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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Research in Plant Disease
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Journal DOI :
Korean Society of Plant Pathology
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Volume & Issues
Volume 17, Issue 3 - Dec 2011
Volume 17, Issue 2 - Aug 2011
Volume 17, Issue 1 - Apr 2011
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Alternative Sigma Factor HrpL of Pectobacterium carotovorum 35 is Important for the Development of Soft-rot Symptoms
Nam, Hyo-Song ; Park, Ju-Yeon ; Kang, Beom-Ryong ; Lee, Sung-Hee ; Cha, Jae-Soon ; Kim, Young-Cheol ;
Research in Plant Disease, volume 17, issue 2, 2011, Pages 111~120
DOI : 10.5423/RPD.2011.17.2.111
A bacterial artificial chromosome library of Pectobacterium carotovorum 35 was constructed to characterize the genome and to sequence its hrp region. The hrp cluster of P. carotovorum 35 consisted of 26 open reading frames in five operons. A promoter-based green fluorescent protein technology was used to identify the genes regulated by the alternative sigma factor, HrpL, in P. carotovorum 35. The majority of the selected clones contained the hrpJ operon promoter sequence, which harbors a hrp box, but no putative hrp boxes were detected within the promoter sequences of two other hrpL-regulated genes encoding for pectate lyase and large repetitive protein. Although the promoters of five other hrp operons also contained hrp boxes, their expression was not HrpL-dependent in the promoter-based selection in E. coli. However, transcriptional analysis showed that expression from all operons harboring hrp boxes, except for the hrpN operon, was reduced significantly in the hrpL mutant. The severity of soft-rot symptoms when the hrpL mutant was applied to the surface of tobacco leaves, mimicking natural infection, was greatly attenuated. These results indicate that the hrpL gene of P. carotovorum 35 may be involved in the development of soft-rot symptoms.
Biocontrol Activity of Myxococcus sp. KYC 1126 against Phytophthora Blight on Hot Pepper
Kim, Sung-Taek ; Yun, Sung-Chul ;
Research in Plant Disease, volume 17, issue 2, 2011, Pages 121~128
DOI : 10.5423/RPD.2011.17.2.121
Bacteriolytic myxobacteria have been known to secrete various antifungal metabolites against several soilborne phytopathogens including Phytophthora. Among the three isolates of Myxococcus spp., KYC 1126 and KYC 1136 perfectly inhibited the mycelial growth of Phytophtora capsici in vitro. In order to show the biocontrol activity on Phytophthora blight of hot pepper, we tried to find the best way of application of a myxobacterial isolate. Although KYC 1126 fruiting body was easily grown on the colony of Escherichia coli as a nutrient source, it did not control the disease when it was pre-applied in soil. Before the bioassay of a liquid culture filtrate of KYC 1126 was conducted, its antifungal activity was confirmed on the seedlings applying with the mixture of the pathogen`s zoospore suspension and KYC 1126 filtrate. On greenhouse experiments with five and four replications, the control value of KYC 1126 on phyllosphere and rhizosphere was 88% and 36%, respectively. Whereas, the control value of dimetnomorph+propineb on phyllosphere was 100% and that of propamorcarb on rhizosphere was 44%. There was a phytotoxicity of the myxobacterial filtrate when seedlings were washed and soaked for 24 hours. Gummy materials were covered with roots. And stem and petiole were constricted, then a whole seedling was eventually blighted.
Control of Late Blight of Tomato and Potato by Oilgochitosan
Cho, Yong-Ho ; Choi, Gyung-Ja ; Kim, Byung-Sup ; Jang, Kyoung-Soo ; Yoon, Mi-Young ; Park, Myoung-Soo ; Kim, Jin-Cheol ;
Research in Plant Disease, volume 17, issue 2, 2011, Pages 129~135
DOI : 10.5423/RPD.2011.17.2.129
Chitosan is a linear polysaccharide composed of randomly distributed
-(1-4)-linked D-glucosamine and Nacetyl-D-glucosamine. There have been many reports on the induced systemic resistance and in vivo antifungal activities of higher molecular weight chitosans with molecular weights over 3,000 amu (atomatic mass unit), but there are few papers on in vivo antifungal activities of low molecular weight chitosans (oligochitosans) with molecular weights less than 3,000 amu. In our study, an oligochitosan sample (320.3,000 amu) showed a potent 1-day protective activity with control values more than 94% at concentrations of 500 and 1,000
/ml especially against tomato late blight caused by Phytophthora infestans under growth chamber conditions. It also displayed a moderate 1-day protective activity with control values of 67.89% at concentrations of 500 and 1,000
/ml against wheat leaf rust and red pepper anthracnose. On the other hand, it showed a 16-hr curative activity against red pepper anthracnose, but not against tomato late blight and wheat leaf rust. In field experiments, oligochitosan effectively suppressed the development of late blight on potato and tomato plants with control values of 72% and 48%, respectively. The results strongly indicate that oligochitosan can be used as an eco-friendly organic material for the control of late blight on tomato and potato plants.
Control Efficacy of Nano-silver Liquid on Oak Wilt Caused by Raffaelea sp. in the Field
Kim, Sang-Woo ; Jung, Jin-Hee ; Lamsal, Kabir ; Kim, Yun-Seok ; Sim, Sang-Jun ; Kim, Ha-Sun ; Chang, Seok-Joon ; Kim, Jong-Kuk ; Kim, Kyoung-Su ; Lee, Youn-Su ;
Research in Plant Disease, volume 17, issue 2, 2011, Pages 136~141
DOI : 10.5423/RPD.2011.17.2.136
In other previous in vitro tests, the hyphal growth of Raffaelea quercivorus was inhibited by the treatments of various concentration of nano-silver. In this field tests, treatment of different concentrations of nano-silver to oak trees in Cheolwon and Hongcheon sites showed the inhibition effects against wilt disease caused by Raffaelea quercivorus. However, nano-silver-treated oak tree in Chuncheon site showed mild wilt symptoms with no phytotoxicity. Scanning electron microscope (SEM) observation confirmed that the spore and hypha of Raffaelea sp. inside the vessels were damaged by nano-silver. This result indicates the application of nanosilver is effective for control of Raffaelea quercivorus in the field.
Determination of Proper Application Timing and Frequency for Management of Tomato Leaf Mold Disease by Commercially Available Microbial Preparations
Kang, Beom-Ryong ; Ko, Sug-Ju ; Kim, Do-Ik ; Choi, Duck-Soo ; Kim, Seon-Gon ;
Research in Plant Disease, volume 17, issue 2, 2011, Pages 142~147
DOI : 10.5423/RPD.2011.17.2.142
In order to develop a environmentally friendly control protocol for managing tomato leaf mold disease in the field, we employed bacteria- and fungi-based commercially available microbial preparations. The field experiment was conducted from April to July in 2010. Average incidence rates tomato leaf mold caused by Fulvia fulva were 13.1% at the two plastic houses located in Jangsung, Jeonnam area. Initially 11 microbial preparations were tested for antifungal activity against F. fulva in vitro. Among them, 7 selected preparations showed to be inhibited the mycelial growth of the fungal pathogen over 50%. Four microbes suppressed disease incidence as much 50% under greenhouse condition. Eventually in the field two microbial products including Bacillus subtilis GB-0365 and B. subtilis KB-401 respectively were showed control value up to 71.8% for four times sprays from 20 days to 70 days after transplanting. Furthermore, the control value of three times spray program demonstrated 79.3%. Efficacy of the three and four spray programs was more effective than that of non-spray control treatment. Our results indicated that adjustment of application method of commercially available microbial preparation could be used to control a target plant disease as an effective and efficient crop protection system for organic farming.
Screening of Seed Treatment Agents against Leaf Blight and Black Root Rot for Carrot Organic Cultivation
Lee, Jae-Eun ; Yeoung, Young-Rok ; Kwon, Soon-Bae ; Kim, Byung-Sup ;
Research in Plant Disease, volume 17, issue 2, 2011, Pages 148~154
DOI : 10.5423/RPD.2011.17.2.148
This study was conducted to control the seed borne pathogens (Alternaria spp.) of carrot and to examine the seed germination rate by using 13 environment friendly agricultural materials instead of conventional chemicals for organic cultivation. The growth inhibiting effects on pathogens showed the different responses according to each agricultural material and effective 7 materials against seed borne pathogens were selected. Among 7 materials, the carrot seeds sterilized with plant extracts, Tanger Stop and Land Saver were not germinated at all. The germination rate of seeds sterilized with other materials showed the similar levels with reference chemical (Benlate-T) and non-treated seeds. Infection rates of seeds sterilized with seaweed extract, Bellopper for controlling A. radicina and plant extract, Ssial-100 for A. dauci were similar or low infection rate compared with reference chemical. The germination rate and root length of seeds sterilized with Bellopper and Ssial-100 was similar or superior to those of chemical sterilized seeds. The optimal condition seemed to be a little bit different depending on the concentration of materials. As a result, the sterilization of carrot seeds by using the environment friendly materials could be effectively utilized as a technology to inhibit the infection of seed-borne pathogens.
Control Efficacy of Fungicides on Chinese Cabbage Clubroot under Several Conditions
Eom, Min-Yong ; Jo, Su-Jung ; Jang, Kyoung-Soo ; Choi, Yong-Ho ; Kim, Jin-Cheol ; Choi, Gyung-Ja ;
Research in Plant Disease, volume 17, issue 2, 2011, Pages 155~160
DOI : 10.5423/RPD.2011.17.2.155
To develop the efficient screening methods for antifungal compound active to Chinese cabbage clubroot caused by Plasmodiophora brassicae, the control efficacy of three fungicides fluazinam, ethaboxam, and cyazofamid on the disease was tested under several conditions such as soil types, cultivars of Chinese cabbage, growth stages of the host, and inoculum concentrations. The in vivo antifungal activities of the fungicides on clubroot of two Chinese cabbage cultivars were hardly different. At 7- and 14-day-old seedlings, the fungicides were more effective to control of clubroot than at 21-day-old seedlings. In a commercial horticulture media soil (CNS), disease severity of untreated controls was higher and control activity of the fungicides was less than in a mixture of CNS and upland soil (1:1, v/v). Disease development of the seedlings inoculated with P. brassicae at
spores/pot was almost same, but control efficacy of the fungicides was negatively correlated with inoculum dosages. To effectively select in vivo antifungal compound on Chinese cabbage clubroot, 14-day-old seedlings need to be inoculated with P. brassicae by drenching the spore suspension to give
spores/pot 1 day after chemical treatment. To develop clubroot, the inoculated plants are incubated in a growth chamber at
for 2 days, and then cultivated in a greenhouse (
) for four weeks.
Development of Convenient Screening Method for Resistant Radish to Plasmodiophora brassicae
Jo, Su-Jung ; Jang, Kyoung-Soo ; Choi, Yong-Ho ; Kim, Jin-Cheol ; Choi, Gyung-Ja ;
Research in Plant Disease, volume 17, issue 2, 2011, Pages 161~168
DOI : 10.5423/RPD.2011.17.2.161
To establish simple and reliable screening method for resistant radish to Plasmodiophora brassicae Woron. using soil-drenching inoculation, the development of clubroot on radish seedlings inoculated with P. brassicae GN-1 isolate according to several conditions such as inoculum concentration, plant growth stage and incubation period after inoculation was studied. To select resistant radish against clubroot, 10-day-old seedlings were inoculated with P. brassicae by drenching the roots with the spore suspension of the pathogen to give
spores/pot. The inoculated seedlings were incubated in a growth chamber at
for 3 days then cultivated in a greenhouse (
) for 6 weeks. Under the optimum conditions, 46 commercial cultivars of radish were tested for resistance to YC-1 (infecting 15 clubroot-resistant cultivars of Chinese cabbage) and GN-1 (wild type) isolates of P. brassicae. Among them, thirty-five cultivars showed resistance to both isolates and one cultivar represented susceptible response to the pathogens. On the other hand, the other cultivars showed different responses against the tested P. brassicae pathogens. The results suggest that this method is an efficient system for screening radish with resistance to clubroot.
Molecular Characteristics of Phytophthora katsurae Using PCR-SSCP Analysis
Lee, Sun-Keun ; Jang, Ha-Na ; Lee, Dong-Hyeon ; Lee, Sang-Hyun ; Lee, Sang-Yong ; Lee, Jong-Kyu ;
Research in Plant Disease, volume 17, issue 2, 2011, Pages 169~176
DOI : 10.5423/RPD.2011.17.2.169
Phytophthora katsurae is the fungus responsible for chestnut ink disease. The objectives of this study were to determine if a single-strand conformation polymorphism (SSCP) analysis of rDNA-ITS region, elongation factor 1 alpha gene and
-tubulin gene could be used for rapid identification and genetic diversity of P. katsurae, and to assess the potential use of the SSCP technique as a diagnostic tool for P. katsurae. Each regions amplified by PCR using primers designed to overlap the genus Phytophthora were characterized for the Phytophthora species. PCR products were denatured and electrophoresed for SSCP analysis. P. katsurae isolates showed an unique pattern in SSCP analysis and were easily distinguished from other Phytophthora species used as the control. This indicates that SSCP analysis is an useful technique for distinguishing Phytophthora species from genetically close relatives, and show that the SSCP analysis of each region is an efficient detection tool for P. katsurae. But PCR-SSCP analysis of single-gene may have difficulty in distinguishing P. katsurae from other Phytophthora species. Therefore, PCR-SSCP analysis of multi-genes can be useful for rapid and effective identification of P. katsurae.
Effects of Fusarium circinatum on Disease Development and Gas Exchange in the Seedlings of Pinus spp.
Woo, Kwan-Soo ; Yoon, Jun-Hyuck ; Han, Sang-Urk ; Woo, Su-Young ;
Research in Plant Disease, volume 17, issue 2, 2011, Pages 177~183
DOI : 10.5423/RPD.2011.17.2.177
Four-year-old seedlings of Pinus thunbergii, Pinus densiflora and Pinus rigida were inoculated with Fusarium circinatum isolate (FT-7), the pitch canker fungus, from P. thunbergii, to evaluate the effects of the pathogen on disease development and gas exchange rate. Needle dehydration was evident on 2 of 10 seedlings of P. thunbergii and P. rigida at 18 and 21 days after inoculation, respectively, while no symptoms were observed in P. densiflora seedlings throughout the experiment. Gas exchange stopped completely in 4 of 5 measured seedlings of P. thunbergii and 2 of 5 measured seedlings of P. rigida at 25 days after inoculation, and in the remaining 3 seedlings of P. rigida at 39 days after inoculation. Disease development in P. thunbergii seedlings was faster than that in P. rigida seedlings. By the time, the experiment was ended at 78 days after inoculation, 9 of 10 seedlings of P. rigida and 8 of 10 seedlings of P. thunbergii seedlings treated with FT-7 was almost dead, but all seedlings of P. densiflora were still healthy. We suggest that P. densiflora is resistant to F. circinatum in the current study, and gas exchange rate of the species after inoculation does not differ significantly compared to that of untreated control.
Detection of the Causal Agent of Bacterial Wilt, Ralstonia solanacearum in the Seeds of Solanaceae by PCR
Cho, Jung-Hee ; Yim, Kyu-Ock ; Lee, Hyok-In ; Baeg, Ji-Hyun ; Cha, Jae-Soon ;
Research in Plant Disease, volume 17, issue 2, 2011, Pages 184~190
DOI : 10.5423/RPD.2011.17.2.184
Ralstonia solanacearum, a causal agent of bacterium wilt is very difficult to control once the disease becomes endemic. Thus, Ralstonia solanacearum is a plant quarantine bacterium in many countries including Korea. In this study, we developed PCR assays, which can detect Ralstonia solanacearum from the Solanaceae seeds. Primers RS-JH-F and RS-JH-R amplified specifically a 401 bp fragment only from Ralstonia solanacearum race 1 and race 3. The nested PCR primers, RS-JH-F-ne and RS-JH-R-ne that were designed inside of 1st PCR amplicon amplified specifically a 131 bp fragment only from Ralstonia solanacearum race 1 and race 3. The primers did not amplify any non-specific DNA from the seed extracts of the Solanaceae including tomato and pepper. When detection sensitivity were compared using the Solanaceae seeds inoculated with target bacteria artificially, the nested PCR method developed in this study 100 times more sensitive than ELISA and selective medium. Therefore, we believe that the PCR assays developed in this work is very useful to detect Ralstonia solanacearum in the Solanaceae seeds.
Cause of the Scion Death in Green Pepper Grafting System by a Tobamovirus
Choi, Gug-Seoun ; Cho, Jeom-Deog ; Chung, Bong-Nam ; Cho, In-Sook ; Choi, Sung-Kook ;
Research in Plant Disease, volume 17, issue 2, 2011, Pages 191~195
DOI : 10.5423/RPD.2011.17.2.191
This experiment was attempted to investigate a cause of the scion death in green pepper grafting system. A tobamovirus particle examined in the rootstock of the sample but not in the scion showing necrosis. The virus isolated from the rootstock was identified as Pepper mild mottle virus (PMMoV), pepper tobamovirus pathotype P1.2. (PMMoV-2), by nucleotide sequence analysis and host plant reaction. The virus isolate infected systematically in 6 commercial rootstock varieties using for green pepper grafting seedling production. Green pepper varieties `Long green mart` and `Daechan` represented resistance to the virus showing local lesions only on the inoculated leaves and `Manitda` was systematically infected. In the experiment with grafting `Long green mart` or `Daechan` onto the those rootstocks, the upper leaves of the scions first showed vein necrosis and wilt symptoms 7 days after inoculation with PMMoV-2 on the cotyledon of the rootstock, following to the scion stem necrosis and then only the scion death. The virus was detected in the rootstock but not in the scion. However, `Manitda` of susceptible variety in the grafting system showed mottle symptom on the leaves of the scion but not necrosis on the plant. PMMoV-3 isolate, pepper tobamovirus pathotype P1.2.3, did not cause the scion death in the grafting system. All of the varieties were susceptible to PMMoV-3. These results suggest that the scion death is caused by infecting with pepper tobamovirus pathotype P1.2. in the green pepper grafting system combined with the susceptible rootstock and the resistance scion to the virus pathotype.
Symptoms of Cucumber Virus Diseases Occurred in Sangju and Gurye in 2006 and 2007
Cho, Jeom-Deog ; Lee, Jung-Hwan ; Ko, Sug-Ju ; Choi, Hong-Soo ; Lee, Su-Heon ; Choi, Gug-Seoun ; Kim, Jeong-Soo ;
Research in Plant Disease, volume 17, issue 2, 2011, Pages 196~204
DOI : 10.5423/RPD.2011.17.2.196
Virus diseases occurring on cucumber was surveyed at main plantation areas of `Sangju` and `Gurye` in 2006 and 2007. Viral infection rate on cucumber was ranged from 14% to 90% in fields and the average infection rate was 46% at Sangju area. Cucumber cultivated at Gurye area had viral incidence ranged 9-100% and averaged 48%. The majorly infected viruses were Cucumber green mottle mosaic virus, Zucchini yellow mosaic virus, Papaya ring spot virus and Watermelon mosaic virus-2, and their infection rates were 23.5%, 13.0%, 9.0% and 2.0%, respectively in 2006 and 2007. Mixed infection rate of duplex, triplex and tetraplex was 31.5%, 7.5% and 2.5%, respectively. The rate of infection type was 47.7% by single infection, 31.5% by double infection and 88.7% by both infection types. Important viruses involved in mixed infection types were Zucchini yellow mosaic virus, Cucumber green mottle mosaic virus, Papaya ring spot virus and Broad been wilt virus2, orderly. Symptom in single infection was almost same on `Dadagi` line and `Chicheong` line of cucumber cultivars. Cucumber green mottle mosaic virus produced various symptoms of chlorotic spot, vein chlorosis and vein wrinkle and so on. Main symptoms of vein chlorosis, and severe mosaic and malformation were induced by Zucchini yellow mosaic virus. Mild symptoms were occurred relatively by Papaya ring spot virus and Watermelon mosaic virus2.
Disease Occurrence on Red-pepper Plants Surveyed in Northern Kyungbuk Province, 2007-2008
Seo, Ji-Ae ; Yi, Young-Keun ; Kim, Byung-Soo ; Hwang, Jae-Moon ; Choi, Seak-Won ;
Research in Plant Disease, volume 17, issue 2, 2011, Pages 205~210
DOI : 10.5423/RPD.2011.17.2.205
The disease occurrence on red-pepper plants in relation to cultivation methods of the farmers and to the precipitation was investigated in northern Kyungbuk Province. The major diseases were mosaic, anthracnose and Phytophthora blight in 2007 and 2008. In 2008, mosaic was more severe than that in 2007, but the other diseases were milder than those in 2007. A negative correlation between the mosaic incidence in the harvesting season and the precipitation during May was recognized. On the other hand, there was a positive correlation between the severity of Phytophthora blight in September and the precipitation during August. The occurrence of anthracnose, Phytophthora blight and mosaic in the surveyed pepper plants grown in plastic houses were milder than those in fields, although the farmers cultivating red-pepper plants in the plastic houses were less than 5% in the northern Kyungbuk Province.
Characterization of an Isolate of Cucumber mosaic virus from Raphanus sativus L.
Rhee, Sun-Ju ; Hong, Jin-Sung ; Choi, Jang-Kyung ; Kim, Eun-Ji ; Lee, Gung-Pyo ;
Research in Plant Disease, volume 17, issue 2, 2011, Pages 211~215
DOI : 10.5423/RPD.2011.17.2.211
Cucumber mosaic virus (CMV)-like isolate was collected from Raphanus sativus (cv. Choon-hyang), which showed mosaic symptoms. The isolate was confirmed to a strain of CMV by host responses in Vigna unguiculata, Chenopodium amaranticolor and Gomphrena globosa, by viral genome composition with RT-PCR and PCR-RFLP, and by serological analysis. Symptom developed by the strain of CMV was severe in Nicotiana benthamiana, N. glutinosa, N. tabacum (cv. Samsun, cv. Xanthi), Cucumis melo (cv. Early hanover), Cucumis sativus (cv. White wonder), Capsicum annuum (cv. Chung-yang and cv. Geum-top), but mild symptom was developed in Raphanus sativus (cv. Choon-hyang), Brassica rapa ssp. pekinensis (cv. Bul-Am No. 3), and B. juncea (cv. Daenong Jukgot). Newly isolated strain of CMV could infect diverse crops including Solanaceae, Cucurbitaceae and Brassicaceae. We designated the new strain of CMV as Gn-CMV based on the novel infectivity of Brassicaceae. In double-stranded (ds) RNA analysis, Gn-CMV consisted of 3.3, 3.0, and 2.2 kb genomes likewise other strains of CMV. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) showed 28 kDa of the CMV coat protein. By restriction enzyme mapping using Cac8I, ClaI and MspI of RT-PCR products indicated that Gn-CMV belongs to CMV subgroup I.
First Detection of Penicillium fellutanum from Stored Rice in Korea
Oh, Ji-Yeon ; Sang, Mee-Kyung ; Lee, Ho-Joung ; Ryoo, Mun-Il ; Kim, Ki-Deok ;
Research in Plant Disease, volume 17, issue 2, 2011, Pages 216~221
DOI : 10.5423/RPD.2011.17.2.216
A representative isolate KU53 of the predominant Penicillium species was obtained from rice samples from rice processing complexes of National Agricultural Cooperative Federation in Korea. In this study, isolate KU53 was identified by its morphological and molecular characteristics. The macro- and microscopic characteristics of isolate KU53 were compared with the P. fellutanum reference isolate KCTC16913 on different media; isolate KU53 was generally identical to those of the reference isolate KCTC16913. In a molecular-based identification, the
-tubulin and translation elongation factor 1-alpha sequences of isolate KU53 was most closely related to those of P. fellutanum. Thus, isolate KU53 from stored rice could be identified as P. fellutanum, some isolates of which are known to produce mycotoxin-related metabolites. To our knowledge, this is the first detection of P. fellutanum from stored rice in Korea.
Sclerotium Rot of Onion Caused by Sclerotium rolfsii
Kwon, Jin-Hyeuk ; Kim, Hee-Dae ; Choi, Ok-Hee ; Kwak, Youn-Sig ; Lee, Yong-Hwan ; Shim, Hong-Sik ;
Research in Plant Disease, volume 17, issue 2, 2011, Pages 222~224
DOI : 10.5423/RPD.2011.17.2.222
The sclerotium rot of onion (Allium cepa L.) was occurred sporadically in the farmer`s fields at Daehap, Changnyeong in Korea. The typical symptom was water-soaking on the bulb, stem and leaves and then rotting, wilting, blighting and the infected plants eventually were rotted and died. The sclerotia were globoid, 1-3 mm, and white to brown. The optimum temperature for mycelial growth and sclerotial formation on PDA was
. The hyphal width was 4-9
. The typical clamp connections were observed in the hyphae of the fungus grown on PDA. On the basis of mycological characteristics, ITS rDNA sequence analysis, and pathogenicity, this fungus was identified as Sclerotium rolfsii Saccardo. To our knowledges, this is the first report of sclerotium rot on onion caused by S. rolfsii in Korea.
Occurrence and Characterization of Stem Rot of Chrysanthemum zawadskii var. latilobum Caused by Sclerotium rolfsii
Kim, Chang-Su ; Lee, Wang-Hyu ; Kim, Jeong-Man ;
Research in Plant Disease, volume 17, issue 2, 2011, Pages 225~227
DOI : 10.5423/RPD.2011.17.2.225
The stem rot of Chrysanthemum zawadskii var. latilobum occurred in the landscape field of Sanggwan-myeon, Wanju-gun, Jeonbuk, Korea in September 2009. The typical symptoms of the disease were water-soaking and dark brown rot on the stem, wilting and blighting. Most infected plants died of the disease. White mycelial mats were spread over lesions and brown sclerotia were formed on stems and near soil surface. The sclerotia were spherical or irregular, 0.8-3.5 (mean 1.8) mm in size on potato dextrose agar, brown in color. The optimal temperature range of hyphal growth was
and the hyphal diameter was 4-9
. Clamp connections were observed in the hyphae of the fungus grown on potato dextrose agar. Pathogenicity of the casual organism was provided on C. zawadskii according to Koch`s postulate. The fungus was identified as Sclerotium rolfsii on the basis of mycologiclal characteristics and pathogenicity test to host plants. This is the first report on the stem rot of C. zawadskii caused by S. rolfsii in Korea.
Occurrence of Leaf Spot on Eriobotrya japonica Caused by Entomosporium mespili in Korea
Seo, Sang-Tae ; Park, Mi-Jeong ; Shin, Hyeon-Dong ; Kim, Kyung-Hee ;
Research in Plant Disease, volume 17, issue 2, 2011, Pages 228~231
DOI : 10.5423/RPD.2011.17.2.228
Since 2008, a new leaf spot disease has been found in loquat tree (Eriobotrya japonica) at a nursery station in Goheung, Korea. Above 50% of the seedlings developed the spot symptoms on the leaves. The infected plants were generally reduced in the seedling vigour and early defoliation was occurred. The infected leaves developed grayish lesion with dark reddish brown margin. The pathogen developed round to ellipsoidal acervuli on the lesion. Based on morphological characteristics of the pathogen, the fungus was identified as Entomosporium mespili. The cultured pathogen successfully reproduced the same disease symptom on the leaves of loquat tree and found to be E. mespili. A monoconidial culture was deposited in Korean Agricultural Culture Collection (KACC 44727). This is the first report of E. mespili causing leaf spot of loquat tree in Korea.
First Report of Sour Rot on Post-harvest Oriental Melon, Tomato, Cucumber, Potato, Pumpkin and Carrot Caused by Geotrichum candidum
Kim, Yong-Ki ; Kim, Taek-Soo ; Shim, Hong-Sik ; Park, Kyung-Seok ; Yeh, Wan-Hae ; Hong, Sung-Jun ; Shim, Chang-Ki ; Kim, Jeong-Soon ; Park, Jong-Ho ; Han, Eun-Jung ; Lee, Min-Ho ; Jee, Hyeong-Jin ;
Research in Plant Disease, volume 17, issue 2, 2011, Pages 232~234
DOI : 10.5423/RPD.2011.17.2.232
During survey of postharvest diseases of vegetables in the middle region of Korea in 2003, 2004 and 2005, new disease symptoms showing watery rot and soft rot were observed. In this study, the disease causal agents were identified as Geotrichum candidum, and their host range and pathogenicity were investigated. G. candidum isolated had wide host range and strong pathogenicity against carrot, cucumber, tomato and pumpkin. The disease occurrence on several vegetables that G. candidum can be a serious threat to stable production of fresh vegetable.