• The Plant Pathology Journal
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• v.18 no.5
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• pp.251-258
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• 2002

A potyvirus was isolated from cultivated Iris plants showing leaf streak mosaic symptom. Reverse transcription and polymerase chain reaction (RT-PCR) product of 1 kb long which encoded partial nuclear inclusion B and N-terminal region of viral coat protein (CP) genes for potyviruses was successfully amplified with a set of potyvirus-specific degenerate primers with viral RNA samples from the infected leaves: The RT-PCR product was cloned into the plasmid vector and its nucleotide sequences were determined. The nucleotide sequence of a CDNA clone revealed that the virus was an isolate of Ornithogalum moseic virus (OrMV) based on BLAST search analysis and was denoted as OrMV Korean isolate (OrMV-Ky). To further characterize the CP gene of the virus, a pair of OrMV-specific primers was designed and used for amplification of the entire CP gene of OrMV-Kr, The virus was easily and reliably detected from virus-infected Iris leaves by using the RT-PCR with the set of virus-specific primers. The RT-PCR product of the CP gene of the virus was cloned and its sequences were determined from selected recombinant CDNA clones. Sequence analysis revealed that the CP of OrMV-Kr consisted of 762 nucleotides, which encoded 253 amino acid residues. The CP of OrMV-Ky has 94.1-98.0% amino acid sequence identities (20 amino acid alterations) with that of other three isolates of OrMV, Two NT rich potential N-glycosylation motif sequences, NCTS and NWTM, and a DAC triple box responsible for aphid transmission were conserved in CPs of all the strains of OrMV. The virus has 58.5-86.2% amino acid sequence identities with that of other 16 potyviruses, indicating OrMV to be a distinct species of the genus. OrMV-Ky was the most related with Pterostylia virus Yin the phylogenetic tree analysis of CP at the amino acid level. This is the first report on the occurrence of OrMV in Iris plants in Korea. Data in this study indicate that OrMV is found in cultivated Iris plants, and may have mixed infection of OrMV and Iris severe mosaic virus in Korea.

• Journal of Life Science
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• v.14 no.1
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• pp.67-71
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• 2004

Oriental melon vinegar was prepared by two stage fermentations of alcohol and acetic acid. In the alcohol fermentation using oriental melon residual products, alcohol content showed 7.43% in 17$^{\circ}$ brix of initial sugar concentration and 80 h of fermentation time. In the acetic acid fermentation using oriental melon alcohol, acidity showed 5.25% in 250rpm of agitation rate and 200 h of fermentation time. The cultivation esults of oriental melons using its vinegar are as follows. Quantity and quality of samples treated with 500, 1,000 and 2,000 times of oriental melon vinegar were higher than that of control : weight, quality, sugar content and goods production rate were higher to degree of 33∼42 g/piece, 370 ∼460kg/10a, 0.6∼.9$^{\circ}$ Brix, 2∼5%, respectively. Coods production yield of samples treated with 500, 1,000 and 2,000 times of oriental melon vinegar was higher (400∼610 kg/10a) than that of control. The results of control of powdery mildew on oriental melons using oriental melon vinegar as the diluted solution with 500 and 1000 times were identical for control value that used by agrochemical. Powdery mildew were exterminated by 2nd treatment of the diluted solution. In case of aphids, the diluted solution with 500, 1,000 and 2,000 times of oriental melon vinegar exterminated thoroughly by 2nd treatment.

• The Plant Pathology Journal
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• v.32 no.4
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• pp.321-328
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• 2016

We examined the effects of temperature on acquisition of Potato virus Y-O (PVY-O), Potato virus A (PVA), and Potato leafroll virus (PLRV) by Myzus persicae by performing transmission tests with aphids that acquired each virus at different temperatures. Infection by PVY-O/PVA and PLRV increased with increasing plant temperature in Nicotiana benthamiana and Physalis floridana, respectively, after being transmitted by aphids that acquired them within a temperature range of $10-20^{\circ}C$. However, infection rates subsequently decreased. Direct qRT-PCR of RNA extracted from a single aphid showed that PLRV infection increased in the $10-20^{\circ}C$ range, but this trend also declined shortly thereafter. We examined the effect of temperature on establishment of virus infection. The greatest number of plants became infected when N. benthamiana was held at $20^{\circ}C$ after inoculation with PVY-O or PVA. The largest number of P. floridana plants became infected with PLRV when the plants were maintained at $25^{\circ}C$. PLRV levels were highest in P. floridana kept at $20-25^{\circ}C$. These results indicate that the optimum temperatures for proliferation of PVY-O/PVA and PLRV differed. Western blot analysis showed that accumulations of PVY-O and PVA coat proteins (CPs) were lower at $10^{\circ}C$ or $15^{\circ}C$ than at $20^{\circ}C$ during early infection. However, accumulation increased over time. At $25^{\circ}C$ or $30^{\circ}C$, the CPs of both viruses accumulated during early infection but disappeared as time passed. Our results suggest that symptom attenuation and reduction of PVY-O and PVA CP accumulation at higher temperatures appear to be attributable to increased RNA silencing.

• Korean journal of applied entomology
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• v.25 no.2 s.67
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• pp.99-105
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• 1986

The green peach aphids(Myzus persicae) collected in a field had been successively selected by acephate(O, S-dimethyl N-acetyl phosphoroamidothioate) in the laboratory. The selected aphid strain in the 20th generation demonstrated relatively high resistance to acephate as well as relatively high cross-resistance to cypermethrin and oxydemeton-methyl, except pirimicarb. The different esterase isozymes with the strains were detected by the agarose gel electrophoresis and among the isozymes the band of ${\beta}-2$ was only specific for the acephate resistant strains.

• Korean journal of applied entomology
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• v.54 no.3
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• pp.247-255
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• 2015

The cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae) infests citrus orchards, causing sooty mold damage to the fruits. This study was conducted to investigate the colonizing route of A. gossypii in citrus orchards in a non-heating plastic-film house during the early season. The overwintering eggs of the aphids are frequently found on summer shoots of the citrus trees. The eggs were mostly those of Aphis citricola, without any A. gossypii when hatched. The colonization of citrus trees by alate A. gossypii in non-heating plastic-film houses was mainly observed twice, with advanced flight in late April and delayed flight in late May. The delayed flight was synchronized with the timing of the emergence of alate A. gossypii from the fundatrix generation in the holocyclic life cycle. During advanced flight in closed citrus orchards, alate A. gossypii were caught in yellow water traps installed in the fields, and the populations were found to originate from the surviving populations of the anholocyclic life cycle. Consequently, we concluded that citrus tree colonization with A. gossypii occurred during the advanced flight of the anholocyclic and the delayed flight of the holocyclic life cycle.

• Korean journal of applied entomology
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• v.49 no.4
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• pp.385-391
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• 2010

This study reports the results of natural enemy application against four insect pests on greenhouse sweet pepper in winter cropping system. Orius laevigatus ($3.3/m^2$) was released at two different times (Nov. 2005 & Feb. 2006) to control Frankliniella occidentalis, western flower thrips (WFT). Throughout the cropping season, the lowest level recorded of WFT was less than 2.0 individuals per yellow sticky trap. Amblyseius swirskii ($232.3/m^2$) was released four times (Nov. 2007 ~ Aug. 2008) to control Bemisia tabaci, tobacco whitefly (TWF). Until July 2008, TWF population had been suppressed lower than 6.6/trap. Phytoseiulus persimilis ($44.5/m^2$) was released seven times (Apr. 2008 ~ Aug. 2008) to control Tetranychus kanzawai, tea red spider mite (TRSM). As a result, TRSM population was suppressed lower than 1.7/1eaf. To control aphids, Aphidius colemani ($9.5/m^2$) was released seven times (Oct. 2004 ~ Jan. 2005), with the transplantation of banker plants ($5.5pot/660m^2$). As a whole, aphid's population has been successfully reduced to less than 2.0/leaf.

• Korean journal of applied entomology
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• v.49 no.4
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• pp.333-342
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• 2010

The possibility of commercializing the controlled release of chitosan carrier nano formulation was examined with mortalities and population increase rates of Aphis gossypii and Myzus persicae after treatment of 2 ${\alpha}$-cypermethrin nano type formulations of different chitosan carrier molecular weight (M.W. 3,000 and 30,000) and 2 etofenprox nano types of chitosan content (70% and 80%). After 14 days of treatment, ${\alpha}$-cypermethrin nano formulation showed over 40% mortality against A. gossypii. Therefore, it was confirmed that the insecticide release was controlled through chitosan carrier. Results of the investigation of insecticidal activity of ${\alpha}$-cypermethrin nano formulation showed there were no differences between nano types at 4 days after treatment. However, after 14 days, the population increase rate treated with chitosan M.W. 30,000 formulation was -0.037, much lower than that of M.W. 3,000 formulation with 0.231. The result exhibits that chitosan M.W. 30,000 formulation would be a suitable controlled release formulation. On the other hand, etofenprox formulations didn't show any significant insecticidal effect or persistency difference against both aphid species.

• Korean journal of applied entomology
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• v.56 no.4
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• pp.331-338
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• 2017

In the present study, we investigated the effects of two herbicide-resistant genetically modified rice (GM rice) varieties, Milyang 204 and Iksan 483, recently developed in Korea on non-target insects and a spider. No difference in host preferences of the English grain aphid Sitobion avenae and the brown planthopper Nilaparvata lugens were observed between GM rice and non-GM rice. Wolf spider Pirata subpiraticus, feeding on N. lugens reared on GM rice or non-GM rice, revealed no significant difference in body weight. P. subpiraticus, fed with N. lugens reared on Milyang 204, showed survival rates similar to that in P. subpiraticus fed with N. lugens reared on non-GM rice. However, P. subpiraticus feeding on N. lugens reared on Iksan 483 demonstrated significantly lower survival rates than that in P. subpiraticus feeding on N. lugens reared on Milyang 204 or non-GM rice. In addition, when larvae of the western honeybee Apis mellifera were supplied with Iksan 483 pollen, a significantly longer pupal period occurred, as compared with that of A. mellifera supplied with pollen of Milyang 204 or non-GM rice. As GM rice has negative effects on P. subpiraticus, which is an important predator in agricultural ecosystems, and on A. mellifera, which plays important roles in pollination and honey production, additional studies on risk assessment of GM rice should be conducted before releasing newly developed herbicide-resistant GM rice to the agricultural environment.

• 한국균학회소식:학술대회논문집
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• 2016.05a
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• pp.13-13
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• 2016

Insects constitute the largest and most diverse group of animals in the world. They also serve as the hosts or nutrient sources for an immense assemblage of pathogens, parasites, and predators. More than 700 fungal species from 100 genera have adopted an entomopathogenic lifestyle. Although entomopathogenic fungi were studied as only biocontrol agents against a variety of pests in various countries, it has been recently focused their additional roles in nature. They are antagonists to/against plant pathogens, endophytes, and possibly even plant growth promoting agents. The potential antimicrobial effect against fungal plant pathogens by an isolate of entomopathogenic fungi including Beauveria bassiana, Lecanicillium spp., and Isaria fumosorosea have been reported since late 1990s, but wasn't reported pathogenicity of the isolate against pests. Later, a Canadian Lecanicillium sp. isolate and L. longisporium isolated from Vertalec$^{(R)}$ showed simultaneous control effect against both aphid and cucumber powder mildew. Therefore, the antimicrobial activities of 342 fungi isolates collected from various regions and conditions in Korea were evaluated against plant pathogenic fungus Botrytis cinerea using dual culture technique on agar plate. As a result, 186 isolates (54.4%) shown the antifungal activity against B. cinerea. The culture filtrates of selected fungi completely suppressed the growth of the microorganisms, indicating that suppression was due to the presence of antimicrobial substances in the culture filtrate. Mode of action of these fungi against insect involves the attachment of conidia to the insect cuticle, followed by germination, cuticle penetration, and internal dissemination throughout the insect. During infection process, secreted enzymes, proteinous toxins, and/or secondary metabolites secreted by entomopathogenic fungi can be used to overcome the host immune system, modify host behavior, and defend host resources. Recently, secondary metabolites isolated from entomopathogenic fungi have been reported as potential bioactive substances. Generally, most of bioactive substances produced by entomopathogenic fungi have reported low molecular weight (lower than 1,000 g/mol) as peptide and, in contrast the high molecular weight fungal bioactive substances are rare. Most substances based on entomopathogenic fungi were shown antimicrobial activity with narrow control ranges. In our study we analyzed the antimicrobial substances having antagonistic effects to B. cinerea. Antimicrobial substances in our fungal culture filtrates showed high thermostability, high stability to proteolytic enzymes, and hydrophilicity and their molecular weights were differed from substance. In conclusion, entomopathogenic fungi showed pathogenicity against insect pests and culture filtrate of the fungi also shown to antimicrobial activity. In the future, we can use the entomopathogenic fungi and its secondary metabolites to control both insect pest control and plant pathogenic fungi simultaneously.

• Horticultural Science & Technology
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• v.34 no.3
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• pp.355-362
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• 2016

This study was carried out to investigate the effects of rain-shelter types on growth, and fruit quality of red pepper (Capsicum annuum, 'Kemmaru') cultured in paddy. Applied rain-shelter types were outfield (control), simple rain-shelter plastic house with 2 rows (2R), simple rain-shelter plastic house with 4 rows (4R), and perfect plastic house (House). The plant height was the highest in Houses treatment. There was no difference in leaf length and width among the rain-shelter treatments. The fresh and dry weight of red pepper was high in order of House > 4R > 2R > Control. The ASTA value is irregular tendency among the treatments. Hunter's color value 'a' and 'b' was not different from among the treatments. Phytophthora blight, powdery mildew, bacterial spot were not occurred in all of treatments, and Anthracnose was only occurred in control. Mite, Microcephalothrips abdominalis, and Bemisia tabaci were not occurred in all of treatments, and aphid, Helicoverpa assulta, and virus were occurred all of treatments as same degree. Our results will provide rain-shelter cultivation of red pepper can be increase dry yield and decrease disease and insects.