, producing antifungal substances guanidylfungin and methylguanidylfungin. In this study, we investigated control efficacy of Streptomyces sp. A3265 against ginseng damping-off in the field. As a result, the incidence of damping-off was significantly reduced when soaking ginseng seeds in the culture broth of Streptomyces sp. A3265.

• The Plant Pathology Journal
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• v.37 no.4
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• pp.315-328
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• 2021

Fusarium and Rhizoctonia genera are important pathogens of many field crops worldwide. They are constantly evolving and expanding their host range. Selecting resistant cultivars is an effective strategy to break their infection cycles. To this end, we screened a collection of Medicago truncatula accessions against Fusarium oxysporum, Fusarium solani, and Rhizoctonia solani strains isolated from different plant species. Despite the small collection, a biodiversity in the disease response of M. truncatula accessions ranging from resistant phenotypes to highly susceptible ones was observed. A17 showed relative resistance to all fungal strains with the lowest disease incidence and ratings while TN1.11 was among the susceptible accessions. As an initiation of the characterization of resistance mechanisms, the antioxidant enzymes' activities, at the early stages of infections, were compared between these contrasting accessions. Our results showed an increment of the antioxidant activities within A17 plants in leaves and roots. We also analyzed the responses of a population of recombinant inbred lines derived from the crossing of A17 and TN1.11 to the infection with the same fungal strains. The broad-sense heritability of measured traits ranged from 0.87 to 0.95, from 0.72 to 0.96, and from 0.14 to 0.85 under control, F. oxysporum, and R. solani conditions, respectively. This high estimated heritability underlines the importance of further molecular analysis of the observed resistance to identify selection markers that could be incorporated into a breeding program and thus improving soil-borne pathogens resistance in crops.

• Korean Journal of Agricultural Science
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• v.49 no.1
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• pp.121-128
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• 2022

Fusarium wilt disease caused by Fusarium species is a major problem affecting cultivated cucurbit plants worldwide. Fusarium species are well-known soil-borne pathogenic fungi that cause Fusarium wilt disease in several cucurbit plants. In this study, we aimed to identify and classify pathogenic Fusarium species from cultivated Korean cucurbit plants, specifically watermelon and cucumber. Thirty-six Fusarium isolates from different regions of Korea were obtained from the National Institute of Horticulture and Herbal Science Germplasm collection. Each isolate was morphologically and molecularly identified using an internal transcribed spacer of ribosomal DNA, elongation factor-1α, and the beta-tubulin gene marker sequence. Fusarium species that infect the cucurbit plant family could be divided into three groups: Fusarium oxysporum (F. oxysporum), Fusarium solani (F. solani), and Fusarium equiseti (F. equieti). Among the 36 isolates examined, six were non-pathogenic (F. equiseti: 15-127, F. oxysporum: 14-129, 17-557, 17-559, 18-369, F. solani: 12-155), whereas 30 isolates were pathogenic. Five of the F. solani isolates (11-117, 14-130, 17-554, 17-555, 17-556) were found to be highly pathogenic to both watermelon and cucumber plants, posing a great threat to cucurbit production in Korea. The identification of several isolates of F. equiseti and F. oxysporum, which are both highly pathogenic to bottle gourd, may indicate waning resistance to Fusarium species infection.

• Research in Plant Disease
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• v.15 no.1
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• pp.30-35
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• 2009

This study was carried out to determine the causal agents of soil-borne fungal diseases that pose a threat to the muskmelon production in Cheong Yang, Korea and to investigate the potential effects of hot water drenching and three fumigant (metam sodium, dazomet and methyl bromide) on these diseases. As the agents of the diseases, Monosporascus cannonballus, Didymella sp., Fusarium sp., Phytophthora sp., were detected. Hot water and the fumigants were treated on two successive cropping seasons of melon. Soil temperature was measured at 0, 10, 20 and 30 cm soil depth. In 2005, soil sterilization by hot-water was more effective significantly to control of the diseases than by fumigant. yield was the highest in hot-water sterilized plot as $39\;ton{\cdot}ha^{-1}$. Dazomet ($50\;g/m^2$) treated plot was followed as $23\;ton{\cdot}ha^{-1}$. In 2006, hot water sterilized plot showed higher yields than non-treated plots ($14.8\;ton{\cdot}ha^{-1}$). But the other three fumigant contained Dazomet ($50\;g/m^2$) were no difference (P<0.05) in yield.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1997.11a
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• pp.3-31
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• 1997

Water has always played a significant role in the lives of people. In urbanised Rome, with its million people. sophisticated supply systems developed and then fled with the empire. only to be rediscovered later But it was the industrial Revolution commencing in the eighteenth century that ushered in major paradigm shifts In use and altitudes towards water. Rapid and concentrated urbanisation brought problems of expanded demands for drinking supplies, waste management and disease. The strategy of using water from local streams, springs and village wells collapsed under the onslaughts of rising urban demands and pollution due to poor waste disposal practices. Expanding travel (railways. and steamships) aided the spread of disease. In England. public health crises peaks, related to water-borne typhoid and the three major cholera outbreaks occurred in the late eighteenth and early nineteenth century respectively. Technological, engineering and institutional responses were successful in solving the public health problem. it is generally accepted that the putting of water into pipe networks both for a clean drinking supply, as well as using it as a transport medium for removal of human and other wastes, played a significant role in towering death rates due to waterborne diseases such as cholera and typhoid towards the end of the nineteenth century. Today, similar principles apply. A recent World Bank report Indicates that there can be upto 76％ reduction in illness when major water and sanitation improvements occur in developing countries. Water management, technology and thinking in Australia were relatively stable in the twentieth century up to the mid to late 1970s. Groundwater sources were investigated and developed for towns and agriculture. Dams were built, and pipe networks extended both for supply and waste water management. The management paradigms in Australia were essentially extensions of European strategies with the minor adaptions due to climate and hydrogeology. During the 1970s and 1980s in Australia, it was realised increasingly that a knowledge of groundwater and hydrogeological processes were critical to pollution prevention, the development of sound waste management and the problems of salinity. Many millions of dollars have been both saved and generated as a consequence. This is especially in relation to domestic waste management and the disposal of aluminium refinery waste in New South Wales. Major institutional changes in public sector water management are occurring in Australia. Upheveals and change have now reached ail states in Australia with various approaches being followed. Market thinking, corporatisation, privatisation, internationalisation, downsizing and environmental pressures are all playing their role in this paradigm shift. One casualty of this turmoil is the progressive erosion of the public sector skillbase and this may become a serious issue should a public health crisis occur such as a water borne disease. Such crises have arisen over recent times. A complete rethink of the urban water cycle is going on right now in Australia both at the State and Federal level. We are on the threshold of significant change in how we use and manage water, both as a supply and a waste transporter in Urban environments especially. Substantial replacement of the pipe system will be needed in 25 to 30 years time and this will cost billions of dollars. The competition for water between imgation needs and environmental requirements in Australia and overseas will continue to be an issue in rural areas. This will be especially heightened by the rising demand for irrigation produced food as the world's population grows. Rapid urbanisation and industrialisation in the emerging S.E Asian countries are currently producing considerable demands for water management skills and Infrastructure development. This trend e expected to grow. There are also severe water shortages in the Middle East to such an extent that wars may be fought over water issues. Environmental public health crises and shortages will help drive the trends.

• Korean journal of applied entomology
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• v.26 no.4 s.73
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• pp.229-237
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• 1987

In order to study the biological control of soil-borne disease of sesame, antagonistic isolates of Trichoderma , Bacillus sand streptomyces to Fusarium oxysporum and Rhizoctonia solani were isolated from the rhizosphere soils of sesame plants and some other habitats. Out of the isolates of microorganisms collected a strain of Trichoderma viride was selected as a biological control agent for the study and its effect on the control of damping-off and the seedling growth of sesame was investigated. The results obtained are as follows: 26 percents of Bacillus spp. isolated from the rhizosphere soil of sesame plants showed antagonism to two pathogenic fungi. Important species were B. Subtilis and B. polymyxa. Streptomyces species isolated from the rhizosphere soils of sesame lysed the cell wall of hyphae and conidia of F. oxysporum and reduced conspicuously the formation of macroconidia and chlamydospores of the fungus. 84 percents of Trichoderma spp. isolated from the rhizosphere soil of sesame plants were antagonistic to F. oxysporum and 60 percents of the isolates were antagonistic to both F. oxysporum and R. solani. Trichoderma viride TV-192 selected from antagonistic isolates of Trichoderma spp. was highly antagonistic to F. oxysporum and soil treatment with the isolate reduced notably damping-off of sesame. T. viride TV-192 showed better growth in crushed rice straw, barley straw and sawdust media than F. oxysporum. Sawdust was selective for the growth of T. viride. Supplementation of wheat bran and mixtures of wheat bran and sawdust inoculated with T. viride TV-192 in the soil reduced remarkably damping-off of sesame by F. oxysporum but high density of the fungus TV-192 caused the inhibition of seed germination and seedling growth of sesame. Inhibitory effects of Trichoderma species on seed germination and seedling growth of sesame were different according to the isolates of the fungus. Normal sesame seedlings on the bed treated with the fungus showed better growth than not treated seedlings.

• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.1
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• pp.1-11
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• 2015

In this study, an online seed potato sorting system using a visible and near infrared (40 1100 nm) transmittance spectral technique and statistical model was evaluated for the nondestructive determination of infected and sound seed potatoes. Seed potatoes that had been artificially infected with Pectobacterium atrosepticum, which is known to cause a soil borne disease infection, were prepared for the experiments. After acquiring transmittance spectra from sound and infected seed potatoes, a determination algorithm for detecting infected seed potatoes was developed using the partial least square discriminant analysis method. The coefficient of determination($R^2_p$) of the prediction model was 0.943, and the classification accuracy was above 99% (n = 80) for discriminating diseased seed potatoes from sound ones. This online sorting system has good potential for developing a technique to detect agricultural products that are infected and contaminated by pathogens.