• Plant Resources
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• v.3 no.3
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• pp.173-178
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• 2000

This test checked jujube witches'-broom disease, sumac witches'-broom disease, paulonia witches'- broom disease, and mulberry dwarf disease whether or not they were infected by phytoplasma, using universal and specific primers. Upon treatment of DNA amplified by PCR of phytoplasma with Alu I , Hpa II and Sat I restricted enzymes, distinction of phytoplasmas was possible. Particularly, phytoplasma of each host was distinguishable by treatment of Hpa II restricted enzyme. Meanwhile, analysis of restricted enzymes of jujube witches'-broom disease showed a higher infectivity of phytoplasmas of two origins. There were a lot of relations between jujube witches'-broom disease and sumac witches'-broom disease, and between paulonia witches'-broom disease and mulberry dwarf disease.

• Research in Plant Disease
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• v.7 no.2
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• pp.116-119
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• 2001

Witches' broom symptoms were firstly found on tubers of Solanum tuberosum cv, Deijima, showing dense growth of spindly sprouts in Cheju province, Korea. Plantlets from the diseased plants also produced the typical witches' broom symptoms, having densely-growing small leaves when they became adult plants. At the later stages the diseased leaves were blightened. Presence of phytoplasma in plant tissues was confirmed by DAPI-staining fluorescence microscopy and electron microscopy, exhibiting its localization in sieve tubes of stem, petiole, and midrib. This is the first report of potato witches' broom in Korea.

• Journal of Korean Society of Forest Science
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• v.96 no.6
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• pp.737-741
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• 2007

Typical phytoplasma witches' broom symptoms were observed in black locust (Robinia pseudoacacia L.) in Korea. The symptoms of the disease were showing abnormally small leaves, shortened intemodes and proliferation of shoots. The phytoplasmas were detected consistently in all the symptomatic samples by the amplification with phytoplasma universal primer pairs P1/P7 and R16F2n/R2, and the expected size was 1.8 kb and 1.2 kb. However, the phytoplasma DNA was not detected in healthy seedling. Based on sequence analysis of amplified region, this phytoplasma has close homologies with aster yellow, mulberry dwarf, maize bushy stunt, ash witches' broom and sumac witches' broom phytoplasmas, more than 99.2% but showed homologies with black locust witches' broom (GeneBank Accession No. AF 244363), and jujube witches' broom, 88.6% and 87.7%, respectively. This phylogetic analysis indicates that the black locust witches' broom phytoplasma founded in korea should be classified in the Candidatus phytoplasma asteris (16Sr I) group and clearly distinct from the black locust witches' broom group 16Sr III (peach X-disease phytoplasma group).

• The Plant Pathology Journal
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• v.23 no.2
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• pp.106-108
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• 2007

The Symptoms of witches' broom disease caused by phytoplasma including general stunting and yellowing, were observed in leafy lespedeza (Lespedeza cyrtobotrya M.) on Doam-myeon, Pyeongchang-gun, in 2006. Based on the sequence analysis of PCR-amplified 16S ribosomal DNA and 16S-23S spacer region DNA products using universal phytoplasma primers, the phytoplasma associated with leafy lespedeza witches' broom (LLWB) disease was identified as a member of Candidatus Pytoplasma trifolii. It was most closely related to alsike clover proliferation phytoplasma (99.8% similarity, accession no. AY390261), Candidatus Pytoplasma trifolii strain. RFLP patterns generated with AluI, HpaII clearly differentiated LLWB phytoplasma from the referenced phytoplasma strains, water dropwort witches' broom, mulberry dwarf, glehni aster yellow dwarf and jujube witches' broom. This paper is the first report on Candidatus Phytoplasma trifolii in leafy lespedeza identified at a molecular level.

• Korean Journal of Microbiology
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• v.11 no.1
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• pp.19-30
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• 1973

The sweet potatoes infected with witches'-broom disease were collected in the growing fields in Jeon-bug area, Korea. As a possible control plant, Ipomoea batatas L.var. Suwon 147 was selected. The pathogen was identified by various methods ; such as mechanical transmission, antibiotic reactions and electron microscopy. In the results attained the author believed the pathogen of the sweet potato infected with witches' broom to be a mycoplasma-like organism. the results are as follows : 1. Mycoplasma-like bodies were occurred in the phloem region of the sweet potatoes infected with witches'-broom and its particles were sized in the range of about 200-2,500m.mu.. The membrane of the pathogen was observed to be made of an unit. 2. Responsibilities to the antibiotices were sensitive in case of tetracycline and terramycin, and root dipping method showed remarkable than foliage spray. 3. The infection was developed by the grafting transmission but by the insects, Myzus persicae and Cicadella viridis. 4. rosette, witches'-broom, stunt, yellowish, mosaic and necrosis were observed as the symptomps of the disease.

• Plant Disease and Agriculture
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• v.1 no.1
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• pp.30-36
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• 1995

Infection rate of witches'-broom disease (WB) was observed yearly in transplanted jujube seedlings for 7 years. Seedlings of‘Hongan’grafted either on the rootstock from seed (RS) or on the rootstock from rooting (RR) were planted in separate farms. Occurrence of the disease was determined 4 years after transplanting with the witches'-broom symptom. Only 1 seedling of RS was infected with WB, while 56 seedlings of RR showed WB. Yearly infection rates of WB were observed in several varieties of jujube including‘Boeun’,‘Keumsung’,‘Moodeung’,‘Bokjo’,‘Koori’(10 trees for each in Cheongjoo), and‘Hongan’(165 trees in Boeun). In most varieties, WB first appeared in the third year from transplanting, and in the seventh year, more than 80% of the total tree showed WB. The yearly infection rate of newly infected trees was almost. stable during the first years. However, the ratio sharply increased from the sixth year. The accumulated infection rate of WB increased double, year by year from the third to seventh year. Between Cheongjoo and Boeun, no difference in infection rates was found.

• Research in Plant Disease
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• v.17 no.3
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• pp.265-271
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• 2011

Seven phytoplasma diseases have been occurred on floricultural crops in Korea : Ph-ch1 and Ph-ch2 of chrysanthemum, Ph-lily of lily, petunia flat stem-Korean (PFS-K) of petunia, poinsettia branch inducing- Korean (PoiBI-K) of poinsettia, statis witches' broom-Korean (SWB-K) of statis and azalea witches broom (AWB). Classification of the seven phytoplasmal diseases based on 16S ribosomal RNA (rRNA) sequences showed that floricultural crop phytoplasma disease were widespread in order of aster yellow (AY), stolbur and X-disease in Korea. In phenotypic characters, the fasciation was occurred in both monocotyledon plant of lily and dicotyledon plants of petunia and poinsettia. Besides, the fascination was occurred in Ph-lily of stolbur, petunia PFS-K of AY and PoiBI-K of X-disease. This result indicated that phytoplasma classification based on 16S rRNA and symptoms are not consistently related. The comparison of 16S rRNA sequence of the seven floricultural crop phytoplasma with five tree phytoplasmal diseases of jujube witches' broom, paulownia witches' broom, wild jujube witches' broom, mulberry dwarf, golden rain phytoplasma occurred in Korea showed as high as 88.5-99.9% homology. Among them, especially mulberry dwarf showed the highest homology with the seven floricultural crop phytoplasms. Based on this result, floricultural crop phytoplasmas were assumed to be transmitted by insect vectors from tree phytoplasmas in Korea.

• The Microorganisms and Industry
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• v.25 no.2
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• pp.11-18
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• 1999

The sweet potatoes infected with witches'-broom disease were collected in the growing fields in Jeon-bug area, Korea. As a possible control plant, Ipomoea batatas L.var. Suwon 147 was selected. The pathogen was identified by various methods ; such as mechanical transmission, antibiotic reactions and electron microscopy. In the results attained the author believed the pathogen of the sweet potato infected with witches' broom to be a mycoplasma-like organism. the results are as follows : 1. Mycoplasma-like bodies were occurred in the phloem region of the sweet potatoes infected with witches'-broom and its particles were sized in the range of about 200-2,500m.mu.. The membrane of the pathogen was observed to be made of an unit. 2. Responsibilities to the antibiotices were sensitive in case of tetracycline and terramycin, and root dipping method showed remarkable than foliage spray. 3. The infection was developed by the grafting transmission but by the insects, Myzus persicae and Cicadella viridis. 4. rosette, witches'-broom, stunt, yellowish, mosaic and necrosis were observed as the symptomps of the disease.

• Research in Plant Disease
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• v.15 no.1
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• pp.13-16
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• 2009

In April 2008, cherry (Prunus yedoensis Matsumura) in Jeju exhibited severe disease of branches forming numerous twigs. Five isolates from diseased leaves were identified as Taphrina wiesneri on the basis of biological and genetic characteristics. Twenty one commercial fungicides were tested for control of the disease in vitro. Of the 21 fungicides, triazole compounds (difenoconazole, propiconazole and tebuconazole) showed relatively good antimicrobial activities. Results from the planta bioassays indicated that triazole compounds reduced the witches' broom disease showing control value $25.7{\sim}52.8%$ compared with the nontreated controls.

• Journal of Korean Society of Forest Science
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• v.94 no.2 s.159
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• pp.103-107
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• 2005

Typical phytoplasma whiches' broom symptoms were observed in Ash (Fraxinus rhynchophylla Hence) in Korea. The symptoms of the disease were showing abnormally small leaves, shorted internodes and proliferation of shoots. Examination of fluorescent and electron microscopy of leaf midribs revealed numerous phytoplasma bodies localized in the phloem tube cells. The phytoplasmas were detected in all the symptomatic samples by the amplification with phytoplasma specific primer pair P1/P7 consistently, and the expected size was 1.8 kb. However, the phytoplasma DNA was not detected in healthy seedlings. Based on sequence analysis of amplified region, this phytoplasma has close homologies with eqilodium phyllody, mulberry dwarf, and aster yellow phytoplasmas, 99.95%, 99.79% and 99.78%, respectively, This phylogetic analysis indicates that ash witches' broom phytoplasma should be classified in the aster yellow group 16SrVI and clearly distinct from the ash yellow group 16SrVII.