• Mycobiology
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• 제46권4호
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• pp.440-447
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• 2018

Dual biocontrol of both insects and plant pathogens has been reported for certain fungal entomopathogens, including Beauveria bassiana and Lecanicillum spp. In this study, we demonstrate, for the first time, the dual biocontrol potential of two fungal isolates identified by morphological and phylogenetic analyses as Isaria javanica. Both these isolates caused mortality in the greater wax moth, and hence can be considered entomopathogens. Spores of the isolates were also pathogenic to nymphs of the green peach aphid (Myzus persicae), with an $LC_{50}$ value of $10^7spores/mL$ 4 days after inoculation and an $LT_{50}$ of 4.2 days with a dose of $10^8spores/mL$. In vitro antifungal assays also demonstrated a strong inhibitory effect on the growth of two fungi that are pathogenic to peppers, Colletotrichum gloeosporioides and Phytophthora capsici. These results indicate that I. javanica isolates could be used as novel biocontrol agents for the simultaneous control of aphids and fungal diseases, such as anthracnose and Phytophthora blight, in an integrated pest management framework for red pepper.

• Journal of Microbiology and Biotechnology
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• 제18권12호
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• pp.1915-1918
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• 2008

An entomopathogenic fungus was isolated from an infected aphid. The isolate conformed most closely to Lecanicillium attenuatum CBS 402.78 (AJ292434) based on the internal transcribed spacer (ITS) region of its 18S rDNA, and thus was designated L. attenuatum CNU-23. Laboratory and field evaluations of CNU-23 blastospores were carried out for the control of green peach aphids. The laboratory evaluations of CNU-23 revealed an aphid mortality of about 80% with an estimated $LT_{50}$ of 3.72 days after the application of CNU-23 at $1{\times}10^6$ blastospores/ml. Meanwhile, the field evaluations of CNU-23 performed on greenhouse pepper plants during the rainy season showed an aphid mortality ranging from 72% to 97%. Significant sporulation was observed in the aphids treated with CNU-23. Therefore, the results suggest that L. attenuatum CNU-23 can be used as a biocontrol agent for green peach aphids on greenhouse pepper plants.

• Journal of Microbiology and Biotechnology
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• 제23권2호
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• pp.167-176
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• 2013

A novel bioactive molecule produced by Bacillus thuringiensis subsp. kurstaki Bn1 (Bt-Bn1), isolated from a common pest of hazelnut, Balaninus nucum L. (Coleoptera: Curculionidae), was determined, purified, and characterized in this study. The Bt-Bn1 strain was investigated for antibacterial activity with an agar spot assay and well diffusion assay against B. cereus, B. weinhenstephenensis, L. monocytogenes, P. savastanoi, P. syringae, P. lemoignei, and many other B. thuringiensis strains. The production of bioactive molecule was determined at the early logarithmic phase in the growth cycle of strain Bt-Bn1 and its production continued until the beginning of the stationary phase. The mode of action of this molecule displayed bacteriocidal or bacteriolytic effect depending on the concentration. The bioactive molecule was purified 78-fold from the bacteria supernatant with ammonium sulfate precipitation, dialysis, ultrafiltration, gel filtration chromatography, and HPLC, respectively. The molecular mass of this molecule was estimated via SDS-PAGE and confirmed by the ESI-TOFMS as 3,139 Da. The bioactive molecule was also determined to be a heat-stable, pH-stable (range 6-8), and proteinase K sensitive antibacterial peptide, similar to bacteriocins. Based on all characteristics determined in this study, the purified bacteriocin was named as thuricin Bn1 because of the similarities to the previously identified thuricin-like bacteriocin produced by the various B. thuringiensis strains. Plasmid elution studies showed that gene responsible for the production of thuricin Bn1 is located on the chromosome of Bt-Bn1. Therefore, it is a novel bacteriocin and the first recorded one produced by an insect originated bacterium. It has potential usage for the control of many different pathogenic and spoilage bacteria in the food industry, agriculture, and various other areas.

• International Journal of Industrial Entomology and Biomaterials
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• 제47권1호
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• pp.1-11
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• 2023

The Indian golden muga silkworm, Antheraea assamensis Helfer is an economically important wild silkworm endemic to Northeastern part of India. In recent years, climate change has posed a threat to muga silk production due to the requirement that larvae be reared outdoors. Since the muga silkworm larvae are exposed to the vagaries of nature, the changing climate has increased the incidence of microbial diseases in the rearing fields. Accurate diagnosis of the disease causing pathogens and its associated epidemiology are prerequisites to manage the diseases in the rearing field. Although conventional microbial culturing methods are widely used to identify pathogenic bacteria, they would not provide meaningful information on a wide variety of silkworm pathogens. The information on use of molecular diagnostic tools in detection of microbial pathogens of wild silk moths is very limited. A wide range of molecular and immunodiagnostic techniques including denaturing gradient gel electrophoresis (DGGE), random amplified polymorphism (RAPD), 16S rRNA/ITSA gene sequencing, multiplex polymerase chain reaction (M-PCR), fluorescence in situ hybridization (FISH), immunofluorescence, and repetitive-element PCR (Rep-PCR), have been used for detecting and characterizing the pathogens of insects with economic significance. Nevertheless, the application of these molecular tools for detecting and typing entomopathogens in surveillance studies of muga silkworm rearing is very limited. Here, we discuss the possible application of these molecular techniques, their advantages and major limitations. These methods show promise in better management of diseases in muga ecosystem.

• 한국토양동물학회지
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• 제9권1_2호
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• pp.1-5
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• 2004

2002년에서 2004년까지 3월에서 11월 사이에 무궁화를 가해하는 해충과 천적에 관해 조사한 결과 해충은 5목 9과 12종, 비곤충류 2목과 2과 2종이 조사되었다. 목별로는 매미목(Homoptera) 5종과, 나비목(Lepidoptera) 3종, 딱정벌레목(Coleoptera) 2종, 메뚜기목(Orthoptera) 1종, 노린재목(Hemiptera) 1종, 응애목(Acarina) 1종, 병안목(Stylommato-phora) 1종이 조사되었다. 무궁화 해충 중 목화진딧물, 무궁화잎밤나방 그리고 점박이응애등이 피해가 심하여 방제를 요하는 주요해충이었다. 목화진딧물은 5월~6월, 무궁화잎 밤나방은 7월~8월, 점박이응애는 6월~8월에 밀도가 높았다. 무궁화에서 발견된 천적 및 병원성 미생물은 세균 1종, 병원성 곰팡이 3종, 노린재목 1종, 딱정벌레목 1종, 벌목 1종 파리목 2종, 응애강 1종 등 11종이 조사되었다. 목화진딧물 포식성 천적은 진디혹파리(Aphidoletes aphidimyza), 꽃등에류(Eristalis sp.), 무당벌레(Harmonia axyridis), 기생성 천적은 싸리진디벌(Aphidius gifuensis), 병원성 미생물은 Verticillium lecanii, Beauveria bassinan가 조사되었다. 무궁화잎밤나방 기생성 천적은 고치벌류(Cotesia sp.), 병원성 미생물은 Bacillus thuringiensis, B. bassiana, Meterhizium anisopliae가 확인되었다. 점박이응애 포식성 천적은 긴털이리응애류(Amblyseius sp.), 애꽃노린재류(Orius sp.)가 조사되었다.