• The Plant Pathology Journal
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• v.35 no.5
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• pp.406-416
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• 2019

Strawberry, an important fruit crop, is susceptible to a large number of pathogens that reduce fruit quality and productivity. In this study, the effect of a biostimulant prepared from Ascophyllum nodosum extract (ANE) (0.1%, 0.2%, and 0.3%) was evaluated on powdery mildew progression under greenhouse and field conditions. In the greenhouse, application of 0.2% ANE showed maximum reduction in powdery mildew progression as compared to the control. Forty-eight hour post-inoculation, foliar spray of 0.2% ANE reduced spore germination by 75%. Strawberry leaves sprayed with ANE showed higher total phenolic and flavonoid content in response to powdery mildew infection. Furthermore, application of ANE elicited defense response in strawberry plants by induction of defense-related enzymes, such as phenylalanine ammonia lyase, polyphenol oxidase, and peroxidase activity. In field conditions, foliar spray of 0.2% ANE showed a reduction of 37.2% of natural incidence of powdery mildew infection as compared to the control. ANE sprayed plant also reduces the severity of powdery mildew infection under natural conditions. These results indicate that application of ANE induces the strawberry plant's active defense against powdery mildew infection by induction of secondary metabolism and regulating the activities of defense-related enzymes.

• Mycobiology
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• v.49 no.1
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• pp.69-77
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• 2021

The application of antagonistic fungi for plant protection has attracted considerable interest because they may potentially replace the use of chemical pesticides. Antipathogenic activities confirmed in volatile organic compounds (VOCs) from microorganisms have potential to serve as biocontrol agents against pre- and post-harvest diseases. In the present study, we investigated Galactomyces fungi isolated from rotten leaves and the rhizosphere of cherry tomato (Lycopersicon esculentum var. cerasiforme). VOCs produced by Galactomyces fungi negatively affected the growth of phytopathogenic fungi and the survival of nematodes. Mycelial growths of all nine examined phytopathogenic fungi were inhibited on agar plate, although the inhibition was more intense in Athelia rolfsii JYC2163 and Cladosporium cladosporioides JYC2144 and relatively moderate in Fusarium sp. JYC2145. VOCs also efficiently suppressed the spore germination and mycelial growth of A. rolfsii JYC2163 on tomatoes. The soil nematode Caenorhabditis elegans exhibited higher mortality in 24 h in the presence of VOCs. These results suggest the broad-spectrum activity of Galactomyces fungi against various plant pathogens and the potential to use VOCs from Galactomyces as biocontrol agents.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.30-30
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• 2022

Natural products decursin and decursinol angelate were recently reported as benign fungicides for controlling rice blast. Inspired by the structural similarity of the cumarin compounds and gained hint from the skeletal motifs, we designed and prepared synthetic compounds to increase the natural product efficacy and evaluated their antifungal activities against various plant disease pathogens in vitro. Synthetically prepared compound 4 and 5 indeed suppressed the mycelial growth of B. cinerea, F. oxysporum, P. italicum, and R. quercus-mongolicae. Additionally, compound 5 effectively prevents the growth of C. coccodes and C. parasitica. Furthermore, both 4 and 5 possess better inhibitory activities on spore germination of F. oxysporum and M. oryzae than the natural product decursin. These results suggest that the effect of the lead compound for plant disease protection can be improved by tuning the structure of the original natural product and decursinol chloroacrylates 4 and 5 are candidates for the control of F. oxysporum and M. oryzae.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.98-98
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• 2022

Natural products decursin and decursinol angelate were recently reported as benign fungicides for controlling rice blast. Inspired by the structural similarity of the cumarin compounds and gained hint from the skeletal motifs, we designed and prepared synthetic compounds to increase the natural product efficacy and evaluated their antifungal activities against various plant disease pathogens in vitro. Synthetically prepared compound 4 and 5 indeed suppressed the mycelial growth of B. cinerea, F. oxysporum, P. italicum, and R. quercus-mongolicae. Additionally, compound 5 effectively prevents the growth of C. coccodes and C. parasitica. Furthermore, both 4 and 5 possess better inhibitory activities on spore germination of F. oxysporum and M. oryzae than the natural product decursin. These results suggest that the effect of the lead compound for plant disease protection can be improved by tuning the structure of the original natural product and decursinol chloroacrylates 4 and 5 are candidates for the control of F. oxysporum and M. oryzae.

• Research in Plant Disease
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• v.23 no.2
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• pp.159-167
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• 2017

This study was conducted to evaluate the control efficacy of the organic farming materials on cucumber scab caused by Cladosporium cucumerinum PT1 (KACC 48094). The antifungal activities in vitro as well as the suppressive effect of 43 organic farming materials on the spore germination and germ tube growth by inoculating spore suspension on cucumber seedlings in vivo were investigated. Thirteen organic farming materials inhibited the mycelial growth of C. cucumerinum and nine of these were microbial agents. In the screening using cucumber seedlings, six organic farming materials were very effective with control efficacy value of 90%. Among them, Bacillus amyloliquefaciens M27 provided suppressive effect on both mycelial growth and spore germination against cucumber scab. Finally, nine organic farming materials were selected to test the protective and curative effects, and all chosen organic farming materials significantly suppressed disease incidence when applied in the preventive action, in comparison with the curative action. Especially, Bordeaux mixture I and III gave excellent protective control efficacy with control values of 96.7% and 73.3%, respectively, whereas its curative control effect was significant low. Among these, only Thymus quinquecostatus+Sophora extract showed curative activity, although the control value was as low as 50%. This study suggests that cucumber scab can be controlled by some organic farming materials in the farmhouses under comparatively cold and wet condition and protective treatment is more important and efficient.

• Korean journal of applied entomology
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• v.21 no.1 s.50
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• pp.27-33
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• 1982

Thytealexin activities were investigated in compatible and incompatible combinations between rice cultivars and races of Pyricularia oryzae by using the spore-germination test in the diffusates from surface of leaf-blade treated with the spore suspensions. In compatible and incompatible combinations between nine cultivars of rice and three races of the fungus, phytoalexin activities were recognized in all combinations, and were much higher in incompatible combinations than in compatible combinations with significant differences. Activities of phytoalexin were increased with the time, and maximal peaks of them were at 36 hours after inoculation, and thereafter decreased. The activities were generally decreased in all combination by heavy applications of nitrogen fertilizer, especially in incompatible combinations. On the other hand, fresh juices from leaves of rice cultivars which were not inoculated with the fungus showed no phytoalexin activities.

• Korean Journal of Veterinary Service
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• v.18 no.1
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• pp.41-56
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• 1995

The present study was conducted to investigate results of B. anthracis isolated from Anthrax in the Kyong-Ju of Feb. 12. 1994. 1. In biochemical feature, B. anthracis was a gram-positive rod, non-motility, sporulation, capsulation. It was positive in gelatinase, starch hydrolysis, glucose. But negative in urease, arabinose, mannitol, xylose. 2. B. anthracis grew well on B4 Br A TSA after incubation for 24 hours. The organisim grew well on BA, Br. A, NA, TSA after incubation for 72 hours. The media grew well on Br A instead of BA. 3. On 5% blood agar by laboratory animal, ${\beta}$ -hemolysis was produced from 36 hours to 48 hours incubation. There was perfect ${\beta}$-hemolysis after incubation for 48 hours. On the other side ${\beta}$-hemolysis was begun on 5% goat blood agar after incubation for 60 hours. 4. In the test of antimicrobial susceptibility, B. anthracis was very sensitive to AM, CF, TE, ENR, GM, AN, DFX, S, P, TYLO, N, KM, C, E, Lins＋Sp, NN, CC, CFP, CB were sensitive one by one. B. anthracis was no-sensitive to L, XNL, TIA, CL, SXT 5. B. anthracis had never sensitivity to direct inoculation of rat and chicken, after subcutanous inj. It was very sensitive to mouse and goat, hamster, guinea pig, rabbit had a sensibility one by one. 6. The dead laboratory animal which had been inoculated with B. anthracis preserved at $37^{\circ}C$ incubation, B. anthracis didn't cultivate on non-dissected animal after 80 hours but cultivate on dissected animal after 360 hours. 7. The rapidly death could cause high concentration, died from 420 after S. C. 8. The blood smeared samples of hamster from inoculation with B. anthracis, spore germinated In 37$^{\circ}C$ after 5 hours, in $32^{\circ}C$ after 6 hours, in room temperature after 9 hours, in $-4^{\circ}C$ to $-20^{\circ}C$ after 10 hours. 9. B, anthracis inoculated to laboratory animal after SC or PO. Mice and rats feces didn't cultivated with B. anthracis after SC, but did cultivated with B. anthracis after PO. 10. In the test of disinfectant, B. anthracis was high effective to $HgC1_2$, formalin, effect phenol, cresol, but non-effect NaOH, ethanol.

• Korean Journal of Organic Agriculture
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• v.23 no.3
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• pp.567-582
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• 2015

Botrytis cinerea infects stems, leaves and fruits of greenhouse tomato and can cause serious economic losses. This study was conducted to develop organic farming control method against tomato gray mold. Twenty two organic farming materials including mineral and plant extracts were screened for the suppressive activity against Botrytis cinerea, in vitro and in vivo. Among the organic farming materials, sulfur, copper, Chinese twinleaf extract and rhubarb extract decreased by 51.7-90% of the spore germination of Botrytis cinerea. Also, gray mold incidence was reduced more than 90% on tomato stems by treating sulfur, seaweed extracts, rhubarb root extracts and Chinese twinleaf extract. After the selected four organic farming materials were applied on tomato cultivated in greenhouse, their control effects against the tomato gray mold were tested. When the water soluble sulfur was foliar-sprayed on the tomato leaves infected by artificial inoculation with spore suspension of Botrytis cinerea, it showed 87.9% of control value. Also, control activity of the water soluble sulfur was paralleled with chemical fungicide, diethofencarb+carbendazim. The above mentioned results indicate the sulfur formulation can be used as chemical fungicide alternatives for controlling tomato gray mold in the greenhouse.

• Research in Plant Disease
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• v.29 no.1
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• pp.11-22
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• 2023

Resazurin-based microtiter assay was used to evaluate the inhibitory effect of fungicides on the respiration of Colletotrichum acutatum s. lat. 20JDS8 sensitive and 20CDJ6 resistant to strobilurin fungicides. The spores of C. acutatum s. lat. 20JDS8 were inoculated into potato dextrose broth (PDB) at densities of 1x10⁴, 1x10⁵ and 1x10⁶ spores/ml, respectively. The relative fluorescence unit (RFU) of all treatments inoculated at each spore density started to rise after 12 hr of incubation, and were 1,965.5, 5,412.5, and 10,061.0, respectively, after 24 hr of incubation. To evaluate the inhibitory effect of fungicide on the respiration of the pathogen, the spores of the pathogen were inoculated into the PDB and treated with the fungicides 0, 6, 12, and 24 hr after incubation, respectively. After keeping the pathogen culturing for another 24 hr, PrestoBlue reagent was treated into the PDB culturing the pathogen. The RFU of each treatment was examined 1 hr after the reagent was treated. When dithianon, isopyrazam, pyraclostrobin, and fluazinam were treated at high concentrations in the stages of spores (immediately after inoculation [0 hr]), spore germination (after incubation for 6 hr), and hyphal growth (after incubation for 12 hr), the respiration of pathogens was inhibited by 90-100%. When the fungicides were treated after culturing the pathogen for 24 hr, the respiratory inhibitory effects were greatly reduced. With pyraclostrobin-resistant C. acutatum s. lat. 20CDJ6, azxoystrobin, trifloxystrobin and kresoxim-methyl, which have the same mode of action, had very little or no respiratory inhibitory effect in all growth stages of pathogens. Based on the above results, it was thought that the resazurin-based microtiter assay could quickly and accurately evaluate the inhibitory efficacy of the fungicides that inhibited respiration.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.4
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• pp.85-94
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• 2016

The purpose of this study was to characterize the coffee ground and its possibility to develop the antifungal activity. pH, EC, and Zn contents of the coffee ground from coffee shops were higher than those of commercial coffee ground, but there was no significant difference in $K_2O$, CaO, MgO, $Na_2O$, Mn contents. The antimicrobial activity of the water soluble extracts from the coffee shop and the commercial coffee ground were tested for six major plant pathogens, Rhizoctonia solani, Sclerotinia sclerotiorum, Fusarium oxysporum, Phytophthora capsici, Alternaria alternata, and Botrytis cinerea. The result showed that there was reliable antifungal activity against all of tested plant pathogenic fungi. The inhibition effects of coffee ground compost extract on the spore germination and zoospore formation were investigated. Water soluble extracts of the coffee ground compost mixture added with 10% sesame oil cake were significantly inhibited the growth of conidia germination of A. altanata and zoospore formation of P. capsici in vitro. For investigating the functional materials of coffee ground compost, it was measured the total polyphenolic compounds contents with 30 days interval during decomposing coffee ground for 90 days. The total polyphenolic content increased with decomposing periods, and it observed that the highest total polyphenolic content was $0.35{\pm}0.03mg\;GAE/g$ on the 90th day in the coffee ground compost added with 10% sesame oil cake.