• Korean Journal Plant Pathology
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• v.11 no.1
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• pp.90-93
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• 1995

Leaf blotch of Welsh onion was observed at a farmer's field at Kangnung in July 1990. Further collection o the diseased materials was made in 1993 and 1994. The symptom initially appeared as discolored spot and later yellowish blotch with the long axis parallel to the leaf veins, which turned to sooty colored concentric lesion due to heavy production of conidiophores and conidia. Cladosporium allii-cepae (Ranojevic) M. B. Ellis was repeatedly isolated from the leaf lesions. Healthy Welsh onion inoculated with conidial suspension of the fungus produced the typical symptom 10 days after inoculation. Koch's postulates were fulfilled by reisolation of the fungus. This is the first report of a Cladosporium leaf blotch of Welsh onion in Korea.

• The Plant Pathology Journal
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• v.34 no.2
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• pp.93-103
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• 2018

Leaf blotch of wheat caused by Bipolaris sorokiniana is a major constraint to wheat production, causing significant yield reduction resulting in severe economic impact. The present study characterizes to determine and compare pathogenic variability exist/not based on components of leaf blotch disease development and level of aggressiveness due to agroclimatic condition of B. sorokiniana in wheat. A total of 169 virulent isolates of B. sorokiniana isolated from spot blotch infected leaf from different wheat growing agroclimate of Bangladesh. Pathogenic variability was investigated on a susceptible wheat variety 'kanchan' now in Bangladesh. A clear evidence of positive relationship among the components was recorded. From hierarchical cluster analysis five groups were originating among the isolates. It resolved that a large amount of pathogenic diversity exists in Bipolaris sorokiniana. Variation in aggressiveness was found among the isolates from different wheat growing areas. Most virulent isolates BS 24 and BS 33 belonging to High Ganges River Flood Plain agro-climatic zones considered by rice-wheat cropping pattern, hot and humid weather, high land and low organic matter content in soil. Positive relationship was found between pathogenic variability and aggressiveness with agro-climatic condition.

• Research in Plant Disease
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• v.24 no.4
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• pp.249-256
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• 2018

Disease occurrence in apple cultivars on 13-30 apple orchards from April to October 1992-2010 was investigated at 30 days intervals in Gyeongbuk, Gyeongnam and Jeonbuk provinces of Korea. Apple cultivar 'Fuji' was found most susceptible and is being damaged by cedar apple rust, scab, gray mold, Alternaria blotch and Marssonia blotch as major leaf diseases that were observed. The percentage of occurrence of these leaf diseases varies from every year. This variation is based on different rainfall and temperature conditions, cultivation, root stock and changed system of fungicide spray during the particular year and season.

• The Plant Pathology Journal
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• v.26 no.4
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• pp.421-423
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• 2010

New sources of barley (Hordeum vulgare L.) resistant to spot blotch, caused by Cochliobolus sativus, are needed to provide effective resistance because of the rapid change pathotype patterns of C. sativus in fields. The purposes of our study were to develop a method to screen barley for resistance to spot blotch disease and then use this methodology to screen barley genotypes for resistance to the major virulent pathotype Pt4 in barley populations in Syria. A transparent tape method, in which a conidial suspension of C. sativus was dropped onto transparent tape and placed, treated-side down, on the second leaf surface of barley plants. Disease symptoms of fungus were easily detected on the leaves covered by the transparent tape after 48h of inoculation. The transparent tape method was repeatable and the disease scores obtained were correlated (r = 0.91, P = 0.001) with those obtained by the seedling assay. This method may be beneficial in various plant pathology breeding programs.

• Research in Plant Disease
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• v.21 no.4
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• pp.261-267
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• 2015

During the period from 2013 to 2014, disease occurrences by various pathogens in apple cultivars have been investigated in northern Gyeongbuk province of Korea. Anthracnose, white rot, Alternaria leaf spot, Marssonina blotch, and bacterial shoot blight as major diseases have been observed. Pathogens isolated from the symptomatic plants were identified as Colletotrichum gloeosporioides for anthracnose, Botryosphaeria dothidea for white rot, Alternaria alternata for Alternaria leaf spot, Marssonina mali for Marssonina blotch, and Pseudomonas syringae pv. syringae for bacterial shoot blight. Of all diseases, the bacterial shoot blight has been severely increased in chronically infested fields in Gyeongbuk province.

• The Plant Pathology Journal
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• v.39 no.2
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• pp.159-170
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• 2023

Spot blotch disease of wheat caused by Bipolaris sorokiniana (Sacc.) Shoem is considered as an economically important disease which affects all the growing stages of wheat crop. Therefore, it is important to search some effective management strategies against the spot blotch pathogen. Some synthetic elicitor compounds (salicylic acid, isonicotinic acid, and chitosan) and nano-particles (silver and aluminum) were tested against the pathogen to observe the change in biochemical activity and defense action of wheat plant against spot blotch disease. All the tested elicitor compounds and nano-particles showed a significant increase in activity of peroxidase, polyphenol oxidase (PPO), and total phenol over control. The highest increase in activity of peroxidase was recorded at 72 h from chitosan at 2 mM and 96 h from silver nano-particle at 100 ppm. Maximum PPO and total phenol activity were recorded from chitosan at 2 mM and silver nano-particle at 100 ppm as compared to pathogen-treated and healthy control. The lowest percent disease index, lowest no. of spots/leaf, and no. of infected leaves/plant were found in silver nano-particle at 100 ppm and chitosan at 2 mM, respectively. The use of defense inducer compounds results in significantly up-regulated enzymatic activity and reduced spot blotch disease. Therefore, chitosan and silver nano-particle could be used as alternative methods for the management of spot blotch disease.

• Horticultural Science & Technology
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• v.29 no.6
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• pp.531-538
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• 2011

This study was carried out to investigate the influence of defoliation by Marssonina blotch (Diplocarpon mali Harada et Sawamura) on vegetative growth and fruit quality in 'Fuji'/M.9 apple tree. Soluble solid contents decreased when the defoliation percentage by Marssonina blotch was over 10% before the end of September, and fruit weight decreased when percentage of defoliation was over 30%. Fruit red color and starch contents tend to decrease as percentage of defoliation near the fruit increased. Return bloom, fruit weight, and shoot growth the following year tend to decrease as percentage of defoliation increased. Photosynthetic rate of healthy leaves in bourse shoot during the end of September was maintained about $10{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, effects in increasing fruit growth and soluble solid contents after the end of September. Photosynthetic rates for the damaged leaf, damaged area was over 50% on the leaf surface, while 30% of the photosynthetic rates of healthy leaf are without damage applied with Marssonina blotch at the end of September. The results show that the decrease of fruit quality in defoliation treatments may be caused by the decrease of starch contents in fruit, and that was caused by the photosynthetic rates of leaves near fruit was decreased by Marssonina blotch in the wake of August.

• The Korean Journal of Mycology
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• v.46 no.4
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• pp.459-466
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• 2018

In January 2017, discolored black oat seeds were found in the storage depot of a farmhouse in Jeongeup. Pyrenophora sp. was detected in 45% of the oat seeds surveyed. All Pyrenophora isolates obtained from the seeds were identified as Pyrenophora avenae based on the sequences of internal transcribed spacer (ITS) rDNA regions and glyceraldehyde 3-phosphate dehydrogenase (GPDH) gene and validated by morphological and cultural characterization. A phylogenetic tree constructed using the ITS and GPDH sequences showed that the Korean isolates of P. avenae comprise of four genetically distinct groups. Pathogenicity test validated that the fungus is an infectious agent responsible for discolored black seeds and leaf blotch in oat plants. This is the first study report that P. avenae causes leaf blotch disease of oat in Korea.

• Landscaping Tree
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• s.142
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• pp.47-48
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• 2014

칠엽수는 마로니에라는 이름으로 많이 알려져 있는 나무이며, 마로니에는 칠엽수 집안의 나무들을 통틀어서 부르는 이름이다. 일본 원산인 칠엽수, 소아시아 원산이며 열매 겉에 가시가 있는 가시칠엽수는 우리나라의 가로수나 공원수로 많이 심겨져 있다. 이런 칠엽수류에 여름이면 잎에 갈색의 큰 반점이 생기며 지저분해지는 잎마름병이 큰 문제가 되고 있어 이 병을 소개한다. 칠엽수 얼룩무늬병으로도 알려져 있는데 한국식물병리학회의 공식적인 병명은 칠엽수 잎마름병이다.

• Horticultural Science & Technology
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• v.30 no.5
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• pp.579-585
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• 2012

This study was carried out to investigate the effect of potassium silicate on the growth and leaf epidermal characteristics of horticultural crops viz., begonia (Begonia semperflorens Link et Otto) 'Super Olympia Red' and 'Super Olympia Rose' and pansy (Viola ${\times}$ wittrockiana Hort.) 'Matrix White Blotch' and 'Matrix Yellow Blotch' in vitro. Seeds after germination were grown on a quarter strength MS medium supplemented with potassium silicate ($K_2SiO_3$) at 0, 100, 200, or $300mg{\cdot}L^{-1}$ and were maintained under a photoperiod of 16 hours at $25^{\circ}C$. Growth parameters such as plant height, root length, chlorophyll content, fresh, and dry weights have been recorded after a growth period of 58 days for begonia and 94 days for pansy. In begonia, fresh weight was significantly greatest in the $200mg{\cdot}L^{-1}$ $K_2SiO_3$ treatment in both 'Super Olympia Red' and 'Super Olympia Rose'. In both pansy cultivars, fresh weight was the greatest in the $200mg{\cdot}L^{-1}$ $K_2SiO_3$ treatment than other treatments. Chlorophyll content was significantly greater in the $100mg{\cdot}L^{-1}$ $K_2SiO_3$ treatment for both the cultivars of begonia. Leaf area significantly increased with the higher concentrations of $K_2SiO_3$ treatment in both cultivars of pansy. Stomatal structures on the leaf epidermis were observed with scanning electron microscopy (SEM). In begonia 'Super Olympia Rose', the structure of stomata were more compact in size in the $300mg{\cdot}L^{-1}$ $K_2SiO_3$ treatment than in the control. Similarly, in pansy 'Matrix White Blotch' the surface of stomata appeared to be smoother in the $300mg{\cdot}L^{-1}$ $K_2SiO_3$ treatment than those wrinkled appearance in the control. The surface of the leaf epidermis appeared to be compact due to Si deposition, and thus results indicated that Si positively affected the growth and biomass production of these species. Our data show that the effect of Si on growth parameters is strongly dependent on cultivar of the plant species tested.