• Korean journal of applied entomology
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• v.23 no.1 s.58
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• pp.15-21
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• 1984

The virus infecting French bean (Phaseolus vulgaris L.) was identified as Bean Common Mosaic Virus(BCMV) based on the host range, symptomatology, serology, morphology of virus particles and inclusion bodies. Isolates of BCMV were obtained from seeds of P. vulgaris collected at Suweon, Jangsu and Jinju in Korea. French bean produced vein clearing, mosaic, stunting and leaf curling. Symptom of Chenopodium quinoa was local lesions on the inoculated leaves, not on the upper leaves. The electron micrograph of the virus from French bean was flexuous approximately 750nm in length. Cylindrical and pinwheel cytoplasmic inclusion bodies were observed in French bean leaf infected by BCMV. BCMV from the French bean was transmitted through seed and green peach aphid, Myzus persicae. The thermal inactivation point was $55\~60^{\circ}C$, dilution end point was $10^{-3}\~10^{-5}$ and longevity in vitro was $2\~3$ days for BCMV from French bean. The isolates of BCMV reacted positively against BCMV antiserum. The extract of BCMV infected bean leaves, Azukibean mosaic virus (AZMV) and Cowpea aphid borne mosaic virus(CaMV) also reacted with BCMV antiserum, however, BCMV and CaMV showed the spur in agar gel diffusion test.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.4
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• pp.246-253
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• 2012

Despite frequent freezing injury to tea trees due low temperature, drought, and strong wind during wintertime, no comprehensive measurements have been taken. We selected and examined 9 locations in Hwagae-myeon and 4 places in Agyang-myeon, Hadong-gun, Gyeonsanggnam-do where low temperature damage had occurred between December 2010 and February 2011. Our objective is to examine the effect of frost damage on the morphological symptom and harvest of a tea tree exposed to a constant low temperature environment during wintertime. The results of our analyses on meteorological environment, tea leaf chromaticity, water content and trypan blue are as follows: (1) the number of days with temperature of $-10^{\circ}C$ or less, which were subject to frost damage to a tea tree were 8 and 13.6% during the winterization period in 2011; (2) the accumulated time was 1,308 minutes, and the longest duration at $-10^{\circ}C$ was 588 minutes from 21:08 p.m. 15 January to 7:30 a.m. $16^{th}$ January. The rainfall was only 104 mm which was 306 mm less than the previous year; (3) the lightness L values in 2011 were higher than in 2012 due to dehydration and necrosis by blue discoloration and red discoloration at all areas in chromaticity measurement; (4) the water content in a tea leaf in 2011 was higher than in 2012 due to low rainfall and strong wind, and almost no cell death phenomenon was observed from normal tea leaves subject to no low temperature stress in a trypan blue analysis; and (5) partial coloration due to cell death, however, took place in the leaves damaged by blue discoloration subject to low temperature stress, and most coloration due to cell death took place in the leaves damaged by red discoloration.

• Korean journal of applied entomology
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• v.21 no.3 s.52
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• pp.113-122
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• 1982

Appressorial formation of Pyricularia oryzae on leaves showed no marked difference between highly resistant Tongil and susceptible Norm No. 6. Race N-2 of the blast fungus penetrated directly into motor cells of susceptible cultivar Norm No. 6, later extensively spreading hyphae were developed, while in the cultivar Tongil, after penetration, no further hyphal extension resulted. In discoloration of infected tissues, the highly resistant cultivar Tongil not only discolored rapidly, but also the percentage of discolored cells was higher than the susceptible cultivars, Jinheung and Norm No. 6. The respiratory rate, was generally higher in infected tissue than in healthy tissue. No significant difference in the respiration rate of resistant Suwon No. 180 was not found between the infected and healthy leaf tissue, whereas, in susceptible Jinheung, a marked increase in respiratory rate was caused by blast infection. The respiratory rate increased at the appearance of the first visible symptom in all cultivars resistant or susceptible. Higher peroxidase activity was found in infected tissues as compared with healthy tissue. Peroxidase activity increased in resistant and susceptible reactions. Particularly, in resistant reaction, the increase of the activity was more pronounced. In highly resistant reaction, there was no difference in peroxidase activity between healthy and infected tissues. Ascorbic acid oxidase, hydroquinone oxidase and catechol oxidase had the same trend as the peroxidase. In contrast, activity of catalase rather decreased in leaf tissues infected with compatible races of the fungus.

• Asian Journal of Turfgrass Science
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• v.24 no.1
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• pp.9-15
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• 2010

During 2008~2009 winter season, yellow patch and gray snow mold occurred on turfgrass plants in golf courses in Kangwon and Jeonbuk provinces, respectively. The fungi associated with the diseases were identified as Rhizoctonia cerealis Van der Hoeven and Typhlua incarnata Lasch ex Fr., based on the morphological characteristics of hyphae and sclerotia. R. cerealis and T. incarnata were pathogenic to most turfgrass and crop species tested. R. cerealis infected crown, stem and leaf tissue of the host plants, and the symptom was light yellow circular patch. Individual infected leaf near the margin of patch developed red color first and finally turn brown. The symptoms caused by gray snow mold pathogen are water-soaked spots, and became a watery soft rot. Infection parts became yellow and then turned brown followed by death of the whole plant. White mycelia were developed on higher petioles, leaves, and on soil where these plant parts lay, and black sclerotia of variable size and shape formed in the mycelial mass. All isolates tested were pathogenic on most turfgrass and crop plants, and significantly different in aggressiveness. Disease severity increased with longer snow cover days on target plants, suggesting that disease severity was expressed over snow cover days. There were significant differences in disease severity among the graminious species, and among cultivars within each species, indicating varying levels of susceptibility to R. cerealis and T. incarnata.

• Korean Journal of Medicinal Crop Science
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• v.17 no.6
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• pp.439-444
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• 2009

This study was to set the guidelines of soil chemical components in order to assure the safety and quality of the panax ginseng from physiological disorder. The disorder symptoms appeared on the leaf with yellow spot, atrophy, yellow-brown spot, also showed red skin and rough skin of the root. Occurrence type of physiological disorder in cultivated field divided into two types : type I 'such as, yellow spot' consist of single disorder symptom; type II 'such as, yellow spot and yellow-brown spot' consist of two or more different disorder symptoms. The individual contribution of soil properties to the occurrence type was as follows ; The yellow spot was affected by Na > $NO_3$-N > salinity (EC) in soil. The same results was observed in red skin. Atrophy was affected by $NO_3$-N > salinity (EC) > Ca > Mg. Rough skin was affected by $P_2O_5$>pH>Organic material > K. It showed positive associated to $P_2O_5$, pH and K, but negative associated to organic matter. Simultaneous occurrence of two different disorder, including cases which yellow spot and yellow-brown spot, those were affected by $NO_3$-N > salinity (EC) > Na > Mg. In the case of atrophy plus yellow-brown spot, those also were affected by in the order : $NO_3$-N > salinity (EC) > Ca > Mg > Na. Red-rough skin was affected in the order : salinity (EC) > $NO_3$-N > K > Na. Soil chemical components appear to be related to occurrence of physiological disorder, particularly in salinity (EC) and $NO_3$-N. The salinity (EC) and $NO_3$-N were negative related to plant growth. In addition, exchangeable cation capacity play critical roles in attributing to complex occurrence of physiological disorder.

• Research in Plant Disease
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• v.28 no.2
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• pp.82-91
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• 2022

Recently, several in vitro studies have reported antiviral activity of agents of systemic acquired resistance against plant virus infection, but the approach has not been applied in a wide range of agricultural fields. The objective of this study was to evaluate the inhibitory effect of the exogenous application of salicylic acid (SA), chitosan (CH), or eugenol (EG) in tomato yellow leaf curl virus (TYLCV) infection of greenhouse-grown tomato plants. In vitro, the initial time of symptom was observed in TYLCV-infected plants (VP) of the resistant cultivar 'Superdotaerang' at 12 days post inoculation (dpi) after application of antiviral agents. At 32 dpi, the disease rate of TYLCV in the CHT+VP (0.1% chitosan and virus infected control) treated plants was 87.5%, lower than that of the other treatment. However, the virus content in the CHT+VP treated plants was higher than those of the other treatments, and SA, EG, and CH did not show significant effect on plant height or shoot and root fresh weight. Our results from summer-cultivated greenhouse-grown tomatoes show that none of the tested agents had an inhibitory activity on viral infection or yield of tomato 'Dotaerangsola'cultivar. In contrast, all treated 'TY Giants' cultivars that possessed TYLCV resistance genes Ty-1 and Ty-3a did not show typical symptoms and the virus content was remarkably lower than those in the TYLCV treated plants in 'Superdotaerang'. The results of this research indicated that the planting of resistant tomato cultivars was effective method instead of using SA, EG, and CH (known as resistance-inducing factors for control) of TYLCV in the field.

• Journal of Bio-Environment Control
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• v.8 no.2
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• pp.115-124
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• 1999

This study was conducted to determine the optimum root zone environment condition and proper nutrient management system for lettuce in hydroponics. For the root zone environment condition, several level of pH and electrical conductivity (EC) were treated respectively. Though all the level of pH 4 to pH 8, except pH 3, performed better growth without any visible physiological disorder, the optimum pH of the nutrient solution for lettuce production was pH 5.5 to 6.0. The optimum ionic strength of the solution was EC 1.2 to 1.6 mS $cm^{-1}$ / because higher nutrient level caused tip burn symptom by calcium deficiency. Considering the above results, it is concluded that lettuce can be efficiently mass-produced through the optimum root zone environment.

• Journal of Dental Rehabilitation and Applied Science
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• v.17 no.4
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• pp.275-282
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• 2001

Centric relation is defined the horizontal position between maxilla and mandible when condylar head of mandible is positioned adequately in mandibular fossa. The most recent concept of centric relation position is defined as the mandibular position in which the condyles are in their most superoanterior position in the articular fossa, resting against the posterior slope of the articular eminences, with the articular disk properly interposed. To be suitable as a reference point during occlusal management, a mandibular position of centric relation has to be functionally acceptable to the patient and clinically reproducible and achievable during everyday practice. There are numerous methods for determination of centric relation, and in this study we used three of them, Gothic arch tracing(Group I), leaf gauge(Group II), and anterior jig(Group III). The subjects were 10, 8 men and 2 women, age-ranged from 23 to 26 years old, had no prosthetics in thier mouth, and had no sign and symptom of temporomandibular disorders. We gained three occlusal records using each method, and then the degree of the reproducibility was examined with split cast technique. In this study the reproducibility of centric relation using split cast technique was greater in the order of Group I(mean 1.6), Group II(mean 1.4), and Group III(mean 1.3), but there was no significant differences among them statistically(p>0.05).

• Research in Plant Disease
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• v.10 no.4
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• pp.279-284
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• 2004

A rust fungus has caused a serious early defoliation of Zanthoxylum schinifolium during growing seasons every year at the plantations located at Hadong and Jinju, Kyeongsangnam-Do in Korea. In order to identify the rust fungus and clarify its life cycle in Korea, aeciospores from Pinus thunbergii were artificially inoculated on the leaves of Z. schinifolium. Uredinial stage was successively formed on the leaves of Z. schinifolium. Based on the artificial inoculation test and on the morphological features of the dried specimens collected from P. thunbergii and Z. schinifolium, this rust fungus was identified as Coleosporium xanthoxyli. Morphological features of aecial and uredinial stages of the species were described. The first symptom of the infection was developed from later June to early July. And leaf infection ratio was 17.8%-58.7% during August at Hadong and Jinju regions of Kyeongsangnam-Do in Korea.

• The Plant Pathology Journal
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• v.27 no.4
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• pp.372-377
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• 2011

A virus causing mottle and stunt symptom on Zea mays was observed around Ulleng-do, Korea and identified as Cucumber mosaic virus (CMV-ZM) based upon biological, serological, and molecular characteristics. In host range studies, the CMV-ZM isolate produced local lesions on Datura stramonium, Vigna unguiculata, Cucurbita moschata, Chenopodium amaranticolor, Ch. quinoa, whereas this isolate produced systemic mosaic on Nicotiana tabacum cv. 'Xanthi-nc', Capsicum annuum, Solanum lycopersicum, Solanum melongena, Cucurbita pepo, and Z. mays. In addition, chlorotic local rings on inoculated leaves along with severe mosaic, malformation, and fern leaf symptoms on upper systemic leaves were shown in N. glutinosa plants. Complete nucleotide sequences of each genomic RNA segment was determined and compared to those of the other CMV strains. Comparison of the nucleotide sequence of 1a open reading frame (ORF) revealed approximately 89.2-92.4% sequence identity with each CMV subgroup IA and IB strain, while showing only 78% sequence identity with CMV subgroup II. Nucleotide sequence analysis of RNA2 ORFs revealed 85.3-97.6% sequence identity with subgroup I. In ORFs of RNA3, levels of nucleotide sequence identities were higher than 92-99.2% with CMV subgroup I and lower than 82% with CMV isolates of subgroup II. These results suggest that CMV-ZM isolate is more closely related to subgroup I than subgroup II and therefore, CMV-ZM isolate might be classified into as CMV subgroup I based on biological and molecular analysis.