• The Korean Journal of Mycology
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• v.27 no.4 s.91
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• pp.280-282
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• 1999

A new disease on mask melon grown under plastic film houses was found in Namhae area in May of 1999. Gray to dark brown mold were grown on the surface of matured fruits and infected inside tissues were discolored and rotten. Basal part of the fruit and blossom-end were frequently infected and colonized by fungi. About 2.2% of matured fruits were infected in the surveyed plastic film houses. The causal organism was isolated from the lesion and identified as Botrytis cinerea. The conidia in mass were hyaline or gray, 1-celled, mostly ellipsoid or ovoid and sized $8.8{\sim}21.2{\times}6.5{\sim}13.1\;{\mu}m$. Hyaline or pigmented conidiophores were tall, slender and determinated and, sometimes branched irregularly in upper part. Enlarged or rounded apical cells bear conidial cluster and sized $18.4{\sim}81.1{\times}4.3{\sim}11.4\;{\mu}m$. Optimum temperature for mycelial growth was recorded at $15{\sim}25^{\circ}C$. This is the first report on gray mold of melon caused by Botrytis cineria in Korea.

• Korean Journal of Environmental Agriculture
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• v.25 no.1
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• pp.85-92
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• 2006

Fungicides including keroxym-methyl (strobilurin fungicide), fenarimol and trifulmizole (DMI, boscalid (anilide) and metrafenone (benzophenone) were evaluated for preventive and curative efficacies against powdery mildew on oriental melon. The fungicides were applied preventatively at 7 days, 3 days and 3 hours before inoculation. Curative applications were made by applying fungicides three times at the interval of one week when infected leaves by powdery mildew were about 16% or 30%. Then preventative and curative efficacies were evaluated one week after inoculation and final application, respectively. Boscalid and metrafenone showed preventive efficacies of 74.3 and 68.3% against powdery mildew development respectively, when treated at 7 days before inoculation. They showed 89.4 and 87.2% efficacies when treated at 3 days before iniculation and 98.5 and 93.2% at 3 hours before inoculation respectively. However, there were no preventive efficacies in kresoxym-methyl, triflumizole and femarimol (DMI fungicides) when trebled at both 7 and 3 days before inoculation. At the preventive treatment 3 hours before inoculation, they indicated 59.0, 42.5, and 37.2% efficacies, respectively. When leaves were infected about 30% by powdery mildew, curative application of boscalid and metrafenone showed 85.9 and 74.0% of efficacies, respectively. Curative efficacies of kresoxym-methyl, tiflumizole and fernarimol were 5.5, 23.0 and 46.7% respectively. When leaves were infected about 16%, curative application of boscalid and metrafenone showed 100 and 97.5% of efficacies, respectively. However, the triflumizole and fernarimol showed relatively low curative efficacies of 30.8 and 51.6%, respectively. Microscopic observation of mycelial growth and conidia formation after detection of powdery mildew disease indicated lysis of mycelium and these lysis suppression of conidia formation showed tendency in accordance with curative efficacies of fungicides.

• Journal of Bio-Environment Control
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• v.31 no.1
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• pp.43-51
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• 2022

This study was conducted to investigate the effect of ventilation at high temperature on the control of powdery mildew, silverleaf whitefly two-spotted spider mite occurred at Korean melon cultivation greenhouse, and on leaf rolling and flowering of the plant in summer season. 'Alchanggul' grafted onto 'Hidden Power' rootstock was planted on soil bed with the distance of 40 cm. Three ventilation temperatures of 45℃, 40℃, and 35℃ as set points were compared. Ventilation treatment was done by control of side window operation from 18th June to 13th July when silverleaf whitefly, mite, and powdery mildew were occurred in all greenhouses. The temperature inside greenhouse was increased up to the set temperature point on sunny days and maintained for about 9 hours with high relative humidity at 45℃ condition. The differences of day maximum air temperature and day minimum RH were the highest at 45℃ treatment. After 11 days of treatments, the damage by powdery mildew and two-spotted spider mite was almost recovered at 45℃ treatment but not at 40 and 35℃. The population of silverleaf whitefly and two-spotted spider mite were significantly decreased at 45℃ treatment at 14 days after treatment, while powdery mildew symptom was not significantly decreased. Leaf rolling was observed at high temperature but not severe at 45℃ treatment. After 26 days of treatments, female flowers did not bloom at all at 45℃ treatment, and the number of male flowers was 1.2 among 15 nodes of newly grown shoots. As the result, it indicates that ventilation at the high temperature of 45℃ for about 2 to 3 weeks can be an applicable method to control above mentioned pests and disease, and to recover the vegetative growth of Korean melon by reducing flowering of the plant.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.668-675
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• 1998

These surveys were conducted to check the occurrence of disease in various horticultural crops in alpine areas, especially Daekwallyong areas, Pyongchang-Gun, and Hyeongseong-Gun in Kangwon province. TuMV on Chinese cabbage was one of the most serious diseases, especially in 1994 and 1997. The incidence of soft rot and clubroot has been increased gradually. Brittle root rot on Chinese cabbage was significantly decreased. Soft rot, gray mold, downy mildew, powdery mildew, bottom rot and Alternaria leaf spot were the common diseases on most vegetable crops. Gray mold (Botrytis cinerea) on celery, cercospora leaf spot (Cercospora sp.) on melon, powdery mildew (Erysiphe cichoracearum) on lettuce, and clubroot (Plasmodiophora brassicae) on parsley are newly found in Korea. The most common and predominant diseases were viruses, especially CMV, TMV, TuMV, BBMV, and gray mold, wilts, and cercospora leaf spot on many flowers in alpine areas. Fusarium oxysporum f. sp. eustomae causing wilting on lisianthus (Eustoma grandiflorum), Turnip mosaic virus causing mosaic and color breaking on stock, Cercospora spp. causing cercospora leaf spot on various wild lily, Cladosporum echinulatum causing leaf spot on carnation, and phytoplasma causing witches' broom on statice (Limonium sinuatum) and blazing star (Liatris spp.) were newly found during these surveys in Korea.

• Research in Plant Disease
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• v.21 no.2
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• pp.82-88
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• 2015

Acidovorax citrulli, the causal agent of bacterial fruit blotch, has caused an economically destructive damage in cucurbits cultivation fields worldwide. To consider more effective disease management, 33 A. citrulli isolates collected from various cucurbits in Korea were analysed by multi-locus phylogeny using five conserved loci(16S rRNA, adk, gltA, glyA, pilT). Two distinct groups (KCC1 and KCC2) in the population were identified on the base of group-specific genetic variation. Out of them, the predominant group was KCC2 and both groups included isolates from melon, cucumber and watermelon. Sixty-four percent of KCC1 isolates were recovered from non-watermelon hosts and seventy-two percent of KCC2 isolates from watermelon. This study presented that there was genetic differentiation among A. citrulli population in Korea. Also, these results will be applied as a very useful data in effective disease management.

• Research in Plant Disease
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• v.18 no.4
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• pp.277-289
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• 2012

The total number of requests and associated specimens for the diagnosis of virus infection were 573 and 2,992, respectively, on crops from agricultural places of farmers, Agricultural extension services and so forth for 5 years from 2007. The total number of virus tests was 13,325. The number of species of viruses infected on the submitted crops was 21 in 2007, 15 in 2008, 23 in 2009, 21 in 2010 and 17 in 2011. The newly recorded viruses were Tobacco leaf curl virus (TbLCV) in 2007, Tomato yellow leaf curl virus (TYLCV) in 2008, Impatience necrotic spot virus (INSV) and Radish mosaic virus (RaMV) in 2009, and Beet western yellows virus (BWYV) in 2010. Forty virus species including Alfalfa mosaic virus were detected over 5 years. The ten most frequently detected virus species were Cucumber mosaic virus (CMV), Tomato spotted wilt virus (TSWV), Tomato leaf curl virus (TYLCV), Cucumber green mottle mosaic virus (CGMMV), Broad bean wilt virus 2 (BBWV2), Zucchini yellow mosaic virus (ZYMV), Melon necrotic spot virus (MNSV), Pepper mild mottle virus (PMMoV), Watermelon mosaic virus (WMV) and Pepper mottle virus (PepMoV). The types of crops submitted from agricultural places were 51 in total and the ten most frequently submitted crops were red pepper, tomato, paprika, watermelon, melon, rice, cucumber, corn, radish and gourd. The total request rate for the top 10 crops and top 20 crops was 81.6% and 94.2%, respectively. Eight pepper infecting virus species included CMV, and the average infection rate was 24.6% for CMV, 18.9% for PMMoV and 14.7% for TSWV. Seven kinds of double infection were detected in pepper including BBWV2+CMV at 14.7% on average, and four types of triple infection including BBWV2+CMV+PepMoV at 0.9% on average. Six virus species detected on tomato including TYLCV, and the average infection rate was 50.6% for TYLCV, 14.5% for TSWV and 10.9% for Tobacco leaf curl virus (TbLCV). The mixed infection of CMV+TSWV on tomato was 3.9% on average and of Tomato mosaic virus (ToMV)+TYLCV was 0.4% on average. Five viruses detected on watermelon included MNSV and the average infection rate was 37.0% for MNSV, 20.4% for CGMMV, 18.1% for ZYMV and 17.8% for WMV. The mixed infection rate on watermelon was CMV+MNSV and WMV+ZYMV having an average infection rate of 0.7% and 5.0%, respectively. The average infection rates on melon were 77.6% for MNSV, 5.6% for CMV and 3.3% for WMV. Mixed infections of CMV+MNSV occurred on melon with an average infection rate of 13.5%.

• The Plant Pathology Journal
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• v.34 no.5
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• pp.426-434
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• 2018

During the spring season of 2014, a total of 148 melon and watermelon leaf samples were collected from symptomatic and asymptomatic plants in the western and southwestern regions of Saudi Arabia and were tested for the presence of Watermelon chlorotic stunt virus (WmCSV) and other suspected cucurbit viruses by double antibody sandwich enzyme-linked immunosorbent assays. Ninety-eight samples were found to be positive for the presence of WmCSV, nine samples were positive for the presence of Cucurbit yellow stunting disorder virus (CYSDV), and 22 showed a mixed infection with both WmCSV and CYSDV. No other cucurbit viruses were detected in any of the samples. Host range experiments revealed that eight out of fourteen tested plant species were susceptible to WmCSV. PCR products of approximately 1.2 kb were obtained after amplification using primers specifically targeting the coat protein region of WmCSV. Positive PCR results were confirmed by dot blot hybridization. Coat protein gene sequences from eleven WmCSV isolates indicated that the highest identity was between the 104WMA-SA isolate from the Wadi Baish location and a previously reported isolate from the AL-Lith location in Saudi Arabia. The lowest identity was observed between the 42WMA-SA isolate and an isolate from Palestine.

• Research in Plant Disease
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• v.13 no.2
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• pp.82-87
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• 2007

The genetic diagnostic method of virion capture (VC)/RT-PCR was developed for the simultaneous detection of three rod shaped viruses of Cucumber green mottle mosaic virus (CGMMV), Kyuri green mottle mosaic virus(KGMMV) and Zucchini green mottle mosaic virus (ZGMMV) transmitted by seed in Cucurbit. Out of 12 primer combinations for the three tobamoviruses, a primer set of CGMMV-C724, KGMMV-K513 and ZGMMV-Z407A was useful for mono and triplex VC/RT-PCR. The triplex VC/RT-PCR for the three tobamovirus in Cucurbit could detect specifically without interference among primers and/or plant species of watermelon, gourd, cucumber, melon, pumpkin, squash and Nicotiana benthamiana.

• The Plant Pathology Journal
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• v.31 no.4
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• pp.433-437
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• 2015

The infectious full-length cDNA clones of Cucumber green mottle mosaic virus (CGMMV) isolates KW and KOM, which were isolated from watermelon and oriental melon, respectively, were constructed under the control of the cauliflower mosaic virus 35S promoter. We successfully inoculated Nicotiana benthamiana with the cloned CGMMV isolates KW and KOM by Agrobacterium-mediated infiltration. Virulence and symptomatic characteristics of the cloned CGMMV isolates KW and KOM were tested on several indicator plants. No obvious differences between two cloned isolates in disease development were observed on the tested indicator plants. We also determined full genome sequences of the cloned CGMMV isolates KW and KOM. Sequence comparison revealed that only four amino acids (at positions 228, 699, 1212, and 1238 of the replicase protein region) differ between the cloned isolates KW and KOM. A previous study reported that the isolate KOM could not infect Chenopodium amaranticolor, but the cloned KOM induced chlorotic spots on the inoculated leaves. When compared with the previously reported sequence of the original KOM isolate, the cloned KOM contained one amino acid mutation (Ala to Thr) at position 228 of the replicase protein, suggesting that this mutation might be responsible for induction of chlorotic spots on the inoculated leaves of C. amaranticolor.

• Research in Plant Disease
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• v.15 no.1
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• pp.1-7
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• 2009

Viruses diagnosed on crops including rice plants from farmers or agricultural extension agencies cover the country were 11 species including Broad bean wilt virus 2 (BBWV2) in 2008. Tomato spotted wilt virus (TSWV) was the most important virus having the detection rate of 22.9%. Two viruses of Tomato yellow leaf curl virus (TYLCV) and Tobacco leaf curl virus (TLCV) inducing leaf yellow and curl diseases on tomatoes were occurred newly with the detection rate of 12.2% and 4.0%, respectively, in 2008. Rice stripe virus (RSV) was occurred on 869.5 ha mainly at Jindo and Haenam areas in Jeollanamdo province. At Jindo area, 12 plots were damaged severely with the infected hill rate of 83.8%. At the main production area of oriental melon at Seongju, almost all fruits from whole sale market at Seongju were infected with Cucumber green mottle mosaic virus (CGMMV) as the detection rate of 87%. The areas occurred TSWV in Korea were 25 totally from 2003 including 7 areas newly reported in 2008 including Naju in Jeoallanamdo. TSWV could be reduced as 0.1 % from 5.3% by covering insect proof net in vinyl house after chemical soil sterilization. Tomato yellow leaf curl disease was occurred on April in 2008 at Tongyoung area in Kyeongsangnamdo, and detected continuously at 13 areas, 7 in Kyeongsangnamdo, 4 in Jeollabukdo and 2 in Jejudo. Potato spindle tuber viroid (PSTVd) was occurred abruptly in a confined space of a civil breeding greenhouse and a cultivar evaluation field followed by disuse 17.4 M/T of potato tubers. No PSTVd was detected at 17 fields cultivated the related potatoes to the bred company by RT-PCR.