• Korean Journal of Environmental Agriculture
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• v.33 no.1
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• pp.52-56
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• 2014

BACKGROUND: It is known that impacts of climate change on damage occurrence by insect pests and diseases are increasing. The negative effects of climate change on production will threaten our food security. It is needed that on the basis of analysis of the impacts, proper strategies in response to climate change are developed. METHODS AND RESULTS: The objective of this paper is to estimate impacts of climate change on rice damage occurrence by insect pests and diseases, using the panal model which analyzes both cross-section data and time series data. The result of an analysis on impacts of climate change on rice damage occurrence by pest insect and disease showed that the damage occurrence by Rice leaf roller and Rice water weevil increased if temperature increased, and damage occurrence by Stripe, Sheath blight, and Leaf Blast increased if precipitation(or amount of sunshine) increased(or decreased). CONCLUSION: Adaptation strategies, supplying weather forecasting information by region, developing systematical strategies for prevention of damage occurrence by pest insect and disease, analyzing the factors of damage occurrence by unexpected pest insect and disease, enforcing international cooperation for prevention of damage occurrence are needed to minimize the impacts of damage occurrence on rice production.

• Korean Journal of Agricultural Science
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• v.12 no.2
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• pp.206-241
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• 1985

Attempts to search infection period, infection speed in the tissue of neck blast of rice plant, location of inoculum source and effects of several conditions about the leaf sheath of rice plants for neck blast incidence have been made. 1. The most infectious period for neck blast incidence was the booting stage just before heading date, and most of necks have been infected during the booting stage and on heading date. But $Indica{\times}Japonica$ hybrid varieties had shown always high possibility for infection after booting stage. 2. Incubation period for neck blast of rice plants under natural conditions had rather a long period ranging from 10 to 22 days. Under artificial inoculation condition incubation period in the young panicle was shorter than in the old panicle. Panicles that emerged from the sheath of flag leaf had long incubation period, with a low infection rate and they also shown slow infection speed in the tissue. 3. Considering the incubation period of neck blast of rice plant, we assumed that the most effective application periods of chemicals are 5-10 days for immediate effective chemicals and 10-15 days for slow effective chemicals before heading. 4. Infiltration of conidia into the leaf sheath of rice plant carried out by saturation effect with water through the suture of the upper three leaves. The number of conidia observed in the leaf sheath during the booting stage were higher than those in the leaf sheath during other stages. Ligule had protected to infiltrate of conidia into the leaf sheath. 5. When conidia were infiltrated into the leaf sheath, the highest number of attached conidia was observed on the panicle base and panicle axis with hairs and degenerated panicle, which seemed to promote the infection of neck blast. 6. The lowest spore concentration for neck blast incidence was variable with rice varietal groups. $Indica{\times}Japonica$ hybrid varieties were infected easily compared to the Japonica type varieties, especially. The number of spores for neck blast incidence in $Indica{\times}Japonica$ hybrid varieties was less than 100 and disease index was higher also in $Indica{\times}Japonica$ hybrid than in Japonica type varieties. 7. Nitrogen content and silicate content were related with blast incidence in necks of rice plants in the different growing stage changed during growing period. Nitrogen content increased from booting stage to heading date and then decreased gradually as time passes. Silicate content increased from booting stage after heading with time. Change of these content promoted to increase neck blast infection. 8. Conidia moved to rice plant by ascending and desending dispersal and then attached on the rice plant. Conidia transfered horizontally was found very negligible. So we presumed that infection rate of neck blast was very low after emergence of panicle base from the leaf sheath. Also ascending air current by temperature difference between upper and lower side of rice plant seemed to increase the liberation of spores. 9. Conidial number of the blast fungus collected just before and after heading date was closely related with neck blast incidence. Lesions on three leaves from the top were closely related with neck blast incidence, because they had high potential for conidia formation of rice blast fungus and they were direct inoculum sources for neck blast. 10. The condition inside the leaf sheath was very favorable for the incidence of neck blast and the neck blast incidence in the leaf sheath increased as the level of fertilizer applied increased. Therefore, the infection rate of neck blast on the all panicle parts such as panicle base, panicle branches, spikelets, nodes, and internodes inside the leaf sheath didn't show differences due to varietal resistance or fertilizers applied. 11. Except for others among dominant species of fungi in the leaf sheath, only Gerlachia oryzae appeared to promote incidence of neck blast. It was assumed that days for heading of varieties were related with neck blast incidence.

• Korean Journal Plant Pathology
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• v.11 no.4
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• pp.348-352
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• 1995

Severe gray mold neck rot of onion occurred in most farmers' fields in the southern part of Korea, and 20∼50% of onions were infected by the disease at Goheung, Chonnam, in 1994. Symptoms of the disease appeared on the lower leaves near the soil surface in late February. The symptoms initially appeared as yellowish blotch with compact gray mold on the surface of the infected leaves and developed to blast of the aboveground parts of onions. As brown to dark brown symptoms progressed around the necks of onion later, the bulbs were rotting gradually. Botrytis sp. repeatedly isolated from the lesions produced the typical symptom on the neck of healthy onion 7 days after wound inoculation of conidial suspension of the fungus. The fungus reisolated from the bulbs was identified as Botrytis allii Munn based on the morphological and cultural characteristics and pathogenicity. This is first report of a gray mold neck rot of onion in Korea.

• Korean Journal Plant Pathology
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• v.12 no.1
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• pp.121-128
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• 1996

농업 기상 자료의 수집 및 식물병 예찰 절차를 통합한 시스템을 -32비트 개인용 컴퓨터 운영 체계인 OS/2에서 개발하였다. 통합 시스템은 무인기상관측기(AWS)로부터 자료 수집을 하는 절차, 준실시간 기상자료로부터 병예찰을 하는 절차, 기상 정보와 병예찰 정보를 글과 그림으로 출력하는 절차의 세 부분으로 나뉘어 있다. 통합 시스템은 여러 지역의 실시간 기상 자료를 수집하며 기상 자료를 이용하여 각 지역의 병예찰 정보를 즉시 생성한다. 본 연구에서는 기상 자료를 이용한 병예찰 모형의 예로서 도열병 예찰 시뮬레이션 모형을 사용하였다. 또한 식물병 예찰을 위하여 무인기상관측기가 갖추어져야 하는 최소한의 요구 사항을 검토하였다. 본 시스템은 각종 식물병 예찰 모형의 개발과 관련하여 각 모형의 구동을 위하여 쓰여질 수 있을 것이다. 현재 각 농촌진흥원과 지도소에는 많은 수의 무인기상관측기가 설치되어 있으므로 이를 이용하여 본 시스템을 실용화 할 수 있을 것이다.

• Research in Plant Disease
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• v.29 no.1
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• pp.39-44
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• 2023

To diagnose lily fasciation, lily bulbs showing fasciation were collected from several greenhouses in Jeju Island, South Korea. Bacteria were isolated from the lily bulbs and amplified with both primers for fasA in plasmid and for putative glycosyltransferase epsH gene in chromosome of Rhodococcus fascians. Three bacterial isolates were detected with the P450 primer set and identified as R. fascians by NCBI blast analysis. Twelve bacterial isolates were identified as R. fascians using RS02785 primer set, including the three bacterial isolates identified as the same pathogen using the P450 primer set. Pathogenicity of these bacterial strains identified as R. fascians was demonstrated. Apparent symptoms were observed on wounded lily leaves after inoculation with each bacterial suspension whereas no symptom was found on lily leaves treated with H₂O. Furthermore, bacteria re-isolated from wounded sites were identified as R. fascians. Based on the results, these two sets of primers are recommended for quarantine of R. fascians.

• Korean Journal of Organic Agriculture
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• v.13 no.3
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• pp.291-300
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• 2005

Diseases were surveyed in 5 Rice paddy field areas of Organic paddy field and conventional paddy field. The 3 major diseases, rice leaf blast, bacterial leaf blight and sheath blight in rice were surveyed at duck raising, rice bran and conventional rice paddy field. They were serious in duck raising paddy field, rice bran paddy field more than conventional paddy field. The Ilpum variety were infected seriously more than Chucheong. At the effectivity test of the environment-friendly substance for the rice-seed sterilization, 1000-times diluted brown-rice vinegar showed controlling effect against Bakanae disease, and germination rate also was good. There was no Weeds Control efficacy by cultivating of hairy vetch in rice paddy field. However, extract of hairy vetch Leaf and root repressed the germinating of lettuce seed.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2005.09a
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• pp.407-411
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• 2005

KUGI (Korean UniGene Information) database contains the annotation information of the cDNA sequences obtained from the disease samples prevalent in Korean. A total of about 157,000 5'-EST high throughput sequences collected from cDNA libraries of stomach, liver, and some cancer tissues or established cell lines from Korean patients were clustered to about 35,000 contigs. From each cluster a representative clone having the longest high quality sequence or the start codon was selected. We stored the sequences of the representative clones and the clustered contigs in the KUGI database together with their information analyzed by running Blast against RefSeq, human mRNA, and UniGene databases from NCBI. We provide a web-based search engine fur the KUGI database using two types of user interfaces: attribute-based search and similarity search of the sequences. For attribute-based search, we use DBMS technology while we use BLAST that supports various similarity search options. The search system allows not only multiple queries, but also various query types. The results are as follows: 1) information of clones and libraries, 2) accession keys, location on genome, gene ontology, and pathways to public databases, 3) links to external programs, and 4) sequence information of contig and 5'-end of clones. We believe that the KUGI database and search system may provide very useful information that can be used in the study for elucidating the causes of the disease that are prevalent in Korean.

• Mycobiology
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• v.38 no.3
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• pp.166-170
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• 2010

Gummy stem blight is a major foliar disease of muskmelon (Cucumis melo L.). In this study, morphological characteristics and rDNA internal transcribed spacer (ITS) sequences were analyzed to identify the causal organism of this disease. Morphological examination of the Jeonbuk isolate revealed that the percentage of monoseptal conidia ranged from 0% to 10%, and the average length $\times$ width of the conidia was 70 ($\pm$ 0.96) $\times$ 32.0 ($\pm$ 0.15) ${\mu}m$ on potato dextrose agar. The BLAST analysis showed nucleotide gaps of 1/494, 2/492, and 1/478 with identities of 485/492 (98%), 492/494 (99%), 491/494 (99%), and 476/478 (99%). The similarity in sequence identity between the rDNA ITS region of the Jeonbuk isolate and other Didymella bryoniae from BLAST searches of GenBank was 100% and was 95.0% within the group. Nucleotide sequences of the rDNA ITS region from pure culture ranged from 98.2% to 99.8%. Phylogenetic analysis with related species of D. bryoniae revealed that D. bryoniae is a monophyletic group distinguishable from other Didymella spp., including Ascochyta pinodes, Mycosphaerella pinodes, M. zeae-maydis, D. pinodes, D. applanata, D. exigua, D. rabiei, D. lentis, D. fabae, and D. vitalbina. Phylogenetic analysis, based on rDNA ITS sequence, clearly distinguished D. bryoniae and Didymella spp. from the 10 other species studied. This study identified the Jeonbuk isolate to be D. bryoniae.

• The Plant Pathology Journal
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• v.34 no.2
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• pp.126-138
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• 2018

Rice blast caused by Magnaporthe oryzae is a major disease. In the present study, we aimed to identify and evaluate the novel bacterial isolates from rice rhizosphere for biocontrol of M. oryzae pathogen. Sixty bacterial strains from the rice plant's rhizosphere were tested for their biocontrol activity against M. oryzae under in vitro and in vivo. Among them, B. amyloliquefaciens had significant high activity against the pathogen. The least disease severity and highest germination were recorded in seeds treated with B. amyloliquefaciens UASBR9 (0.96 and 98.00%) compared to untreated control (3.43 and 95.00%, respectively) under in vivo condition. These isolates had high activity of enzymes in relation to growth promoting activity upon challenge inoculation of the pathogen. The potential strains were identified based on 16S rRNA gene sequencing and dominance of these particular genes were associated in Bacillus strains. These strains were also confirmed for the presence of antimicrobial peptide biosynthetic genes viz., srfAA (surfactin), fenD (fengycin), spaS (subtilin), and ituC (iturin) related to secondary metabolite production (e.g., AMPs). Overall, the results suggested that application of potential bacterial strains like B. amyloliquefaciens UASBR9 not only helps in control of the biological suppression of one of the most devastating rice pathogens, M. grisea but also increases plant growth along with a reduction in application of toxic chemical pesticides.

• Korean journal of applied entomology
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• v.9 no.1
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• pp.15-20
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• 1970

An investigation was carried out to know the relationship between resistance of rice varieties to blast disease and the chemical components, especially total nitrogen and total sugars, in the rice plants. The results sic summarized as follow: 1) The nitrogen contents in the resistant variety were less than those of susceptible one, and sugar contents were reversed. Accordingly, the C/N ratio in the resistant variety was higher than that obtained by susceptible one. 2) The free amino acids contents, especially, Glutamine, Valine, Leusine and Iso-leusine, in the resistant varieties were more than those of the susceptible varieties. 3) The starch synthetic activity of rice leaves in the resistant varieties was higher than that of susceptible one in fructose and glucose solutions, but it was reversed in sucrose solution. 4) When more nitrogen was dressed, the total nitrogen content of rice leaves was increased than the ordinary dressing. The rate of increase in nitrogen content in resistant variety was lower than those of the susceptible. The total sugar content of rice plants dressed more nitrogen was decreased at early tillering stage, but increased at maximum tillering stage. It seemed that the rate of increase of total sugar in the resistant variety was higher than those of the susceptible.