• The Plant Pathology Journal
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• v.15 no.6
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• pp.330-334
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• 1999

Applying the method of quantitative analysis of pycnidiospore from the detached warts produced by the infection of Botryosphaeria dothidea on apple stems, repeated productivity of spores within the detached warts, variations in the amount of spores within the detached warts, variations in the amount of spores by the length of induction time for sporulation, and the effects of temperature and moisture on the sporulation were investigated. In addition to these experiment, the changes in the state of spores within the pycnidia contained in the warts accompanied by the induction of sporulation and dispersal of spores were also investigated. When detached warts were kept in moist conditions, the sporulation and discharge of spores were also investigated. When detached warts were kept in moist conditions, the sporulation and discharge of spores could be repeated several times, and the amount of spores were almost constant after each repeat of sporulation induction and dispersal of spores in a given period. The fact that the pycnidia filled with spores were observed at considerable rates within the warts which were subjected to the shaking in the water to release spores indicated that the spores might never be released until the pycnidia were fully matured. From the high rate of empty pycnidia even in the warts which were kept in moist conditions for induction of sporulation, the pycnidiospores might be produced through the development of new pycnidia. A considerable amount of pycnidiospores were produced at $5^{\circ}$, and the sporulation was accelerated with the rise of temperature until $35^{\circ}$. When the warts were supplied with sufficient moisture, sporulation was further accelerated. The results obtained in these experiment will be applied in developing the method for assessing the inhibitory efficacies of fungicides on the sporulation of this fungus, with which a new control measure would be developed.

• Korean journal of applied entomology
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• v.18 no.4 s.41
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• pp.183-188
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• 1979

The study has been carried to describe a new disease of strawberry in Korea, which was found in 1977 at Kimhae. Symptom of the disease occurred mainly on leaves as showing large annular brown spots or 'V' shaped brown lesions. Many of dark pycnidia were observed from the both side of old lesions. The pathogen was identified as Dendrophoma obscurans (Ell. & Ev) Anderson which has not been described in Korea as a pathogen of strawberry disease. The common name of the disease was given, temporaly, as Annular leaf blight of strawberry. In the laboratory study, light was necessary for the production of pycnidia and potato dextrose agar was the best media for tile pycnidia formation. There were some difference on resistance to the disease among 48 tested strawberry varieties though none of them shelved highly resistant reaction, and the older leaves showed more susceptible reaction than younger ones.

• Journal of Korean Society of Forest Science
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• v.96 no.5
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• pp.515-519
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• 2007

An imperfect fungus Fusiococcum species was isolated from Quercus dentata. A naturally infected Daimyo oak tree was collected and showed elongate wounds on the stem. The fungal cultures were initially white and cottony, and later turned dark gray. Numerous solitary pycnidia were developed on the medium surface, and typically spherical. Yellowish conidial masses were exuded from pycnidia on the culture plates. Conidial masses were swollen and measured as approximately 100 to $300{\mu}m$ in length. It appeared that conidia were usually held together in globose to oval drops. Conidia were hyaline, single-celled (nonseptate), ellipsoid to fusoid, and measured as approximately $8.0{\times}2.7{\mu}m$. Based on these cultural and morphological characteristics, the fungal isolate was identified as a species of Fusicoccum Corda. To preserve and examine fungal spores exuded from pycnidia on the medium surface, a vapor fixation procedure for scanning electron microscopy was employed in this study. The specimens were exposed to the vapor of 2% (v/v) glutaraldehyde and 2% (w/v) osmium tetroxide each for 2 h. With the vapor fixation we obtained excellent retention of conidial masses in this study. The simple and versatile procedure for demonstrating fungal spores and their exudation from fruiting bodies would facilitate characterization of diverse pathological and environmental isolates as they are in native environments.

• The Plant Pathology Journal
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• v.17 no.6
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• pp.347-349
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• 2001

Black blights attacked the blossom and flower buds of wild chrysanthemum (Chrysanthemum boreale) in the experimental field in Hamyang in 1998. The infection rate of the disease on the plant ranged from 4.0 to 91.8%. The pathogen isolated from the infected flower buds produced numerous conidia in pycnidia. The pycnidia, which were immersed into the petals, emerged through the epidermis by short ostiolate neck. Conidia had 0-3 septate (mostly uniseptate) and were 10-27.5 $\times$5-7.5 ㎛ in size. The fungus produced pseudothecia on potato dextrose agar (PDA), and uniseptate ascospores produced in asci were 10$\times$2.7 ㎛ in size. The pathogen also produced pycnidia and pycnidiospores on PDA after 4 weeks in the dark condition. The conidia produced on PDA were smaller than those from infected plants. Based on the examined mycological characteristics, the fungus was identified as Didymella chrsanthemi.

• Korean Journal Plant Pathology
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• v.14 no.1
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• pp.46-51
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• 1998

A method for inoculum production of Botryosphaerisa dothidea was developed using cucumber disks and cereal media. Disks of cucumber fruits, and cereal media of barley, wheat, and rice seeds were inoculated with mycelial plugs of B. dothidea and incubated at 27$^{\circ}C$. Pycnidia were produced on the surface of cucumber disks and seeds after 5 days of inoculation. When the inoculated barley seeds were immersed in sterilized distilled water for 5 minutes, abundant conidia of B. dothidea were exuded from mature pycnidia. Conidia were held together by mucilage as they were released from an ostiole. Compared with the conventional method for inoculum preparation using agar media, such as potato-dextrose agar and oatmeal agar, this method could minimize the tedious work required for inoculum preparation within a shorter period of time.

• Korean journal of applied entomology
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• v.16 no.4 s.33
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• pp.211-215
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• 1977

The Sporulation of Didymella bryomiae were observed under diurnal cycles of light/darkness of near ultraviolet light (NUV) and artificial daylight (ADL) and continous darkness in eight isolates growing on PDA and V-8 juice agar. Light stimulated pycindial and perithecial formation of this fungus on potato dextrose agar and V-8 juice agar. Sprulation was poor in darkness, but some isolates were able to produce pycnidia and perithecia in the absence of light. Perithecial formation was much better under artificial daylight (ADL) on V-8 juice agar than those grown under near ultraviolet light (NUV). In general, cultures grown on V-8 juice agar sporulated better than cultures grown on PDA under three setsof light condition. Most of the pycnidiospores obtained from each isolates of this fungus grown on PDA were non-septate and microtype, but macrotype of non-septate and uniseptate pycnidiospores were produced on V-8 juice agar. Pycnidiospore produced on V-8 juice agar were similar to those produced on the radicle of naturally infected seeds. The appearance of perithecia were quite distinctive from pycnidia. The mature perithecia were darker than pycnidia and whitish spore masses formed on the ostiole of perithecia.

• The Korean Journal of Mycology
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• v.22 no.3
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• pp.260-265
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• 1994

Since around 1980 apple rot caused by Botryosphaeria dothidea has become prevalent throughout the growing areas in Korea, during which period chemical controls have been executed with no notable improvement. Results of investigations on resistance of the causal fungus to its control chemical are as followings; The susceptible fungal isolates showed no mycelial growth at $150\;{\mu}g/ml$ of benomyl whereas the resistant isolates showed 7-13 mm growth at $300\;{\mu}g/ml$ and 6-8 mm at $2,400\;{\mu}g/ml$ of this fungicide. At the latter high concentration, spore germination of the resistant isolates was 5-9% while that of the susceptible isolates was 0%. Within the range of $20-2,400\;{\mu}g/ml$ tested, the susceptible isolates were unable to form pycnidia, but the resistant isolates formed abundant pycnidia at the lower concentration with decreasing pycnidia along with the higher concentration.

• Research in Plant Disease
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• v.11 no.1
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• pp.16-20
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• 2005

Several time-course experiments were carried out to understand seasonal development of melanose on yuzu trees at koehung area, Jeonnam province, during May to October. The occurrence of dead twigs, known as a source of infection, was much more in older trees, and from June to August, mostly in July. In the experiment of pycnidia development on dead twigs seasonally collected, the number of developed pycnidia was highest on July-collected dead twigs especially with the diameter of 1.1~1.5 cm. In the collection survey of disseminated pycnidiospores, although the collected number of pycnidiospores was affected with amount of precipitation, the number of observed pycnidiospores in rainwater was relatively high from June to August, with highest in early August in 1997 and late July in 1998. In the inoculation tests on 3-year-old trees and fruits in natural condition, disease occurrences were mostly affected on twigs by inocula treatment in June, and on fruits by inocula treatment in July, respectively.

• The Korean Journal of Mycology
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• v.29 no.2
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• pp.116-122
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• 2001

An isolate of the prospective hyperparasite, Ampelomyces quisqualis 94013 (AQ94013) was selected for the use of biological control of cucumber powdery mildew caused by Sphaerotheca fuliginea. Examination for the parasitism processes by scanning electron microscopy and light microscopy showed that conidia of AQ49013 germinated on conidia, conidiophores and hyphae of Sphaerotheca fuliginea four hours after inoculation. Appressorium-like structures were developed and attached to the hyphae of S. fuliginea seventeen hours after inoculation. Hyphae of AQ94013 penetrated into hyphae of S. fuliginea twenty-four hours after inoculation. Pycnidia of AQ94013 were produced in the hyphae and the basal part of conidiophores of S. fuliginea fourty four hours after inoculation. The pycnidia of AQ94013 matured foully eight hours after inoculation, and the conidia were discharged from the ostioles of the pycnidia fifty two hours after the inoculation. At the same time, hyphae and conidiophores of S. fuliginea were distorted and died. Also, concentrated culture filtrate and culture filtrate of AQ94013 had not suppressed the cucumber powdery mildew fungus as water treatment. Therefore, mode of action of AQ94013 was assumed to be parasitism on powdery mildew fungi.

• Mycobiology
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• v.51 no.3
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• pp.115-121
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• 2023

The fungal strain KNUF-22-18B, belonging to Cucurbitariaceae, was discovered from a stink bug (Hygia lativentris) during the investigation of insect microbiota in Chungnam Province, South Korea. The colonies of the strain KNUF-22-18B were wooly floccose, white to brown in the center on oatmeal agar (OA), and the colonies were buff, margin even, and colorless, reverse white to yellowish toward the center on malt extract agar (MEA). The strain KNUF-22-18B produced pycnidia after 60 days of culturing on potato dextrose agar, but pycnidia were not observed on OA. On the contrary, N. keratinophila CBS 121759^T abundantly formed superficial pycnidia on OA and MEA after a few days. The strain KNUF-22-18B produced chlamydospores subglobose to globose, mainly in the chain, with a small diameter of 4.4-8.8 ㎛. At the same time, N. keratinophila CBS 121759^T displayed a globose terminal with a diameter of 8-10 ㎛. A multilocus phylogeny using the internal transcribed spacer regions, 28S rDNA large subunit, b-tubulin, and RNA polymerase II large subunit genes further validated the uniqueness of the strain. The detailed description and illustration of the proposed species as Neocucurbitaria chlamydospora sp. nov. from Korea was strongly supported by molecular phylogeny.