• Korean Journal of Organic Agriculture
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• v.23 no.2
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• pp.347-357
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• 2015

This experiment was conducted to test the efficiency of environmentally friendly materials for controlling garlic leaf blight by Stemphylium botryosum. Fifty five kinds of environmental friendly control agents are obtained from commercial market and are tested for spore germination using 96 well plate and among them, five agents (copper-, sulfur-, medinal herb extract-, sulfur+sodium bicarbonate- and oligo chitosan based compound) are selected for field test from 2012 and 2013 year. With reference of 2012 year test result, copper and oligo chitosan based compounds are chosen as 2013 year test. When the first symptoms were appeared early May season and environmental friendly control agents are applied as prompt as possible, the control value of copper and oligo chitosan based agents are 54% and 90% respectively as compared to the occasion of chemical agent Antracol WP (propineb 70%) and yield of bulbs are increased by 16% and 34% against untreated control and marketable garlic bulb yield were 79% and 95% against Antracol WP treatment, respectively. From this result, oligo chitosan based compound can be a good organic control agent candidate for garlic leaf blight disease in organic garlic cultivation.

• Research in Plant Disease
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• v.17 no.3
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• pp.317-325
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• 2011

Bacterial pustule of soybean (Glycine max) caused by Xanthomonas axonopodis pv. glycines is one of the most prevalent bacterial diseases of soybean in Korea, where it causes considerable yield loss. This study was carried out to develop yield prediction model for bacterial pustule by analyzing correlation between the percentage of diseased leaf area and yield. The severe disease incidence of soybean bacterial pustule caused yield losses by 19.8% in 2006 and 16.8% in 2007, respectively. Severity of bacterial pustule greatly affected on 100 seed weight and yield, but did not on stem length, number of branches per plant, number of pods per plant, number of seeds per plant. On the other hand, correlation coefficients between diseased leaf area and yield were $-0.93^*$('06) and $-0.77^*$('07), respectively. The regression equation obtained by analyzing correlation between the percentage of diseased leaf area and yield loss in 2006 and in 2007 was y = -3.2914x + 348.19($R^2$ = 0.8603) and y = -2.9671x + 302.08($R^2$ = 0.9411), respectively. These results will be helpful in estimating losses on a field-scale and thereby predicting the production of soybean.

• Research in Plant Disease
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• v.23 no.3
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• pp.228-233
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• 2017

Six commercial rootstock varieties were tested for resistance to bacterial wilt (Ralstonia solanacearum) by dipping the roots of seedlings in the bacterial suspension at seedling stage. 'Shincheonggang' and 'B-Blocking' ranked top and second in resistance to bacterial wilt, respectively. For disease index of the grafted plants, 'Dotaerang' grafted onto 'Shincheonggang' was the least, followed by 'Ultra', 'Fighting', 'B-Blocking', 'Special', and 'Connection' grafts. Thus, disease development on the grafted plants was correlated with resistance of rootstocks. The effect of rootstocks on horticultural characteristics including days to flower of scion was minimum or negligible. In correlation between horticultural characteristics of rootstocks and scions grafted thereon, statistically significant negative correlation was observed in days to flower and fruit height but no significant correlation was observed in yield per plant, fruit diameter and soluble solid content in the fruits. Thus, selection of resistant rootstock varieties that support the growth and yield of scion well is necessary for effective control of the disease and yield increase.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.1
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• pp.55-60
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• 1987

Fifty eight isolates of R. solani collected from rice plants infected to sheath blight disease at seven different locations through the country were evaluated for their cultural characteristics on media. Degree of resistance of nine rice varieties were tested by the seven isolates representing each culture type from the grouped pathogene-city. Great variation of cultural characterisics on PSA media was observed among isolates, and 58 isolates tested were grouped into 7 culture types. Locational distribution of isolates belong to each culture type was different between types, and only isolate type 'Ia' was distributed in all locations collected. The degree of pathogene-city of each isolate to rice adult plant was different between 7 culture types grouped, and no isolates infected severely on all tester rice varieties. The degree of resistance to the disease showed great variation among 9 tester varieties, and varietal reaction to the disease was varied along with isolates inoculated. An isolate, la, shown strong pathogenecity and distributed through 7 locations was selected for the screening of varietal resistance to rice sheath blight disease.

• Research in Plant Disease
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• v.15 no.3
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• pp.198-201
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• 2009

Bacterial wilts, caused by Ralstonia solanacearum, is a very destructive disease to tomato plants (Solanum lycopersicum) in Korea. Selection of resistant cultivar is the best way to prevent or reduce the occurrence of this disease. Thirty-nine tomato cultivars, twenty-one cherry tomato cultivars and thirteen rootstock tomato cultivars were inoculated with Ralstonia solanacearum, to evaluate tomato cultivars for resistance against bacterial wilts. Thirty-seven cultivars were highly susceptible to bacterial wilts and 61-100% of their whole tissue became wilted within 10 days after inoculation. Twenty-four cultivars showed moderate resistance and twelve were resistant to bacterial wilts. In an evaluation of 73 major commercial cultivars, 'Lilyance', 'TP-7', 'Choice', 'Dadaki', 'Akiko', 'Redstar', 'Match', 'B-blocking', 'Magnet', 'Support', 'Friend' and 'Special' were found to have a high level of resistance to bacterial wilts of tomatoes.

• Journal of Plant Biotechnology
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• v.44 no.3
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• pp.325-329
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• 2017

A micropropagation method via callus for Ranunculus kazusensis Makino, an endangered species, was established. When stem segments were cultured on MS media supplemented with 1.0 mg/L IAA, NAA, IBA and 2,4-D, the highest frequency of callus induction was achieved on MS medium supplemented with 1.0 mg/L NAA. Multiple shoot per explant was obtained, the MS medium containing 1.0 mg/L BA and 0.5 mg/L NAA. Additionally, effect of activated charcoal (AC) and sucrose on shoot growth in in vitro culture were examined. The most suitable conditions for shoot growth after 4 weeks of culture were the MS medium with AC and sucrose. This in vitro propagation protocol will be valuable for conservation and mass propagation of this endangered plant.

• Research in Plant Disease
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• v.15 no.2
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• pp.63-67
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• 2009

Rice stripe virus (RSV) is one of Tenuivirus Group, which is carried by small brown planthopper. There is an outbreak of RSV in South Korea at 20Ot, and 2007. The infection caused by RSV had been investigated on weeds around the rice cultivated areas 13 region and 26 site including Jeonbuk Buan and Chungnam Seocheon. There have a doubt as to alternate host of RSV is total 15 Family and 50 Species including Gramineae 24 species of Duksaepul (Alopecurus aequalis), H. sativum var. vulgare etc.. There is identified the infected RSV in Festuca myuros, Alopecurus aequalis, Hordeum sativum var. vulgare, Trisetum bifidum, Echinochloa crus-galli var. crus-galli, Digitaria ciliaris among this species. Deulmuksae is the overwintering exotic weed which sprout in Autumn and wither in Spring and commonly growed as green manure crop or cover crop. In order to identify the infection rate furthermore, 111 samples which were collected at Buan Gyehwa-myeon region, and 50 samples from Seocheon Maseo-myeon in June, 2008, were ELISA tested. The results are 32 positives from Buan, 28.8% infection rate, 8 positives from Seocheon 16.0% infection rate. RSV infection of Deulmuksae is not reported currently, and follow report first describes the Deulmuksae as an alternate host of RSV.

• Korean Journal of Microbiology
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• v.46 no.3
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• pp.248-254
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• 2010

To define the optimum conditions for the mass production of four antifungal Pseudomonas spp. isolated from soil, we have investigated culture conditions and effects of various nutrient sources on the bacterial growth and evaluated antagonistic activity against Rhizoctonia solani and Sclerotinia homoeocarpa, plant pathogens. The optimum temperature and pH for the growth of these isolates were determined as pH 7.0 and $20^{\circ}$ or $25^{\circ}C$, respectively. Sucrose, tryptone, and $K_2HPO_4$ generally were more adequate for better growth as carbon, nitrogen and mineral source, respectively. The nutrient sources were also found to be very effective for high antifungal activities against R. solani and S. homoeocarpa. It was elucidated that YUD-F group (P. mandelii and P. fluorescens), which inhabit regions at relatively low temperature, had more broad spectrum and higher antifungal activity than YUD-O group (P. trivialis and P. jessenii) generally against R. solani and S. homoeocarpa. It is thought that the differences of the average temperature in the various habitats of Pseudomonas spp. influence the optimal growth temperature and antifungal activity. Especially, Pseudomonas spp. of YUD-O group showed the better antifungal activity against dollar spot caused by S. homoeocarpa, but showed relatively weaker antifungal activity against brown patch caused by R. solani.

• Korean Journal of Weed Science
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• v.17 no.4
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• pp.413-420
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• 1997

In this study, germination characteristics and effect of some chemicals on germination of Trapa japonica $F_{EROV}$ seeds were investigated to obtain a fundamental data for controlling them. When the seeds were stored at low temperature for at least 3 months, their dormancy was completely released with a germinability of above 90%. However, those stored under the room or high temperature condition were never germinated. Germination was best at constant temperature of around $25^{\circ}C$ or at alternate temperature of 25/$15^{\circ}C$ (12 hr-day/12 hr-night), and was nat dependent on light. They could germinate though planted at the depth of 15 cm, but their initial growth were: suppressed with increase of planting depth, especially above 10 cm depth. Germinability was lost when the fresh weight was decreased more than 30%, indicating that the seed is sensitive to dehydration. The freezing at $-20^{\circ}C$ for 1 hr didn't affect germination, but 5 hr treatment completely killed them. Their germination was inhibited by 100% at 100 ppm ABA and slightly inhibited above 25 ppm of butachlor, whereas pyrazosulfuron-ethylnt is likely to control T. japonica physically and herbicide treatment to inhibit germination may not be recommendatory. and bensulfuron-methyl didn't inhibit the germination at the concentration of 100 ppm. Taken together, dehydration treatme is likely to control T. japonica physically and herbicide treatment to inhibit germination may not be recommendatory.

• Korean journal of applied entomology
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• v.23 no.2 s.59
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• pp.96-101
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• 1984

This experiment was carried out to investigate control efficacy by cultural practice and fumigation of tacterial wilt caused by Pseudomonas solancearum in resistant tobacco line NC82 at the Korea Ginseng and Tobacco Research Institute, Eumseong Experiment Station in 1982 and 1983. The bacterial wilt of tobacco occurred severely from mid-July to last August in applicable temperature and soil humidity for increasing bacteria. Disease severity appeared low and slowly at fumigation and resistant variety treatment. Incidence of bacterial wilt in tobacco line NC82 was $44.7\~55.8\%$ being compared with susceptible variety, NC2326 and $95\~99\%$ when resistant variety, NC32 was cultivated with soil fumigation treatment. Control efficacy of cultural practices appeared low with $0.8\~20\%$ and was not different from resistant variety and fumigation treatment. Control system against bacterial wilt in flue-cured tobacco was accomplished by control efficacy over $95\%$ when resistant variety(NC82) was cultured after treatment of cultural practices (Tillering after harvest and before transplanting, stalk and root destruction, early transplanting early removal of the mulching film) and soil fumigation(Cylon).