• Journal of The Korean Society of Grassland and Forage Science
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• v.9 no.3
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• pp.174-178
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• 1989

The investigation was carried out to identify the main pathogen infected with sheath blight in corn plant during 1986-1987. The main fungi of sheath blight isolated from corn plant was identified as Rhizoctonia sobni. Sheath blight in corn plant was first found in early July and infected extremely from late July to end August. Severe sheath blight disease was observed in Gyeongido (Yeoju and Suweon) and Jeonnam (Kwangju) area. The rate of attack was associatied with management and cultural environments of corn plant. Dense planting increased sheath blight, but application of cattle compost reduced the rate of infection. A positive correlation was found between infection rate of shealth blight and concentration of soluble carbohydrate in corn plant (r=0.96). The varieties of Jinjuok, Suweon 83, Suweon 87, Suweon 89, P.3055, P.3160, DK689 and XCG 51 showed remarkable tolerance to sheath blight disease.

• The Plant Pathology Journal
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• v.34 no.3
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• pp.191-198
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• 2018

Fast and accurate diagnosis is needed to eradicate and manage economically important and invasive diseases like fire blight. Loop-mediated isothermal amplification (LAMP) is known as the best on-site diagnostic, because it is fast, highly specific to a target, and less sensitive to inhibitors in samples. In this study, LAMP assay that gives more consistent results for on-site diagnosis of fire blight than the previous developed LAMP assays was developed. Primers for new LAMP assay (named as DS-LAMP) were designed from a histidine-tRNA ligase gene (EAMY_RS32025) of E. amylovora CFBP1430 genome. The DS-LAMP amplified DNA (positive detection) only from genomic DNA of E. amylovora strains, not from either E. pyrifoliae (causing black shoot blight) or from Pseudomonas syringae pv. syringae (causing shoot blight on apple trees). The detection limit of DS-LAMP was 10 cells per LAMP reaction, equivalent to $10^4$ cells per ml of the sample extract. DS-LAMP successfully diagnosed the pathogens on four fire-blight infected apple and pear orchards. In addition, it could distinguish black shoot blight from fire blight. The $B{\ddot{u}}hlmann$-LAMP, developed previously for on-site diagnosis of fire blight, did not give consistent results for specificity to E. amylovora and on-site diagnosis; it gave positive reactions to three strains of E. pyrifoliae and two strains of P. syringae pv. syringae. It also, gave positive reactions to some healthy sample extracts. DS-LAMP, developed in this study, would give more accurate on-site diagnosis of fire blight, especially in the Republic of Korea, where fire blight and black shoot blight coexist.

• The Plant Pathology Journal
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• v.17 no.1
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• pp.40-44
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• 2001

Disease occurrence and development of gray blight of tea (Camellia sinensis) were investigated. Higher incidences and more severe damage by gray blight were found in Japanese tea variety Yabukita than the Korean local variety. In Yabukita, Pestalotiopsis longiseta was more frequently observed on the diseased leaves than P. theae but vice versa in the Korean local variety. This indicates that there was the varietal difference in the distribution of fungal species of gray blight pathogens. Both varieties were most severely damaged during the third harvest period with weather conditions of high temperature and humidity favorable to the disease. Presence of the tea brown blight fungus Glomerella cingulata on the margin of gray blight lesion at the late stahe suggested that the pathogenic fungi of tea gray blight were replaced by the brown blight fungus during the disease development.

• Korean Journal Plant Pathology
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• v.10 no.3
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• pp.245-248
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• 1994

Leaf blight of watermelon severely occurred up to 46% in fields at Hwaseong area in Korea during July, 1993. The causal fungus was identified as Alternaria cucumerina (Ellis et Everh.) Elliott. Pathogenicity tests revealed that all the three watermelon cultivars used were susceptible to leaf blight.

• Korean Journal Plant Pathology
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• v.14 no.4
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• pp.331-338
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• 1998

To develop the model for prediction of potato late blight progress, the relationship between severity index of potato late blight transformed by the logit and Gompit transformation function and cumulative severity value (CSV) processing weather data during growing period in Taegwallyeong alpine area, 1975 to 1992 were examined. When logistic model and Gompertz model were compared by determining goodness of fit for progressive degree of late blight using CSV as independent variable, the coefficients of determination were higher as 0.742 in the logistic model than 0.680 in the Gompertz model. Parameters in logistic model were composed of progressive rate and initial value of logistic model. Initial value was calculated in -3.664. The progressive rate of potato late blight was 0.137 in cv. Superior, 0.136 in cv. Irish Cobbler, and 0.070 in cv. Jopung without fungicide sprays. According to in crease of the number of spray times the progressive rate was lowered, was 0.020 in cv. Superior under the conventional program of fungicide sprays, 10 times sprays during cropping season. Equation of progressive rate, b1=0.0088 ACSV-0.033 (R2=0.976), was written by examining the relationship between the parameters of progressive rate of late blight and the average CSV (ACSV) quantifing weather information. By estimating parameters of logistic function, model able to describe the late blight progress of potato, cv. Superior was formulated in Y=4/(1+39.0·exp((0.0088 ACSV-0.033)·CSV).

• The Plant Pathology Journal
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• v.27 no.2
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• pp.120-127
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• 2011

While many isolates of Alternaria alternata are common saprophytes on trees and shrubs, this study clearly demonstrated that A. alternata is a primary pathogen in lilac (Syringa sp.), causing a leaf-blight that affects different Syringa species. Isolates of Alternaria sp. were collected from leaf blight samples of lilacs in the field. The internal transcribed spacer (ITS) region and morphological characterization were used to identify lilac blight pathogen. Based on 100% ITS nucleotide sequence identities to the Alternaria genus in the GenBank and morphological features, these isolates were identified as A. alternata. Disease symptoms were reproduced in lilac plants inoculated with A. alternata mycelial plugs and sprayed with a fungus-free culture filtrate, indicating that pathogenesis in lilac involves secondary metabolites or toxins. Diagnostic primers were developed to detect Alternaria sp. and A. alternata in lilac leaf blight based on ITS region and four known genes associated with pathogenesis in A. alternata: mixed-linked glucanase precursor, endopolygalacturonase, hsp70, and histone genes. The results from our study indicated A. alternata is a primary pathogen in lilac leaf blight, and these diagnostic primers can be used as a tool for the fast detection of A. alternata associated with lilac leaf blight.

• The Plant Pathology Journal
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• v.37 no.4
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• pp.329-338
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• 2021

Alternaria leaf blight is one of the most common diseases in watermelon worldwide. In Korea, however, the Alternaria species causing the watermelon leaf blight have not been investigated thoroughly. A total of 16 Alternaria isolates was recovered from diseased watermelon leaves with leaf blight symptoms, which were collected from 14 fields in Korea. Analysis of internal transcribed spacer (ITS) region, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and RNA polymerase II second largest subunit (RPB2) were not competent to differentiate the Alternaria isolates. On the contrary, analysis of amplicon size of the histone H3 (HIS3) gene successfully differentiated the isolates into three Alternaria subgroups, and further sequence analysis of them identified three Alternaria spp. Alternaria tenuissima, A. gaisen, and A. alternata. Representative Alternaria isolates from three species induced dark brown leaf spot lesions on detached watermelon leaves, indicating that A. tenuissima, A. gaisen, and A. alternata are all causal agents of Alternaria leaf blight. Our results indicate that the Alternaria species associated watermelon leaf blight in Korea is more complex than reported previously. This is the first report regarding the population structure of Alternaria species causing watermelon leaf blight in Korea.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.12a
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• pp.48-48
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• 2020

Fire blight, caused by Erwinia amylovora(Burrill), is a destructive disease of apple that damages blossoms, shoots, and woody plant organs. The fire blight disease is a worldwide problem for pome fruit growers because all popular apple cultivars are susceptible to the disease. Recently, fire blight of apple rootstocks has become a serious economic problem in high-density orchard systems in korea. The most commonly used dwarfing root stocks, M.9 and M.26, are highly susceptible to E. amylovora. The objective of the apple rootstock-breeding program has been to develop pomologically excellent rootstocks with resistance to abiotic and biotic stresses, including fire blight. Budagovsky 9 (B.9) apple rootstock is reported to be highly susceptible when inoculated with E. amylovora, although results from multiple trials showed that B.9 is resistant to rootstock blight infection in field plantings. So we tried to collect the apple rootstocks traits of fire blight resistance. The apple genotype Malus Robusta 5 (MR5) represents an ideal donor for fire blight resistance because it was described as resistant to all currently known European strains of the pathogen. The PCR for detecting the MR5 gene using the primers Md_MR5_FL_F/Md_MR5_FL_R. The results of these experiments confirmed some apple rootstocks traits of fire blight resistance showed the MR5. Furthermore, this gene is confirmed to be the resistance determinant of Mr5 as the transformed lines undergo the same gene-for-gene interaction in the host-pathogen relationship MR5-E. amylovora.

• Korean Journal Plant Pathology
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• v.12 no.2
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• pp.237-244
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• 1996

길항곰팡이 3종(Aspergillus sp. A101, Penicillium sp. B202, Trichoderma sp. C303), 길항세균 3종(Arthrobacter sp. AN303)또는 이들 모두의 혼합균주를 배양하여 creeping bentgrass 양묘장에 처리하여 Pythium blight, brown patch 및 dollar spot의 방제효과를 조사하였다. 또한 길항미생물 6종의 배양액을 살균제와 병용하여 그린에 살포하여 이들 토양병에 대한 방제효과를 조사하였다. 양묘장에서는 미생물의 종류에 관계없이 Pythium blight 억제효과가 커 3회 이상 미생물제 처리시 병이 전혀 발생하지 않았다. 그러나 brown patch와 dollar spot은 미생물제에 의한 방제효과가 크지 않았으며, 살균제에 의해 효과적으로 방제되었다. 미생물제와 살균(Pythium blight 방제용 살균제 제외)를 병용하여 처리한 그린에서는 살균제 단독처리와 비교할 때 brown patch는 유의적으로 억제되었고 Pythium blight와 dollar spot은 차이가 없었다.

• Korean Journal of Medicinal Crop Science
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• v.21 no.5
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• pp.388-393
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• 2013

This study was conducted to select environmental friendly organic materials for controlling the ginseng alternaria blight and to evaluate their effects from 2011 to 2012. Alternaria blight is caused by Alternaria panax and is the most common ginseng disease in Korea. Environmental friendly organic materials were used to reduce amount of chemical fungicides and the number of spray for control of Ginseng Alternaria leaf blight. In 4 years of ginseng, control value of Alternaria leaf blight by single application of Defenoconazole WP was 82.3% and those of single application was 62.0~75.9%. Consequently, mixed or alternated application of eco-material products could be recommended as a control method to reduce the amount of fungicides.