• The Korean Journal of Pesticide Science
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• v.19 no.2
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• pp.125-133
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• 2015

Entomopathogenic fungi have been studied to develop for biological control agents as an alternative to chemical control agents in insect pest management. Two Lepidopteran insects, Spodoptera exigua and Plutella xylostella, are serious insect pests infested various crops, but not effectively controlled by commercial chemical pesticides due to its high insecticide resistance. A fungal isolate was isolated from S. exigua larvae collected from green onion field in Andong, Korea. To identify the fungal isolate, 18srRNA sequence for internal transcribed spacer (ITS) and ${\beta}$-tubulin regions were sequenced. The ITS and ${\beta}$-tubulin sequence were highly matched to Beauveria bassiana and morphological characteristics also was fit to known B. bassiana. Finally, isolated fungus has identified as B. bassiana and named B. bassiana ANU1. The result of bioassay, median lethal concentrations were $2.7{\times}10^3$ and $0.9{\times}10^3conidia/ml$ and medial lethal times were 65.6 and 60.8 h to S. exigua and P. xylostella, respectively. B. bassiana ANU1 showed high pathogenicity to two insect pests from $20^{\circ}C$ to $30^{\circ}C$ at 50% relative humidity (RH) and more than 40% RH at $25^{\circ}C$ with $10^7conidia/ml$ of concentration.

• International Journal of Industrial Entomology and Biomaterials
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• v.41 no.2
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• pp.28-35
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• 2020

Entomopathogenic Beauveria bassiana and Metarhizium anisopliae are well-known biological control agents worldwide, and have high potential in industrialization. However, their thermo-susceptibility limits long-term storage under high temperature conditions and insecticidal activity after application in target pests. The virulences of M. anisopliae JEF-003 and JEF-004, and B. bassiana JEF-006 and JEF-007 against bean bug (Riptortus pedestris), and the thermotolerance of conidia produced on three kinds of grains, sorghum, millet and Italian millet as substrates for solid cultures were investigated. Of the three grains, Italian millet was the suitable grains in the production of thermotolerant conidia, and a significant relationship between conidial thermotolerance and the media was demonstrated. This work suggests that biological characteristics of entomopathogenic fungi are altered by culture media, and these results will be a chance to understand the factors in the media which make such changes.

• International Journal of Industrial Entomology and Biomaterials
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• v.17 no.2
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• pp.211-215
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• 2008

To select entomopathogenic fungi controlling aphids effectively, several isolates were screened against second instars of Myzus persicae nymphs in the glasshouse using conidia suspension at $1.0{\times}10^5$ conidia/ml. Among these isolates, SFB-205 conidia showed the highest insecticidal activity about 32.7% efficacy to M. persicae at 4 days after application in the glasshouse. The attachment of SFB-205 conidia on the surface of M. persicae nymphs, and germination and penetration were observed using scanning electron microscopy. SFB-205 was identified as Beauveria bassiana species through the comparison of 5.8 s rRNA genes. There were 24 polymorphisms between SFB-205 and the previously reported isolate, B. bassiana ATCC74040 using six kinds of primer combinations in amplified fragment length polymorphism (AFLP) analysis. The B. bassiana SFB-205 might be used as a practical biological control agent for the green peach aphid, M. persicae in the field.

• International Journal of Industrial Entomology and Biomaterials
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• v.8 no.1
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• pp.77-80
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• 2004

For the development of the alternative control system against the major forest pests, Beauveria spp. F-101, isolated from a dead larva of Thecodiplosis japonensis, was selected because this isolate showed high pathogenicities against T. japonensis and Acantholyda parki. Beauveria spp. F-101 had irregular clustered conidio-phores and conidia borne on a distinctive apical zigzag extension, and it showed typical characteristic of the genus, Beauveria in morphology. For molecular based-identification, the ribosomal ITS region of Beauveria spp. F-101 was amplified with ITS1 and ITS4 primers, and cloned into pGEM- T Easy vector. The amplified PCR product was 569 bp in size and completely sequenced. The similarities of the cloned ITS sequence were 99 ％ and 97％ to those of B. bassiana and B. brongniartii, respectively. In comparison to other species among the genus Beauveria, the ITS region of Beauveria spp. F-101 showed a similarity of 95％ to B. amorpha, 95％ to B. tenella, 89％ to B. vermiconia and 69％ to B. alba, respectively. In addition, in comparison to different genus, it had 95％ similarities to Cordyceps militaris and 91％ to Paecilomyces tenuipes. Accordingly, the current result suggests that Beauveria spp. F-101 was a variant of B. bassiana and it seems to be a new isolate considering sequence variation in ITS region.

• The Korean Journal of Mycology
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• v.28 no.2
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• pp.112-117
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• 2000

A similarity coefficient were analyzed by RFLP of fourteen species of entomopathogenic fungi, isolated from inhabiting pupa and adult insect at forest. Each rDNA ITS I and ITS II with primers of ITS 1 and ITS 4 was amplified by PCR. The amplified products were conserved to 500 bp were not demarcated between genus and species. Four Paeciliomyces tenuipes, two Beauveria bassiana and six Cordyceps militaris were treated by seven restriction enzymes and confirmed in species except JB3 by electrophoresis band. However, the band of C. scarabaeicola showed the identity with B. bassiana. The result of this experiment indicated that the teleomorph of C. scarabaeicola was the same as that of B. bassiana. CfoI and HpaII of seven restricted enzymes were easily discriminating in the genus between Paecilomyees and Cordyceps. Especially, CfoI was more effective to classify the genera of Paecilomyees, Cordyceps and Beauveria than other restriction enzymes. The band patterns of RFLP of P. tenuipes, C. militaris, C. scarabaeicola and B. bassiana were also analyzed by UPGMA program of NTSYS-pc and showed 100% significance. Thus, the similarity coefficient tended to be lower between genera by RFLP analysis, but was higher between species.

• Journal of Microbiology and Biotechnology
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• v.20 no.9
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• pp.1348-1350
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• 2010

Conidia of Beauveria bassiana ARSEF-7060, produced in millet amended with plant oils such as sunflower, corn, or cotton seed oil, were exposed to $45^{\circ}C$ of wet heat for 90 min. Conidia from millet+corn oil medium had the highest thermotolerance [$LT_{50}$ (median survival time): 45.7 min]. The mycotized millet grains were coated with each of the same plant oils as a granular formulation and subjected to $50^{\circ}C$ of dry heat for 8 h. Corn oil coating ($LT_{50}$: 8.68 h) was superior to sunflower and cotton seed oil coatings, suggesting the feasibility of using corn oil to increase conidial thermotolerance.

• Journal of Microbiology and Biotechnology
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• v.20 no.3
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• pp.506-509
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• 2010

The application of Beauveria bassiana SFB-205 supernatant incorporated with polyoxyethylene-(3)-isotridecyl ether (TDE-3) significantly reduced the population of two species of aphids including cotton aphid, Aphis gossypii, and green peach aphid, Myzus persicae, much higher in cotton aphid, compared with supernatant incorporated with Tween 80, which allows the relationship of aphicidal activity with the degradation of aphid cuticles to be determined. Overall, the degradation of the cuticles induced by the supernatant was more remarkable in conjunction with TDE-3 than Tween 80, and this phenomenon was more observable in cotton aphid through SDS-polyacrylamide gel electrophoresis, revealing high correlation with their aphicidal activities.

• Journal of Sericultural and Entomological Science
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• v.42 no.2
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• pp.99-103
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• 2000

This study was carried out to investigate incubating characteristics, LTSEM observation, nature of a disease of infected silkworms(bombyx mori), LD$\_$50/, optimum infective condition for mass production and infection percentage(%) on conservation periods. On the V8 media, the colony was 0.5∼2.0cm/8 days in diameter and white or slighty colored with a white fluffy to powdery appearance. The conidia was subglobos in shape, zig-zag appearance, 1-celled, hyaline and 3.2$\times$2.4 ㎛ in size on the average. The conidiophore was irregular grouped, hyaline, rounded or flask-shaped. The LD$\_$50/ values of the 2nd and 4th silkworms were each other 6.6142(Log) in natural temperature and humidity (25$\^{C}$, 65%). On optimum infective condition for mass production, all of preservation time(hr.) postinoculation in 1.0$\times$10$\^$8/ conidia/㎖ was over 97% and only 20 hr in 1.0$\times$10$\^$7/ condia/㎖ was over 90%.

• Mycobiology
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• v.38 no.2
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• pp.137-143
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• 2010

The production of conidia of entomopathogenic Beauveria bassiana by solid-state fermentation was studied for the development of a biocontrol agent against aphid Myzus persicae. The optimal conditions for conidia production on polished white rice were 40% moisture content, $25^{\circ}C$ culture temperature, 2-day-old seeding culture grown in 3% corn meal, 2% rice bran, 2% corn steep powder medium, initial conidia concentration of $10^7$ conidia/g in the wet rice, 10% inoculum size, and use of a polyethylene bag as a container. The polyethylene bag containing inoculated rice was hand-shaken every 12 hr during fermentation. Using optimal conditions, the maximum conidia production obtained was 4.05 g conidia/100 g dry rice after 14 days of cultivation, a rate 2.83 times higher than conidia yield of pre-optimization.

• International Journal of Industrial Entomology and Biomaterials
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• v.10 no.2
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• pp.131-136
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• 2005

Beauveria bassiana F-101, which has high toxicity toward Acantholyda parki as well as Thecodiplosis japonensis, was an isolate to develop an alternative control system against the major forest pests. Up to now, in B. bassiana, only one pr1 gene has been isolated and characterized. Therefore, we here reported the identification of a pr1-like gene, which would be a factor of toxicity from B. bassiana F-101. The oligonucleotides for the amplification of the pr1-like gene, were chosen based on the conserved regions of the subtilisin family enzymes, pr1 genes of B. bassiana and Metarhizium anisopliae, and proteinase K of Tritirachium album. The cloned PCR fragment had 1111 bp including 52 bp intron. The deduced Pr1-like peptide showed a low identity with Pr1s of entomopathogenic fungi such as B. bassiana Pr1 (BbPr1) and M. anisopliae Pr1 (MaPr1) as well as the proteinase K of T. album (TaPrK). Instead, the deduced peptide had a substantially high amino acid sequence identity $(>65\%)$ with the serine proteases of Magnaporthe grisea (MgSPM1) and Podospora anserina (PaPspA). These results, therefore, appear to suggest that the putative Pr1-like peptide of B. bassiana F-101 belongs to the subtilisin-like serine protease family and may be a novel gene.