• The Korean Journal of Mycology
• /
• v.26 no.4 s.87
• /
• pp.531-537
• /
• 1998

Forest green mold incidence rate, extent of damage according to the inoculation periods, and its cultural characteristics were observed in the automatic cultural system of the winter mushroom, Flammulina velutipes. The incidence rate of the forest green mold was 7.7% in early cultivation stage and slowly increased to 14.9% in harvest stage. When the forest green mold was inoculated at cultural period, the rate was recorded at 100%, but the extent of the damage increased up to 40% (+++). There was also 100% incidence rate at early pinheading time, whereas the yield of mushroom decreased to ++ $(10{\sim}39%)$. The rate of forest green mold was greatly decreased to 34.4% at 10 days after pinheading, and its damage extent was also below 10%. A pathogen to infect the winter mushroom was identified as Trichoderma pseudokoningii. It's optimum temperature for mycelial growth is $25^{\circ}C$, and it grew 2.6 times faster than that of F. velutipes. The mycelial color of T. pseudokoningii was pale yellow or olivaceous in shades on PDA medium. Phialospore was one celled, and ellipsodal or obovoid, smooth walled, and measured $1.3{\sim}3.0{\times}1.0{\sim}2.5\;{\mu}m$. It aggregated in small heads at the tips of the phialides. The phialides were $3.2{\sim}9.2{\times}2.0{\sim}5.5\;{\mu}m$ and were of bowling pin type, solitary and alternate or more irregularly disposed at the conidiophore apex, T. pseudokoningii depressed the F. velutipes growth at the crossing cultivation when they were simultaneously. FV 4-1 (F. velutipes) cultivar was less depressed by T. pseudokoningii, but had a lower cross growth rate than the other four cultivars.

• Journal of Applied Biological Chemistry
• /
• v.60 no.2
• /
• pp.149-153
• /
• 2017

Contamination and growth of Trichoderma, a green mold, on the oak log and wooden chip or sawdust media can severely inhibit the growth of oak mushroom. Chemicals including pesticides and antibiotics are generally not allowed for the control of green mold disease during mushroom cultivation. In this study, bacterial pathogens causing blotch disease on the oyster mushrooms were isolated and their peptide toxins were purified for the control of green mold disease. Strains of Pseudomonas tolaasii secret various peptide toxins, tolaasin and its structural analogues, having antifungal activities. These peptides have shown no effects on the growth of oak mushrooms. When the peptide toxins were applied to the green mold, Trichoderma harzianum H1, they inhibited the growth of green molds. Among the 20 strains of peptide-forming P. tolaasii, strong, moderate, and weak antifungal activities were measured from 8, 5, and 7 strains, respectively. During oak mushroom cultivation, bacterial culture supernatants containing the peptide toxins were sprayed on the aerial mycelia of green molds grown on the surface of sawdust media. The culture supernatants were able to suppress the fungal growth of green molds while no effect was observed on the mushroom growth and production. They changed the color of molds from white aerial mycelium into yellowish dried scab, representing the powerful anti-fungal and sterilization activities of peptide toxins.

• Journal of Applied Biological Chemistry
• /
• v.61 no.1
• /
• pp.69-73
• /
• 2018

Oak mushroom (Lentinus edodes) is cultivated by using oak logs and sawdust medium. Green mold (Trichoderma) infection on these media severely suppresses the growth of oak mushroom. Usages of antibiotics and chemicals are not generally allowed to control of green mold since the mushroom is a fresh food. Tolaasin and its analogues, peptide toxins secreted by Pseudomonas tolaasii, have the antifungal activity and they have been successful to control the green mold disease. When the green mold, Trichoderma harzianum H1, was cultured in the presence of these toxins, the growth of fungus was effectively suppressed. In sawdust media, when the bacterial culture supernatants were sprayed on the aerial hyphae of green molds, the fungal growth was completely suppressed. Particularly, the antifungal activity was greatly increased by the combined culture extracts of P. tolaasii 6264 and HK11 strains. Therefore, these bacterial strains and their peptide toxins were able to suppress the growth of green molds and these can be good candidates to prevent from Trichoderma disease in oak mushroom cultivation.

• Research in Plant Disease
• /
• v.20 no.4
• /
• pp.275-282
• /
• 2014

The occurrence of post-harvest diseases and their pathogens in 'Campbell Early' which is the most produced grape in Korea was investigated. The 'Campbell Early' grapes produced in 3 main grape-producing areas were stored in a cold room ($0-4^{\circ}C$) for 2 weeks then at room temperature for 4 weeks prior to investigation. The major post-harvest diseases occurred were gray mold, blue mold, ripe rot, new decay 1, and new decay 2. Pathogens isolated from the symptoms were identified as Botrytis cinerea for gray mold, Penicillium sclerotiorum for blue mold and Collectrichum acutatum for ripe rot. Pathogens for new decay 1 and new decay 2 were not identified yet. Incidences of new decay 1 and new decay 2 were much higher than the other 3 decays in all grapes produced from 3 areas. Gray mold and blue mold occurred at much lower frequencies than these two decays, and ripe rot occurred least.

• Research in Plant Disease
• /
• v.8 no.4
• /
• pp.220-223
• /
• 2002

In April of 2002, fruit rot infected with blue mold was found at maturing stage of melon (Cucumis melo cv. Gayabaegja) growing under tunnel cultivation in Daesan-myon, Haman-gun, Gyeongnam Province, Korea. Floral parts were infected first and colonized by fungal mycelial mats. From the point of infection, fruits become collapsed and mostly ruptured. The pathogenic fungus from infected fruits was isolated. Colony color of the fungus was white on MEA and CYA agar, Conidia were ellipsoid and 2.6~7.4$\times$2.6~5.8 ${\mu}{\textrm}{m}$ in size. Stipes were 86~320$\times$2.8~4.3 ${\mu}{\textrm}{m}$ in size. Metulae were 12.4~31.6$\times$2.6~4.2 ${\mu}{\textrm}{m}$ in size. Phialides were ampulliform to cylindroid, and 8.2~15.4$\times$3.6~4.6 ${\mu}{\textrm}{m}$ in size. Rate of infected fruits in the field was 4.3%. Based on the cultural and mycological characteristics and pathogenecity test on host plants, the fungus was identified as Penicillium oxalicum, This is the first report on the blue mold of melon (Cucumis melo) caused by P. oxalicum in Korea.

• Research in Plant Disease
• /
• v.12 no.3
• /
• pp.290-293
• /
• 2006

A fruit rot of sweet persimmon(Diospyros kaki cv. 'Fuyu') that infected with blue mold was found during the storage and transport in Jinju Gyeongnam Province, Korea. Fruit surfaces that infected with the fungus were formed water soaked lesion at first then gradually colonized with the fungus and formed mycelial mats. From the point of infection, fruits become sunken and mostly ruptured. The pathogenic fungus was isolated from infected fruits and cultured on potato dextrose agar. The colonies of the pathogenic fungi were white at frist then became greyish green on malt extract agar. Conidia were ellipsoidal and $2.6{\sim}3.8{\times}2.4{\sim}3.8{\mu}m$ in size. Phialides were ampulliform, verticilate of 3-7, $8.0{\sim}9.2{\times}2.0{\sim}3.0{\mu}m$ in size. Metulae were verticils of 2-4, smooth, $9.0{\sim}12.6{\times}3.0{\sim}4.6{\mu}m$ in size. Ramuli were groups 1-3, smooth, $11.0{\sim}17.6{\times}2.3{\sim}3.0{\mu}m$ in size. Rami were groups 1-2, $7.5{\sim}32.6{\times}2.6{\sim}4.2{\mu}m$ in size. Stipes were septate, smooth, thin walled, $56{\sim}302{\times}2.8{\sim}4.0{\mu}m$ in size. Penicilli were mostly quaterverticillate. Based on the cultural and mycological characteristics as well as pathogenicity test on host plants, the fungus was identified as Penicillium expansum. This is the first report on the blue mold of sweet persimmon(Diospyros kaki) caused by P. expansum in Korea.

• Journal of Mushroom
• /
• v.21 no.3
• /
• pp.140-144
• /
• 2023

The objective of this study was to achieve biological control of green mold disease in Pyogo mushrooms using antagonistic microorganisms. Bacillus subtilis BSM320 cells inhibited mycelial growth by 48-60% against three Trichodermaisolates including T. hazianumisolated from the substrates of Lentinula edodes, showing their antifungal activity.The bacteria were cultured to a high density of 4.2 × 10⁹±113.7 cfu/mlin aqueous extract of composted spent mushroom substrates of L. edodes containing 1% glucose and showed a higher growth rate than that observed when using the commercial medium, Luria-Bertani broth. The bacterial culture showed a 75% protective effect without damaging the mushroom fruiting bodies. These results suggest that B. subtilis BSM320culture is suitable for biological control of green mold disease during mushroom cultivation.

• Journal of Mushroom
• /
• v.9 no.3
• /
• pp.110-115
• /
• 2011

Trichoderma disease of oyster mushroom has not been effectively detected in the field for testing its resistance against the disease with its varieties. In this study, we investigated the methods to detect its resistance in the laboratory by using media, which enables us to understand the relevant characteristics (e.g., lysis, toxin enzyme, mycelial growth rate). In coculturing with strains of Trichoderma and oyster mushroom, it is possible to observe the difference in the resistance of oyster mushroom against Trichoderma with the phenomena of barrage reaction, overgrowth and lysis. We also observed the inhibition of mycelial growth of oyster mushroom using the dilution method with 48-well plate, but could not observed the inhibition of mycelial growth using the filter paper method of cultural supernatant. In simultaneously culturing both Trichoderma and oyster mushroom, it was possible to detect the inhibition of the mycelial growth of oyster mushroom, but Trichoderma mycelium did not overgrow against oyster mushroom. We found that the pathogenicity was efficient in using solid medium with the phenomena of overgrowth and lysis by inoculating Trichoderma on top of mycelia of oyster mushroom. In conclusion, the methods (e.g., coculture method, dilution method with 48-well plate, post-inoculation method) are recommended to detect the resistance of oyster mushroom against Trichoderma disease.

• Korean Journal of Organic Agriculture
• /
• v.8 no.3
• /
• pp.121-130
• /
• 2000

In order to screen the antagonistic bacteria which inhibit the growth of the plant pathogen, Penicillum expansum, we isolated an effective bacterial strain and investigated into the antifungal activity of the antagonist and it's identification. The eleven strains of bacteria which strongly inhibited P. expansum were isolated from the nature, and the best antagonistic bacterial strain designated as KB22, was selected. The antagonistic strain KB22 was identified to be the genus Bacillus subtilis based on morphological and biochemical characterization, The KB22 showed 55.9% of antifungal activity against the growth of P. erpansum. By the treatment of the culture broth and the heat treated culture filtrate of it, the B. subtilis KB22 showed 90% and 15% of antifungal activity, respectively.

• The Korean Journal of Mycology
• /
• v.30 no.2
• /
• pp.147-151
• /
• 2002

Trichoderma spp. are the aggressive causal agents for green mold disease on oyster mushroom (Pleurotus spp.) cultivation. Antifungal bacteria (KATB 99121, KATB 99122 and KATB 99123 strains) were isolated from the compost for Pleurotus ostreatus. Among these bacterial strains, KATB 99121 strain showed an excellent inhibitory activity to the pathogens for green molds such as T. harzianum, T. viride and T. hamatum and an animal pathogen, Candida albicans, but did not affect on the culture of Pleurotus ostreatus (2209, Chunchu 2 and Wonhyung strains). KATB 99121 strain secreted amylolytic, proteolytic and cellulolytic exoenzymes. KATB 99122 and KATB 99123 strains excreted amylolytic, proteolytic, cellulolytic, lipolytic exoenzymes and showed ${\beta}$-glucosidase activity. Further studies will be conducted on the development of microbial fungicides using the antagonistic bacteria for the control of green mold disease on Pleurotus spp.