• Weed & Turfgrass Science
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• v.3 no.4
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• pp.378-381
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• 2014

A new pathogen was isolated from zoysiagrass-planted park of Jeju island in 2014. Symptoms appeared a type of irregular patches occurring brownish leaf blight, followed by stem and crown rot. The symptom was very similar to that of large patch caused by Rhizoctonia solani, a well-known devastating zoysiagrass disease. The isolate showed thin orange-colored mycelia and screlotia were formed on the medium based on cultural characteristics. The causal agent of the disease was finally identified as Waitea circinata by analysis of ribosomal DNA. On the inoculation test, Waitea circinatae showed strong pathogenicity to the zoysiagrass. The mycelia were obviously observed in the inoculated tissues. This is the first report of Waitea ring patch caused by Waitea circinata on zoysiagrass.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.4
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• pp.382-390
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• 1999

In order to identify the responses of Korean soybean cultivars to sudden death syndrome (SDS), forty-two Korean cultivars and three check cultivars (Hartwig and PI 520733 are resistant; Hartz 6686 is susceptible) were tested with sorghum seed inoculum infested with Fusarium solani f. sp. glycines isolate 171 in the greenhouse. This isolate has blue pigment cultural shape on potato dextrose agar (PDA) medium. All Korean cultivars inoculated with F. solani isolate 171 showed the typical SDS symptoms and disease severity on soybean leaves in each cultivar varied at 4 weeks after inoculation. Nine cultivars were included in the most SDS susceptible group and six cultivars were included in the most susceptible group based on Duncan＇s multiple range tests (P$\leq$0.05). In results of the LSD analysis for SDS the resistant group, a total of twenty-five Korean cultivars were included in the same SDS resistant group as PI 520733 or Hartwig and fourteen Korean cultivars were included in the same SDS susceptible group as Hartz 6686. In the second experiment, ten Korean cultivars, ten U.S. cultivars, and one introduced line were compared in the same way as the first experiment Disease severity ranking of check cultivars, Hartwig, PI 520733, and Hartz 6686, were the same as in the first experiment. Within Korean cultivars, seven cultivars showed the consistent severity proportions of leaf symptoms. Disease rankings of these cultivars in this experiment were the same as those in the first experiment. Three US cultivars: Hartwig, Hartz 5454, and Forrest, three Korean cultivars： Keunolkong, Myeongjunamulkong, and Jinpumkong 2, and one introduced line, PI 520733, were included in the highest SDS resistant group. Shinphaldalkong 2, Milyang 87, and Samnamkong consistently showed the highest SDS susceptibility in both experiments. Average disease severity in the first and the second experiment were 49.56% and 45.39%, respectively.

• The Plant Pathology Journal
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• v.30 no.4
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• pp.355-366
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• 2014

In this study, resistance responses were investigated during the interaction of Botrytis fabae with two faba bean cultivars expressing different levels of resistance against this pathogen, Nubaria (resistant) and Giza 40 (susceptible). Disease severity was assessed on leaves using a rating scale from 1 to 9. Accumulation levels of reactive oxygen species (ROS), lipid peroxidation and antioxidant enzymes (superoxide dismutase, catalase and ascorbate peroxidase) were measured in leaf tissues at different times of infection. The expression profiles of two pathogenesis-related proteins (PRPs) encoded by the genes PR-1 and ${\beta}$-1,3-glucanase were also investigated using reverse transcription RT-PCR analysis. The accumulation of these defense responses was induced significantly in both cultivars upon infection with B. fabae compared with un-inoculated controls. The resistant cultivar showed weaker necrotic symptom expression, less ROS accumulation, a lower rate of lipid peroxidation and higher activity of the enzymatic ROS scavenging system compared with susceptible cultivar. Interestingly, ROS accumulated rapidly in the resistant leaf tissues and peaked during the early stages of infection, whereas accumulation was stronger and more intense in the susceptible tissues in later stages. Moreover, the response of the resistant cultivar to infection was earlier and stronger, exhibiting high transcript accumulation of the PR genes. These results indicated that the induction of oxidant/antioxidant responses and the accumulation of PRPs are part of the faba bean defense mechanism against the necrotrophic fungus B. fabae with a different intensity and timing of induction, depending on the resistance levels.

• Korean Journal of Environmental Agriculture
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• v.23 no.3
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• pp.128-132
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• 2004

Ozone effects were studied by plant growth chamber to evaluate the impact of ozone ($O_3$) on the physiology of two hot pepper, Capsicum annuum L., cultivars, 'Dabotab' and 'Buchon'. Forty-day old plants with $5{\sim}7$ leaves were exposed to $O_3$ of <20 and 150 nL/L for 8h/d for 3 days. Net photosynthesis and stomatal conductance were measured and foliar injury was described. Foliar damage due to the treated $O_3$ was different from the varieties. 'Dabotab' was most sensitive to $O_3$ and 'Buchon' was resistant. Symptom of ozone damage on the leaves was bifacial necrosis. Decreases of net photosynthesis by $O_3$ were 56% and 40% on 'Dabotab' and 'Buchon', respectively. Decreases of stomatal conductance by $O_3$ were 66% and 63% on each variety. $O_3$ damage on net photosynthesis was started at the low levels of light on the two hot peppers. In addition, assimilation-internal $CO_2$ concentration curves were not different from the two varieties. In conclusion, $O_3$ closed the stomata and decrease net photosynthesis on hot peppers regardless of the ozone sensitivity on leaf injury, but the difference of ecophysiological responses between the two varieties was not found clearly.

• Research in Plant Disease
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• v.10 no.2
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• pp.112-116
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• 2004

This study was carried out to investigate factors affecting disease development of rice brown spot caused by Cochliobolus miyabeanus in the field and under the greenhouse conditions. In normal paddy fields, the pathogen was more frequently isolated from dried rice straws than wet straws after overwintering. The pathogen was also readily isolated from wet rice straws of salty paddy fields although infection rate of the fields was low. The disease symptom was first observed at 2 to 3days after inoculation when the seedlings were kept for 6 hours in dew chamber. The number of lesions peaked at 14 hr incubation in cultivars Chucheongbyeo and 24 hr incubation in cultivar Daesanbyeo and Tetep. Sixty three-d-old seedlings were more susceptible than 21 to 49-d-old seedlings regardless of cultivar. There was some difference in number of lesions observed, but the lesions were evenly spread regardless of leaf position. Light on the rice seedlings at 3,000 lux or 6,000 lux showed more severe symptoms than those in the dark.

• The Plant Pathology Journal
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• v.20 no.2
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• pp.106-109
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• 2004

A leaf blight disease was found on Ailanthus altissiman growing in the Manchon Mountain Park in Daegu city. When isolated, the causal fungus readily formed sex organs, being homothallic. Oogonia were spherical, 19.5-42.9 ${\mu}{\textrm}{m}$ in diameter with an average of 29.4$\pm$4.2 ${\mu}{\textrm}{m}$. Antheridia were amphigynous, round to ovoid, and measured 11.3-15.0 ${\mu}{\textrm}{m}$ long and 12.5-14.5 ${\mu}{\textrm}{m}$ wide. Oospores in the oogonia were spherical, 26.1-29.0 ${\mu}{\textrm}{m}$ in diameter. Sporangia that formed in water were spherical to sub-spherical with a conspicuous papilla and measured 19.5-56.6 ${\times}$ 15.6-44.9 ${\mu}{\textrm}{m}$ with an average of 44.0$\pm$8.7${\times}$32.7$\pm$6.3 ${\mu}{\textrm}{m}$. The mean length/breadth (I/b) ratio was 1.35. Papillae were 3.9-11.7 ${\mu}{\textrm}{m}$l high and 3.9-9.8 ${\mu}{\textrm}{m}$ wide. Sporangia formed slowly on V8 juice agar medium when cultured under fluorescent light at 12-hour alternation. The sporangia that formed on the agar medium were more spherical and measured 26.5-39.0${\times}$23.4-35.1 ${\mu}{\textrm}{m}$ with an average of 33.6$\pm$3.4${\times}$28.2$\pm$3.2 ${\mu}{\textrm}{m}$ and I/b ratio of 1.19. Disease symptom was repro-duced by artificial inoculation of the healthy plants with the isolate. The causal organism was identified as Phyto-phthora boehmeriae on the basis of its morphological characteristics.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.2
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• pp.160-165
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• 1997

Three types of virus disease symptoms were observed in azuki bean plants: yellow mosaic; mosaic; severe mosaic with dwarf. The symptoms developed in the indicator plant inoculated with a virus- infected leaf of azuki bean showed similar host range with those of AMV, CMV and AzMV. In antiserum response, yellow mosaic symptom formed sediments with AMV antiserum, mosaic type with CMV antiserum, respectively, From the electron microscope observation, eclliptic particle (18~58$\times$18nm), isometric particle (30nm), and filamentous(730$\times$12nm) combined with inclusion body were observed in yellow mosaic, mosaic, and severe mosaic with leaf curling symptoms, respectively, The results demonstrate that yellow mosaic, mosaic, and severe mosaic with dwarf are caused by AMV, CMV and AzMV.

• The Plant Pathology Journal
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• v.36 no.3
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• pp.267-279
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• 2020

Fig mosaic is a viral disease (FMD) that spreads in Palestinian common fig (Ficus carica L.) orchards. Recognizing the economic value of fig plants and the harmful nature of FMD, the disease poses a significant threat to the economy of the fig production in Palestine. We applied the reverse transcription and amplification (RT-PCR) and PCR technique to leaf samples of 77 trees and 14 seedlings of 17 fig cultivars. The samples were collected from orchards in the main fig-growing provinces of the Palestinian West Bank, to assess the prevalence of viruses associated with FMD, and confirm a possible link of symptoms with viruses detected. Four viruses were detected: Fig mosaic virus (FMV), Fig badnavirus-1 (FBV-1), Fig leaf mottle-associated virus 2 (FLMaV-2), and Fig fleck-associated virus (FFkaV). FMV and FBV-1 were found in all tested fig plants (100%), while FLMaV-2 and FFkaV were detected in 61.5% and 33% of the fig samples, respectively. The high incidence of FBV-1 in the newly propagated symptomatic and symptomless seedlings from different cultivars may be an indication that FBV-1 is integrated into the genome of the fig in a cultivar nondiscriminatory manner. Very weak or no association was detected between FMD symptoms severity in the 17 Palestinian fig cultivars with the various viruses' combinations observed (i.e., number of the viruses infecting the plant). These results support the notion that FMD symptom severity expression is likely to be controlled by a combination of FMV infection, cultivars, and environmental factors, rather than the number of viruses infecting the plant.

• Weed & Turfgrass Science
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• v.1 no.4
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• pp.76-79
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• 2012

This study provides basic information on morphological characteristics of zoysia mite, Aceria zoysiae and symptom in zoysiagrass for turfgrass management in golf courses. Zoysiagrass mite distributed from Pocheon, Gyeonggii province to Jinju, Gyeongnam province and damaged turfgrasses from spring to fall. Damaged leaf by zoysiagrass mite was rolled unidirectionally and mite damaged leaves in the inside of rolled part. Leaves was turned to yellow and damaged area formed irregular yellow patch.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.377-384
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• 2009

Three-year-old seedlings of susceptible Pinus densiflora and resistant Pinus x rigitaeda were each inoculated with the pinewood nematode, Bursaphelenchus xylophilus, to compare disease development. Needle dehydration was evident on seedlings of P. densiflora by 20 days after inoculation, 10 days earlier than this symptom was observed on P. ${\times}$ rigitaeda. Xylem drying was more frequent in seedlings of P. densiflora than in that of P. ${\times}$ rigitaeda between 20 and 60 days after inoculation. No significant differences were found between P. densiflora and P. ${\times}$ rigitaeda for stem water content or for stem and leaf relative water content in current-year branches after nematode inoculation, but the average number of B. xylophilus recovered from stems differed significantly between the two groups. The number of B. xylophilus recovered from stems was negatively correlated with the stem water content and with stem and leaf relative water content. By the time the experiment was terminated at 60 days after inoculation, all 3 of the last group of P. densiflora seedlings had died, but 2 of the 3 remaining P. ${\times}$ rigitaeda hybrid seedlings were still alive. Additional studies are needed to further explore the specific mechanisms preventing nematode multiplication in the seedlings of resistant P. ${\times}$ rigitaeda.