• Research in Plant Disease
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• v.14 no.3
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• pp.193-200
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• 2008

Blending of eggshell powder into soil as ratio of 1:5, 1:10, 1:15, 1:20, and 1:25 did not affect seed germination rates of several crops including Chinese cabbage. The blending increased pH of distilled water and decreased the viability of resting spores of Plasmodiophora hrassicae. The ratio of non-viable resting spores in eggshell-blending water was over five times higher than in distilled water of the same pH. Chinese cabbage (cv. 'Norangbom') grew more in eggshell-blended soil than in non-treated soil, but other crops grew less. Leaf numbers and above ground growth of Norangbom increased to around 150% and 470%, respectively, in soil blended with $1:20{\sim}1:15$ of eggshell powder. Even though the optimum sizes of eggshell powder were $0.8{\sim}2.0mm$ for growth and smaller than 0.4 mm for inhibition of clubroot disease of Chinese cabbage, there was no statistical difference among the sizes. Soil pH was above 8.0 in all eggshell treatments without any statistical difference among them. Eggshell powder blending to 1:20 showed lower control efficacy, 58.5%, than registered fungicide 'Hokanna (flusulfamide)', 78.5%. However, Chinese cabbage of that blending ratio recorded the highest growth among the treatments. Therefore, blending of eggshell powder into clubroot-contaminated soil may make culture of Chinese cabbage possible by growth-increasing, even though eggshell powder could not inhibit clubroot disease entirely.

• Research in Plant Disease
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• v.15 no.2
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• pp.106-111
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• 2009

Before transplanting Chinese cabbage seedlings, two kinds of eggshell powder were blended into the soil of cabbage field where the club root pathogen, Plasmodiophora brassicae, was infested. The incidence of clubroot disease, the shoot and root growth of cabbages, and soil pH were examined four times at 10 to 13 days interval from transplanting Chinese cabbage. As results, the cabbages treated with eggshell powder without membrane showed the fastest growth in above ground part, and the lowest disease index for clubroot disease. The cabbages treated with eggshell powder with membrane showed better growth than the cabbages of non-treated check, but lower growth than those treated with eggshell powder without membrane. Soil pH started to increase from 3 weeks after soil blending of eggshell powder, and it reached to above 8.0. However, the soil pH of non-treated check stayed at around 6.8. In the experiment to compare the effect of eggshell powder with other calcium compounds, soil-blending of $CaCO_3$ resulted the lowest disease incidence of 1.7 and the registered fungicide, 'flusulfamide', and the resistant variety 'CR Green cabbage' followed with the incidence of 1.9. Cabbages of non-treated check scored the highest disease incidence, 3.4, and that of eggshell powder without membrane was as high as 2.7. However, the growth of Chinese cabbage showed the different pattern to the disease incidence. Chinese cabbages treated with eggshell without membrane recorded the highest average growth, around 2.1 kg. On the other hand, the average growth of CR Green Chinese cabbage was about 2.0 kg, that of flusulfamide-treatment plot was 1.7, and that of non-treated check was as low as 1.3 kg. Soil blending of eggshell powder without membrane did not inhibit the development of clubroot, but increased the growth of cabbage to a great extent. Therefore, it was confirmed that soil blending of eggshell powder before transplanting makes the Chinese cabbage culture possible even in the field infested with club root pathogen.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.2
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• pp.149-154
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• 1992

Buckwheat has been a popular favorite food crop in Korea for a long time. The objective of the study was to investigate the effects of climatic conditions and cultural methods on grain yields of summer buckwheat variety Sinnong 1 planted during the spring season in Suwon, Korea from 1989 to 1991. Frost minimum temperature of late April was -0.3$^{\circ}C$ in 1990 being very low as compared with 3.7$^{\circ}C$ of the normal year, and affected early growth of the seedlings emerging from the soil surface. In late May of 1990, the frost minimum temperature was 7.3$^{\circ}C$ being low as compared with 8.8$^{\circ}C$ of the normal year, and also induced cold injury to fertilization and grain filling. Total precipitation 374.5mm of mid and late June, 1990 provided serious damage to the grain filling and maturing buckwheat seeds and along with causing seed sprouting before harvest. However, the climates of 1989 and 1991 were very good for the growth and development of spring-sown buckwheats. When summer buckwheat cultivar Sinnong 1 was planted on April 20, 1989, its highest grain yields 268-292kg /10a were harvested from the plots of seeding rate 8kg /10a, drill seeding and polyethylene film mulching, and the mean grain yield of the plots was 238kg /10a in 1989, but 64.3kg in Suwon, and 40.2kg /10a in Muan in 1990. In 1991 maximum grain yield 277kg /10a was produced from the April 15 planted and vinyl-mulched plot, and 255kg /10a from the April 25 planted and non-mulched plot. Herbicide Alachlor-sprayed plots produced lower grain yields than no weed control and manual weeding plots. Mechanized drill-seeding saved 83～84% in planting hours as compared with manual broadcasting 21.6 hours /ha, and produced 9% more in grain yields from the two-season croppings of mechanized drill-seeding culture being 364kg /10a in total yields per year.

• Korean Journal of Environmental Agriculture
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• v.20 no.3
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• pp.180-185
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• 2001

Control effects of phosphorous acid were investigated on Phytophthora blight of red pepper plants in greenhouse and field. In vitro test, the mycelial growth of Phytophthora capsici was inhibited by the phosphorous acid more than 97% at 1,000 ${\mu}g$ and 10,000 ${\mu}g$ a.i./mL in the liquid and solid culture, respectively. At concentration of 10 ${\mu}g$ a.i./mL of phosphorous acid, in the liquid culture the mycelial growth of P. capsici was inhibited 46.2%, however inhibited only 4.9% on the soild culture. Zoosporangial formation was also inhibited 89.1% by phosphorous acid at 100 ${\mu}g$ a.i./mL. Phosphorous acid affected more zoosporangial formation of P. capsici than its mycelial growth. At the concentrations of 10,000, 1,000 and 100 ${\mu}g$ a.i./mL of phosphorous acid, germination of zoosporangia was inhibited 100, 84.3 and 44.2%, respectively. Mycelial growth and zoosporangial formation of P. capsici were little affected at the concentration of 10 ${\mu}g$ a.i./mL of phosphorous acid. Cermination of zoosporangia was also little affected at this concentration, however growth of the germ tubes was inhibited and the abnormal mycelial growth was observed. Phosphorous acid suppressed the incidence of Phytophthora blight of red pepper plants up to $77.0{\sim}62.0%$, in greenhouse. Phosphorous acid suppressed the incidence of Phytophthora blight of red pepper plants up to 54.0% at the conventional culture in field. Treatments of phosphorous acid increased up to 113% in height, 135% in number of fruit, and 129% in weight of fruit.

• Korean Journal of Weed Science
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• v.5 no.1
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• pp.63-72
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• 1985

To establish the method of integrated weed management in rice nurserybed, phytotoxic factors of herbicide and antidote efficacy were evaluated at the Yeongnam Crop Experiment Station in 1982 and 1984. Seven hundred eighty four research items were carried out as weed control research since 1961. While 65% of these were belonged to rice research, only 6% was attributed to nurserybed among rice research. More herbicidal phytotoxicity exhibited when seedbed was pressed just after seeding than sand covered or uncovered seedbed and also this phytotoxic symptom enhanced by using intact seed compared to pregerminated seed. Rinsing practice of seedbed reduced the phytotoxic effect of butachlor and this effect was more pronounced with the number of rinsing operation increase and at the pressed plot. However, herbicidal efficacy was not significantly decreased by rinsing operation. Growth of rice seedling hardly affected where the herbicide was absorbed through root only compared to absorption from both of root and shoot for pyrazolate, butachlor and thiobencarb. Herbicide antidote `CGA 123'407' completely protected from the phytotoxic effect of pretilachlor without arising any adversal effect in weed control. However, without antidote, pretilachlor showed the most severe phytotoxic symptom among used herbicides.

• Weed & Turfgrass Science
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• v.3 no.4
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• pp.262-268
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• 2014

This study was conducted to provide basic information for weed control by surveying the occurrence of weed species. Surveys of weed species occurred in food crop (barley, maize, potato, soybean) fields were conducted in Chungnam province from April to September in 2014. Total 321 sites of food crop fields in 17 City / Gun in Chungnam province were investigated. From the result of this survey, 130 weed species in 36 families were identified and classified to 77 annuals, 27 biennials and 26 perennials. Based on the occurrence ratio, the most dominant weed species in Chungnam province food crop fields were Digitaria ciliaris (10.19%), followed by Conyza canadensis (7.82%), Portulaca oleracea (5.22%), Chenopodium album var. centrorubrum (5.21%), Capsella bursa-pastoris (3.47%) and Alopecurus aequalis (3.47%). Forty-four exotic weed species were identified. This information could be useful for estimation of future weed occurrence, weed population dynamics and establishment of weed control methods in food crop fields of Chungnam province.

• Korean journal of applied entomology
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• v.42 no.3
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• pp.225-231
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• 2003

The susceptibility of the different larval stages of Spodoptera litura to nine insecticides was evaluated using the perilla leaf-dipping method. Median lethal concentration ($LC_{50}$) was increased with larval development in the range of 0.5 ppm to 5.6 ppm, 9.9 ppm to 27.9 ppm, 9.6 ppm to 125.1 ppm and 24.3 ppm to 546.6 ppm in the 1st, 2nd, 3rd and 4th instar, respectively. The tolerance ratio (TR), which is the TR of 90 percent lethal concentration (LC/ sub 90/) to the recommended concentration, was 0.04 to 0.8 in the 1 st, 0.2 to 7.5 in the 2nd, 0.7 to 115.3 in the 3rd and 1.2 to 485.4 in the 4th instars. Lower D$LC_{50}$ and DTR, which is the difference between the $LC_{50}$ and the TR of 4th and other instars, respectively, were observed in chlorfenapyr, chlorpyrifos and EPN while higher ones were lufenuron, chlorfluazuron and teflubenzuron. These results mean that insecticides with lower D$LC_{50}$ and DTR are effective in controlling larva of S. litura collected in Milyang, Korea.

• Korean Journal of Plant Resources
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• v.14 no.2
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• pp.108-115
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• 2001

For determining the effect of extracts exudated from ten industrial plant resources on germination and early growth of shoot and root of radish the allelopathic compounds screened. Germination rate and seedling growth of radish differed depending on plant species and extract concentration. Lower levels of 1% extracts exudated from industrial plant resources promoted the rate of germination of radish while higher levels of 10% extract inhibited the rate of germination. Germination rate, shoot growth and root growth of radish in higher concentration of extract also differed depending on the plant species exudated and extract concentraton of industrial plant resources. Higher concentration of extracts from Xanthium strutnarium L. Angellica gigas Nakai, and Solanum nigrum L. were completely inhibited the germination while those from Cichorium intybus L., and Polygonatum officinale Allioni were not inhibited. Extracts exudated from Xanthium strutnarium L, Angellica gigas Nakai, and Solanum nigrum L. showed the strong inhibition of shoot and root growth of radish while those from Cichorium intybus L., and Polygonatum officinale Allioni did not show the bioactivity in shoot and root growth of radish..

• 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.

• Research in Plant Disease
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• v.23 no.4
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• pp.348-354
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• 2017

To investigate occurrence of root-knot nematode (RKN) in plastic house of central area of Korea, 132 soil samples were collected in cucumber, water melon, tomato, red pepper and strawberry fields from 2013 to 2015. Among 132 soil samples, 65 soil samples (49%) were infested with RKN and mean density of RKN was 178 second-stage juveniles per $100cm^3$ soil (min. 1 ~ max. 3,947). The frequency of RKN by regional was the highest in Chuncheon with 80%, followed by Cheonan (68%), Nonsan (36%), Buyeo (33%) and Yesan (30%). The frequency of RKN by crops was the highest in tomato with 83%, followed by cucumber (61%), strawberry (41%), red pepper (30%), watermelon (26%). To identify the species of RKN, fifteen populations were selected for representative populations. As a phylogenetic analysis of 15 populations, southern root-knot nematode (Meloidogyne incognita), peanut root-knot nematode (M. arenaria) and northern root-knot nematode (M. hapla) were identified with 47%, 20% and 33% ratio, respectively. In crops, M. incognita, M. arenaria and M. hapla were detected in tomato, M. incognita and M. arenaria were detected in cucumber and watermelon, and M. hapla was detected in strawberry and lettuce. Thus, there should be a continuous management to major species of each crops to prevent dispersal of RKN damages.