• Journal of Microbiology and Biotechnology
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• v.19 no.5
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• pp.520-524
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• 2009

Two isolates, Bacillus sp. BS87 and RK1, selected from soil in strawberry fields in Korea, showed high levels of antagonism towards Fusarium oxysporum f. sp. fragariae in vitro. The isolates were identified as B. velezensis based on the homology of their gyrA sequences to reference strains. BS87 and RK1 were evaluated for control of Fusarium wilt in strawberries in pot trials and field trials conducted in Nonsan, Korea. In the pot trials, the optimum applied concentration of BS87 and RK1 for pre-plant root-dip application to control Fusarium wilt was $10^5$ and $10^6$ colony-forming units (CFU)/ml, respectively. Meanwhile, in the 2003 and 2005 field trials, the biological control efficacies of formulations of RK1 were similar to that of a conventional fungicide (copper hydroxide) when compared with a non-treated control. The RK1 formulation was also more effective than BS87 in suppressing Fusarium wilt under field conditions. Therefore, the results indicated that formulations of B. velezensis BS87 and RK1 may have potential to control Fusarium wilt in strawberries.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.802-811
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• 1996

Farmers need alternatives for weed control due to the desire to reduce chemicals used in farming. However, conventional mechanical cultivation cannot selectively remove weeds located in the seedline between crop plants and there are no selective heribicides for some crop/weed situations. Since hand labor is costly , an automated weed control system could be feasible. A robotic weed control system can also reduce or eliminate the need for chemicals. Currently no such system exists for removing weeds located in the seedline between crop plants. The goal of this project is to build a real-time , machine vision weed control system that can detect crop and weed locations. remove weeds and thin crop plants. In order to accomplish this objective , a real-time robotic system was developed to identify and locate outdoor plants using machine vision technology, pattern recognition techniques, knowledge-based decision theory, and robotics. The prototype weed control system is composed f a real-time computer vision system, a uniform illumination device, and a precision chemical application system. The prototype system is mounted on the UC Davis Robotic Cultivator , which finds the center of the seedline of crop plants. Field tests showed that the robotic spraying system correctly targeted simulated weeds (metal coins of 2.54 cm diameter) with an average error of 0.78 cm and the standard deviation of 0.62cm.

• Journal of Microbiology and Biotechnology
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• v.31 no.2
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• pp.250-258
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• 2021

Among various species of marine bacteria, those belonging to the genus Halomonas have several promising applications and have been studied well. However, not much information has been available on their antibiotic resistance. In our efforts to learn about the antibiotic resistance of strain Halomonas socia CKY01, which showed production of various hydrolases and growth promotion by osmolytes in previous study, we found that it exhibited resistance to multiple antibiotics including kanamycin, ampicillin, oxacillin, carbenicillin, gentamicin, apramycin, tetracycline, and spectinomycin. However, the H. socia CKY01 resistance pattern to kanamycin, gentamicin, apramycin, tetracycline, and spectinomycin differed in the presence of 10% NaCl and 1% NaCl in the culture medium. To determine the mechanism underlying this NaCl concentration-dependent antibiotic resistance, we compared four aminoglycoside resistance genes under different salt conditions while also performing time-dependent reverse transcription PCR. We found that the aph2 gene encoding aminoglycoside phosphotransferase showed increased expression under the 10% rather than 1% NaCl conditions. When these genes were overexpressed in an Escherichia coli strain, pETDuet-1::aph2 showed a smaller inhibition zone in the presence of kanamycin, gentamicin, and apramycin than the respective control, suggesting aph2 was involved in aminoglycoside resistance. Our results demonstrated a more direct link between NaCl and aminoglycoside resistance exhibited by the H. socia CKY01 strain.

• Korean journal of applied entomology
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• v.60 no.2
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• pp.203-214
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• 2021

This study aimed at establishing a packaging standardization method that allows the maintenance of biological control agents product quality during delivery. First, based on the results of distribution status analysis of biological control agent products from four manufacturers, we confirmed that the mean temperature was maintained at 25.6℃ (minimum and maximum temperatures.: 18.1 and 30.7℃, respectively) inside the packaging box of each company for 36-48 h. To establish the optimal packaging method for each season, seven external temperature conditions were set ranging between 0℃ and 30℃ at intervals of 5℃. In addition, we evaluated internal temperature maintenance performance for each coolant pack handling method and determined 14 packaging combinations. A packaging combination that maintained a temperature of 3℃ - 9.9℃ at each external temperature conditions was considered efficient. This temperature range is close to a lower developmental threshold at which the biological control agents can survive with minimum energy for 12 h (direct delivery time), or 36-48 h (general delivery time) after packaging.

• 한국균학회소식:학술대회논문집
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• 2016.05a
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• pp.25-25
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• 2016

Biological control has many advantages as a disease control method, particularly when compared with pesticides. One of the most important benefits is that biological control is an environmental friendly method and does not introduce pollutants into the environment. Another great advantage of this method is its selectivity. Selectivity is the important factor regarding the balance of agricultural ecosystems because a great damage to non target species can lead to the restriction of natural enemies' populations. The objective of this research was to evaluate the effects of several different bacterial isolates on the efficacy of biological control of soil borne diseases. White rot caused by Sclerotium cepivorum was reported to be severe disease of garlic and chive. The antifungal bacteria Burkholderia pyrrocinia CAB08106-4 was tested in field bioassays for its ability to suppress white rot disease. In field tests, B. pyrrocinia CAB08106-4 isolates suppressed white rot in garlic and chive, with the average control efficacies of 69.6% and 58.9%, respectively. In addition, when a culture filtrate of B. pyrrocinia CAB08106-4 was sprayed onto wounded garlic bulbs after inoculation with a Penicillium hirstum spore suspension in a cold storage room ($-2^{\circ}C$), blue mold disease on garlic bulbs was suppressed, with a control efficacy of 79.2%. These results suggested that B. pyrrocinia CAB08106-4 isolates could be used as effective biological control agents against both soil-borne and post-harvest diseases of Liliaceae. Chinese cabbage clubroot caused by Plasmodiophora brassicae was found to be highly virulent in Chinese cabbage, turnips, and cabbage. In this study, the endophytic bacterium Flavobacterium hercynium EPB-C313, which was isolated from Chinese cabbage tissues, was investigated for its antimicrobial activity by inactivating resting spores and its control effects on clubroot disease using bioassays. The bacterial cells, culture solutions, and culture filtrates of F. hercynium EPB-C313 inactivated the resting spores of P. brassicae, with the control efficacies of 90.4%, 36.8%, and 26.0%, respectively. Complex treatments greatly enhanced the control efficacy by 63.7% in a field of 50% diseased plants by incorporating pellets containing organic matter and F. hercynium EPB-C313 in soil, drenching seedlings with a culture solution of F. hercynium EPB-C313, and drenching soil for 10 days after planting. Soft rot caused by Pectobacterium carotovorum subsp. carotovorum was reported to be severe disease to Chinese cabbage in spring seasons. The antifungal bacterium, Bacillus sp. CAB12243-2 suppresses the soft rot disease on Chinese cabbage with 73.0% control efficacy in greenhouse assay. This isolate will increase the utilization of rhizobacteria species as biocontrol agents against soft rot disease of vegetable crops. Sclerotinia rot caused by Sclerotinia sclerotiorum has been reported on lettuce during winter. An antifungal isolate of Pseudomonas corrugata CAB07024-3 was tested in field bioassays for its ability to suppress scleritinia rot. This antagonistic microorganism showed four-year average effects of 63.1% of the control in the same field. Furthermore, P. corrugata CAB07024-3 has a wide antifungal spectrum against plant pathogens, including Sclerotinia sclerotiorum, Sclerotium cepivorum, Botrytis cinerea, Colletotrichum gloeosporioides, Phytophotra capsici, and Pythium myriotylum.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2005.04a
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• pp.65.2-66
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• 2005

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2005.04a
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• pp.68.2-68.2
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• 2005

• Proceedings of the Zoological Society Korea Conference
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• 2003.08a
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• pp.191.4-191
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• 2003

No Abstract, See Full Text

• Journal of Korean Society on Water Environment
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• v.21 no.4
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• pp.410-415
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• 2005

The main purpose of this study is to evaluate the characteristics of three sets of traditional control methods (proportional, integral, and proportional - integral controls) through lab-scale biological reactor experiments. An increase in proportional gain ($K_c$) resulted in reduced dissolved oxygen (DO) offset under proportional control. An increase in integral time ($T_i$) resulted in a slower response in DO concentration with less oscillation, but took longer to get to the set point. P-I control showed more stable and efficient control of DO and airflow rates compared to either proportional control or integral control. Developed P-I control system was successfully applied to lab-scale Sequencing Batch Reactor (SBR) for treating industrial wastewater with high organic strength.

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