• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.2
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• pp.6-14
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• 1980

One of the physiological disease, sudden wiliting of Yushin variety suggested that low sunlight, excessive nitrogen application, and highly reduced soil condions either singly or combined, might be possible causes of the disorder. Some visual symptom of sudden wilting are discoloration of leaves, development of nodal roots above the soil surface, total root rot, and lodging. Those observations led to the hypothesis that suffocation of root tissues was a direct cause of the wilting. The oxygen transport characteristics of Yushin, IR262 and Tongil were examined by two methods. First, Soil-cultured plants of the three varieties were subjected to paraffin treatment to decrease the oxygen supply from the air to root tissues through the soil-water system, liquid paraffin was applied to the water surface in the pots at panicle formation stage. In this experiment, sudden wilting was observed of Yushin and IR262 at about a week after the treatment, but Tongil remained green and healthy. Wilting-resistant variety Tongil had higher oxygen release, whereas the susceptible Yushin and IR262 had lower oxygen release. Second, the number and size of the air spaces in each internode were investigated in the 5th internode from the top, all three varieties have a similar number of air spaces, although the air spaces of Thongil were larger. In the 4th internode, Tongil had plenty air spaces, Yushin and one of the Yushin's parents IR262 had scanty or none. The observations indicated that the ability of Yushin and IR262 for oxygen transport is very limited compared with that of Tongil. The limited oxygen supply due to poor development of air space in internode of rice plants may cause suffocation of root tissues, weaken metabolic activity of the tissues, and induce root rot, subsequently inducing sudden wilting and lodging under unfavorable weather, soil and cultural conditions.

• Korean Journal of Medicinal Crop Science
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• v.4 no.1
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• pp.68-73
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• 1996

Stem length, main root length and main root diameter showed rapid increasement in two-years-old and three-years-old peony. And there after, the increasement was almost finished. Occurrence of disease was increasing every cultivated year, especially the development of leaf spot was most serious. In propagation by root dividing method, the radix yield (kg/10a) was increasing every cultivated year. However, the difference of radix yield at four and five-years-old peony were not significant. The radix yield of four-years-old peony was higher 26% than three-years-old one. As cultivated year goes by, content of paeoniflorin was increasing then the content was highest at four-years-old peony (4.06%). In 1995, the content, had no certain tendency, was highest at three-years-old peony (3.14%). At hot air drying, browing of peony radix was increasing every cultivated year. If we consider radix yield and color, three-years-old peony was proper object of harvesting.

• Research in Plant Disease
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• v.25 no.1
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• pp.22-28
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• 2019

This study researched the current occurrence status of viral diseases of solanaceous crops in the main production areas of Gangwon region, for four years from 2014 to 2018. From 2014 to 2018, in eight cities and counties including Chuncheon, CMV, BBWV2, PMMoV, TSWV, and PVY occurred in chilli peppers. In case of tomato, the research was performed in 2017 and 2018 while TSWV and TYLCV were verified in Chuncheon, Hoengseong, and Cheorwon. Especially, TYLCV occurred in Chuncheon region for the first time in 2017, which was verified in 2018. Lastly, the current occurrence status of viral diseases of bell peppers was researched in seven cities and counties like Gangneung, Hoengseong, and Cheorwon from 2015 to 2018. In the results, CMV, BBWV2, PMMoV, PepMoV, and TSWV were verified in bell peppers of Gangwon region. During the research period, there were no crops suspected or infected by BWYV, so that it is judged that there is no villiferous or infected aphid by this virus in Gangwon-do. Such results of this study could be used as the basic data for the stable production of crops through the early prevention of plant diseases occurring in the solanaceous crops of Gangwon region.

• Research in Plant Disease
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• v.26 no.4
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• pp.272-278
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• 2020

The severe lettuce damage caused by Paratylenchus projectus was first reported in 2019 in Korea. To find high-value rotation crops for the control of P. projectus, nine vegetables, Brassica juncea (leaf mustard), B. rapa subsp. nipposinica (kyona), B. oleracea var. italica (broccoli), B. rapa subsp. chinensis (bok choy), B. oleracea var. viridis (kale), B. oleracea var. gongylodes (kohlrabi), Cichorium endivia (endive), C. intybus (chicory), Ipomoea aquatica (morning glory) were planted in d-10-cm clay pots in greenhouse. The growth of vegetables was compared between inoculated with 3,000 P. projectus per 100 ㎤ of soil and non-inoculated. Treatments were replicated 10 times. After 100 days, the reduction of fresh top weight was 30.4% in C. intybus, 35.1% in I. aquatica, 36.9% in B. oleracea var. acephala, 40.5% in C. endivia, 42.1% in B. rapa, 47.5% in B. rapa subsp. nipposinica, 50.4% in B. oleracea var. gonglodes, 56.3% in B. oleracea var. italica, and 66.0% in B. juncea. Nematode multiplication rates (Pf/Pi) were lower in I. aquatica (0.64) and C. endivia (1.1), but higher in B. oleracea var. gongylodes (2.54). Considering these results, I. aquatica is suitable for the rotation crop with lettuce until better rotation crops developed.

• Research in Plant Disease
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• v.29 no.4
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• pp.384-389
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• 2023

Milling can affect the distribution of mycotoxins in small grains. To investigate the effects on barley, seven hulled barley and three naked barley samples naturally contaminated with trichothecenes and zearalenone were obtained and milled at commonly used rates. Both barleys were simultaneously contaminated with deoxynivalenol and its acetyl derivatives (98.1-2,197.8 ㎍/kg), nivalenol and its acetyl derivative (468.5-3,965.1 ㎍/kg), and zearalenone (4.1-274.2 ㎍/kg). Milling hulled barleys at a rate of 67% reduced the mycotoxins in the grain by 90.9% for deoxynivalenol, 87.7% for nivalenol, and 93.2% for zearalenone. The reduction in naked barleys (milled at a rate of 70%) was slightly lower than in hulled barleys, with 88.6% for deoxynivalenol, 80.2% for nivalenol, and 70.1% for zearalenone. In both barleys, the acetyl derivatives of deoxynivalenol and nivalenol were reduced by 100%. However, barley bran had significantly higher mycotoxin concentrations than the pre-milled grains: bran from hulled barley had a 357% increase in deoxynivalenol, 252% increase in nivalenol, and 169% increase in zearalenone. Similarly, bran from naked barley had a 337% increase in deoxynivalenol, 239% increase in nivalenol, and 554% increase in zearalenone. These results show that mycotoxins present in the outer layers of barley grain can be effectively removed through the milling process. As milling redistributes mycotoxins from the grain into the bran, however, it shows that advance monitoring of barley bran is recommended when using barley bran for human or animal consumption.

• Research in Plant Disease
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• v.25 no.4
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• pp.157-163
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• 2019

This study aimed to assess the incidence and distribution of toxigenic fungi in Korean oat. Toxigenic fungi were isolated from oat samples collected from 12 oat fields from heading to harvest in 2017 and 2018. A total of 745 fungal colonies were isolated based on morphology and identified using marker genes. About 92% of the fungal isolates were Fusarium spp. and others were Penicillium (5.9%) and Aspergillus (2.1%). Fusarium isolates comprised mostly of F. asiaticum (83.1%), followed by F. incarnatum (5.4%), F. proliferatum (3.5%), F. fujikuroi (2.8%), F. tricinctum species complex (FTSC) 11 (1.5%) and F. graminearum (1.0%). About 97% of F. asiaticum was nivalenol type, and 3-acetyl deoxynivalenol (3.2%) and 15-acetyl deoxynivalenol (0.4%) types also were found. Pathogenicity test of the selected Fusarium isolates revealed that F. asiaticum isolates have a wide range of virulence depending on the tested plants. F. graminearum and FTSC 11 isolates from blighted spikelets were the most virulent in naked oat. All Fusarium isolates (n=18) except one (FTSC 11) produced nivalenol (0.2-7.6 ㎍/g), deoxynivalenol (0.03-6.1 ㎍/g), and zearalenone (0.1-27.0 ㎍/g) on rice medium. This study is first report that F. asiaticum causes Fusarium head blight disease of oat in Korea. These findings demonstrate the dominance of F. asiaticum in oat agroecosystems as in rice, wheat and barley in Korea.

• Journal of Sericultural and Entomological Science
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• v.53 no.1
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• pp.19-28
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• 2015

Though mulberry fruit is known to a by-product that was produced from mulberry tree after harvesting leaves for silkworm rearing, as a yield and consumption of mulberry fruit was increased, it has been fixing to a new income crop. But, a stable production of mulberry was issued on damage by the weather disaster, so it is requires that agricultural disaster insurance import. So, in this study as a basic research for a importation of agricultural disaster insurance, the cultivation of mulberry for the production of mulberry fruits, the shape of tree, the number of a bearing fruit from each cultivar, the occurrence of mulberry fruit sclerotic disease, and a yield and the market price of mulberry fruits were investigated and that results obtained were as follows; The number of mulberry tree each 10a was abundant in Buan and Jeongeup region that cultivated a suitable cultivar on low cut shape, however, a large cultivated Gochang region was little. The number of a bearing fruit per 1m on the branch was highest in the variety of Cheongilppong at Gochang. Yield of mulberry fruits each 10a was Cheongilppong at Gochang, followed by Iksuppong at Sangju. Average sale price of the mulberry fruits was high in the order of Gwasang No. 2, Suwonppong, Iksuppong, and Cheongilppong.

• Research in Plant Disease
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• v.20 no.4
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• pp.235-244
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• 2014

Clubroot and Fusarium wilt of cole crops (Brassica oleracea L.) are destructive diseases which for many years has brought a decline in quality and large losses in yields all over the world. The breeding of resistant cultivars is an effective approach to reduce the use of chemical fungicides and minimize crop losses. This study was conducted to evaluate the resistance of 60 cabbage (B. oleracea var. capitata) and 6 broccoli (B. oleracea var. italica) lines provided by The RDA-Genebank Information Center to clubroot and Fusarium wilt. To investigate resistance to clubroot, seedlings of the genetic resources were inoculated with Plasmodiophora brassicae by drenching the roots with a mixed spore suspension (1 : 1) of two isolates. Of the tested genetic resources, four cabbage lines were moderately resistant and 'K166220' represented the highest resistance to P. brassicae. The others were susceptible to clubroot. On the other hand, to select resistant plants to Fusarium wilt, the genetic resources were inoculated with Fusarium oxysporum f. sp. conglutinans by dipping the roots in spore suspension of the fungus. Among them, 17 cabbage and 5 broccoli lines were resistant, 16 cabbage lines were moderately resistant, and the others were susceptible to Fusarium wilt. Especially, three cabbage ('IT227115', 'K161791', 'K173350') and two broccoli ('IT227100', 'IT227099') lines were highly resistant to the fungus. We suggest that the resistant genetic resources can be used as a basic material for resistant B. oleracea breeding system against clubroot and Fusarium wilt.

• Korean Journal of Agricultural and Forest Meteorology
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• v.3 no.4
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• pp.199-205
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• 2001

This study was conducted to figure out temperature profiles of a partially developed paddy rice canopy, which are necessary to run plant disease forecasting models. Air temperature over and within the developing rice canopy was monitored from one month after transplanting (June 29) to just before heading (August 24) in 1999 and 2001. During the study period, the temporal march of the within-canopy profile was analyzed and an empirical formula was developed for simulating the profile. A partially developed rice canopy temperature seemed to be controlled mainly by the ambient temperature above the canopy and the water temperature beneath the canopy, and to some extent by the solar altitude, resulting in alternating isothermal and inversion structures. On sunny days, air temperature at the height of maximum leafages was increased at the same rate as the ambient temperature above the canopy after sunrise. Below the height, the temperature increase was delayed until the solar noon. Air temperature near the water surface varied much less than those of the outer- and the upper-canopy, which kept increasing by the time of daily maximum temperature observed at the nearby synoptic station. After sunset, cooling rate is much less at the lower canopy, resulting in an isothermal profile at around the midnight. A fairly consistent drop in temperature at rice paddies compared with the nearby synoptic weather stations across geographic areas and time of day was found. According to this result, a cooling by 0.6 to 1.2$^{\circ}C$ is expected over paddy rice fields compared with the officially reported temperature during the summer months. An empirical equation for simulating the temperature profile was formulated from the field observations. Given the temperature estimates at 150 cm above the canopy and the maximum deviation at the lowest layer, air temperature at any height within the canopy can be predicted by this equation. As an application, temperature surfaces at several heights within rice fields were produced over the southwestern plains in Korea at a 1 km by 1km grid spacing, where rice paddies were identified by a satellite image analysis. The outer canopy temperature was prepared by a lapse rate corrected spatial interpolation of the synoptic temperature observations combined with the hourly cooling rate over the rice paddies.

• The Korean Journal of Pesticide Science
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• v.5 no.2
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• pp.37-44
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• 2001

The biological effects of the iminoctadine tris (albesilate) and kresoxim-methyl for the protection of citrus postharvest diseases caused by penicillium spp. were assayed. In vitro tests, $EC_{50}$ values of iminoctadine tris(albesilate) were $0.01{\sim}0.02\;and\;0.01{\mu}g$ a.i./mL against mycelial growth of P. italicum and P. digitatum, respectively, but iminoctadine tris(albesilate) at $0.64{\mu}g$ a.i. /mL inhibited a little mycelial growth of unknown Penicillium sp. which produced another symptom different to blue and green mold caused by P. italicum and P. digitatum, respectively. And against germination and growth of germ tube of P. italicum and P. digitatum, $EC_{50}$ value of iminoctadine tris(albesilate) was $0.0013{\sim}0.0025{\mu}g$ a.i./mL. But spore germination of unknown Penicillium spp. was not nearly inhibited at $0.2{\mu}g$ a.i./mL. $EC_{50}$ values of kresoxim-methyl were $0.08{\sim}0.16$, 0.04 and $0.16{\mu}g$ a.i./mL against mycelial growth of P. italicum, P. digitatum and unknown Penicillium sp., respectively, and $0.04{\sim}0.08{\mu}g$ a.i./mL and $0.01{\sim}0.02{\mu}g$ a.i./mL against germination and growth of germ tube of P. italicum and unknown Penicillium sp., and P. digitatum, respectively. Iminoctadine tris(albesilate) and kresoxim-methyl were markedly effective to control the postharvest disease by 7 days spray prior to harvest. When the fruits were sprayed with iminoctadine-tris(albesilate) ($200{\mu}g$ a.i./mL) and kresoxim-methyl ($155{\mu}g$ a.i./mL) 7 days prior to harvest and subsequently stored for 90 days, the percentage of diseased fruit by Penicillium spp. was $3.6{\pm}1.8%$ in treatment of kresoxim-methyl and $5.9{\pm}1.8%$ in iminoctadine-tris(albesilate), respectively. On the other hand, tile percentage of diseased fruit was relatively high, $20.3{\pm}10.0%\;and\;19.5{\pm}9.6%$ in thiophanate-methyl ($700{\mu}g$ a.i./mL) and non-treatment, respectively. Maximum residue amount (ppm) among fruits (flesh and peel) assayed 0, 30, 60 and 90 days after storage was 0.45 and 0.10 ppm in treatment of kresoxim-methyl and iminoctadine, respectively.