• The Korean Journal of Mycology
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• v.46 no.3
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• pp.333-344
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• 2018

Selection of the optimal culture medium and evaluation of the antimicrobial activity against various phytopathogens were performed for four entomopathogenic fungal isolates with excellent insecticidal and antimicrobial activity against the two-spotted spider mite (Tetranychus urticae), green peach aphid (Myzus persicae), and gray mold (Botrytis cinerea). The optimal medium was selected by measuring the amount of blastospore production and the antifungal activity of the culture medium. On the basis of these experiments, GY medium was selected for Beauveria bassiana 2R-3-3-1 and Metarhizium anisopliae 4-2, SD3, and PDB medium for B. bassiana SD15. The antimicrobial activity test against other phytopathogens indicated that all four isolates showed high antifungal activities against Colletotrichum acutatum and Sclerotinia sclerotiorum. However, for Phytophthora capsici and C. fructicola, only M. anisopliae SD3 showed a high antifungal activity against P. capsici, and the other three isolates had little activity. Antibacterial activity against Clavibacter michiganensis subsp. michiganensis was high in two isolates of M. anisopliae but not in two isolates of B. bassiana. Thus, it was confirmed that entomopathogenic fungi effective for pest control could be effectively used as a control agent for various plant diseases.

• Journal of Forest and Environmental Science
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• v.30 no.2
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• pp.243-252
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• 2014

Forest tree species usually takes for long periods to be harvested and cultivated but spearmints are a good model system for woody plant because of reducing and shortening cultivation time. Spearmints are good model plants (Mentha species) for research about terpenoids production and industrial essential oil manufacture. Isopentenyl pyrophosphate isomerase (Iso) and limonene synthase (Limo) are the key enzymes of terpenoid biosynthesis pathway. Transgenic and wild spearmints (Mentha spicata, MS) were cultured in vitro and assessed for the essential oil contents. The content of essential oil of transgenic spearmint also was enhanced slightly depending on the target terpenoid genes. In an attempt to increase productivity of terpenoids further, salt and fungal elicitation strategy was adopted on transgenic Mentha spicata. The salt (800 mM NaCl) as abiotic and two fungi (Botrytis cinerea and Glomerella cingulata) as biotic were used for elicitors. In the absence of salt stress four terpenoids were detected from the spearmint extracts, all of them being monoterpenes. On the other hand, the transgenic (MSIso) extracts contained eleven terpenoids (10 monoterpenes and 1 phenylpropene) while transgenic (MSLimo) extracts contained seven monoterpenes. After 3 days of fungal infection, the resistance indices further increased to 4.38, 3.89 and 2.04 for wild type, MSIso and MSLimo, respectively. The salt and fungal elicitators proved beneficial towards modifying both the terpenoids profile and improvement in the composition of essential oil. These results have important applications for the large-scale production of essential oils and forest biotechnology with respect to spearmint.

• Korean journal of applied entomology
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• v.53 no.2
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• pp.141-147
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• 2014

Pinewood nematode (PWN: Bursaphelenchus xylophilus) is known to kill pine tree species that are indigenous to countries where the pest was inadvertently imported, but some cultures from the extraction of dead pines do not damage trees. Experiments were conducted to examine the effect of pre-inoculation of these low-pathogenic pinewood nematode on resistance of pine trees against the pest species. The pre-inoculated pine saplings showed induced resistance which lasted for a year, and repeated inoculation of these low-pathogenic nematodes enhanced tree resistance. All nematode samples extracted from dying or dead pines that had been killed not more than three months before the extraction were pathogenic, and most of those extracted from pines that had been killed 2-3 years before were low-pathogenic. When inoculated in pine saplings, number of low-pathogenic nematodes settled, as studied two days after inoculation, was not different from that of pathogenic ones. However, as studied after 30 days of inoculation, rate of reproduction in low-pathogenic nematodes was far lower than that of pathogenic nematodes. The rate of reproduction of several nematode isolates growing on fungal mat media of Botrytis cinerea varied, but three of four low-pathogenic isolates showed same level of reproduction rates as pathogenic ones.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.366-371
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• 2010

A study was conducted to examine the effect of precooling (2, 4, or $8^{\circ}C$) and storage (4, 8, or $10^{\circ}C$) temperatures on the storage life of 'Maehyang' and 'Soogyeong' strawberries for export. Fruits at a 70% ripe stage were harvested from a commercial greenhouse in Jinju on March 16, 2010. Fruits were precooled by a forced draft cooling for 3 hours, transported for about 30 minutes to a lab., and then stored. For precooling, small precoolers set in the farm were used. During storage, fruits were examined for their changes in weight, hardness, color (hunter value), soluble solid content, incidence of gray mold (Botrytis cinerea), and marketability at a two days interval from March 16 to March 30. In both cultivars, hardness, sugar content, and hunter value were higher in 'Soogyeong' than 'Maehyang'. The greatest hardness and soluble solid content were obtained after storage at $4^{\circ}C$ in both cultivars. As the ripening stage progressed, hardness and soluble solid content decreased. Also, fresh weight decreased during storage at all temperatures. Gray mold was the greatest at $10^{\circ}C$ storage temperature. The results indicate that effectiveness for keeping the freshness was best achieved by precooling at $2^{\circ}C$ and storage at $4^{\circ}C$ in both cultivars.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.20 no.1
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• pp.17-24
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• 2014

The purpose of this study was to review the brief physiological characteristics and some factors of the quality decay of strawberry harvested in Korea. Strawberries are highly perishable with soft surface. Surface injury and fungus growth are common as a result of handling and distribution. Many growers and distributers are considered to protect the physical impact and inhibit the fungus growth for prolonging the shelf life in the distribution and market channels. Post-harvest treatments of precooling, carbon dioxide, chlorine dioxide, ozone, and ultrasound are practiced on strawberry in order to extend shelf-life and preserve the quality. Modified atmosphere packaging, edible coating, and oxygen absorbent application can be used as supplemental treatments to extend postharvest-life of strawberry. The packaging types for current domestic and export strawberry in Korea were summarized. The findings from this study can be lead to a better understanding of strawberry packaging development associated with the proper handling and distribution of strawberry. This could be useful for the strawberry growers, distributors, and buyers.

• Research in Plant Disease
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• v.12 no.3
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• pp.254-259
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• 2006

Bacillus spp. isolated from mushroom medium wastes were evaluated for their biocontrol potentials on control of Sclerotinia rot of lettuce. The Bacillus isolates were more effectively obtained from waste suspension when directly added into nutrient agar(NA) medium than plating on the agar medium. Totally 42 isolates obtained from the wastes B23 and B42 showed highest antifungal activity against eight fungal pathogens such as Sclerotinia sclerotiorum, Rhizoctonia solani, Pythium ultimum, Phytophthora capsici, Fusarium oxysporum, Colletotrichum gloeosporioides, Cladosporium cucumerinum, and Botrytis cinerea and B23 and B42 were finally selected for further studies. Optimal concentration of the isolates was $10ml(10^7cfu/ml)$ to suppress the Sclerotinia rot of lettuce. Supplements such as starch, glycerol, and egg-yolk successfully maintained the bacterial population for 30 days in vitro and increased bio-control potentials against the disease. The bacterial isolate B23 alone showed 72% control value, furthermore it presented 95% control value when supplemented with 0.2% of starch, glycerol, and egg-yolk. The promising Bacillus isolates B23 and B42 were identified as Brevibacillus brevis and Bacillus stearothermophillus, respectively, based on morphological and physiological characteristics according to API database.

• The Plant Pathology Journal
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• v.33 no.3
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• pp.337-344
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• 2017

To develop a commercial product using the mycoparasitic fungus Simplicillium lamellicola BCP, the scale-up of conidia production from a 5-l jar to a 5,000-l pilot bioreactor, optimization of the freeze-drying of the fermentation broth, and preparation of a wettable powder-type formulation were performed. Then, its disease control efficacy was evaluated against gray mold diseases of tomato and ginseng plants in field conditions. The final conidial yields of S. lamellicola BCP were $3.3{\times}10^9conidia/ml$ for a 5-l jar, $3.5{\times}10^9conidia/ml$ for a 500-l pilot vessel, and $3.1{\times}10^9conidia/ml$ for a 5,000-l pilot bioreactor. The conidial yield in the 5,000-l pilot bioreactor was comparable to that in the 5-l jar and 500-l pilot vessel. On the other hand, the highest conidial viability of 86% was obtained by the freeze-drying method using an additive combination of lactose, trehalose, soybean meal, and glycerin. Using the freeze-dried sample, a wettable powder-type formulation (active ingredient 10%; BCP-WP10) was prepared. A conidial viability of more than 50% was maintained in BCP-WP10 until 22 weeks for storage at $40^{\circ}C$. BCP-WP10 effectively suppressed the development of gray mold disease on tomato with control efficacies of 64.7% and 82.6% at 500- and 250-fold dilutions, respectively. It also reduced the incidence of gray mold on ginseng by 65.6% and 81.3% at 500- and 250-fold dilutions, respectively. The results indicated that the new microbial fungicide BCP-WP10 can be used widely to control gray mold diseases of various crops including tomato and ginseng.

• The Korean Journal of Mycology
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• v.41 no.2
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• pp.118-126
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• 2013

The experiment was carried out to analyze the inhibition effect of plant pathogenic fungi and growth promotion activity induced by the bacterial strains isolated from peatmoss. Among the isolated bacterial strains, B10-2, B10-4, B10-5 and B10-6 which showed more than 30% inhibition rate against Botrytis cinerea and Rhizoctonia solani in vitro, were further analyzed in the greenhouse for the growth promotion activity on lettuce (Lactuca sativa), pak-choi (Brassica compestris L. ssp. chinensis) and Chinese cabbage (Brassica campestris L. ssp. pekinensis). The results showed the treatment of B10-4 on lettuce showed the highest growth promotion activity with the leaf area ($169.17cm^2$), fresh weight (leaf: 40.29 g, root: 8.80 g)and dry weight (leaf: 11.24 g, root: 4.17 g), which was about two folds as compared to control. On pak-choi, the growth promotion rate was the highest with the leaf area of $112.87cm^2$, leaf fresh weight of 60.70 g, root fresh weight of 3.37 g, leaf dry weight of 14.34 g, and root dry weight of 1.90 g. As a result of treatment of B10-13 on chinese cabbage, the growth promotion rate was the highest with the leaf area ($293.56cm^2$), fresh weight (leaf: 113.67 g, root: 2.40 g) and dry weight (leaf: 6.03 g, root: 0.53 g). The production of Indole Acetic Acid (IAA) and Indole-3-Butylic Acid (IBA) were also analyzed in these bacterial isolates. The IAA and IBA analyses were carried out in all bacterial isolates each day within the 5 days of incubation period. The highest production of IAA was observed with $112.57{\mu}g/mg$ protein in B10-4 after 3 days of incubation and IBA production was the highest in B10-2 with $58.71{\mu}g/mg$ protein after 2 days of incubation. Also, phosphate solubilizing activity was expressed significantly in B10-13 in comparison to that of other bacterial isolates. Bacterial identification showed that B10-2 was Bacillaceae bacterium and B10-5 was Bacillus cereus, B10-4 and B10-6 were Bacillus sp. and B-13 was Staphylococcus sp. by ITS sequence.

• Applied Biological Chemistry
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• v.47 no.3
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• pp.321-324
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• 2004

Smoke rods were prepared for 2 insecticides and 5 fungicides using powdered rice chaff as a combustible carrier, and their burning characteristics were investigated. The distribution of active ingredient was investigated after the application of the granular smoke generator containing fenarimol in the connected vinyl plastic house growing cucumber. The protective effects of fungicide smoke generators were evaluated against cucumber gray mold (Botrytis cinerea) and tomato late blight (Phytophthora infestans), and compared with commercial wettable powders. Smoke rods containing powdered rice chaff showed high smoking rates of AI that were higher than commercial smoke pellets. The deposition of fenarimol on the ground of vinyl plastic house was $26.2{\pm}7.7\;ng/cm^2$ when averaged from 9 sites, and application uniformity was found. Also, the protective effects of 5 fungicidal smoke rods against plant diseases were so similar to the commercial wettable powders with no phytotoxicity that smoke rod formulations containing rice chaff as a combustible carrier could be used as an effective formulation for pesticides.

• The Korean Journal of Pesticide Science
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• v.15 no.4
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• pp.495-501
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• 2011

Bacterial strains were isolated from forest soils of Halla mountain, Jeju island in Korea. The soil samples were collected at each altitude of 100m from 1,000 m above sea level. Total 398 strains were isolated and tested for their physiological characteristics of antagonistic and proteolytic activities, and auxin production. Among the isolates, 172 strains were selected as antifungal strains showing antagonistic activity against at least one of 8 plant fungal pathogens (Alternaria alternata, Botrytis cinerea, Collectotrichum acutatum, Fusarium oxysporum, Phytophthora capsici, Pythium ultimum and Sclerotinia sclerotiorum). In addition 203 strains for proteolytic activity and 26 strains for auxin production were characterized for further study. Je28-4 (Rhodococcus sp.) were showed 80% of control value against tomato gray mold in vivo. Thus, it is suggested that soil bacteria isolated from forest soils of Halla mountain can be important sources of bioactive compounds for improving plant growth or promising biocontrol agents.