• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.422-428
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• 2014

Endophytic bacterial strains from root tissue of strawberry were screened for their efficacy in growth improvement and control of Phytophthora blight disease of chili pepper plant under greenhouse condition. Plants treated with the strain EP103, identified as Pseudomonas fluorescens, showed growth improvement in terms of fresh weight and root length compared to the untreated control and other endophytic strains. When challenged with Phytophthora capsici, there was significant reduction of disease in EP103 treated plants with an efficacy of 78.7%. There was no direct inhibition of the target pathogen by EP103 when tested under in vitro antibiosis assay. Analysis of differential expression of selected marker genes for induced systemic resistance (ISR) in plants treated with EP103 and challenged with P. capsici showed up-regulation of PR1 and PR10 pathogenesis-related (PR) proteins. PCR analysis showed that EP103 produced secondary metabolites such as pyoluteorin, pyrrolnitrin, hydrogen cyanide and orfamide A. This study indicated the potential of endophytic P. fluorescens strain EP103 as an efficient biocontrol agent against P. capsici in chili pepper plant.

• Korean Journal of Food Science and Technology
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• v.30 no.5
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• pp.1140-1145
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• 1998

Low density polyethylene (LDPE) films incorporated with 1% antimicrobial agents of Rheum palmatum extract, Coptis chinensis extract, and Ag-substituted inorganic zirconium matrix, were applied to modified atmosphere packaging of 200 g fresh strawberries. Plain LDPE film package, PVC wrap and perforative pinhole package of the film impregnated with 1% Rheum palmatum extract were also constructed for comparative purpose. All the packages were stored for 13 days at $5^{\circ}C$ and measured in package atmosphere, microbial count and quality attributes of the strawberry fruits. The antimicrobial LDPE films retarded the growth in total aerobic bacteria, lactic acid bacteria and yeast on the fruits, and resulted in significantly lower decay. The degrees of reduced microbial growth and fruit decay in the antimicrobial film packages were more pronounced, when applied by hermetical sealing to produce the modified atmospheres of low $O_2$ (<4.0%) and $CO_2$ concentrations with $6.3{\sim}9.0%$. The hermetically sealed packages of antimicrobial LDPE films also showed better retention of fruit firmness and did not give any negative effect on the physical and chemical qualities of strawberries.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.355-360
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• 2013

Diesel-burning air heater (air heater) and infrared heating lamp (infrared heater) were installed as auxiliary heaters in two single water-curtained plastic greenhouses with a set night temperature of $6^{\circ}C$ for cultivation of strawberry 'Seolhyang'. The average night air temperature was $6.6^{\circ}C$ in the infrared heater treatment and $7.1^{\circ}C$ in the air heater treatment. However, when the minimum outside temperature fell below $-10^{\circ}C$, the air heater had less internal temperature fluctuations. In contrast, the infrared heater had some cases of falling below the set temperature. The relative humidity was higher than 98% by the side-effect of water-curtain system regardless of the heating system. There was about $5^{\circ}C$ difference in leaf temperature between the turned-on and -off state of the infrared heater, and the efficacy of the infrared heater on leaf temperature was only limited to about 4 meters from the system. Peduncle length and plant height in the infrared heater tended to be greater than those in the air heater. There was, however, no statistically difference in leaf size and numbers of leaves, flowers on first cluster and branches. There was no difference in soluble solids content, fruit firmness, average fruit weight of the harvested fruits, and the yield. Comparing the heating costs, the air heater system took 622,662 won based on 543 L tax-free diesel, while the infrared heater system took 235,284 won by consuming 5,685 kWh of electricity, and 62.2% heating costs saving was achieved.

• Journal of the Korean Society of International Agriculture
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• v.30 no.4
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• pp.300-304
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• 2018

'Bokha' is a new strawberry (Fragaria x ananassa Duch.) cultivar, which was released by the Highland Agriculture Research Institute in 2016. The 'Bokha' cultivar originated from a cross between 'Goha' and 'Saebong No. 3' that showed excellent ever-bearing characteristics, including continuous flowering habit and high soluble-solids contents under long-day and high temperature conditions in 2011. This cultivar was initially named 'Saebong No. 8' after examining its characteristics and productivity in summer culture from 2013 to 2015. After regional adaptability tests in 2016, 'Bokha' was selected from Saebong No. 8 as an elite cultivar. The general characteristics of 'Bokha' include semispreading type, elliptical leaves, and moderately vigorous growth. The fruits are conical in shape, and red in color. 'Bokha' plants have 32.7 leaves, 9.9 more than 'Goha' plants. The soluble-solids content of 'Bokha' was 9.2%, which was 0.2% higher than that of 'Goha'. The average fruit weight of 'Bokha' was about 9.5g and the marketable yield was $27,701kg{\cdot}ha^{-1}$, 72% higher than 'Goha'. 'Bokha' is suitable for tropical and subtropical zone cultivation as a high soluble solids contents cultivar, because it shows continuous flowering habit under long-day and high temperature conditions.

• Food Science and Preservation
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• v.17 no.2
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• pp.196-201
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• 2010

Gelatin films containing grapefruit seed extract (GSE) were prepared by incorporating different amounts (0, 0.6, and 1.0%, w/v) of GSE into film-forming solutions. Film elongation was improved by the addition of GSE, but film tensile strength decreased to 31.96 MPa for film containing 1.0% GSE, compared with 46.39 MPa for the control. Incorporation of 1.0% GSE inhibited the growth of pathogenic bacteria such as Escherichia coli O157:H7 and Listeria monocytogenes. Packaging of strawberries with a gelatin film containing 1.0% GSE decreased the levels of total aerobic bacteria and yeast/molds after 12 days of storage by 1.60 and 1.43 log CFU/g, respectively, compared with control values. Sensory evaluation results indicated that packaging of strawberries with GSE-gelatin film resulted in better sensory scores than those of the control. These results indicate that strawberries can be packaged using gelatin film containing GSE, to extend shelf-life.

• Korean Journal of Food Science and Technology
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• v.45 no.2
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• pp.191-198
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• 2013

The storage quality of fresh Sulhyang strawberries packaged under modified atmospheres was investigated to examine the effect of high $O_2$ on the fruit. Fresh strawberries were packed into PP trays and top-sealed with PET/PP film. Initial gas compositions inside the packages were varied with air, 40% $O_2$/60% $N_2$, 60% $O_2$/40% $N_2$, and 80% $O_2$/20% $N_2$. Sealed packages in PE film bags with air and perforated PP trays were also used as another treatment and control, respectively. Quality attributes and viable cell counts of pathogenic bacteria were assessed during storage at $5^{\circ}C$ for 12 days. High $O_2$ concentration showed no significant effects on the physicochemical and microbial qualities of strawberries. Fruit packaged in PE film bags with 6-15% $O_2$ and 7-9% $CO_2$ during storage had the lowest viable cell counts of inherent microorganisms among the treatment samples. Growth of pathogenic bacteria was suppressed in perforated packages where molds occurred frequently. In an overall sensory aspect, the PE film packages exhibited higher scores than the others at the end of storage period. The experimental results suggested that gas-permeable film packaging with an appropriate combination of $O_2$ and $CO_2$ rather than gas-barrier tray packaging with an initially high $O_2$ concentration would be suitable for improving the storability of strawberries.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.6
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• pp.901-908
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• 2014

Blueberries and strawberries are highly perishable and easily contaminated with microorganisms. To maintain the quality of these commodities during refrigerated storage, the effects of two packaging materials as well as passive modified atmosphere packaging on the quality of blueberries and strawberries were investigated. The harvested blueberries and strawberries were first treated with combined non-thermal treatment of aqueous chlorine dioxide and fumaric acid, followed by packaging with polyolefin film (6,000 mL $O_2/m^2{\cdot}24hr{\cdot}atm$ at $24^{\circ}C$) and polyamide/polyamide/polyethylene film (PA/PA/PE, 60 mL $O_2/m^2{\cdot}24hr{\cdot}atm$ at $24^{\circ}C$), respectively. After combined sanitizer treatment, the populations of total aerobic bacteria in blueberries and strawberries were reduced by 2.50 and 1.97 log CFU/g while those of yeast and molds were reduced by 1.95 and 2.18 log CFU/g, respectively, compared with the control. In particular, microbial growth in these samples packed with PA/PA/PE film was reduced during refrigerated storage. In addition, the blueberries and strawberries packed with PA/PA/PE film underwent lower weight loss than those packed with polyolefin film during storage. These results suggest that appropriate packaging with proper gas permeability is necessary to maintain the quality of blueberries and strawberries during refrigerated storage.

• Research in Plant Disease
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• v.8 no.1
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• pp.1-10
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• 2002

Climate in the year of 2001 could be summarized as severe drought from March to May, unusually high temperature in whole plant growth periods and clear weather condition especially in harvesting time of September and October without any typoons. In rice, major diseases such as leaf and panicle blast, bacterial blight, sheath blight and bacterial grain rot developed little due to unfavorable weather conditions, however, brown spot occurred severely due partly to the reduced use of N-fertilizer, Rice stripe virus infection was unusually high mainly in the west coast areas with four times more diseaseD area campared to the previous year, In pepper phytophthora blight was extremely severe in Cheonnam and Cheonbuk provinces, where had frequent rainfalls during growing period. Incidence of major diseases of tomato and cucumber in 2001 was relatively mild. In watermelon, penicillium fruit rot, one of the peculiar disease, spread over major production areas, whereas CGMMV, usually severe in every years was much reduced. Watermelon plants growing in open-fields were more severely diseased than those in plastic houses. Major diseases of chinese melon and strawberry occurred slightly and in particular, sudden wilt syndrome of chinese melon which was severe in 2000 showed mild infections in 2001. Incidence of white rot of garlic and onion was much lower unlike other years due mainly to spring drought and high temperature in the growing period. Infected area of potato bacterial wilt tended to increase in 2001 while fusarium wilt of sweetpotato was decreased. Apple diseases were generally mild, but powdery mildew of pear increased sharply. Barley scab was not severe as seen in other years.

• Korean Journal of Agricultural Science
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• v.19 no.2
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• pp.170-178
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• 1992

Isolates of Botrytis cinerea resistant to dicarboximide fungicides were collected from strawberry fields in greenhouses in spring and early summer of 1990. Five out of 9 isolates of B. cinera were resistant, which showed mycerial growth on PDA containing dicarboximide fungicides(procymidone and vinclozolin) with concentrations of 100, 400 and $1,600{\mu}g/ml$. The minimal inhibitory concentration(MIC) values of the dicaboximide-resistant isolates was more than $6,400{\mu}g/ml$, while that of the sensitive isolates was less than $6.25{\mu}g/ml$. The germination ratio of conidia of the resistant isolates on PDA containing procymidone and vincolozolin was more than 95%, while that of the sensitive was less than 15%. The procymidone-resistant isolates were also resistant to vinclozolin, showing cross-resistant between the fungicides, but cross-resistant was not observed between the dicarboximides and dichlofluanid. Resistance to benomyl was also found in all the dicarboximide resistant isolates. Occurrence frequency of dicarboximide-resistant isolates out of 223 isolates was about 40%. The resistant isolates were widely distributed throughout Korea.

• Korean Journal of Microbiology
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• v.52 no.2
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• pp.212-219
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• 2016

Forty-nine pigments were extracted from the collections of 106 pigment producing bacteria from the plant rhizosphere soil. Antibacterial activity test was performed in the subjects of the extracted pigments with plant pathogenic bacteria including Xanthomonas axonopodis and Xanthomonas campestris, and with plant pathogenic fungi including Botrytis cinerea, Colletotrichum acutatum, and Fusarium oxysporum. The yellow pigment by Chryseobacterium sp. RBR9 and the red pigment by of Methylobacterium sp. RI13 showed the antibacterial activities against Xanthomonas axonopodis and Xanthomonas campestris. The violet pigment by Collimonas sp. DEC-B5 showed the antibacterial activity as well as the antifungal activities against Botrytis cinerea and Fusarium oxysporum. Especially, the violet pigment inhibited the growth of Botrytis cinerea more than 65% at MIC $20{\mu}M$. Upon the HPLC analysis result for the isolation of pigment with antifungal activity, violacein (91.6%) and deoxyviolacein (8.4%) were isolated for the pigment by Collimonas sp. DEC-B5. The production amount of the pigment was increased more than 10 times higher when D-mannitol 1.5% and yeast extract 0.2% were added as the nitrogen source to SCB medium. This study suggests that produced violacein by Collimonas sp. DEC-B5 will be effective to control strawberry gray-mold rot fungi by its preventive activity.