• The Plant Pathology Journal
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• v.21 no.4
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• pp.406-408
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• 2005

Web blight symptoms were frequently observed on soybean plants grown in a farmer's fields located in Jincheon in Korea during a disease survey in August, 2005. Incidence of the disease was $5-20\%$ infected plants in two of four soybean fields investigated. A total of 31 isolates of Rhizoctonia sp. were obtained from leaves, leaf petioles, and pods of diseased soybean plants. The isolates were identified as Rhizoctonia solani AG-l(IA) by anastomosis test and based on the morphological and cultural characteristics. Three isolates of R. solani AG-l(IA) were tested for pathogenicity to five cultivars of soybean by artificial inoculation. All the isolates induced blight symptoms on the leaves of soybean and formed sclerotia on the lesions, which were similar to those observed in the field. The pathogenicity tests revealed that all the soybean cultivars tested were susceptible to the pathogen. There was no difference in the pathogenicity among the isolates. The present study first reveals that R. solani AG-l(IA) causes web blight of soybean in Korea.

• Korean Journal of Breeding Science
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• v.43 no.4
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• pp.241-251
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• 2011

Bacterial blight(BB) caused by Xanthomonas oryzae pv. oryzae(Xoo) is one of the most economically destructive bacterial diseases of rice in worldwide. Utilization of resistant cultivars carrying resistant gene(s) is relatively an effect method to control this disease. About 34 resistant genes for BB resistance have been identified in many countries. Among them, Xa1 and Xa3 genes against bacterial blight have been incorporated into improved korean japonica rice varieties. Now, Ilmi carrying Xa1 gene and severial cultivars carrying Xa3 gene are widely grown in our country. In recent year, xa5, Xa21 and Xa23 genes are using in rice breeding programs for japonica resistant cultivars to bacterial blight. Resistant cultivars incorporated with a diverse single gene and two, three, or the more major gene necessite in the future.

• The Plant Pathology Journal
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• v.37 no.6
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• pp.543-554
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• 2021

To preventively control fire blight in apple trees and determine policies regarding field monitoring, the Maryblyt ver. 7.1 model (MARYBLYT) was evaluated in the cities of Chungju, Jecheon, and Eumseong in Korea from 2015 to 2020. The number of blossom infection alerts was the highest in 2020 and the lowest in 2017 and 2018. And the common feature of MARYBLYT blossom infection risks during the flowering period was that the time of BIR-High or BIR-Infection alerts was the same regardless of location. The flowering periods of the trees required to operate the model varied according to the year and geographic location. The model predicts the risk of "Infection" during the flowering periods, and recommends the appropriate times to control blossom infection. In 2020, when flower blight was severe, the difference between the expected date of blossom blight symptoms presented by MARYBLYT and the date of actual symptom detection was only 1-3 days, implying that MARYBLYT is highly accurate. As the model was originally developed based on data obtained from the eastern region of the United States, which has a climate similar to that of Korea, this model can be used in Korea. To improve field utilization, however, the entire flowering period of multiple apple varieties needs to be considered when the model is applied. MARYBLYT is believed to be a useful tool for determining when to control and monitor apple cultivation areas that suffer from serious fire blight problems.

• The Plant Pathology Journal
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• v.38 no.4
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• pp.355-365
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• 2022

Erwinia amylovora and E. pyrifoliae are the causative agents of destructive diseases in both apple and pear trees viz. fire blight and black shoot blight, respectively. Since the introduction of fire blight in Korea in 2015, the occurrence of both pathogens has been independently reported. The co-incidence of these diseases is highly probable given the co-existence of their pathogenic bacteria in the same trees or orchards in a city/district. Hence, this study evaluated whether both diseases occurred in neighboring orchards and whether they occurred together in a single orchard. The competition and virulence of the two pathogens was compared using growth rates in vitro and in planta. Importantly, E amylovora showed significantly higher colony numbers than E. pyrifoliae when they were co-cultured in liquid media and co-inoculated into immature apple fruits and seedlings. In a comparison of the usage of major carbon sources, which are abundant in immature apple fruits and seedlings, E. amylovora also showed better growth rates than E. pyrifoliae. In virulence assays, including motility and a hypersensitive response (HR), E. amylovora demonstrated a larger diameter of travel from the inoculation site than E. pyrifoliae in both swarming and swimming motilities. E. amylovora elicited a HR in tobacco leaves when diluted from 1:1 to 1:16 but E. pyrifoliae does not elicit a HR when diluted at 1:16. Therefore, E. amylovora was concluded to have a greater competitive fitness than E. pyrifoliae.

• The Plant Pathology Journal
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• v.40 no.3
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• pp.290-298
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• 2024

K-Maryblyt has been developed for the effective control of secondary fire blight infections on blossoms and the elimination of primary inoculum sources from cankers and newly emerged shoots early in the season for both apple and pear trees. This model facilitates the precise determination of the blossom infection timing and identification of primary inoculum sources, akin to Maryblyt, predicting flower infections and the appearance of symptoms on various plant parts, including cankers, blossoms, and shoots. Nevertheless, K-Maryblyt has undergone significant improvements: Integration of Phenology Models for both apple and pear trees, Adoption of observed or predicted hourly temperatures for Epiphytic Infection Potential (EIP) calculation, incorporation of adjusted equations resulting in reduced mean error with 10.08 degree-hours (DH) for apple and 9.28 DH for pear, introduction of a relative humidity variable for pear EIP calculation, and adaptation of modified degree-day calculation methods for expected symptoms. Since the transition to a model-based control policy in 2022, the system has disseminated 158,440 messages related to blossom control and symptom prediction to farmers and professional managers in its inaugural year. Furthermore, the system has been refined to include control messages that account for the mechanism of action of pesticides distributed to farmers in specific counties, considering flower opening conditions and weather suitability for spraying. Operating as a pivotal module within the Fire Blight Forecasting Information System (FBcastS), K-Maryblyt plays a crucial role in providing essential fire blight information to farmers, professional managers, and policymakers.

• Research in Plant Disease
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• v.30 no.1
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• pp.82-87
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• 2024

Leatherleaf fern (Rumohra adiantiformis) is an important ornamental plant in Indonesia and global. Green fern leaves with bold dark green color with long shelf-life, attract florists as decoration. Indonesia is one important leatherleaf fern exporters, however currently an outbreak of leaf blight decreased production significantly. Initial symptom was reddish brown spots from edge of leaf, which was gradually followed by dark-brown necrotic lesions causing leaf blight and dried. This is a study to do Koch-Postulate approach and molecular identification, to identify the pathogen of the "new emerging disease" reported. Based on multigene analysis using primers from ITS, β-tub and tef1-α gene markers, the pathogen was identified as Neopestalotiopsis sp. All sequences have been deposited in GenBank with accession number of OR905551 (ITS), OR899817 (ßtubulin) and OR899816 (TEF). This Neopestalotiopsis leaf blight causes an emerging concern in leatherleaf fern in Indonesia and global biosecurity because it infected an export commodity.

• Korean Journal of Medicinal Crop Science
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• v.8 no.2
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• pp.151-156
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• 2000

Field experiments were conducted to investigate the yield and paeoniflorin content between healthy peony and blight plot of top part with every year during 3 years at June, July, August, September, separately. Stem length and diameter, No. of stem in the blight plot of peony were decreased in early in blight time compared with those in no blight growth. No. of flower buds per plant was 5.2, 4.6 in 3 year- grown and 4year-grown plots at late June blight compared with 11.5, 16.2 in no blight. No. of axillary flower was also similar to as above. Main root length and root diameter was most decreased in the plot of late June blight compared with healthy peony. No. of root more than 10mm of root diameter was small in order of blight time, namely Late June, July, August and September. The root dry yield of 4 year healthy peony was most high in 1,603kg per 10a, but it was lowed in 1,007kg in the plot lasted blight during 3years at late June. Paeoniflorin content was no different between 3year-grown and 4year-grown, but it was high in late June blight plot increased with the early in blight time.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.567-570
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• 1998

More than 100 isolates of Stemphylium obtained form leaf blight lesions of garlic (Allium sativum), onion (A. cepa) and leek (A. fistulosum) were identified as Stemphylium vesicarium (Wallr.) Simm. based on various morphological characteristics rather than S. botryosum Wallr. previously reported on those plants in Korea. In controlled inoculations, the pathogen induced the disease symptoms on leaves of garlic 7 days after inoculation. Onion and leek were also artificially infected by the fungus. This is the first report of S. vesicarium causing a leaf blight of garlic, onion and leek in Korea.

• Plant Disease and Agriculture
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• v.1 no.1
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• pp.19-29
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• 1995

A microbial product composed of three antagonistic fungal isolates (Aspergillus sp., Penicillium sp. and Trichoderma sp.) and three bacterial isolates (Arthrobacter sp., Bacillus sp., and Pseudomonas sp.) was tested for the control of Pythium blight caused by Pythium sp., brown patch by Rhizoctonia solani (anastomosis group(AG) 1-1) and large patch by R. solani (AG 2-2) of turfgrasses. Cultures of the antagonistic fungi and bacteria varied in the effectiveness in reducing disease severity of Pytium blight and brown patch on bentgrass. The antagonistic fungal and bacterial isolates were mixed and cultured at 20-$25^{\circ}C$ for 3 days in a growth medium, and the diluted solution of the microbial culture was applied under the field conditions after inoculation of the above turfgrass pathogens. The treated turfgrass was incubated at 28$^{\circ}C$ in a growth chamber. In this experiment, Pythium blight was almost completely controlled and brown patch was slightly decreased by the microbial product, while no control was observed in large patch of zoysiagrass. In zoysiagrass treated with the microbial culture, thatch accumulation was notably reduced.

• Mycobiology
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• v.40 no.4
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• pp.265-267
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• 2012

Sleeping blight was observed on soybean plants grown in Yanggu, Suwon and Geumsan from 2005 to 2011. Symptoms developed on stems and pods of affected soybean plants. Five fungal isolates were obtained from the diseased plants and identified as Septogloeum sojae based on their morphological, cultural and molecular characteristics. Pathogenicity of the fungus was confirmed on soybean plants by artificial inoculation. This is the first report of S. sojae causing sleeping blight in soybean plants in Korea.