• The Plant Pathology Journal
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• v.29 no.1
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• pp.10-16
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• 2013

Hevea brasiliensis is a natural source of rubber and an important plantation tree species in Malaysia. Leaf blight disease caused by Fusicoccum substantially reduces the growth and performance of H. brasiliensis. The aim of this study was to use a combination of both morphological characteristics and molecular data to clarify the taxonomic position of the fungus associated with leaf blight disease. Fusicoccum species were isolated from infected leaves collected from plantations at 3 widely separated locations - Selangor, Perak, and Johor states - in Peninsular Malaysia in 2010. All the isolates were identified according to their conidial patterns and DNA sequences generated from internal transcribed spacers (ITS1 and ITS2), the 5.8S rRNA, and an unknown locus (BotF15) containing microsatellite repeats. Based on taxonomic and sequence data, Neofusicoccum ribis was identified as the main cause of leaf blight disease in H. brasiliensis in commercial plantations in Malaysia. A pathogenicity trial on detached leaves further confirmed that N. ribis causes leaf blight disease. N. ribis is an important leaf pathogen, and its detection in Malaysia has important implications for future planting of H. brasiliensis.

• The Plant Pathology Journal
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• v.17 no.1
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• pp.45-51
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• 2001

A root rot/vine decline disease occurred naturally on bottle gourd-stocked watermelon, melon, oriental melon and squash grown in greenhouses, but not on these plants grown in fields. Self-rooted watermelon, cucumber, pumpkin and luffa were also proven to be hosts of the pathogen by artificial inoculation in this experiment. The pathogen was identified as Monosporascus cannonballus by comparing microscopic characteristics of fungal structures with those of previously identified fungal strains. Our field investigations showed that the temperature and electric conductivity of soil in infected greenhouses were higher and the soil moisture content was lower than in noninfected greenhouses. To investigate soil-environmental factors affecting disease development, greenhouse trials and inoculation experiments were conducted. The host plants inoculated and grown under conditions of high soil temperature and electrical conductivity ($35\pm2^{\circ}$, 3.2-3.5 mS) and with low soil moisture content (pF 3.0-4.5) were most severely damaged by the fungal disease. Since plants growing in greenhouses ae usually exposed to such environmental conditions, this may be the reason why the monosporascus root rot/vine decline disease has occurred only on cucurbits cultivated in greenhouses but not in field conditions.

• Smart Media Journal
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• v.13 no.8
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• pp.16-25
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• 2024

Recently, there has been a growing emphasis on identifying both known and unknown diseases in plant disease recognition. In this task, a model trained only on images of known classes is required to classify an input image into either one of the known classes or into an unknown class. Consequently, the capability to recognize unknown diseases is critical for model deployment. To enhance this capability, we are considering three factors. Firstly, we propose a new logits-based scoring function for unknown scores. Secondly, initial experiments indicate that a compact feature space is crucial for the effectiveness of logits-based methods, leading us to employ the AM-Softmax loss instead of Cross-entropy loss during training. Thirdly, drawing inspiration from the efficacy of transfer learning, we utilize a large plant-relevant dataset, PlantCLEF2022, for pre-training a model. The experimental results suggest that our method outperforms current algorithms. Specifically, our method achieved a performance of 97.90 CSA, 91.77 AUROC, and 90.63 OSCR with the ResNet50 model and a performance of 98.28 CSA, 92.05 AUROC, and 91.12 OSCR with the ConvNext base model. We believe that our study will contribute to the community.

• The Plant Pathology Journal
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• v.32 no.1
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• pp.8-15
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• 2016

To identify a novel biopesticide controlling rice blast disease caused by Magnaporthe oryzae, 700 plant extracts were evaluated for their inhibitory effects on mycelial growth of M. oryzae. The L. foenum-graecum Herba extract showed the lowest inhibition concentration ($IC_{50}$) of $39.28{\mu}g/ml$, which is lower than the $IC_{50}$ of blasticidin S ($63.06{\mu}g/ml$), a conventional fungicide for rice blast disease. When treatments were combined, the $IC_{50}$ of blasticidin S was dramatically reduced to $10.67{\mu}g/ml$. Since ABC transporter genes are involved in fungicide resistance of many organisms, we performed RT-PCR to investigate the transcriptional changes of 40 ABC transporter family genes of M. oryzae treated with the plant extract, blasticidin S, and tetrandrine, a recognized ABC transporter inhibitor. Four ABC transporter genes were prominently activated by blasticidin S treatment, but were suppressed by combinational treatment of blasticidin S with the plant extract, or with tetrandrine that didn't show cellular toxicity by itself in this study. Mycelial death was detected via confocal microscopy at 24 h after plant extract treatment. Finally, subsequent rice field study revealed that the plant extract had high control efficacy of 63.3% and should be considered a biopesticide for rice blast disease. These results showed that extract of L. foenum graecum Herba suppresses M. oryzae ABC transporter genes inducing mycelial death and therefore may be a potent novel biopesticide.

• Research in Plant Disease
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• v.9 no.2
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• pp.104-105
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• 2003

• Research in Plant Disease
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• v.30 no.1
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• pp.1-12
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• 2024

Since the List of Plant Diseases in Korea (DisList) was first published in 1986, the 6th edition appeared 36 years later. In 2023, the 6.1 edition, a revised and improved version of the 6th edition, was released to the public on the web free of charge. The contents of DisList increased, with the number of hosts increasing from 437 taxa to 1,420 taxa and the number of disease species increasing from 1,539 to 6,680. Among these, tree diseases are 3,586 species and their hosts include 504 taxa, providing much help to experts who need them. Meanwhile, the importance of accurate disease names continues to grow with the legalization of tree care, but many disease names are still inappropriate or misused, causing confusion. Disease names that do not follow the naming regulations are still registered, and even if the same pathogen infects hosts of the same taxa, the disease names are given differently, and there are many disease names that do not indicate the characteristics of the disease. Also, there are diseases reported without Korean names. In order to make DisList better, the review committee for disease names should establish the regulations to review and register disease names, and establish a system to review new disease names before publishing papers.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2002.04b
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• pp.188-188
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• 2002

• The Plant Pathology Journal
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• v.20 no.3
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• pp.172-176
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• 2004

Bacterial isolates TRL2-3 and TRK2-2 showing anti-fungal activity in vitro test against some plant pathogens were identified as Pseudomonas putida and Micrococcus luteus, respectively. Pre-treatment with both bacterial isolates at the concentration 1.0$\times$ $10^7$ and $10^6$cfu/ml in the rhizosphere could trigger induced systemic resistance in the aerial part of cucumber plants against anthracnose caused by Colletotrichum orbiculare. However, the pre-treatment with the higher concentration at 1.0 $\times$ $10^8$ cfu/ml of both isolates could not induce resistance after challenge inoculation with C. orbiculare. As a positive control, the treatment with DL-3 amino butyric acid caused a remarkable reduction of disease severity whereas the lesions on the leaves of untreated plants developed apparently after the fungal inoculation. From these results, it was recomended that disease control using both bacterial isolates inducing systemic resistance in the field where chemical application is forbid.

• Journal of Ginseng Research
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• v.41 no.3
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• pp.307-315
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• 2017

Background: Red-skin root disease has seriously decreased the quality and production of Panax ginseng (ginseng). Methods: To explore the disease's origin, comparative analysis was performed in different parts of the plant, particularly the epidermis, cortex, and/or fibrous roots of 5-yr-old healthy and diseased red-skin ginseng. The inorganic element composition, phenolic compound concentration, reactive oxidation system, antioxidant concentrations such as ascorbate and glutathione, activities of enzymes related to phenolic metabolism and oxidation, and antioxidative system particularly the ascorbate-glutathione cycle were examined using conventional methods. Results: Aluminum (Al), iron (Fe), magnesium, and phosphorus were increased, whereas manganese was unchanged and calcium was decreased in the epidermis and fibrous root of red-skin ginseng, which also contained higher levels of phenolic compounds, higher activities of the phenolic compound-synthesizing enzyme phenylalanine ammonia-lyase and the phenolic compound oxidation-related enzymes guaiacol peroxidase and polyphenoloxidase. As the substrate of guaiacol peroxidase, higher levels of $H_2O_2$ and correspondingly higher activities of superoxide dismutase and catalase were found in red-skin ginseng. Increased levels of ascorbate and glutathione; increased activities of $\text\tiny L$-galactose 1-dehydrogenase, ascorbate peroxidase, ascorbic acid oxidase, and glutathione reductase; and lower activities of dehydroascorbate reductase, monodehydroascorbate reductase, and glutathione peroxidase were found in red-skin ginseng. Glutathione-S-transferase activity remained constant. Conclusion: Hence, higher element accumulation, particularly Al and Fe, activated multiple enzymes related to accumulation of phenolic compounds and their oxidation. This might contribute to red-skin symptoms in ginseng. It is proposed that antioxidant and antioxidative enzymes, especially those involved in ascorbate-glutathione cycles, are activated to protect against phenolic compound oxidation.

• The Plant Pathology Journal
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• v.20 no.1
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• pp.67-74
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• 2004

A complete understanding of the epidemiological factors required for optimum for disease development facilitates the design of effective and reliable screening techniques and also disease prediction models. An attempt was made to study the effects of different temperatures ($15-35^{\circ}C$) and leaf wetness periods (4-24 h) on the development of late leaf spot (LLS) in three groundnut genotypes differing in their susceptibility to LLS infection. Irrespective of the genotype, the disease progress evaluated based on different components of resistance was maximum between $15-20^{\circ}C$ and minimum between $20-25^{\circ}C$. At temperatures $\geq$$30^{\circ}C$, LLS development was insignificant. The overall severity of LLS increased with an increase in the leaf wetness period from 4 h to 12 h a day. Further increase of wetness period to 16 h resulted in a rapid increase in the severity. Thereafter, the disease severity gradually decreased with an increase in the wetness period. The effect of temperature and wetness periods on the individual component of disease quantification was not uniform compared between genotypes with different levels of susceptibility/resistance to LLS infection. The results of this study indicate that temperature and leaf wetness period are critical in late leaf spot screening programs since the expression of disease symptoms measured from disease initiation till defoliation, varied differently in the test genotypes with respect to change in these two parameters.