• The Plant Pathology Journal
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• v.27 no.1
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• pp.14-19
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• 2011

Early blight of potato, caused by Alternaria solani, is a ubiquitous disease in many countries around the world. Our previous screening of several Iranian potato cultivars found that significant variation in resistance phenotypes exists between two cultivars: resistant 'Diamond' and susceptible 'Granula'. Our previous analysis of five different pathogen isolates also identified varying degrees of aggressiveness regardless of the host cultivar. Here, a bioassay was used to study the role of liquid culture exudates produced in vitro on pathogenicity and elicitation of disease symptomology in seedlings as well as detached leaves. Responses of host genotypes to the exudates of the two A. solani isolates were significantly different. Detached leaves of the resistant cultivar 'Diamond' elicited fewer symptoms to each isolate when compared to the susceptible cultivar 'Granula'. Interestingly, the phytotoxicity effect of the culture filtrate from the more aggressive isolate A was higher than from isolate N suggesting an increased concentration or strength of the toxins produced. Our results are significant because they indicate a correlation between symptoms elicited by A. solani phytotoxins and their aggressiveness on the host.

• Research in Plant Disease
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• v.26 no.4
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• pp.239-249
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• 2020

To find out the cause of the fire blight outbreak in apples and pears of Korea in 2019, we investigated disease appearing situation of thirty fire blight infected orchards, and interviewed farmers to determine the cultivation characteristics. Fire blight occurred mostly in orchards that had infected more than 2 years before. The cause of this were as follows: farmers did not know the symptoms of the disease properly. It is presumed that it has spread from the first occurrence to the surrounding orchards by flower-visiting insects or farmers and to a short distance or a long distance by the same cultivator or co-farmer. These series of processes repeated in the newly spreading area, and then disease reports increased as farmers became aware of fire blight. To minimize the spread of fire blight in Korea, it suggested that thorough education of farmers for early diagnosis and quantitative detection technology that can diagnose even in no symptom showing plants. And chemical or biological spraying systems suitable for domestic cultivation methods, which are producing large fruits, and molecular epidemiological studies of pathogens.

• Journal of Life Science
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• v.8 no.3
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• pp.294-297
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• 1998

The objective of this study was to establish the stable cultivating method of adlay in paddy fields. The effect of soil moisture on the early of the transplanted adlay seeding was evaluated in 1996. the suitable transplanting period and the relationship between water management and leaf blight disease were tested in 1997. The critical transplanting date was June 30. rooting of transplanted adlay plants was retarded when soil moisture was saturated. However, sufficient soil moisture since one month after transplanting was required for the control of leaf blight disease and high yield of adlay.

• Journal of Ginseng Research
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• v.15 no.1
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• pp.21-30
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• 1991

This study was conducted to know the elects of light intensity of polyethylene net shading on the growth status, photosynthesis and root yield of ginseng plants. Polyethylene net shading of loft transmittance was the best one among light intensities of polyethylene net used in view of photosynthesis and decreasing of early leaf defoliation. According to increase of light intensity under the shading chlorophyll contents of ginseng leaves were decreased. As it was increased over 2 mg/g Photosynthesis and total saponin of leaves showed on the decrease remarkably. The rate of alternaria blight of ginseng plants showed the positive correlation between light intensity and leaking rate. The shading of 10% transmittance in root yield was increased by 40% in 6-year-old ginseng plant as compared with common straw shading, due to decreased missing plant and increased root weight.

• Research in Plant Disease
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• v.9 no.4
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• pp.209-212
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• 2003

Blister blight was occurred on tea (Thea sinensis) in a farmer's tea garden located in Sicheon-myon, Sancheong-gun, Gyeongnam province, Korea. The typical symptoms of the disease were appeared on the leaves and bud. The early symptom were started with small yellowish spots then infected area became upheave and covered with white blister which the hymenium de.veloped from under neath of epidermis. Generally, the infected leaves and buds were appeared like rice cake. Colonies formed on PDA were developed white, later turned milk white. Basidia were 2 sterigma, and 30${\sim}$53 ${\times}$ 3.1${\sim}$5.8 ${\mu}m$ in size. Basidiospores were ellipsoid curved, coloriess, 1-celled and 11${\sim}$14.7 ${\times}$ 4${\sim}$5.4 ${\mu}m$ in size. The optimum temperature for growth of the fungus was about $25^{\circ}C$ on PDA and PSA. This is the first report on the blister blight of tea caused by Exobasidium vexans in Korea.

• Korean Journal of Agricultural Science
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• v.3 no.1
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• pp.23-30
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• 1976

This study was done to find out the effect of seeding seasons of rice varieties on the occurence of sheath blight caused by Corticium sasakii. The results obtained are summarized as follows; 1. The percentage of infected stems and susceptibilities to sheath blight wered ecreased as the transplanting dates were delayed. 2. The susceptibilities to sheath blight of early maturing varieties were high, medium maturing varieties were intermediate and late maturing varieties were least. 3. The percentages of infected stems of Indica X Japonica varieties checked on 28th July were lower than those of Japonica varieties, but the susceptibilities were not significant between them. 4. At all varieties, highly significant correlation was recognized between the susceptibilities and the heading dates. Also relatively high correlation was appeared between the susceptibilities and the accumulated temperatures from 10 days before heading date to 30 days after it. This indicates that the susceptibility was much influenced by high temperature of the latter part of the rice plants growth.

• Korean journal of applied entomology
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• v.21 no.4 s.53
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• pp.216-221
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• 1982

This experiment was conducted in Jeonnam to investigate the effects of fertilizer amounts at two application levels on disease severity of bacterial leaf blight, yield and qualify of rice grains using nineteen rice cultivars. Incidence of bacterial leaf blight was more severe in the field with higher amount of fertilizer application. Disease severity was also different depending upon maturity of rice cultivars of early maturing group, however, the flag, second and third leaves were diseased in rice cultivars of medium late maturing group. Such differences were more obvious in the field with higher amount of fertilizer application than in the field with ordinary fertilizer application. Rice cultivars such as Taebaegbyeo, Hangangchalbyeo, Baegunchalbyeo, Palgwangbyeo and Milyang 42 were resistant whereas rice cultivars such as Milyang 30, Geumgangbyeo, Nagdongbyeo and Jinjubyeo were susceptible to bacterial leaf blight in both treatments. However, fertilization rate and percentage of ripeness were decreased resulting in heavy loss of yield. The rate of green-kerneled rice was increased resulting in poor qualify.

• Korean Journal of Medicinal Crop Science
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• v.5 no.3
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• pp.206-210
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• 1997

The pathogenic fungi associated with blight of leaf and stem in peony were leaf spot (Alternaria sp.), powdery mildew (Erysiphe aquilegiae) and rust (Cronartium flaccidum). The infection of leaf spot and powdery mildew begins from late April to midMay and rust was infected in early June. Blight time of aerial part in peony started from late May and the ratio of blight on leaf and stem was more than 50% in late Aug. Yields of root by the incidence time of blight of leaf and stem were 69.1% in late June, 65.4% in late July and $87.6{\sim}92.7$% in August and September. The number of root of more than 10mm in root diameter blighted in late June and July was much lower than in August, but the paeoniflorin content in the former was much higher than the latter.

• Korean Journal of Medicinal Crop Science
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• v.23 no.4
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• pp.284-291
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• 2015

This study was performed to investigate the effects of enhanced light transmission on plant growth, photosynthetic ability, and disease tolerance to leaf blight, anthracnose in ginseng (Panax ginseng C. A. Meyer, Araliacease family) during the early growth stage (April to June). The photosynthetic ratio, stomatal conductance, and stem diameter of plants grown under a shade net with 15% light transmission rate showed an increasing trend compared to the control plants (5% light transmission rate) although the growth of the aerial parts were not influenced significantly. Plant height, stem length, and leaf length of treated plants were not significantly different from those of the control plants. Root parameters, such as root length, diameter, and weight of treated plants increased significantly compared to the control. Yield performance ($187.4kg{\cdot}10a^{-1}$) of treated plants was 55.5% higher than that of the control ($150.4kg{\cdot}10a^{-1}$). Additionally, disease severity scores of treated plants were lower than those of the control plants, revealing higher survival rates. To retain high yield potential and enhance the level of disease tolerance in ginseng, we suggest the increase of light transmission rate during the early growth stage.

• Korean journal of applied entomology
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• v.18 no.1 s.38
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• pp.55-61
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• 1979

Since rice high yielding practices with blast resistant varieties induced severe and earlier infestation of sheath blight recently, it is strongly suggested to spray at least 10 days earlier than the present recommendation and more than 2 sprays from early July to early August seems to be essential for the efficient control of sheath blight in the future. Among organo-arsenic fungicides, MAFe (Neo Asozin) is known as the most effective and economic as well as with the advantages of free phytotoxicity and safe residure on rice, and applications of the mixed formulation with other fungicide and insecticide is suitable for the one-hit control of rice diseases and insect pests in connection with cooperative mass control system. Present level of arsenic $(As_2O_3)$ residue in .ice is summarized as 0.2ppm to 0.65 ppm in highest average, and there are more possibilities of extensive MAFe fungicide uses for the efficient and economic control of this disease. During the past few years, the acreage of sheath blight control has been extended several times while the increase of the fungicides used for sheath blight showing about 10 times in quantity and mort than 15 times in amount, and also the fungicide cost estimated for the control is differ from 1 to 12 billion 1on by the use of MAFe or antibiotic fungicide in a year.