• Korean journal of applied entomology
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• v.35 no.3
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• pp.232-237
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• 1996

Toxicity of 5 acaricides, 4 insecticides. and 6 fungicides to the twospotted spider mite, Tetranychus urticae Koch, and its predator Amblyseius womersleyi Schicha was assessed in a laboratory using a leaf disk bioassay. Dicofol was equally very toxic to aduly females of T. urticae and A. womersleyi, and caused 46% and 40% mortality of eggs of those two species, respectively. Adult females of A. womersleyi dipped in Abamectin solution showed low mortality(16.6%), while all T. urticae females died within 24 hours after dipping. Three ovicidal acaricides (Tetradifon, Clofentezine, and Hexythiazox) showed no mortality of predator eggs, but more than 90% mortality of T. urticae eggs. Four insecticides (Teflubenzuron, Triflumuron, Diflubenzuron, and Imidacloprid) and three fungicides (Propineb, Fenarimol, and Polyoxin-B captan) were non toxic to the A. womersleyi adult females. The other fungicides (Chlorothalonil, Nuarimol.Mancozeb, and Folpet) were a little toxic to adult females of the predator, showing$\leq$23.3% mortality, It may be suggested from these results that 4 insecticides, 4 acaricides, and 6 fungicides described could be incorporated into the integrated pest management system with A. womersleyi in apple orchard.

• Korean journal of applied entomology
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• v.37 no.2
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• pp.207-212
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• 1998

Tea field-collected populations of the tea red spider mite (Tetranychus kazawai Kishida) from five different locations in the southern region of Korea were assessed for resistance to seven acaricides using leaf spray method. There were considerable differences in susceptibility depending on the tested acaricides and the location from which the population was collected. The populations showing high resistance ratio of more than 20 with respect to certain acaricide were as follows: the Sungjun and Cheju populations to azocyclotin, tebufenpyrad, fenpyroximate, pyridaben, propargite, and fenpropathrin; the Haenam population to propargite and fenpyroximate; the Bosung population to propargite; the Youngam population to pyridaben. Therefore, the use of other alternative acaricides against the Sungjun and Cheju populations is needed. However, careful selection of the appropriate acaricide against the Haenam, Bosung and Youngam populations of the tea red spider mite might be maintained in effective control.

• Korean journal of applied entomology
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• v.49 no.3
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• pp.233-239
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• 2010

Seasonal occurrence and suitable time of control of Tetranychus kanzawai along with the control efficacy of the alternative use of natural predator and miticide was investigated in Rubus coreanus (Miquel). T. kanzawai appeared in late May with its peak between June and July, and decreased after August in R. coreanus. In Iksan, T. kanzawai estimates show peaks 2~4 times per year during the investigation periods from 2006 to 2008 in R. coreanus fields. Suitable time of control of T. kanzawai was in early to mid May. And control effects of T. kanzawai was improved with an alternated control plot, treating miticides in early-occurrence of T. kanzawai and then releasing the natural predator (Phytoseiulus persimilis Anthias-Henriot). Also, the yields of R. coreanus was highest in the alternated control plot of 638kg/10a compared to non-treatment of 559kg/10a.

• 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.

• The Korean Journal of Pesticide Science
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• v.13 no.3
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• pp.185-189
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• 2009

A monoterpenoid compound, benzylideneacetone (BZA), is a metabolite of an entomopathogenic bacterium, Xenorhabdus nematophila. Its primary biological activity is an inhibitor of phospholipase $A_2$, which catalyzes the committed step of biosynthesis of various eicosanoids that are critically important to mediate insect immune responses. When BZA was applied to two-spotted spider mite, Tetranychus urticae, it exhibited a dose-dependent mortality in leaf-disc assay. Subsequently BZA was tested against T. urticae infesting apples in a field orchard, in which it showed a significant control efficacy, which was not statistically different with that of a commercial acaricide. BZA also had significant antibacterial activities against three species of plant pathogenic bacteria when it was added to the bacterial cultures, in which it showed the highest inhibitory activity against a bacterial wilt-causing pathogen, Ralstonia solanacearum. The bacterial pathogen caused significant disease symptom to young potato plants. However, BZA significantly suppressed the disease occurrence. This study suggests that BZA can be used to develop a novel crop protectant to control mite and bacterial pathogen.

• The Korean Journal of Pesticide Science
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• v.11 no.1
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• pp.52-58
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• 2007

ALA (5-aminolevulinic acid) has been proposed as a tetrapyrrole-dependent photodynamic herbicide and insecticide by the action of the protoporphyrinogen IX oxidase (Protox IX). The present study was conducted to determine growth responses of plant and insects to ALA, biodegradable biopesticidal substance. In the paddy condition experiment, plant height and shoot fresh weight of barnyardgrass (Echinochloa crus-galli) was more reduced by ALA than rice plants, even though both plant species show great phytotoxicity. Hairy crabgrass (Digitaria sanguinalis), a monocot weed, was more sensitive to ALA at 5mM under upland condition when ALA applied on the foliage, compared with soybean (Glycine max) as a dicot crop. ALA solutions were tested for their insecticidal and larvicidal activities against Spodaptera exigua (Hubner) and Tetranychus urticae Koch. by foliar application and leaf-dipping method. The result showed higher insecticidal activity of ALA at 10mM and its mixture with insecticide luferon against S. exigua. Strongest insecticidal activity against T. urticae was observed from the ALA solution at 10mM 72 days after application. This results show that ALA solution had potent herbicidal and insecticidal activities against agricultural pests even though their activities were lower than those of synthetic pesticides.

• Horticultural Science & Technology
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• v.32 no.4
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• pp.434-439
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• 2014

This research was conducted to examine the effects of night interruption (NI) at different times on vegetative growth and flowering in Salvia splendens 'Salsa'. Plants were grown in a growth chamber under 9-h photoperiod (short-day, SD) or 9-h photoperiod plus NI with light intensity at $3-5{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ photosynthetic photon flux. The NI was applied at 18:00-22:00 HR (NI18), 22:00-02:00 HR (NI22), or 02:00-06:00 HR (NI02). The net photosynthetic rate under NI18, NI22, and NI02 increased by 0.33, 0.16, and $0.13{\mu}mol{\cdot}CO_2{\cdot}m^{-2}{\cdot}s^{-1}$, respectively, during the NI period. Dry weight, plant height, and the number of nodes under NI were not significantly different from those of the plants under SD. However, flowering was earlier by approximately 9.8 days, and the number of flowers increased to 138.7 in NI02 compared to 36.4 flowers under SD at 17 weeks after the treatment. Our results indicate that NI02 was the most effective treatment in promoting flowering. Although vegetative growth of salvia was not increased in response to the increased net photosynthesis, flowering was promoted. Under NI18, NI22, and NI02 treatments, 77.8, 88.9, and 100.0% of salvia plants flowered within 8 weeks, whereas 44.4% of the plants flowered within the same time under SD conditions.

• 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.

• Journal of Applied Biological Chemistry
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• v.60 no.2
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• pp.137-140
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• 2017

Agricultural pests, diamondback moth (Plutella xylostella), green peach aphid (Myzus persicae) and two-spotted spider mite (Teyranychus urticae), are becoming major pests in human dwellings in a variety of ways across the world. For management of these pests, the essential oils of Coriandrum sativum and Cinnamomum cassia prepared by steam distillation, hexane extraction and supercritical extraction methods were evaluated for the insecticidal effects. Using the contact bioassay, the $LD_{50}$ value of C. sativum oil by steam distillation extraction method was $30.59{\mu}g/cm^2$ against M. persicae adults. The $LD_{50}$ values of C. cassia oils prepared by steam distillation and hexane extraction methods were 5.96 and $4.64{\mu}g/cm^2$, respectively, against T. urticae adults, and $LD_{50}$ value of the essential oil by supercritical extraction method was $6.50{\mu}g/cm^2$ against M. persicae adults. This study showed that C. sativum and C. cassia oils could be an effective natural acaricide and insecticide against agricultural pests.

• The Korean Journal of Pesticide Science
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• v.6 no.4
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• pp.271-278
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• 2002

Methanol extracts from 420 samples of 173 plant species in 58 families were tested at 5000 ppm for their insecticidal and acaricidal activities against five economically important arthropod pests by spray method. The responses varied with arthropod pest species, plant species and plant tissue sampled. In a test with Nilaparvata lugens Stal, extracts from Zanthoxylum piperitum barks, Chamaecyparis obtusa leaf and Quercus salicina leaf showed potent insecticidal activity. With Plutella xylostella L., potent larvicidal activity was observed from extracts of Platycarya strobilacea wood, Meliosma myriantha barks, Sophora japonica leaf, Zanthoxylum piperitum barks, and Pinus thunbergii wood. Methanol extracts of Sophora japonica leaf and Zanthoxylum piperitum barks showed high insecticidal activity against Spodoptera litura. In a test with Tetranychus urticae Koch, extract from Carpinus coreana leaf, Firmiana simplex barks, Elaeagnus macrophylla leaf, Aralia elata leaf, Comus controversa barks and Chamaecyparis obtusa leaf exhibited strong acaricidal activity. As a naturally occurring pest control agent, Zanthoxylum piperitum barks could be useful as new insecticidal and acaricidal products against various arthropod pests.