• Research in Plant Disease
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• v.24 no.4
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• pp.353-358
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• 2018

An effective bioformulation of mixtures of chitin-degrading bacteria has been used successfully to control plant diseases and nematodes. In this study, the bioformulation approach was assessed to control damping-off disease of ginseng. In pot experiments with soils infested with dapming-off pathogens of ginseng, root-drenchings of Chrobacterium sp. C-61, Lysobacterium enzymogenes C-3, and mixture of two bacterial strains grown in chitin minimal medium were signficantly increased emergence of seeds and reduced damping-off disease incidence of seedlings. Efficacy of the bioformulated product depended on the dose and timing of application. In two-year-old ginseng field, the high control efficacies were achieved by soil drenching of two times with an undiluted product or three times with a 10-fold diluted product. In a To-jik nursery (self soil nursery), biocontrol efficacy of the undiluted product against damping-off disease were similar to that of a seed dressing with fungicide, Tolclofos-methyl WP. These results suggest that the bioformulated product containing Chromobacterium sp. C-61 and L. enzymogenes C-3 could be an effective approach to control of ginseng damping-off disease.

• Research in Plant Disease
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• v.13 no.1
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• pp.40-44
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• 2007

Powdery mildew of pepper is one of the most devastating diseases which is occurring all the year under greenhouse condition. In this study, control efficacy against powdery mildew was evaluated by mixed culture solutions of two chitinolytic bacteria, Lysobacter enzymogenenes strain C-3 and Chrornobacterium sp. strain C-61, cultivated in the chitin-supplemented medium. In all experiments, white powder on the reverse side of pepper leaves perfectly disappeared 3 days after application of mixed culture solutions. However, periods required for formation of new white powder on the same sites after application (control-lasting period) were largely differed according to environmental conditions. In particular, the control-lasting period was much longer when sprayed on 6 PM than 9 AM and especially, on rainy days than sunny days. This indicates that control efficacy of culture solution may be largely affected by environmental conditions after application. The undiluted culture solution resulted in a perfect control with control value more than 95% by application of 5-day-intervals under severely diseased field and 7-day-intervals under disease-started field. A ten-fold diluted product also showed control value more than 81% by application of the same method. These results suggest that this culture solution can be practically used to control powdery mildew disease in pepper plants.

• Journal of Microbiology and Biotechnology
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• v.18 no.8
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• pp.1408-1415
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• 2008

To produce polyhydroxyalkanoate (PHA) from inexpensive substrates by bacteria, vegetable-oil-degrading bacteria were isolated from a rice field using enrichment cultivation. The isolated Pseudomonas sp. strain DR2 showed clear orange or red spots of accumulated PHA granules when grown on phosphate and nitrogen limited medium containing vegetable oil as the sole carbon source and stained with Nile blue A. Up to 37.34% (w/w) of intracellular PHA was produced from corn oil, which consisted of three major 3-hydroxyalkanoates; octanoic (C8:0, 37.75% of the total 3-hydroxyalkanoate content of PHA), decanoic (C10:0, 36.74%), and dodecanoic (C12:0, 11.36%). Pseudomonas sp. strain DR2 accumulated up to 23.52% (w/w) of $PHA_{MCL}$ from waste vegetable oil. The proportion of 3-hydroxyalkanoate of the waste vegetable-oil-derived PHA [hexanoic (5.86%), octanoic (45.67%), decanoic (34.88%), tetradecanoic (8.35%), and hexadecanoic (5.24%)] showed a composition ratio different from that of the corn-oil-derived PHA. Strain DR2 used three major fatty acids in the same ratio, and linoleic acid was the major source of PHA production. Interestingly, the production of PHA in Pseudomonas sp. strain DR2 could not occur in either acetate- or butyrate-amended media. Pseudomonas sp. strain DR2 accumulated a greater amount of PHA than other well-studied strains (Chromobacterium violaceum and Ralstonia eutropha H16) when grown on vegetable oil. The data showed that Pseudomonas sp. strain DR2 was capable of producing PHA from waste vegetable oil.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.110.3-111
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• 2003

The effect of biological control on the severity of hot pepper wilt disease was evaluated in the vinyl house with plants cultivated in the nursery soil containing chitin and chitinolytic microorganisms. The chitinolytic microorganisms, Trichoderma harzianum and Chromobacterium sp. strain C-61, were well survived in the nursery soil containing chitin. The hot pepper damping-off was markedly suppressed in the nursery soil containing chitin and chitinolytic microorganisms. The survival of chitinolytic microorganisms and suppression of damping-off were superior as the amounts of chitin added to the nursery soil increased, but growth of hot pepper was inhibited in the 10％ (w/w) chitin treatment. When the plants cultivated in the nursery soil containing 1％ chitin and chitinolytic microorganisms were transplanted in the vinyl house, the vegetative growth increased and the wilt disease was reduced as comparison with those of control.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.110.2-110
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• 2003

The effect of biological control on the severity of hot pepper wilt disease was evaluated in the vinyl house with plants cultivated in the nursery soil containing chitin and chitinolytic microorganisms. The chitinolytic microorganisms, Trichoderma harzianum and Chromobacterium sp. strain C-61, were well survived in the nursery soil containing chitin. The hot pepper damping-off was markedly suppressed in the nursery soil containing chitin and chitinolytic microorganisms. The survival of chitinolytic microorganisms and suppression of damping-off were superior as the amounts of chitin added to the nursery soil increased, but growth of hot pepper was inhibited in the 10％ (w/w) chitin treatment. When the plants cultivated in the nursery soil containing 1％ chitin and chitinolytic microorganisms were transplanted in the vinyl house, the vegetative growth increased and the wilt disease was reduced as comparison with those of control.

• Research in Plant Disease
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• v.20 no.2
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• pp.112-118
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• 2014

A liquid bio-formulation containing chitinolytic bacteria, chitin and their products was assessed for its potential biological control against root-knot nematodes on cucumber. The bio-formulation was prepared by cultures of three chitinolytic bacteria, Chromobacterium sp. strain C-61, Lysobacter engymogenes and Serratia plymuthica in minimal medium supplemented with chitin. Under pot conditions, the bio-formulation showed better growth of cucumber plants, and less root galls and population density of Meloidogyne spp. than control media without the bio-formulation. In a greenhouse, 75-fold diluted bio-formulations were treated instead of water around cucumber plants through hoses for drip irrigation six times at 5-day intervals from the transplanting date. After 30 and 60 days, the treatment provided about 7% and 10% enhancement in the plant height and about 78% and 69% reduction in population density of Meloidogyne spp. in the rhizosphere, respectively. In addition, the experiments showed that the control effects occurred only in the soils contacted with the bio-formulation. Undiluted bio-formulations were drenched three times at 10-day intervals around cucumber plants severely infested with Meloidogyne spp. The treatment showed about 37% plant enhancement without dead plants compared with 37% death in the untreated control, and about 82% nematode reduction. These results suggest that the bio-formulation can be practically used to control the root-knot nematode on cucumber.