• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.387-390
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• 2012

Beet armyworm (Spodoptera exigua), diamondback moth (Plutella xylostella) and tobacco cutworm (S. litura) are insect pests causing damage in many economically important vegetables in Korea. Bacillus thuringiensis, commonly known as Bt, has been available as an alternative insecticide for many years. Five commercial Bt products and the mixtures evaluate the control efficacy against three kinds of moths. These commercial Bt products had high control efficacy against $2^{nd}$ instar of diamondback moth, but didn't show high mortality against beet armyworm and tobacco cutworm. Mixtures of Bt products didn't have synergistic effects to the tested moths. Also application of twice and four times the recommended concentration didn't improve the control effects against the tested three species of moths.

• Korean Journal of Environmental Agriculture
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• v.39 no.2
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• pp.83-88
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• 2020

BACKGROUND: This study was carried out to investigate residual characteristics of diethofencarb during ginseng cultivation and processing, and to establish the maximum residue limits (MRL) of ginseng and its processed products. METHODS AND RESULTS: Supervised field trials were conducted from three fields located at Seosan, Goesan and Jeongeup in Korea. Diethofencarb 25% WP was diluted by 500 times and sprayed 4 times onto the ginseng with 10 days interval. The samples were collected at 80 days after final application. The residual amounts of diethofencarb ranged from 0.074 to 0.460 mg/kg in fresh ginseng, from 0.292 to 0.720 mg/kg in dried ginseng, and from 0.208 to 0.557 mg/kg in red ginseng. These data exceeded the ginseng's MRL, 0.3 mg/kg. The processing factors of diethofencarb in processed products were found to be 2.64 and 1.99, respectively for dried and red ginseng. CONCLUSION: Given the lower residual concentration of red ginseng that goes through a more complicated process than dried ginseng, the residual concentrations of diethofencarb in processed ginseng products were found to be dependent on processing method. Therefore, it is necessary to reconsider the MRL of diethofencarb in fresh ginseng and its processed products.

• Journal of Applied Biological Chemistry
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• v.62 no.1
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• pp.11-17
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• 2019

Strawberries are one of the main commodities in Korea and have been exported over 40 million dollar. Because the strawberry cultivation using hydroponics has increased, treatment of pesticide by drenching draw interest recently. However, detailed researches for drenching treatment of pesticide are limited, which results in difficulties in proper pesticide applications in agricultural fields. To activate use of drenching and improve safety in agricultural products, In this study, time-dependent residual characteristic of pesticides were compared with between different applications of pesticides in strawberries. The characteristics of azoxystrobin, prochloraz and thiamethoxam were investigated with drenching treatment at different applications: the time of treatment, concentration etc. at hydroponic cultivation for 40 days. Azoxystrobin and prochloraz were not detected at 14 day after application. Thiamethoxam was detected from 0.02 to 0.85 mg/kg. Crop uptake of pesticides was strongly affected with octanol-water partition coefficient and solubility in water. Residual amount in crops are highly dependent on the concentration of active ingredient of pesticides.

• Journal of Food Hygiene and Safety
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• v.32 no.1
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• pp.20-26
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• 2017

Foodborne disease outbreaks associated with produces have been increasing in occurrence worldwide. This study investigated microbial contamination levels on thirteen kinds of agricultural products from farms stage to evaluate potential hazards associated with foodborne illness. A total of 1,820 samples were collected in major cultivating area from 2013 through 2015, and analyzed to enumerate aerobic bacterial counts, coliforms/E. coli, Bacillus cereus and Staphylococcus aureus. In addition, the prevalence study for four kinds of microorganisms (Escherichia coli, E. coli O157:H7, Salmonella spp. and Listeria monocytogenes) was performed on each sample. Aerobic bacterial counts ranged from 0.01 to 7.18 log CFU/g, with the highest bacterial cell counts recorded for watermelon. Coliforms were detected in 651 samples (35.8%) with a minimum of 0.01 log CFU/g and a maximum of more than 5 log CFU/g. B. cereus was detected in 169 samples (9.3%) ranging from < 0.01 to 2.48 log CFU/g among total samples analyzed. S. aureus was detected in 14 samples (0.7%) with a minimum of 0.01 log CFU/g and a maximum of 1.69 log CFU/g. E. coli was detected in 101 samples (5.5%) among 1,820 samples. E. coli O157:H7, Salmonella spp. and L. monocytogenes were not detected in any of the samples. The microbial contamination levels of several agricultural products determined in this study may be used as the fundamental data for microbiological risk assessment (MRA).

• Journal of Applied Biological Chemistry
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• v.60 no.4
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• pp.313-319
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• 2017

Strawberries are one of the main commodities in Korea and have been exported over 30 million dollar. And the safety has recently become an important issue in the agro-trade, pesticide residue is most important matter of safe agricultural products. As strawberries can be cultivated using elevated production system, so it is possible to use the drenching. When spraying the pesticides, the use of drenching can be lower amount of residual than using foliar treatment. In this study, time sequential residual amount of pesticides were compared between drenching and foliar application in strawberries. Pesticides were treated with the standard and double dosage and samples were collected at 0, 3, 6, 9, 13, 16 and 21 day and analyzed by LC and LC-MS/MS after liquid-liquid extraction and QuEChERS. Two pesticides were detected less than 1 mg/kg in all samples for drenching treatment. Carbendazim residues in drenching treatment were 5 to 25 times lower than foliar application. And azoxystrobin was not detected in strawberries of drenching treatment.

• Journal of Microbiology and Biotechnology
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• v.26 no.12
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• pp.2138-2140
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• 2016

The goal of this study was to identify a source of natural plant compounds with inhibitory activity against pepper mild mottle virus (PMMoV). We showed, using a half-leaf assay, that murrayafoline-A (1) and isomahanine (2) isolated from the aerial parts of Glycosmis stenocarpa have inhibitory activity against PMMoV through curative, inactivation, and protection effects. Using a leaf-disk assay, we confirmed that 2 inhibited virus replication in Nicotiana benthamiana. Using electron microscopy, we found that a mixture of the virus with 2 resulted in damage to the rod-shaped virus.

• Journal of Plant Biotechnology
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• v.1 no.1
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• pp.61-68
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• 1999

Rapid accumulation of reactive oxygen species (ROS) and their toxic reaction products with lipids and proteins significantly contributes to the damage of crop plants under biotic and abiotic stresses. We have identified several stress activated alfalfa genes, including the gene of the alfalfa ferritin and a novel NADPH-dependent aldose/aldehyde reductase enzyme. Transgenic tobacco plants that synthesize alfalfa ferritin in vegetative tissues-either in its processed form in chloroplast or in the cytoplasmic non-processed form-retained photosynthetic function upon free radical toxicity generated by paraquat treatment and exhibited tolerance to necrotic damage caused by viral and fungal infections. We propose that by sequestering intracellular iron involved in generation of the very reactive hydroxyl radicals through a Fenton reaction, ferritin protects plant cells from oxidative damage. Our preliminary results with the other stress-inducable alfalfa gene (a NADPH-dependent aldo-keto reductase) indicate, that the encoded enzyme may play role in the stress response of the plant cells. These studies reveal new pathways in plants that can contribute to the increased stress resistance with a potential use in crop improvement.

• International Journal of Industrial Entomology and Biomaterials
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• v.40 no.2
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• pp.41-50
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• 2020

Vermicompost, manure, compost and organic fertilization are ecofriendly. Nowadays, many products resulted from sericulture consumed by humans such as mulberry leaves, fruits, mulberry tea, silk and natural silk cosmetics. Soil applications of three treatments with vermicompost (0.5, 1 and 2 tons per 0.42 hectare) and recommended rate of mineral fertilizers of nitrogen phosphorus potassium were used for investigation. Impact of fertilization on mulberry plant traits of moisture, number of shoots/tree, total shoots length/tree, number of leaves/shoot, number of leaves/ (100g), leaf yield/tree and leaf yield of fadden/season were recorded. In addition the effect of fertilization on larval and cocoon characters of young instar duration, fifth instar duration, total larval duration, larval mortality percentage, weight of third instar larvae, weight of fourth instar larvae, weight of fifth instar larvae, fresh cocoon weight, fresh shell weight, pupae weight, cocoon shell ratio, silk productivity, cocooning percentage, pupation ratio, number of cocoons/ liter, crop cocoons by number, crop cocoons by weight, fecundity and fertility. Using vermicompost treatment was enhancing plant characters. Treatments of V₃, V₂ and V₁ were shortage young, fifth and larvae durations. Mostly feeding silkworm during the whole larval duration on treated mulberry leaves with vermicompost improving the traits average. Using vermicompost for fertilization by rate of V₃ and V₂ is better than others for cocoon characters for females and males.V₃ and V₂ of vermicompost per 0.42 hectare is recommended for rearing mulberry silkworm instead of mineral fertilization.

• Proceedings of the Korean Society of Crop Science Conference
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• 2001.09a
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• pp.34-58
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• 2001

Within the paper, an overview of organic farming in Europe countries is given and the Principle and skills of organic agriculture is shortly reported with special regard to Germany. The overview information on European organic farming is covered such as (1)development of organic farming, (2) organic farming organizations, (3)standards and certification, (4)implementation of EU council regulation, (5)state support, (6)implementation of Agenda 2000, (7)training and education, (8)advisory service and research situation. In the paper the principle and skills for organic farming which are practiced actually in the German organic farms is also reported. How to maintain and increase the fertility and microbiological activity of the soil by (1)cultivation of legumes, green manures or deep-rooting crops in multi-annual rotation system, (2)incorporation in the soil organic material, by-products from livestock farming is one of the major principle to organic crop production. Pest and diseases and weeds are controlled by any one, or a combination of the following measure; (1) choice of appropriate species and varieties, (2)appropriate rotation programs, (3)mechanical cultivation, (4)protection of natural enemies of pests through provision of favourable habitat and ecological buffer zone, (5)diversified ecosystems, (6)flame weeding, (7)natural enemies, (8)bio-dynamic preparations, (9)mulching and mowing, (10)grazing of animals, (11)mechanical controls, (12)steam sterilization.

• Korean Journal of Medicinal Crop Science
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• v.21 no.5
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• pp.353-360
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• 2013

Korean ginseng (P. ginseng C. A. Meyer) is one of the most important medicinal plant in the world. Understanding genetic variability among the assortment of Korean ginseng is important for breeding. The aim of this study was to molecularly characterize Korean ginseng cultivar and breeding lines through the use of eight previously reported STS markers (MFGp183, MFGp130, MFGp110, UFGp74, UFGp163, MFGp108, MFGp81 and UFGp156). All STS markers produced interpretable electropherograms from 31 accessions consisting of 11 Korean ginseng cultivars and 20 breeding lines. When eight STS markers were combined, we identified to total 19 genetic patterns; in particular, nine cultivars (Chunpoong, Yunpoong, Gopoong, Gumpoong, Sunpoong, Sunone, Cheongseon, Sunhyang, Cheonryang) and 5 breeding lines (G08012, G04079, G04075, G08036, G04110) in ginseng samples can be discriminated from the others. Together with other available markers, these STS markers will contribute to the management of ginseng genetic resources and the protection of breeders' rights.