• The Plant Pathology Journal
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• v.33 no.4
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• pp.410-423
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• 2017

Pathological interrelations of two soil-borne diseases in cucurbits (watermelon, oriental melon, shintosa and cucumber) caused by Fusarium isolates (FI) and the root-knot nematode (RKN), Meloidogyne incognita were characterized by the fusarium disease severity index (DI), RKN gall index (GI) and eggmass index (EI) in inoculation tests using FI and RKN. Virulence of FI as determined by DI at 4 weeks after inoculation was mostly in the higher order of Fusarium proliferatum F6, F5 and Fusarium oxysporum f. sp. melonis or Fusarium oxysporum f. sp. niveum with no significant differential interactions among the cucurbits and RKN co-infection. Significant increases of DI due to RKN coinfection were noticed in watermelon and oriental melon infected with F. proliferatum isolates, suggesting the DI increase due to RKN coinfection may depend upon the virulence of FI relative to aggressiveness of RKN on the cucurbits. For the coinfection of FI and RKN, GI and EI were mostly reduced logarithmically with the increase of DI, largely more in EI than GI, in all cucurbits except for shintosa. Microscopic examination of the root tissues showed histopathological features characteristic to infection types; formation of fungal hyphae and/or spores and plant defense structures (tyloses and mucilage) in variable degrees and formation of giant cells at variable developmental stages and with variable cytoplasmic depletion or degeneration which were visualized in relations with the values of DI, GI and EI. These findings will be helpful to develop control strategies of the soil-borne disease complex based on their pathological characteristics.

• Horticultural Science & Technology
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• v.31 no.3
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• pp.371-379
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• 2013

Anthracnose disease caused by Colletotrichum orbiculare, induces severe damage to cucurbits worldwide. Resistance of 112 commercial cultivars of cucurbits to C. orbiculare was evaluated. Seedlings of each cultivar at 2- to 3-leaf stage were inoculated with C. orbiculare KACC 40809 by spraying spore suspension of the fungus at a concentration of $4.0{\times}10^5$ spores/mL. Among the 36 cultivars of cucumber, 'Asiastrike', 'Tongilbaedadagi', 'Daeseon', 'Cheongrokmatjjang', 'Nokyacheongcheong', and 'Asianogak' were moderately resistant and the others were susceptible. All the tested cultivars of melon (33) and watermelon (4) showed highly susceptible response to C. orbiculare. On the other hand, the squash cultivars (17) represented less susceptibility to the fungus than the other cucurbits. Of the squash cultivars, 'Gammirak' and 'Teotbat' were resistant and 12 cultivars were moderately resistant. Among the rootstocks for cucurbits, ten cultivars including 'JjeuyakaEX', 'Nunbusyeo', 'Union', 'RS111', 'Ganggeuntoza', 'Hwangjaetoza', 'NO.8', 'Shintoza', 'Bulpaetoza', and 'Newtype' showed high resistance to the anthracnose pathogen. From the results, the resistant cultivars could be used as sources of resistance to cucurbits anthracnose (C. orbiculare) in the future breeding programs.

• Journal of Food Hygiene and Safety
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• v.34 no.1
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• pp.87-93
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• 2019

Revision work on the Codex Classification of Foods and Animal Feeds was undertaken in 2007 and presently, revisions for most food groups have been completed. For vegetables, the work was conducted during 2014-2017, and the final draft revision was adopted by the $40^{th}$ Codex Alimentarius Commission (2017). Here, the revised classification of vegetable commodities is introduced in order to be utilized in various food-related fields, in particular, food safety regulation. The revised classification is briefly summarized as follows: Codex classified vegetables into 10 groups (Group 009-018): bulb vegetables (Group 009), Brassica vegetables (except Brassica leafy vegetables) (Group 010), fruiting vegetables, Cucurbits (Group 011), fruiting vegetables, other than Cucurbits (Group 012), leafy vegetables (including Brassica leafy vegetables) (Group 013), legume vegetables (Group 014), pulses (Group 015), root and tuber vegetables (Group 016), stalk and stem vegetables (Group 017) and edible fungi (Group 018). The groups are further divided into a total of 33 subgroups. In the Classification, 430 different commodity codes are assigned to vegetable commodities. Meanwhile, Korea's Ministry of Food and Drug Safety (MFDS) does not include potatoes, beans and mushrooms within a vegetable group. In addition, the MFDS divides one vegetable group into six subgroups including flowerhead Brassicas, leafy vegetables, stalk and stem vegetables, root and tuber vegetables, fruiting vegetables, Cucurbits, and fruiting vegetables other than Cucurbits. Therefore, care is needed in using the Codex Classification.

• Korean Journal Plant Pathology
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• v.13 no.2
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• pp.105-112
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• 1997

Didymella bryoniae, gummy stem blight fungus of cucurbits, has been known not to produce its pycnidium in vitro without irradiation. Various methods for producing pycnidiospores of the fungus as an inoculum have been used. However, those methods have not been verified in terms of efficiency of the productivity, activity and synchronous maturation of the inoculum. Therefore, a pycnidiospore production method in vitro that is highly reliable and reproducible has to be developed to obtain a large amount of inoculum for screening disease resistant varieties or effective fungicides. Here we standardized a mass-production technique for pycnidiospores of D. bryoniae in vitro by comprehensively finding the optimal conditions such as kinds and thickness of cultural medium, growing temperature, and quality and duration of irradiation as well as examining the activity and pathogenicity of the pycnidiospores reproduced. In brief, mycelial colony on the PDA plate was cultured at 26$^{\circ}C$ for 2 days under the darkness, and then the plate was irradiated under the UV light (12 hr/a day) for 2~3 days at the same temperature(26$^{\circ}C$). Two days after UV irradiation, a great number of pycnidia was simultaneously formed. This plate was subjected to darkness again for 4~5 days to mature pycnidiospores. We could obtain a large amount of inoculum that is synchronously matured in a short period of time through the above procedures.

• The Plant Pathology Journal
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• v.32 no.1
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• pp.70-76
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• 2016

The infectious full-length cDNA clone of zucchini yellow mosaic virus (ZYMV) isolate PA (pZYMV-PA), which was isolated from pumpkin, was constructed by utilizing viral transcription and processing signals to produce infectious in vivo transcripts. Simple rub-inoculation of plasmid DNAs of pZYMV-PA was successful to cause infection of zucchini plants (Cucurbita pepo L.). We further engineered this infectious cDNA clone of ZYMV as a viral vector for systemic expression of heterologous proteins in cucurbits. We successfully expressed two reporter genes including gfp and bar in zucchini plants by simple rub-inoculation of plasmid DNAs of the ZYMV-based expression constructs. Our method of the ZYMV-based viral vector in association with the simple rub-inoculation provides an easy and rapid approach for introduction and evaluation of heterologous genes in cucurbits.

• The Plant Pathology Journal
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• v.17 no.1
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• pp.45-51
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• 2001

A root rot/vine decline disease occurred naturally on bottle gourd-stocked watermelon, melon, oriental melon and squash grown in greenhouses, but not on these plants grown in fields. Self-rooted watermelon, cucumber, pumpkin and luffa were also proven to be hosts of the pathogen by artificial inoculation in this experiment. The pathogen was identified as Monosporascus cannonballus by comparing microscopic characteristics of fungal structures with those of previously identified fungal strains. Our field investigations showed that the temperature and electric conductivity of soil in infected greenhouses were higher and the soil moisture content was lower than in noninfected greenhouses. To investigate soil-environmental factors affecting disease development, greenhouse trials and inoculation experiments were conducted. The host plants inoculated and grown under conditions of high soil temperature and electrical conductivity ($35\pm2^{\circ}$, 3.2-3.5 mS) and with low soil moisture content (pF 3.0-4.5) were most severely damaged by the fungal disease. Since plants growing in greenhouses ae usually exposed to such environmental conditions, this may be the reason why the monosporascus root rot/vine decline disease has occurred only on cucurbits cultivated in greenhouses but not in field conditions.

• Environmental Engineering Research
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• v.24 no.3
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• pp.427-433
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• 2019

Sakarya is famous for cucurbit productions in Turkey and cucurbits can grow as big as 560 kg of weight per fruit in its agricultural areas. There is no or limited information about contaminant levels and profiles of the agricultural fields in Sakarya. The purpose of this study is to investigate the levels of polycyclic aromatic hydrocarbons (PAHs) (naphthalene, phenanthrene, pyrene, and fluoranthene) and heavy metal (As, Cd, Cu, Cr, Ni, Pb, Zn) concentrations of the selected fields. Total 33 soil samples were collected from 12 counties of Sakarya where both cucurbits have been produced and organochlorine pesticides have been applied to the fields for more than 30 y during the historical plantation periods. Heavy metal and PAH contents in the soil samples were measured by an Inductively Coupled Plasma Emission Spectroscopy and a Gas Chromatography-Mass Spectrometry. The highest phenanthrene, pyrene, and fluoranthene concentrations were measured as 63.50 ng/g, 134.34 ng/g, 140.0 ng/g, respectively in the soil samples from Geyve County. Cu, Ni, and Cr concentrations were measured as 108.2 mg/kg, 219.9 mg/kg, and 173.1 mg/kg, respectively in Geyve's samples which were also the highest and 2-7 times more than the limit values given in the Turkish Soil Pollution Control Regulation. Precautions need to be taken for Sakarya's agricultural fields which are an important milestone of Turkey's cucurbit and fruit productions since the contaminants can be accumulated in the fruits and edible parts of the plants.

• Korean Journal of Agricultural Science
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• v.45 no.4
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• pp.575-582
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• 2018

Bacterial fruit blotch (BFB) caused by Acidovorax citrulli is a devastating disease found in many cucurbits cultivation fields. The genetic diversity for 29 strains of A. citrulli collected from various cucurbits in South Korea was determined by DNA fingerprinting with a pathogenicity test, multi locus analysis, Rep-PCR (repetitive sequence polymerase chain reaction), and URP (universal rice primers) PCR bands. Two distinct groups (Korean Clonal Complex, KCC1 and KCC2) in the population were identified based on group specific genetic variation in the multi locus phylogeny using six conserved loci and showed a very high similarity with DNA sequences for representative foreign groups [the group I (CC1-1 type) and the group II (CC2-5 type)] widely distributed worldwide, respectively. Additionally, in the case of phaC, a new genotype was found within each Korean group. The KCC1 was more heterogeneous compared to the KCC2. The KCC1 recovered mainly from melons and watermelons (ratio of 6 : 3) and 15 of the 20 KCC2 strains recovered from watermelons were dominant in the pathogen population. Accordingly, this study found that two distinct groups of differentiated A. citrulli exist in South Korea, genetically very similar to representative foreign groups, with a new genotype in each group resulting in their genetic diversity.

• The Korean Journal of Mycology
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• v.27 no.3 s.90
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• pp.198-205
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• 1999

Cucurbitaceous vegetable crops grown in greenhouses in Korea were surveyed from 1995 to 1997. Incidence of Sclerotinia rot was as high as $30{\sim}70%$ at its maximum on Cucumis melo var. reticulatus (netted melon), Cucumis sativus (cucumber), Cucurbita moschata (pumpkin) and Cucurbita pepo (summer squash) but relatively low on Citrullus lanatus (watermelon) and Cucumis melo var. makuwa (oriental melon). Symptoms of Sclerotinia rot developed on stems of all the cucurbits, fruits of five cucurbits except C. lanatus, petioles of two Cucurbita spp. and leaves of C. moschata. A total of 126 isolates of Sclerotinia sp. were obtained from the lesions and identified as Sclerotinia sclerotiorum based on the morphological and cultural characteristics. The fungus was very frequently isolated from stems and fruits of the cucurbits but rarely from petioles and leaves. Six isolates of the fungus were pathogenic to six cucurbits tested although there was some difference in virulence among the isolates to some of the hosts. C. lanatus was the most susceptible to the isolates, whereas C. melo var. makuwa was the most resistant. C. melo var. reticulatus and C. sativus were relatively susceptible to the isolates, and C. moschata and C. pepo relatively resistant.

• The Plant Pathology Journal
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• v.17 no.6
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• pp.387.1-387
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• 2001