• The Plant Pathology Journal
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• v.40 no.2
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• pp.225-232
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• 2024

The microbiomes of two important rice cultivars in Vietnam which differ by their susceptibility to the bacterial leaf blight (BLB) disease were analyzed through 16S rRNA amplicon technology. A higher number of operational taxonomic units and alpha-diversity indices were shown in the BLB-resistant LA cultivar than in the BLB-susceptible TB cultivar. The BLB pathogen Xanthomonas was scantly found (0.003%) in the LA cultivar, whereas was in a significantly higher ratio in the TB cultivar (1.82%), reflecting the susceptibility to BLB of these cultivars. Of special interest was the genus Acholeplasma presented in the BLB-resistant LA cultivar at a high relative abundance (22.32%), however, was minor in the BLB-sensitive TB cultivar (0.09%), raising a question about its roles in controlling the Xanthomonas low in the LA cultivar. It is proposed that Acholeplasma once entered the host plant would hamper other phytopathogens, i.e. Xanthomonas, by yet unknown mechanisms, of which the triggering of the host plants to produce secondary metabolites against pathogens could be a testable hypothesis.

• Research in Plant Disease
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• v.21 no.4
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• pp.268-272
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• 2015

Bacterial leaf blight caused by Pseudomonas syringae pv. porri is one of the major bacterial diseases of garlic (Allium sativum). In South Korea, the disease has only been observed in garlic-growing regions of Jeju island. The spatial distribution pattern of the disease was analyzed by binary power law, in which the natural logarithm of the observed variance is regressed on the natural logarithm of the binomial variance. The estimated slope (b=1.361) of the regression was greater than 1 which meant that the diseased plants were aggregated. The sequential sampling plans were developed for estimating the mean incidence rate ($p_m$) and classifying the mean incidence as being below or above the critical incidence rate ($p_t$). These results could be used on more efficient and higher precisive sampling for bacterial blight of garlic compared to fixed sample sized sampling.

• Research in Plant Disease
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• v.9 no.4
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• pp.213-216
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• 2003

A bacterial disease of tea plants(Camellia sinensis L.) was found in the graftage nursery grown under vinyl house conditions in Suncheon city, Korea, in spring of 2002. The primary symptoms of the disease include small, water-soaked and dark brown spot development on the young leaves. This spot gradually increases in size, especially taking on elongate shape along the midrib or vein of the leaf, and then turns black. The diseased leaves were defoliated easily. Ten strains were isolated from the infected leaf. Inoculation on tea leaf with these isolates produced the same symptoms of naturally infected plants. On the basis of stain reactions, morphological characterization, colony pattern, physiological and biochemical reactions, the bacterium was identified as Pseudomonas syringae pv. theae. This is the first report of brown blight of tea plant in Korea.

• Korean journal of applied entomology
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• v.19 no.1 s.42
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• pp.51-55
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• 1980

The study has been carried to confirm pathogenesity among the isolates which obtained from leaf blight type symptoms and Kresek type symptoms, and also to observe varietal resistance among 29 varieties and/or lines through the introduction of two different pathotypes, of Xanthomonas oryzae, by the use of root clipping and pin prick methods. There was no significant differences among the isolates when their growth in plant tissue were compared. There was certain tendency, however, that the isolates from Kreseked plants showed longer lesion than those from blight type lesions. Both isolates from blight type and Kresek type induced the same degree of Kresek syptoms when they were introduced into plants by root cutting in the suspension prior to transplant. Varietal resistance to 'Kresek' appeared to be the same with those on leaf blight type though Wase Aikoku group varieties showed Kresek symptoms which is not the case with leaf blight type. IR 20 in Kogyoku group varieties showed highly resistant reaction to Kresek type. Root clipping method induced the more of Kresek than those by pin pricking method.

• 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 Plant Resources
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• v.10 no.2
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• pp.128-134
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• 1997

This study was conducted to test on the resistance of varieties bred by crossing with Asominori to bacterial leaf blight. Nakdongbyeo and Dongjinbyeo which were susceptible to HB 9011, 8 resistant varieties including Ilmibyeo derived from Asominori and Asominori, Hwangok, 13 varieties including Chukoku 45 which were resistance to HB 9011, HB 9022 and HB 9033 were used to screen their res ponce depending on the various screening methods such as the true resistance, the secondary infection resistance and the disease common field test methods, and the results are as follows: Among 13 varieties tested, 11 varieties including llmibyeo showed tme resistance to HB 9011. Less than 1.0cm of disease lesion were developed on these varieties. Disease lesion was not developed on most of the Asominori lines including Daechongbyeo against IIB9011 and 1lmibyeo was also resistance to HB 9011, on this variety disease lesion area rate was 1.2%, and 7 varieties including Hwajinbyeo showed field resistance to HB 9022. Disease lesion area rate were 19.6% on Nakdongbyeo. 15.6% on Dongjinbyeo, from 3.0% to 2.4% on Asominori lines, and 0.5% on the Asominori when screened at disease common area. Disease was not developed on Keumnambyeo. Significant correlation coefficiences were found between the results from the test methods of the true resistance, the field resistance ancl the field resistance at disease common field tests on Asominori lines, but in some cases, even the varieties on which disease lesions developed, showed field resistance to HB 9022 and HB 9033.

• The Plant Pathology Journal
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• v.24 no.2
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• pp.171-177
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• 2008

In this study, we investigated the induced defense response and protective effects against Stemphylium vesicarium by application of benzothiadiazole ($Bion^{(R)}$) and di-potassium phosphate salt $(K_2HPO_4)$ to onion. Onion leaves were sprayed with $Bion^{(R)}$ and $K_2HPO_4$, then inoculated 2 days later with a virulent strain of S. vesicarium under greenhouse conditions. Disease severity and activities of peroxidase (PO), polyphenoloxidase, phenylalanine ammonia-lyase (PAL) and phenol contents were evaluated in the treated leaf tissues. Reduction in the disease severity was observed in plants treated with $Bion^{(R)}$ and $K_2HPO_4$. Onion plants treated with $Bion^{(R)}$ and $K_2HPO_4$ and inoculated with the pathogen showed significantly higher PAL activity, PO activity, and phenol contents than inoculated water-treated plants 2 days after the treatment. In conclusion, the results of this study provide evidence that application of simple non-toxic chemical solutions as di-potassium phosphate and $Bion^{(R)}$ can control Stemphylium leaf blight of onion.

• Journal of Sericultural and Entomological Science
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• v.37 no.1
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• pp.86-91
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• 1995

Isolation and pathogenicity of Fusarium spp. from mulberry shoot rot and severity of diseases which were known as bacterial blight were examined on four mulberry varieties in Suwon, Kongju and Chuncheon, A symptom of mulberry shoot rot was initiated long brown spot on young leaves and shoots. It was developed into dark brown spot and produced white mycelia and spores on the diseased symptoms. A symptom of bacterial blight showed leaf rolling and water soaking spot and produced bacterial ooze on leaf and shoot However later stage of upper two types of symptom was hardly distinguished. Severities of shoot rot and bacterial blight were 7.5% and 4.4% in Suwon, respectively. Isolation of Fusarium spp. on shoot rot symptoms was highter than that on bacterial blight symptoms, but isolation of Pseudomonas spp. was higher on bacterial blight symptoms. Trends of pathogenicity of Fusarium spp. and Pseudomonas spp. were similar to inoculation works, and isolations of pathogenic Fusarium spp. from center of symptom was higher than that from 30cm of symptom of all samples in three cultivation areas. Disease severities of shoot rot on variety of Kaeryangppong were 13.9%, 15.9% and 17.2% in Suwon, Kongju and Chuncheon, respectively. However variety of Cheongolppong was highly resistant to shoot rot disease in three cultivation areas.

• 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.

• Mycobiology
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• v.46 no.3
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• pp.278-282
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• 2018

Chrysanthemum coronarium is an economically important plant in Asia, and used medicinally, ornamentally and as a vegetable. In April 2017, leaf spot disease on C. coronarium was observed in Shiyan, Hubei, China. A single-spore isolate was obtained and identified based on morphology and sequence analysis using four regions (rDNA ITS, GAPDH, $EF-1{\alpha}$, and RPB2). The results indicated that the fungus is Alternaria argyranthemi. The pathogenicity tests revealed that the species could cause severe leaf spot and blight disease on the host. This is the first report of leaf spot disease on C. coronarium caused by A. argyranthemi in the world, which is also a new record of Alternaria species in China.