• Proceedings of the Korean Society for Agricultural Machinery Conference
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• v.10 no.1
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• pp.37-41
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• 2005

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2000.06a
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• pp.49-49
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• 2000

• Analytical Science and Technology
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• v.9 no.2
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• pp.123-133
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• 1996

The optimum conditions for the analysis of the difenoconazole fungicide on soil and crops were investigated and the residues of that in apple and soil were identified by using the gas chromatography. The extract with acetonitrile was separated with saturated NaCl and n-hexane solution after filtered, and concentrated. Obtained fungicide residues were transfered to the florisil column and eluted with acetone and n-hexane mixed solution for the analysis by GLC(ECD). From the standard addition experiments with 0.20 and 1.0ppm, the average recoveries were 86~92% and the detection limit was 0.01 ppm. It seems to be safely used when difenoconazole is treated three times until 15 days before harvest of apple. In this case residual amounts of difenoconazole in apple was from 0.037ppm to 0.044ppm. The soil samples extracted with methanol and ammonium hydroxide mixed solution were partitioned with dichloromethane and saturated sodium chloride solution. The organic phase was concentrated and redissolved with toluene and analyzed with GLC(FID) after cleaned with Sep-Pak column. From the standard addition experiments with 0.10, 0.50 and 1.0ppm, the average recoveries were 101.2~103.7% and the detection limit was 0.025ppm.

• Journal of the Korea Organic Resources Recycling Association
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• v.7 no.2
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• pp.73-82
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• 1999

To verify the usefulness of enzyme activity as a index for the stability or maturity of apple pomace composting. the succession of microbial populations using viable count procedure. and Vmax of ${\beta}$-glucosidase and cellobiohydrolase were measured. based on an increase in fluorescence as the nonfluorescent methylumbelliferyl substrates were enzymatically hydrolyzed, leading to the highly fluorescent methylumbelliferyl molecule 4-methylumbelliferone(MUF). The activities of these enzymes in the decomposition of carbohydrates were gradually decreased in the course of the time. Correlation between microbial population and enzyme activity was not significant with exception of fungi. and the fungi were represented in high density. This indicates that the fungi probably play a major role in composting of apple pomace.

• Korean Journal Plant Pathology
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• v.12 no.2
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• pp.219-255
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• 1996

사과 겹무늬썩음병의 주 전염원은 가지 병반에서 형성되는 자낭포자 및 병포자이므로, 가지에서의 포자형성 또는 포자의 분산을 화학적 또는 물리적 방법으로 저해할 수만 있다면 효과적으로 병을 방제할 수 있을 것으로 생각했다. 전염원을 줄이기 위한 첫 번째 시도로 1992년 이른봄 가지에 형성된 사마귀를 호미로 제거한 결과, 병포자의 분산과 과실발병 억제효과에 있어서 무처리와 유의적인 차이가 인정되지 않았다. 두 번째 시도로 포자의 분산을 막기 위해 1993년 이른봄에 겹무늬썩음병에 걸린 가지를 비닐필름으로 감고 5월부터 9월까지 20일 간격으로 살균제를 살포한 결과, 통계적으로 유의성이 인정되는 병 방제효과가 있었고, 나무의 생육에 있어서도 콜크층이 이상 비대하는 것 이외에 별다른 이상이 없었다. 이 개념을 더욱 발전시켜 1994년 이른봄에는 병든 가지를 수용성 고분자 물질인 polyvinyl alcohol로 도포하고 수배 분산 포자의 수를 조사한 결과, 포자의 분산량이 크게 줄어져 실용화의 가능성이 시사되었다.

• Journal of Plant Biotechnology
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• v.46 no.3
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• pp.228-235
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• 2019

Apple (Malus pumila) is one of the most economically important fruits in Korea. but virus infection has decreased the sustainable production of apples and caused serious problems such as yield loss and poor fruit quality. Virus or viroid infection including apple chlorotic leaf spot virus (ACLSV), apple stem pitting virus (ASPV), apple stem grooving virus (ASGV), apple mosaic virus (ApMV) and apple scar skin viroid (ASSVd) have been also reported in Korea. In many cases, as apple gets infected with virus and viroid with no specific symptoms, the damage and symptoms caused by the viruses are not detected. In our research, viruses in the rootstock were eliminated for a virus-free apple dwarfing rootstock of M.9 and M.26. The virus elimination methods were apical meristem culture, thermotherapy ($37^{\circ}C$, 6 weeks) and chemotherapy($Ribavirin^{(R)}$). The detection of apple viruses was accomplished by Enzyme-linked Immuno-Sorbent Assay (ELlSA) and reverse transcription-polymerase chain reaction (RT-PCR). RT- PCR method was 10 ~ 30% more sensitive than the ELISA method. The efficiency of virus elimination was enhanced in apical meristem culture method. The acquisition rate of virus-free apple dwarfing rootstocks was 30 ~ 40% higher in apical meristem culture. After the meristem culturing of M.9, the infection ratio of ACLSV, ASPV and ASGV was 45%, 60% and 50%, respectively. In the apple dwarfing rootstock of M.26, the infection ratio of ACLSV, ASPV and ASGV was 40%, 55% and 55%, respectively. Based on this study, the best method for the production of virus-free apple dwarfing rootstocks was the apical meristem culture.

• Korean journal of applied entomology
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• v.32 no.3
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• pp.259-264
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• 1993

The experiment was carried out to investigate Insecticide susceptibility of the spiraea aphid (Aphis citricola) in apple orchards In Korea, using dipping method. Although insecticIde susceptibility vaned with local and seasonal populations, the susceptibility to demeLon S-rnethyl and phosphamidons was different from that Lo the other insecticides. The LCso values were 10 ppm for deltamethrin and chloropyrifos, 103 ~ 629 ppm for demeton S-methy1, acephate, phosphamidon, monocrotophos and vamldothion, 12,200 ppm for EPN, and 1,745 ppm for pirimicarb. 'When Insecticide susceptibility was compared between the S-clone selected from a population on the host plant spiraea and the R-clone selected from a population on the apple tree, the resistance ratio as expressed by RIS ratio of $LC_{50}$ was 78 for phosphamidon and 546 for pirimicarb. Esterase zymogram determined by the agar gel electrophoresIs revealed a significant difference between the clones. The activity of the E2, E5, E6 and E7 of the R-clone was higher than that of the S-clone, It is suggesLed that the Increased esterase activity may be involved in the mechanism of insecticide resistance in the spiraea aphid, although the involvement of other factor(s) may not be ruled out.

• The Korean Journal of Pesticide Science
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• v.15 no.4
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• pp.417-433
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• 2011

The study tested QuEChERS (quick, easy, cheap, effective, rugged and safe) sample preparation and HPLC-MS/ MS analysis for measurement of pesticide residues in fruit and vegetable. 240 kinds of pesticides spiked at three levels of 90, 45, 9 ng/g in lettuce and apple. For QuEChERS sample preparation, graphitized carbon black (GCB) was used for only lettuce in dispersive-SPE as absorbent. Matrix-matched standard calibration was used for quantitative analysis of HPLC-MS/MS. 218 pesticides (91%) in apple and 207 pesticides (86%) in lettuce showed recoveries in the range of 70~120% with $RSD{\leq}20%$. The lowest calibrated level (LCL) were 4.5 ng/g for 192 pesticides, 9 ng/g for 42 pesticides, 45 ng/g for 3 pesticides and 3 pesticides were not detected at all concentration levels. The results showed that the QuEChERS sample preparation and HPLC-MS/MS analysis can be applied to multi-residue analysis of pesticides in vegetables and fruits.

• Research in Plant Disease
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• v.29 no.2
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• pp.145-157
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• 2023

Apple grower in the Cheongsong region, Korea has reported the increased loss of apple yield due to severe bitter rot incidence. We noticed that this indience is because the Colletotrichum population has developed resistance to commonly used fungicides. We isolated 39 Colletotrichum isolates from 13 orchards in Cheongsong, and all the isolated Colletotrichum species were identified as C. siamense or C. fructicola. These 39 strains were tested for mycelial growth and conidial germination against 12 fungicides. trifloxystrobin (30-55% in recommended concentrations) was shown lower inhibitory effect on mycelial growth. However, the inhibition of conidial germination was shown higher than mycelial growth (62-100%). Kresoxim-methyl was shown lower inhibitory effect on mycelial growth (29-55%). conidial germination inhibitory effect was shown 51% to 96%. dithianon was shown diversity response to inhibition of mycelial growth (43-100%). Tebuconazole was shown high inhibitory effect on mycelial growth (84-100%) and conidial germination inhibitory effect was shown to be 64 to 100%. metconazole has been found to display with high inhibitory effect on mycelial growth (79-100%) and conidial germination (70-80%). fluazinam was shown to possess high inhibitory effect on mycelial growth (87-100%) and conidial germination (94-100%). This study provides basic information for the effective management of apple bitter rot.

• Journal of Plant Biotechnology
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• v.46 no.4
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• pp.318-322
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• 2019

When dehulled apple seeds (Malus pilmila var. domestica) were induced to germinate, the rate of germination, which was increased by piercing both the radicle and cotyledon, was related to the site of injury. Also, the germination rates of an embryo with ¾ cotyledon (¾ CE), embryo with ½ cotyledon (½ CE), embryo with ¼ cotyledon (¼ CE), and embryo without cotyledon (NCE) gradually decreased compared to an embryo with a normal cotyledon, but it significantly recovered on the agar media containing MS solution and/or 80 mg/L gibberellin (GA₃) as nutrition. The results show that the germination of the embryo was inhibited by the partial removal of cotyledon and also demonstrated that the rate of germination could be significantly increased by adding GA₃ (80 mg/L) and/or MS medium.