• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.632-637
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• 1996

An expert system for cucumber disease and nutritional disorders(ESCD) was developed using HCLIPS in which several interface programs were added to CLIPS developed in NASA. The knowledges for constructing knowledge base was obtained from interviews with farmers, agrochemical vendors and employees of agrochemical company. The ESCD is able to diagnose eleven diseases and twelve nutritional disorders which farmers, agrochemical vendors and employees of agrochemical company. The ESCD is able to diagnose eleven diseases and twelve nutritional disorders which could frequently found in fields and greenhouses. Validation of ESCD by twenty -four experts proved a possibility of its practical use for diagnosing cucumber diseases and nutritional disorders in the future.

• Research in Plant Disease
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• v.22 no.1
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• pp.18-24
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• 2016

This study was conducted to elucidate the cultural and pathogenic characteristics of Cladosporium cucumerinum PT1 and resistance of 81 commercial cucumbers (Cucumis sativus). Cucumber leaves and fruits appeared as scab were collected from a plastic film house located in Pyeongtaek, Gyeonggi-province, Korea in late March, 2015. A casual fungus was isolated from the diseased fruits on potato dextrose agar and it was identified as C. cucumerinum PT1 based on the morphological characteristics. To find out the effect of wounding and fruit size on the development of cucumber scab, small (<10 cm long), medium (10 to 20 cm long), and large (>20 cm long, commercially mature fruit) size cucumber fruits were harvested, C. cucumerinum PT1 pathogens were inoculated with a single droplet of suspension ($1{\times}10^5$ spores/ml) on wounded or unwounded cucumber fruits. Small fruits were completely damaged with showing severe water-soaking symptoms and fast pathogen growth regardless of wounded or unwounded. Meanwhile slight water-soaking symptoms on medium and large size fruits occurred and disease development into plant tissues was observed only on wounded fruits. Disease resistance of 81 commercial cucumber cultivars was evaluated on third-stage seedlings and small fruits by inoculating suspension ($1{\times}10^5$ spores/ml) of C. cucumerinum PT1. As a result, mini and pickling cultivar groups were resistant, 'Cheoeumcheoreom' cultivar was symptomless and the other cultivars were resistant to medium resistant. On the other hand, most of cucumber cultivars belonging to the other groups were susceptible. Disease resistance of cucumber against cucumber scab was significantly different among cultivars and a few cucumber cultivars showed different disease resistant responses to two bioassay methods using seedlings and small fruits. Therefore, to screen scab resistance in cucumber, a test using both fruits and seedlings is advisable. We think that the selected resistant cultivars can be used to control cucumber scab effectively under the farmhouse condition.

• Journal of Microbiology and Biotechnology
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• v.17 no.12
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• pp.2071-2075
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• 2007

Fourteen Bacillus thuringiensis isolates having both insecticidal activity and in vitro antifungal activity were selected and tested for in vivo antifungal activity against tomato late blight, wheat leaf rust, tomato gray mold, and barley powdery mildew in growth chambers. All the isolates represented more than 70% disease control efficacy against at least one of four plant diseases. Specifically, 12 isolates exhibited strong control activity against barley powdery mildew. Under glasshouse conditions, four (50-02, 52-08, 52-16, and 52-18) of the isolates also displayed potent control efficacy against cucumber powdery mildew. To our knowledge, this is the first report of B. thuringiensis isolates that have disease control efficacy against powdery mildew of barley and cucumber as well as insecticidal activity.

• Research in Plant Disease
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• v.30 no.2
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• pp.189-193
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• 2024

Cucumber (Cucumis sativus L.) is substantial economic importance in South Korea, with its cultivation occupying a significant portion of agricultural land. However, sustainable cucumber production requires effective management of various diseases affecting the crop yield. In this study, we explored the potential of Streptomyces sp. S20-465-derived metabolites in controlling cucumber anthracnose disease caused by Colletotrichum orbiculare. This study identified 4-hydroxy-4-methyl-2-pentanone as a potent antifungal compound present in the n-hexane extract of Streptomyces sp. S20-465 culture filtrate. This compound exhibited significant the disease reduction, demonstrating their potential as control agents. Our findings suggest that Streptomyces sp. S20-465-derived metabolite could serve as an effective tool for managing cucumber anthracnose, offering a sustainable approach to enhancing cucumber production. Further research into the application and efficacy of these compounds in agricultural system will be conducted.

• Research in Plant Disease
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• v.10 no.2
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• pp.121-125
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• 2004

An epidemic of target leaf spot of cucumber (Cucumis sativus) occurred in commercial greenhouses in Korea in 2000/2001. The early symptoms on the leaves were small brown spots with yellow halos. These lesions became irregular enlarging in diameter and eventually defoliation resulted. The causal agent was a fungus with morphological characteristics matching Corynespora cassiicola. The sequence of the ITS region of C. cassiicola CM2000-1 was identical to that of an authentic strain of Corynespora cassiicola. Optimal germination of spores and mycelial growth on plate was at 3$0^{\circ}C$. A long dew period on the leaf surface and high temperatures were the main contributing factors for disease development and the greenhouse epidemic. Artificial inoculation of the Korean isolate of C. cassiicola revealed resistance in some Korean cucumber cultivars.

• Research in Plant Disease
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• v.10 no.4
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• pp.313-318
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• 2004

Internal fruit rot of cucumber was observed in several locations in Korea. Incidence of the disease reached up to 21.5% and averaged 4.2% in the fields surveyed. The disease started at blossom ends of cucumber fruits. Internal tissues of infected fruit tips showed brown discoloration over 2 cm in length and 2 mm in diameter. Subsequently, the brown discoloration was extended into the carpels, and the surface of the infected fruit tips was rugged. Fungal isolates from the internal tissues of diseased fruits were identified as Didymella bryoniae based on mycological characteristics. Temperature for mycelial growth of isolates ranged $5{\sim}32^{\circ}C$ with optimal temperature between $26{\sim}28^{\circ}C$. Similar symptoms were developed in the internal part of the cucumber fruit when conidial suspensions of the isolates were inoculated to the flower of cucumber. Furthermore, Didymella bryoniae isolates from other plant parts of cucumber, watermelon, oriental melon, melon and pumpkin also showed the similar symptoms in the internal part of cucumber fruits by inoculation tests. Temperature range for occurrence of internal fruit rot of cucumber was $10{\sim}32^{\circ}C$ with optimal temperature of $25{\sim}28^{\circ}C$.

• Korean journal of applied entomology
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• v.21 no.3 s.52
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• pp.153-158
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• 1982

The study was conducted to obtain the basic information on the diseases epidemics of vegetable crops grown in Namji, Jinju, Gimhae and Suncheon under the extremely varied and specified conditions, plastic film house. The disease survey was conducted from the end of April, 1951 to April 1982. Leaf mold and late blight were serious foliar disease in tomato during the seedling stage, especially when the infected seeds were sown. The diseases increased rapidly 35 days after seeding. In both continuous cultivation of cucumber and rotation with upland crops, incidence of Fusarium wilt was severe while incidence of the disease was negligible in cultivations after paddy rice or grafting on pumpkin. Downy mildew of cucumber was severe in Jinju and Suncheon area, however, it was not so serious in Namji area where the growing season of cucumber was unfavorable for the maximum disease incidence. Cucumber mosaic virus disease was prevalent in the areas surveyed and the disease incidence was increased rapidly after June. Powdery mildew prevailed at the early stage of cucumber growth after transplanting in Namji area. Root rot and wilting caused by Phytophthora capsici was as the most destructive disease in pepper grown under the vinyl house, especially in Namji and Jinju area where the pepper has been cultivated intensively. The Phytophthora attacked most parts of young plants during the winter time and then induced crown rot on the adults plants. Cultivation of pepper in vinyl house was almost impossible because of the Phytophora disease by the end of June. Virus diseases to tomato plants were prevalent throughout the surveyed area and the damage was also severe. In Jinju and Gimhae area leaf mold and late blight showed high infection rate in tomato during the harvest time.

• Research in Plant Disease
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• v.10 no.1
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• pp.78-81
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• 2004

The resistance of 10 varieties of cucumber (Cucumis sativus L.) to powdery mildew, caused by Sphaerotheca fusca, was evaluated by a leaf disk assay. Leaf disks (10 mm in diameter) were removed from fully expanded leaves and then placed in petri dishes containing 0.16％ water agar amended with benzimidazole. Leaf disks were inoculated by dropping a 10 $\mu$l of conidia suspension. Conidiophore formation of powdery mildew was the greatest at $25^{\circ}C$. The response of the host to powdery mildew, based on the inoculation onto disks of the first leaf, highly correlated with results obtained from harvesting stage of cucumber plants in greenhouse test (r = 0.99$^{**}$). It is indicating that a leaf disk assay may precisely predict the response of cucumber plant to S. fusca.a.

• Research in Plant Disease
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• v.15 no.2
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• pp.68-71
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• 2009

Cucumber green mottle mosaic virus (CGMMV) was not infected in figleaf gourd by sap inoculation. However CGMMV was detected by RT-PCR from the figleaf gourd collected from a field growing cucumber grafted onto figleaf gourd in Cheonan, Chungcheongnam Province in 2008. Which field showed 100% infection rate of the virus disease. In the experiment grafted with cucumber onto figleaf gourd, transportation of CGMMV through cucumber to figleaf gourd was confirmed by RT-PCR when the virus was mechanically inoculated on the leaves of the cucumber. The amplified DNA concentration of the virus on electrophoresis gel was much higher in the cucumber than in the figleaf gourd. However, the virus particles from the figleaf gourds were not observed under electron microscopy, also sap of the figleaf gourds was not transmittable to Nicotiana benthamiana. To identify the existence of CGMMV particle, the virus was purified from figleaf gourd and cucumber growing together in the graft system. CGMMV solution extracted from the cucumber represented a typical absorption spectrum of the virus but that from the figleaf gourd did not. Only a few CGMMV particles were observed in the purified preparation from the figleaf gourd. These results confirmed that CGMMV only passed through figleaf gourd in the grafting system. This study indicated that figleaf gourd is not a host of CGMMY.

• The Korean Journal of Pesticide Science
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• v.7 no.3
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• pp.223-227
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• 2003

Survey on plant diseases occurring on cucumber cultivated in plastic film house of experimental farm in Suwon was conducted. Through the survey, occurrence of damping-off, downey mildew, powdery mildew and Fusarium wilt was observed. Especially downey mildew caused by Pseudoperonospora cubensis was the most severe foliar disease of cucumber. To control the disease effectively, effects of installation of ventilation fan and optimal spray timing of a chemical, dimethomorph+copper oxychloride WP, were investigated. Two ventilation fans installed at the front and at the back of plastic film house reduced air relative humidity by about 6.4% and downey mildew incidence by 55.7%. Downey mildew incidence on cucumber from untreated chemicals plot in plastic film house installed with ventilation fan was on a equal level with that from treated chemicals plot with three times application of dimethomorph+copper oxychloride WP in plastic film house without ventilation fan. Meanwhile in order to select optimal chemical application time, dimethomorth+copper oxychloride WP was treated three times at 7 days-interval from three days before the disease occurred, right after the disease occurred, and two days after the disease occurred, respectively. The result showed that dimethomorth+copper oxychloride WP applied to cucumber leaves and stems from three days prior to, right after, two days after occurrence of downey mildew reduced downey mildew incidence by 72.9, 61.8, and 23.7%, respectively. The above results showed that regulation of environmental factors like air relative humidity and preventive application of chemicals should be considered to establish control strategy to downey mildew.