• Korean Journal of Ecology and Environment
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• v.53 no.1
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• pp.73-79
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• 2020

Metarhizium anisopliae is one of the entomopathogenic fungi infecting Protaetia brevitarsis seulensis. Environmental conditions strongly affect the virulence of entomopathogenic fungus. To test the susceptibility of P. brevitarsis seulensis larvae to M. anisopliae, we determined level mortality rates under different rearing conditions: temperatures (20℃, 25℃, 30℃), relative humidities (RH; RH 40%, 50%, 60%, 70%), and water content in sawdust (40%, 50%, 60%). The mortality rate of larvae treated with 5×10⁶ conidia mL^-1 M. anisopliae was not significantly affected by rearing temperature, but was affected by low RH (40%) and low water content in sawdust (40%), both of which resulted in high mortality rates. Mortality rated among M. anisopliae-treated 1^st, 2^nd, and 3^rd instar larvae were highest in 1^st instar larvae.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.445-451
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• 1998

A severe Phytophthora rot of strawberry caused by a species of Phytophthora has been widely occurred at major cultivation areas of Kimhae on August in 1997. Incidence of the disease was obtained in the range of 69.2~83.6% in surveyed 4 fields and showed an average of 75.2%. A species of Phytophthora was mostly isolated from the crown of infected strawberry plants and all the isolates were identified as P. nicotianae var. nicotianae (=P. parasitica). The fungus showed strong pathogenicity on strawberry by inoculation test. As a result of the leaf inoculation using mycelial disks of the fungus, both leaves and petioles were darkly browned, and were finally blighted. As a result of the root inoculation of zoospore suspension, both roots and crowns were rotten with dark brown. Although the fungus produced sporangia either on V-8 juice agar medium or liquid medium, the sporangia observed on the liquid medium appeared to be broadly turbinate and noncaducous. Moreover the fungus cultured on the liquid medium often produced sporangia having two papilla. The number of zoospores in sporangia was found to be ranged from 3 or 4 to as many as 20 or 25. In addition, the released zoospore from the sporangium became the cystospore during the prolonged culture of the fungus. The sporangia were measured as av. 49$\times$35 ${\mu}{\textrm}{m}$ with l/b ratio of 1.43. All isolates from crowns were heterothallic and A1 mating type since oospores were abundantly formed on clarified V-8 juice agar by dual culture with P. capsici A2 mating type. Aplerotic oospores were sized 24-26 ${\mu}{\textrm}{m}$. Antheridia were always amphigynous and recoreded an average of 12$\times$10 ${\mu}{\textrm}{m}$. Hyphal swlling were easily observed, and terminal or intercalary chlamydospores were abundantly formed on V-8 juice agar as well as in C/Z solution and sized av. 28.2 ${\mu}{\textrm}{m}$. This is the first report of Phytophthora rot of strawberry in Korea.

• Research in Plant Disease
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• v.13 no.2
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• pp.119-121
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• 2007

Anthracnose of Salvia plebeia caused by Colletotrichum acutatum was observed in the exhibition field of Hamyang-gun, Gyeongsangnam-do Agricultural Research and Extension Services, in Korea. The disease mainly occurred on the leaves, petioles and stems of whole plant. The typical symptoms were water-soaked lesions on stems and petioles, rotted stems and withering then eventually died. The color of colonies of the pathogenic fungus grown on potato dextrose agar was pinkish gray. Conidia were fusiform in shape and was $8{\sim}17{\times}3{\sim}4\;{\mu}m$ in size. Appressoria were pale to dark brown in color, clavate in shape and the sizes were $8{\sim}11{\times}4{\sim}6\;{\mu}m$. Optimum temperature for mycelial growth was $25^{\circ}C$. On the basis of mycological characteristics and pathogenicity test on host plants, the fungus was identified as Colletotrichum acutatum J. H. Simmonds. This is the first report on the anthracnose of S. plebeia caused by C. acutatum in Korea.

• Research in Plant Disease
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• v.15 no.2
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• pp.127-129
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• 2009

Gray mold caused by Botrytis cinerea occurred on Astragalus sinicus in an experimetal rice field of Gyeongsangnam-do Agricultural Research and Extension Services in Korea from 2008 to 2009. The symptoms appeared on the leaves, petiole and stems of infected plants. and then started with water-soaked, rotted and eventually died blight on plants. The colony were grayish brown and the optimum temperature for sclerotial formation was $20^{\circ}C$ on potato dextrose agar. The conidia were one celled, mostly ellipsoid or ovoid in shape, and were colorless or pale brown in color. The conidia were $7{\sim}16{\times}5{\sim}10{\mu}m$ in size and conidiophores were $14{\sim}28{\mu}m$ in length. On the basis of mycological characteristics and pathogenicity test on host plants, the fungus was identified as Botrytis cinerea Persoon: Fries.

• Korean Journal of Organic Agriculture
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• v.21 no.3
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• pp.373-380
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• 2013

A severe pink mold rot on matured asian pear (Pyrus serotina Rehder) fruit occurred in the organic farmers' orchard in Jinju, Korea in October, 2012. Decay of pear fruit appeared as a softened water-soaked symptom that was easily punctured by pressure. Later pink mycelium appeared on the surface of pear fruit and produced a mass of powdery pink conidia spores. Optimum temperature for mycelial growth of T. roseum was $25^{\circ}C$. Conidia showed hyaline, smooth, 2-celled, thick-walled with truncate bases, ellipsoidal to pyriform, and characteristically held together zig-zag chains and $10{\sim}22(34){\times}6{\sim}10(12){\mu}m$ in size. Conidiophore was erect, colorless, unbranched type, and 4-5 ${\mu}m$ width. On the basis of mycological characteristics, pathogenicity test, and molecular identification with the ITS region, the causal fungus was identified as Trichothecium roseum (Pers.) Link ex Gray.

• Journal of Korean Society of Forest Science
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• v.79 no.3
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• pp.322-329
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• 1990

A group of Pinus densiflora trees attacked by Rhizina root rot were observed at Kangnung. Diseased roots are characterized by rot patches, radial rot traces or formation of adhesive soil masses. The damage has proceeded about 6m per annum, and the pathogen in the infected soil was detected by trap logs. Ascospores of Rhizina undulata was germinated by heat shock at $37^{\circ}C$ for 24 hours or at $40^{\circ}C$ for 17 hours. The mycerial growth was optimum on PDA medium at $25-30^{\circ}C$and pH 5.6-6.3. Coniferous trees were more susceptible than non-coniferous trees in inoculation test in vitro.

• The Korean Journal of Mycology
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• v.34 no.2
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• pp.122-124
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• 2006

In March of 2005, gray mold disease caused by Botrytis cinereu on Stachys sieboldii Miq. was occurred in the mud cellar storage of Gyeongsangnam-do Agricultural Research and Extension Services, Korea. The symptoms started with water-soaked and rotten in the tubers. The conidia were one celled and mostly ellipsoid or ovoid in shape and light gray in color. The conidia were $5{\sim}16{\times}4{\sim}12{\mu}m$ in size and the conidiophores were $14{\sim}30{\mu}m$ in length. The pathogen formed conidia and sclerotia abundantly on PDA. The optimal temperature for mycelial growth and sclelotia formation was $20^{\circ}C$. On the basis of symptom, mycological characteristics and pathogenicity test on host plants, the fungus was identified as Botrytis cinerea Persoon: Fries. This is the first report on gray mold of S. sieboldii caused by B. cinerea in Korea.

• The Korean Journal of Mycology
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• v.33 no.1
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• pp.35-37
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• 2005

Anthracnose symptoms on Spiraea prunifolia were observed around the residential area of Dongbumyon, Geoje City, Gyeongnam Province, Korea in 2002 and 2003. Typical symptoms of the disease were dark red spot on the leaves and black spot on the stem. The pathogen formed gray to dark gray colony on potato dextrose agar. Conidia were single celled, color, ovoid or oblong in shape and $6{\sim}12\;{\times}\;3{\sim}5\;{\mu}m$ in size. Seta were dark brown in color, cone-shaped in shape and $23{\sim}42\;{\times}\;2{\sim}4\;{\mu}m$ in size. The optimum temperature for growth of the isolate was about $25{\sim}30^{\circ}C$. On the basis of mycological characteristics and pathogenicity test on host plants, the fungus was identified as Colletotrichum gloeosporioides. This is the first report on the anthracnose of S. prunifolia caused by C. gloeosporioides in Korea.

• Research in Plant Disease
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• v.11 no.1
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• pp.85-87
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• 2005

In July 2003, a destructive stem rot occurred sporadically in an exhibition farm on Aster glehni of Hamyanggun, Gyeongsangnam-do Agricultural Research and Extension Services, Korea. The typical symptoms of the disease were water-soaking, stem rot, wilt or blight. The infected plants were mostly died. White mycelial mats were spread over lesions and sclerotia were formed on stems and near soil line. The sclerotia were globoid or irregular in shape, 1~3 mm in size, and white to brown in color. The optimum temperature for fungal growth was about 30oC. Clamp connections were observed in the hyphae of the fungus grown on potato dextrose agar, and hyphal diameter was 3~8 ${\mu}m$. On the basis of mycological characteristics and test of pathogenicity to host plants, the fungus was identified as Sclerotium rolfsii. This is the first report on the stem rot of Aster glehni caused by S. rolfsii 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.