• Korean journal of applied entomology
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• v.47 no.1
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• pp.59-64
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• 2008

Insecticidal activity of 20 plant species against adults of Myzus persicae, female adults of Tetranychus urticae, and $2^{nd}\;or\;3^{rd}$ instar larvae of Plutella xylostella was evaluated in this study. Thirteen plant extracts showed over 80% acaricidal activity to T. urticae at the concentration of 1 %, while Capsicum annuum (hot-pepper seed), Inula helenium, and Acorus calamus revealed 82.8-86.2% acaricidal activities at 0.5%. Insecticidal activities of the plant extracts to M. persicae and P. xylostella were relatively low compare to the mite. Among the plant extracts, C. anuum and Brassica juncea revealed 48.6% and 42.9% respectively insecticidal activities to the aphid at the concentration of 0.5%. Extracts of C. anuum and Jeffersonia dubia provided 55% and 50% insecticidal activity against P. xylostella at 1%. And, the highest antifeeding activity of the insect was observed in the J. dubia extract as 79.4%. Results indicated that some plant extracts including hot pepper seed could be used as potential botanical pesticides for organic farming.

• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.131-136
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• 2011

Synthesis of N-(1H-benzimidazol-2-yl)-6-substituted-1,3-benzothiazol-2-amines and 6-substituted-N-(4,5-dihydro-1H-imidazol-2-yl)-1,3-benzothiazol-2-amines by the reaction of substituted 2-aminobenzothiazoles with carbon disulphide and methyl iodide followed by the reaction with o-phenylene diamine/ethylene diamine are reported. All the synthesized compounds were characterized by elemental analysis, IR spectra and $^1H$ NMR spectral studies. The potent antibacterial and entomological (antifeedant, acaricidal, contact toxicity and stomach toxicity) activities of the synthesized compounds were investigated.

• Journal of Applied Biological Chemistry
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• v.62 no.1
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• pp.19-23
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• 2019

The chemical compositions of the essential oil of Valeriana officinalis roots obtained by steam distillation method were analyzed by GC-MS. The 16 constituents were identified in the V. officinalis oil, and the most abundant compounds were patchouli alcohol (18.69%) and ${\beta}$-gurjunene (15.26%). Acaricidal effects of the V. officinalis oil were evaluated against Tyrophagus putrescentiae, Haemaphysalis longicornis larva and H. longicornis nymph by contact bioassay. The $LD_{50}$ values against T. putrescentiae, H. longicornis larva and H. longicornis nymph were 28.01, 178.26 and $207.98{\mu}g/cm^2$, respectively. Agar disc diffusion bioassay showed the antibacterial activity of the V. officinalis oil against foodborne pathogens, especially L. monocytogenes. These results showed that the essential oil of V. officinalis roots derived from USA has a potential for development as acaricide and antimicrobial.

• Korean journal of applied entomology
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• v.47 no.3
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• pp.287-292
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• 2008

Repellent and acaricidal activities of eucalyptus oil, permethrin, and DEET against Leptotrombidium pallidum larvae, which are a vector transmitting tsutsugamushi disease, were evaluated under laboratory conditions using a filter paper impregnated method. The $LD_{50}$ values of eucalyptus oil and DEET were 0.025 and 0.018 $mg/cm^2$, respectively while that of permethrin was higher than 0.2 $mg/cm^2$. In the repellency test of these materials at 6.14 $mg/cm^2$, eucalyptus oil gave complete repellency, and the larvae crossed the treated zone killed. But permethrin showed 60% repellency at 9.20 $mg/cm^2$ and the mites croosed the zone were not killed. The percent repellency of DEET at 0.53 $mg/cm^2$ was 8.3 and 2.8 times higher than that of permethrin and eucalyptus oil, respectively. The acaricidal activities of emulsifiable concentrates-pump sprayers containing the eucalyptus oil as an active ingredient were assayed. The emulsifiable concentrates containing 1% and 3% eucalyptus oil showed weak mortality at 1 hour after treatment, while all ones containing more than 6% oil produced 100% activity against L. pallidum larvae. The mortality also increased as exposure time to the concentrates increase. These results suggest that the potential of eucalyptus oil highly expected to be used as a control or repellent agent against L. pallidum larvae may be very high.

• Korean Journal of Poultry Science
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• v.47 no.1
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• pp.21-27
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• 2020

This study intended to investigate the effects of slaked lime and ethanol on poultry red mites (PRM) in the coops of laying hen. Three experiments were conducted to this effect. The first used untreated hydrated lime as a control and 10% and 20% aqueous solutions of hydrated lime were used as treatments. The second experiment used 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% ethanol solutions as treatments. The third experiment used hydrated lime in two distinct concentrations (10% and 20%) and 30%, 40%, and 50% ethanol solutions mixed to yield a total of 6 (2 × 3) treatments. All treatments were tested three times each. In the first experiment, the PRM killing rates were 74.0% and 92.3% when treated with 10% and 20% hydrated lime solutions, respectively. The acaricidal activity of the control sample was 0%. In the second experiment, the lowest value was 1.67% for the 30% ethanol solution, 8.33% for the 40% solution, and 7.47% for the 50% solution. The acaricidal activities of the 60% and 70% solutions were 42.4% and 84.7%, respectively. A 100% acaricidal activity was observed in dilutions above 80% (P<0.05). In the third experiment, the PRM killing effect of the hydrated lime + ethanol mixture was 100% in all treatments. In conclusion, after taking into consideration the economical and safety factors, a mixture of 10% hydrated lime solution and 30% ethanol is considered to be a suitable candidate for controlling PRM.

• Korean journal of applied entomology
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• v.32 no.2
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• pp.123-128
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• 1993

The comparative toxicities of selected acaricides against the twospotted spider mite, Tetranychus urticae, were investigated. The ovicidal and adulticidal activities of selected acaricides were examined under different developmental stages. Fenpyroximate showed high activity throughout all developmental stages of mites. The oviposition inhibition effect of fenpyroximate was more highly effective than that of cyhexatin. At 100 ppm concentration, the effect of fenpyroximate on the residual oviposition inhibition was persistant during 25 days with 85% level, while the effect of cyhexatin gradually decreased, and then decreased to 40% at 25 days after treatment. Fenpyroximate at 100 ppm showed 100% knockdown activity within 3 hour while cyhexatin showed only 91% knockdown activity within 24 hours after treatment. Most of selected acaricides had no systemic activity, but metasystox at 800 ppm had 100% of the systemic activity at 24 hours after treatment. For the influence of temperature on the activity, fenpyroximate showed stable activity and no temperature-dependent in comparison with other selected adaricides.

• Korean Journal of Veterinary Service
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• v.32 no.1
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• pp.87-92
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• 2009

The avoidance of the allergen of the house dust mite is one of the challenges to reduce and treat the symptoms of allergic diseases. Accordingly, various acaricidal agents are being used to kill the mite, but just killing it leaves the remains of it, which still act as the allergen. Therefore expelling the mite is thought as best policy to avoid the mite allergen. For this, some materials have been applied to repellent agents against the mite. Among them, a material with natural origin, known as the phytoncide, is being used for its repellent activity, as well as for its benefits for health. In this experiment, essential oils extracted from Korean white pine (Pinus koreaiensis S. et Z.) and hinoki cypress (Chamaecyparis obtusa), which are widely used as the source of phytoncide products, are studied for demonstration of the repellent effect against the house dust mites, Dermatophagoides farinae and D. pteronyssinus. Direct contact method was used to evaluate the repellent effect (%). And the results suggest the oils have a significant effect enough to be used as a source of repellent agent. For the repellent effect, the most effective concentration was $0.5{\mu}l/cm^2$ at 45 minutes both in the white pine and the hinoki oil.

• Korean journal of applied entomology
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• v.51 no.1
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• pp.47-58
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• 2012

Effect of a new crop protectant 'Bt-Plus' on natural enemies was analyzed in this study. Tested natural enemies included two parasitic species of $Aphidius$ $colemani$ and $Eretmocerus$ $eremicus$, and four predatory species of $Harmonia$ $axyridis$, $Orius$ $laevigatus$, $Amblyseius$ $swirskii$, and $Phytoseiulus$ $persimilis$. 'Bt-Plus' was formulated by combination of three entomopathogenic bacteria ($Xenorhabdus$ $nematophila$ (Xn), $Photorhabdus$ $temperata$ subsp. $temperata$ (Ptt), $Bacillus$ $thuringiensis$ (Bt)) and bacterial metabolite (BM). All three types of 'Bt-Plus' showed significantly higher toxicities against fourth instar $Plutella$ $xylostella$ larvae than Bt single treatment. Two types of bacterial mixtures ('Xn+Bt' and 'Ptt+Bt') showed little toxicity to all natural enemies in both contact and oral feeding assays. However, 'BM+Bt' showed significant toxicities especially to two predatory mites of $A.$ $swirskii$ and $P.$ $persimilis$. The acaricidal effects of different bacterial metabolites were evaluated against two spotted spider mite, $Tetranychus$ $urticae$. All six BM chemicals showed significant acaricidal effects. The BM mixture used to prepare 'Bt-Plus' showed a high acaricidal activity with a median lethal concentration at 218.7 ppm (95% confidence interval: 163.2 - 262.3). These toxic effects of bacterial metabolites were also proved by cytotoxicity test against Sf9 cells. Especially, benzylideneacetone, which was used as a main ingredient of 'BM+Bt', showed high cytotoxicity at its low micromolar concentration.

• Korean Journal of Organic Agriculture
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• v.27 no.3
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• pp.327-339
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• 2019

The differential susceptibility of the two spotted spider mite, Tetranychus urticae and its predator, Phytoseiulus persimilis against extracts of Gleditsia japonica var. koraiensis, Camellia sinensis, Cinnamomum cassia, Lantana camara and their mixtures was evaluated. The plant extracts tested were much less toxic to P. persimilis than to T. urticae. The plant extracts tested had little effect on the survival of P. persimilis adult females. Moreover, reproduction of P. persimilis adult females and eclosion of eggs deposited by treated predators were not seriously affected. The treatments of the plant extracts tested showed no serious toxic effect on P. persimilis eggs and exhibited 84~100% hatchability. The treatments with mixtures 3 and 1 were effective against the adult females of T. urticae and yielded 76.0% and 72.7% adulticidal activity at 7 days after treatment, respectively. The treatment of mixture 2 revealed 63.3% adulticidal activity. Generally, the acaricidal activity of the individual treatment of each plant extract was lower than the mixtures. The adult females of T. urticae treated with mixtures 3 and 1 produced only 29.5~31.3% as many eggs as the control females did. All the plant extracts tested exhibited no noticeable toxic effect to the eggs of T. urticae. These results suggest that mixtures 3 and 1 might be used for the control of T. urticae, and expected to be promising candidates for use in integrated mite management program with P. persimilis.

• Journal of Oral Medicine and Pain
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• v.35 no.1
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• pp.19-29
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• 2010

Phytoncide, essential oil of trees, has microbicidal, insecticidal, acaricidal, and deodorizing effect. The present study was performed to examine the effect of phytoncide on Candida albicans, which is a commensal colonizer of the mucous membranes but has become an opportunistic pathogen. C. albicans was incubated with or without phytoncide extracted from Hinoki (Chamaecyparis obtusa Sieb. et Zucc.; Japanese cypress) and then changes were observed in its optical density, cell viability and morphology. As concentrations of phytoncide added to the culture medium increased, optical density and cell viability of C. albicans decreased. Minimum inhibitory concentration of phytoncide for C. albicans was observed to be 0.25%, and minimum fungicidal concentration was 0.5%. Numbers of morphologically atypical cells with electron-dense cytoplasm and granules and increased with increasing concentration of the phytoncide. At higher concentrations of phytoncide, compartments and organelles in the cytoplasm became indistinguishable. The overall results indicate that the phytoncide used for this study has a strong antimicrobial activity against C. albicans. Therefore, the phytoncide may be used as a candidate for prevention and therapeutic agent against oral candidiasis.