• 한국환경농학회지
• /
• 제37권2호
• /
• pp.125-134
• /
• 2018

BACKGROUND: Green peach aphid (Myzus persicae) is an insect pest that significantly affects crop production. A number of pesticides have been used for aphid control, but their concerns on insect resistance and food safety have required alternative methods for pest management. In an effort to find for an alternative approach to aphid control, we screened plants extracts and examined their potentiality as insecticidal bio-resources. METHODS AND RESULTS: Two hundred and ninety eight plant extracts were examined for insecticidal activity against the aphid, and the best candidate among them was chosen for further study. The extracts from Cinnamomum camphora was determined to be the best candidate exhibiting insecticidal activity more than 60% at a level of $1,000{\mu}g/mL$. GC/MS analyses detected camphor, borneol, 4-terpineol, ${\alpha}$-terpineol and caryophyllene oxide as major compositions from the extracts obtained by hydrodistillation. Caryophyllene oxide exhibited the highest insecticidal activity with a $LC_{50}$ value of $237{\mu}g/mL$. Camphor lowered significantly the $LC_{50}$ value of caryophyllene oxide and increased largely its concentration in aphid, suggesting that camphor played a role in enhancing the insecticidal activity of caryophyllene oxide. CONCLUSION: This study suggested that camphor and caryophyllene oxide may be used as an insecticidal bio-resource for insect control against green peach aphid.

• BMB Reports
• /
• 제38권1호
• /
• pp.41-48
• /
• 2005

In this study we developed the transposon-mediated shuttle vector 'Hanpvid', which composed of HaNPV (Heliothis armigera nuclear polyhedrosis virus) genomic DNA and a transposon cassette from Bacmid of Bac-to-Bac system. Hanpvid replicates in E. coli in the same way as Bacmid and retains infective function in cotton bollworm cells (Hz-AM1). Using Hanpvid we constructed a recombinant virus, which could infect Hz-AM1 cells and generate recombinant HaNPV (rHa-Bar) containing the barnase gene, a ribonuclease gene from Bacillus amyloliquefaciens. Since the expression vector carrying barnase gene cannot replicate in the absence of barstar, a specific inhibitor of barnase, we constructed a new cotton bollworm cell line (AM1-NB) using the marker rescue method. In AM1-NB barstar was integrated into the cellular chromosome to sustain the replication of rHa-Bar. To screen out recombinant HaNPV for potential use as biopesticide, Hz-AM1 and AM1-NB cell lines were infected with rHa-Bar, respectively. The results obtained indicate that Viral progenies in AM1-NB were 23 and 160 times greater than those in Hz-AM1 48 h and 72 h after infection, respectively. With additional insertion of the polyhedron gene from AcNPV (Autographa californica nuclear polyhedrosis virus) into the Hanpvid genome, rHa-Bar regained the polyhedron phenotype and its pest-killing rate greatly improved. Toxic analysis showed that the lethal dosages ($LD_{50}$) and the lethal time(s) ($LT_{50}$) of rHa-Bar were reduced by 20% and 30%, respectively, compared to wt-HaNPV in the third instar larvae of cotton bollworm. This study shows that in AM1-NB barnase can be effectively produced and used as pest-killing agent for the biological control of cotton pests.

• 한국작물학회지
• /
• 제52권2호
• /
• pp.183-197
• /
• 2007

Field trial was conducted at the Research Farm of the Katsina State Agricultural and Rural Development Authority during the farming season of 2004 with a view to evaluate/determine the efficacy of some selected plant-derived biopesticides against the insect pests of cowpea as well as their effect on yield. The variety of the cowpea used was IT86D-719 and the plant derived biopesticides evaluated during the trial were chilli pepper, garlic, ginger, neem, sweetsop and tobacco. The experimental field was ploughed, harrowed and thereafter ridged before the commencement of the 2004 planting season. A total of twenty one (21) experimental plots were demarcated and arranged into seven treatment plots. The size of each plot was $5m{\times}4m$ while interspaces between adjacent plot and blocks were 1m and 2m, respectively. Results of the experiments showed that all the plant-derived biopesticide treatments were significantly (p>0.05) better than control treatment. The order of effectiveness of the treatments was tobacco (80-90%), sweetsop (75-85%), garlic (70-80), neem (72-78%), chilli pepper (60-70%) and ginger (30-50%). Furthermore, yield result corresponded positively with the effectiveness of the treatments. Results of the present finding suggest the use of tobacco, sweetsop and garlic as promising biopesticides in the control of cowpea insect pests.

• Journal of Microbiology and Biotechnology
• /
• 제14권5호
• /
• pp.1057-1062
• /
• 2004

The entomopathogenic bacterium Bacillus thuringiensis is the most widely used biopesticide. Insecticidal proteins, coded by genes located in plasmids, form typical parasporal, crystalline inclusions during sporulation. We isolated a Bacillus thuringiensis strain having insecticidal activity against larvae of the house fly (M. domestica) from the soils at a pig farm in Korea, and named it Bacillus thuringiensis SM. The culture filtrate from Bacillus thuringiensis SM showed strong lethality (83.3%) against M. domestica larvae. The parasporal crystal is enclosed within the spores' outermost envelope, as determined by transmission electron microscopy, and exhibited a bipyramidal form. The crystal proteins of strain SM consisted of five proteins with molecular weights of approximately ~130, ~80, ~68, ~42, and ~27 kDa on a 10% SDS-PAGE (major band, a size characteristic of Cry protein). Examination of antibiotic resistance revealed that the strain SM showed multiple resistant. The strain SM had at least three different plasmids with sizes of 6.6, 9.3, and 54 kb. Polymerase chain reactions (PCRs) revealed the presence of cry1, cry4A2, and cry11A1 genes in the strain SM. The cry1 gene profile of the strain SM appeared in the three respective products of 487 bp [cry1A(c)], 414 bp [cry1D], and 238 bp [cry1A(b)]. However, the strain SM has not shown the cry4A2 md cry11A1 genes. In in vivo toxicity assays, the strain SM showed high toxicity on fly larvae (M. domestic) [with $LC_{50}$ of 4.2 mg/ml, $LC_{90}$ of 8.2 mg/ml].

• Journal of Microbiology and Biotechnology
• /
• 제13권1호
• /
• pp.50-56
• /
• 2003

A freshwater bloom-forming cyanobacterium, Microcystis aeruginosa, and local soil isolate Scytonema sp. strain BT 23 were demonstrated to contain biotoxic secondary metabolites with pesticidal and mosquito larvicidal activities. A purified toxic constituent from M aeruginosa showed an absorption maximum at 230 nm and its toxicity symptoms, Rf value on TLC, and retention time observed ill an HPLC analysis were similar to those of the hepatotoxic heptapeptide microcystin-LR. The bioactive constituent of the Scytonema sp. was less polar in nature and exhibited two peaks at 240 and 285 m. When applied to two cruciffrous pests, Pieris brassicae and Plutella flostella, the crude extracts and toxic principles from the two cyanobacteria showed significant antifeedant activity in a no-choice bioassay, and at higher concenuations exhibited contact toxicity to the insect larvae. The purified toxin from M. aeruginosa was found to be more effective and produced 97.5 and $92.8\%$ larval mortality in the two pests, fo11owing 2 h of toxin treatment at a concentration of $25{\mu}g$ Per leaf disc (2.5 cm dia.). Meanwhile, similar treatment with the purified toxin from Sytonema sp. stain BT 23 only produced 73 and $78\%$ mortality in the two pests. The cyanobacterial constituents also showed significant activity against Culex and Anopheles larvae. The M. aeruginosa toxin ($20{\mu}g\;ml^-1$) caused 98.2 and $88.1\%$ mortality in the Culex and Anopheles larvae, respectively, while the purified toxin from the Sytonema sp. was less toxic and only produced a 96.3 and $91.2\%$ mortality, respectively, at a much higher concentration ($40{\mu}g\;ml^-1$). Accordingly, the current results point to certain hitherto unknown biological properties of cyanobacterial biotoxins.

• Weed & Turfgrass Science
• /
• 제6권1호
• /
• pp.1-10
• /
• 2017

생물제초제의 이용은 농업에서 지속성을 향한 중요한 단계로 활용 될 수 있을 것이다. 유기농업 및 종합잡초관리는 보존농업에서 합성제초제와는 다르게 한 종류의 잡초관리기술에 의존하지 않아야 하며, 생물제초제는 다른 잡초관리기술과 동시에 평가되는 것이 바람직할 것이다. 우리나라 실정에 적합한 세균 및 진균으로부터 유래한 상업용 생물제초제를 선발하여 유기농업 농가에서 영농부가가치가 높은 고소득 작물을 대상으로 생물제초제 실용화 가능성을 검토할 가치가 있을 것이다. 또한 유기영농 과수원에서 비선택적으로 잡초를 방제하기 위하여 상업용으로 시판되는 옥수수 글루텐 가루 제제와 각종 식물정유 제제 등 제품에 대한 실용화 연구가 필요할 것이다.

• 한국약용작물학회지
• /
• 제28권1호
• /
• pp.38-46
• /
• 2020

Background: Although Sancho (Zanthoxylum schinifolium Siebold & Zucc) oil has traditionally been used for its antibiotics properties, there is currently a lack of scientific evidence regarding its biological activities. In this study, we investigated the antimicrobial and antioxidant activities of Sancho oil against food-hazardous microorganisms, phytopathogens, and dermatophytes. Methods and Results: We investiated the antimicrobial activity of Sancho oil against 11 food-hazardous microorganisms, nine phytopathogens, and six dermatophytes. The Sancho oil was found to show the strongest antibacterial activity against Shigella flexneri and Listeria spp. Sancho oil also showed high antifungal activity against plant pathogens, particularly Fusarium oxysporum, and showed antimicrobial activity against dermatophytes such as Trichophyton rubrum, Microsporum canis and Candida albicans. The antioxidant activity of Sancho oil was measured using the DPPH method, and was found to be stronger than that of unrefined oil. Moreover, this activity increased with increasing oil concentration. Conclusions: We found that Sancho oil showed differing antimicrobial activities against food-hazardous microorganisms, dermatophytes, and plant pathogens. The antimicrobial activity spectrum of Sancho oil was not broad and varied among microbial strains. On the basis of our findings, we consider that Sancho oil could be used an antibacterial material for food-borne S. flexneri and Listeria spp., a biopesticide for Fusarium spp., and a treatment for dermatophytes such as T. rubrum.

• 한국응용곤충학회지
• /
• 제56권3호
• /
• pp.289-294
• /
• 2017

오리엔탈과실파리(Bactrocera dorsalis)는 주요 검역 대상으로 지정된 해충이다. 이 해충에 대한 고감도 모니터링과 진단 기술이 초기 방역 처리에 요구된다. 본 연구는 오리엔탈과실파리를 유인하여 치사시킬 목적으로 메틸유제놀과 생물농약을 혼합한 왁스형 방출기를 제작하였다. 본 연구는 또한 5종의 주요 검역 과실파리(오리엔탈과실파리, 오이과실파리, 퀸즐랜드과실파리, 말레이시아과실파리, 지중해과실파리)에 대한 PCR 진단프라이머를 개발하였다. 이상의 모니터링용 왁스방출기과 분자진단기술을 말레이시아 코타키나발루 지역에서 실증 시험하였다.

• The Plant Pathology Journal
• /
• 제28권1호
• /
• pp.68-74
• /
• 2012

Biocontrol microbes have mainly been screened among large collections of microorganisms $via.$ nutrient-rich $in$ $vitro$ assays to identify novel and effective isolates. However, thus far, isolates from only a few genera, mainly spore-forming bacilli, have been commercially developed. In order to isolate field-effective biocontrol microbes, we screened for more than 200 oligotrophic bacterial strains, isolated from rhizospheres of various soil samples in Korea, which induced systemic resistance against the soft-rot disease caused by $Pectobacterium$ $carotovorum$ SCC1; we subsequently conducted in $planta$ bioassay screening. Two oligotrophic bacterial strains were selected for induced systemic disease resistance against the $Tobacco$ $Mosaic$ $Virus$ and the gray mold disease caused by $Botrytis$ $cinerea$. The oligotrophic bacterial strains were identified as $Pseudomonas$ $manteilii$ B001 and $Bacillus$ $cereus$ C003 by biochemical analysis and the phylogenetic analysis of the 16S rRNA sequence. These bacterial strains did not exhibit any antifungal activities against plant pathogenic fungi but evidenced several other beneficial biocontrol traits, including phosphate solubilization and gelatin utilization. Collectively, our results indicate that the isolated oligotrophic bacterial strains possessing induced systemic disease resistance could provide useful tools as effective biopesticides and might be successfully used as cost-effective and preventive biocontrol agents in the field.

• Journal of Microbiology and Biotechnology
• /
• 제17권4호
• /
• pp.547-559
• /
• 2007

Bacillus thuringiensis (Bt) was first described by Berliner [10] when he isolated a Bacillus species from the Mediterranean flour moth, Anagasta kuehniella, and named it after the province Thuringia in Germany where the infected moth was found. Although this was the first description under the name B. thuringiensis, it was not the first isolation. In 1901, a Japanese biologist, Ishiwata Shigetane, discovered a previously undescribed bacterium as the causative agent of a disease afflicting silkworms. Bt was originally considered a risk for silkworm rearing but it has become the heart of microbial insect control. The earliest commercial production began in France in 1938, under the name Sporeine [72]. A resurgence of interest in Bt has been attributed to Edward Steinhaus [105], who obtained a culture in 1942 and attracted attention to the potential of Bt through his subsequent studies. In 1956, T. Angus [3] demonstrated that the crystalline protein inclusions formed in the course of sporulation were responsible for the insecticidal action of Bt. By the early 1980's, Gonzalez et al. [48] revealed that the genes coding for crystal proteins were localized on transmissible plasmids, using a plasmid curing technique, and Schnepf and Whiteley [103] first cloned and characterized the genes coding for crystal proteins that had toxicity to larvae of the tobacco hornworm, from plasmid DNA of Bt subsp. kurstaki HD-1. This first cloning was followed quickly by the cloning of many other cry genes and eventually led to the development of Bt transgenic plants. In the 1980s, several scientists successively demonstrated that plants can be genetically engineered, and finally, Bt cotton reached the market in 1996 [104].