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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 10, Issue 4 - Dec 2004
Volume 10, Issue 3 - Sep 2004
Volume 10, Issue 2 - Jun 2004
Volume 10, Issue 1 - Mar 2004
Selecting the target year
Ecology of Disease Outbreak of Circular Leaf Spot of Persimmon and Inoculum Dynamics of Mycosphaerella nawae
Kwon, Jin-Hyeuk ; Park, Chang-Seuk ;
Research in Plant Disease, volume 10, issue 4, 2004, Pages 209~216
DOI : 10.5423/RPD.2004.10.4.209
The circular leaf spot of persimmon is occurred almost every place where persimmon is cultivated, especially the disease outbreak severely in southern part of Korea. The disease reveals unusually long incubation period after pathogen invade into leaf tissue and no practical control measure is available once the symptom has appeared. Most of the farmers just follow the suggested spray schedules calculated on the basis of weather condition of ordinary years. Therefore the damages due to circular leaf spot greatly differ year after year. In this article, we tried to describe and summarized the investigation on the circular leaf spot pathogen, Mycosphaerella nawae, related to disease outbreak such as overwintering of pathogen, inoculum formation and spread, incubation period after infection, and secondary inoculum. With the summary of these results, we suggest the disease cycle of circular leaf spot of persimmon. The pathogen overwinters in diseased leaves as mycelial form or pseudoperithecial premodium. The pseudoperitheria become matured in spring as the temperature raise and forms asci and ascospores. The maturation of pseudoperithecia are closely related to the temperatures during March and early April. The ascospores completely mature in early May and the ascospores released when the pseudoperithecia absorbed enough moisture after rainfall. The release of ascospores are diverse greatly with the variation of maturity of pseudoperithecia. Generally the spore start to release from middle of May to early of July. Duration of ascospore release is depend on the weather condition of particular year, especially amount and number of precipitation. The ascospores produced from pseudoperithecia is known to the only inoculum for circular leaf spot disease. But according to the results obtained from our investigations, the conidia formed on the lesions which incited by natural infection. This conidia are infectious to persimmon leaves and formed identical symptom as natural infection. The time of producing secondary inoculum of circular leaf spot of persimmon is considered too late to develop new disease. Generally the importance of secondary inoculum is low but the conidia produced in early September are competent to develop new disease and new infection also significantly affect to harvest of persimmon. The importance of circular leaf spot disease is recognized well to farmers. The approaches to control of the disease should be initiated on the basis of the knowledges of inoculum dynamics and ecology of disease development. The forecasting system for circular leaf spot is need to be developed.
Comparative Assay Fungus Population and Resistant Genes about Magnaporthe grisea between Korea and China
Kim, Dong-Yun ; Shim, Hong-Sik ; Cailin, Lei ; Ling, Zhong Zhuan ; Han, Seong-Sook ;
Research in Plant Disease, volume 10, issue 4, 2004, Pages 217~226
DOI : 10.5423/RPD.2004.10.4.217
One hundred isolates of Magnaporthe grisea from Korea and China were characterized for pathogenicity using eight Korean differential varieties(KDV), six Chinese differential varieties(CDV) and six near isogenic lines(NILs) developed in China. The restriction length polymorphism of M. grisea isolates from each country also was analyzed using MGR586 as a probe. One hundred Korean isolates classified into 17 races on KDV were grouped into 29 pathotypes on Chinese near isogenic lines(NILs). Virulence of 46% of Korean isolates against all the six Chinese NILs indicated that the current six Chinese NILs alone was not enough to be used as differential varieties in Korea. Especially, susceptibility of the BL1 carrying resistance gene Pi-b to 70% of tested Korean isolates suggested that BL1(Pi-b) may not be a useful resistance source to Korean blast. Based on the virulence assays of M. grisea populations from each country were divided into two groups. About 50% of Chinese isolates showed similarity to the 30% of the Korean isolates. Especially, the isolates from northern part of China, where Japonica rice cultivars were grown, showed high similarity to the Korean isolates, while isolates from southern part of China, where Indica rice were mainly grown, showed low similarity to Korean isolates. The genome RFLPs of Korean isolates were quite different from those of southern part of China using MGR586 as a probe. These data indicated that the physiological and genetical characteristics of M. grisea population might be determined by strong interaction with cultivated rice.
Epidemiology of the Crown Gall (Agrobacterium tumefaciens) of Persimmon Tree
Kim, Seung-Han ; Lim, Yang-Sook ; Choi, Seong-Yong ; Kim, Dong-Geun ; Choi, Sung-Kook ; Yoon, Jae-Tak ;
Research in Plant Disease, volume 10, issue 4, 2004, Pages 227~230
DOI : 10.5423/RPD.2004.10.4.227
Occurrence and epidemiology of crown gall caused by A. tumefaciens in persimmon tree was investigated. Persimmon tree was more sensitive to crown gall disease than peach and jujube tree. Over 80% persimmon trees were infected to crown gall in all investigated region with no relation to planted years. Yield of infected tree was severely decreased to 54%. Incidence of crown gall in nursery field of persimmon tree was also severe and the infection rate of persimmon seedlings collected from market was 34%. It was guessed that the primary inoculum of crown gall caused by A. tumefaciens is infected persimmon seedlings.
The Incidence and Distribution of Viral Diseases in Pepper by Cultivation Types
Lee, Su-Heon ; Lee, Jae-Bong ; Kim, Sang-Mok ; Choi, Hong-Soo ; Park, Jin-Woo ; Lee, Jun-Seong ; Lee, Key-Woon ; Moon, Jae-Sun ;
Research in Plant Disease, volume 10, issue 4, 2004, Pages 231~240
DOI : 10.5423/RPD.2004.10.4.231
In the year of 2002 annual nationwide survey of virus diseases occurring in the pepper fields and greenhouses in Korea, the distribution and the incidence of viral diseases was investigated. The pepper samples from both greenhouses (155 samples) and open fields (227 samples) were collected and further analyzed to detect eleven different viruses by RT-PCR. The results indicate that no sample collected from both greenhouse and open field seems to be infected by TMV, RMV, PVY, AMV, and TSWV. On the other hand, CMV, BBWV2, PepMoV, PMMoV, TMGMV and ToMV are readily identified from greenhouse and open field samples by RT-PCR. The infection rates of the collected samples between greenhouse and open field are largely different. Comparing with 10% of virus-infected pepper samples grown in greenhouse, approximately one third of pepper samples collected from open field are infected. The mixed-infection rates in the virus-infected greenhouse and open field samples are 16% and 61%, respectively. The dominant virus occuring in greenhouse is PMMoV, indicating that virus-infected seed stocks and infected plant debris in the growing area may be important sources of inocula. On the other hand, both CMV and BBWV2 are dominant viruses in open field. This may indicate that the migration of viruliferous insect vectors into pepper fields may be the most important source of inoculum. Also, the survey shows that BBWV2 is newly immerging virus to be controlled in Korea. The discrepancies on the distribution and the occurrence of viral diseases between field and greenhouse may provide a fact that the accumulation and distribution of inoculum by successive cultivation and the migration of viruliferous vectors into growing areas are likely to be important factors to determine the incidence of viral diseases. Therefore, the further studies on epidemiology and the consideration of new breeding program of pepper are essential to minimize virus diseases.
Genomic Analysis of Satellite RNA of Cucumber mosaic virus-Paf Related with Mild Symptoms
Sung, Mi-Young ; Jung, Min-Young ; Lee, Sang-Yong ; Ryu, Ki-Hyun ; Choi, Jang-Kyung ;
Research in Plant Disease, volume 10, issue 4, 2004, Pages 241~247
DOI : 10.5423/RPD.2004.10.4.241
Recently, we reported a satellite RNA (Paf-satRNA) which is encapsidated in a pepper isolate of Cucumber mosaic virus (CMV-Paf) regulated symptom attenuation of the helper virus. To characterize mild symptom domain of Paf-satRNA, a series of chimeric cDNAs of satRNAs were created by using full-length cDNA clones of Paf-satRNA and a Pep-satRNA, chlorosis-inducing satRNA in pepper plants, and analyzed for determinants of symptom attenuation. When compared the nucleotide sequences, the 3' and 5' terminal sequences of the two wild-type (wt) satRNAs contained relatively conserved sequences which are the typical to CMV satRNA. Ten bases insertions were found in PepY-satRNA, and two variable regions, 81st to 113th and 183rd to 265th from the 5'-end, were located in the middle parts of the satRNAs. To delineate the attenuated symptom-related domain for the Paf-satRNA, in vitro transcripts RNAs transcribed from the wt cDNAs and constructed chimeric cDNAs were combined with genomic RNAs, RNA1, RNA2 and RNA3, of CMV-Fny and inoculated onto Nicotiana benthamiana plants. These transcripts were fully infectious onto the N. benthamiana and infectivity was confirmed by the RT-PCR. Chimeric Paf(H/N)-satRNA and PepY(N/A)-satRNA as well as Paf-satRNA induced very mild mosaic or symptomless infection on N. benthamiana. By contrast, typical mosaic symptom and stunting of infected plants were induced when PepY-satRNA, PepY(H/N)-satRNA and Paf(N/A)-satRNA were infected to N. benthamiana. Paf-satRNA coinfected with CMV-Fny RNAs induced very mild to sympomless on pepper plants whereas PepY-satRNA-infected pepper expressed typical chlorosis mosaic symptom. Two kinds of chimeric mutants, Paf(H/N)-satRNA and PepY(N/A)-satRNA, induced mild mosaic or symptomless infection onto pepper plants, while PepY(H/N)-satRNA and Paf(N/A)-satRNA showed typical chlorosis and mosaic symptom with stunting. This results suggest that mild symptom-related domain for the Paf-satRNA was located on HpaI-NarI region.
Fusarium species Associated with Ginseng (Panax ginseng) and Their Role in the Root-Rot of Ginseng Plant
Lee, Soon-Gu ;
Research in Plant Disease, volume 10, issue 4, 2004, Pages 248~259
DOI : 10.5423/RPD.2004.10.4.248
A total 115 isolates of Fusarium species from ginseng roots of 'rotted', and soils collected during 1982-1985 in Korea, were identified and classified into 11 species with the Snyder & Hansen System (with reference to Gerlach-Nirenberg's Modified System). The most dominant of these species were F. solani (55 isolates), F. oxysporum (35 isolates), and F. moniliforme (10 isolates) sensu Snyder & Hansen. The other 8 species (15 isolates) were very rarely isolated and previously identified as F. roseum sensu Snyder & Hansen (1945); these were F. equiseti, F. avenaceum, F. graminum, F. arthrosporioides, F. sambucinum, F. reticulatum, F. semitectum and F. poa. Tested for the ability to infect the roots of ginseng (3 yr. old plants) in field condition with the mycelial inoculum, only one isolate of F. solani (34 isolates tested) and one isolate of F. oxysporum (24 isolates tested) were weakly pathogenic to ginseng roots. Any of the isolates (7 isolates tested) of F. moniliforme [Liseola section] were not pathogenic to ginseng. However, all the isolates of tested of the species of Phytophthora cactorum, Pythium ultimum, and Cylindrocarpon destructans were highly pathogenic to ginseng roots. The species of Fusarium solani and Cylindrocarpon destructans were supposed to be a host dominant disease agent in ginseng plant.
Fusarium Fruit Rot of Posthavest Oriental Melon (Cucumis melo L. var. makuwa Mak.) Caused by Fusarium spp.
Kim, Jin-Won ; Kim, Hyun-Jin ;
Research in Plant Disease, volume 10, issue 4, 2004, Pages 260~267
DOI : 10.5423/RPD.2004.10.4.260
Fusarium spp. were isolated from the postharvest fruit rot of oriental melon fruits at commercial fruit markets in Korea during 2001 to 2003. The decayed fruits were covered with the fungal mycelia and eventually soft rotted. The disease started at the fruit stalk area, the calyx end of the fruit and skin of fruit. As the disease advanced, white to pinkish mycelia covered with the surface of decayed fruit. The cultural and morphological characteristic of Fusarium spp. were compared with descriptions of those reported previously, and identified as Fusarium equiseti, F. graminearum, F. moniliforme, F. proliferatum, F. sambucinum, and F. semitectum. Pathogenicity of the isolates was proved by artificial wound and unwound inoculation onto the healthy fruits. Two days after inoculation, aerial mycelia were noticed on the wound inocultion region of the fruit and developed soft rot symptoms. Although Fusarium spp. causing fruit rot disease in oriental melon have been reported in Korea, identification of the those species was not described. Therefore, this is the first report of Fusarium spp. causing postharvest fruit rot on oriental melon in Korea.
Occurrence and Control of Black Root Rot of Peony (Paeonia lactiflora) on Continuous Cropping
Choi, Seong-Yong ; Park, Kyeng-Seok ; Kim, Ki-Jae ; Kim, Jae-Cheol ;
Research in Plant Disease, volume 10, issue 4, 2004, Pages 268~271
DOI : 10.5423/RPD.2004.10.4.268
Occurrence and soil fumigation effect on black root rot of peony was investigated. Peony was severely infected to black root rot caused by Cylindrocarpon destructans in continuous cropping field, but in first cropping field was less infected. To control black root rot, soil improvement, soil fumigation and the root dipping in chemicals were trialed in peony continuous cropping field. Black root rot was not decreased by soil improvement, but incidence of black root rot of peony cultivated in continuous croping field of peony was decreased by soil fumigation with Dazomet GR. and dipping of peony root in chemicals.
Dissemination of Conidiospores of Colletotrichum gloeosporioides, the Anthracnose of Persimmon and the Disease Development
Kwon, Jin-Hyeuk ; Park, Chang-Seuk ;
Research in Plant Disease, volume 10, issue 4, 2004, Pages 272~278
DOI : 10.5423/RPD.2004.10.4.272
The disease development of Anthracnose of sweet persimmon in relation to release of conida of Colletotrichum gloeosporioides were observed in a farmer's field located in Jinju from 1998 to 2002. The conidia started to release from early April and reached maximum in June to late July. The amount of conidia production reduced drastically from early August. The number of conidia trapped was closely related to amount of precipitation at the same period and number of new infections on the emerging branches and young fruits in orchard. The conidia released during the April was not effected to disease occurrence of persimmon tree but the spores produced from inoculum source after early May significantly important to the infection of the pathogen on emerging branch and this infection was directly related to infections on young fruits. Consequently the early infections on the branches brought severe occurrence of Anthracnose in the orchard. Most of the infected fruits were dropped in unripe state. The earlier infection caused the earlier fruit drop. The rate of fruit drop was reached up to 84.1% in August when the disease was occurred severely. Anthracnose of sweet persimmon also occurred in market shelf and storage warehouse. The anthracnose fruits are presumed to be infected while in orchard. Because the symptom formed on the fruit was too tiny to eliminate, the infected fruits were involved in storage boxes and anthracnose gradually developed in storage condition. The rate of diseased fruit observed in Jinju area were 1.2 to 1.6%.
Morphological Features of Coleosporium xanthoxyli and Its Alternate Host in Korea
Lee, S.K. ; Lee, K.H. ; Lee, C.K. ; Kim, D.Y. ; Hwang, J.H. ;
Research in Plant Disease, volume 10, issue 4, 2004, Pages 279~284
DOI : 10.5423/RPD.2004.10.4.279
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.
Relationship between the Production of Fermentational Off-flavor and Presence of Microbial Endophytes in Bloody Watermelon
Choi, Jae-Eul ; Choi, Chun-Hwan ; Ryuk, Jln-Ah ; An, Gil-Hwan ; Hwang, Yong-Soo ;
Research in Plant Disease, volume 10, issue 4, 2004, Pages 285~289
DOI : 10.5423/RPD.2004.10.4.285
The bloody watermelon exhibiting dark red and fermentation off-flavor results in a great economic loss. As an effort to clarify the cause of the bloody watermelon, relationship between the fermentational off-flavor and the presence of endophytic bacteria was studied. The number of endophytes was 2.2-37.0
cfu/g fw (fresh weight) in normal watermelons, compared to 1.26-1.75
cfu/g fw in bloody ones. Seventeen bacteria among 56 isolates from bloody watermelons could induce bloody watermelons. The bacteria responsible for bloody watermelons were mainly Gram negative: aerobic Pseudomonas spp and some anaerobic bacteria. The results in this study strongly suggested that the bloody watermelons were produced by abnormal fermentation and growth of endophytic Gram negative bacteria.
Identification and Ecological Characteristics of Bacterial Blossom Blight Pathogen of Kiwifruit
Shin, Jong-Sup ; Park, Jong-Kyu ; Kim, Gyoung-Hee ; Park, Jae-Young ; Han, Hyo-Shim ; Jung, Jae-Sung ; Hur, Jae-Seoun ; Koh, Young-Jin ;
Research in Plant Disease, volume 10, issue 4, 2004, Pages 290~296
DOI : 10.5423/RPD.2004.10.4.290
Bacterial blossom blight is one of the most important diseases of kiwifruit (Actinidia deliciosa). The disease occurs during flowering in the late May and disease outbreaks associated with rainfall during the flowering season have resulted in a severe reduction in kiwifruit production. The causal organism isolated from diseased blossoms of kiwifruits was identified as Pseudomonas syringae pv, syringae based on the physiological and biochemical characteristics and pathogenicity test. Dead fruit stalks, dead pruned twigs, fallen leaves and soils mainly provided R syringae pv. syringae with overwintering places in the kiwifruit orchards, and the inocula also overwintered on buds, trunks, branches, and twigs on the kiwifruit trees. Among the overwintering places, the incula were detected in the highest frequencies from dead fruit stalks. The population density of P. syringae pv. syringae was speculated to be over
cfu/ml for the bacterial infection, and the optimum temperature for the bacterial growth ranged 20 to
. The highest population density of P. syringae pv. syringae on the overwintering places was detected in May and June when the daily average temperature coincided with the optimum temperature for bacterial growth of P. syringae pv. syringae.
Optimum Spray Program of Preventive Bactericides for the Control of Bacterial Blossom Blight of Kiwifruit
Shin, Jong-Sup ; Park, Jong-Kyu ; Kim, Gyoung-Hee ; Jung, Jae-Sung ; Hur, Jae-Seoun ; Koh, Young-Jin ;
Research in Plant Disease, volume 10, issue 4, 2004, Pages 297~303
DOI : 10.5423/RPD.2004.10.4.297
Bacterial blossom blight of kiwifruit (Actinidia deliciosa) has been mainly controlled by antibiotics. Among 15 candidate chemicals, streptomycin sulfate oxytetracycline WP, streptomycin copper hydroxide WP and oxolinic acid WP were selected as preventive bactericides against bacterial blossom blight of kiwfruit through in vitro and in vivo test. Spray of streptomycin sulfate oxytetracycline WP and streptomycin copper hydroxide WP at flowering period was most effective in controlling bacterial blossom blight of kiwifruit. Among the various combinations of spray times at different spray periods, optimum spray program of the preventive bactericides for the control of bacterial blossom blight of kiwifruit was turned out to be 3 times application with 10 day-interval from early May during the flowering season of kiwifruits.
Cultural Control of Bacterial Blossom Blight Using Trunk Girdling and Rainproof Installation over Kiwifruit Trees
Shin, Jong-Sup ; Park, Jong-Kyu ; Kim, Gyoung-Hee ; Jung, Jae-Sung ; Hur, Jae-Seoun ; Koh, Young-Jin ;
Research in Plant Disease, volume 10, issue 4, 2004, Pages 304~309
DOI : 10.5423/RPD.2004.10.4.304
Girdling of trunk and rainproof installation over kiwifruit (Actinidia deliciosa) trees were turned out to alleviate bacterial blossom blight effectively in kiwifruit orchards. The disease was most effectively prevented by girdling of tree trunks with 20 mm width around April 10 before about 45 days of flowering stage of kiwifruit, but control efficiencies were not affected by height of girdling on trunks above the ground. Use of a transparent polyvinyl film to protect kiwifruit trees from rain was more effective than windbreak net to prevent the disease, irrespective of kinds of rainproof installation. Installation of partial rainproof vinyl cover over kiwifruit trees around March 10 before about 75 days of flowering stage of kiwifruit prevented most of the disease occurrence on kiwifruit. It is expected that girdling of tree trunks and installation of partial rainproof vinyl cover over kiwifruit trees will be practical as environmentally friendly control methods to manage bacterial blossom blight in kiwifruit orchards.
Detection of Pseudomonas syringae pv. actinidiae in Soil on the Basis of PCR Amplification
Han, Hyo-Shim ; Koh, Young-Jin ; Jung, Jae-Sung ;
Research in Plant Disease, volume 10, issue 4, 2004, Pages 310~312
DOI : 10.5423/RPD.2004.10.4.310
Pseudomonas syringae pv. actinidiae is the causative agent of bacterial canker in kiwifruit. A nested PCR detection method that uses primers designed from the cfl gene, involved in production of the phytotoxin coronatine, was applied on soil samples. These primers yielded 665 and 310-bp fragments in consecutive PCR amplification step with DNA from soil inoculated with Korean strain of P. syringae pv. actinidiae. This system was applied to survey soil samples from a kiwifruit orchard destroyed by bacterial canker. A specific 310-bp PCR product was obtained from all six samples of soil tested.
Occurrence and Its Condition of Internal Fruit Rot Caused by Didymella bryoniae in Cucumber
Lee, Sang-Yeob ; Hwang, Soon-Jin ; Lee, Sang-Bum ; Kim, Yong-Ki ;
Research in Plant Disease, volume 10, issue 4, 2004, Pages 313~318
DOI : 10.5423/RPD.2004.10.4.313
Internal fruit rot of cucumber was observed in several locations in Korea. Incidence of the disease reached up to 21.5% and averaged 4.2% in the fields surveyed. The disease started at blossom ends of cucumber fruits. Internal tissues of infected fruit tips showed brown discoloration over 2 cm in length and 2 mm in diameter. Subsequently, the brown discoloration was extended into the carpels, and the surface of the infected fruit tips was rugged. Fungal isolates from the internal tissues of diseased fruits were identified as Didymella bryoniae based on mycological characteristics. Temperature for mycelial growth of isolates ranged
with optimal temperature between
. Similar symptoms were developed in the internal part of the cucumber fruit when conidial suspensions of the isolates were inoculated to the flower of cucumber. Furthermore, Didymella bryoniae isolates from other plant parts of cucumber, watermelon, oriental melon, melon and pumpkin also showed the similar symptoms in the internal part of cucumber fruits by inoculation tests. Temperature range for occurrence of internal fruit rot of cucumber was
with optimal temperature of
Biological Control of Botrytis Leaf Blight of Lily and Botrytis Gray Mold of Cucumber by Ulocladium atrum
Lee, Nam-Young ; Kwon, Eun-Mi ; Kim, Jin-Cheol ; Yu, Seung-Hun ;
Research in Plant Disease, volume 10, issue 4, 2004, Pages 319~323
DOI : 10.5423/RPD.2004.10.4.319
This study was conducted to investigate the effect of U. atrum treatment on control of Botrytis leaf blight of lily and Botrytis gray mold of cucumber, and to evaluate the U. atrum as the biological control agent of Botrytis diseases. The antagonistic isolates CNU 9037 and CNU 9054 isolated from tomato leaves were identified as Ulocladium atrum Preuss based on morphological characteristics. This is the first record of U. atrum in Korea. In bioassays on dead leaves of tomato and cucumber, treatment of U. atrum colonized the dead leaves and suppressed sporulation of Botrytis as compared with the untreated control. The suppression of spoulation of Botrytis on dead leaf segments by U. atrum was higher when U. atrum was treated before Botrytis was treated. The effect of treatments with conidial suspension of U. atrum on leaf blight of lily and gray mold of cucumber caused by Botrytis elliptica and B. cinerea, respectively, was investigated under greenhouse conditions. Spraying U. atrum (
conidia per ml) at intervals of 1 week for three times resulted in a significant reduction of natural infections of lily leaves caused by B. elliptica. Protective value of U. atrum treatment was higher than that of the fungicide (procymidone) treatment. Spraying U. atrum also resulted in a significant reduction of cucumber gray mold caused by B. cinerea. Our results show that U. atrum has a potential for biological control against diseases caused by Botrytis spp, in lily and cucumber.
Occurrence of Sclerotinia Rot of Crisphead Lettuce Caused by Sclerotinia sclerotiorum and Its Pathogenicity
Baek, Jung-Woo ; Kim, Han-Woo ; Kim, Hyun-Ju ; Park, Jong-Young ; Lee, Kwang-Youll ; Lee, Jin-Woo ; Jung, Soon-Je ; Moon, Byung-Ju ;
Research in Plant Disease, volume 10, issue 4, 2004, Pages 324~330
DOI : 10.5423/RPD.2004.10.4.324
This studies were investigated the occurrence of sclerotinia rot at the crisphead lettuce field in Uiryeong-Gun, Gyeongsangnam-Do from January to May in 2003. Average incidence rates of sclerotinia rot on crisphead lettuce was up to 21.9% at the five plastic houses. A total of 140 isolates of Sclerotinia sp. were obtained from diseased leaves of crisphead lettuce. Among them, the fungi YR-1 was isolated, which showed highly virulent on the whole plant. the YR-1 was identified as Sclerotinia sclerotiorum based on the formation, color, shape and size of sclerotium and apothecium. For the pathogenicity test, the most suitable inoculum quantity of YR-1 strain was selected as the triturated mycelial suspension of
=0.8, 40 ml showing disease incidence of 94%, and the symptom showed as same as at the fields, the leaves and stem had rotten and developed white downy mycelial at the diseased lesion on the leaves and stems, and produced black and irregular sclerotinia. This is the first report on the pathogenicity test using by triturated mycelial suspension-inoculum of the pathogen for the sclerotinia rot of crisphead lettuce.
Isolation and Identification of Antagonistic Bacterium Active against Sclerotinia sclerotioum Causing Sclerotinia Rot on Crisphead Lettuce
Kim, Han-Woo ; Lee, Kwang-Youll ; Baek, Jung-Woo ; Kim, Hyun-Ju ; Park, Jong-Young ; Lee, Jin-Woo ; Jung, Soon-Je ; Moon, Byung-Ju ;
Research in Plant Disease, volume 10, issue 4, 2004, Pages 331~336
DOI : 10.5423/RPD.2004.10.4.331
The fungus genus Sclerotinia contains a number of important plant pathogens. Vegetable growers in our country are probably most familiar with Sclerotinia sclerotiorum, the causes of sclerotinia rot on crisphead lettuce. S. sclerotiorum has a wide host range which can include lettuce as well as crops such as broccoli, cabbage, carrots, celery, beans, peppers, potatoes, stocks, and tomato. Some fungicides, including benomyl, are effective in some crops, but not all. So, we isolated a antagonistic bacteria that are active on sclerotinia rot caused by S. sclerotiorum and that can be used to control it. About 702 strains had been isolated from soil around plant roots in the field. Ten strains showed strong antifungal activity against S. sclerotiorum. In pot test for antagonistic activity, A-7 strain showed high control value against the pathogen when compared with others. The strain was, therefore, selected as a biocontrol candidate against sclerotinia rot and its biochemical properties and 16S rDNA sequence was analyzed. The A-7 strain was highly related to Bacillus subtilis and B. amyloliquefaciens. To confirm precise identification, we had performed gyr A gene sequences analysis. Its sequence had 96% similarity with B. amyloliquefaciens. Consequently, the isolate was identified as B. amyloliquefaciens A-7.
Gray Mold of Zinnia elegans Caused by Botrytis cinerea in Korea
Kwon, Jin-Hyeuk ; Son, Kyung-Ae ; Jeong, Seon-Gi ; Park, Chang-Seuk ;
Research in Plant Disease, volume 10, issue 4, 2004, Pages 337~340
DOI : 10.5423/RPD.2004.10.4.337
In April of 2003, the gray mold disease caused by Botrytis cinerea was occured in zinnia seedlings grown in greenhouse at Gyeongsangnam-do Agricultural Research and Extension Services, and farmer's nursery. The symptoms of infected plants were started with water-soaking lesions in flower bud, leaves and stems. The lesions gradually expanded and infected plants became withered and discolored to gray or dark from the tip. The conidia and mycelia of the pathogen were appeared on flowers, leaves and stem. The conidia were gray, 1-celled, mostly ellipsoid or ovoid in shape and were 5
in size. Conidiophores were 12
in size. The pathogenic fungi formed sclerotia abundantly on potato dextrose agar. The optimum temperature for sclerotial formation was
. Pathogenicity of the causal organism was proved according to Koch's postulate. The causal organism was identified as Botrytis cinerea Persoon: Fries based on mycological characteristics. This is the first report on gray mold of Zinnia elegans caused by Botrytis cinerea in Korea.
Occurrence Tendency and Decrease of Fruits Brix According to Increasing Grapevine Leaf Spot Disease Caused by Pseudocercospora vitis
Park, Jong-Han ; Han, Kyung-Sook ; Lee, Jung-Sup ; Seo, Sang-Tae ; Jang, Han-Ik ; Kim, Heung-Tae ;
Research in Plant Disease, volume 10, issue 4, 2004, Pages 341~344
DOI : 10.5423/RPD.2004.10.4.341
Grapevine leaf spot caused by Pseudocercospora vitis also called leaf Isariopsis spot which is one of the most important disease in Korea. Spots on the leaves are irregular to angular. They are brown, measure 2
20 mm in diameter. Campbell Early, the major grape cultivar in Korea, is very susceptible to this disease. Leaf spot of grape is outbreak about 95% in ratio of diseased leaves according to the areas and management state of orchards in Korea. The diseased grapevines have some difficulty in raise of the trees by early defoliation and decrease the quality of fruits by disadvantage of assimilation products accumulation. Severe outbreak of the grapevine leaf spot is one of the factors that decrease of sugar content of the fruits about 20%. The strong negative correlation was observed between disease increase of grapevine and decrease of sugar content of the fruits. The correlation equation between relative sugar content of fruits and accumulated percentage of diseased leaves was Y = 0.0009
- 0.3717X + 116.45(
Pink Rot of Palms Caused by Gliocladium vermoseni
Han, Kyung-Sook ; Park, Jong-Han ; Lee, Jung-Sup ; Seo, Sang-Tae ; Jang, Han-Ik ;
Research in Plant Disease, volume 10, issue 4, 2004, Pages 345~348
DOI : 10.5423/RPD.2004.10.4.345
Pink rot of Palm was occurred at Yeuju area in 2001 and 2003. Infected plants showed rotting at the leaf-stock bases and killing of the terminal bud. The first symptoms are dark brown necrotic areas on the stem. Bases of infected frond may be covered with pink spores and the spots produced oozing gum pockets. Oozing lesions occur on the stems, and leaves turn brown and droop. The causal agent were isolated from salmon-pink spores sporulating on the leaf sheaths and necrotic stem tissues. Pathogen were isolated from freshly infected tissues were identified as Gliocladium vermoseni based on mycological characteristics. Fungus were grown plenty on PDA culture. Temperature for mycelial grown was tested at 5 to
and optimal temperature was
and was not nearly grew at temperature above
. Artificial pathogenicity were tested on 9 species of Palm family in the wound inoculation and symptoms showed similar to those observed in the field. This is the first report on pink rot of palm in Korea.
Inhibitory Effect of Garlic Extracts on Some Plant Pathogens
Seo, Sang-Tae ; Lee, Jung-Sup ; Park, Jong-Han ; Han, Kyoung-Suk ; Jang, Han-Ik ;
Research in Plant Disease, volume 10, issue 4, 2004, Pages 349~352
DOI : 10.5423/RPD.2004.10.4.349
Antimicrobial activity of garlic extracts of four local cultivars (Namdo, Goheung, Danyang and garlic imported from China) against several plant pathogenic bacteria and fungi was investigated. The garlic extracts exhibited marked in vitro antimicrobial activities against the Gram-positive and -negative bacteria as well as fungal pathogens. Of the four cultivars, two cultivars (Namdo and garlic imported from China) showed relatively good antimicrobial activities. Gram-positive bacteria, Clavibater michiganensis was most sensitive, whereas Burkholderia cepacia was the strong resistant towards garlic extracts. Results from the planta bioassays under greenhouse conditions indicated that garlic extracts significantly reduced the cucumber powdery mildew disease showing control value 59.7-61.9% compared with the nontreated controls.