• Korean Journal of Environmental Agriculture
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• v.30 no.2
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• pp.173-178
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• 2011

BACKGROUND: Starfish is one of major sea invertebrates that have become a serious economic threat to aquacultural farms in Korea. Much effort has sacrificed to reduce the economic losses of the farms by predatory starfish, including developing and searching biological resources for medicinal and agricultural purposes. In the present study, we investigated aphicidal activity of the extracts from the starfish Asterina pectinifera against green peach aphid. METHODS AND RESULTS: Fresh starfishes were cut into small pieces, homogenized and soaked in methanol. The methanol extracts were centrifuged and the resulting supernatant was subjected to aphicidal activity assays and a series of silica gel column chromatography. More than 70% mortality of aphids were observed by the extracts at a concentration of 1,000 mg/L, exhibiting dose-dependent mortality. TOF-MS analyses detected polyhydroxysteroid as a main aphicidal compound from the starfish extracts. Transmission electronic microscopy could demonstrate that the extracts with polyhydroxysteroid caused aphids death by affecting their epicuticular membrane. CONCLUSION(s): This is the first report of aphicidal activity of the starfish Asterina pectinifera extracts against green peach aphid. Starfish biological resources may be used as a potential candidate for developing a new type natural insecticide.

• Food Science and Preservation
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• v.6 no.3
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• pp.297-302
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• 1999

To investigate an alternative technique to phosphine fumigation, being used for controlling storage insects of dried ginseng, comparative effects of gamma irradiation (5 kGy) and fumigation on the content of moisture, saponins, free sugars, and amino acids of commercially-packaged white ginseng were evaluated immediately after and at the 6th month of storage at 20$^{\circ}C$ and 70% RH after both treatments. The initial moisture content (8.44%) of the sample was not changed with the treatments, and maintained the 10% levels of moisture until 6 months of storage. Major ginsenosides were stable to both treatments, but they showed some reduced content in the control and fumigated samples at the 6th month of storage. Gamma irradiation caused some decrease in the content of free sugars and the subsequent storage of the sample resulted in a further reduction in their content in the order of irradiated, fumigated and control samples. Although irradiation and fumigation brought about a decrease in the content of fee amino acids by about 5%, however the storage period for 6 months was shown more influential than the treatments used for the improvement of biological quality in stored white ginseng.

• Korean journal of applied entomology
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• v.13 no.1 s.18
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• pp.25-31
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• 1974

This survey was aimed to accumulate basic data of aphid population at the Horticultural Experiment Station at Suweon. The yellow pan traps were setted at five locations (Fig.1.), and ran from May 1 to October 31. 1970. About one hundred and twenty species of aphids were trapped, including 24 species of plant vims vectors. Of these, dominant species were as follows: (Asterisk shows virus vector) Aphid species No. of catches * Aphis spiraecola PATCH 2,635, * Aphis craccivora KOCH 2,377, * Myzus persicae SULXER 2,111, Capitophorus hippophaes javanicus H.R. LAMBERS 2,051, Anoecia fulviabdominalis SASAKI 1,480, * Aphis gossypii GLOVER 867, * Macrosiphum avenae FABRICIUS 859, Cervaphis quercus TAKAHASHI 692, * Lipaphis erysimi KALTENBACH 645, Pleotrichophorus chrysanthemi THEOBALD 489, The above 10 species consisted $76.5\%$ of total catches and the 24 vector species consisted $55.5\%$. The curve of the seasonal occurrence of flying aphids at Horticultural Experiment Station shows bimodal, typical for the temperate region. The total number of trapped aphids at the Station from May to September, 1970, were less than that of average yearly catches at the College of Agriculture from 1967 to 1970. Thi, low numbers at Horticultural Experiment Station may attribute to the frequent spraying of insecticides from Spring to Summer on growing crops there. But the aphids population increase suddenly in the middle of October. This might be resulted from cease of insecticide applications and migration of aphids from summer host to winter host plants.

• Korean journal of applied entomology
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• v.53 no.1
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• pp.1-6
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• 2014

The pink citrus rust mite, Aculops pelekassi (Keifer) (Acari: Eriophyoidea), is an important pest in the citrus orchards of Jeju, Korea. This study was performed to investigate the seasonal population abundance of A. pelekassi, and the effects of humidity and citrus leaf age on the multiplication of this pest. Relative humidity (RH) significantly affected the longevity and fecundity of A. pelekassi. Longevity was 7.5, 14.5 and 14.6 d and fecundity was 5.4, 21.5, and 27.1 eggs at 33, 75 and 84% RH, respectively. The leaf age of citrus significantly affected the multiplication of A. pelekassi. The population abundance on 40 day-old leaves was much higher more than 3 times that on 10-day old leaves at 4 weeks after introduction. Overwintered A. pelekassi adults between the bud scales of the citrus trees became active in late April; they were found on newly emerged leaves, followed by their settlement on young fruits in mid-June. The population levels of A. pelekassi peaked on the leaves in late June to July, and on the fruits in early August. The results obtained in this study should be useful for the control of A. pelekassi in citrus orchards in Jeju.

• Journal of Bio-Environment Control
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• v.27 no.3
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• pp.239-244
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• 2018

The effect of the trap equipped with diverse light-emitting lamp on the lure efficiency of whitefly (Trialeurodes vaporariorum) was investigated in the greenhouse cultivating tomato. The light-emitting lamp type equipped to trap was blue, yellow, and white light-emitting lamp. The experiment results showed that trap equipped with blue light-emitting lamp captured the most number of $110{\pm}3.2$ adult whitefly and the number of captured adult whitefly was $71{\pm}1.4$ at yellow light-emitting lamp trap and $45{\pm}1$ at white light-emitting lamp trap respectively. The wavelength distribution band of blue light-emitting lamp was between 330 nm and 430 nm. The wavelength band of yellow and white light-emitting lamp contain repellent wavelength band at the same time. These results show that the trap equipped with blue light-emitting lamp could be used effectively for whitefly control and prevention in the greenhouse cultivating tomato.

• Journal of Life Science
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• v.27 no.9
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• pp.1040-1046
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• 2017

We describe the isolation and characterization of six different intestinal microorganisms from the digestive tract of the cricket Gryllus bimaculatus. Based on 16S rRNA gene sequences, we obtained six isolates belonging to four different genera: Staphylococcus, Bacillus, Citrobacter, and Proteus. All the isolates were resistant to ampicillin. Ampicillin is an irreversible inhibitor of the enzymeetranspeptidase, which is needed to make bacterial cell walls. None of the isolates were resistant to kanamycin, which binds to the 30S subunit of the bacterial ribosome and then inhibits total protein synthesis. Gram staining was conducted, in addition to morphological classification under a microscope. Four grampositive isolates and two gram-negative isolates were detected. The gram-positive isolates were GL1 (round shaped, 2 am in diameter), GL2 (rod shaped, $2.5{\mu}m$ in length), GL3 (rod shaped, $2{\mu}m$ in length), and GL4 (round shaped, $1.5{\mu}m$ in diameter). The gram-negative isolates were GL5 (rod shaped, $2{\mu}m$ in length) and GL6 (rod-shaped, $2.5{\mu}m$ in length). Notably, two of the isolates, GL2 and GL4, secreted specific extracellular proteins. These were determined by MALDI-TOF-MS spectral analysis to be a 87 kDa collagenase, 56 kDa hypothetical protein, and 200 kDa hypothetical protein. The six isolates in this study could be used for various biotechnological applications and pest management, both in the field and in greenhouse systems. In addition, it would be interesting to determine the relationship between these isolates and their host.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.1
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• pp.128-136
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• 2015

This study investigated the effects of low-dose electron beam irradiation treatment on physicochemical and sensorial properties of imported navel oranges during storage at $3^{\circ}C$ for 45 days. The samples were irradiated at doses of 0.2, 0.4, 0.6, 0.8, and 1.0 kGy, and changes in their color values, hardness, Brix/acid ratio, total sugar contents, reducing sugar contents, vitamin C contents, and sensory evaluation were investigated. There were no significant differences between non-irradiated and irradiated samples in terms of color values, Brix/acid ratio, total sugar contents, total reducing sugar contents, and vitamin C contents. Hardness of irradiated sample at 1 kGy decreased significantly in the early storage period, but the difference between non-irradiated and irradiated samples decreased again at the end of storage. For the sensory evaluation, scores of color, sweetness, flavor, and overall acceptability decreased as irradiation dose and storage period increased. Samples irradiated at over 0.8 kGy showed low preference in all scores except color. These results suggest that electron beam irradiation below 0.6 kGy does not affect physicochemical and sensory properties; thus, electron beam irradiation up to 0.6 kGy in imported navel oranges is optimum for minimizing quality changes and disinfestation treatment simultaneously.

• Korean journal of applied entomology
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• v.60 no.4
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• pp.369-377
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• 2021

Mass trapping of the western flower thrips, Frankliniella occidentalis, has been considered as an option to control this pest. This study applied the commercial lures to the hot pepper-cultivating greenhouses and assessed the enhancement of the attracting efficiency by adding to sticky traps. There was no color difference in the attracting efficiency between blue and yellow sticky traps. However, the installation position of the traps was crucial in the greenhouses. The more thrips were captured within host cropping area than outside areas of the crop. In vertical trap position, it was the most optimal to install the traps at the crop crown. Using these installation parameters, the yellow sticky traps captured approximately 1% population of the thrips. To enhance the trapping efficiency, the commercial lures containing aggregation pheromone or 4-methoxybenzaldehyde were added to the yellow sticky traps. However, these commercial lures did not significantly enhance the trapping efficiency compared to the yellow sticky trap alone. In contrast, Y-tube olfactometry assays confirmed the high efficiency of the aggregation pheromone or another plant volatile (methyl isonicotinate) to attract the thrips. Interestingly, these lure components had lower attracting efficiencies compared to the hot pepper flowers. The high attractive efficiency of the flowers was supported by the observation that the commercial lure was effective to enhance the trapping efficiency of the yellow sticky trap against F. occidentalis in Welsh onion (Allium fistulosum) field without any flowers. This study indicates the limitation of the commercial lures in application to hot pepper fields for the mass trapping of F. occidentalis. It also suggests active volatile component(s) from hot pepper flowers to attract F. occidentalis.

• Journal of Life Science
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• v.29 no.2
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• pp.202-208
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• 2019

Brown planthopper (BPH), Nilaparvata lugens Stål (Hemiptera: Delphacidae), is one of the most important migratory pests damaging rice in Korea. It invades annually from tropical and subtropical areas via continental air streams. It is necessary to determine the resistance levels of rice varieties in order to control efficiency. The honeydew excretion, development, and reproduction of the migratory BPH were studied by region in a laboratory at $25{\pm}2^{\circ}C$ and $65{\pm}5%\;RH$ and a 16L: 8D photoperiodism conducted on three BPH resistant genes: Bph1, Bph2, and Bph18. The information obtained was reported using the jackknife method, and we created life table statistics accordingly. The feeding amount of Bph1 resistant gene was lower than that of resistant genes. The developmental periods of immature stages ranged from $13.7{\pm}0.10d$ on Bph2 (Namhae, 2015) to $18.5{\pm}1.06d$ on Bph2 (Sacheon, 2016). Reproductive period and female longevity were longest on the non-resistant genes, Bph2 and Bph18 (except 1980s), and the highest fecundity of N. lugens was observed on the two BPH resistant genes. Highest net reproductive rates ($R_0$) were calculated on Bph2 by region. Intrinsic rates of population increase ($r_m$) showed a difference in resistant genes by region. These population parameters showed that migratory regions and biological characteristics of N. lugens vary annually.

• Journal of Practical Agriculture & Fisheries Research
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• v.22 no.2
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• pp.135-146
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• 2020

In the strawberry cultivation areas and domestic farms, two-spotted spider mites are the most serious pests. It decreases the product yield due to the direct feeding of chlorophyll by the mites resulting in reduced photosynthetic ability of host plant. In this study, a simplified acaricidal effect evaluation system (SAEES) was employed to choose the effective acaricidal products among 10 items based on leaf-dipping bioassay methods. SAEES had the advantage of being able to screen four commercial products with three replications at the same time in the recommended concentration. The susceptible strains (SL_YS) showed a high mortality rate of about 90-100%, whereas the mortality of local strains was differed by each acaricides. It suggests that the acaricide responses of field populations might differ due to spray frequencies and acaricide product. An efficacy index (0.8-1.0) was determined based on the mortality of susceptible strain, which would allow the most effective commercial products to be selected by the range of this index. In summary, SAEES will enable the selection of effective commercial products and contribute to increasing control against T. urticae in strawberries.