• The Korean Journal of Pesticide Science
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• v.2 no.3
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• pp.126-136
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• 1998

For the purpose of effective control strategy of the melon aphid, Aphis gossypii and the diamondback moth, Plutella xylostella, thiamethoxam and 3 other insecticides in different classes were used with bioassay test methods in laboratory and greenhouse. They were examined to evaluated and compared with contact toxicity, stomach toxicity, rapid action, systemic action, and residual effect of imidacloprid, thiamethoxam (nicotinoids), acephate (organophosphorates), and carbosulfan (carbamates). As results of contact toxicity responses of A. gassypii against 4 insecticides using a spray application method, $LC_{50}$ values of acephate, carbosulfan, imidacloprid and thiamethoxam were 41.9, 5.2, 1.1, and 0.7 ppm. respectively. In the evaluation of stomach toxicity response of P. xylostella using a leaf-dipping method, with the 2nd instar larva $LC_{50}$ values of imidacloprid, thiamethoxam and acetamiprid were 64.9, 24.6 and 15.2 ppm, with the 3rd instar larva were 125.2, 42.7 and 27.8 ppm. and with the 4th instar larva were 241.1, 44.5 and 23.9 ppm, respectively. In the case of rapid action to A. gossypii using a spray application method after inoculation, $LT_{50}$ values of imidacloprid, thiamethoxam, carbosulfan, and acephate were 26.6, 28.0, 30.3, and 41.7 min. respectively. Otherwise, in the inoculation after applying compounds, $LT_{50}$ values of thiamethoxam, imidacloprid, and carbosulfan were 95.5, 118.0, and 122.9 min. respectively. Evaluating to systemic action from the abaxial surface to the adaxial surface of red pepper leaf with spray method, $LT_{50}$ values of thiamethoxam, imidacloprid, and carbosulfan were 162.2, 168.9, and 564.1 min. respectively. For the systemic action from the lower leaves to the upper leaves on red pepper, $LT_{50}$ values of carbosulfan, thiamethoxam, imidacloprid, and acephate were 2.3, 2.9, 3.0, and 8.8 days, respectively. In red pepper plant, $LT_{50}$ values of carbosulfan, imidacloprid, thiamethoxam, and acephate on the systemic action from the roots to the upper leaf were 0.6, 1.0, 1.0, and 13.8 days, respectively. As these results, it might be that thiamethoxam was excellent on systemic effect in red pepper. For the evaluation of residual effect on red pepper with A. gossypii, thiamethoxam and imidacloprid maintained high control effects as over 80% upto 10 days after treating compounds.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.659-666
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• 2010

Lysobacter antibioticus HS124 was isolated from rhizosphere soil in previous experiments, which produced lytic enzymes such as chitinase, gelatinase, lipase and protease. In addition, HS124 released an antibiotic compound, 4-hydroxyphenylacetic acid (4-HPAA). When larvae of P. xylostella was treated with HS124 culture broth, its body was destroyed, and degraded with the increase of incubation time, yielding glycine which was detected from HS124 culture broth. When 4-HPAA produced from HS124 was sprayed, larvae mortality increased with increasing concentration of 4-HPAA. When HS124 culture supplemented with Tween 80 was sprayed, its insecticidal activity against larvae was approximately 1.4 times higher compared to the culture without Tween 80. Insecticide (IS), HS124 culture broth (HS124), Magic-pi (MP) and HS124 culture broth+Magic-pi (HS124+MP) were each treated against larvae of P. xylostella to investigate their insecticidal effect where sterile diluted water (SDW) was used as a control. The highest mortality of larvae was found in HS124+MP, followed by IS, MP, HS124 and SDW respectively. Mortality of larvae in HS124 was 31% higher than that in SDW, but 41% lower than that in HS124+MP, meaning that both enzymes and antibiotics produced from HS124 may synergistically act as active agents with plant extract containing neem oil and turmeric in HS124+MP treatment. These results suggested that L. antibioticus HS124 together with plant extract can be one of candidates for biocontrol agents against Plutella xylostella.

• The Korean Journal of Pesticide Science
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• v.7 no.1
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• pp.38-44
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• 2003

In vitro inhibitory activity of 34 insecticides and 31 fungicides to glutathione-S-transferase and esterases extracted from rats was determined. Of tested pesticides, the pesticides with high activity on both detoxifying enzymes were mixed with pesticides that are known to be detoxified by detoxifying enzymes. Glutathione-S-transferase was inhibited by thiodicarb $(I_{50}:1.87\times10^{-4}M)$, thiocyclam $(7.40\times10^{-4}M)$, dithianon $(7.55\times10^{-5}M)$, and tolylfluanide $(8.66\times10^{-5}M)$, while esterases by dichlorvos $(8.95\times10^{-8}M)$, pirimicarb $(2.74\times10^{-6}M)$, pyrazophos $(3.31\times10^{-5}M)$, and benomyl $(4.96\times10^{-5}M)$. After acephate known to be detoxified by glutathione-S-transferase was mixed with glutathione-S-transferase-inhibiting pesticides and phenthoate known to be detoxified by esterases was mixed with esterases-inhibiting pesticides, insecticidal activities of such mixtures were determined against diamondback moth (PlutelLa xylostella L.). Synergistic action was observed in all pesticide combinations. The highest synergistic action was obtained when phenthoate was combined with dichlorvos, showing that co-toxicity coefficients were 1512 and 1877 after 24 and 48 hours of treatment, respectively. Several other combinations of pesticides, such as phenthoate with benomyl, and acephate with dithianon, also showed synergism, showing that their co-toxicity coefficients were about 1,000 and 500, after 24 hours of treatment, respectively. Our results showed that combinations of pesticides inhibited by detoxifying enzymes and ones detoxified by detoxifying enzymes resulted in increased toxicities of pesticides, suggesting that such combinations could be used to develop pesticide mixtures with more broad spectrum and high effectiveness.

• Korean journal of applied entomology
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• v.53 no.2
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• pp.157-169
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• 2014

Between 2010 and 2012, diseases and insect pests of sweet persimmon were surveyed at sweet persimmon export complexes and non-export orchards in Suncheon, Jeonnam Province; Jinju, Changwon (Dongeup and Bukmyeon), and Gimhae, Gyeongnam Province; and Ulzu, Ulsan. The following diseases were found in the sweet persimmon orchards: angular leaf spot (Cercospora kaki), anthracnose (Colletotrichum gloeosporioides and Colletotrichum acutatum), circular leaf spot (Mycosphaerella nawae), powdery mildew (Phyllactinia kakicola), and gray mold (Botrytis cinerea). Circular leaf spot was the most frequent and serious disease, and C. gloeosporioides and C. acutatum were found on fruits. Thirty-three insect pest species that belonged to 32 genera of 20 families in 5 orders were found in the sweet persimmon orchards; the two-spotted spider mite, Tetranychus urticae, was also found in the surveyed orchards. Apolygus spinolae, Pseudaulacaspis cockerelli, and Adoxophyes orana were widely found in the surveyed orchards; Spodoptera litura and Homona magnanima were also recorded. Damage by insect pests was low, and the quarantine insect pests peach pyralid moth (Dichocrocis punctiferalis) and persimmon fruit moth (Stathmopoda masinissa) were rarely or not found in the sweet persimmon export complexes. In addition, other quarantine insect pests, such as persimmon false spider mite (Tenuipalpus zhizhilashviliae) and Japanese mealybug (Planococcus kraunhiae), were not detected. These quarantine insect pests were also not found in the sorting places, storage houses, and fruits for export; however, scale insects and two-spotted spider mites were found at a low rate. Although anthracnose (C. acutatum) infested fruit was found in the storage houses, only one in Jinju and Gimhae.

• Korean journal of applied entomology
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• v.57 no.3
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• pp.209-220
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• 2018

Mating disruption (MD) has been widely used to effectively control Grapholita molesta in apple orchards. A simultaneous mating disruption (SMD) techniques have been developed to control both G. molesta and G. dimorpha. This study was performed to determine the practical parameters to apply the SMD technique to field conditions. To determine the application amount of SMD lures, a dispenser containing 10 mg pheromone was placed at different numbers of trees in an orchard. Application at every other tree (= one dispenser per two trees) was relatively safe to expect effective MD efficiency in both wax and polyethylene (PE) formulations. One time application at the end of March was enough to maintain a year round MD efficacy against both species. A fence treatment using food trap was applied to prevent any immigratory mated females from nearby untreated regions. To enhance the food trap by adding host-derived secondary compounds, terpinyl acetate (TA) was screened to be effective to attract females of Grapholita molesta among six compounds contained in apple fruit extracts. Among different TA concentrations, 0.05% TA treatment was the most effective to attract the adults. A mixture of TA and sugar was effective to attract and kill females and called FAKT (female attract-to-kill techniques). FAKT was treated at approximately 6 m interval at the edge of the apple orchards. The females trapped by the FAKT included mated females possessing vitellogenic oocytes. SMD supplemented with FAKT maintained the high MD efficacy and significantly suppressed leaf damage induced by the two insect pests compared to control or single SMD treatment.

• Korean journal of applied entomology
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• v.53 no.4
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• pp.355-365
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• 2014

It has been unclear whether the diamondback moth, Plutella xylostella can overwinter in Korean field conditions. This study determined overwintering conditions of P. xylostella by conducting field exposure tests based on its cold tolerance and monitoring overwintering populations by direct examination of overwintering larval habitats and capturing adults with sex pheromone traps. In addition, the overwintering populations were analyzed using polymorphic genetic markers to trace their sources. When all immature stages of P. xylostella were exposed to $-5^{\circ}C$, which was the temperature much above their supercooling points, they significantly suffered with direct cold injuries, where larval stage was most tolerant to the cold injury. However, the exposure to $5^{\circ}C$ for a long period (4 weeks) did not give any significant cold injury to nonfeeding stages, while this treatment gave lethality to larval stage without diet. When all developmental stages of P. xylostella were exposed to open field conditions during winter, they exhibited significant decreases of survival rates. However, some protected and indoor conditions reduced the cold injuries and the diet provision significantly increased larval survival rates. Adult monitoring with sex pheromone during winter period indicated that the first captures were observed at similar periods at different locations (${\approx}260$ Km apart). The overwintering adults were captured until early April. Genetic variation of these overwintering populations was analyzed with polymorphic molecular markers, indicating significant genetic divergences among the overwintering populations. This study indicates that P. xylostella can overwinter in southern Korean fields or some protected greenhouses with host plants.

• Korean Journal of Environmental Biology
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• v.36 no.2
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• pp.206-216
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• 2018

We analyzed the effects of spatio-temporal variation in the leaf production of oaks on the density and species richness of herbivores, as well as the consumption by herbivores in the east coastal region of Korea, which is an area that has been damaged by forest fires. The main herbivore that feeds on oak leaves was moth larvae. In mid-August the insect larvae showed the highest density and species richness. Approximately 60.5% of total plant-eating insect larvae were present from August to September 2011. Oak leaf production was at its peak from July to August, and the peak damage caused by herbivores was from August to September. Depending on the investigation timing and site of the survey, oak leaf production, larval densities, and species richness showed large variations. The average production of oak leaves between July and August was estimated to be $0.96ton\;ha^{-1}$. The production of oak leaves during this period also showed spatial variations ranging from 0.34 to $1.89ton\;ha^{-1}$. In August, the consumption of oak leaves by the herbivores showed spatial variations ranging from 0.15 to $1.51ton\;ha^{-1}$. Where oak leaves had a higher yield, they tended to increase in density and species richness of the herbivores. As the production of oak leaves increased, so did the overall consumption and consumption rate by the herbivores. This means that the production of oak leaves is highly related to time and space, and there is a concentration response in which the new individuals gather. Research into the spatio-temporal heterogeneity of the food sources and their effects on the higher levels of the food web can help us quantitatively understand and evaluate the structure and functions of the burnt ecosystem that is caused by forest fires.

• Korean journal of applied entomology
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• v.45 no.2 s.143
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• pp.201-209
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• 2006

Five strains of Korean entomopathogenic nematodes (EPN), steinernematids and heterorhabditids were evaluated and tried in laboratory, pot, and vegetable greenhouses for environmentally friendly control of diamondback moth (DBM), Plutella xyiostella, from 2002 to 2005. LC$_{50}$ values of five EPN strains against DBM were different depending on nematode strain and DBM instar. LC$_{50}$ value of Steinernema carpocapsae GSN1 (GSN1) was the lowest representing 2.6$\sim$3.9 infective juveniles (Ijs, 3rd stage) to 2nd to 4th instars of DBM. Pathogenicity of five effective strains against DBM was different depending on nematode strain, concentration, application times, and vegetable in pot. The most effective nematode was GSN1. Steinernema spp. was more effective than Heterorhabditis spp. against DBM. Two or three times of applications of EPN were effective regardless of nematode strain and concentration in pot. Efficacy of EPN was different depending on vegetable species. Efficacy was higher on Chinese cabbage, red mustard, and Ssamchoo than that on cabbage, kale, and leaf broccoli. Efficacy of GSN1, Steinernema GSNUS-10, Steinernema CSNUS-14, and Heterorhabditis GSNUH-1 was variable depending on nematode strain, concentration, application times, and vegetable in greenhouse experiments. GSN1 was the most effective and 100,000 infective juveniles per m$^2$(=$1\times10^9$ Ijs/ha) resulted in higher efficacy. Three times of application of nematodes led to higher control efficacy than one or two applications. Efficacy of nematodes was higher on Chinese cabbage than cabbage or kale in greenhouse.

• Korean journal of applied entomology
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• v.24 no.4 s.65
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• pp.183-190
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• 1986

Identification of fruit sucking moths, their larval host plant, and degree of damages to fruits were investigated in $1982{\sim}'83$ at two orchards in Cheonnam province. In this study, 4 families 30 species were collected as fruit sucking moths and among them 10 species are newly recorded in Korea as fruit sucking moth: Catocala electa(B.), Spirama helicina(H.), Erebus ephesperis(H.), Parallelia stuposa(F.), Simplicia niphona(B.), Marumba gaschkewitschii(B. et G.), Agrius convolvuli(L.), Thyatira batis (L.), and Spilosoma niveum(M.). Larval host plants of fruit sucking moths in the vicinity of the fruit orchard include Cocculus trilobus D., Albizzia julibrissin D., Pterocarya rhoifolia S., Jaglans mandshurica M., Solanum melongena L., Brassia campestris S., Rubus idaeus C., Thalictrum aquilegifol L., and Rhus succedanea L. As the damage on different varieties of the main fruit trees, plum was orderly Santa Rosa>Beauty, Apple was Chook>Hong Og, Peach was Choseng Baeg Do>Hwang Do>Baeg Do, and Grape was Campbell Early>Neo Mascat>Golden Queen. Seasonal occurrence of main fruit sucking moth Spirama retorta(C.) showed peak 3 times in early-July, late-July, early-September. Oraesia emerginata(F.) showed peak 3 times in late-July, early-August, early- September and Lagoptera juno(D.) showed peak only in late-July and Adrias tyrannus amurensis(S.) showed peak only in mid-July. Fruit sucking moths were immigrated from p.m. 6 to a.m. 2, with peak in p.m. 10 to p.m. 12.

• The Korean Journal of Zoology
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• v.16 no.1
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• pp.25-41
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• 1973

Ultrastructural changes in the cells of the corpora allata of the pine moth, Dendrolimus spectabilis Butler, were studied by electron microscope to know the structural correlates of hormone production by the gland during the larval-pupal-adult transformations. Mitochondria are in active phases from the overwintered to the last instar larvae and from the pupae just after pupation to the 20-day old pupae, while they are in inactive phases from the making cocoon stage to the prepupae just before pupation. The peripheral allatum cells have electron dense granules in the intracellular vacuoles of smooth-surfaced endoplasmic reticulum in the larval life, particularly in the overwintered larvae and in the early adults but the swollen smooth-surfaced intracytoplasmic vacuoles made by expansion of an end of the tubular rough endoplasmic reticulum, some of which contain fibrous proteins, are observed in addition to the vacuoles in the intercellular spaces in which the vacuoles grow by fusing each other from the mature larvae to the prepupae, both of them disappearing during just before pupation. After pupation the cytolasmic vacuoles develop again in the allatum cells so that they seem to begin the secretory activity. The fact that the neurosecretory granules stored within the axons terminated in the corpus allatum are visible only from the 20-day old pupa about two days before abult emergence to the 5-day old adult means that the secretion from the allatum cells is under the control of the brain from the late pupal stage, while the secretion during from the larval to the early pupal life has no relation with the brain, because such granules are not observed within the axons. It is, therefore, suggested that at least two kinds of hormone are released with the ages as far as concerned with the production and secretion mechanisms of the allatum hormone: juvenile hormone is released until the last instar larvae without any direct stimlation of the brain and gonadotropic hormone is secreted from the late pupa to the adult by getting brain's stimulation and that the secretory phases observed from the mature larvae to prepupae are presumably concerned with the biosynthesis of protein owing to the ecdysone and those from the early pupal stage in uncontrolled condition of the brain with the prothoracotropic activity.