• Research in Plant Disease
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• v.17 no.2
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• pp.228-231
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• 2011

Since 2008, a new leaf spot disease has been found in loquat tree (Eriobotrya japonica) at a nursery station in Goheung, Korea. Above 50% of the seedlings developed the spot symptoms on the leaves. The infected plants were generally reduced in the seedling vigour and early defoliation was occurred. The infected leaves developed grayish lesion with dark reddish brown margin. The pathogen developed round to ellipsoidal acervuli on the lesion. Based on morphological characteristics of the pathogen, the fungus was identified as Entomosporium mespili. The cultured pathogen successfully reproduced the same disease symptom on the leaves of loquat tree and found to be E. mespili. A monoconidial culture was deposited in Korean Agricultural Culture Collection (KACC 44727). This is the first report of E. mespili causing leaf spot of loquat tree in Korea.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.5
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• pp.40-50
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• 2007

One-year-old rooted cuttings of ten poplar clones and one willow clone were planted in a riparian area in Osan. Survival rate, growth performance, biomass, vitality, defoliation, leaf damages by diseases and/or insects and stem borer damage of the poplar and willow clones have been investigated for three growing seasons. Average survival rate of all eleven clones was declined from 80.7% for the first year to 60.7% for the third year. At three years after planting, poplar clones Dorskamp, ST-148 and Eco-28 showed the best survival rate of 80%. For height and DBH growth, the poplar clone Ay-48 and the willow clone 131-25 were the highest 8.3m and 9.5cm, respectively. However, poplar clones 72-30 and 72-31 were lower than those of the other clones. Clones Ay-48 and 131-25 seemed to have strong vitality when compare to the other clones. No serious damages by diseases and insects were found in most clones. Clones Ay-48 and ST-148 were the most tolerant to various diseases and insects. Clone Ay-48 produced the largest biomass for individual and annual total biomass, 22.5kg and 18.7ton $ha^{-1}$, respectively. Clone Dorskamp showed the best adaptability, which was estimated with survival rate, biomass and damages by various diseases and insects in the riparian area and followed by clones Ay-48, 97-19 and Eco-28. As a consequence, the four clones seemed to be the best candidate poplar clones for the establishment of riparian woody buffer.

• 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.

• The Plant Pathology Journal
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• v.22 no.2
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• pp.119-124
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• 2006

Kudzu vine(Pueraria montana var. lobata) is an invasive climbing woody vine that envelops trees and shrubs, pressing physically and shutting out sunlight, which needs to be controlled. Kudzu vine pathogens were surveyed as a way to seek its biocontrol agents in 2002. Occurrence of a bacterial halo blight disease of kudzu vine was observed at several localities in Korea including Euiwang and Suwon in Gyeonggi Province, Daejon, and Gochang and Buan in Jeonbuk Province. Symptoms of brown to black spots with a surrounding yellowish halo appeared from June and lasted till the rainy season without much expansion, but accompanying often leaf blight and defoliation. Isolated bacteria were identified as Pseudomonas syringae pv. phaseolicola based on physiological and cultural characteristics, Biolog, fatty acid and 16S rDNA sequencing analyses. In artificial inoculation test, these bacteria produced the same halo spot symptoms on kudzu vine and bean plants. They also induced hypersensitive responses (HR) on tobacco, tomato, and chili pepper leaves. This is the first report of a bacterial disease of kudzu vine in Korea, and the bacterial pathogen can be used as a biocontrol agent against the pest plant.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.9
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• pp.1253-1259
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• 2001

Three cassava varieties, namely MM 92 (MM), Black Twig (BT) and Local (LC), were arranged in a randomized complete block design to evaluate their dry fodder and crude protein (CP) productivity as well as growth persistency. Cassava plants grown in small plots of $5m{\times}10m$ at a planting distance of $25cm{\times}25cm$ were harvested every 6 weeks starting from 3 months after planting. Dry fodder yields of MM, BT and LC over the 8 harvests were 8.55, 8.01 and 6.15 t/ha, respectively. All varieties produced more leaves than stems with average leaf:stem ratios of 5, 5.9 and 4.8 for MM, BT and LC, respectively. In terms of CP production, MM was the highest yielder (272 kg/ha/harvest), followed by BT and LC (238 and 184 kg/ha/harvest, respectively). The total accumulative CP amounts over the 8 harvests were 2179, 1903 and 1474 kg/ha for MM, BT and LC, respectively. The mortality rates were 9.91, 14.01 and 13.98% for MM, BT and LC, respectively. Phosphorus content was more stable than potassium content during defoliation. MM, BT and LC had whole plant phosphorus contents of 0.41, 0.41 and 0.39%, respectively; whole plant potassium contents were 1.25, 1.38 and 1.20%.

• The Korean Journal of Mycology
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• v.48 no.1
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• pp.69-74
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• 2020

In September 2017, a heavy damage by premature defoliation with the zonate leaf spots was observed in several shrubs of Lespedeza cyrtobotrya growing at Mt. Obongsan in Chuncheon, Korea. Numerous cone-shaped, white sporophores of a fungus were observed on lesions of the abaxial leaf surface. A similar fungus was isolated in September 2019 from the leaves of L. cyrtobotrya growing at Mt. Taegisan in Hoengseong, Korea. The morphological characteristics of the sporophores were consistent with those of Grovesinia moricola. The species identification was confirmed by sequencing the internal transcribed spacer (ITS) region of the ribosomal DNA from the two isolates (KACC48417 and KACC48934). The fungal pathogenicity was determined by an artificial inoculation in conditions of relative humidity and temperature of 100% and 15±2℃, respectively. This is the first report of association of G. moricola with L. cyrtobotrya in Korea.

• Journal of Crop Science and Biotechnology
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• v.10 no.3
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• pp.147-158
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• 2007

Xanthomonas axonopodis pv. glycines(Xag) is a pathogen that causes bacterial leaf pustule(BLP) disease in soybeans grown in Korea and the southern United States. Typical and early symptoms of the disease are small, yellow to brown lesions with raised pustules that develop into large necrotic lesions leading to a substantial loss in yield due to premature defoliation. After Xag infects PI 96188, only pustules without chlorotic haloes were observed, indicating the different response to Xag. To identify differentially expressed genes prior to and 24 hr after Xag inoculation to PI 96188 and BLP-resistant SS2-2, an oligonucleotide macroarray was constructed with 100 genes related to disease resistance and metabolism from soybean and Arabidopsis. After cDNAs from each genotype were applied on the oligonucleotide macroarrays with three replicates and dye swapping, 36 and 81 genes were expressed as significantly different between 0 hr and 24 hr in PI 96188 and SS2-2, respectively. Six UniGenes, such as the leucine-rich repeat protein precursor or 14-3-3-like protein, were selected because they down-regulated in PI 96188 and up-regulated in SS2-2 after Xag infection, simultaneously. Using tubulin and cDNA of Jangyeobkong(BLP-susceptible) as controls, the oligonucleotide macroarray data concurred with quantitative real-time RT-PCR(QRT RT-PCR) results in most cases, supporting the accuracy of the oligonucleotide macroarray experiments. Also, QRT RT-PCR data suggested six candidate genes that might be involved in a necrotic response to Xag in PI 96188.

• Journal of Biosystems Engineering
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• v.41 no.3
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• pp.255-262
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• 2016

Purpose: Fuji apples are one of the top selling exports for South Korea bringing in over $233.4 million in 2013. However, during the last few decades, about half of the Fuji apple orchards have been infected by Apple Marssonina Blotch disease (AMB), a fungal disease caused by Diplocarpon mali., which takes about 40 days to exhibit obvious visible symptoms. Infected leaves turn yellow and begin growing brown lesions. AMB promotes early defoliation and reduces the quality and quantity of apples an infected tree can produce. Currently, there is no prediction model for AMB on the market. Methods: The Precision Agriculture Laboratory (PAL) at the University of Florida (UF) has been working with the National Academy of Agricultural Science, Rural Development Administration, South Korea to investigate the use of hyperspectral data in creating an early detection method for AMB. The RDA has been researching hyperspectral techniques for disease detection at their Apple Research Station in Gunwi since 2012 and disseminates its findings to the local farmers. These farmers were surveyed to assess the state of knowledge of AMB in the area. Out of a population of about 750 growers, 111 surveys were completed (confidence interval of +/- 8.59%, confidence level of 95%, p-value of 0.05). Results: The survey revealed 32% of the farmers did not know what AMB was, but 45% of farmers have had their orchards infected by AMB. Twenty-five percent could not distinguish AMB from other symptoms. Overwhelmingly, 80% of farmers strongly believed an early detection method for AMB was necessary. Conclusions: The results of the survey will help to evaluate the outreach programs of the RDA so they can more effectively educate farmers on the identifying, treating, and mediating AMB.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.408-412
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• 1998

In order to illustrate the role of conidia of Mycosphaerella nawae as a secondary inoculum in nature, pseudothecial development on persimmon leaves was investigated microscopically. The fungal ascospores have been believed as the primary or only inoculum source in nature, however, pseudothecia were readily formed on persimmon leaves infected naturally and artificially by conidia. The pseudothecia of M. nawae were found to form in the tissues of infected leaves while the leaves were still hanging on the trees. The size of pseudothecia were approximately 51.0~122.4$\times$51.0~112.2 ${\mu}{\textrm}{m}$ (82.8 $\times$72.5 ${\mu}{\textrm}{m}$in average), the shapes were spherical, ovoid or occidental pear type. The sizes of asci were approximately 30.6~61.2$\times$8.2~10.2 ${\mu}{\textrm}{m}$(46.6$\times$9.4 ${\mu}{\textrm}{m}$ in average) and the shapes were cylinder or banana. The ascospores were mostly spindle type, and the sizes were 10.2~12.2$\times$3.1~4.1 ${\mu}{\textrm}{m}$ (11.4$\times$3.2 ${\mu}{\textrm}{m}$ in average)-like. The pseudothecial formation was initiated before defoliation and morphological characteristics of the pseudothecia, ascus and ascospores on the infected leaves were fully illustrated in this study. Results indicated that conidia of M. nawae induce circular leaf spot of persimmon as much as ascospores, and might play an important role of the disease epidemics in nature.

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.2
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• pp.89-96
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• 2001

Carbohydrate and soluble protein reserves and regrowth characteristics in response to cutting height were investigated over four regrowth cycles of turf-type perennial ryegrass(Lolium perenne L. cv. preludeII). When the plants were at the full-vegetative stage (twelve weeks-old), three sequential defoliations at 3, 6 and 9 cm above the root base were imposed at 2-week intervals. Shoot dry weight in all three treatments continuously decreased with progressing regrowth cycle and the decreasing rate was higher as cutting height was lowered. TNC (total non-structural carbohydrate) in stubble at the end of the fourth regrowth cycle in 3, 6 and 9 cm cutting height decreased by 98%, 82% and 27%, respectively, comparing the initial content. TNC in roots also largely decreased with similar pattern in response to cutting height, whereas the absolute amount was much less compared to stubble. Soluble protein in stubble in 3, 6 and 9 cm cutting height decreased by 98%, 82% and 57%, respectively, at the end of fourth regrowth. A significant correlations between TNC (r=0.906) or protein (r=0.879) at the fourth defoliation and dry weight of regrowing shoots at the end of fourth regrowth were observed. these results indicated that cutting height closely influences the levels of organic reserves available for new growth, and that the levels of reserves might provide a useful tool as a determinant for regrowth dynamics.