• 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.

• Research in Plant Disease
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• v.28 no.2
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• pp.92-97
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• 2022

Apple stem grooving virus (ASGV) is a high-risk viral pathogen that infects many types of fruit trees, especially pear and apple, and causes serious economic losses across the globe. Thus, rapid and reliable detection assay is needed to identify ASGV infection and prevent its spread. A reliable reverse transcription loop-mediated isothermal amplification (RT-LAMP) was developed, optimize, and evaluated for the coding region of coat protein of ASGV in pear leaf. The developed RT-LAMP facilitated the simple screening of ASGV using visible fluorescence and electrophoresis. The optimized reaction conditions for the RT-LAMP were 63℃ for 50 min, and the results showed high specificity and 100-fold greater sensitivity than the reverse transcription polymerase chain reaction. In addition, the reliability of the RT-LAMP was validated using field-collected pear leaves. Furthermore, the potential application of paper-based RNA isolation, combined with RT-LAMP, was also evaluated for detecting ASGV from field-collected samples. These assays could be widely applied to ASGV detection in field conditions and to virus-free certification programs.

• The Korean Journal of Soil Zoology
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• v.6 no.1_2
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• pp.7-9
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• 2001

Six species of the phytoseiid mites were recorded from the pear field of Naju District in Korea: Amblyseius womersleyi, A. eharai, A. orientalis, A. makuwa, A. bakeri and Proprioseiopsis nemotoi. Of these, A. bakeri and p. nemotoi were previously unrecorded in this field, and genus Proprioseiopsis is recorded for the first time in Korea.

• Korean Journal of Organic Agriculture
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• v.26 no.2
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• pp.259-268
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• 2018

The study investigated the efficacy of four different essential oils on the repellent responses of large black chafer (Holotrichia parallela) Motschulsky (Coleoptera: Scarabaeidae) in organic pear (Pyrus pyrifolia) orchards. Cinnamon, pine, peppermint, and eucalyptus oils were used, and the behavioral responses and repellent effects against H. parallela were investigated under laboratory and field conditions. Adult beetle responses to different oils were examined using a Y-tube olfactometer in the laboratory and four absorbent blocks with each oil in the field. The repellent responses rates of H. parallela were 100% for cinnamon oil; however, only 67% of adult beetles avoided peppermint and eucalyptus oil in the Y-tube olfactometer bioassay. In the field tests, the least damage to leaves was observed on trees treated with cinnamon oil, whereas the most damage was observed in the control (non-treated) trees and those treated with peppermint oil, followed by eucalyptus and pine oil. Therefore, cinnamon oil can be used as a repellent to avoid damage form large black chafers in organic pear orchards.

• Korean Journal of Agricultural and Forest Meteorology
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• v.10 no.2
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• pp.58-64
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• 2008

This study was carried out to determine the availability of development rate(DVR) model for predicting bud break time of 'Niitaka' pear. In addition, the study also assessed the effect of an increase in temperature on predicting bud dormancy breaking time in winter season. The DVR model, which was developed for 'Kosui' pear, illustrated that the bud break time(e.g., Dec. 12-Dec. 19) of 'Niitaka' pear observed in the field corresponded to the predicted bud break time by DVR model. This result indicates that the bud break time of 'Niitaka' pear can be predicted by DVR model tuned for 'Kosui' pear. As the temperature increased during the winter season, the bud break time was delayed. Chilling requirement deficiency for the bud break time is expected in Jeju Province when the temperature increased above $4^{\circ}C$ in winter season.

• Korean Journal of Organic Agriculture
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• v.22 no.2
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• pp.347-357
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• 2014

This study was conducted to evaluate the control effect of sodium dichloroisocyanurate (NaDCC) for Venturia nashicola on Niitaka pear during flowering period. As a nontoxic disinfectant, sodium dichloroisocyanurate is widely used in the field of hygiene and disease prevention, medical treatment, aquiculture as well as plant protection. NaDCC was sprayed on the pear tree inoculated with conidia ($4.5{\times}10^5spores/mL$) of Venturia nashicola and as a result the incidence of pear scab was 23.8% in 750mg/L and 26.2% in 1,000mg/L compare to the 51.6% incidence in untreated tree. No damage in the pollen of pear flower was detected with NaDCC treatments in the full bloom period for six pear cultivar including Wonwhang. A NaDCC single treatment in the early bloom of Niitaka pear showed more than 98% of fertilization rate. Furthermore, there was no incidence of Venturia nashicola on Nitaka pear trees treated with NaDCC 4 times during their growth period.

• Animal cells and systems
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• v.16 no.2
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• pp.145-153
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• 2012

The pear psylla, $Cacopsylla$ $pyricola$ (Hemiptera: Psyllidae), is a serious insect pest of commercial pear crops. The species, which resides on pear trees throughout its life cycle, is rapidly spreading in some regions of the world. The population genetic structure of the species collected from several pear orchards in Korea was studied to understand the nature of dispersal and field ecology of the species. The 658-bp region of mitochondrial COI gene and the 716-bp long complete internal transcribed spacer 2 (ITS2) of the nuclear ribosomal DNA were sequenced. Unlike other previously studied insect pests, the COI-based genetic diversity of the pear psylla was extremely low (maximum sequence divergence of 0.15%). This finding allowed us to conclude that the species may have been introduced in Korea relatively recently. ITS2 sequence-based analyses of phylogeny, population differentiation, gene flow, and hierarchical population structure all concordantly suggested that the pear psylla populations in Korea are neither genetically isolated nor hampered for gene flow. These genetic data are concordant with the dispersal of an overwintering winterform morph outside the non-pear habitat in the fall.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2004.05a
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• pp.147-147
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• 2004

• Korean Journal of Organic Agriculture
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• v.26 no.2
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• pp.245-257
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• 2018

The efficacy of different control techniques against the large black chafer, Holotrichia parallela Motschulsky (Coleoptera: Scarabaeidae), in organic pear (Pyrus pyrifolia) orchards was evaluated. In this study, field trials were conducted in three locations in Korea-Naju, Hampyeong, and Boseong-to evaluate different techniques to suppress these beetles. Pheromone traps, bio-insecticides (Hongmengye and Melchungdaejang), and a combination of the two were applied as treatments. In Naju, Hampyeong, and Boseong, the highest number of adult H. parallela were caught in the control plots (n=45, n=39, and n=20, respectively), while the fewest were caught in the pheromone plus bio-insecticide plot (n=19) in Naju and in the combined treatment plot in Hampyeong (n=10). In Naju, the greatest leaf damage was observed in the control (66%), and in all locations (Naju, Boseong, and Hampyeong), the least damage occurred in the combined treatment plots (42%, 36%, and 24%, respectively). Regarding the tree canopy, the greatest leaf damage was observed in the upper canopy, and less damage was observed in the lower canopy. These results demonstrate that the combination of sex pheromone traps and bio-insecticides can be used to manage H. parallela in organic pear orchards.

• Journal of Biosystems Engineering
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• v.21 no.3
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• pp.336-342
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• 1996

A 4.1MHz$1^H$ Nuclear Magnetic Resonance(NMR) sensor was designed and manufactured to evaluate the internal quality of fruits. The magnet console having 963gauss magnetic field induction was used for the NMR sensor. To optimize and evaluate the NMR sensor, glycerol and sugar-water solutions were used. $^1$H(proton) resonance signals were used to estimate the sugar contents in fruits. Artificial neural network models were developed to predict sugar contents in fruits from the proton resonance signals. The standard errors of prediction(SEP) were 0.565(apple), 0.394(pear) and 0.415(kiwi), respectively. The result implied that it was possible to evaluate apple, pear and kiwi into 3 grades using the NMR sensor.