• Journal of agriculture & life science
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• v.53 no.1
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• pp.13-21
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• 2019

This study was carried out to acquire basic data for a long-term hydroponic culture through investigating water and inorganic ion uptake characteristics at different EC level of nutrient solution of three tomato varieties. Three different tomato varieties, the European type(cv. Daphnis), the Asian type(cv. Super Doterang) and cherry type(cv. Minichal), were used for the investigation. Also, the deep flow technique(DFT) was applied. The three different electrical conductivity(EC) level(1.0, 2.0, 3.0, and 4.0 dS·m-1) of hydroponic nutrient solution were used as variable. At a high EC level of nutrient solution, the leaf area and fresh weight decreased in the early stage, and its growth(plant height, leaf number, leaf area, fresh-weight) was poor with salt stress. Result showed that the higher the EC level of the nutrient solution, the lesser was water uptake. The water uptake was not significantly different from varieties in the first survey, but In the second survey, the 'Daphnis' did not show a significant decrease in water uptake in the EC level higher than 2.0 dS·m-1., on the other hand, 'Super Doterang' presented very low water uptake. At a low EC level, N, P, and K, were absorbed more than the concentration of the irrigation water, while Ca, Mg, S uptake were low. At a high EC level, almost ions absorbed less than 50% of the initial concentration of irrigation water. Thus, imbalance among ions was severe at low EC level compared to high EC level. 'Daphnis' was a variety that effectively utilize nutrients under nutrient stress, showing high absorption at low concentration condition and low absorption at high concentration condition. However, 'Daphnis' suffered most seriously by absorbing nutrients excessively.

• Korean Journal of Food Science and Technology
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• v.45 no.4
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• pp.391-402
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• 2013

Pesticide residues in agricultural products in Korea were evaluated to create a data base to inform food policy. Pesticide residues were investigated in 17 commodities collected from 9 provinces in 2012. Our analytical method of multiresidue analysis, involved the analysis of individual recovery, linearity, limit of detection, and limit of quantitation of 60 pesticides in six matrices. The pesticides, including acetamiprid and forchlorofenuron, were evaluated in 358 agricultural samples by liquid chromatography/tandem mass spectrometry. Twenty three pesticides were detected from 67 samples. The results showed that the ratio of estimated daily intake to acceptable daily intake was 0.00009-0.0861% by the intake assessment, which means that residual pesticides in agricultural products in Korea are properly controlled.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.763-771
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• 2000

The 88 kinds of pesticide residues were analyzed in 12 kinds(289 samples) of fruits and vegetables brought at department store & mart in Kwangju from Feburary to September in 1999. The detection rate of pesticide residue in 12 kinds(289 samples) of fruits and vegetables was 21.1%, and the rate exceeds standard was 5.2%. The order of highly exceed rate in fruits and vegetables were perilla leaf, lettuce, spinach and chickery. The order of pesticide which founded frequently in fruits and vegetables were procymidone, endosulfan, vinclozoline, chlorpyrifos, cyprermethrin, pirimiphos-M, fenvalerate, fenarimol, and monocrotophos. And that of pesticide which exceed highly standard were procymidone, vinclozolin, endosulfan, pirimiphos-M, fenarimol, monocrotophos, etc. Eight different washing methods were compared for removal efficiencies of residual pesticides(procymidone, vinclozoline) on the perilla leap, the lettuce, the spinach, the strawberry, and the minitomato. Residual pesticides such as procymidone and vinclozoline were removed most efficiently by ultrasonic washing.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.408-412
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• 2013

This study was carried out to investigate damp injury caused by tomato coir bag culture and prevent that. The tomato variety was used 'Minichal', and tomatoes were grown in greenhouse. The nutrient solution based on Yamazaki Tomato Standard Solution was irrigated from one hour after sunrise to two hour before sunset. The slits for darainage were made in three types; I, L, and bottom slit type. The coir bag of I and L type had six slits of 15cm length, that of bottom slit type had three slits of 15 cm length. The weight of coir bag in 24 hours after saturation was 14.2 kg in I type, 13.8 kg in L type, and 12.8 kg in bottom slit type, but there was not significant difference. The weight of coir bag after one day irrigation was 14.5 kg, 14.2 kg, and 13.3 kg at L, I, and bottm slit type, respectively. This means that the moisture content of coir bag during cultivation was lowest in bottom slit type. The number of adventitious root on stem was 160, 170, and 53 at I, L, and bottom slit type, respectively. The dry weight of root and root length were highest at bottom slit type, compared to other treatment. The marketable yield was highest 26.5 kg/20 plant in bottom slit type. For increasing yield and preventing damp injury, bottom slit type was most effective at U type bed coir bag culture.

• Journal of the Korean earth science society
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• v.27 no.1
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• pp.95-117
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• 2006

From the Tertiary Yeonil Group distributed in Songra and Cheongha areas, the northern part of the Pohang Basin, nine archaeomonad species belonging to two genera, and other three types of chryophycean cysts considered as stomatocysts, five endoskeletal dinoflagellate species belonging to three genera and eighteen ebridian species belonging to eleven genera were identified. Based on above siliceous microfossil assemblages, the Yeonil Group is corresponded to Middle Miocene age. The group is correlated with the Calvert Formation (Maryland in USA) and the Hojuji Formation (in Central Japan) by its archaeomonad cysts. And, the group is correlated with the intervals of Actiniscus elongatus to Middle Hermesinella conata zones in Southwest Pacific region and of Spongebria miocenica to Middle Hermesineila schulzii zones in $V{\o}ring$ Plateau, Norwegian Sea, based on the ebridian assemblages of the group. From the chrysophycean cyst including archaeomonad, endoskeletal dinoflagellate and ebridian assemblages in the Yeonil Group of the study area, it is inferred that cold water masses dominated during the deposition oi the group with occasional warm water. The upper part of the group might be somewhat colder than the lower one of the group in depositional condition. In addition, minute chrysopycean cysts considered as stomatocysts suggest the influence of fresh or brackish water during the deposition of the group.

• Journal of Food Hygiene and Safety
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• v.20 no.3
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• pp.159-164
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• 2005

This method was described for the simultaneous determination of simetryn and buprofezin in rice, vegetables, and fruits by gas chromatography(GC) with nitrogen phosphorus detector. The GC method of simetryn and buprofezin was shown to give a linear detection ranges between $0.019\sim9.306mg/kg,\;0.023\sim11.27mg/kg$, respectively. For evaluation of GC method, simetryn spiked into rice, vegetables and fruits at the level of 4.653mg/kg was determined. The recoveries of simetryn by GC method were ranged from 57.9 to $115.9\%$. For evaluation of GC method, buprofezin spiked into rice, vegetables and fruits at the level of 2.817mg/kg was determined. The recoveries of buprofezin by GC method were ranged from 56.5 to $121.5\%.$

• Korean Journal Plant Pathology
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• v.2 no.3
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• pp.193-198
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• 1986

Bottom rot of Chinese cabbage (Brassica pekinensis Rupr) hitherto undescribed in Korea is caused by Rhizoctonia solani Kuhn. Development of bottom rot in fall crops was observed and the efficiencies of fungiciial control in naturally infested field in Southern region were studied. Bottom rot symptom started to develop 20 days after transplanting 20 day old seedlings, which corresponded to the middle growing stage. At the reading stage, the infection rate increased substantially, which progressed upto an average of $52\%$ at harvesting time. The overall infection rate was about $30\%$ in Chinese cabbage field under plastic film house cultivation. However, disease intensity of fall crops was less severe than that of crops in plastic film house. where plants infested earlier, stunted and their growth was extremely poor. Optimum temperature for mycelial growth of bottom rot isolates of R. solani was $20\~25^{\circ}C$ on potato-sucrose agar. This fungus was highly pathogenic on seedlings of Chinese cabbage, radish, sesame and rape resulting in high percentage of damping-off. For other crops, such as lettuce, tomato the cucumber, the germination was delayed for 2-3 days and the percentage damping-off was lower. Anastomosis group of this fungus was idenlfied as AG II-I. Soil drenching of fungicide pencycr WP., three applications at 10 day interval, was effective; indicating the most promising one with control value $80\%$.

• Korean journal of applied entomology
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• v.58 no.4
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• pp.341-345
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• 2019

Ethyl formate (EF) is a rapid kill, environmentally safe, and low mammalian toxicity fumigant, registered to disinfest quarantine insect pests from imported agricultural products. A new concept for controlling insect pests of agricultural crops was tested in a fumigation chamber with EF. Control efficacy of and phyto-toxicity due to EF fumigation were evaluated against four pests (Thrips palmi, Bemisia tabaci, Myzus persicae, and Tetranychus urticae) and on seedlings of four fruit vegetables (FVs; yellow melon, cucumber, tomato, and pepper). Ethyl formate fumigation at a dose of 1.5 g m^-3 for 12 h produced >93.3% mortality in T. palmi, B. tabaci, and M. persicae. However, T. urticae was tolerant to fumigation, showing only 20% mortality at 2.0 g m^-3. In terms of concentration × time (CT) products, at least 8.9 g·h m^-3 CT at 20 ± 1.5℃ was needed to achieve > 90% mortality against the three susceptible insect pests. Fumigation at 1.5 g m^-3 for 12 h caused no phyto-toxicity to any of the four FV seedlings. Ethyl formate application, as a new disinfestation method in greenhouses, could be an alternative to reduce the use of conventional insecticides. However, further studies are needed to determine the efficacy of this method at different pest developmental stages and in different greenhouse environments. Additionally, research is needed to elucidate the phyto-toxicity of EF application at different growing stages of a wide variety of crops.

• Korean journal of applied entomology
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• v.17 no.2 s.35
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• pp.89-98
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• 1978

A study on the root-knot nematodes (Meloidogyne spp.) affecting economic crops in Korea was undertaken to know the distribution of the nemic fauna. Total 66 samples were taken from soil and root of 24 host plants at different localities in 4 provinces. Four Meloidogyne species such as Meloidogyne hapla, Meloidogyne arenaria, Meloidogyne incognita and Meloidogyne javanica were identified and some morphological characteristics were described. One of these, Meloidogyne javanica was reported newly in Korea from Horticultural Experimental Station, Suweon, Gyeong Gi on potato, Geomsadong, Daegu on chinese cabbage, Sangeogdong, Daegu, Gyeong Bug on violet and Choeumri, Namhae, Gyeong Nam on pumpkin. In Jae Ju province, Meloidogyne incognita was only found except the other three species. The most common and widely distributed Meloidogyne species in Korea is Meloidogyne hapla by $50\%$ in total, next Meloidogyne incognita $33.3\%$ Meloidogyne arenaria $10.6\%$ Meloidogyne javanica $6.0\%$ in turn, The root-knot nematodes infected the most severely in Jae Ju province and Gyeong Nam, Gyeong Bug and Gyeong Gi province in turn. Twenty four plants were attacked by root-knot nematodes among them important economic crops are soybean, peanut, potato, tomato, cucumber, carrot, pumpkin, wateremelon, edible burdock, pepper, eggplant, cabbage, lettuce and tobacco in Korea.

• The Korean Journal of Pesticide Science
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• v.3 no.1
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• pp.20-28
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• 1999

Chloronicotinyl derivatives were synthesized by substitution of amino in 3-pyridylmethylamine with phosphite groups and their insecticidal and fungicidal activities were determined. At 500 ppm, compound 4 with methyl and butyl group in phosphonate and compound 5, 6, 7, and 8 with two butyl, 2,2,2-trifluorotehtyl, 2-ethylhexyl, phenyl, respectively, in phosphonate showed 90% insecticidal activities against brown plant-hopper (Nilaparvate lugens). These compounds showed, however, poor insecticidal activities against diamond-back moth (Plutella xylostella) and two-spotted spider mite (Tetranychus urticae) (<65%), suggesting that insecticidal activity of chloronicotinyl derivatives containing phosphorus moieties are species-dependent. Newly synthesized chloronicotinyl derivatives with halogen and/or heterocycle (compound $10{\sim}21$) did not show insecticidal activities. We also determined fungicidal activity of the synthesized chloronicotinyl derivatives against rice sheath blight (Pyricularia grisea), cucumber gray mold (Bortytis cinerea), tomato late blight (Phytophthora infestans), wheat leaf rust (Puccinia recondita), and barley powdery mildew (Erysiphe graminis). Compound 10 with butyl and 4-nitrophenyl in phosphonate at 10 ppm showed 85% fungicidal activity against rice blast, suggesting that chloronicotinyl derivatives containing phosphorus moieties could be developed as a fungicidal agent of a novel chemical structure.