• The Korean Journal of Pesticide Science
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• v.19 no.3
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• pp.248-254
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• 2015

Uptake of the triazole fungicides, fluquinconazole and tetraconazole from shoot part of onion was assessed by determining residual amounts of applied fungicides in edible and shoot parts of onion after the foliar application. Combined product of fluquinconazole and tetraconazole (14:7, v/v) as a 21% active ingredient of suspended emulsion formulation was diluted at ratio of 500 and 200 times and sprayed on the shoot part of onion after sealing its root part with absorbent paper. At 10 days after the pesticide application, fluquinconazole residue in the shoot part was the greatest as 5.2 mg/kg at 200 times-dilution treatment, while tetraconazole residue in this part was the smallest as 1.2 mg/kg at 500 times-dilution treatment. On the other hand, the pesticide residues in edible parts of onion at all the treatments were less than limits of detection, 0.01 mg/kg. However, fluquinconazole residues in the edible part of onion divided into three groups such as 1st, 2nd, and 3rd layers were detected at concentrations of 0.04 or 0.24 mg/kg, and these results show the different distribution of pesticides in onion depending on divided layers. In addition, chopped onions were soaked in pesticide solutions prepared with dilution of 1,000 times, cooked using three food processing types such as boiling, stir frying, and pickling, and the pesticide residues in them were analyzed. The analyzed results showed the largest pesticide dissipation in onion followed boiling process (76.9~92.6%).

• The Korean Journal of Ecology
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• v.16 no.4
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• pp.409-416
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• 1993

After spraying simulated sulphuric acid rain (SSAR) to the leaves of Glycine max, Quercus aliena var. pellucida and Pinus rigida, the leachates were consecutively collected and quantitatively determined for the concentration of K and Ca. The amount of the leached ion decreased with subsequent acid treatment for all plants. But as the pH of SSAR decreased, the amount of the leached ion increased. The cumulative quantities of K leached from each species were 1.04 to 1.46 times higher at pH 4.0, 1.09 to 1.58 times higher at pH 3.5 and 1.24 to 2.03 times higher at pH 3.0 compared with pH 5. 6 treatments. The cumulative quantities of Ca leached from each species were 1.23 to 1.47 times higher at pH 4.0, 1.50 to 1.92 times higher at pH 3.5, and 2.45 to 3.30 times higher at pH 3.0 compared with pH 5.6 treatments. The Ca /K ratio in 1000 ml leachate was 1.10 to 2.91 for Q. aliena var. pellucida and 1.68 to 2.98 for P. rigida, but 0.66 to 0.91 for G, max. The Ca /K ratio in 1000 rnl leachate increased for all three species, as the pH of SSAR decreased. Foliage analysis after acid rain treatment showed leaching effect at pH 3.0.

• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.228-235
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• 2014

The residue levels of flonicamid and its metabolites, 4-(trifluoromethyl)nicotinic acid (TFNA) and N-4-(trifluoromethyl)nicotinoyl glycine (TFNG) in sweer pepper were investigated to examine the residual characteristics of analytes for 87 days after pesticide application. The pesticide was applied once at recommended dosage and double dosage by foliar sprays and the samples of fruits and leaves of sweet pepper were collected for each treatment. The residues of flonicamid in all of fruits and leaves decreased gradually over time, while the residue levels of TFNG metabolite exhibited tendency that increased for long periods and thereafter decreased. Total flonicamid residual concentrations containing metabolites residues in fruit samples increased consistently until 30 days post-application and higher residue levels than residues at 1 day post-application were detected from 30 day to 87 day after treatment. The residue pattern observed in fruit could be explained by the movement of TFNG from leaves to fruits of plant. Such residual characteristic was similarly found in samples treated both recommended dosage and double dosage.

• Journal of Bio-Environment Control
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• v.12 no.2
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• pp.72-76
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• 2003

This study was conducted to estimate stimulation of plant growth of green and red leafy lettuces (Lactuca sutiva L. cv. Chungchima and Jugchima) at affected by covering method and time with protected film materials containing concentrated PO film and GA$_3$ foliar spray. Plants were covered with ‘Pasraido’ material from October 26 to November 31 (direct 1), from November 5 to November 31 (direct 2), or with a tunnel, or direct 2＋ tunnel. Mean air temperature and relative humidity under the covering were higher in direct and tunnel, direct and non-covering, in that order. The fresh weight and dry weight of red and green lettuces increased in direct and tunnel followed by direct 1, direct 2, tunnel and the control. GA$_3$ treatment promoted the growth in all covering methods, but decreased the chlorophyll contents. Fresh weight and dry weight were higher in red lettuce than in green lettuce in the control.

• Korean Journal of Environmental Agriculture
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• v.15 no.3
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• pp.325-334
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• 1996

Pepper plants were flooded at 0, 5, 10 and 15cm at seedling stage under the condition of greenhouse. Treatment of flooding times are 6, 12, 24, 48 and 120 hours. The results obtained are summarized as follows. Plant height, number of leaves, shoot and root fresh weight were not recovered the flooding damages regardless of flooding time and depth. Pepper plant died in flooding depth of 5cm or more for over 48 hours. Plants in fallen leaves were found at more than 5cm depth and 6 hours of floodings. Photosynthesis and respiration rate decreased in the 5cm flooding depth or more for 24 hours. Chlorophyll content and root activity decreased for 12 hours or more at all the flooding depth. Also, diffusion resistance of stomata cell increased as increased flooding time and depth. Diseases occurred remarkably in proportion to the depth and hours of flooding treatment. It was not possible to control the desease by fungicide, also then was no effects of foliar spray of urea. Weight of fruit per plant not decrease by the 12 hours of 0cm and the 6 hours of 5cm flooding but decreased at deeper and longer flooding. Average weight of a fruit increased. The yield could not expected in the depth of 5cm or more for over 48 hours, There was significant positive correlation between all the investigated characteristics of growth and yield. There was, however, negative correlation between number of leaf and diffusion resistance of stomata.

• Korean Journal of Weed Science
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• v.4 no.2
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• pp.211-218
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• 1984

In order to establish the chemical weed control systems in orchard, field experiments were conducted to evaluate the effects of spray methods and mixing of herbicides. The mixtured dosage of glyphosate 100cc/10a and 2,4-D 75㏄/10a showed higher control effects than mono-treatment of glyphosate and paraquat on Artemisia vulgaris var. indica and Polygonum hydropiper L. And oxyfluorfen was more effective in reducing the cover rate and dry weight of weeds than simazine and alachlor on 75th day after treatment. In the mixing experiment of land and foliar appling herbicides. The effect of glyphosate on May 17 followed by oxyfluorfen on June 12 showed the best control effect.

• Korean Journal of Weed Science
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• v.31 no.3
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• pp.240-249
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• 2011

The potential of juglone a plant naphthoquinone as a natural herbicide on new target, 7-keto-8-amino pelargonic acid synthetase (KAPAS) in the early step of biotin biosynthesis pathway, was performed in vitro and in vivo. Juglone effectively inhibited KAPAS activities in vitro and the $IC_{50}$ was $9.5{\mu}M$. Foliar application of juglone showed very good herbicidal activity to the eight-tested weed species. Among them, Solanum nigrum was completely controlled at a concentration of $250{\mu}g\;mL^{-1}$ with main symptoms of desiccation or burndown. Digitaria sanguinalis and Aeschynomene indica were also sensitive to juglone treatment. All eight weed species were controlled by 90~100% at a concentration of $500{\mu}g\;mL^{-1}$. However, soil application of juglone to Digitaria sanguinalis did not show any herbicidal symptoms. Cellular leakage from cucumber leaf squares treated with juglone increased depending on the concentrations increased from 6.25 to $100{\mu}M$ after 24 hours incubation with or without light. However, chlorophyll loss in cucumber leaf squares was negligible. Biotin supplements significantly rescued the inhibition of germination rate of Arabidopsis thaliana seeds previously inhibited by the juglone. Our results suggest that the juglone is a possible environmental friendly herbicide candidate with a new target KAPAS inhibiting activity.

• Journal of Plant Biotechnology
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• v.32 no.2
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• pp.97-103
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• 2005

Antioxidative responses of transgenic tobacco plants expressing both superoxide dismutase (SOD) and ascorbate peroxidase (APX) in chloroplasts was investigated with several herbicides. In greenhouse test, tolerance of SOD/APX-overexpressed tobacco (CA) to photosystem (PS) I inhibitor paraquat was increased by about 40%. However, any response differences between CA and wild type (WT) tobacco was not observed in a treatment with PS II inhibitors (bromoxynil, diuron and bromacil), chlorophyll biosynthesis inhibitor(oxyfluorfen), carotenoid biosynthesis inhibitor (fluridone) and 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase inhibitor (glyphosate). This tendency was also similar in the growth chamber test of low light intensity, using paraquat and diuron. That is, increased antioxidant activity of CA was shown only in paraquat treatment. When paraquat was foliar-treated to 6 to 9-leaf stage plant, the third to fourth placed leaf from shoot tip showed relatively higher antioxidant activity. Ascorbate supplemented to paraquat solution alleviated the phytotoxicity with a similar range in both CA and WT. In conclusion, CA specifically responded to oxidative stress induced by paraquat among tested herbicides in a whole plant assay.

• Korean Journal of Agricultural Science
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• v.6 no.1
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• pp.21-26
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• 1979

To compare the effect of dikegulac (sodium 2,3 : 4, 6-di-O-isopropylidene-2-keto-L-gulonate) and ancymidol (${\alpha}$-cyclopropyl-${\alpha}$-(4-methoxyphenyl)-5-pyrimidinemethanol) on the growth and flowering responses of Salvia splendens cv. Bonfire, foliar spray of dikegulac at rates of 0.06 and 0.12% and ancymidol at rates of 50 and 100 ppm, and soil drench of ancymidol at rates of 0.1 and 0.5 mg/pot were treated. Dikegulac reduced the plant height and induced the lateral shoot development by disrupting apical dominance, and thus increased the number of inflorescences and retarded flowering date. Dikegulac treatment greatly increased chlorophyll content of leaf, especially chlorophyll a. Ancymidol reduced the plant height without disrupting apical dominance and retarding flower ing date, but did not increase inflorescence number except soil drench at rate of 0.1 mg/pct. Ancymidol treatment significantly increased chlorophyll content of leaf, especially chlorophyll a. Dikegulac can be effectively used as a pinching agent and branching agent for salvia.

• Korean Journal of Weed Science
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• v.5 no.1
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• pp.43-49
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• 1985

This study was conducted to investigate the existance of dormancy in newly collected tubers of Eleocharis kuroguwai Ohwi from paddy fields and to determine the effect of various growth regulators on the bud sprouting and tuberization of E. kuroguwai. The maximum percent sprouting of E. kuroguwai collected at every month during winter was less than 60% regardless of varied collection tunes until 50 days after incubation, suggesting the presence of dormancy in E. kuroguwai tubers. This dormancy was markedly broken as the time went by, probably due to the exposure of tubers the extremly low temperature. The treatment of $BA10^{-3}M$ and $BA10^{-3}+GA10^{-6}M$ increased bud sprouting about 10 and 11 times, respectively, than that of the untreated control indicating that BA seems to be one of the most effective agents among the growth regulators used on the bud sprouting of E. kuroguwai. Foliar application of BA increased tuberization of E. kuroguwai by an average of 34.4% as compared with the untreated control. The highest increase, 39.8% was obtained with BA treatment at $10^{-5}M$.