• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.376-382
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• 2012

Environment-friendly agro-materials are are likely to be preferred to chemical insecticides recently. For this reason, many studies are conducted to develop environment-friendly insecticides containing natural materials. This study was also conducted so as to assess ecotoxicity for Emulsifiable concentrate (EC) containing 30% of garlic extract or two plant essential oils (Zanthoxylum, Lemongrass) expected to prevent from pests and be used for agro-materials. Target species used to assess acute toxicity were invertebrate (Daphina magna), fish (Oryzias latipes), honeybee (Apis mellifera L.) and earthworm (Eisenia fetida). The $EC_{50}$ values for of garlic extract 30% EC, Zanthoxylum oil 30% EC and lemongrass oil 30% EC to Daphina magna were 3.3, 10, and $10mg\;L^{-1}$, respectively. The category of garlic extract 30% EC was moderately toxic, while those of Zanthoxylum oil 30% EC and lemongrass oil 30% EC were slightly toxic according to standard of USEPA. $EC_{50}$ for both of Zanthoxylum oil 30% EC and lemongrass oil 30% EC were more than $10mg\;L^{-1}$ then they were considered as slightly toxicity. In case of acute toxicity test to fish, $LC_{50}$ of garlic extract 30% EC was $3.3mg\;L^{-1}$. Zanthoxylum oil 30% EC and lemongrass oil 30% EC indicated $LC_{50}$ > $10mg\;L^{-1}$. Classification of acute toxicity to all test substances was in Korea criteria. Acute contact and oral toxicity test to Honeybee were conducted. As a result, $LD_{50}$ of all test substances were more than 100 a.i. ${\mu}g\;bee^{-1}$ in the acute contact test while $LD_{50}$ of garlic extract 30% EC was 4.4 a.i. ${\mu}g\;bee^{-1}$ and $LD_{50}$ of Zanthoxylum oil 30% EC and lemongrass oil 30% EC were more than 100 a.i. ${\mu}g\;bee^{-1}$. In case of acute toxicity test to earthworm, $LC_{50}$ of garlic extract 30% EC, Zanthoxylum oil 30% EC and lemongrass oil 30% EC were 267, 592, and $430mg\;kg^{-1}$, respectively. In conclusion, if the safety for earthworm is confirmed, these substances are expected to be use for environment-friendly insecticide materials with low risk against ecosystem and contribute to developing environment-friendly agro-materials.

• Korean Journal of Ecology and Environment
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• v.43 no.2
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• pp.212-220
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• 2010

Effects of sediment and toxic cyanobacterium Microcystis aeruginosa on feeding behaviors of an omnivorous fish, gold fish (Carassius auratus) were examined in laboratory and in situ mesocosm. Laboratory feeding experiments were performed in small aquaria (7 L) with cyanobacterial blooms (mainly M. aeruginosa) under the condition of sediments and no-sediments, and toxic (NIES-298) and non-toxic M. aeruginosa (NIES-101). In situ feeding experiments were conducted at the shore of eutrophic lake (Lake Ilgam, Seoul) in the mid-July, 2005. Results showed that fish introduction decreased the concentration of Chlorophyll-a (Chl-a) at higher rate in no sediment-containing aquaria. In contrast, there was a drastic increase of Chl-a in the sedimentcontaining aquaria. Fish effectively removed the M. aeruginosa cells without algal toxin (microcystin). Fish also selectively removed the large size Chl-a (>$50{\mu}m$), although all kinds of nutrients were increased after fish introduction, especially ammonia. Our results indicate that the strategic introduction of domestic omnivores Carassius auratus, to control cyanobacterial bloom in eutrophic lake will negatively play in the water quality improvement via a sediment disturbance and a density-dependent digestion.

• Korean journal of applied entomology
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• v.42 no.2
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• pp.145-152
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• 2003

Field application of the entomopathogenic nematode, Steinernema carpncapsae, is limited by its susceptibility to UV irradiation and desiccation especially at leaf spray control. This study was conducted to develop the control technique using alginate biocapsulation of the nematodes against the beet armyworm, Spodoprera exigua and the tobacco cutworm, Sp. litura that are normally infesting hosts above ground level. The alginate capsules including infective juveniles gave significant feeding toxicities to the larvae of the two lepidopteran species. The lethality followed a typical sigmoid dose-mortality pattern with increase of the nematode densities embedded in the capsules. Moisture content in the capsule was critical to the survival of the infective juveniles. More than 80% nematodes could survive above 10% moisture content remained in the capsule. Remaining moisture content within the capsule was dependent on relative humidity, ambient temperature, and capsule size, but not on citric acid reaction time during capsule formation. More than 80% of infective juveniles in the alginate capsules could survive in distilled water at 15$^{\circ}C$ for 60 days. When these nematode capsules containing welsh onion extract as another phagostimulant were applied on the 3rd instar larvae of Sp. exigua infesting peanut plants, they resulted in about 90% control efficacy. These results indicate that the alginate capsulation can be used for leaf-spray agent of the entomopathogenic nematodes as well as for improved storage purpose.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.3
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• pp.176-178
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• 2000

The toxicity of muscle in pufferfish, Tikifugu vermicularis radiatus is known to be weak. However, no food poisoning has reported in this species although market consumption has been relatively high in Korea, especially on western coastal area. It presumes that there could be different toxicity in fish muscle of fresh and frozen specimens. In this regard, the frequency of toxic fish, the toxicity level in fresh and frozen fish as well as highest toxicity ann average toxicity were investigated. From the results, weak toxicity was detected in frozen fish muscle whereas no toxicity was measured in fresh fish. According to this, it is suggested that the toxicity of frozen and fresh fish must be tested simultaneously when tonicity of pufferfish is investigated. The above results implicate that toxicity of pufferfish may be due to the phsyical treatment such as freezing or thawing process.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.3
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• pp.52-64
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• 2008

Aged sewage sludge with food waste leachate sludge or paper mill sludge was fed to earthworm (Eisenia fetida) populations and the effect of it on feeding and growth rate of earthworm population was investigated. Feeding rate of earthworm population on sewage sludge aged with food waste leachate sludge for 30 days was higher than that aged for 10 and 20 days. At 90 days after feeding, the density of earthworm population decreased regardless of aging period. And earthworm population growth to next generation was blocked by sewage sludge. The feeding rate and the density of earthworm population aged with paper mill sludge for 20 days were higher than that on sewage sludges aged for 10 and 30 days. Until 90 days after feeding, the density of earthworm population increased regardless of aging period of sewage sludge, however, since then decreased. There were comparatively higher feeding rate and growth rate of earthworm population on the sewage sludge which had been mixed with paper mill sludge and aged for 20 days, which rendered the probable pretreating method for vermicomposting sewage sludge.

• Journal of Environmental Impact Assessment
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• v.26 no.3
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• pp.207-216
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• 2017

Several bioassays have been performed for assessment of the impact of polluted sediments. The direct exposure method using sediments is limited by difficulty controlling feeding and its effects on organisms. Furthermore, only macro-organisms and benthic organisms are used. To evaluate the potential application of sediment elutriate as a complementary strategy for impact assessment, copepods, small organisms with a short life cycle, were exposed to sediment elutriates, and several end-points were measured. As a result, sediment elutriates prepared from polluted sites caused growth retardation in marine copepods. In terms of molecular biomarkers, antioxidant-related and chaperone protein gene expression levels were increased in a dose- and time-dependent manner. Thus, we suggest that sediment elutriate tests can provide an effective alternative for toxicity assessment using whole sediment samples. Further studies are required to obtain sufficient data for future applications.

• 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.

• The Korean Journal of Pesticide Science
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• v.12 no.3
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• pp.229-235
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• 2008

Lack of honey bee toxicity data for most pesticide products used for strawberry restricts to predict the adverse effects to foraging honey bee after treatment of pesticide in plastic house. This study was conducted to evaluate the actual risk of worker honey bees (Apis mellifera L.) through acute contact toxicity test, acute oral toxicity test and toxicity of residues on foliage test with 21 pesticide products. The mortality of honeybee sprayed with 6 pesticides including dichlofluanid WP showed significantly different from control at recommended application rate in acute contact toxicity test at 24 hours after treatment. Fenpropathrin EC and milbemectin EC treatment groups showed more than 25% mortalities at recommended application rate in acute oral toxicity test. In toxicity of residues on foliage test, only fenpropathrin EC treatment group showed more than 25% mortalities at 10 days after treatment at recommended application rate. It was concluded that the most toxic route to exposure for honey bee is direct contact exposure to sprayed pesticides. Safety interval for honey bee was established by concerning the results of these tests.

• Korean journal of applied entomology
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• v.35 no.2
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• pp.164-172
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• 1996

The comparative toxicity of abamectin to the predatory mite, Amblyseius womersleyi Schicha and the spider mites, Tetranychus urticae Koch and T. kanzawai Kishida was evaluated by leaf disc method. Abamectin was much less toxic to A. womersleyi than to the spider mites. Although survival rate of adult females of A. womersleyi tended to decrease with increasing abamectin concentration, 8-78% of predators remained alive at concentrations of 0.38-6 ppm. Likewise, reproduction was significantly reduced with increasing abamectin concentration. Abamectin neither affect the hatch of A. womersleyi eggs nor the development of surviving immature predators. Survival of immature predators decreased with increasing abamectin concentration. However, 42-90% of immature predators reached adulthood at 0.38-3 ppm. Adult female predators survived on a diet of spider mites intoxicated with abamectin, although their fecundity and the sex-ratio of the progeny were significantly affected. Abamectin at selective sublethal concentrations (0.38-0.75 ppm) could he of value in adjusting predatorlprey ratios in integrated management of T. urticae and T. kanzawai.

• Korean journal of applied entomology
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• v.54 no.4
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• pp.295-301
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• 2015

We investigated mycophagous ladybird, Illeis koebelei from 12 species of plants infected with powdery mildew in Gyeonggi-do, Korea. The pear tree, Pyrus ussuriensis var. macrostipes (Nakai), was most preferred by I. koebelei. This species was found from early July to early November in pear orchards. There was no entomophagous trace in the gut of I. koebelei without powdery mildew spores in a microscope. All stages except egg and pupa are obligate mycophagous, and the feeding potential is ranked as follows: fourth instar, adults, third instar, second instar, and first instar. Feeding amounts of each stage of I. koebelei were 45.6, 144.4, 372.2, 628.1, and $473.7mm^2$ of cucumber powdery mildew per day. Fourth instar larvae showed highest consumption of cucumber powdery mildew. Developmental periods of four larval instars and adults feeding cucumber powdery mildew were 1.2, 2.3, 2.3, 4.6, and 37.7 days, respectively, at $25^{\circ}C$. In this study, we could not determine the feeding potential of I. koebelei against the cucumber powdery mildew; therefore, and further studies are required to elucidate the potential of this species as a biological control agent, e.g., mass rearing, selection of low toxic chemical agents for Integrated Pest Management (IPM), and control techniques against powdery mildew in agro-ecosystems.