• The Plant Pathology Journal
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• v.37 no.6
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• pp.681-686
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• 2021

It is difficult to distinguish melanose and melanoses-like symptoms with the naked eye because they appear similar. To accurately detect melanose symptoms caused by Diaporthe citri from melanose-like symptoms, we developed PCR-based specific primers Dcitri by aligning the internal transcribed spacer (ITS) region of D. citri with the ITS of Diaporthe cytosporella, Diaporthe foeniculina, Colletotrichum gloeosporioides, Botrytis cinerea, Alternaria citri, and Fusarium oxysporum found on citrus peel. PCR results showed that the specific product was amplified in D. citri but not in other isolates including, C. gloeosporioides, B. cinerea, A. citri, F. oxysporum. In addition, specific products were observed in melanose symptoms caused by D. citri but not in melanose-like symptoms, such as copper-injury, sunscald, damages by yellow tea thrips, and pink citrus rust mite. Using the Dcitri primers developed in this study, it is expected that melanose caused by D. citri could be accurately distinguished from melanose-like symptoms.

• Research in Plant Disease
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• v.29 no.1
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• pp.82-87
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• 2023

Exogenous ferrous chloride (FeCl₂) suppressed in vitro growth of Ralstonia pseudosolanacearum, causing bacteria for tomato bacterial wilt. More than 50 μM of FeCl₂ reduced the in vitro bacterial growth in dosedependent manners. Two to 200 μM of FeCl₂ did not affect the fresh weight of detached tomato leaves at 3 and 5 days after the petiole dipping without the bacterial inoculation. The bacterial wilt of the detached tomato leaves was evaluated by inoculating two different inoculum densities of R. pseudosolanacearum (10⁵ and 10⁷ cfu/ml) in the presence of FeCl₂. Bacterial wilt in the detached leaves by 10⁵ cfu/ml was efficiently attenuated by 10-200 μM of FeCl₂ at 3 and 5 days post-inoculation (dpi), but bacterial wilt by 10⁷ cfu/ml was only reduced by 200 μM of FeCl₂ at 3 and 5 dpi. These results suggest that iron nutrients can be included in the integrated disease management of tomato bacterial wilt.

• Korean journal of applied entomology
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• v.52 no.4
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• pp.403-408
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• 2013

A survey of pest occurrence and status of farmer's pest management was conducted at 45 cymbidium farms in 10 major cultivation areas in Korea. The pest species collected from the cymbidium farms were identified as follows: Tetranychus urticae Koch, Frankliniella intonsa Trybom, Pinnaspis aspidistrae Signoret, Incilaria confusa Cockarel, Halyomorpha brevis Walker, Myzus persicae S$\ddot{u}$lzer, and Aphis gossypii Glover, Coccus hesperidum Linnaeus, Thrips flavus Schrank, and Thrips tabaci Lindeman. The two-spotted spider mite, T. urticae, was the key pest in cymbidium production, occurring on 45 farms, followed by scales (20 farms), slugs (6), thrips (8), aphids (5), and stinkbug (1). PCR-RFLP of the rDNA ITS2 region revealed that two thrips species, Thrips flavus Schrank and Thrips tabaci Lindeman, occur on cymbidium farms. Therefore, it is necessary for the cymbidium farmers to establish an integrated pest management system to meet quarantine standards.

• The Korean Journal of Pesticide Science
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• v.20 no.4
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• pp.281-285
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• 2016

This study was conducted to investigate the characteristics of oviposition and the effect of density suppression by yellow-colored sticky trap on Ricania shantungensis in blueberry. The occurrence of an egg mass of R. shantungensis in the upper, middle and lower region were 56.6~60.2%, 23.8~28.1% and 11.7~19.7%, respectively. The number of egg masses in the branch was investigated. Percentage of the branch with one egg mass was greatest (50.9%) than with two (20.5%), three (14.6%) and over four (14.0%). The effect of yellow-colored sticky trap to reduce the number of R. shantungensis egg masses in blueberry was also investigated. In a month after yellow sticky trap installation, 17.1 adults of R. shantungensis were attracted per trap. Moreover, the number of egg masses on a tree in yellow-colored sticky trap plot was much lower (0.4) than control (1.3). Consequently, this result shows that use of yellow-colored sticky trap may contribute to decrease ovipisotion rate of R. shantungensis in blueberry.

• Korean journal of applied entomology
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• v.58 no.4
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• pp.335-339
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• 2019

The white peach scale (Pseudaulacaspis pentagona) is a significant pest of trees belonging to the Rosaceae family. We investigated the effect of ten insecticides on hatching rate of first instar white peach scale larvae (crawlers). The insecticides are Dinotefuran WG, Benfuracarb WG, Pyrifluquinazon WG, Clothianidin SG, Buprofezin WP, Buprofezin+Imidacloprid SC, Buprofezin+Etofenprox WG, Buprofezin+Thiacloprid SC, Benfuracarb+Buprofezin WG, Acetamiprid+Buprofezin EC. We observed that several crawlers emerged in early May, with the average number being 45.7. Hatching period was approximately 14 days, and the hatching success rate was approximately 77.7%. Overwintering females produced an average of 58.7 eggs. All insecticides achieved 100% mortality in crawlers. Our results suggest that these insecticides can effectively control white peach scale when used at the crawler stage.

• Korean Journal of Agricultural Science
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• v.47 no.1
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• pp.139-161
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• 2020

The aims of this study were to classify the cultivation status of medicinal crop farmers and to obtain basic data on domestic medicinal crops. To this end, 406 medicinal crop farmers participating in farming education programs in 14 cities and counties were surveyed over 10 months. The results were as follows. First, the biggest difficulty farmers faced in the overall production of medicinal crops was a lack of cultivation skills. Second, in a detailed inquiry about each difficulty item, the most difficult problems were injury by continuous cropping of root-using crops, shortage of specific farm machinery, uncertain market prices, and lack of knowledge about pest control or the positive list system (PLS). Third, the profitability of medicinal crops increased with career experience. Among the farmers who earned profits, requests for education and technical guidance were the most important factors for profitability. Fourth, the results of the analysis suggest that to achieve stable cultivation of medicinal crops, the following items need to be addressed: development and supply of basic cultivation technologies, climate response, registration of pest control pesticides, a solution to the injury by continuous cropping, and contracting cultivation expansion. Additionally, to improve profitability, it is necessary to create conditions that enable the same crops to grow for a long time in one region.

• Horticultural Science & Technology
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• v.31 no.4
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• pp.512-516
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• 2013

Pear cultivar 'Sinhwa' (Pyrus pyrifolia var. culta Nakai) was originated from a cross between 'Niitaka' and Whasan' with the aims of improving the fruit quality and the traits of cultivation and of early maturing more than 'Whasan' cultivar at Pear Research Station of National Institute of Horticultural & Herbal Science, Rural Development Administration in 1995. 'Sinhwa' was preliminarily selected in 2004 and named in 2009. The tree shows vigorous growth habit and semi-spread characters like 'Niitaka'. Furthermore, it has a sufficient and well upkeep of the flower bud, so it can be more easily cultivated in orchards. In the flower characteristics, flowering time of 'Sinhwa' is $11^{th}$ April like as maternal parent 'Niitaka'. Also 'Sinhwa' has short of pollen grains, so it is need above two pollinizer cultivars. 'Sinhwa' is highly resistant to black leaf spot (Alternaria kikuchiana) and relatively strong to pear scab (Venturia nashicola) in field condition. The optimum harvest time is around Sep. $15^{th}$ in Naju, which is ahead of 'Whasan' about 10 days in the harvest period. The fruit shape is oblate and fruit skin color is yellowish-brown during harvesting time. The average weight of fruit is 627 g, and the soluble solids content is $13.0^{\circ}Brix$. The flesh is very soft and juicy, and renders good eating quality. Shelf life is about 30 days under the room temperature condition.

• Research in Plant Disease
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• v.11 no.2
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• pp.193-197
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• 2005

The effect of pH on the survival of R. solanacearum and its transmission via roots of tomato in hydroponic culture were studied in laboratory and greenhouse. In laboratory experiment, R. solanacearum could not survive for 24h in nutrient solution with pH of $4{\cdot}0;or\;4{\cdot}5$, while 1, 14, 51 and $62\%$ of inoculum survived at pH $5{\cdot}0,\;5{\cdot}6\;and\;6{\cdot}5$, respectively. When tomato plants were inoculated with R. solanacearum through wounds on the stems, the bacteria moved downward from the inoculation site to the roots and infectious bacteria were released from the roots into the nutrient solution. Of two pH regimes tested in greenhouse nutrient-film technique(NFT) culture, the R. solanacearum population was significantly lower in pH 5.0 than in pH 6.5 in most sampling data. In treatments in which R. solanacearum was introduced by transplanting two root-inoculated plants, significantly move plants developed wilt at pH $6{\cdot}5$(34 out of 48 plants) than at pH 5.0(11 out of 48 plants). In addition, when the bacterium was introduced by transplanting two stem-inoculated plants at pH $6{\cdot}5$, seven out of 24 plants developed wilt.

• Korean journal of applied entomology
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• v.53 no.3
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• pp.281-286
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• 2014

In grape vineyards, whitish spots in a cloud shape have been often observed on the fruit surface recently. However, the cause of the halo spot symptom was unknown, hindering countermeasures to be properly designed for the control. A small hole in the middle of the formless halo spot remained as a scar formed by oviposition of the thrips. It became later a suberized scab, which is separated from the epidermal cells on the surface either to be retained on or to be detached from it as time proceeds. Such a symptom is distinguished from the feeding damages caused by thrips or true bugs occurring on the grape fruits. With DNA extracted from the egg-shell found in the hole, molecular diagnosis by amplifying an ITS2 region with universal primers and subsequently digesting the PCR product by an restriction enzyme (RsaI) revealed that the egg was laid by Frankliniella occidentalis. In addition, a mitochondrial COI sequence confirmed that the halo spot symptom was formed by its oviposition. This study provides accurate information on the peculiar damage symptom caused by oviposition of F. occidentalis that could be useful in the control strategies for this pest in vineyards.

• Korean journal of applied entomology
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• v.55 no.4
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• pp.389-403
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• 2016

Sugar beet nematode (Heterodera schachtii Schmidt) was first detected in 2011, in Chinese cabbage grown in the highland areas of Korea. Chemical control of the nematode by nematicides is not feasible due to its cyst-forming characteristics; therefore, the cultivation of non-host crops is a preferable alternative to utilize nematode-infected fields. In this study, a total of 276 plant cultivars belonging to 18 different families were screened to evaluate their resistance to the nematode. Based on the number of cysts formed following nematode inoculation, the tested crops were classified into 3 levels: susceptible, moderately susceptible, and resistant/immune. Among the 276 cultivars tested, 106 cultivars were susceptible, 40 cultivars were moderately susceptible, and 130 cultivars were resistant/immune. Among the resistant/immune cultivars, cyst formation was not observed on eggplant, tomato, lettuce, perilla, carrot, celery, watermelon, oriental melon, cucumber, pumpkin, chives, onion, welsh onion, balloon flower roots, deodeok (Codonopsis lanceolata), Jandae (Adenophora triphylla), and bean. Therefore, these plants are regarded as immune to the cyst nematode. However, many crops belonging to Solanaceae, Asteraceae, Chenopodiaceae, and Poaceae families showed moderate susceptibility or immunity, depending on the crop or cultivar. This study provides a basis for alternative crop recommendations for sugar beet nematode cyst-infected farms in Chinese cabbage production areas.