• The Korean Journal of Pesticide Science
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• v.12 no.1
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• pp.74-81
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• 2008

To elucidate the exposure of pesticide in agricultural environment and to investigate distribution of pesticide in paddy fields. This experiment was carried out to clarify pesticide distribution in paddy fields applied with different formulations and growing stages. Initial dissipation rate of applied butachlor EW and oxadiazon EC before rice planting were more than 90% within 3 days in paddy fields. The distribution of a.i. in the pesticide formulations tested depended upon the elapsed time at each growing stage of rice plant after application. Most of pesticides applied within 15 days after transplanting of rice seedlings, more than 95%, were located in the surface water and soil regardless of pesticides; butachlor, thiobencarb and molinate GR. The distribution of iprobenfos GR, tricyclazole WP and phenthoate EC, after application 2 hours in middle growing stage (46 days after rice planting) were shown as 16.1, 48.9 and 38.9% in surface water, 83.6, 15.4 and 10.7% in soil, and 0.3, 35.7 and 50.4% in rice plants of paddy fields, respectively. Also tricyclazole WP and phenthoate EC, after application 2 hours in the late rice growing stage (90 days after rice planting) were distributed to 7.8 and 9.8% in surface water, and 21.7 and 5.1% in soil, and 70.5 and 85.1% in rice plants of paddy fields, respectively.

• The Korean Journal of Pesticide Science
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• v.14 no.3
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• pp.284-288
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• 2010

A series of experiments was carried out for selecting insecticides and determining proper spraying time to control pea weevil (Bruchus pisorum Linnaeus) in Jeonnam area. In the field trial two times spray with diazinon, carbaryl, imidacloprid, spinosad, etofenprox, clorpyrifos-methyl showed good control effect and threetimes spray showed the better control effect. The second spray (spraying on 10th of May) took the major role of insecticide effectiveness expression for controlling pea weevil. Further trial for selecting insecticides among organophosphates to control pea weevil in lab was conducted and every organophosphate insecticide tested was very effective to pea weevil even at the concentration of one forth of its recommending concentration.

• Korean Journal of Weed Science
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• v.18 no.4
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• pp.341-347
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• 1998

This study was carried out to investigate the effect of U-Granule formulation of molinate(S-ethylhexaphdro-1H-azepine-1-carbothioate) mixtures in green house and paddy field, Five minutes were taken for U-Granule to spread out 7m in irrigated water of direct seeded on flooded paddy surface. The concentration of active ingredient of molinate in molinate U-Granule application was similar to molinate+simetryn U-Granule application. But weeding effect of molinate+simetryn U-Granule on Echinochlor crus-galli was 23% higher Than single application of molinate at 7m from application point. Bioefficacy of molinate+simetryn+imazosulfuron U-Granule on control of Echinochloa crus-galli was higher than that of molinzte+imazosulfuton U-Granule, but those effect on Eleochairs kuroguwai was not significantly different. Only slight rice phytotoxicity was observed at 5m and 2m from application point of U-Granule molinate+simetryn+imazosulfuron and molinate+imazosulfuron, respectively. So it is concluded that there is little phytotoxicity problem in practical application of U-Granule of molinate mixtures.

• Research in Plant Disease
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• v.14 no.2
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• pp.117-121
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• 2008

To determine the economic threshold level of Meloidogyne incognita on cucumber in greenhouse conditions, cucumber seedlings(Cucumis sativa L. cv. 'Super Manchon') grafted on 'Jangsushintozoa'(Cucurbita maxima x Cu. moschata) were planted in wooden boxes($30{\times}40{\times}15cm,\;L{\times}W{\times}D$) under a plastic house in August 01 and harvested from Sep. 01-Oct. 30, 2006. The initial nematode population densities(Pi) in the wooden boxes were adjusted to 0, 10, 30, 100, 300, and 600 second-stage juveniles(J2)/100 $cm^3$ soil. The relationship of total fruit yield to Pi level could be adequately described by a linear regression equation, $Y=0.82-0.04{\cdot}Log_{10}$(Pi+1). Initial nematode densities(Pi) before planting in excess of 5 J2/1,000 $cm^3$ soil caused in total yields loss that is equivalent to the costs of granular nematicide application; Pi level in excess of 25 J2/1,000 $cm^3$ soil caused in total yields loss that exceed the costs for application of fumigants at current control costs. We propose two different management strategies depending on nematode densities, (i) application of non-fumigant granular nematicides for M. incognita Pi level of 5 J2/1,000 $cm^3$ soil and (ii) fumigant treatment with Pi level over 25 J2/1,000 $cm^3$ soil. Soil samples to determine population density of Meloidogyne spp. for advisory purposes should be taken several months before planting time, which allows a period of time enough for implementing management procedures.

• Weed & Turfgrass Science
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• v.2 no.4
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• pp.362-367
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• 2013

This study was conducted to develop an efficient control method for water foxtail in the field sowing barley and wheat seeds before rice harvesting. When thifensulfuron-methyl (75%) was applied 0, 5 and 10 days after rice harvesting, little phytotoxicity was observed on both barley and wheat. Percent of water foxtail control with thifensulfuron-methyl (75%) was more than 88% at three different application timing. When butachlor (5%) was applied 5 days before barley and wheat sowing, phytotoxicity on barley and wheat was severe. However, no phytotoxicity was observed on barley and wheat 5 and 10 days after rice harvesting. Percent of water foxtail control with butachlor 0 and 5 days after rice harvesting was 85-89%. However, it dropped to 74-80% when applied 10 days after rice harvesting. In the thifensulfuron-methyl treatment, the dry matter of barley and wheat was 96-108% and 100-108%, respectively when compared with untreated control. While, in the butachlor treatment, the dry matter of barley and wheat was 53-73% and 106%, respectively when compared with untreated control. Therefore, we recommend thifensulfuron-methyl (75%) 0-10 days after rice harvesting or butachlor (5%) 5 days after rice harvesting to provide efficient water foxtail control and safe barley and wheat production.

• Korean Journal of Materials Research
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• v.9 no.7
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• pp.753-759
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• 1999

The microstructure and electrical properties of ZNR that W $O_3$ is added in the range 0.5~4.0mol%, were investigated. The major part of W $O_3$ were segregated at the nodal point and W-rich phase was formed. Three crystalline phases, such as W-rich phase (W $O_3$), Bi-rich phase (B $i_2$W $O_{6}$ ), and spinel phase (Z $n_{2.33}$S $b_{0.67}$ $O_4$) were confirmed to be co-existed at the nodal point The average grain size increased in the range 15.5~29.9$\mu\textrm{m}$ with increasing W $O_3$ additive content. Consequently. W $O_3$ acted as a promotion additive of grain growth. As the W $O_3$ additive content increases. the varistor voltage and the nonlinear exponent decreased in the range 186.82~35.87V/mm and 20.90~3.34, respectively, and the leakage current increased in the range of 22.39~83.01 uh. With increasing W $O_3$ additive content, the barrier height and the density of interface states decreased in the range 1.93~0.43eV and (4.38~1.22)$\times$10$^{12}$ $\textrm{cm}^2$, respectively. W $O_3$ acted as an acceptor additive due to the donor concentration increasing in the range (1.06~0.38)$\times$10$^{18}$ /㎤with increasing W $O_3$ additive content.t.t.

• Korean Journal of Weed Science
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• v.4 no.2
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• pp.163-168
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• 1984

This study was conducted to find out the effect of paclobutrazol 0.6G and flurprimido 50wp application at 40 days before heading on the characters related with lodging and the growth and yield of paddy rice plants in 1983. The culm length were shortened by paclobutrazol and flurprimido applications and high level of suppression was observed in the 3rd to 5th internodes. Paclobutrazol caused thiner internode and thicker wall of internode than the untreated control, however flurprimido caused thicker wall of internode without change of internode diameter. The breaking weight of lower internode was higher by flurprimido application than those by the untreated control and paclobutrazol application. The lodging indexes effected by both chemicals were remarkably decreased, and also the field lodging was not observed. The leaf area indexes effected by paclobutrazol and flurprimido applications were increased because of the increasing of tillers and green leaves per stem in spite of shortening of lead blades. Paclobutrazol and flurprimido application out-yielded significantly the untreated control lodged at grain filling stage. However in conditions of untreated with no lodging, the yields of these treatments were significantly less than that of untreated control.

• Weed & Turfgrass Science
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• v.2 no.3
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• pp.318-321
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• 2013

National Academy of Agricultural Science and eight province Agricultural Research & Extension Services investigated the occurring area of herbicide resistant weeds in paddy field of Korea. In order to estimate the occurring areas of herbicide resistant weeds, we collected paddy soils randomly from 3,200 sites in 2011 and 2012, and treated 30 kg $ha^{-1}$ of pyrazosulfuron-ethyl+pyriminobac-methyl GR to the paddy soil. 176,870 ha, approximately 22.1% of cultivated area excluding organic and eco-friendly cultivated area, was estimated to be infested by SUherbicide resistant paddy field weeds. Several species of resistant weeds were occurred at Jeonranam-do with 44.3%, followed by 30.5% at Chungchungnam-do, 27.8% at Chungchungbuk-do, and 24.5% at Jeonrabuk-do, respectively. Monochoria vaginalis showed the highest distribution with 57,018 ha, 32.2% followed by Scirpus juncoides, and Lindernia procumbens, respectively.

• Korean Journal of Weed Science
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• v.14 no.1
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• pp.28-33
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• 1994

This study was conducted to investigate the efficacy of weed control by pyributicarb{O-[3-tert-butylphenyl] N-[6-methoxy-2-pyridyl]-N-methyl thiocarbamate}/bensulfuron-methyl{methyl 2-[[[[[[4, 6-dimethoxypyrimidin-2-yl] amino] carbonyl] amino] sulfonyl] methyl] benzoate} SC and oxadiazon{5-tert-butyl-3-[2,4-dichloro-5-isopropoxyphenyl]-1,3,4-oxadiazol-2(3)-one}/bensulfuron-methyl SC, and to develope weed control methods for paddy rice. There was little difference between suspension concentrate and granule of pyributicarb/bensulfuron-methyl and oxadiazon/bensulfuron-methyl combination in the effect of weed control. Pyributicarb/bensulfuron-methyl SC and oxadiazon/bensulfuron-methyl SC were diffused from the point of application to 6m. Pyributicarb/bensulfuron-methyl SC applied on water surface from irrigation inlet and in paddy water from dike controlled more than 90% of weeds. Pyributicarb/bensulfuron-methyl SC was precipitated about 1-2cm per 1 hour after dripping on water surface. The efficacy of weed control by pyributicarb/bensulfuron-methyl SC was higher in 0-1cm than in 6-7cm standing water depth.

• Weed & Turfgrass Science
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• v.4 no.3
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• pp.151-158
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• 2015

This study was conducted to establish the effective weed management methods in rice field simultaneously dominated by the herbicide resistant Echinochloa oryzicola, Monochoria vaginalis and Scirpus juncoides. Herbicides registered for use before transplanting, oxadiazon 12% EC, pyrazolate 36% SC, pretilachlor 14% EC and thiobencarb 50% EC were effective until 0.5 leaf stage of herbicide resistant Echinochloa oryzoides. Herbicides registered for use after transplanting, fentrazamide 1% GR and mefenacet 18% SC were effective until 2 leaf stage of herbicide resistant Echinochloa oryzicola and triafamone 0.98% SC was possible to control up to 4 leaf stage. HPPD inhibitors, benzobicyclon, mesotrione and tefuryltrione SC, were simultaneously effective to SU herbicide-resistant Monochoria vaginalis and Scirpus juncoides. Herbicides registered for use before transplanting, benzobicyclon + oxadiargyl EC out of the tested herbicide was most effective in rice field simultaneously dominated by the herbicide resistant Echinochloa oryzicola, Monochoria vaginalis and Scirpus juncoides. Its effectiveness rises in proportion to flooding duration. Mazosulfuron GR, a herbicides registered for use after transplanting was most effective without phytotoxicity until 60 days after transplanting in rice field simultaneously dominated by the herbicide resistant Echinochloa oryzicola.