• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2005.09a
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• pp.202-205
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• 2005

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.1
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• pp.153-158
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• 2016

A detection algorithm of fallen pear bags caused by natural disaster like heavy rain, typhoon, hurricane, etc. is presented in this paper. The algorithm is developed for the gray pear bags with printed characters which are widely used at pear farms at Sangju and Naju producing large quantity of pears for export. It sets a region of interest (ROI) at first and then eliminates the regions having chromatic color in ROI. Morphological operation and prior information are used to eliminate small noises and several unusual regions and finally the regions of fallen pear bags are remained. The remained regions are analyzed and counted to estimate the scale of damage. Test images are consisted of the images taken at pear farms of Sangju and Naju at 2014. Experimental result shows that the detection rate of pear bags is more than 90% and also the proposed system can be implemented in real-time using hand-held devices because of its simple and parallel architecture.

• Korean journal of applied entomology
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• v.44 no.1 s.138
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• pp.31-36
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• 2005

Adoxophyes spp. are the major rests of a pear. The larvae attack both leaves and fruits. (Z)-9-tetradecenyl acetate (Z9-14:Ac), (Z)-11-tetradecenyl acetate (Z11-14:Ac), (E)-11-tetradecenyl acetate (E11-14:Ac) and 10-methyldodecyl acetate (10me-12:Ac) have been reported as the sex pheromone components of the genus Adoxophyes. Our objective was to determine the difference in sex pheromone composition of three different A. spp. populations each from Cheonan, Sangju, and Naju area orchards in Korea. Gas chromatography (GC) analyses of pheromone gland extracts of virgin females confirmed the presence of two compounds (Z9-14:Ac and Z11-14:Ac) in Cheonan and Sangju populations, and four compounds (Z9-14:Ac, Z11-14:Ac, E11-14:Ac and tome-12:Ac) in Naju population. The Z9-14:Ac and Z11-14:Ac were detected in the ratio of 80:20 in the Cheonan population and 3:97 in the Sangju population. Females of Naju population produced sex pheromone blend consisting of Z9-14:Ac, Z11-14:Ac, E11-14:Ac and 10me-12:Ac at a ratio of 31:62:6:1. Field trapping tests in pear orchards with Z9-14:Ac and Z11-14:Ac indicated that maximum captures of the male were obtained with traps baited by 80:20 in Cheonan, 10:90 in Sangju, and 30:70 in Naju. These results suggest that there are remarkable geographical variations in the sex pheromone composition of A. spp. in pear orchards in Korea, and taxonomic classification of these species must be carefully assessed.

• The Korean Journal of Community Living Science
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• v.15 no.1
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• pp.27-33
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• 2004

Natural dyeing means coloring with dyes extracted from plants, minerals or animals found in nature. Natural dyeing provides calm and natural colors; it has antibacterial and deodorizing qualities; and the dyeing process is environmentally friendly. This study extracted natural dyes from young fruit by thinning out the superfluous fruits of Naju pear trees, and then examined its dyeing properties, the optimal dyeing conditions, and its color fastness for practical use. The results indicated that dyeing is ideal when it had Cu mordant treatment (5% concentration at 9$0^{\circ}C$, pH 4) for 50 min. The color fastness of natural dyes with Cu mordant treatment was very excellent after rubbing and dry cleaning, and also good after exposure to perspiration, light and washing.

• Mycobiology
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• v.35 no.4
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• pp.238-240
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• 2007

Anthracnose symptoms often occurred on fruits of Asian pear trees grown in Anseong, Naju, Seonghwan and Pyeongtaek in Korea during the harvesting period from 2000 to 2005. A total of 28 isolates of Colletotrichum sp. were obtained from the anthracnose symptoms. All the isolates were identified as Colletotrichum acutatum based on their morphological and cultural characteristics. Four isolates of the fungus were tested for pathogenicity to fruits of Asian pear tree by artificial inoculation. All the isolates induced anthracnose symptoms on the fruits by wound inoculation but not by unwound inoculation. The anthracnose symptoms induced by artificial inoculation were similar to those observed in the orchard. This is the first report of anthracnose of Asian pear tree caused by Colletotrichum acutatum.

• The Plant Pathology Journal
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• v.17 no.4
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• pp.231-235
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• 2001

From April to May 1998, Phytophthora rot on pear, which has not been reported in Korea before, became an epidemic in the southeast part of the country under abnormally higher temperature and prolonged rainy days. Average temperature was about $3^{\circ}$ higher than in normal years, and 29 days were rainy during the 2 months in the areas surveyed. Over 1,000 orchards estimated at about 270 ha in 19 cultivation areas were infected by the disease, which occurred on all parts of the tree such as leaves, shoots, branches, stems, and flower clusters. Among 43 isolates collected from various locations and plant parts, 41 were identified as Phytophthora cactorum while 2 were identified as P. cambivora based on their mycological characteristics. The representative isolates revealed strong pathogenicity not only to pear but also to apple and peach. Among 23 pear cultivars tested, 7 were estimated as susceptible, 4 were moderate, and 11 were resistant to the pathogen. Results suggest that Phytophthora disease on pear is a potential threat to pear cultivation when environmental factors are favorable to disease development.

• International Journal of Industrial Entomology and Biomaterials
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• v.25 no.2
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• pp.163-169
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• 2012

A decrease in pass ratio of Korean exporting pears causes several negative effects including an increase in pesticide dependency. In this study, we attempted to establish the pest forecasting management system, composed of weekly field forecasting by pear farmers, meteorological data obtained by automatic weather station (AWS), newly designed internet web page ($\underline{http://pearpest.jnu.ac.kr/}$) as information collecting and providing ground, and information providing service. The weekly field forecasting information on major pear diseases and pests was collected from the forecasting team composed of five team leaders from each pear exporting complex. Further, an abridged weather information for the prediction of an infestation of major disease (pear scab) and pest (pear psylla and scale species) was obtained from an AWS installed at Bonghwang in Naju City. Such information was then promptly uploaded on the web page and also publicized to the pear famers specializing in export. We hope this pest forecasting management system increases the pass ratio of Korean exporting pears throughout establishment of famer-oriented forecasting, inspiring famers' effort for the prevention and forecasting of diseases and pests occurring at pear orchards.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.3
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• pp.209-215
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• 2007

To improve the accuracy of frost warning system for pear orchard in a complex terrain in Naju area, the daily minimum temperature forecasted by Korea Meteorological Administration (KMA) was interpolated using a regional climate model based on topoclimatic estimation and optimum scale interpolation from 2004 to 2005. Based on the validation experiments done for three pear orchards in the spring of 2004, the results showed a good agreement between the observed and predicted values, resulting in improved predictability compared to the forecast from Korea Meteorological Administration. The differences between the observed and the predicted temperatures were $-2.1{\sim}2.7^{\circ}C$ (on average $-0.4^{\circ}C$) in the valley, $-1.6{\sim}2.7^{\circ}C$ (on average $-0.4^{\circ}C$) in the riverside and $-1.1{\sim}3.5^{\circ}C$ (on average $0.6^{\circ}C$) in the hills. Notably, the errors have been reduced significantly for the valley and riverside areas that are more affected by the cold air drainage and more susceptible to frost damage than hills.

• Journal of the Korean Geographical Society
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• v.43 no.1
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• pp.20-35
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• 2008

This study used crop data from statistics yearbooks in Naju and climate data from Gwangju weather station to investigate whether climate changes have had significant impact on crops. The sample crops are rice, barley, pear, radish, Korean cabbage and red pepper. The results showed that the changes in temperature have shifted crop phonology and affected crop growth. The rice and barley heading date were advancing and had negative correlation with average temperature over 30days before average heading date. The number of rice grains per unit area $(m^2)$ were decreasing while the number of barley grains per unit area $(m^2)$ were increasing because average temperature during grain filling period of rice (barley) was increasing (decreasing). Therefore, decreasing (increasing) yields of rice (barley) can be predicted by global warming. The sprouting, flowering and full flowering date of pear were advancing. The sprouting date of pear had negative correlation with average temperature from February to March and the flowering and full flowering date of pear had negative correlation with average temperature from February to April. The brix and weight of pear were increased and were most sensitive to August and September average temperature. An earlier blossom of pear trees holds the danger of damage by late frosts. The plant length of radish and chinese cabbage were decreasing and negatively influenced by maximum temperature on September. The fruit set numbers of red pepper were increasing recently and had positive correlation with minimum temperature on August. The growth of radish and Korean cabbage will be poor, but the growth of red pepper will be good by rising temperature.

• Korean journal of applied entomology
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• v.40 no.2
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• pp.117-123
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• 2001

The occurrence and damage by the oriental fruit moth, Grapholita molesta (Busck) were investigated on pear trees from 1996 to 2000 in the Naju, Korea. The number of overwintering larvae in pear trees considerably varied depending on the maturation time of varieties. The density of overwintering larvae on late cultivars such as Gamcheonbae and Okusankichi was high, but relatively low on early cultivars. Trunk and main branch of pear trees were main overwintering sites. In 1997, overwintering larvae began to pupate from middle February, and to emerge from late March. Male moths were caught in the sex pheromone traps from late March until early October with four peaks of flight in 1996~2000. In every generation larvae damaged both the shoots and fruits of pear tree, but the first and second generation larvae tended to damage mainly shoots, while most of the injured fruits were due to the third and fourth generation larvae. In pear fruits damaged by fruit moths, most of these were caused by oriental fruit moth larvae and none of pear fruits were damaged by peach fruit moth or pear fruit moth larvae in 1998~2000.