• The Plant Pathology Journal
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• v.22 no.3
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• pp.248-254
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• 2006

Pear black necrotic leaf spot (PBNLS) on pear trees (Pyrus pyrifolia) is caused by a Korean isolate of Apple stem grooving virus (ASGV-K). Yellow spots were detected in Phaseolus vulgaris (kidney bean) and Chenopodium quinoa which were grown near the diseased pears in year 2000 through 2003. The ASGV-K, the causative agent of PBNLS, was detected from the symptoms of the diseased kidney bean plant and C. quinoa. ASGV-harboring fungi were also isolated from symptomatic plants and from soils surrounding the infected plants. The ASGV-harboring fungus was identified and characterized as Talaromyces flavus. Ecopathological studies showed that the number of ASGV-harboring fungi on the pear leaves was not correlated with differences in temperature or severity of symptoms. Additionally, there was no difference in fungus frequency among the orchard locations or different host plants. Although the frequency of fungi isolated from the soil was not affected by changes in temperature or location, the fungi occurred at higher densities in the rhizosphere than in the plants themselves.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.209-214
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• 2012

This experiment was carried out to investigate the replaceability of chemical fertilizer by SCB liquid fertilizer (SCB) in pear orchard for 5 years. The effects on the mineral content of leaf, fruit quality, yield and soil chemical properties are as follows: The mineral content of leaf showed no difference between the treatments; two SCB liquid fertilizer treatments based on the N (SCB-N) and K (SCB-K) content, and control (chemical fertilizer application). There were no significant differences in yield, titratable acidity and weight of the fruit although the figure of fruit weight was high in SCB-N treatment. Soluble solids content was higher in the SCB treatments than the control. Soil chemical properties such as the content of soil organic matter, available soil phosphate and exchangeable cation were not different, although soil pH was higher in SCB treatments. In conclusion, it is suggest that the use of chemical fertilizer in pear orchard could be replaced by the application of SCB liquid fertilizer because of the same effect on the growth of pear tree and soil chemical properties.

• Korean Journal of Organic Agriculture
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• v.21 no.4
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• pp.617-627
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• 2013

This study was conducted to survey the current pest occurrence and grower's pest management practices, and to investigate biodiversity including birds, snakes, rodents, and amphibians in organic pear orchards. From the questionnaires and field survey of 22 organic orchards in 2010, the materials such as lime sulphur, plant extracts and their mixtures with microorganisms, and oils were preferred over insecticides. Scab, mealybugs, woollybugs and barkminers were the major pests for organic pear growers. Environment-friendly fungicides and insecticides were applied 9 to 10 and 5 to 6 times respectively. Incidence and severity of scab on Niitaka pear fruits in organic orchards was higher than in conventional ones. Whereas for mealybugs there was no significant difference between organic and conventional orchards. Pear fruits in organic orchards were significantly smaller than those of non-organic orchards. For the biodiversity of amphibians, snakes, pheasants, and rodents, there was no significant difference between organic and conventional orchards, but Rufous turtle doves were monitored more in organic areas than in conventional ones.

• Korean Journal of Organic Agriculture
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• v.24 no.4
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• pp.759-771
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• 2016

We compared the fruit set and the quality of the 'Niitaka' pear (Pyrus pyrifolia Nakai) among flowers pollinated by two bee species (Apis mellifera and Bombus terrestris) and pollinated artificial. The artificial pollination rate was 1.3 to 1.9 times higher than the bee pollination rate. Moreover, the artificially pollinated flowers produced fruit that was 5 to 10% higher in weight, 2 to 3% larger in size, and had a higher fruit shape index (L/D) than fruit pollinated by the bees. On economic analysis, net profit from insect pollinator was 93.5 to 97.1% of net profit from artificial pollination. Therefore, artificial pollination is more efficient than bee pollination in 'Niitaka' pear. However, regarding fruit quality and net profit, these results suggest that bee pollination can be an good alternative to artificial pollination in 'Niitaka' pear.

• The Korean Journal of Mycology
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• v.41 no.1
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• pp.33-37
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• 2013

To develop the functional pear fruitlet product, we prepared fermented pear fruitlet product (FPFP) from mixed fermentation of Saccharomyces cerevisiae, Kluyveromyces fragilis and Lactobacillus plantarum. Then, we investigated their several physiological functionalities. Among several physiological functionalities, antihypertensive angiotensin I-converting enzyme (ACE) inhibitory activity of the FPFP was the highest of 87.4% and its antioxidant activity was also showed 69.6%. FPFP from mixed fermentation by yeasts and Lactobacillus plantarum after thawing of frozen pear at $20^{\circ}C$ showed higher physiological functionalities than those of single fermentation by Saccharomyces cerevisiae or Bacillus subtilis after $40^{\circ}C$ of thawing.

• Korean Journal of Organic Agriculture
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• v.19 no.4
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• pp.543-551
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• 2011

This study was conducted to evaluate nutrient production of both orchardgrass and several clovers as a green manure in a 'Niitaka' pear (Pyrus pyriforia) orchard. The experiment was conducted at diligent farmer in Boseong in Chonnam on March 26 of 2010, and the treatments included; 1) orchard grass (2.0kg/$1,000m^2$), 2) orchard grass (1.0kg/$1,000m^2$)+ladino clover (1.0 kg/$1,000m^2$), 3) orchard grass (1.0kg/$1,000m^2$)+red clover (1.0kg/$1,000m^2$), and 4) orchard grass (1.0kg/$1,000m^2$) +white clover (1.0kg/$1,000m^2$). Lengths of orchardgrass and clovers were greater in July than those of June and September. Seeding of orchardgrass without clovers in June and July increased dry weight of green manure crops compared with the seeding of orchardgrass with clovers, resulting in greater annual total dry weight. Various green manure treatments produced different amounts of total N and $P_2O_5$ from each raw materials and did not satisfy amounts of those nutrients for proper annual growth of ten- to twelve-year-old pear tree. Amounts of $K_2O$ producing from green manures, however, satisfied for proper growth of the pear trees.

• The Korean Journal of Mycology
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• v.28 no.1
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• pp.49-54
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• 2000

This study was conducted to investigate the major mycotoxins occurred during storage from apple, peat, citrus and grape. Analyses of the mycotoxins were conducted by TLC and HPLC. Patulin was only detected from apple, pear, citrus and grape infected by penicillium mycotoxins, but citrinin did not detected. The detected amount except grape ranged from $5.68{\sim}46.81\;{\mu}g/g$ in apple, $3.48{\sim}84.7\;{\mu}g/g$ in pear, $0.16{\sim}0.27\;{\mu}g/g$ in citrus, respectively. When compared to the effect of control on penicillium mycotoxins during storage in apple, pear and citrus, sodium hypochloride gas and heat at $37^{\circ}C$ treatment exhibited effective control. Especially, heat at $37^{\circ}C$ treatment exhibited 100% effective control without any injuring by treatment. In pear and citrus sodium hypochloride gas treatment caused injury by treatment.

• Korean Journal of Organic Agriculture
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• v.17 no.4
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• pp.567-575
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• 2009

Organic pear (Pyrus pyriforia) fruits have remarkably increased in Korea since year 2000 due to increase consumer's demand for the fruit, and the farmers are keep trying to change their cultivation system that is replaced from conventional farming to organic-base farming for the fruit. However, there is little information for the soil properties, tree nutrition, and tree growth at organic orchards in Korea. Therefore, this study was established to investigate for the chemical properties of soils and leaf and bud characteristics of a conventional and organic pear trees in experimental orchards for two years. Commercial (Sanwool, YoungHwa Co., Korea) compost was applied to the orchard soils with conventional farming systems for two years for pear trees (10 to 15 year old trees) in KyungSan, Korea. The compost application increased pH, organic matter content, cation exchange capacity (CEC), and, microbial biomass in the soil. The compost treatment also increased specific leaf weight and foliar $P_2O_5$ concentration as well as leaf and floral bud sizes.

• Korean Journal of Organic Agriculture
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• v.21 no.3
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• pp.373-380
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• 2013

A severe pink mold rot on matured asian pear (Pyrus serotina Rehder) fruit occurred in the organic farmers' orchard in Jinju, Korea in October, 2012. Decay of pear fruit appeared as a softened water-soaked symptom that was easily punctured by pressure. Later pink mycelium appeared on the surface of pear fruit and produced a mass of powdery pink conidia spores. Optimum temperature for mycelial growth of T. roseum was $25^{\circ}C$. Conidia showed hyaline, smooth, 2-celled, thick-walled with truncate bases, ellipsoidal to pyriform, and characteristically held together zig-zag chains and $10{\sim}22(34){\times}6{\sim}10(12){\mu}m$ in size. Conidiophore was erect, colorless, unbranched type, and 4-5 ${\mu}m$ width. On the basis of mycological characteristics, pathogenicity test, and molecular identification with the ITS region, the causal fungus was identified as Trichothecium roseum (Pers.) Link ex Gray.

• Food Science and Preservation
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• v.5 no.4
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• pp.335-338
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• 1998

Weight loss of fear packed with corrugated paperboard box(FC) laminated with functional MA film after 60 days storage at 5$^{\circ}C$ was 1.0%, and that of LDPE, CE film was 0.6-0.7%, while that of control(Corrugated Paperboard box) was 2.8%. Total ascorbic acid content of pear ill MA films and FC package was higher than that of control. Titratable acid of control changed 37%, but that of the others packages changed below 27%. Soluble solid content of control changed 27%, while the others changed below 2%. Reference in overall appearence of pear were not found among packaging methods. Corrugated paperboard box(FC) laminated with Functional MA film can be used as packaging material for pear packaging.