• KSBB Journal
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• v.14 no.3
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• pp.365-370
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• 1999

To optimize the culture conditions for Beauveria bassiana 726, the effects of culture medium, pH, and temperature on mycelium and spore production were investigated. The optimum temperature and pH for the cultivation of B. bassiana 726 were 28 $^{\circ}C$ and 5.0, respectively. The optimized medium was composed of 1.0~2.0% total sugar from molasses, 0.5% corn steep liquor and 0.05% KH$_2$PO$_4$. In the cultivation of B. bassiana 726 with the optimum medium, the specific growth rate and substrate utilization were well-fitted with the proposed kinetic model in the shake flask and stirred tank reactor. When the fed-batch cultivation using carbon suorce, nitrogen source, and mineral salt as a feeding medium was compared with batch cultivation in stirred tank reactor, mycelium (12.7 g/L) and spore production (5.4$\times$$10^8/mL$) were enhanced up to 110% and 85%, respectively.

• Korean Journal of Organic Agriculture
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• v.31 no.4
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• pp.427-439
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• 2023

The silverleaf whitefly, Bemisia tabaci, is a major pest distributing worldwide damaging over 900 host plant species, and is highly resistant to chemical pesti- cides. Due to the high pesticide resistance of whitefly, there is a need for alternatives to chemical control. Entomopathogenic fungi are candidates for biological pesticide that can overcome the resistance problem of chemical pesticide. Therefore, in this study, we tested pathogenicity of the entomopathogenic fungi to select high insec- ticidal activity against whitefly. As a result, IPBL-C (Cordyceps fumosorosea) and IPBL-F (Metarhizium pinghaense) isolates showed high insecticidal activity against whitefly. Additionally, as a result of culturing the selected isolates on spent coffee grounds medium, the conidia of IPBL-F produced on coffee grounds medium showed five times higher heat stability after heat treatment at 45℃ for one hour than conidia produced on PDA medium.

• The Korean Journal of Mycology
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• v.27 no.1 s.88
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• pp.63-65
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• 1999

Conidiobolus obscurus and C. thromboides (Zygomycetes: Entomophthorales), aphid-attacking fungi, were found on the Dactynotus species (Homoptera: Aphididae) in June 1998 for the first time in Korea. They produce globose primary conidia typical to the genus Conidiobolus but their dimensions are clearly distinguished. Conidiobolus thromboides produces rhizoids and conidiophores with cylindrical constriction at their apices but C. obscurus does not form rhizoids or constricted conidiophores. Resting spores were not found in our specimens of both species, but their vegetative structures observed readily allowed identification.

• Asian Journal of Turfgrass Science
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• v.11 no.3
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• pp.185-191
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• 1997

Biological control of turfgrass insect pest Blitopertha orientalis, forest insect pests, Agelastica coerulea, Meganola melancholia, and Glyphodes perspectalis,vegetable insect pests, Plutella xylostella and Agrotis segetum were conducted with entonopathogenic fungus, Metarhizium anisopliae J-22 isolated from black pine forest soil in Cheju province. Mortality of B. orientalis larvae was 53.3% at the rate of 3.4 $\times$ 1O 7 conidia /ml. A. coerulea and M melancholia larvae showed 100% mortalities at 9.6 $\times$ 106 conidia /ml and 2.7 $\times$ 10 7 conidia /ml as well. However, G. perspectalis larvae were not dead even at 4$\times$ 1O 7 conidia /ml. On the other hand, M anisopliae J-22 was effective against P. xylostella larvae showing 100% mortality at 4 $\times$ 10 7 conidia /ml. KEy words:Entomopathogenic fungi, Biological control, Metarhizium anisopliae, Pathogenicity,Blitopertha orientalis, Agelastica coerulea, Meganola melancholia, Glyphodes perspectalis,Plutella xylostella, Agrotis segetum.

• Korean Journal of Microbiology
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• v.48 no.4
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• pp.284-292
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• 2012

To date, chemical control remains the most common way to reduce beet armyworm (Spodoptera exigua) populations. However, this insect has become more tolerant or resistant to many chemical insecticides and the insect larvae usually hide inside hollow, tube-like leaves of host plant so they were difficult to kill by spraying insecticides. The use of viral and bacterial insecticide to solve these problems has not been successful because of their novel feeding habit. To overcome these problems, in this study, the biological characteristics and virulence of an entomopathogenic fungus isolated from the cadaver of larvae beet armyworm were investigated. Isolated entomopathogenic fungus was identified as Nomeraea rileyi (Farlow) Samson by morphological examinations and genetic identification using sequences of the ITS, ${\beta}$-tubulin gene and EF1-${\alpha}$ regions. This fungus was named as N. rileyi SDSe. Virulence tests against 3rd larvae of beet armyworm were conducted with various conidial suspensions from $1{\times}10^4$ to $10^8$ conidia/ml of N. rileyi SDSe in laboratory conditions. Mortality rate of beet armyworm showed from 20 to 54% and the virulence increased with increasing conidial concentrations. Although N. rileyi SDSe showed low mortality rate against beet armyworm, it is expected that N. rileyi SDSe will be used effectively in the integrated pest management programs against the beet armyworm.

• 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 Life Science
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• v.23 no.8
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• pp.1010-1018
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• 2013

The greenhouse whitefly, Bemisia tabaci, is considered one of the most destructive pests of crops. In this study, we aimed to determine the optimal liquid culture conditions in shake flasks for maximal sporulation of Beauveria bassiana M130 using rice bran. The optimal initial pH for the spore production of B. bassiana using extracted rice bran medium was 5.2 and $28^{\circ}C$. The screening in shake flasks of carbon and nitrogen sources resulted in the identification of an optimal medium based on 0.5% $(NH_4)_2SO_4$, with extracted rice bran 8:1. Using this medium, a production level of $2.15{\times}10^9$ spores per ml was obtained after six days from culture inoculation at $28^{\circ}C$ in a rotary shaking incubator at 130 rpm. In addition, the specific activities of extracellular enzymes of chitinase and protease were $4,296{\mu}mol$ and $375{\mu}mol$, respectively. These results suggest that Beauveria bassiana M130 could be a bio-controller for the greenhouse whitefly.

• The Korean Journal of Mycology
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• v.46 no.4
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• pp.479-490
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• 2018

Red pepper is seriously damaged by thrips (Thrips palmi) and anthracnose caused by Colletotrichum acutatum throughout its development. Because of biotic constraints, producers often depend on chemicals that are expensive and have adverse effects on the environment, operator, and beneficial insects. In addition, resistance is developed because of the repeated use of chemicals. In recent decades, the use of microorganisms in crop protection has become a credible alternative because it is eco-friendly. In this study, we aimed to select isolates with insecticidal and fungicidal activities against the pathogens that cause anthracnose and thrips. We treated T. palmi adults and juveniles with 13 strains of entomopathogenic fungi (isolated from the soil by using the insect-bait method), and 6 strains showed excellent insecticidal activity (70-100%) 5 days after the treatment. The selected isolates were cultured with C. acutatum to screen for the strain with excellent anti-fungal activities, among which an isolate FT333 showed more than 95% control efficacy against C. acutatum in vitro. The isolate was identified as Isaria javanica through its morphological characteristics and phylogenetic analysis of the ITS and ${\beta}-tubulin$ nucleotide sequences. The Isaria javanica FT333 isolate could be used effectively for dual bio-control of thrips and anthracnose during red pepper cultivation.

• Korean journal of applied entomology
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• v.51 no.3
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• pp.245-253
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• 2012

Benzylinedeneacetone (BZA) is a bacterial metabolite which is synthesized by at least two entomopathogenic bacteria, namely Xenorhabdus nematophila and Photorhabdus temperata subsp. temperata. It has been shown to possess inhibitory effects on insect cellular and humoral immune responses as well as antimicrobial activities against various species of bacteria and fungi. However, its relatively high phytotoxicity, and nonsystematic effect have thus far prevented its development into an optimal pesticide. This study screened five different BZA derivatives in order to select an optimal compound, which would have relatively high solubility and low phytotoxicity while retaining sufficient degrees of the immunosuppressive and antimicrobial activities associated with BZA. Hydroxylation of the benzene ring of BZA was found to significantly suppress its immunosuppressive and antimicrobial activities. Transformation of the ketone of BZA by carboxylation also suppressed the inhibitory activities. However, a shortening of the aliphatic chain of BZA into acetate form (4-hydroxyphenylacetic acid: HPA) did not decrease the inhibitory activity. HPA also showed much less phytotoxicity against the hot pepper plant Capsicum annuum, when compared to BZA. This study identified an optimal BZA derivative, which exhibited relatively little phytotoxicity, but retained a high degree of inhibitory activity to suppress insect immune responses and antimicrobial activities against plant pathogens.

• Korean Journal of Agricultural Science
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• v.35 no.2
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• pp.127-136
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• 2008

Beauveria bassiana can be used as a biological insecticide to control a number of pests. It has been known as that B. bassiana TBI-1 have a insecticidal effect on the twospotted spider mite (Teranychus urticae) and the greenhouse whitefly (Trialeurodes vaporariorum) these days. The biological pest control agent, B. bassiana, showed somewhat insecticidal activities against the cotton aphid, Aphis gossypii, too. After treatment with biological insecticide, the mean of increasing rate of aphids was at around recorded at around 0.21 while at around 0.24 in non-treated TBI-1 biological insecticide condition during 1 week. Consequently, it was found that treatment of Beauveria bassiana reduced an increasing rate of aphid population. Also, we could visually observe dead aphids changed as a reddish mold due to this insecticidal fungus. B. bassiana TBI-1 can significantly reduce an increasing rate of aphid population, so effective biological control against the cotton aphid are possible.