• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2000.10a
• /
• pp.42.1-42
• /
• 2000

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 1994.06a
• /
• pp.62-74
• /
• 1994

The current status of the development of commercial products for the biological control of plant-parasitic nematodes is discussed. an example is given of problems encountered by our program in patenting biocontrol agents in the United Stats. Two hypothetical approaches to the control of plant nematodes are considered. First recent experimental results relating to the theory on intervention with host-finding by plant nematodes are reviewed. Second, a newer hypothesis considering the possibilities for genetic approaches to modifying molecular signals between nematodes and their parasites is described.

• Korean Journal Plant Pathology
• /
• v.11 no.4
• /
• pp.287-291
• /
• 1995

Biocontrol agents, Gliocladium virens G872B and Pseudomonas putida Pf3, were compatible each other in colonizing cucumber rhizosphere, which contributed to a long-term inhibition of cucumber Fusarium wilt. G872B colonized successfully on the cucumber root system, irrespective of the introduction of Pf3. Pf3 also colonized well in the cucumber rhizosphere regardless of the presence of G872B. The individual strains effectively suppressed cucumber wilt up to 56 days after transplanting. The combined treatment of G872fB and Pf3 provided a long-term protection of about 80 days with the efficacy greater than that obtained by any individual strains under greenhouse conditions. These results suggest that the colonization of the biological control agents in the rhizosphere could be correlated directly to Fusarium wilt-suppressive potentials.

• Microbiology and Biotechnology Letters
• /
• v.23 no.2
• /
• pp.243-248
• /
• 1995

Agrochemicals for the plant-disease control are criticized severely for causing environmental pollution and residual problems, and consequently microbial disease control agents are expected to be safer and more economical for sustainable agriculture. Treatment of biological control agents to seed requires the use of effective delivery systems that allow full expression of the benefical qualities of the bioprotectant. For the activation and establishment of bioprotectant around the plant seed which are able protect the seeds and seedlings from pathogen attack, the optimal liquid coating formulation was obtained using 2% sodium carboxymethyl cellulose (binder), 20% sesame dregs (solid particulate material), and dried spore of Bacillus subtilis YBL-7 (bioprotectants, 10 mg/g of seed). Suppressive of root rot was demonstrated in pot trials with coated kidney bean (Phaseolus vulgaris L.) seeds. Coated seeds with B. subtilis YBL-7 spore in F. solani-infested soil reduced disease incidence by 85% to 90% after 30 days.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2017.04a
• /
• pp.27-27
• /
• 2017

Biocompatible capsules have recently been highlighted as novel delivery platforms of any "materials" (e.g., drug, food, agriculture pesticide) to address current problems of living systems such as humans, animals, and plats in academia and industry for agriculture, biological, biomedical, environmental, food applications. For example, biocompatible alginate capsules were proposed as a delivery platform of biocontrol agents (e.g., bacterial antagonists) for an alternative to antibiotics, which will be a potential strategy in future agriculture. Here, we proposed a new platform based on biocompatible alginate capsules that can control the movements as an active target delivery strategy for various applications including agriculture and biological engineering. We designed and fabricated large scale biocompatible capsules using alginates and custom-made nozzles as well as gelling solutions. To develop the active target delivery platforms, we incorporated the iron oxide nanoparticles in the large scale alginate capsules. It was found that the sizes of large scale alginate capsules could be controlled via various working conditions such as concentrations of alginate solutions and iron oxide nanoparticles. As a proof of concept work, we showed that the iron oxide particles-incorporated large scale alginate capsules could be moved actively by the magnetic fields, which would be a strategy as active target delivery platforms for agriculture and biological engineering (e.g., controlled delivery of agriculture pesticides and biocontrol agents).

• Microbiology and Biotechnology Letters
• /
• v.36 no.1
• /
• pp.21-27
• /
• 2008

As an effort to search new bacterial biocontrol agents against pepper anthracnose, we screened myxobacteria, which might inhibit the growth of Colletotrichum acutatum, the agent of that plant disease. When 93 myxobacterial strains including 59 Myxococcus spp. and 34 Corallococcus spp. were tested against C. acutatum ACYSJ001 on agar plates, 10 strains identified as the genus Myxococcus significantly obstructed the growth of C. acutatum, whereas the majority of strains belonging to the genus Corallococcus did not demonstrate any counteractive effect. Such results have indicated that the strains of the genus Myxococcus have a high potential to play roles of biocontrol agents for control of pepper anthracnose. These also have revealed that the strains of the genus Myxococcus could be used as excellent microbial resources for screening novel antifungal substances.

• The Plant Pathology Journal
• /
• v.31 no.1
• /
• pp.50-60
• /
• 2015

The use of novel isolates of Trichoderma with efficient antagonistic capacity against Fusarium oxysporum f. sp. lycopersici (FOL) is a promising alternative strategy to pesticides for tomato wilt management. We evaluated the antagonistic activity of 30 isolates of T. asperellum against 4 different isolates of FOL. The production of extracellular cell wall degrading enzymes of the antagonistic isolates was also measured. The random amplified polymorphic DNA (RAPD) method was applied to assess the genetic variability among the T. asperellum isolates. All of the T. asperellum isolates significantly reduced the mycelial growth of FOL isolates but the amount of growth reduction varied significantly as well. There was a correlation between the antagonistic capacity of T. asperellum isolates towards FOL and their lytic enzyme production. Isolates showing high levels of chitinase and ${\beta}$-1,3-glucanase activities strongly inhibited the growth of FOL isolates. RAPD analysis showed a high level of genetic variation among T. asperellum isolates. The UPGMA dendrogram revealed that T. asperellum isolates could not be grouped by their antagonistic behavior or lytic enzymes production. Six isolates of T. asperellum were highly antagonistic towards FOL and potentially could be used in commercial agriculture to control tomato wilt. Our results are consistent with the conclusion that understanding the genetic variation within Trichoderma isolates and their biochemical capabilities are required for the selection of effective indigenous fungal strains for the use as biocontrol agents.

• Journal of Biosystems Engineering
• /
• v.42 no.4
• /
• pp.323-329
• /
• 2017

Purpose: Biocompatible capsules have recently been highlighted as a novel platform for delivering various components, such as drug, food, and agriculture pesticides, to overcome the current limitations of living systems, such as those in agriculture, biology, the environment, and foods. However, few active targeting systems using biocompatible capsules and physical forces simultaneously have been developed in the agricultural engineering field. Methods: Here, we developed an active targeting delivery platform that uses biocompatible alginate capsules and controls movements by magnetic forces for agricultural and biological engineering applications. We designed and fabricated large-scale biocompatible capsules, using custom-made nozzles ejecting alginate solutions for encapsulation. Results: To develop the active target delivery platforms, we incorporated iron oxide nanoparticles in the large-scale alginate capsules. The sizes of alginate capsules were controlled by regulating the working conditions, such as concentrations of alginate solutions and iron oxide nanoparticles. Conclusions: We confirmed that the iron oxide particle-incorporated large-scale alginate capsules moved actively in response to magnetic fields, which will be a good strategy for active targeted delivery platforms for agriculture and biological engineering applications, such as for the controlled delivery of agriculture pesticides and biocontrol agents.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 1994.06a
• /
• pp.27-49
• /
• 1994

Root colonization of biocontrol agents via seed treatment was investigated and a compatible combination, Gliocladium virens G872B and Pseudomonas putida Pf3, in colonizing cucumber rhizosphere was confirmed through the study. Much higher number of fungal and bacterial propagules were detected when two isolates were inoculated together. The presence of Pf3 in root system was greatly helpful to G872B to colonize at root tip. The mechanism of this phenomenon is partially elucidated through the results of in vitro experiments and the observations of scanning electron and fluorescence microscope. Addition of Pf3 cells resulted earlier germination of G872B conidia and increased mycelial growth. And the more number of germinated conidia on seed coat, the more vigorous hypal streching and sporulation on the root surface were observed in coinoculated treatment. The propagules of G872B on the cucumber root when they were challenged against the pathogenic Fusarium oxysporum, were even higher than that of G872B treated alone, and the magnitude of such a difference was getting grater toward the root ip and the population of F. oxysporum on the root was reduced by seed inoculation of G872B. The rhizosphere competence was obviously reflected to disease suppression and plant growth promotion that induced by the given isolate. Green house experiments revealed that the combined treatment provided long-term disease suppression with greater rate and the larger amount of fruit yield than single treatments. Through this study the low temperature growing Pseudomonas fluorescens M45 and MC07 were evaluated to apply them to the winter crops in field or plastic film house. In vitro tests reveal that M45 and MC07 inhibited the mycelial growth of Pythium ultimum, Rhizoctona solani and Phytophthora capsici and enhanced growth of cucumber cotyledon in MS agar. This effect was more pronounced when the bacteria were incubated at 14$^{\circ}C$ than at 27$^{\circ}C$. And disease suppression and plant growth promotion in green house were also superior at low temperature condition. Seed treatment of M45 or soil treatment of MC07 brought successful control of damping-off and enhanced seedling growth of cucumber. The combined treatment of two isolates was more effective than any single treatment.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.104.2-105
• /
• 2003

Bacterial isolates, CC178, PTC25, HC39 and KY165 originally obtained from the leaves of cucumber or tomato were selected for biocontrol agents against gray mold of cucumber and tomato by in vivo cucumber seedling assay. Each suspension of the selected epiphytic bacteria were sprayed three times at seven-day interval from early stage of cucumber in a field. Incidence of gray mold on cucumber fruits treated with isolates CC178, PTC25, HC39 and KY165 was 15.3％, 18.2％, 23.6％, and 10.4％, respectively, whereas that of control was 38.0％ after 7 days of final spray. On the other hand, treatment with the selected isolates, CC178, PTC25, HC39, and KY165 on tomato showed 2.2％, 1.3％, 2.9％, and 3.5％ in the incidence of gray mold on leaves, whereas that of control was 9.3％. All selected isolates had strong antagonistic activity against Botrytis cinerea on dual culture plate assay.