• 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.

• The Korean Journal of Mycology
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• v.26 no.3 s.86
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• pp.407-410
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• 1998

The aphid-attacking fungus Pandora neoaphidis was collected during May and June, 1998 at various localities: two localities at Kyunggi, three at Kangwon, one at Kyungbuk and one at Chungnam Provinces. Occurrence of this fungus has never been recorded in Korea. The potential host aphids are Acyrthosiphon kondoi, Myzus persicae, Lipaphis erysimi, Sitobion avenae, Aphis rumicis, Dactynotus species and unknown species. Microscopic characters of the fungus are described and illustrated. Pandora neoaphidis studied in this study has an extremely broad range in conidial size and shape even within a single specimen. Such variable size and shape are typical characters of the fungus. During microscopic examination of specimens, the resting-spore phase was not observed.

• Research in Plant Disease
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• v.15 no.3
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• pp.242-247
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• 2009

To select rotation crops for control of clubroot of Chinese cabbage, potato, corn, soybean, onion and groundsel were planted in the field infected with clubroot pathogen (Plasmodiophora brassicae) in highland area in 2000. In comparison of economical efficiency among rotation crops, potato and onion gained about 16.9 and 14.9 times higher, respectively, than successive cultivation of Chinese cabbage. Resting spore densities of Plasmodiophora brassicae after harvesting rotation crops were in the range of $0.3{\sim}1.2{\times}10^3/g$ soil in all cultivated soils with rotation crops while that of successive Chinese cabbage cultivation soil was very high as much as $89.3{\times}10^3/g$ soil. And disease severity of Chinese cabbage clubroot was 4.9, 20.2, 24.4, 25.1 and 27.8% in onion, soybean, potato, corn, and groundsel cultivation plot, respectively, while that of successive Chinese cabbage cultivation plot was very high as 77.8%. Effect of rotation period of onion, potato, soybean on disease control was investigated from 2002 to 2005. Resting spore densities of Plasmodiophora brassicae after cultivating rotation crops were decreased until $2^{nd}$ year and maintained low density at $3^{rd}$ year in all plots, while that of successive Chinese cabbage cultivation plot was increased 2.6 to 23.6 times for three years. When Chinese cabbage was rotation-cultivated with potato, soybean and onion for three years, disease severities of Chinese cabbage clubroot decreased 92 to 4.4%, 72 to 10.4% and 72 to 12.2%, respectively, while that of successive Chinese cabbage cultivation plot maintained 100%. As the rotation period increased, the yields of Chinese cabbage increased, while that of successive Chinese cabbage cultivation plot decreased. At $3^{rd}$ year, Chinese cabbage with high quality could be much more produced 2,205, 2,493 and 2,476 g in potato, soybean and onion cultivation plot, respectively, than 95 g in successive Chinese cabbage cultivation plot.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.3
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• pp.152-163
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• 2001

Based upon the sedimentological, geochemical and micropaleontological analyses of two sediment cores from the Antarctic Peninsula (AP), three distinct lithological units can be recognized: (1) ice-proximal an/or ice-distal diamictons in the lower part of the cores, accumulated just seaward of the grounding line of the ice shlef until 11,000 yrs BP; (2) diatomaceous mud between 6,000 and 2,500 yrs BP in the middle part, resulted from a large influx of organic materials by enhanced production of open marine condition; (3) diatomaceous sandy mud since 2,500 yrs BP, characterized by an increase in sand content and decrease in TOC and diatom abundance in the lower layers, which reflects the formation of more extensive and seasonally persistent sea ice. Based on the C-14 radiocarbon dating, the sub-ice shlef deposition of the diamicton on the AP western shelf completed around 11,000 yrs BP. Colder condition was reinstated between 12,800 and 11,600 BP with a dropin TOC content and diatom abundance, which is coincident with the Younger Dryas event in the North Atlanticregion. At this time, the ice shelf, that is now absent in the study area, appears to advance as evidenced by an abrupt increase in sea-ice taxa. A climatic optimum is recognized between 9,000 and 2,500 BP, coincide witha mid-Holocene climatic optimum 'Hypsithermal Warm Period' from the other Antarctic sites. During this time, diatomaceous mud accumulated by a large influx of organic materials by enhanced production occurred in openmarine condition. Around 2,500 BP, diatomaceous sandy mud reflects the formation of more extensive and seasonally persistent sea ice, coincident with the onset of the Neoglacial in the Antarctic. Our results provide evidence of climatic change from the Antarctic Peninsula`s western shelf that helps in determining the existence and timing of Holocene milennial-scale climatic events in the Southern Hemisphere.