• Mycobiology
• /
• v.30 no.1
• /
• pp.37-40
• /
• 2002

The susceptibility of radiata pine sapwood to fungal attack and the ability of selected fungicides to control colonization of sapstain and mold fungi on green radiata pine sapwood were evaluated. Radiata pine sapwood was highly susceptible to fungal staining, suggesting that prompt application of fungicides after sawing is essential for preventing fungal colonization. The ability of commercial fungicides to prevent fungal discoloration on radiata pine sapwood was assessed using an accelerated 6-week test on small samples in the laboratory, and in field tests using bulk-piled boards exposed outdoors for 6 weeks during summer rainy season. In laboratory tests, Hylite extra provided excellent protection against fungal discoloration even at the lowest concentrations. Hylite clear, Britewood S, and NP-1 Plus provided good short-term protection(2 to 4 weeks), but higher chemical loadings were, required for long-term protection(6 weeks). Woodguard produced little or no protection over the test periods. In field tests, Kathon 893 provided markedly superior protection at the concentration of 0.5 percent or higher. NP-1 Plus provided relatively good protection at all concentrations evaluated. Hylite extra was effective only for short-term protection(2 to 4 weeks) at all concentrations tested, but higher solution strengths were needed for longterm protection.

• Journal of the Korean Wood Science and Technology
• /
• v.51 no.3
• /
• pp.183-196
• /
• 2023

Recently, the morphological and molecular features of five stain fungi infecting rubberwood (Hevea brasiliensis), namely Paecilomyces maximus, Paecilomyces formosus, Penicillium crustosum, Paecilomyces lecythidis and Aspergillus chevalieri, have been studied. Prior to this study, the authors revealed that catechin from gambir (Uncaria gambir) could inhibit the growth of the white-rot fungus Schizophyllum commune, and it was important to determine the bioactivity of the aforementioned agent against A. chevalieri. The efficacy of the biocidal agent was examined using a laboratory wooden block test. Rubberwood blocks, 8 mm in thickness, 20 mm in width, and 30 mm in length, were impregnated with catechin solution at concentrations of 6%, 9%, 12%, and 15% (w/v) using the vacuum-pressure method, and their bioactivity was monitored over three weeks through visual and scanning electron microscope assessment of fungal growth as well as the discoloration intensity of the wood samples. The results showed that catechin treatment increased the resistance of wood samples to A. chevalieri. Overall, the higher the catechin concentration, the lower the fungal growth. The lowest fungal growth was observed in the wood samples treated with 12% and 15% catechin (score of 0), demonstrating no discoloration. In contrast, the fungal growth score of the untreated wood samples reached 4, indicating severe discoloration. Catechins appear to be adequate biofungicides against stain fungi in rubberwood.

• Journal of the Korean Wood Science and Technology
• /
• v.31 no.1
• /
• pp.46-51
• /
• 2003

The feasibility of using bleaching treatments for removing fungal stain was evaluated on heavily stained raiadta pine sapwood. Sodium chlorite and sodium hypochlorite appeared to destain fungal discoloration by providing proper treatment conditions (chemical concentration, treatment temperature, and treatment time), while hydrogen peroxide did not remove fungal stain under the bleaching regimes evaluated. The addition of sodium silicate and sodium hydroxide in the hydrogen peroxide solution as a buffer could remove fungal discoloration completely; however, the color of wood surface turned faint green after bleaching, thereby reducing the lightness of bleached samples. The results suggest that hydrogen peroxide bleaching could be a feasible method for removing fungal discoloration of stained radiata pine sapwood, although further research is needed to solve the problem of color change after bleaching. Also, further tests under field conditions are recommended.

• Journal of the Korean Wood Science and Technology
• /
• v.32 no.2
• /
• pp.82-89
• /
• 2004

Two kinds of chemicals (RNF-3 and RNF-4) with high anti-mold effectiveness against stored fungi causing fungal discoloration was selected from among the six kinds of fluoride-based chemicals in the preceding study. In this study, the anti-mold test using 16 species fungi isolated from the softwood lumbers which were fungal discolored and field test in the sawmill was carried out to prove the feasibility for practical using of selected chemicals.For the isolated fungi, the RNF-3 consist of F and Cu showed high mycelial growth control in the PDA medium and fungicidal effectiveness in the japanese red pine (Pinus densiflora), korean pine (Pinus koraiensis) and radiata pine (Pinus radiata) when the concentration was 2% or more. However the RNF-4 consist of F only was not effective compared with RNF-3 because of mycelial growth in the PDA medium and wood treated with 2% or more chemical solution. The RNF-3 also showed a strong anti-mold effectiveness because there was no fungal discoloration for the radiata pine boards treated by 2% and 10 min. soaking in the field test. These results mean that RNF-3 can be used as domestic anti-stain chemicals for prevention of fungal discoloration of the softwood lumber

• Mycobiology
• /
• v.29 no.4
• /
• pp.205-209
• /
• 2001

The Korean sawmills have recently recognized the importance of prevention of fungal discoloration due to increased losses in revenue. Before establishing integrated control strategies of fungal discoloration, more complete knowledge about causal organisms is needed. As a first step, we initiated a through survey of fungi colonizing commercially important softwood(Pinus dens flora, Pinus koraiensis, and Pinus radiata) logs and lumber in Korea. In this paper we report results obtained from Japanese red pine(Pinus densiflora) log study. In summer 2000, fungi were isolated from Japanese red pine logs in storage, and identified based on their cultural and morphological characteristics. A total of 595 fungi were isolated, representing 21 genera and 30 species. Mold fungi, mostly Trichoderma species, were the most frequently isolating fungi, representing more than half of all isolates. Dematiaceous fungi represented approximately one fifth of the isolates, and Rhinocladiella atorvirens was the most abundant in all samples. Opiostoma species represented 7% of all isolates from cores planted on malt extract agar(MEA) and the incidence of these species doubled with the addition of streptomycin and cycloheximide to MEA. The results indicate that Japanese red pine sapwood is susceptible to colonization by a variety of fungal species. As a result, control strategies that concentrate on one fungus may have limited success because of interference from competing flora.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2013.11a
• /
• pp.170-172
• /
• 2013

To be applied to a humid environment such as bathroom and kitchen, sealant should have good adhesion, tensile strength, etc., it also have the resistance to fungal contamination from the environment. It is important to select right material for sanitary sealing application in order to prevent premature discoloration and fungal activities. Especially for high humidity conditions, it is crucial to have longer mildew and fungal resistance. In this article, we intended to give guide lines for developing right sanitary sealing material and practical test method for evaluating anti-fungal performances reflecting Korean residential life style.

• Research in Plant Disease
• /
• v.19 no.3
• /
• pp.183-187
• /
• 2013

Barley kernel discoloration (KD) leads to substantial loss in value through downgrading and discounting of malting barley. The objective of this research is to investigate fungal distribution and varieties resistance to KD in Korean two-rowed barley. Several fungal organisms including Alternaria spp., Fusarium spp., Aspergillus spp., Epicoccum spp. and Rhizopus spp. were isolated from Korean two-rowed barley representing KD. The symptoms of KD were brown and black discolorations of the lemma and palea. The most frequently detected fungal species was Alternaria spp. which exhibited 69.1% and 72.2% in 2011 and 2012, respectively. Epicoccum spp., Fusarium spp., and Aspergillus spp. were also detected. Fusarium spp., primary pathogen of barley head blight, were rarely occurred in the 2011 and their occurrence increased to 4.7% in 2012. Twenty cultivars of Korean two-rowed barely were evaluated to KD. The average percentage of KD was 8.0-36.0% in 2011 and 5.2-36.6% in 2012. Two cultivars ('Sacheon 6' and 'Dajinbori') showed KD of 6.2% to 8.8% and determined resistant, however 'Samdobori' and 'Daeyeongbori' demonstrating KD of 22.2-36.6% were highly susceptible. 'Jinyangbori', 'Danwonbori', 'Sinhobori' and 'Kwangmaegbori' showing KD of less than 15% were moderately resistant cultivar.

• Journal of the Korean Wood Science and Technology
• /
• v.49 no.6
• /
• pp.591-601
• /
• 2021

Recently it is trend to increase wood use as carbon neutral materials, there is recognized to need necessarily durability improvement of wooden building. It is very rare to report existing on the identification of isolates causing discoloration in domestic weathered wooden building used for long period. The objective of this study was identification of fungi that cause discoloration on the exteriors of weathered domestic wooden buildings in the southern part of South Korea. Our findings can be helpful to establish protection technology for weather deterioration of domestic wooden buildings. Wood chip samples presumed to be contaminated with sapstain fungi were collected from the surface of wooden members used in wooden buildings at Jangheung, Jeollanam-do (two locations, #13 and #14), and Jeju Island (two locations, #31 and #33). The growth of microorganisms was confirmed by performing culture tests for the collected samples, and fungi were isolated, purified, and identified. The results indicated that the fungal strains isolated from wooden buildings #13 and #14 at Jangheung, Jeollanam-do, were 99.83% and 100% homologous to Aureobasidium melanogenum, respectively. For wooden building #31 at Jeju Island (two locations), the fungal strain isolated was 100% homologous to A. melanogenum, which is the same species isolated from the wooden buildings at Jangheung. The fungal strain isolated from wooden building #33 (Jeju Island) had 99.83% homology with A. pullulans, which is commonly found in wood degraded by weather or ultraviolet rays. Our findings can be utilized as a basis for establishing protection technology in domestic wooden buildings.

• Korean journal of applied entomology
• /
• v.25 no.2 s.67
• /
• pp.107-112
• /
• 1986

Species of pathogens and insects associated with grain discoloration in the Philippines were indentified. Leptocorisa oratorios was the most dominant insect species causing discoloration. Pathogenicity tests of fungal organisms isolated from discolored grains showed that Drechslera oryzae, Curvularia lunata, Trichoconiella padwickii, Sarocladium oryzae, Alternaria tenuis, and Fusarium solani were the common pathogens responsible for 'dirty panicle' disease of rice. Discoloration incidence was higher on treatment when both pests were present than when they occurred singly. The discoloration severity was attributed to the pathogens whereas rice bug caused a high decrease in grain weight and unfilled grains. Rice bug feeding on grains enhances the infection caused by the pathogen. Due to this, the quantity and quality of grains produced were affected, resulting in yield reduction.

• Mycobiology
• /
• v.47 no.4
• /
• pp.430-440
• /
• 2019

Fungal contamination of built-in furniture is a frequent problem in Korea when new apartment is built. However, domestic information on the contaminating fungi is very limited. This study was conducted to isolate, identify and characterize the fungi of the problem in one of the apartment houses where the fungi were claimed in the built-in furniture before the house owner moves in. Fungi present in the furniture installed in a main room, dress room, and kitchen side were visually and microscopically confirmed and purely isolated on PDA. The isolated fungi were identified by analyzing the morphological characteristics and nucleotide sequence of the ITS, calmodulin gene, and TEF-1α gene. Aspergillus creber, A. niger, A. pseudoglacus, A. ruber, Cladosporium perangustum and Penicillium commune were identified. Four out of the six fungal species were positive for at least one enzyme in six kinds of extracellular enzyme assays. When these four species (A. creber, A. niger, C. perangustum and P. commune) were inoculated onto four kinds of wood chips of furniture materials, they were able to colonize all of the wood chips. Their settlement was better at 95% humidity condition than at 30% humidity condition. Among the four species, C. perangustum caused the darkest discoloration and secreted the most number of extracellular enzymes. The four species were re-isolated from the colonized wood chips and confirmed as the problematic fungi in the built-in furniture.