• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.3
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• pp.33-38
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• 2021

Recently, transfer learning techniques with a base convolutional neural network (CNN) model have widely gained acceptance in early detection and classification of crop diseases to increase agricultural productivity with reducing disease spread. The transfer learning techniques based classifiers generally achieve over 90% of classification accuracy for crop diseases using dataset of crop leaf images (e.g., PlantVillage dataset), but they have ability to classify only the pre-trained diseases. This paper provides with an evaluation scheme on selecting an effective base CNN model for crop disease transfer learning with regard to the accuracy of trained target crops as well as of untrained target crops. First, we present transfer learning models called CDC (crop disease classification) architecture including widely used base (pre-trained) CNN models. We evaluate each performance of seven base CNN models for four untrained crops. The results of performance evaluation show that the DenseNet201 is one of the best base CNN models.

• Research in Plant Disease
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• v.17 no.1
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• pp.44-51
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• 2011

The aim of this study was to develop specific and sensitive PCR-based procedures for simultaneous detection of economically important plant seed infection pathogenic bacteria and virus, Xanthomonns campestris pv. vesicatoria (Xcv), Clavibacter michiganensis subsp. michiganensis (Cmm), Erwinia carotovora subsp. carotovora (Ecc), Pepper mild mottle virus (PMMoV) and Tobacco mild green mosaic virus (TMGMV) in pepper and tomato seeds. Most of pepper and tomato bacterial and virus diseases are responsible for germination and growth obstruction. PCR with arbitral primers: selection of specific primers, performance of PCR with specific primers and determination of the threshold level for pathogens detection. To detect simultaneously the Xcv, Cmm, Ecc, PMMoV and TMGMV in pepper and tomato seeds, five pairs (Cmm-F/R, Ecc-F/R, Xcv-F/R, PMMoV-F/R, TMGMV-F/R) of specific primer were synthesized by primer-blast program. The multiplex PCR for the five pathogens in pepper and tomato seeds could detect specially without interference among primers and/or cDNA of plant seeds and other plant pathogens. The PCR result for pathogen detection using 20 commercial pepper and 10 tomato seed samples, Ecc was detected from 4 pepper and 2 tomato seed samples, PMMoV was detected from 1 pepper seed sample, and PMMoV and TMGMV were simultaneously detected from 1 pepper seed sample.

• Research in Plant Disease
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• v.14 no.2
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• pp.138-141
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• 2008

Cucumber is high valued cash crop, for it is grown during the winter season in plastic house. Recently, virus disease spread widely in cucumber growing area and cause severe income loss. Therefore, occurrence of virus disease on cucumber were surveyed from 2004 to 2006 in Sangju and Gunwi area, Gyeongbuk province. The rate of plastic house which has infected plants was $55.0{\sim}88.6%$. Infection rate was the highest at Sangju in 2006 than others and ranged from 15 to 90.0% per plastic house. The 217 samples showing virus symptom were analyzed by RT-PCR using appropriate detection primer. Zucchini yellow mosaic virus(ZYMV) has the highest infection rate(detected over 85%) and followed by Cucumber green mottle mosaic virus(CGMMV). But Watermelon mosaic virus-2(WMV-2) was not detected in our survey. Therefore, we conclude that ZYMV is major pathogene of virus disease on cucumber. ZYMV induced chlorosis and severe mosaic on the leaves and distortion on the surface of fruits.

• The Korean Journal of Pesticide Science
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• v.12 no.2
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• pp.168-176
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• 2008

Recently damage of rice bakanae disease disseminated by infected seeds increased in paddy field in Korea. For controlling rice bakanae disease, the efficacy of 17 fungicides was assessed by 5 kinds of bioassay, spore germination test (SGT), mycelial growth test, detection test on Komada's medium (KDT), pouch test (PT) and greenhouse test (GT). Among ergosterol biosynthesis inhibiting fungicides, prochloraz showed a high controlling activity in all the assay systems while the others showed very low activity except for $500\;{\mu}g/ml$ of hexaconazole in GT and $500\;{\mu}g/ml$ of triflumizole in KDT. Although benomyl and the mixture of benomyl and thiram showed a good activity at 100 and $500\;{\mu}g/ml$ in SGT and PT, respectively, in GT they did a middle activity. Trifloxystrobin and kresoxim-methyl included in strobilurins showed a good activity even at $20\;{\mu}g/ml$ in KDT as well as a middle activity in SGT. Also a high activity not only at $10\;{\mu}g/ml$ in SGT but also at $100\;{\mu}g/ml$ KDT was detected in thiram. The activity of fludioxonil was confirmed in SGT, KDT and PT. Based on these results, it is very important to determine a bioassay system, because the fungicidal activity against rice bakanae disease was fluctuated depending on a assay systems as well as the mechanism of fungicide.

• The Plant Pathology Journal
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• v.36 no.5
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• pp.418-427
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• 2020

Xanthomonas campestris pv. campestris (Xcc), the pathogen of black rot which is the most destructive disease of Brassica vegetables throughout the world. Here, we reported two novel sequence-characterized amplified region (SCAR) markers (i.e., XccR6-60 and XccR6-67) for the detection of Xcc race 6 via re-alignment of the complete genome sequences of Xcc races/strains/pathovars. The specificity of SCAR primer sets was verified by mean of PCR amplification using the genomic DNA template of Xcc races/strains/pathovars and two other plant infecting bacterial strains. The PCR result revealed that the XccR6-60 and XccR6-67 primer sets amplified 692-bp and 917-bp DNA fragments, respectively, specifically from race 6, while no visible amplification was detected in other samples. In addition, the SCAR primers were highly sensitive and can detect from a very low concentration of genomic DNA of Xcc race 6. However, the complete genome sequence of Xcc race 6 is not yet publicly available. Therefore, the cloning and sequencing of XccR6-60 and XccR6-67 fragments from race 6 provide more evidence of the specificity of these markers. These results indicated that the newly developed SCAR markers can successfully, effectively and rapidly detect Xcc race 6 from other Xcc races/strains/pathovars as well as other plant pathogenic bacteria. This is the first report for race-specific molecular markers for Xcc race 6.

• Korean Journal of Plant Resources
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• v.24 no.5
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• pp.599-603
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• 2011

The incidence rates of postharvest fruit rots of four kiwifruit cultivars which were cultivated under rain-proof tunnel house at a same orchard were examined. Among them, 'Halla-Gold', 'Jecy-Gold' and 'Jecy-Sweet' were new cultivars bred in Korea. The disease incidence was varied with cultivars; 74.8%, 65.3%, 57.1% and 16.2% for 'Hayward', 'Halla-Gold', 'Jecy-Sweet' and 'Jecy-Gold' cultivars, respectively. Two hundred and eighteen isolates were obtained from diseased fruits and identified by mycological and molecular biological methods. Three fungi, Botryspheria dothidea, Diaphorthe actinidiae and Botrytis cinerea, were identified as pathogens of the postharvest fruit rots with detection rates of 95.4%, 4.6% and 2.3%, respectively.

• Research in Plant Disease
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• v.24 no.1
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• pp.81-85
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• 2018

Chinese artichoke (Stachys sieboldii Miq.) belongs to herbaceous perennial plants of Labiatea and is cultivated as edible and medicinal crops in China, Japan and Korea. A Chinese artichoke plant showing virus-like symptoms was collected in Chungju, Korea. Plant sap of the sample was inoculated in Nicotiana tabacum cv. Xanthi-nc, Chenopodium quinoa and Chenopodium amaranticolor. Necrotic local lesions were observed in the inoculated leaves of N. tabacum cv. Xanthi-nc and C. amaranticolor, C. quinoa with systemic chlorotic spots and mosaic symptoms on the upper leaves. The disease reactions on indicator plants suggested that the collected Chinese artichoke sample was mixed-infected with different viruses. We detected three viruses by RT-PCR analysis using genus- and species-specific primer sets for Alfalfa mosaic virus (AMV), Cucumber mosaic virus (CMV) and Tobacco mosaic virus (TMV). This study is the first report of a mixed infection of three viruses in Chinese artichoke in Korea.

• Journal of Ginseng Research
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• v.45 no.4
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• pp.519-526
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• 2021

Background: This study aimed to investigate the effect of cold plasma treatment on the improvement of seed germination and surface sterilization of ginseng seeds. Methods: Dehisced ginseng (Panax ginseng) seeds were exposed to dielectric barrier discharge (DBD) plasma operated in argon (Ar) or an argon/oxygen mixture (Ar/O₂), and the resulting germination and surface sterilization were compared with those of an untreated control group. Bacterial and fungal detection assays were performed for plasma-treated ginseng seeds after serial dilution of surface-washed suspensions. The microbial colonies (fungi and bacteria) were classified according to their phenotypical morphologies and identified by molecular analysis. Furthermore, the effect of cold plasma treatment on the in vitro antifungal activity and suppression of Cylindrocarpon destructans in 4-year-old ginseng root discs was investigated. Results: Seeds treated with plasma in Ar or Ar/O₂ exhibited a higher germination rate (%) compared with the untreated controls. Furthermore, the plasma treatment exhibited bactericidal and fungicidal effects on the seed surface, and the latter effect was stronger than the former. In addition, plasma treatment exhibited in vitro antifungal activity against C. destructans and reduced the disease severity (%) of root rot in 4-year-old ginseng root discs. The results demonstrate the stimulatory effect of plasma treatment on seed germination, surface sterilization, and root rot disease suppression in ginseng. Conclusion: The results of this study indicate that the cold plasma treatment can suppress the microbial community on the seed surface root rot in ginseng.

• Korean Journal Plant Pathology
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• v.2 no.2
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• pp.96-101
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• 1986

Total 29 commercial crucifer seed lots were tested for seed transmission of Xanthomonas campestris pv. campestris by seed washing liquid plating assay. One imported cabbage seed lot was found to carry Xanthomonas campestris pv. campestris. Several methods and chemicals for eradication of Xanthomonas campestris pv. campestris in and on the cabbage seed were tested for effectiveness. Soaking cabbage seed in $3\3%$ hydrogen peroxide solution for 30 minutes effectively eradicated Xanthomonas campestris pv. campestris in a naturally infested seed lot. In a field survey, black rot turned out to be an important disease in cabbage in Korea.

• 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.