• The Korean Journal of Pesticide Science
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• v.21 no.1
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• pp.90-96
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• 2017

Gray mold disease, cause by Botrytis cinerea, occurs severe damage on varieties of fruit and vegetable production, and have no a critical control method. In case of chemicals control, it is a trigger emergence of drug resistance strains due to using them continuously. In addition, the pathogen is difficult to control naturally because it is possible to survive regardless of host status. In this study, microorganisms were isolated from tomato flower and hive samples and in order to select suitable microbial control agents for tomato gray mold disease. During six-months study, we isolated 1,004 isolates from flower and 925 isolates from pollinator hive samples. Among them, 6 strains were selected based on result of antifungal activity test. The selected strains showed not only strong antifungal activity against gray mold pathogen, but also cellulase and protease enzyme activities. The selected strains were identified as Paenibacillus polymyxa. In plant assay, P. polymyxa prevented the gray mold disease occurrence near 75%.

• Journal of Life Science
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• v.25 no.8
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• pp.910-916
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• 2015

Scientists have recently shown an interest in the characteristics of Bacillus mojavensis strains because of their increasing use in plants as a defense against diseases and mycotoxins. We have shown here that B. mojavensis KJS-3 possesses the typical characteristics of B. mojavensis strains including a strong resistance to high temperatures (≤50℃), tolerance to high salt concentrations (7% NaCl), ethanol tolerance (40% ethanol), and pH range for growth (pH 5-9). B. mojavensis KJS-3 has been used for the production of cyclic lipopeptides including important antifungal substances such as surfactin, iturin, and fengycin. Polymerase chain reaction analysis in this study showed that B. mojavensis KJS-3 can be used for the production of fengycin and the findings of LC-MS/MS analyses suggest that B. mojavensis KJS-3 can be used to produce iturin and surfactin. Antifungal activity analys is confirmed that B. mojavensis KJS-3 has antifungal effects on Botrytis cinerea, Rhizoctonia solani AG-4, Sclerotinia sclerotiorum, and Colletotricum goeosporioides. A microscopy assessment of the roots of wild ginseng plants planted together with B. mojavensis KJS-3 revealed that the roots contained B. mojavensis KJS-3, confirming the bacteria to be a plant growth promoting endophyte (PGPE) which acts against plant diseases and mycotoxins. Our findings lead us to conclude that B. mojavensis KJS-3 can be produced at an industrial level as a microbial pesticide or microbial fertilizer.

• Microbiology and Biotechnology Letters
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• v.26 no.4
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• pp.369-372
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• 1998

Microbial insecticide formulations were prepared by liquid and semi-solid fermentations using Bacillus thuringiensis subsp. kurstaki, HL-106 (BTK-HL106), B. thuringiensis subsp. israelensis HL-63 (BTI-HL63) and B. sphaericus 1593 (BS-1593) strains. The liquid fermentation medium contained molasses 2%, dextrose 1.5%, peptone 2%, D-xylose 0.025%, CaCl$_2$ 0.1%, K$_2$HPO$_4$ 0.1%, KH$_2$PO$_4$ 0.1%, MgSO$_4$$.$7H$_2$O 0.03%, FeSO$_4$$.$7H$_2$O 0.002%, ZnSO$_4$$.$7H$_2$O 0.02%. The composition of the semi-solid fermentation medium was rice bran 45.2%, zeolite 31%, yeast powder 0.02%, corn powder 5%, dextrose 3%, lime 0.3%, NaCl 0.06%, CaCl$_2$ 0.02%, and H$_2$O 15.42%. Insecticide formulations produced in the liquid fermentation named BTK-HL106, BTI-HL63 and BS-1593 pesticides and those in the semi-solid fermentation were designated as BTK-HL106-1, BTI-HL63-1 and BS-1593-1 pesticides, respectively. The number of spore (endotoxin crystals) was 2.65${\times}$10$\^$9/ spores per $m\ell$ in the BTK-HL106 and 3.5${\times}$10$\^$10/ in the BTK-HL106-1 3.8${\times}$10$\^$9/ spores in the BTI-HL63 and 7.0${\times}$10$\^$10/ in the BTI-HL63-1, and 7.5${\times}$10$\^$9/ in the BS-1593 and 1.4${\times}$10$\^$10/ in the BS-1593-1. The spores in the BS-1593 formulation was produced two times more than the other formulations. The spores in the BTI-HL63-1 were contained twice than those in the BTK-HL106-1, and five times than those in the BS-1593-1. The results indicated that spore (endotoxin crystals) productions in the semi-solid fermentation increased about ten times than those in the liquid fermentations. $LC_{50}$s of the BTI-HL63 and BS-1593 were 4.5 $\mu\textrm{g}$, and those of the BTI-HL63-1 and BS-1593-1 were 1.5 $\mu\textrm{g}$. $LC_{50}$ of the BTK-HL106 was 1.5 mg and that of the BTK-HL106-1 was 0.9 mg. The $LC_{50}$s of the formulations in the semi-solid fermentations showed about two to three times higher than those in the liquid fermentations.

• Journal of Microbiology and Biotechnology
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• v.17 no.10
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• pp.1700-1703
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• 2007

Microorganisms capable of degrading crude oil were isolated and grown in soybean oil as a sole carbon source. The microbial cultures were used to control green peach aphids in vitro. Approximately 60% mortality of aphids was observed when the cultures were applied alone onto aphids. To examine the cultures as a pesticide formulation mixture, the cultures were combined with a low dose of the insecticide imidacloprid (one-fourth dose of recommended field-application rate) and applied onto aphids. The cultures enhanced significantly the insecticidal effectiveness of imidacloprid, which was higher than imidacloprid alone applied at the low dose. The isolated microorganisms exhibited high emulsifying index values and decreased surface tension values after being grown in soybean oil media. GC/MS analyses showed that microorganisms degraded soybean oil to fatty acids. The cultures were suggested to play the roles of wetting, spreading, and sticking agents to improve the effectiveness of imidacloprid. This is the first report on the control of aphids by using oil-degrading microbial cultures.

• Korean journal of applied entomology
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• v.49 no.4
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• pp.409-416
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• 2010

An entomopathogenic bacterium, Photorhabdus temperata ssp. temperata (Ptt), suppresses insect immune responses and facilitates its symbiotic nematode development in target insects. The immunosuppressive activity of Ptt enhances pathogenicity of various microbial pesticides including Bacillus thuringiensis (Bt). This study was performed to select a cheap and efficient bacterial culture medium for large scale culturing of the bacteria. Relatively cheap industrial bacterial culture media (MY and M2) were compared to two research media, Luria-Bertani (LB) and tryptic soy broth (TSB). In all tested media, a constant initial population of Ptt multiplied and reached a stationary phase at 48 h. However, more bacterial colony densities were detected in LB and TSB at the stationary phase compared to two industrial media. All bacterial culture broth gave significant synergism to Bt pathogenicity against third instars of the diamondback moth, Plutella xylostella. Production of bacterial metabolites extracted by either hexane or ethyl acetate did not show any significant difference in total mass among four culture media. Reverse phase HPLC separated the four bacterial metabolites, which were not much different in quantities among four bacterial culture broths. This study suggests that two industrial bacterial culture media can be used to economically culture Ptt in a large scale.

• Journal of Life Science
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• v.12 no.3
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• pp.369-373
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• 2002

The waste-water from the industry for production of a soybean curd (the soybean curd waste-water) was investigated to use for the substrate to produce the endotoxin of Bacillus thuringiensis subsp. kurstaki HD-1 used as one of well known microbial pesticides. The pH of the soybean curd waste-water was 9.8 and its chemical oxygen demand (COD), total nitrogen (TN) and phosphate (TP) were 276.0, 71.1 and 5.5mg/$\ell$, respectively. The higher was the concentration of the soybean curd waste-water in the medium, the more endotoxin was produced. Maximal sporulation occurred at which concentration of $K_2$HPO$_4$in the medium supplied with the soybean curd waste-water was 1% (w/v). Production of the endotoxin with the optimized medium supplied with the soybean curd waste-water was 1.5 times higher than that without the soybean curd waste-water. The soybean curd waste-water was found to be suitable substrate for production of the endotoxin of Bacillus thuringiensis subsp. kurstaki HD-1.

• Korean journal of applied entomology
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• v.62 no.4
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• pp.277-285
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• 2023

The onion moth, Acrolepiopsis sapporensis, was monitored in the farms cultivating the welsh onion, Allium fistulosum, using sex pheromone from transplantation to harvest. Two occurrence peaks were observed at early June and late July after the overwintering population. However, the population sizes were varied among different years and the cultivating environments. To effectively control A. sapporensis with microbial pesticides, different Bacillus thuringiensis strains were screened to select B. thuringiensis kurstaki (BtK). To enhance the insecticidal virulence of BtK, the culture broth of Photorhabdus temperata temperata (Ptt) was added to the BtK. This mixture of two entomopathogenic bacteria was called 'BtPlus', which was superior to BtK alone in the insecticidal virulence. The enhanced virulence was explained by the immunosuppressive activity of the secondary metabolites contained in the Ptt extract. The metabolites inhibited both cellular and humoral immune responses of A. sapporensis, resulting in the enhanced virulence of BtK. These results suggest that A. sapporensis occurs in the welsh onion fields and the resulting economic damage would be effectively prevented by BtPlus application.

• Journal of the East Asian Society of Dietary Life
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• v.7 no.4
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• pp.502-511
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• 1997

This study was to Investigate the consumer's understanding and purchasing foods, which were produced by organic agricultured method. The results of this study were as follows: 1. When shopping foods, the items which were deeply considered were taste of family and food safety. 2 Contaminants which were considered to be dangerous were, in decreasing order, agricultural chemical residue, food additives, environmental contaminant, and microbial hazard. Consumer's perception to agricultural chemical residue In foods was 'be much serious' and over 4.0 by Likert 5 scale. 3. Among of characteristics which was associated with organic farmming foods, taste and nutrition were considered the least important characteristic, whereas safety and good health were considered the most important characteristic. 4. The foods which were thought to be polluted by agricultural chemical residue were, in decreasing order fruit, vegetable, cereal, egg, meat, milk, and fish & shellfish. 5. The respondants' purchasing degree for organic farmming foods was 'often purchase' and 3.44 by Likert 5 scale. These result showed significant difference for age(p＜0.05), for education level (p＜0.05), for income(p＜0.05) and for food expenditure(p＜0.05), respectively 6. The type of organic farmming food which frequently purchased were, in decreasing order, vegetable. fruit, egg, cereal, milk, and meat. The reasons why consumer purchased organic farmming food were, in decreasing order, no pesticide/therbicides, no artifical fertilizer, no growth regulators, residue free, and good quality. 7. 78% of respondants Indicated that they bought organic farmming food in this year increasely or same as last year and 91.9% of respondants Indicated that they plan to buy organic farmming foods in next year.

• Korean Journal of Medicinal Crop Science
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• v.22 no.4
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• pp.270-275
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• 2014

This study was conducted to select and develop effect of eco-friendly organic materials for the eco-friendly prevention of Anthracnose occurred in the ginseng. Anthracnose on ginseng is occurred by Colletotrichum gloeosporioides and the crop damage is severe especially from July to August after rainy season. The test results showed that control effect by test products materials on the three years ginseng and four years ginseng field was lower in eco-friendly organic materials than that of chemical pesticide. However, the control effect of bordeaux mixture was higher with 71.3% and 73.8% levels than those of mineral matter, microbial agent, and developed plants extract mixtures (Eugenol, Curcumin, Wood vinegar, etc). On the other hand, three types of developed plants extract mixtures (3 types) showed control effect in a range of from 58.1% to 63.6% against Anthracnose which was higher as compared with plant extract alone and sodium silicate regardless of ages of ginseng. The results of this study would attribute in verifying the control effect of eco-friendly materials against Anthracnose for ginseng through investigating antimicrobial compounds contained in the plants body. Also, it would be used as control method against Anthracnose occurred in ginseng by judging the right control time through monitoring occurrence of disease.

• Journal of Microbiology and Biotechnology
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• v.8 no.6
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• pp.685-691
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• 1998

Baculovirus Hyphantrin. cunea nuclear polyhedrosis virus (HcNPV) insecticide containing the insecticidal protein (ICP) gene from Bacillus thuringiensis subsp. kurstaki HD1 was constructed using a lacZ-HcNPV system. The ICP ($\delta$-endotoxin) gene was placed under the control of the polyhedrin gene promoter of the HcNPV. A polyhedrin-negative virus was derived and named ICP-HcNPV insecticide. Then, the insertion of the ICP gene in the ICP-HcNPV genome was confirmed by Southern hybridization analysis. Polyacrylamide gel electrophoresis (PAGE) analysis of the Spodoptera frugiperda cell extracts infected with the ICP-HcNPV showed that the ICP was expressed in the insect cells as 130 kDa at 5 days post-infection. The ICP produced in the cells was present in aggregates. When extracts from the cells infected with the ICP-HcNPV were fed to 20 Bombyx mori larvae, the following mortality rate was seen; 8 larvae at 1 h, 10 larvae at 3 h, and 20 larvae at 12 h. These data indicate that the B. thuringiensis ICP gene was expressed by the baculovirus insecticide in insect cells and there was a high insecticidal activity. The biological activities of the recombinant virus ICP-HcNPV were assessed in conventional bioassay tests by feeding virus particles and ICP to the insect larvae. The initial baculovirus insecticide ICP-HcNPV was developed in our laboratory and the significance of the genetically engineered virus insecticides is discussed.