• Korean journal of applied entomology
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• v.31 no.2
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• pp.182-189
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• 1992

The influnces of 9 kinds of solvents on the toxicities against several insect species, phytotoxicity and solubility of compounds were evaluated by means of leaf dipping and spray methods. In case of the spray application, density and vapor pressure seemed to be a contributing factor to lethal toxicity against brown planthopper and diamond-back moth, respectively; the bigger the property of density and the smaller the vapor pressure gave the stronger toxicity. It appeared that the toxicity of solvents was not correlated with anyone of physical properties such as boiling point, dipole moment, dielectric constant, surface tension and viscosity. Spray treatment gave more toxicity to insects than leaf dipping treatment. Although dielectric constant and dipole moment seemed to be contributing factors to phytotoxic damage to rice seedling and bean plants, respectively, no general correlation between phytoxicity and the other physical properties was found. Leaf dipping application caused stronger phytotoxicity than spray application. It is concluded that 5% acetone solution may be most suitable to test chemicals because of its favorable solubility of compounds, lower toxicity to insects, and lower phytotoxicity.

• Korean Journal of Environmental Agriculture
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• v.7 no.1
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• pp.52-57
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• 1988

This study was carried out to investigate the specific activity fo peroxidase(POD) in conjunction with the phytotoxic effect of the tolerant soybean(Glycine max Merr.) and the susceptible crabgrass(Digitaria adscendens(L.) Scopol.) to acifluorfen. The POD activity increased during the growth of soybean and crabgrass seedlings. But after the foliar application of acifluorfen, the POD activity in the treated leaves was considerably higher than in controlled leaves, suggesting that soybean had higher tolerance to acifluorfen with growth. All the treated soybeans recovered from herbicidal injury in 14 days after treatment, while all the treated crabgrasses were dead with extreme necrosis and leaf burning. It was measured that the POD activity of crabgrass increased abruptly in 1 to 2 days after treatment and then significantly decreased in 5 days.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.1
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• pp.55-59
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• 1989

Sodium methyl arsenate has been evaluated as a male sterilizing agent for the system of producing hybrid rice seeds. The compound was the most effective at the concentration of 0.02％. When applied as a foliar spray to four rice varieties at 15 days before heading, sodium methyl arsenate has produced 99％ male sterility. But the most effective time for application of the compound was 5 days before heading because of its phytotoxic effects. Effective application volume of the compound solution has depended on the growth of the plants treated. Varietal difference on the activity of the compound has been detected.

• Journal of Life Science
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• v.31 no.4
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• pp.430-441
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• 2021

Sesquiterpene lactones (STLs) are terpenoids found mostly in the Asteraceae family and are known for their strong cytotoxic properties, among other notable bioactivities. Some STLs, such as artemisinin and mipsagargin, are already commercially available and are used to fight malaria and tumor growth, respectively. Although the interest in STLs was low for a time after their discovery due to their toxic nature, past decades have witnessed a soar in STL-based studies focused on developing novel pharmaceuticals via chemical diversification. These studies have reported several promising physiological effects for STLs, including lower toxicity and diverse modes of action, and have demonstrated the antimicrobial, antioxidant, hepatoprotective, antiviral, antiprotozoal, phytotoxic, antitumor, and antiaging properties of STLs. STLs are mainly considered as valuable natural molecules for the fight against cancer since most STLs induce death of different types of cancer cells, as shown by in vitro and in vivo studies. Some STLs can also enhance the effects of drugs that are already in clinical use. Medicinal chemists use various STLs as starting molecules for the synthesis of new STLs or different bioactive compounds. All these developments warrant future research to provide more information on STLs, their bioactivities, and their mode of action. In this context, this review has summarized the bioactivities of some of the widely studied STLs, namely artemisinin, costunolide, thapsigargin, arglabin, parthenolide, alantolactone, cynaropicrin, helenalin, and santonin.

• Korean Journal of Environmental Agriculture
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• v.12 no.2
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• pp.162-168
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• 1993

This research was conducted to assess the influence of humic or fulvic acid on Bentazone phytotoxicity using a bioassay with hydroponically grown cabbage (Brassica campestris subsp. napus var. pekinensis Makino). Concentrations of Bentazone in the water culture media were ranged from 0 to 32 ${\mu}M $ and those of the organic ligands were 1.0mM as a soluble carbon. Media were prepared in a complete factorial combination with pHs of 4.5, 6.5 and 8.5. The phytotoxicity indices on growth rate and dry weight decrement were employed to evaluate the effects of organic ligands on the Bentazone phytotoxicity. Humic or fulvic acid without Bentazone treatment enhanced the growth of cabbage and this effect was evident at low pH of 4.5. Bentazone led to chlorosis and necrosis on cabbage leaves resulting in the decreases of dry and fresh weights and growth rate. This phytotoxic effect was increased with Bentazone concentration and evident at low pH. At pH 4.5, dry weight was decreased about 63% with 8${\mu}$M of Bentazone treatment. Effective concentration of Bentazone causing 50% decreases in fresh weight as compared to the control was estimated to be 21${\mu}$M. Presence of organic ligand reduced the phytotoxicity of Bentazone to cabbage significantly by increasing yields and growth rates as compared to the treatment of Bentazone alone. At pH 4.5, fulvic acid reduced phytotoxicity of Bentazone upto 46%, and this efficiency of fulvic acid was better than that of humic acid under the same condition.

• The Korean Journal of Pesticide Science
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• v.3 no.1
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• pp.1-12
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• 1999

Herbicidal activities of newly synthesized experimental compound, KSC-13906 [Erythro N-{(4,6-dimethoxy pyrimidin-2-yl)aminocarbgnyl}-2-(2-fluoro-1- hydroxy-n-propyl)benzenesulfonamide, US Patent 5,461,025], were investigated in greenhouse and field for development as a paddy herbicide. KSC-13906 exihibited excellent weeding effects and selectivity to rice under submerged paddy condition in geenhouse. At the application rate of $2.5{\sim}5$ g ai/ha treated on surface of water, KSC-13906 effectively controlled three annual weeds such as Echinochloa crus-galli var. oryzicola. Scirpus juncoides, and Monochoria vaginalis as well as five perennial weeds such as Cyperus serotinus, Sagittaria pygmaea, Eleocharis kuroguwai, Potamogeton distinctus, and S. trifolia. However, there was no effect on Aneilema keisak and Lindernia procumbens. Especially, KSC-13906 effectively controlled Echinochloa crus-galli var. oryzicola at growth stages ranging from pre-emergence to 3-leaf stage. Antagonistic interaction was found between pyrazosulfuron-ethyl and mefenacet, but not between KSC-13906 ana mefenacet. KSC-13906 had high selectivity to transplanted rice, but caused phytotoxic effect on direct-seeded rice when treated before 3-leaf stage. Herbicidal activity of KSC-13906 on the Echinochloa crus-galli var. oryzicola was 7-folds greater than that of pyrazosulfuron-ethyl in terms of relative dose ratio of the herbicides. These results suggest that KSC-13906 possesses selective herbicidal potency in rice.

• Korean Journal of Weed Science
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• v.7 no.2
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• pp.156-164
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• 1987

Allelopathic activity of dominant upland weed species was determined using aqueous and methanol extracts and dried residues of the weeds. Germination and seedling growth of radish (Raphanus sativus L.) and sesame (Sesamum indicum L.) were greatly inhibited by 2% (w/v) aqueous extracts of Artemisia asiatica Nakai and Portulaca oleracea L., respectively. Great phytotoxicity on both indicator plants occurred by 2% (w/v) aqueous extracts of Capsel/a bursa-pastoris (L.) Medik. A complete inhibition in germination and seedling growth of radish was caused by 2% (w/v) methanol extract of A. asiatica. There was about 90% inhibition in germination and seedling growth of sesame due to 2% (w/v) methanol extracts of A. asiatica, P. oleracea and Trifolium repens L. Phytotoxic effects varied with extract solution, weed species and indicator plants employed, indicating that the weed species contained different contents and kinds of allelopathic chemicals. Water potential and pH adjusted to those of the extracts did not affect germination and seedling growth of the indicator plants. Phytotoxicity increased with increasing concentration of the extracts obtained from four suspected alleopathic weeds. Soil-incorporated plant residues of A. asiatica and P. oleracea caused greater phytotoxicity on radish than those of C. bursa-pastoris and T. repens.

• Journal of Bio-Environment Control
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• v.32 no.3
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• pp.242-248
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• 2023

This study was conducted to evaluate the effects of trinexapac-ethyl (TE) and prohexadione-calcium (PC) on the growth and turf quality of perennial ryegrass (Lolium perenne L.). Treatments were designed as follows; control (non-treatment), TE (TE 0.01 a.i. g·m^-2·100mL^-1), and PC (PC 0.01 a.i. g·m^-2·100mL^-1). Compared with control, turf color index and chlorophyll content of TE and PC treatments were not significantly different. As applied plant growth regulators (PGRs), shoot length in the TE and PC was decreased by 8.9-12.4% and 6.7-13.6%, respectively, and clipping yield by 44.4-45.8% and 40.6-40.9%. When evaluated with the growth of shoot length after applying PGRs, residual days of TE and PC were 43.6 and 37.9 days after treatment of PGRs (DAT) in the 1st experiment (July 29-August 26), respectively, and 38.3 and 39.5 DATs in the 2nd experiment (September 30-October 28). These results indicated that an application of TE or PC decreased shoot length and clipping yield in the perennial ryegrass, and their residual time was about 40±3 DATs. Perennial ryegrass applied with PGRs like TE and PC was not significant seasonal difference, and might be not phytotoxic.

• Korean Journal of Environmental Agriculture
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• v.14 no.3
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• pp.263-271
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• 1995

Chemical assessment of soil pollution with heavy metals was made by analyzing the changes in pH, ionic strength, cationic concentration and chemical species in the soil solution. Saturated pastes of the unpolluted soils were made by adding solutions containing Cu or Cd and the final Cu or Cd concentrations were in the range of 0 to 400 mg/kg. After equilibrating for 24 hours at $25^{\circ}C$, the soil solution was extracted from the saturated pastes by the vacuum extraction method and analyzed for pH, electrical conductivity, Cu, Cd, cations and inorganic ligands. Chemical species in soil solution were calculated by the GEOCHEM-PC program employing the input variables of pH, ionic strength(${\mu}$), molar concentrations of cations and ligands. Increasing Cu or Cd additions lowered pH of the soil solution but increased concentrations of Ca, Mg and K resulting in increases of ${\mu}$ of the soil solution. Effects of Cu on lowering pH and increasing ${\mu}$ were greater than those of Cd. Concentrations of Cu or Cd in soil solution were relatively very low as compared to those of additions, but increased linearly with increasing additions representing that concentrations of Cu were higher than those of Cd. At 400 mg/kg additions, concentrations of Cu were in the range of 0.51 to 11.70 mg/L but those of Cd were 34.4 to 88.5 mg/L. Major species of Ca, Mg and K were free ions and these species were equivalent to greater than 95 molar % of the existing respective molar concentrations. These cationic species were not changed by Cu or Cd additions. Major species of Cu in lower pH soils such as SiCL and SL were free $Cu^{2+}$ (>95 molar %), but those in LS having a higher pH were free $Cu^{2-}$ and Cu-hydroxide complex. At 100 mg Cu/kg treatment, $Cu^{2+}$ and Cu-hydroxide complex were equivalent to 73 and 22.4 molar %, respectively. These respective percentages were decreased and increased correspondingly with increasing Cu treatments. Major species of Cd in soil solution were free $Cd^{2+}$ and Cd-chloride complex, representing 79 to 85 molar % for $Cd^{2+}$ and 13 to 20% for Cd-chloride complex at 10 mg Cd/kg treatment. With increasing Cd additions to 400 mg/kg, $Cd^{2+}$ species decreased to $40{\sim}47%$ but Cd-chloride complexes increased to $53{\sim}60$ molar %. These results demonstrated that soil contamination with heavy metals caused an adverse effect on the plant nutritional aspects of soil solution by lowering pH, increasing cations temporarily, and increasing free metal concentrations and species enough to be phytotoxic.

• Asian Journal of Turfgrass Science
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• v.19 no.2
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• pp.65-72
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• 2005

Creeping bentgrass (Agrostis palustris Huds.) had been the problematic weed for Kentucky bluegrass (Poa pratensis L.) fairway since it shows light green color all year. Experiment was carried out to determine the best herbicides combination to control creeping bentgrass in Kentucky bluegrass. fairway without injury. To investigate the efficacy of herbicides, five post-emergence herbicides of asulam WG ($87.6\%$), imazaquin SL ($20\%$), fenoxaprop-P-ethyl EC ($7\%$), mecoprop SL ($50\%$), triclopyr-TEA SL ($30\%$) and one pre-emergence herbicide pendimethalin EC ($31.7\%$) treated on 21 Sept. and 10 Nov. 2003. Kentucky bluegrass visual quality evaluated 30 and 50 days after application for phytotoxic effects of the herbicides. As a result, asulam WG (0.2g/$m^{2}$) and imazaquin SL (0.3ml/$m^{2}$) showed approximately $90\%$ of control in creeping bentgrass, but visual quality of Kentucky bluegrass significantly decreased from 20 to 50DAT (day after treatment). However, creeping bentgrass was acceptably controlled(over $80\%$) by fenoxaprop-P-ethyl EC (0.4ml/$m^{2}$)+triclopyr-TEA SL(0.3 ml/$m^{2}$) applied twice on 21 Sept. and 1 Oct. 2003 without serious injury on Kentucky bluegrass. Therefore, it is suggested that an application of fenoxaprop-P-ethyl EC (0.4ml/ $m^{2}$)+triclopyr-TEA SL (0.3 ml/$m^{2}$) may be more effective to control creeping bentgrass in Kentucky bluegrass with the least phytotoxicity by herbicides.