• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.134.1-134
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• 2003

Aecial host ranges of four Gymnosporangium species causing cedar-apple rust diseases, G. asiaticum, G. cornutum, 5. japonicum and G. yamadae, were investigated through artificial inoculation. Thirteen species of nine genera among Rosaceous plants, which have been reported as social hosts in Korea, were inoculated with fresh teliospores spores in early days of May of 2000 and of 2001, respectively. In the results, we re-confirmed that there was highly specific relationship between the rust species and aecial hosts and report new aecial hosts of four Gymnosporangium species. Teliospores of G. cornutum collected from Juniperus rigida successively produced spermogonia and aecia only on Sorbus alntifolia, the first report on host alteration of G. cornutum in Korea. Positive responses by teliospores of G. japonicum from J. chinenis of Suwon and from J. chinenis var. horizontalis of Jeju island were obtained only on P. villosa. Crataegus pinnatifida was confirmed as a new aecial host of G. viatium. Until this time, G. ymadae was believed to have Malus as the aecial host. However, teliospores of G. yamadae collected from J. chinensis var. kaizuka successively formed spermogonia and aecia on the leaves of Chaenomeles lagenaria, C. sinensis, Pyrus pyrtifolia var, culta, P. ussuriensis, Malus pumila and M. sileboldii. The date for maturation of spermogonia and aecia, and symptom development varied according to the rust fungi and aecial host plants, respectively.

• The Plant Pathology Journal
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• v.21 no.4
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• pp.310-316
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• 2005

The objectives of this study were to identify the aecial host ranges of four Korean Gymnosporangium species, G. asiaticum, G. cornutum, Gjaponicum and Gyamadae, and to verify the morphological characteristics of telia as diagnostic keys to the species. Thirteen Korean Rosaceous woody species were artificially inoculated with teliospores obtained from Juniperus species. There was high specificity between telial and aecial hosts and the fungal species, providing the first experimental proof on host alternation of these rust fungi in Korea. Telia on the witches' broom and on the small galls were identified as new telial characteristics in G asiaticum and in G. yamadae, respectively. Aecial hosts of G. asiaticum and G. yamadae showed varying responses in their susceptibility and in the days required for formation and duration of spermogonia and aecia after inoculation. Four telial host species in Juniperus were confirmed for the first time in Korea, which include J. chinensis var. kaizuka, J. chinensis var. horizontalis and J. chinensis var. globosa for G. asiaticum; and J. chinensis var. kaizuka for G. yamadae.

• The Plant Pathology Journal
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• v.19 no.6
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• pp.274-279
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• 2003

Two Gymnosporangium species, G. japonicum and G. cornutum, causing cedar-apple rust, were newly identified in Korea, and a new aecial host for each fungus was found by artificial inoculation. Detailed descriptions of the species were made based on macroscopic features (symptoms and signs) and light and scanning electron microscopic observations of spores and peridial cells. G. japonicum from Juniperus chinensis var. horizontalis had Photinia villosa as its new aecial host G. cornutum from J. rigida showed its aecial stage on Sorbus alnifolia.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.133.2-134
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• 2003

Cedar-apple rust fungi had been collected at 36 sites throughout the country from 1984 to 2001 and deposited at the Herbarium of Korea Forest Research Institute (HKFRI). We conducted the morphological examination on the dried specimens by light and scanning electron microscopy and as results six Gymnosporangium species were identified. Three species, G. asiaticum, G. clavaritforme and G. yamadae, were previously described in Korea, while the other three species, G. cornutum, G. globosum, and G. japonicum were new to Korea. Here we present the detailed morphological descriptions, distribution, host ranges and keys to species in both aecial and telial stages of each species. Some morphological characteristics related with telial formation on trees were newly identified; witches brooms for G. asiaticum, small galls for G. yamadae and telial formations on trunk for G. japonicun Geographically G. asiaticum and G. yamadae distributed widely throughout Korea, while the others were collected only at the limited locations. Eight Juniperus species as telial hosts and fifteen Rosaceous plants as aecial hosts were confirmed to be new in Korea.

• The Plant Pathology Journal
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• v.23 no.1
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• pp.7-12
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• 2007

Perilla rust is a damaging disease in perilla cultivation in Korea. Its causal agent was identified as Coleosporium plectranthi based on descriptions of morphological characteristics of spores and spore-producing fruiting structures(in uredinial and telial stages from perilla and in aecial stage from the alternate host pine) collected in 15 locations in Korea during the disease survey from 2004 to 2006. These characteristics were yellow or orange uredinium; globose or ellipsoid urediniospore of $20.8{\mu}m{\times}18{\mu}m$ in size; verruca of $0.3mm{\times}1.2mm$; orange telium; one-celled, oblong ellipsoid teliospore of $63.1{\mu}m{\times}19.7{\mu}m$ with one-layered crusts or four-celled(when mature), internal basidium of $64.2{\mu}m{\times}19.7{\mu}m$; ellipsoid to globoid basidiospore of $20.3{\mu}m{\times}12{\mu}m$; type 2 spermogonium; yellow, broadly ellipsoid peridial cell of $35.6{\mu}m{\times}23.1{\mu}m$; and broadly ellipsoidal or subglobose aeciospore of $25.9{\mu}m{\times}18.8{\mu}m$. Phylogenetic analysis of 28S rDNA sequences revealed the closest relatedness to those of the genus Coleosporium, a monophyletic group distinguished from other rust fungi and divided into two main lineages, one of which was C. plectranthi grouped with high bootstrap value(96%). In pathogenicity test, both aeciospores and urediniospores caused rust development on perilla leaves. This is the first description of C. plectranthi causing perilla rust with the first findings of its telial stage on perilla and the first rust disease on the aecial host in Pinus densiflora. These aspects would provide basic information for the development of control measures of the disease.

• The Plant Pathology Journal
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• v.24 no.1
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• pp.84-86
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• 2008

Field surveys and specimen collections of the rust fungal pathogen Gymnosporangium were carried out for 15 years from 1985 through 1999 in various locations of Korea. Macroscopic and microscopic examinations of morphological characteristics of aecia from the collected specimens revealed that Gymnosporangium globosum is the causal agent of American hawthorn rust disease on Crataegus pinnatifida and C. pinnatifida varmajor. The host plants are new for this rust fungus. G. globosum was found only in Gyeonggi and Chungbuk provinces, indicating that its distribution in Korea is limited. This is a first full description on morphological characters of aecia of G. globosum in Korea.

• Research in Plant Disease
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• v.29 no.3
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• pp.299-303
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• 2023

Rust symptoms on Meliosma myriantha trees have been noticed during disease surveys in Korea since 2010, with a high disease incidence frequently surpassing 90%. The causal fungus of the rust disease was identified as Neophysopella vitis based on the morphological investigation and molecular sequence analysis of the internal transcribed spacer (ITS) and large subunit (LSU) rDNA regions. This is the first report of rust disease caused by N. vitis on M. myriantha in Korea. A pathogenicity assay proved that M. myriantha serves as the aecial host of N. vitis as spermogonia and aeciospores were produced, which can infect the two uredinial hosts, Boston ivy (Parthenocissus tricuspidata) and Virginia creeper (Parthenocissus quinquefolia).

• Research in Plant Disease
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• v.10 no.4
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• pp.279-284
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• 2004

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.

• Journal of Korean Society of Forest Science
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• v.62 no.1
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• pp.76-81
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• 1983

Pedicularis spp. are the alternate hosts of the white pine blister rust fungi in the forests of Korea, and Ribes spp. were found as other alternate hosts by artificial inoculation test. New biotypes (races) with different host selectivity and pathogenicity of the causal fungi were speculated at various places in Korea. The aeciospores of the fungi were collected from two isolated places, Pyeongchang and Namwoen, and artificially inoculated on Pedicularis resupinata and six species of the genus Ribes. Among the tested alternate host species, P. resupinata and R. montigenum were only susceptible to both the Pyeongchang population and the Namwoen population, showing similar pathogencity between the two fungai populations. Three white pine species were planted in fungus-infested stands to study the susceptibility of each tree species. Four years later, 17.7% of Pinus koraiensis and 26.3% of the P. strobus were infected, but P. parviflora was free from attack. From the above results, it was concluded that the white pine blister rust fungus populations in Korea are of the same biotype, with P. koraiensis and P. strobus as aecial hosts, and Pedicularis spp. and Ribes spp. as telial hosts.