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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 16, Issue 3 - Dec 2010
Volume 16, Issue 2 - Aug 2010
Volume 16, Issue 1 - Apr 2010
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Genotypic Characterization of Oak Wilt Pathogen Raffaelea quercus-mongolicae and R. quercivora Strains
Seo, Sang-Tae ; Kim, Kyung-Hee ; Lee, Sang-Hyun ; Kwon, Yong-Nam ; Shin, Chang-Hoon ; Kim, Hye-Jeong ; Lee, Sang-Yong ;
Research in Plant Disease, volume 16, issue 3, 2010, Pages 219~223
DOI : 10.5423/RPD.2010.16.3.219
Recently, the oak wilt diseases especially on Quercus mongolica, have been increasing in various districts of Korea. A collection of 38 strains of the oak wilt pathogen Raffaelea qeurcus-mongolicae and R. quecivora isolated from Quercus spp. in Korea and Japan was characterized by
-tubulin gene sequence and randomly amplified polymorphic DNA (RAPD) analysis. In cluster analysis based on
-tubulin gene sequence the strains were divided into 4 clusters, of which clusters 2 and 4 were composed of Japanese strains except for one Korean strain. RAPD analysis showed that they were also effectively differentiated by a strong RAPD fragments. On the basis of the two genetic analysis, significant differences were detected between Korean strains and Japanese strains.
Genetic Diversity and Pathotypes of Xanthomonas orzyae pv. oryzae Isolated in Korea
Oh, Chang-Sik ; Roh, Eun-Jung ; Lee, Seung-Don ; La, Dong-Soo ; Heu, Sung-Gi ;
Research in Plant Disease, volume 16, issue 3, 2010, Pages 224~231
DOI : 10.5423/RPD.2010.16.3.224
Xanthomonas oryzae pv. oryzae, causal agent of bacterial leaf blight (BLB) of rice, had been collected and identified using Biolog and fatty acid analysis. Epidemics of BLB had been occurred all the times at several rice cultivating areas in Korea in 1999-2004. Most X. oryzae pv. oryzae isolated in 1999 and 2002 belonged to Korean race K1, but more than 50% of the pathogen isolated in 2003 belonged to Korean race K3. Especially, most pathogens isolated in Jeonnam and Joenbuk provinces belonged to Korean race K3. Inoculation test of near isogenic lines (NIL) of rice carrying single resistance genes against BLB showed that many isolates belonging to Korean race 1 reacted differently to diverse resistant monogenic lines of rice. Southern blot analysis also showed that the bacterial pathogens belonged to the same race had different numbers of avirulence genes. This results suggested that each Korean race type may respond to many resistance genes of rice. All the K3 races isolated in Jeonnam and Joenbuk provinces were able to cause disease on Xa3 monogenic lines of rice. Since most rice cultivars cultivated in Jeonnam and Jeonbuk were carrying Xa3 resistance genes, the bacterial pathogens isolated in Jeonnam and Jeonbuk were likely to develop to adapt to Xa3 resistance gene. Together with avirulence gene patterns of the bacterial isolates and the results of disease reaction of monogenic lines of rice to them, Korean X. oryzae pv. oryzae was classified into 19 pathotypes. This newly classified pathotypes should help the breeding of new resistance rice cultivars in Korea.
Occurrence and Symptoms of Tomato spotted wilt virus on Egg Plant, Whole Radish and Sugar Loaf in Korea
Cho, Jeom-Deog ; Kim, Jin-Young ; Kim, Jeong-Soo ; Choi, Hong-Soo ; Choi, Gug-Seoun ;
Research in Plant Disease, volume 16, issue 3, 2010, Pages 232~237
DOI : 10.5423/RPD.2010.16.3.232
Tomato spotted wilt virus (TSWV) was occurred on the three vegetables of egg plant (Solanum melongena), whole radish (Raphanus acanthiformis) and sugar loaf (Cichorium intybus) at Anyang area infested with TSWV. Whole radish was produced the symptoms of necrotic spots on the leaves, and necrosis and malformation on the roots by TSWV. Egg plant was induced the symptoms of typical multiple ring spots on the leaves and necrotic rings on the fruits. Sugar loaf was infected severely with the typical symptoms of ring spots on the leaves and stunt. The three isolates of TSWV could infect locally on the indicator plants of Chenopodium amaranticolor, C. quinoa and Nicotiana debney, and systemically on N. glutinosa, N. benthamiana and Datura stramonium. Two TSWV isolates from egg plant and sugar loaf were very similar in virulence. However, the virulence of TSWV from whole radish was very different as local infection on 5 Nicotiana species including N. tabacum `Xanthi NC`.
Identification of a New Potyvirus, Keunjorong mosaic virus in Cynanchum wilfordii and C. auriculatum
Lee, Joo-Hee ; Park, Seok-Jin ; Nam, Moon ; Kim, Min-Ja ; Lee, Jae-Bong ; Sohn, Hyoung-Rac ; Choi, Hong-Soo ; Kim, Jeong-Soo ; Lee, Jun-Seong ; Moon, Jae-Sun ; Lee, Su-Heon ;
Research in Plant Disease, volume 16, issue 3, 2010, Pages 238~246
DOI : 10.5423/RPD.2010.16.3.238
In 2006 fall, a preliminary survey of viruses in two important medicinal plants, Cynanchum wilfordii and C. auriculatum, was conducted on the experimental fields at the Agricultural Research and Extension Services of Chungbuk province in Korea. On each experimental fields, percentage of virus infection was ranged from 20 to 80%, and especially an average of disease incidence propagated by roots was twice higher than that by seeds. The various symptoms were observed in Cynanchum spp. plants, such as mosaic, mottle, necrosis, yellowing, chlorotic spot and malformation etc. In electron microscopic examination of crude sap extracts, filamentous rod particles with 390-730 nm were observed in most samples. The virus particles were purified from the leaves of C. wilfordii with typical mosaic symptom, and the viral RNA was extracted from this sample containing 430-845 nm long filamentous rod. To identify the viruses, reverse transcription followed by PCR with random primers was carried out. The putative sequences of P3 and coat protein of potyvirus were obtained. From a BLAST of the two sequences, they showed 26-38% and 62-72% identities to potyviruses, respectively. In SDS-PAGE analysis, the subunit of coat protein was approximately 30.3 kDa, close to the coat protein of potyvirus. In bioassay with 21 species in 7 families, Chenopodium quinoa showed local lesion on inoculated leave and chlorotic spot on upper leave, but the others were not infected. RT-PCR detection using specific primer of C. wilfordii and C. auriculatum samples, all of 24 samples with virus symptom was positive, and five out of seven samples without virus symptom were also positive. On the basis of these data, the virus could be considered as a new member of potyvirus. We suggested that the name of the virus was Keunjorong mosaic virus (KjMV) after the common Korean name of C. wilfordii.
Occurrence of Apple Scar Skin viroid and Relative Quantity Analysis Using Real-time RT-PCR
Kim, Dae-Hyun ; Kim, Hyun-Ran ; Heo, Seong ; Kim, Se-Hee ; Kim, Min-A ; Shin, Il-Sheob ; Kim, Jeong-Hee ; Cho, Kang-Hee ; Hwang, Jeong-Hwan ;
Research in Plant Disease, volume 16, issue 3, 2010, Pages 247~253
DOI : 10.5423/RPD.2010.16.3.247
Apple scar skin viroid (ASSVd) is one of the smallest viral pathogens infecting fruits, especially apple, and causes a significant damage to fruit trees. ASSVd usually induced the skin-dapple ring symptoms, but in `Fuji` varieties, corked spot were occurred on the fruit skin in 2009. This new symptom will be of great helpful to diagnosis ASSVd in sight. ASSVd was surveyed in apple and pear from 2009 to 2010 in Korea, and ASSVd was identified in 20 out of 1,193 trees. The infection rate was 1.7%. To screen the infectivity of ASSVd among apple cultivars, real-time RT-PCR was applied followed by designing of ASSVd specific primers based on highly conserved regions of several ASSVd isolates including Korean isolate. NADH dehydrogenase subunit 5 (nad 5) gene, which is mRNA of the mitochondrial gene, was used for internal control. In this study, ASSVd infected apples were classified into 12 groups depending on different symptoms and symptom severity (scaring, rusting or malformation). Taken together, this study suggested that real-time PCR analysis was more sensitive to detect the low copy of ASSVd on early viroid infected apple skins than regular RT-PCR method.
Some Characteristics of Melon necrotic spot virus-Me and Resistance Screen to the Virus in Melon Cultivars
Choi, Gug-Seoun ; Cho, Jeom-Deog ; Chung, Bong-Nam ; Cho, In-Sook ; Kwon, Soon-Bae ;
Research in Plant Disease, volume 16, issue 3, 2010, Pages 254~258
DOI : 10.5423/RPD.2010.16.3.254
Melon necrotic spot virus (MNSV) is a very destructive disease to melon (Cucumis melo) plants. A MNSV was isolated from melon leaf showing necrotic spot symptoms at the plastic house in Naju, Korea in 2009. The isolate, designated as MNSV-Me, was identified and characterized by biological responses on several host plants, immuno captured RT-PCR and partial nucleotide sequencings of the genome. To evaluate MNSV-Me resistance in melon, thirty-five melon cultivars were mechanically inoculated on the cotyledon of the seedlings with the virus. MNSV-Me produced necrotic spots on the inoculated leaves of the all melon cultivars tested. Twenty-five cultivars were susceptible to the virus and they showed systemic necrotic spots on the leaves and/or necrosis longer than 3 cm in length on the stems within about forty days after inoculation. Five cultivars gave moderate resistance, no symptoms on the upper leaves but necrosis on the stem shorter than 3 cm in length. In an evaluation of MNSV-Me resistance in melon cultivars, `Elstitan`, `Elsluxery`, `Betalichihage`, `Betalichi` and `Womderfulhagae 1st` were found to have resistance by showing only faint necrosis on their stems.
Inhibitory Effects of PLM-WE1 Formulated from Extract of Phellinus linteus Mycelium against Plant Viruses Infection and Identification of Active Compound
Kwon, Soon-Bae ; Bae, Seon-Hwa ; Choi, Jang-Kyung ; Lee, Sang-Yong ; Kim, Byung-Sup ; Kwon, Yong-Soo ;
Research in Plant Disease, volume 16, issue 3, 2010, Pages 259~265
DOI : 10.5423/RPD.2010.16.3.259
Pepper mild mosaic virus(PMMoV) and Cucumber mosaic virus (CMV) are important pathogens in various vegetable crops worldwide. We have found that hot water extract of Phellinus linteus mycelium strongly inhibit PMMoV and CMV infection. Based on these results, the inhibitor named as `PLM-WE1` formulated from extract of Phellinus linteus mycelium was tested for its inhibitory effects on PMMoV and CMV infection to each local lesion host plant (Nicotiana glutinosa: PMMoV, Chenopodium amaranticolor: CMV). Pretreatment effect of PLM-WE1 against infections of each virus (PMMoV and CMV) to local host plant was measured to be 99.2% to PMMoV and 80.3% to CMV, and its permeability effect was measured to be 45.0% to PMMoV and 41.9% to CMV. Duration of inhibitory activity of PLM-WE1 against PMMoV infection on N. glutinosa was maintained for 3 days at 75% inhibition level and CMV infection on C. amaranticolor maintained for 3 days at 62% inhibition level. Inhibitory effects on systemic host plants of PLM-WE1 were measured to be 75~85% to PMMoV and 75% to CMV. Under electron microscope, PMMoV particles were not denatured or aggregated by mixing PLM-WE1. It is suggested that the mode of action of PLM-WE1 differ from that of inactivation due to the aggregation of viruses. The methanol extract of P. linteus mycelium was sequentially partitioned with haxane, ethyl acetate, BuOH and
fraction was showed high activity than the other fractions. The active compound was isolated with a partial acid hydrolysis, fractional precipitation with ethanol. The inhibitory effect of the precipitate isolated from 70% ethanol fraction was 99.1% to PMMoV and 88.0% to CMV. The structure of isolated compound was determined by
-NMR. This compound was identified as a polysaccharide consisting alpha or beta-glucan.
Selection of Bactericides for Controlling Soybean Bacterial Pustule
Hong, Sung-Jun ; Kim, Yong-Ki ; Jee, Hyeong-Jin ; Lee, Bong-Choon ; Yoon, Young-Nam ; Park, Sung-Tae ;
Research in Plant Disease, volume 16, issue 3, 2010, Pages 266~273
DOI : 10.5423/RPD.2010.16.3.266
Bacterial pustule of soybean (Glycines max) caused by Xanthomonas axonopodis pv. glycines is one of the most prevalent bacterial diseases of soybean. This bacterium shows strong pathogenicity to the plants and distributes throughout Korea. However, no good control measures including bactericides and resistant cultivars are available to control the disease in Korea. Therefore, this study was conducted to develop chemical control method against soybean bacterial pustule. The present study was undertaken to find out the growth inhibitory effect bactericides (8 antibiotics, 2 copper compounds, quinoline, 18 agro-chemicals) on bacterial pustule pathogen. Antibiotics test showed that tetracycline and streptomycin sulfate significantly suppressed the growth of bacterial pustule pathogen. Also, application of oxolinic acid was found to be effective for pathogen inhibition. However, vancomycin, polymyxin B sulfate and copper compounds did not show the positive suppressive effect on growth of the pathogen. Among the eighteen agro-chemicals, streptomycin sulfate + oxytetracyclin (18.8 + 1.5%) WP, oxytetracycline (17%) WP and oxolinic acid (20%) WP were found to be effective for the inhibition of the pathogen in vitro. The selected 5 agro-chemicals were also applied on soybean in field and their control effects against the soybean bacterial pustule were tested. The foliar application of streptomycin sulfate + oytetracyclin WP and oxytetracycline WP on the naturally infected soybean (Taekwangkong) showed high control value (above 70%). Therefore, it is concluded that the bactericides used in this study showed strong inhibitory effect to soybean bacterial pustule and they can be recommend to farmers to control the disease.
Changes of Mating Type Distribution and Fungicide-resistance of Phytophthora infestans Collected from Gangwon Province
Park, Kyeong-Hun ; Ryu, Kyoung-Yul ; Yun, Jeong-Chul ; Jeong, Kyu-Sik ; Kim, Jeom-Soon ; Kwon, Min ; Kim, Byung-Sup ; Cha, Byeong-Jin ;
Research in Plant Disease, volume 16, issue 3, 2010, Pages 274~278
DOI : 10.5423/RPD.2010.16.3.274
Potato late blight caused by Phytophthora infestans was the most constrain disease at potato cultivation areas. The mating type distribution and fungicides response of P. infestans were investigated to elucidate the changes of pathogen from Gangwon province. On the fungal isolates in 2006, 58.7% were A1 mating type and 41.3% were A2 mating type. In 2007, A1 mating type isolates increased to 93.3% and A2 mating type isolates were collected from Jinbu areas as much as 6.7%. About 234 isolates analysed for metalaxyl response, the results was resistance 73.7%, intermediate 18.8% and sensitive 7.5% in 2006. And it was resistance 59.4%, intermediate 4.0% and sensitive 36.6% in 2007. It meant that mating type distribution and fungicide response were very different over the collection sites. Minimal inhibition concentration (MIC) of dimethomorph examined with 126 isolates in 2006 and 106 isolates in 2007. MIC over
was 56.3% in 2006 and it was 3.8% in 2007. The average
value of P. infestans was
in 2006, but it decreased to
in 2007. Fungicides response and pathogenesis of P. infestans should be monitored continuously to enhance the chemical efficacy at potato fields.
Convenient Screening Method of Chinese Cabbage for Resistance to Plasmodiophora brassicae Using Soil-Drenching Inoculation
Jo, Su-Jung ; Jang, Kyoung-Soo ; Choi, Yong-Ho ; Kim, Jin-Cheol ; Choi, Gyung-Ja ;
Research in Plant Disease, volume 16, issue 3, 2010, Pages 279~284
DOI : 10.5423/RPD.2010.16.3.279
Clubroot caused by Plasmodiophora brassicae is a widespread disease that causes serious problems in many brassica growing areas. To establish more simple and reliable clubroot screening method of Chinese cabbage to P. brassicae using soil-drenching inoculation, the development of clubroot on Chinese cabbage according to several conditions such as soil type, inoculum concentration of P. brassicae GN-1 (race 9), plant growth stage and incubation period was studied. In a commercial horticulture nursery media soil (CNS), disease severity of the seedling according to inoculum concentration increased in a dose-dependent manner, but did not in mixture of CNS and upland soil (1:1, v/v). To facilitate and acquire precise result of resistance screening of Chinese cabbage to clubroot, 10-day-old seedlings should be inoculated by drenching the spore suspension of P. brassicae to give inoculum density of
spores/pot. To develop the disease, the inoculated seedlings were incubated in a growth chamber at
for 3 days, and then cultivated in a greenhouse (
) for five weeks. Under the optimum conditions, 25 clubroot-resistant (CR) and 3 clubroot-susceptible (CS) cultivars were tested for resistance to P. brassicae. All CR cultivars showed very clear resistance response, on the other hand all CS cultivars severly infected with the pathogen. The results suggest that this method is efficient screening method of Chinese cabbage for resistance to clubroot disease.
Yield Loss Assessment and Economic Thresholds of Squash Powdery Mildew Caused by Sphaerotheca fuliginea
Moon, Youn-Gi ; Choi, Jun-Keun ; Kang, An-Seok ;
Research in Plant Disease, volume 16, issue 3, 2010, Pages 285~289
DOI : 10.5423/RPD.2010.16.3.285
The experiments were carried out in fields for two years from 2008 to assess yield losses of squash due to powdery mildew caused by Sphaerotheca fuliginea and to determine its economic thresholds. Powdery mildew disease was first observed in late June, about 50 days after field-transplanting, progressed rapidly during late July to early August, and began to reduce from late August. Powdery mildew severity was negatively correlated with squash yields. A positive correlation was observed between fruit weight and % marketable fruits. A simple linear regression model was obtained as Y
Screening of Tomato Cultivars Resistant to Bacterial Canker by Seedling Test
Han, You-Kyoung ; Han, Kyung-Sook ; Lee, Seong-Chan ; Kim, Hyung-Hwan ; Kim, Su ; Kim, Dong-Hwi ;
Research in Plant Disease, volume 16, issue 3, 2010, Pages 290~293
DOI : 10.5423/RPD.2010.16.3.290
Bacterial canker, caused by Clavibacter michiganensis subsp. michiganensis, is a very damaging disease to tomato (Lycopersicon esculentum) farm in Korea. It infects tomato, spreads through the xylem and causes bacterial wilt and canker. Selection of resistant cultivar is the best way to prevent or reduce the occurrence of the disease. Thirty-nine tomato cultivars, twenty-one cherry tomato cultivars and thirteen rootstock tomato cultivars were inoculated with Clavibacter michiganensis subsp. michiganensis, to evaluate tomato cultivarspecific resistance against bacterial canker. In the evaluation of 73 major commercial cultivars, `Sunmyung`, `Sweet`, `Akiko`, `Dadaki`, `Match`, `Magnet`, `Friend`, and `Greenpower` were found to have a high level of resistance to bacterial canker of tomatoes.
Screening of Tomato Cultivars Resistant to Root-knot Nematode, Meloidogyne incognita
Kim, Hyeong-Hwan ; Cho, Myoung-Rae ; Kang, Taek-Joon ; Jung, Jae-A ; Han, You-Kyoung ;
Research in Plant Disease, volume 16, issue 3, 2010, Pages 294~298
DOI : 10.5423/RPD.2010.16.3.294
Thirty-two tomato cultivars, eleven cherry tomato cultivars and eight rootstock tomato cultivars were inoculated with Meloidogyne incognita, to evaluate tomato cultivars for resistance against root-knot nematodes. One tomato cultivar, Homerunking was proved to be resistant while eight cultivars such as Regendsummer, Regend, Sunmyung, Pinktop, Top3, Delice, Tasha and Lilyance were moderately resistant to the root-knot nematodes. Five cherry tomato cultivars (Tenten, Desert, Redstar, Veryking and Arigatto) showed moderate resistance and one cultivar (Redcherry) was resistant to root-knot nematodes. In eight rootstock tomato cultivars, two cultivars (Bukinghagae, Special) were resistant and five cultivars (B-blocking, Solution, Dongbanja and Greenpower) were moderate.
Improbability of Root Infection by the Pine Wood Nematode in Sawdust Discharged from Chain Saw Lumbering of Infected Trees
Lee, Seung-Kyu ; Park, Joo-Young ; Lee, Chong-Kyu ; Whang, Jin-Hyun ; Moon, Il-Sung ; Cheon, Hyang-Mi ; Heo, He-Soon ;
Research in Plant Disease, volume 16, issue 3, 2010, Pages 299~305
DOI : 10.5423/RPD.2010.16.3.299
Objective of this study is to examine whether pine wood nematode (PWN: Bursaphelenchus xylophilus) in the sawdust discharged from infected trees cause pine wood disease or not. For this, survival time of PWN in soil was examined in which soil moisture was controlled as 15%, 22.5%, and 30% in volume ratio, respectively. The pathogenicity tests were conducted under greenhouse and field conditions. Survival time of PWN in soil was about three days in the saturated (about soil moisture of 23% in volume ratio) and dark condition between 25 and
of room temperature. None of potted seedlings with non-wounded roots was infected by PWN in sawdust. In field, pine wood disease was not occur in any pine trees. These results indicated that PWN discharged on soil when the infected trees were cut by chain saw can not cause pine wood disease.
Natural Occurrence of Fusarium Mycotoxins in Field-collected Maize and Rice in Korea in 2009
Lee, Seung-Ho ; Son, Seung-Wan ; Nam, Young-Ju ; Shin, Jean-Young ; Lee, Soo-Hyung ; Kim, Mi-Ja ; Yun, Jong-Chul ; Ryu, Jae-Gee ; Lee, Theresa ;
Research in Plant Disease, volume 16, issue 3, 2010, Pages 306~311
DOI : 10.5423/RPD.2010.16.3.306
To detect Fusarium mycotoxins, grain samples were collected from 32 rice fields all over the country and from 19 maize fields in eastern and midland provinces in Korea in 2009. Maize contamination with Fusarium species (54.9%) was higher than in rice (8.2%). Using Fusarium species specific PCR primer sets (Fg16 and VERT), 58 and 354 of total 506 isolates from maize samples were putatively identified as F. graminearum (11.5%) and F. verticillioides (70.0%), respectively. From rice samples, 276 of 315 isolates (87.8%) were putatively identified as F. graminearum but F. verticillioides was not identified. LC or LC-MS analysis of the samples revealed that fumonisin was the most commonly detected mycotoxin in maize samples but its level was below the regulation limit. Only two maize samples were contaminated with deoxynivalenol and zearalenone at the levels above the regulation limit. In rice samples, contamination with zearalenone was common but the levels were below the regulation limit. This study showed that most of the Korean maize and rice samples collected in 2009 were contaminated with Fusarium mycotoxins but the levels were below the Korean regulations for deoxynivalenol, fumonisin and zearalenone.
Selection of a Susceptible Line (Susceptible to Pectobacterium 1, Atstp1) to Soft-rot Disease in T-DNA Insertion Mutants Pool of Arabidopsis
Choi, Chang-Hyun ; Kim, Min-Gab ; Ahn, Il-Pyung ; Park, Sang-Ryeol ; Bae, Shin-Chul ; Hwang, Duk-Ju ;
Research in Plant Disease, volume 16, issue 3, 2010, Pages 312~315
DOI : 10.5423/RPD.2010.16.3.312
Pectobacterium carotovorum subsp. carotovorum (Pcc) causes soft rot disease in various plants. Although many studies about Pcc have been going on, little is known yet about the defense genes from plants. To identify defense associated genes in response to Pcc, we screened about 20 thousand Arabidopsis T-DNA knock out lines by inoculation with Pcc. We obtained a line (Atspt1) showing more susceptible symptom compared to WT (Col-0) on 1 day after the inoculation of Pcc on leaves of Arabidopsis with toothpicks. In this study, we optimized the system to select resistant and susceptible lines to Pcc from T-DNA inserted pool of Arabidopsis and expect the system and Atspt1 might be used for molecular breeding to produce resistant vegetables against Pcc.
Occurrence of Gray Mold on Yacon Caused by Botrytis cinerea
Kim, Jeom-Soon ; Lee, Young-Gyu ; Kim, Su-Jeong ; Hong, Sung-Kee ; Choi, Hyo-Won ;
Research in Plant Disease, volume 16, issue 3, 2010, Pages 316~319
DOI : 10.5423/RPD.2010.16.3.316
The gray mold disease occurred on tuberous roots of yacon in storage facilities in Gangneung, Korea, in March 2010. Symptoms typically appeared as in the form of dark brown discoloration on the surface of tuberous roots and water-soaked brown lesions in cross sections of the affected portions. A total of five isolates of Botrytis sp. were obtained from the symptomatic portions. All isolates on potato-dextrose agar (PDA) produced abundant conidia which were pale brown, one-celled, mostly ellipsoid or ovoid in shape and
in size. Large numbers of round to irregular, smooth, black, hard sclerotia were produced on PDA over time. The optimal temperature for mycelial growth and sclerotia formation of the fungal isolates was
. On the basis of morphological and cultural characteristics, all the fungal isolates were identified as Botrytis cinerea. Pathogenicity test on host plants showed that the fungus could infect not only tuberous roots but also leaves and petioles of yacon. This is the first report on gray mold of yacon (Smallanthus sonchifolius) caused by Botrytis cinerea in Korea.
Sclerotium blight of Neofinetia falcata Caused by Sclerotium rolfsii in Korea
Han, Kyung-Sook ; Lee, Seong-Chan ; Han, You-Kyoung ; Kim, Su ; Kim, Dong-Hwi ;
Research in Plant Disease, volume 16, issue 3, 2010, Pages 320~322
DOI : 10.5423/RPD.2010.16.3.320
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
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.
Occurrence of Stem Rot of Sunflower (Helianthus annuus) Caused by Sclerotium rolfsii
Kwon, Jin-Hyeuk ;
Research in Plant Disease, volume 16, issue 3, 2010, Pages 323~325
DOI : 10.5423/RPD.2010.16.3.323
The stem rot of sunflower (Helianthus annuus) occurred sporadically in the experimental field of Gyeongsangnam-do Agricultural Research and Extension Services, on September, 2009. The infected plants were wilted and water-soaked brown spots were formed on the stem, than infected stems were mostly died. White mycelial mats were spread over lesions, and then sclerotia were formed on stem and near soil line. The sclerotia were globoid in shape, 1~3 mm in size and white to brown in color. The optimum temperature for mycelial growth and sclerotia formation on PDA was
and the hyphal width was
. The typical clamp connections were observed in the hyphae of the pathogenic fungus. On the basis of mycological characteristics and pathogenicity to host plants, this fungus was identified as Sclerotium rolfsii. This is the first report on the stem rot of sunflower by S. rolfsii in Korea.
Occurrence of Pome Fruit Viruses on Pear Trees (Pyrus pyrifolia) in Korea
Cho, In-Sook ; Kim, Dae-Huyn ; Kim, Hyun-Ran ; Chung, Bong-Nam ; Cho, Jeom-Doeg ; Choi, Gug-Seoun ;
Research in Plant Disease, volume 16, issue 3, 2010, Pages 326~330
DOI : 10.5423/RPD.2010.16.3.326
Three pome fruit viruses, Apple chlorotic leaf spot virus (ACLSV), Apple stem grooving virus (ASPV) and Apple stem pitting virus (ASGV) were detected in pear trees (Pyrus pyrifolia) using double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) in Ansung, Naju and Ulsan provinces of Korea. Infection rate of three viruses was 35.2% from 452 leaf samples of the three cultivars of pear trees. Also, each of three viruses was detected by reverse transcription polymerase chain reaction (RT-PCR) for a limited number of samples. Infection rate of three viruses was 86.3% from 233 leaf samples of the three pear cultivars. The virus infection rates by RT-PCR were much higher than ELISA. ASGV was prevailing on pear with 74.2%, whereas ASPV and ACLSV were found in 34.8% and 0.4% of tested samples, respectively. Symptoms caused by ASGV showed black spots of infected Niitaka cultivar leaves. The ACLSV, ASPV and ASGV isolates showed 83~94% sequence identity at a nucleotide level to other pome fruit virus isolates when analyzed by NCBI BLAST. Pome fruit viruses occurring in pear were ACLSV, ASPV and ASGV. This is the first report of pear trees infected ASPV in Korea.
Chemical Control of Mosses in Container Nursery
Kim, Jong-Jin ; Lee, Kyung-Jae ; Song, Ki-Sun ; Cha, Young-Geun ; Choi, Kyu-Seong ; Chung, Young-Suk ; Lee, Jong-Hwa ; Yoon, Taek-Seong ;
Research in Plant Disease, volume 16, issue 3, 2010, Pages 331~335
DOI : 10.5423/RPD.2010.16.3.331
The purpose of this study was to develop a method to effectively control mosses that are generated in container. To meet the goals, 6 kinds of chemical agents at different concentrations were applied to the container containing seedlings of Pinus densiflora with growing liverwort (Marchantia polymorpha) and Chamaecyparis obtusa with growing haircap moss (Polytrichum commune). It was found that quinoclamine was the most effective chemical agent to control mosses. Quinoclamine was effective in controlling liverwort (100% controlled) and haircap moss (95.5% controlled) at its concentration of 0.9 g/l. Next to quinoclamine, it was found that haircap moss and liverwort was effectively controlled by pyroligneous liquid which was followed by flumioxazin and oxyfluorfen. Seedling damages were observed in both two species treated with higher concentration of flumioxazin and oxyfluorfen.