• Journal of Korean Society of Forest Science
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• v.98 no.5
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• pp.593-601
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• 2009

Forest disturbances including forest fire, insect pests and diseases, landslides, and forest conversion from 1976 to 2005 were investigated to trace the changes of major forest disturbance agents and their characteristics over time in accordance with changes in natural and social environment in South Korea. While the damaged area by insect pests and diseases continuously decreased for the past 30 years, damaged areas by forest fire and landslide were fluctuating through years. The interval of large forest fires has become shorter with increased tree volume. The precipitation between January and April were significantly correlated with large fire occurrences as Pearson's correlation coefficient -0.400 (P=0.029). The composition of major insect pests and diseases damaging Korean forests has been changed continuously, and become more diversified. While damages by pine caterpillar (Dendrolimus spectabilis) and pine needle gall midge (Thecodiplosis japonensis) decreased, damage by introduced pests has been more serious recently. The change of precipitation pattern that brought more localized heavy rain or powerful typhoon resulted in the recent increase in landslide areas. The major land uses to induce forest conversion have been changed, reflecting the changes in industrial structure in South Korea as agriculture and mining in 1970s, mining and golf ranges classified in pasture in 1980s, and road and housing construction in 1990s and 2000s. Changes in forest disturbance patterns in South Korea show that a country's industrial development is jointly working with global warming on forest stand dynamics. Altering energy structure and land use pattern induced by industrial development accumulates forest volume and reforms microenvironments on forest floor, interacting with climate change, inducing shorter interval of large forest fire and changes in major species composition of forest insect pests and diseases.

• The Plant Pathology Journal
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• v.26 no.1
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• pp.100-100
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• 2010

• The Plant Pathology Journal
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• v.25 no.4
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• pp.435-435
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• 2009

• The Plant Pathology Journal
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• v.27 no.1
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• pp.98-98
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• 2011

• The Plant Pathology Journal
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• v.26 no.4
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• pp.424-424
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• 2010

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2002.11a
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• pp.53.1-53
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• 2002

• Journal of Forest and Environmental Science
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• v.36 no.3
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• pp.255-258
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• 2020

Pine wilt disease (PWD) caused by pine wood nematode (PWN), Bursaphelenchus xylophilus, which is transmitted by Monochamus alternatus and M. saltuarius, is a serious threat to coniferous forests in the Northern Hemisphere, including Korea. The efficacy of abamectin and emamectin benzoate for preventing the PWD in the field and its effect on the vectors Monochamus alternatus and M. saltuarius (Coleoptera: Cerambycidae) were evaluated. An experimental plot was delimited, of which consists of Japanese red pine (Pinus densiflora) forest in South Korea, and trunk injection trials were made with abamectin and emamectin benzoate. Branches of each tree were collected, and are subsequently subjected to the analysis of residues for both nematicides. Results obtained in this study showed that abamectin and emamectin benzoate showed over 90% mortality at the recommended concentration after 6 days and 8 days, respectively. Consequently, it was found that both insecticides have a higher effect on the susceptibility and persistence of two vectors of PWD, M. alternatus and M. saltuarius feeding on branches of the trees, and its application by trunk injection is confirmed as an option for pine wilt disease management programs in Korea.

• The Plant Pathology Journal
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• v.24 no.2
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• pp.159-163
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• 2008

Accurate identification of pine wood nematode, Bursaphelenchus xylophilus is a prerequisite to diagnose the pine wilt disease. However, a fungivorous nematode, B. mucronatus is highly similar to B. xylophilus and it is difficult to differentiate these two species by morphological features. A molecular diagnosis method, ITSRFLP was applied for the identification of B. xylophilus and B. mucronatus from Korea. Genomic DNA was extracted from a single individual nematode and ITS DNA was amplified by PCR. The size of PCR product was approximately 900bp and the sequence data were obtained after cloning. Amplified ITS was digested by 5 different restriction enzymes (Rsa I, Hae III, Msp I, Hinf I, and Alu I) and provided a discriminatory profile for B. xylophilus and B. mucronatus. Besides, B. mucro- natus was determined to have 2 different genotypes, East Asian type and European type also clearly separated by Rsa I and Hae III digestion. European type of B. mucronatus is recently collected from Pinus koraiensis and has not been reported before. ITS sequnce data were analyzed by Restriction Mapper program and the result supported ITS-RFLP pattern. These data indicated that PCRRFLP method is an accurate and simple way for identification of Bursaphelenchus species.

• Research in Plant Disease
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• v.17 no.1
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• pp.99-101
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• 2011

The ascomycetous fungus Taphrina wiesneri, the pathogen of cherry witches' broom, is highly pathogenic to Prunus yedoensis, the most widely planted cherry trees in Korea as park and roadside trees. A collection of 13 strains of the pathogen in Korea and Japan was characterized by 18S rDNA gene sequence and restriction fragment length polymorphism (RFLP) analysis. In cluster analysis based on 18S rDNA gene sequence the strains were divided into 2 clusters. In RFLP analysis of the rDNA-IGS region using HhaI, the strains were separated into four patterns, B, C, D and G, of which pattern G was new.

• Journal of Microbiology
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• v.45 no.3
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• pp.219-226
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• 2007

Insertion sequence IS1112 is a repetitive element with a relatively high number of copies in Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial blight of rice (Oryza sativa L.). Three new loci of IS1112 were identified in seven Chinese strains of Xoo using a single oligonucleotide primer J3; 5'-GCTCA GGTCAGGTGGCCTGG-3' by insertion-sequence-based polymerase chain reaction (IS-PCR). Among the three new loci of IS1112, two were located in the open-reading frame region of genes fhuA and cirA, which encode TonB-dependent receptors, and the third in ISXo2, another type of insertion sequence in Xoo genome. Three variants of IS1112 were identified in those three loci based on their sequence similarities: two were identical to IS1112a and IS1112b, reported in strain PXO86 from the Philippines, while the third was a new member of IS1112, defined as IS1112d. Inserting IS1112 in gene fhuA caused three bases, GGT, to be duplicated at the target site, but inserting it in gene cirA did not cause any duplication in the target site. The diversity of IS1112 sequence and insertion loci in Xoo genome and their potential effects are discussed.