• Korean Journal Plant Pathology
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• v.14 no.4
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• pp.319-324
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• 1998

Induction of systemic acquired resistance (SAR) against phytophthora blight and pathogenesis-related (PR) protein accumulation by TMV infection in pepper plant (Capsicum annuum cv. Nockwang) were examined to understand the mechanism of the systemic acquired resistance in pepper plant. The zoospore suspension of Phytophthora capsici was inoculated on stem of pepper plant in which TMV-pepper strain had been inoculated on fully expanded upper leaves, and thephytopha blight incidence was examined. Both disease severity and lesion length of phytophthora blight were much smaller in TMV pre-inoculated pepper plant than in uninoculated control plants. The phytophthora blight incidence was decreased about 50% in the TMV pre-inoculated pepper, compared to the uninoculated control plant at 10 days after P. capsici inoculation. Accumulation of PR1 and PR5 proteins in intercellular fluid of TMV-inoculated and uninoculated upper leaves were monitored by immuno-blot with tobacco P1b and PR5a, antibody during induction of SAR. PR1 and PR5 were detected from 24 hours after TMV inoculation in both TMV-inoculated and uninouclated upper leaves, and increased rapidly in TMV-inoculation in uninoculated upper leaves were defoliated. PR5 could be detected upto 20 days after TMV inoculation in uninoculated upper leaves. These results suggest that TMV infection induces SAR against phytophthora blight in pepper plant, and that PR proteins are accumulated very rapidly during induction of SAR and maintained for quite long time in pepper plant.

• Research in Plant Disease
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• v.17 no.3
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• pp.402-404
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• 2011

The Sclerotium blight was found on Phalaenopsis spp. at Dong-du-cheon city, and Hwa-seong city, Gyenggido, Korea in September 2009. The symptom included yellowing on lower leaves and wilt of a whole plant. Severely infected plants were blighted and died eventually. White mycelial mats appeared on the surface of basal stem and bulbs and the sclerotia were formed on stems, roots, and sphagnum moss. The sclerotia were spherical, 1-3 mm and white to brown. The optimum temperature for the growth and sclerotia formation was $25-30^{\circ}C$ on PDA. On the pathogenicity test, the first symptom appeared 5 days after inoculation and developed to severe stem rot and blight. On the basis of mycological characteristics and pathogenicity, the causal fungus was identified as Sclerotium rolfsii. This is the first report on the sclerotium blight on Phalaenopsis spp. caused by Sclerotium rolfsii in Korea.

• Research in Plant Disease
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• v.16 no.3
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• pp.320-322
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• 2010

The Sclerotium blight was found on Neofinetia falcata at Yong-in city, Gyenggi-do, Korea. The symptom occurred low leaves yellowish and wilt of a whole plant. Severely infected plants were blighted and dies eventually. White mycelial mats appeared on the surface of basal stem and bulbs and the sclerotia were formed on stems, roots, and sphagnum moss. The sclerotia were spherical in shape, 1~3 mm in size and white to brown in color. The optimum temperature for the growth and sclerotia formation was $25{\sim}30^{\circ}C$ on PDA. On the pathogenicity test, the first symptom was appeared 5 days after inoculation and development to severe stem rot and blight. The causal fungus was identified as Sclerotium rolfsii and we suggested to call that the new Sclerotium blight on Neofinetia falcata caused by Sclerotium rolfsii in Korea.

• Journal of Bio-Environment Control
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• v.11 no.1
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• pp.18-22
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• 2002

Diseases occurrence of hydroponic culture was less than that of soil culture, especially gummy stem blight, which was 39.9-53.3% of infection rate at soil culture, was not almost observed at hydroponic culture. Development of fermented fruit was higher at Shintozoa, Hongtozoa and self-rooting seedling in order at soil cultured but critically dropped at hydroponic culture without rootstock sort. Therefore proper moisture management at root zone can decrease the development of fermented fruit.

• Mycobiology
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• v.38 no.3
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• pp.166-170
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• 2010

Gummy stem blight is a major foliar disease of muskmelon (Cucumis melo L.). In this study, morphological characteristics and rDNA internal transcribed spacer (ITS) sequences were analyzed to identify the causal organism of this disease. Morphological examination of the Jeonbuk isolate revealed that the percentage of monoseptal conidia ranged from 0% to 10%, and the average length $\times$ width of the conidia was 70 ($\pm$ 0.96) $\times$ 32.0 ($\pm$ 0.15) ${\mu}m$ on potato dextrose agar. The BLAST analysis showed nucleotide gaps of 1/494, 2/492, and 1/478 with identities of 485/492 (98%), 492/494 (99%), 491/494 (99%), and 476/478 (99%). The similarity in sequence identity between the rDNA ITS region of the Jeonbuk isolate and other Didymella bryoniae from BLAST searches of GenBank was 100% and was 95.0% within the group. Nucleotide sequences of the rDNA ITS region from pure culture ranged from 98.2% to 99.8%. Phylogenetic analysis with related species of D. bryoniae revealed that D. bryoniae is a monophyletic group distinguishable from other Didymella spp., including Ascochyta pinodes, Mycosphaerella pinodes, M. zeae-maydis, D. pinodes, D. applanata, D. exigua, D. rabiei, D. lentis, D. fabae, and D. vitalbina. Phylogenetic analysis, based on rDNA ITS sequence, clearly distinguished D. bryoniae and Didymella spp. from the 10 other species studied. This study identified the Jeonbuk isolate to be D. bryoniae.

• Journal of Plant Biotechnology
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• v.45 no.3
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• pp.217-227
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• 2018

Gummy stem blight (GSB) is one of the most destructive and economically important, soil borne diseases of melon caused by the ascomycete fungus, Didymella bryoniae throughout the world. In Korea, however, no GSB resistant genotype has been reported yet. The study aimed to identify GSB resistant melon germplasm. We screened a total of 60 genotypes including 16 lines and 44 melon cultivars collected from USA and Korea. Among the 16 melon lines, four lines including 'PI482399', 'PI140471', 'PI136170' and 'PI420145', and two Korean cultivars viz. 'Asia Papaya' and 'Supra' showed complete resistance. We were aware that both genotypic and environmental variations could influence the phenotypic screening of resistance and susceptibility. We therefore, further assessed all genotypes using 20 SSR markers. The SSR marker 'CMCT505' linked to Gsb1 in chromosome 1 perfectly grouped resistant and susceptible lines indicating that resistance is probably due to the presence of Gsb1 gene. Cloning and sequencing of resistant and susceptible Gsb1 amplicons showed that there were 32-bp deletions in resistant line and 39-bp deletions in resistant cultivar compared to susceptible one. Thus, the resistant melon lines and cultivars identified in this study could be recommended for the melon breeding program. Furthermore, the SSR marker 'CMCT505' which is tightly linked with Gsb1 could be used for molecular screening of melon germplasm.

• Research in Plant Disease
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• v.25 no.1
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• pp.29-32
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• 2019

Burcucumber (Sicyos angluatus) is a representative ecosystem-disturbing plant in Korea and currently widely spread throughout the country. A sclerotia-forming fungus with moderate host selectivity, Sclerotinia trifoliorum BWC98-105, was tested in the laboratory, green house and natural habitat for its pathogenicity to burcucumber. When mycelial culture fragment was inoculated to burcucumber seedlings under the green house condition, mycelial growth was observed in the following day, and then resulted in the onset of wilting from 5 days after inoculation (DAI). Its characteristic sclerotia as a sign was observed from 7 DAI, and thus plants turned into dark-brown color at the bottom of stem of burcucumber that was eventually blighted at 14 DAI. Similar visible symptoms were observed in natural habitat. Based on the results of showing typical blight symptom to burcucumber and the sign of sclerotia, we report S. trifoliorum BWC98-105 causing stem blight against burcucumber. Its globular pellet was considered of having quite potential as a bioherbicide to control burcucumber in Korea.

• Research in Plant Disease
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• v.7 no.2
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• pp.107-111
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• 2001

Deterioration of pod and seed quality by pod and stem blight and purple blotch is a serious problem in the production of vegetable soybean. Major inoculum sources for the causal pathogens, Phomopsis spp. and Cercospora kikuchii, are soybean straw and debris. Phomopsis spp. have been known to be either limited for hyphal growth or latent in immature soybean tissues. In this experiment, cultural practices using these ecological traits of the pathogens were applied as a control measure. In plastic mulching, seed infection was remark ably reduced by drip irrigation as compared to overhead sprinkling, but not reduced in no mulching cultivation. Control value of plastic mulching was 28.0% for pod and stem blight and 29.3% for purple blotch, which was lower than that of benomyl application. By the first week in June, 78% of overwintered soybean straw examined contained matured alpha spores in pycnidia, acting as primary inoculum. Secondary inoculum of phomopsix spp. was observed abundantly throughout from mid June to September on fallen cotyledons from current crops and subsequently was found on petiole debris. Consequently, both plastic mulching and drip irrigation were effective to some extent for controlling pod and stem blight and purple blotch without significant reduction in soybean yield, and the cultural practices in combination with field sanitation resulted in removing more the secondary inoculum.

• Journal of Bio-Environment Control
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• v.10 no.3
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• pp.187-196
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• 2001

Asparagus varieties popular in the foreign countries were collected and tested on their productivities and qualities for five years under rain shelter and open field conditions. Among the tested varieties, cultivars of UC309 and Excel showed superior productivity to the others in spear weight but the initial growth was not different among the tested varieties. However, the growth index was higher than the other varieties. According to the result from eight-year experiment, the best variety in productivity and quality were UC309 and Excel both for rain shelter and open field cultivations. To avoid the damage caused by stem blight, rain shelter and soil surface mulching treatments were tested with var. Excel. The spear sprouting and first harvesting date were a few days earlier in rain shelter cultivation than in open field, but there were no differences among the mulching materials. The number of spears and the spear weight per plant were increased in rain shelter cultivation, especially with rice straw and black P.E. mulching treatments. Marketable yield also increased by 253% in black P.E film mulching in rain shelter cultivation compared to non-mulching in open field. The stem blight examined in the autumn, 1997 was not observed under rain shelter treatment, but severe damage was observed in the open field regardless of the mulching materials. In the experiments, high asparagus yield could be achieved by black P.E. film mulching in rain shelter cultivation without the occurrence of stem blight.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.1
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• pp.50-54
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• 1984

To study the effects of planting dates and mulching on the growth and yield of summer type soybean, a variety, Damamidori introduced from Japan, was planted four times from April 13 with 10 days interval. Experimental plot in each planting date was devided into two sub-plots, polyethylene film mulching and non-mulching. By mulching, days to emergence and first flowering were shortened, especially in the early plantings; e.g. as much as 11 and 12 days, respectively, in the first planting. Compared to non-mulching, plant height, number of nodes of main stem, number of branches, and dry weight of stem and branches per unit area were also much increased by mulching. As the plantings were delayed, plant height, the total number of nodes and dry weight of main stem and branches, and 100 seed weight showed increasing trends, which were mainly due to lower infection rate of soybean seeds to pod and stem blight (Diaporthe phaseolorum) in the later plantings. The higher infection rate of soybean seeds to pod and stem blight, the lower infection rate to purple seed stain (Cercospora kikuchii) was shown in mulching but not in non-mulching.