• Korean Journal of Agricultural Science
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• v.40 no.3
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• pp.183-189
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• 2013

This study was conducted to evaluate the efficacy of herbicide mixtures of benzobicyclon and carfentrazone-ethyl in direct-seeding flooded rice. The efficacy of benzobicyclon mixtures and carfentrazone-ethyl mixtures was greater than that of pyrazosolfuron-ethyl + pyriminobac-methyl GR. Herbicide mixtures with benzobicyclon controlled average 97% and herbicide mixtures with carfentrazone-ethyl controlled average 95% 60 days after application. When compared with untreated control, no visual injuries were detected at single and double dosage of herbicide mixtures. The yield of rice increased in both benzobicyclon and carfentrazone-ethyl treatments when compared with pyrazosolfuron-ethyl + pyriminobac-methyl GR. Based on these data, combinations of these herbicides can be applied to provide effective weed management in rice field.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.4
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• pp.328-334
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• 2002

A Lindernia dubia (L.) Pennell var. dubia accession from Jeonnam province, Korea was tested for resistance to sulfonylurea (SU) herbicides, imazosulfuron and pyrazosulfuron-ethyl in whole-plant response bioassay. The accession was confirmed resistant to both herbicides. The $GR_{50}$ (herbicide concentration that reduced shoot dry weight by 50%) values of resistant accession were 264 and 19 times higher to imazosulfuron and pyrazosulfuronethyl, respectively, than that of the standard susceptible accession. The surviving resistant L. dubia after pyrazosulfuron-ethyl + molinate application can be controlled by sequential applications of soil-applied herbicides, butachlor, dithiopyr, pyrazolate, and thiobencarb and foliar herbicides, bentazon. Sulfonylurea-based mixtures such as mixtures of azimsulfuron + anilofos, bensulfuron-methyl + oxadiazon, pyrazosulfuron-ethyl + fentrazamide, and pyrazosulfuron-ethyl + anilofos + carfentrazon can also be used to control the surviving resistant L. dubia. However, use of these mixtures should be restricted to a special need basis. Thus, we suggest that sequential applications of non-SU-based mixtures such as butachlor + pyrazolate and MCPB + molinate + simetryne be used to control the surviving resistant L. dubia after SU herbicide applications. Rice yield was reduced 24 % by resistant L. dubia that survived after the pyrazosulfuron-ethyl + molinate application compared with pyrazolate + butachlor in transplanted rice culture. In vitro ALS activity of the resistant biotype was 40 and 30 times more resistant to imazosulfuron and pyrazosulfuron-ethyl, respectively, than the susceptible biotype. Result of in vitro ALS assay that the resistance mechanism of L. dubia to SU herbicides may be due, in part, to an alteration in the target enzyme, ALS.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.4
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• pp.286-291
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• 2003

Monochoria vaginalis is one of the most troublesome resistant weeds in Korean rice culture. Thus, the objectives of this study were to evaluate the response of M. vaginalis resistant to sulfonylurea(SU) herbicides and to determine alternative herbicides for the control of resistant M. vaginalis in direct seeded and transplanted rice culture in Korea. In greenhouse studies, the resistant biotype was 31-, 38-, 3172-, and 7-fold more resistant to ben-sulfuron-methyl, cyclosulfamuron, imazosulfuron, and pyrazosulfuron-ethyl, respectively, than the susceptible biotype, indicating cross-resistance to the SU herbicides used in this study. Non-SU herbicides, butachlor, carfentrazone-ethyl, mefenacet, pretilachlor, pyrazolate, and thiobencarb, several SU herbicide-based mixtures, ethoxysulfuron plus fentrazamide, pyrazosulfuron-ethyl plus pyrazolate plus simetryn, and non-SU herbicide-based mixtures, pyrazolate plus butachlor, pyrazolate plus pretilachlor, simetryn plus molinate, carfentrazone-ethyl plus butachlor, and carfentrazone-ethyl plus thiobencarb can be used to control both the resistant and susceptible biotypes of M. vaginalis when applied before the second leaf stage. In the field experiment, the resistant biotype of M. vaginalis that survived from the paddy fields treated with a SU herbicide-based mixture could effectively be controlled by using mixtures of bentazone plus MCPA, bentazone plus mecoprop-P, and bentazone plus 2,4-D when applied at 2 or 4 main leaves. Our results suggest that the SU-resistant M. vaginalis had not developed multiple resistances to herbicides with different modes of action. In particular, bentazone plus MCPA and bentazone plus mecoprop-P were effective control measures after failure to control resistant M. vaginalis in Korean rice culture.

• Weed & Turfgrass Science
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• v.3 no.3
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• pp.165-173
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• 2014

This review study was conducted to recommend the effective use of herbicide mixtures in Korea. The herbicide ingredients by Herbicide Resistancce Action Committee (HRAC) was classified into 23 groupes according to the mode of action (acetyl CoA carboxylase inhibitors, acetolactate synthase, photosystem I and II inhibitors, protoporphyrinogen oxidase inhibitors, carotenoid biosynthesis inhibitors, enolpyruvyl shikimate-3-phosphate synthase inhibitors, glutamine synthetase inhibitors, dihydropteroate synthetase inhibitors, mitosis inhibitors, cellulose inhibitors, oxidative phosphorylation uncouplers, fatty acid and lipid biosynthesis inhibitors, synthetic auxins, auxin transport inhibitors and potential nucleic acid inhibitors or non-descript mode of action). The rice herbicide mixtures registered in Korea were classified based on the guideline of HRAC. Accordingly, such a classification system for resistance management can help to avoid continuous use of the herbicide having the same mode of action in the same field.

• Korean Journal of Agricultural Science
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• v.41 no.2
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• pp.113-117
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• 2014

This study was conducted to evaluate the efficacy of benzobicyclon mixtures by using Remote-controlled aerial application (RCAA) to control annual and perennial weeds in rice paddy field. Eight annual weed species including Echinochloa crus-galli L. and three perennial weeds were dominated in the experimental field. Application of benzobicyclon mixtures using RCAA was highly effective to control both annual and perennial weed species. When compared with untreated control, no visual injuries were detected at single and double dosage of benzobicyclon mixtures. Finally, rice yield in the benzobicyclon mixtures was as much as that in the hand weeding. This study indicates that benzobicyclon mixtures using RCAA can be applied to control both annual and perennial weed species in rice paddy field.

• Korean Journal of Weed Science
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• v.18 no.2
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• pp.154-160
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• 1998

This study was conducted to develop a foliar applied herbicide mixture covering wide spectrum weeds in dry direct seeded rice. Uniform precision central composite design(UPCCD) was employed to evaluate the effect of herbicide mixture among cyhalofop-butyl(cyhalofop), bispyribenzoxim and pyrazosulfuron-ethyl(pyrazosulfuron) having different weed control spectrum and to determine the best application rates of the three herbicide mixtures. The partial additive effect was observed in the mixture of cyhalofop and bispyribenzoxim with pyrazosulfron against Echinochloa crus-galli Beauv var crus-galli L., attributed to the negative interaction between cyhalofop and bispyribenzoxim system. Additive effect was observed in the mixture of bispyribenzoxim and pyrazosulfuron against Cyperus serotinus R. and Aneilema keisak H. but cyhalofop had no effect on these weeds. The most appropriate rate of the mixture of cyhalofop with bispyribenzoxim and pyrazosulfuron was 100 : 12 : 10g ai/ha exhibiting $ED_{90}$ against three weeds such as E. crus-galli, C. serotinus and A. keisak.

• Korean Journal of Agricultural Science
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• v.42 no.2
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• pp.87-92
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• 2015

This study was conducted to evaluate the herbicidal efficacy of carfentrazone-ethyl mixtures in direct-seeding flooded rice. The efficacy of three different carfentrazone-ethly mixtures was greater than pyrazosulfuron-ethyl pyriminobac-methyl GR (PP GR). Weeding efficacy of three different carfentrazone-ethly mixtures was more than 96.9%. No phytotoxic effect was observed in the rice based on the plant height and the number of tillers. Yield of rice un three different carfentrazone-ethly mixtures application was more than both in the PP GR and in the hand weeding. Based on these data, three different carfentrazone-ethly mixtures can be applied to provide an effective weed management in direct-seeding flooded rice.

• The Korean Journal of Pesticide Science
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• v.8 no.1
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• pp.63-70
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• 2004

Sulfonylurea(SU)-resistant Monochoria korsakowii has resently been found in rice fields in Korea. A quick, practical and accurate test of confirming herbicide resistance is necessary to take timely management decision. This article describes a rapid reliable assay to detect SU-resistant biotype of Monochoria korsakowii. Up to now, the resistance to SU has been usually checked by application seedlings with herbicide. This application technique is time consuming and not practical. Therefore, we have developed efficient, rapid and practical diagnosis which allow easy detection of the SU-resistant Monochoria korsakowii by survival rate and regenerated plant length to herbicide application after cutting plants $0.5\sim1cm$ from the planted surface. This new rapid diagnosis can determine the SU resistance of the Monochoria korsakowii within 7 days at least. If the resistance of Monochoria korsakowii is identified by the rapid diagnosis, the selection of herbicide according to the stages of plants for the effective control is very important. The resistant biotype which treated with SU herbicide-based mixtures survived from the fields could effectively be controlled by soil application of butachlor+pyrazolate GR or by foliar application of the mixtures of bentazone SL and 2,4-D SL.

• Korean Journal of Weed Science
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• v.2 no.2
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• pp.146-151
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• 1982

Herbicide mixtures, butachlor + naproanilide, CG113 + naproanilide and benthiocarb + naproanilide were tested in order to control Sagittaria pygmaea Miq., one of the most serious perennial weeds in paddy field of Honam area. 92% of tuber of Sagittaria pygmaea Miq. was distributed within 9cm from the soil surface and number of emerged Sagittaria pygmaea Miq. increased until 40 days after rice transplanting but decreased thereafter. Number and dry weight of survived Sagittaria pygmaea Miq. were much less in butachlor + naproanilide, CG 113 + naproanilide and benthiocarb + naproanilide treatments than perfluidone and it was controlled by up to 95% by mixture treatments. Number of rhizome of Sagittaria pygmaea Miq. was decreased by all herbicide treatments and especially mixture treatment significantly reduced rhizome formation compared to perfluidone and 2.4 -D treatments. CG113 + naproanilide treatment caused phytotoxicity that tip of leaf sticked to leaf sheath curvedly in Indica ${\times}$ Japonica rice, Iri 358, but it was recovered within 10 days after herbicide treatment.

• Korean Journal of Environmental Agriculture
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• v.25 no.3
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• pp.262-267
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• 2006

Increased application of glyphosate (Gly) in glyphosate-resistant (GR) soybean cropping systems may affect rhizospheric microorganisms including IAA-producing rhizobacteria (IPR) and their effect on the growth of soybean. This field experiment was conducted to assess IPR populations in the rhizosphere of GR soybean ('Roundup-Ready' DeKalb DKB38-52) treated with glyphosate and foliar amendment treatments such as $PT21^{(R)}$ (urea solution with N 21 %) and $Grozyme^{(R)}$ (Biostimulant: mixtures of micro nutrients and enzymes). Effects of herbicide, sampling date, and their interaction on total bacterial numbers were significant (P < 0.001, 0.001, 0.013, respectively). Total bacteria (TB) numbers were increased with glyphosate treatment at 20 d after application and highest TB populations were associated with $Grozyme^{(R)}$ application, possibly due to the additional substrate from this product. The IPR of the soybean rhizosphere was significantly affected by herbicide, sampling date, and the herbicide*foliar amendment interaction. The ratios of numbers of IPR to TB ranged from 0.79 to 0.99 across the sampling dates irrespective of treatments. IPR numbers were slightly hindered by glyphosate application regardless of foliar amendment.