• Korean Journal Plant Pathology
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• v.13 no.3
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• pp.139-144
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• 1997

A destructive collar rot of apple caused by a species of Phytophthora has widely occurred in Kyungbuk and less extended in Chungbuk, Chungnam and Chunbuk provinces of Korea. Significantly higher incidence of the disease was observed on cv. Fuji when M26 or M9 was used as dwarfing stocks. Incidence of the disease at several orchards in Uisung, Kunwi, Yesan and Muju ranged from 45 to 80%. Twenty-five isolates of the causal fungus were collected and all isolates were identified as P. cactorum on the basis of their cultural and morphological characters. The fungus produced markedly papillate and broadly ovoid deciduous sporangia both on agar and in water, and a short pedicel was attached to each sporangium. Oospores were readily formed on clarified V8 agar by single isolates and all the antheridia were paragynous. The fungus neither grew nor produced oospores under 5 and over 33$^{\circ}C$. The destructive collar rot of apple caused by P. cactorum has not been reported in Korea previously.

• Korean journal of applied entomology
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• v.9 no.2
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• pp.81-84
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• 1970

The occurence of apple canker in the three main apple growing areas including Yesan, Chungju and Taegu was investigated during the four years from 1967 to 1970. According to the survey, about 30 percent of apple plants was infected with canker organisms and more the disease occurred in older plants in comparison with younger ones. Jonathan was said to be highly susceptible among five varieties observed. Main trunks or main branches had more canker lesions than those of twigs or of side branches. The survey showed that application of higher nitrogenous fertilizer without boric acid predisposed to the disease together with sandy soil.

• Journal of Korean Academy of Dental Administration
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• v.10 no.1
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• pp.42-52
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• 2022

This study aimed to investigate the association of lifestyle with the copy number of periodontal pathogens. This retrospective study collected electronic health records of 102 subjects with periodontitis, including reports of bacterial genetic tests and lifestyle questionnaires. The five pathogens were analyzed as follows: Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Prevotella intermedia, and Fusobacterium nucleatum. The lifestyle questionnaire included age, sex, oral hygiene management, smoking, drinking, exercise, dietary, snacks, water intake, and sleeping time. An independent t-test or ANOVA was performed to compare the copy number of periodontal pathogens according to lifestyle (α=0.05). The copy numbers of P. gingivalis and F. nucleatum were significantly higher than those of other strains. The copy number of T. forsythia in patients who exercised was 54% lower than in those who did not (p=0.009). Other lifestyle factors did not affect the number of bacteria. Exercise habits among the lifestyles showed a association with the number of specific oral bacteria. This result suggests that a lifestyle questionnaire is essential in clinical situation and necessary to prevent and treat the periodontal disease effectively.

• Research in Plant Disease
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• v.29 no.2
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• pp.193-199
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• 2023

The apple stem grooving virus (ASGV) is one of the most harmful latent viruses infecting pear orchards worldwide. To examine the genetic diversity of ASGV in Korean pear orchards, the complete coat protein (CP) gene of five ASGV isolates collected from various regions were identified. The five Korean ASGV isolates showed 88-96% nucleotide identity with the 11 isolates worldwide occurring elsewhere in the world. Phylogenetic analysis of five isolates, as well as the previously sequenced isolates, indicated that the ASGV clusters had no correlation with the host or geographical regions of origin. Recombination analysis showed that one of the five Korean isolates is a recombinant, with a recombination site in the CP gene region (nt 532-708). This study is the first report of natural recombination within the CP gene of ASGV isolates from pears grown in Korea.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2004.10a
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• pp.21-24
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• 2004

See Full Text

• Proceedings of the Zoological Society Korea Conference
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• 2001.10a
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• pp.242.2-242
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• 2001

No Abstract, See Full Text

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2009.12a
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• pp.45-56
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• 2009

Current status on the occurrence and the management of the major disease, insect and mite pests were investigated in the organic or non-chemical pest control orchards from 2005 to 2009. Numbers of certified organic or non-chemical apple orchards were increased from 14 in 2005 to 78 in 2008. Severe damages on leaves and fruits occurred by the several diseases such as marssonina blotch, bitter rot, white rot, sooty blotch and flyspeck, and the several insect pests such as apple leaf-curling aphid, woolly apple aphid, oriental fruit moth and peach fruit moth on the almost certified organic or non-chemical pest control orchards. About 10 and 18 environmental-friendly materials were used to control diseases and insect or mite pests respectively. But, lime sulfur and bordeaux mixture to diseases and machine oil, plant oil mixed with egg yolk, and pheromone mating disruptions to insect pests were effective to control under the adequate conditions. At present, it is extremely difficult to produce organic apples in Korea. Growers must consider about and solve so many conditions on the cultivar, weather, local site, marketing and so on, before when they decide to change from conventional or IPM(Integrated Pest Management) to organic or non-chemical pest control orchards.

• Journal of Broadcast Engineering
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• v.25 no.2
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• pp.208-217
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• 2020

The classification of plant diseases by images captured by a camera sensor has been studied over past decades. A method that has gained much interest is to use image segmentation, from which statistical features are derived and analyzed by machine learning. Recently, deep learning has been adopted in this area. However, image segmentation is still a difficult task to achieve stable performance due to a variety of environmental variations. The end-to-end learning in neural network has a demerit that train images may be different from real images acquired in outdoor fields. To solve these problems, we propose superpixel-based disease classification method using end-to-end CNN (convolutional neural network) learning. Based on experiments performed on PlantVillage apple images, the classification accuracy is 98.29% and 92.43% for full-image and superpixel. As well, the multivariate F1-score is (0.98, 0.93). Therefore we validate that the method of using superpixel is comparable to that of full-image.

• The Plant Pathology Journal
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• v.34 no.5
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• pp.445-450
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• 2018

Bacteriophages, bacteria-infecting viruses, have been recently reconsidered as a biological control tool for preventing bacterial pathogens. Erwinia amylovora and E. pyrifoliae cause fire blight and black shoot blight disease in apple and pear, respectively. In this study, the bacteriophage phiEaP-8 was isolated from apple orchard soil and could efficiently and specifically kill both E. amylovora and E. pyrifoliae. This bacteriophage belongs to the Podoviridae family. Whole genome analysis revealed that phiEaP-8 carries a 75,929 bp genomic DNA with 78 coding sequences and 5 tRNA genes. Genome comparison showed that phiEaP-8 has only 85% identity to known bacteriophages at the DNA level. PhiEaP-8 retained lytic activity up to $50^{\circ}C$, within a pH range from 5 to 10, and under 365 nm UV light. Based on these characteristics, the bacteriophage phiEaP-8 is novel and carries potential to control both E. amylovora and E. pyrifoliae in apple and pear.

• The Plant Pathology Journal
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• v.37 no.4
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• pp.404-412
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• 2021

Despite the plant microbiota plays an important role in plant health, little is known about the potential interactions of the flower microbiota with pathogens. In this study, we investigated the microbial community of apple blossoms when infected with Erwinia amylovora. The long-read sequencing technology, which significantly increased the genome sequence resolution, thus enabling the characterization of fire blight-induced changes in the flower microbial community. Each sample showed a unique microbial community at the species level. Pantoea agglomerans and P. allii were the most predominant bacteria in healthy flowers, whereas E. amylovora comprised more than 90% of the microbial population in diseased flowers. Furthermore, gene function analysis revealed that glucose and xylose metabolism were enriched in diseased flowers. Overall, our results showed that the microbiome of apple blossoms is rich in specific bacteria, and the nutritional composition of flowers is important for the incidence and spread of bacterial disease.