• Korean Journal of Environmental Agriculture
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• v.30 no.1
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• pp.16-23
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• 2011

BACKGROUND: This study was conducted to investigate the effects of different organic treatments and a chemical fertilizer on the soil chemical, physical, and microbial properties in an organic pear orchard. METHODS AND RESULTS: Control was referred as a NPK chemical fertilizer (15N-9P-10K) and organic treatments included compost containing with oil cake, compost containing with humic acid, and compost containing with chitin substance. All treatments applied at rates equivalent to 200 g N per tree per year under the tree canopy in March 30 of 2008 and 2009. Soil bulk density, solid phase, liquid phase, and penetration resistance were not significantly different among the treatments. Organic treatment plots had greater organic matter, total nitrogen, potassium, and magnesium concentrations compared to control, and the nutrient concentrations were not consistently affected by the organic treatments. Microbial biomass nitrogen and carbon, dehydrogenase, acid-phosphatase, and chitinase activities overall increased from March to August. Organic treatments, especially compost containing with oil cake or chitin aicd, increased the microbial variables compared to control. CONCLUSION(s): All the organic treatments consistently stimulated soil biological activity. The consistent treatment effect, however, did not occur on the soil mineral nutrition as the trees actively taken up the nutrients during a growing season, which would have diminished treatment effects. Long-term study required for evaluating soil physical properties in a pear orchard.

• Korean Journal of Organic Agriculture
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• v.18 no.3
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• pp.363-375
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• 2010

Sustainable farming systems have remarkably increased in Korea due to the increase of environmental concerns caused by the conventional systems. This study was performed on eight-year-old 'Niitaka' pear tree s to investigate the effects of different organic fertilizers on soil chemical and microbial properties and leaf and bud developments. Treatment and applications included 10 kg of rice bran (RB), 10 kg of coffee bran compost (CBC), 10 kg of Chitin incubated compost (Micro keeper$keeper^{(R)}$, CIC), and 30 kg of the mixture of the RB, CBC, and CIC (RCC). Control received 60 g of NPK (16-11-12) chemical fertilizer. The organic fertilizers increased organic matter, nutrient concentrations such as P, K, Ca, and Mg, and microbial biomass in soils compared to the control. RCC had the greatest specific leaf weight (SLW), and the other treatments did not have a significant difference for the SL W. Leaf P and K concentrations were different among the treatments, but they were not affected by the amounts of the soil nutrients. No differences were observed in the leaf Ca and Mg concentrations in the treatments. Organic fertilizers had greater chlorophyll contents than the control but had similar flower bud characteristics to the control.

• Horticultural Science & Technology
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• v.28 no.4
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• pp.545-551
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• 2010

The primary objective of this study was to determine the relationship between fruit quality characteristics and pithiness fruit occurrence for confirming occurrence factors of pithiness tissues in 'Niitaka' pears ($Pyrus$ $pyrifolia$ Nakai). Fruits were harvested 4 times in 1 week intervals from 160 days after full bloom (DAFB) to 181 DAFB. Harvested fruits were separated with the specific gravity by Archimedes laws. Also, with specific gravity level in pear fruit, sugar content, acidity, and texture profile analysis (TPA) were investigated. Final verifiability of pithiness fruit was approved by eye observation at 90 days after storage. Also, in ASS (Alcohol Soluble Solid) and AIS (Alcohol Insoluble Solid), calcium contents were investigated. Although the differences in sugar and organic acid content were not significant in fruits divided by gravity, flesh hardness was depressed in fruits that showed low gravity. These results were more conspicuous in late harvested fruits (at 174 and 181days after full bloom) which showed low gravity, representing less content of AIS content and calcium in ASS and AIS when compared with early harvest fruits. Fruits of lower gravity below 1.0 measured with dipping induced the progression of pithiness symptom up to 76%. Consequently, harvest timing is a more concise factor in pithiness fruit occurrence although those symptom also affected by storage condition. Furthermore, the cause of pithiness fruit occurrence by late harvest is due to the lower cell wall binding calcium.

• The Korean Journal of Pesticide Science
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• v.20 no.2
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• pp.133-137
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• 2016

In Korea, six mealybug species have been reported on pears. This study investigated the occurrence of mealybugs in 19 pear orchards from 2013 to 2014. Two species, Crisicoccus matsumotoi Siraiwa (Hemiptera: Pseudococcidae) and Pseudococcus comstocki Kuwana were mainly found. The dominant species was C. matsumotoi identified on 73% of infested fruit. Toxicities of 14 registered insecticides (Buprofezin+Acetamiprid EC, Buprofezin+Amitraz EC, Buprofezin+Clothianidin SC, Buprofezin+Dinotefuran WP, Buprofezin+Etofenprox WG, Buprofezin+Thiacloprid SC, Buprofezin+Thiamethoxam SC, Benfuracarb WG, Acetamiprid WP, Clothianidin SC, Dinotefuran WG, Thiacloprid SC, Thiamethoxam WG, Sulfoxaflor SC) commonly used to control P. comstocki were evaluated to C. matsumotoi nymphs and adults at the recommended concentration. As a results, all insecticides exhibited strong insecticidal activity with 100% mortality of both nymphs and adults. These results indicate that the 14 insecticides can be used in control for C. matsumotoi in field.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.6
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• pp.1107-1111
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• 2002

This study has been carried out to investigate the effects of the Phenolic compound on the hyperglycemic mice induced with strentozotocin (STZ). The effects of the phenolic compound were assayed by the changes of the blood glucose creatinine and blood urea nitrogen (BUN ) levels, and insulin-immunohistochemical staining and electron microscopical observation for $\beta$ -cells of the Langerhan's islet, under the same experimental conditions. For this purpose male mice were fed with phenolic compound (PA group, IS mg/kg/day; PB group, 90 mg/kg/day)in their diet while the control group received the same commercial diet, for 6 weeks. The blood glucose contents was examined by tail vein blood once a week for 6 weeks. Samples of the pancreas removed after that period were processed for the immunohistochemical identification of $\beta$ -cells as well as for measuring ultrastructural changes of $\beta$-cells. The levels of serum glucose were decreased significantly (p<0.05) on the PB group compared with the control and PA group. The blood BUN and creatinine levels are slightly decreased in the phenolic compound feeding groups compared with control group. The $\beta$-cells on Langerhnan's islet were destructed by administration of STZ, so that a few of insulin-positive cells were observed in the control group. A lot of insulin-positive cells were observed in the PB group compared with the control group. According to the electron microscopical observation $\beta$-cells are recovered from the damage in the PA group. The $\beta$-cell contained a lot of electron dense and pale granules compared with control group. These results suggest that administration of the pear phenolic compound to the mice helped recovery from the damage induced by STZ.

• Korean Journal of Food Science and Technology
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• v.37 no.6
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• pp.905-911
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• 2005

Physical properties and compositions of dietary fiber sources (DFS) from peels of Asian pear fruit, Hosui, Niitaka and Chuwhangbae, were examined at different growth stages, young, unripe, and ripe fruits, to investigate their use as functional ingredients. Total dietary fiber (TDF) contents of DFS prepared from peels of three cultivars at three stages were high, 74.00-88.38%, with most being insoluble dietary fiber. Total phenolic compound contents of DFS were 1.64-4.46mg/g, with those of Niitaka and Chuwhangbae increasing with growth stages. Density of DFS from young fruit was significantly lower than those from unripe and ripe fruits (p<0.05), because particle size of DFS increased with growth stages within cultivars. Water-holding capacity (WHC) and oil absorption were 3.11-6.03g water/g solid and 1.98-2.57g oil/g sample, respectively. Young fruits, which showed lowest WHC value, had highest oil absorption value. Particle size of DFS had significant correlation with density, WHC, and oil absorption (p<0.05). Physical properties of DFS were mainly influenced by cellulose and uronic acid.

• Korean journal of applied entomology
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• v.25 no.4 s.69
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• pp.209-213
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• 1986

Dominant aphid species and seasonal fluctuations of the colonizing aphids on apple tree, peach tree, and pear tree were examined without insecticide treatment during $1982{\sim}1984$ in Suweon. The dominant species among the colonizing aphids in each fruit tree were Myzus malisuctus in April-June and Aphis citricola in Aug.-Oct. on apple tree; Myzus persicae in early springtime and Hyalopterus pruni in May-Oct. on peach tree; Sappaphis piri in April-June, Oct. and Aphis citricola in July-Sept. on pear tree. M. malisuctus and A. citricola on apple tree showed 3 peaks a year; the former was early June, late Aug. and early Oct., the latter early June, middle Aug. and late Sept. M. persicae on peach tree showed peak on late May to early June, and H. pruni on middle June and middle Oct. S. piri and A. citricola on pear tree showed 2 peaks a year; the former was late May and late Oct., the latter early June and early Sept.

• Food Science and Preservation
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• v.23 no.5
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• pp.645-653
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• 2016

The objective of this study was to examine quality characteristics of a smoked duck marinated in natural curing agents containing extracts of pear by sugar, celery powder, and vitamin C. We evaluated the composition food additives residue and total plate count, chromaticity, sensory properties, total polyphenol contents, 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging effect of general smoked duck (GSD) and natural smoked duck (NSD). The nitrite ion, antioxidant and sodium glutamate of NSD were not detected. The lightness, yellowness and redness of the two smoked duck decreased significantly as growing longer storage days. The total plate count (CFU/g) of coliform bacteria of two smoked duck were not grown. The sensory properties showed that NSD was higher than GSD in the aspect of taste, texture and overall preferences. The total polyphenol contents and DPPH radical scavenging effect of NSD were higher than those of GSD. These results suggested that it was possible to manufacture a smoked duck marinated in natural curing agents including extracts of pear by sugar, celery powder, and vitamin C for the improvement of safety and quality.

• Korean journal of applied entomology
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• v.23 no.2 s.59
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• pp.82-88
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• 1984

Fruit rot and blister canker, a disease of apple occurring severely in Korea has been studied for correct identification of the syndrome In fruit and apple trees. Among the fungi isolated from blister cankers, rough barks or fruits showing rotting of 7 different host species were Botryosphaeria berengeriana (pycnidial stage. Dethiorella mali), Penicillium expansum and Alternaria sp. from apple rots and Phomopsis sp. from pear fruit rots. The most dominant isolates were B. berengeriana. Ten isolates of D. mali were grouped in to two conidial types based up mycelial growth rate, growth habits and mycelial coloration on PDA. None of 10 isolates was chromogenic. Pycnidia in apple stems, stromatic, dark brown, globose or subglobose and the measuring were $103.5-287.5{\mu}\times92.0-287.5\mu$. The pycnidia contained hyaline, nonseptate, fusiform conidia. The sizes of pycnidiospore of isolates obtained from apple twig were $4.3-7.2{\mu}\times20.0-31.5{\mu}(average\;5.9\times25.4\mu)$. Some conidia of this fungus from apple, pear, peach and ornamental cherry showed 1-,2-,3-septate before or during germination. Microconidia were observed in pycnidia on PDA and fruit lesion of inoculated host. Symptoms on leaves and fruits were contoured brown spots when inoculated. Wart-like protuberance were formed on the surface of apple and pear. Canker appeared on branches of peach and ornamental cherry inoculated.

• Korean journal of applied entomology
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• v.13 no.4 s.21
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• pp.209-216
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• 1974

Life history and control methods of Aphanostigma iakusuiense Kishida were studied during April to November, 1974, in the Naju pear orchard area, Cholla Namdo. The results are summarized as follows: 1. More than $60\%$ of wintering eggs were found at the height of 1.5 to 2.0m from the soil surface, with approximately $10\%$ at 0.5 to 1.5m and 1.5 to 2.5m respectively. 2. There was little difference in the size of egg masses and hatching ratio $(12.7-13.7\%)$ between the varieties of host trees, Mansamkil and Kooksoo. 3. Hatching was not observed until April 6, but hatches of $12.8\%$ on April 13 and $90.6\%$ on May 4 were found. 4. During the hatching season in early spring, 8 chemicals were applied to test effectiveness of control. C8514, Metasystox, Acar 338, and Parathion were more effective than either Sevin or Malix for control of this insect. 5. Highest populations of pear phylloxera ocurred from August 20 to September 20 at which time levels of eggs and larvae were simillar in abundance. 6. In tests for control of this insect after in paper bags, DDVP, Loxon, C8514, Sevin, and Binapacryl were more effective than either EPN or Otran. 7. Predacious mite, Protolaelape pygmaeus Miller, and several species of lady beetles (Coccinellidae) preying on this insect as natural enemies were collected. The predation ratio of mites varied according to region: that is 0.77 to $18.6\%$ in Bia Orchard; $7.88-48.7\%$ in Noan Orchard and almost none in Youngsanoo Orchard. 8. The varietal difference in fruit damage by this insect was in the order of Choseng Chuck, Kooksoo, followed by Sin Ko, Mansamkil, Keumchon Choo, and Changsimrang.