• Title, Summary, Keyword: pyribenzoxim

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Herbicidal Efficacy of Cyhalofop/Bentazon and Pyribenzoxim as Affected by Application Time in Dry - Seeded Rice (벼 건답직파시(乾畓直播時) 중후기(中後期) 경엽처리용(莖葉處理用) 제초제(除草劑)의 처리시기별(處理時期別) 잡초방제효과(雜草方劑效果))

  • Moon, Byeong-Chul;Park, Sung-Tae;Kim, Sang-Yeol;Kim, Soon-Chul;Oh, Yun-Jin
    • Korean Journal of Weed Science
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    • v.18 no.1
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    • pp.28-35
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    • 1998
  • Cyhalofop/bentazon ME and pyribenzoxim EC herbicides were originally developed as foliarapplied herbicides to control weeds at 4-5 leaf stages of barnyard grass 20-25 days after seeding (DAS) in direct-seeding culture but further possible utilization of these two herbicides earlier than 3-4 leaf stages of rice were evaluated for a field where early weed infestations might be severe. The application of cyhalofop/bentazon ME and pyribenzoxim EC at right after rice emergence and the 2-3 leaf stages of rice had an excellent weed control efficacy with above 90% up to 30 DAS without a phytotoxicity of rice plant and the control efficacy of over 80% was maintained until 60 DAS. However, these two herbicides controlled Echinochloa crus-galli very effectively above 97% but Aneilema keisak and Aeschynomene indica were not controlled by cyhalofop/bentazon ME and Cyperus serotinus by pyribenzoxim EC. Therefore, to control those problem weeds, second systematic application of pyribenzoxim EC and pyrazosulfuron/mefenacet G for A. keisak and A. indica, and pyrazosulfuron/molinate G, cyhalofap/ azimsulfuron/molinate G, pyrazosulfuron/mefenacet G and bentazon SL for C. serotinus at 30 DAS was found to be very efficient herbicide systems.

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Response of domestically collected Echinochloa species to cyhalofop-butyl and pyribenzoxim herbicides, their absorption and translocation (국내 피 수집종에 대한 cyhalofop-butyl과 pyribenzoxim의 약제반응 및 흡수이행)

  • Lee, In-Yong;Park, Jae-Eup;Park, Tae-Seon;Kim, Kil-Ung
    • The Korean Journal of Pesticide Science
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    • v.3 no.2
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    • pp.19-28
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    • 1999
  • To investigate the physiological and biochemical differences between susceptible and tolerant species of Echinochloa species to the foliar applied cyhalofop-butyl and pyribenzoxim herbicides, herbicidal response, the rate of absorption, translocation and metabolism were studied. Among 148 individuals of Echinochloa species collected from 41 sampling sites in Korea which were classified into 7 geographical regions, based on morphological characteristics of plant and seed type, 46 lines were used for further studies. From them, E. crus-galli var. praticola collected from Hwanggan and E. crus-galli var. crus-galli collected from Namyangju were selected as the most susceptible species to cyhalofop-butyl and pyribenzoxim, respectively. Meanwhile, E. oryzicola(from Cheju) and E. crus-galli var. crus-galli(from Asan) were selected as tolerant species to cyhalofop-butyl and pyribenzoxim, respectively. Application of radio-labelled herbicides on the 1st leaf to both susceptible and tolerant Echinochloa species exhibited that the applied $^{14}C$-Cyhalofop-butyl and $^{14}C$-pyribenzoxim were more easily absorbed and translocated into stem tissues than root. Absorption of $^{14}C$-Cyhalofop-butyl increased rapidly at 1 h after application and reached the maximum at 12 h after application. However, the absorption rate of $^{14}C$-pyribenzoxim was not changed. Two metabolites from cyhalofop-butyl-treated plants and one metabolite from pyribenzoxim-treated plants were separated by TLC. The amount of metabolite 1 in cyhalofop-butyl-treated tolerant species was significantly higher than that in the susceptible one, suggesting differences in detoxification ability between susceptible and tolerant species.

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Characterization of Pyribenzoxim Metabolizing Enzymes in Rat Liver Microsomes

  • Liu Kwang-Hyeon;Moon Joon-Kwan;Seo Jong-Su;Park Byeoung-Soo;Koo Suk-Jin;Lee Hye-Suk;Kim Jeong-Han
    • Toxicological Research
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    • v.22 no.1
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    • pp.1-8
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    • 2006
  • The primary metabolism of pyribenzoxim was studied in rat liver microsomes in order to identify the cytochrome P450 (CYP) isoform(s) and esterases involved in the metabolism of pyribenzoxim. Chemical inhibition using CYP isoform-selective inhibitors such as ${\alpha}$-naphthoflavone, tolbutamide, quinine, chlorzoxazone, troleandomycin, and undecynoic acid indicated that CYP1A and CYP2D are responsible for the oxidative metabolism of pyribenzoxim. And inhibitory studies using eserine, bis-nitrophenol phosphate, dibucaine, and mercuric chloride indicated pyribenzoxim hydrolysis involved in microsomal carboxylesterases containing an SH group (cysteine) at the active center.

Safening Activity of Optically Active ${\alpha}$-Methylbenzylphenylurea toward Bensulfuron-methyl and Pyribenzoxim Injury to Rice (광학활성 ${\alpha}$-Methylbenzylphenylurea 유도체의 bensulfuron-methyl과 pyribenzoxim의 벼에 대한 약해경감효과)

  • Ryoo, Jae-Hwan
    • The Korean Journal of Pesticide Science
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    • v.9 no.2
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    • pp.153-158
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    • 2005
  • Safening activities of optically active ${\alpha}$-methylbenzylphenylureas on crop injury of rice (Oryza sativa L., cv. Tsukinohikari, japonica) caused by bensulfuron-methyl (methyl 2-[[[[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]amino]sulfonyl]methyl]benzoate) and pyribenzoxim (benzophenone o-[2,6-bis[(4,6-dimethoxy-2-pyrimidinyl)oxy]benzoyl]oxime) were investigated. Some derivatives of the optically active compounds exhibited strong safening activity against growth inhibition of rice by bensulfuron-methyl. Out of the derivatives tested, (S)-2,3-diCl and (S)-2-F-4-Me derivatives showed greater relieving activity than that of dymuron. In addition, the stress relieving activity was also obtained when they were applied at 4 days after bensulfuron-methyl treatment. On the other hand, crop injury caused by pyribenzoxim was relieved by about 95% with (S)-2-F-4-Me derivative in shoots and roots of rice seedlings.

In vitro Metabolism of Pyribenzoxim

  • Kim, Ki Young;Kim, Jin;Liu, Kwang Hyeon;Lee, Hye-Suk;Kim, Jeong-Han
    • Journal of Applied Biological Chemistry
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    • v.43 no.1
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    • pp.49-53
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    • 2000
  • The in vitro metabolism of a new herbicide pyribenzoxim, {benzophenone O-[2,6-bis[(4,6-dimethoxy-2-pyrimidinyl)oxy]benzoyl]oxime} was studied using rice, barnyardgrass and rat liver microsomes. No metabolism of pyribenzoxim was observed with rice and barnyardgrass microsomes though the cvtochrome P450 was active, which was evidenced by the metabolism of cinnamic acid. With rat liver microsomes, four metabolites (M1, M2, M3, and M4) were produced while parent compound decreased. M1 and M2 were from the hydrolysis reactions and NADPH-dependent metabolites were M3 and M4 (major metabolite) which were hydroxylated by cytochrome P450. They were identified as bispyribac-sodium (M1), benzophenone oxime (M2), {benzophenone O-[2,6-bis[(5-hydroxy-4,6-dimethoxy-2-pyrimidinyl)oxy]-benzoyl]oxime}(M3), and {benzophenone O-[2[(5-hydroxy-4,6-dimethoxy-2l-pyrimidinyl)6-(4,.6dimethoxy-2-pyrimidinyl)oxy]benzoyl]oxime} (M4) through LC/MS/MS analyses. Based on the results obtained metabolic map of pyribenzoxim is proposed.

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Studies on Effect and its Mechanism of Herbicide Mixture of Cyhalofop-butyl, pyribenzoxim and Pyrazosulfuron-ethyl - II. Effect of Herbicide Mixture on the Activity of ALS, Content of Free Amino Acids and Fatty Acids (Cyhalofop-butyl, Pyribenzoxim 및 Pyrazosulfuron-ethyl의 상호작용효과(相互作用效果) 및 상호작용(相互作用) 기작(機作)에 관(關)하여 - 제(第) 2 보(報) 혼합제초제(混合除草劑) 처리(處理)가 acetolactate synthase 활성(活性) 및 유리(遊離) 아미노산함량(含量)과 지방산함량(脂肪酸含量)에 미치는 영향(影響))

  • Wu, Ming-Gen;Kim, Kil-Ung;Shin, Dong-Hyun
    • Korean Journal of Weed Science
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    • v.18 no.3
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    • pp.197-204
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    • 1998
  • This study was conducted to determine the activity of ALS, content of endogenous free amino acids and fatty acids affected by herbicide mixture of cyhalofop-butyl, pyribenzoxim and pyrazosulfuron-ethyl. $I_{50}$ values (concentration required for 50% inhibition of ALS activity) of pyribenzoxim herbicide on the activity of ALS in Echinochloa crus-galli and Cyperus serotinus in vitro were recorded at 4${\times}$100 nM and 5${\times}$10 nM, respectively, while $I_{50}$ values of pyrazosulfuron against E crus-galli and C. serotinus were 4.5${\times}$10 nM and 4${\times}$10 nM, respectively, and the mixture of two herbicides showed additive effect on ALS activity at the low application rate, and independent effect at the high application rates of two herbicides. The inhibition rates of the three herbicides mixture treatment on the three branch-chain amino acids such as valine, leucine and isoleucine were 74.6%, 66.6% and 57.9% in C. serotinus and 36.6% 51.1% and 48.1% in E. crus-galli, respectively. A little bit higher inhibitory effect on the three branch-chain amino acids in C. serotinus and E. crus-galli seedlings was observed in two herbicide mixture of pyribenzoxim with pyrazosulfuron than three herbicide mixture of cyhalofop with pyribenzoxim and pyrazosulfuron. The interaction among three herbicides showed non-antagonism on the amounts of endogenous free amino acids.

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Foliar Retention of the Herbicide Pyribenzoxim(1% EC), and Its Effects on Herbicidal Activity and Rice Phytotoxicity (Pyribenzoxim 1% 유제(乳劑)의 경엽(莖葉) 부착량(附着量)과 약효(藥效), 약해(藥害)의 관계(關係))

  • Koo, Suk-Jin;Kim, Jeong-Su;Lee, Jae-Hwan
    • Korean Journal of Weed Science
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    • v.18 no.4
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    • pp.304-313
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    • 1998
  • Foliar retention of pyribenzoxim (1% EC) was measured using the fluorescent dye rhodamine B, and related to efficacy and phytotoxicity to barnyardgarss (Echinochloa crusgalli) and rice (Oryza sativa cv. Chucheong), respectively. Effects of nozzle types (8002E flat-fan and disk-type), addition of adjuvant, variation of herbicide concentration or spray volume were compared. In barnyardgrass, foliar retention of pyribenzoxim at a recommended condition (application rate : 30g ai/ha, spray volume : 1000 L/ha) was 2.3 to 2.7 or 1.4 to $1.5{\mu}g$ ai/g fresh foliage when sprayed using the disk-type nozzle with or without adjuvant, respectively, and 0.6 to 0.7 or 0.3 to $0.5{\mu}g$ ai/g fresh foliage when sprayed using the flat-fan nozzle with or without adjuvant, respectively. The slope of increase in foliar retention was 1.0 to 1.8 when application rates increased from 10 to 60g ai/ha at 1000 L/ha, while that was 1.6 to 2.4 when spray volume increased from 330 to 2000 L/ha at $30{\mu}g$ ai/L concentration. Foliar retention of pyribenzoxim had a close relationship with herbicidal activity; regardless of spray conditions, retention to provide 90% control was about $0.8{\mu}g$ ai/g fresh foliage, and below this retention amount, efficacy decreased almost linearly. In rice, foliar retention at the recommended condition was 1.9 to 2.3 or 1.2 to $1.3{\mu}g$ ai/g fresh foliage when sprayed using the disk-type nozzle with or without adjuvant, respectively, and 0.6 to 0.9 or $0.3{\mu}g$ ai/g fresh foliage when sprayed using the flat-fan nozzle with or without adjuvant, respectively. The slope of increase in foliar retention was 1.0 to 2.8 when application rates increased from 30 to 120g ai/ha at 1000 L/ha, while that was 1.3 to 4.4 when spray volume increased from 1000 to 4000 L/ha at $30{\mu}g$ ai/L concentration. Despite the great difference in retention, rice phytotoxicity was not observed in any of these spray conditions, suggesting retention differences within 4-fold increase of application rate or spray volume do not affect rice safety. When pyribenzoxim 1EC was sprayed in tank-mix with several other commercial pesticide formulations, its retention to rice foliage tended to increase by 30 to 50%.

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In vitro Acetolactate Synthase Inhibition of LGC-40863 in Rice and Barnyardgrass (시규제초제 LGC-40863의 벼와 피에 대한 Acetolactate synthase 저해 활성)

  • Bae, Y.T.;Lee, J.H.;Koo, S.J.
    • Korean Journal of Weed Science
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    • v.17 no.1
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    • pp.66-70
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    • 1997
  • LGC-40863(proposed common name ; pyribenzoxim), (benzophenone O-[2,6-bis[(4,6-dimethoxy-2-pyrimidinyl)oxy]benzoyl]oxime) is a new rice herbicide being developed by LG Chemical Ltd. The herbicide is highly selective between rice(Oryza sativa L.) and weeds including barnyardgrass (Echinochloa crus-galli(L.) P. Beauv.), and assumed to inhibit acetolactate synthase(ALS ; EC 4.1.3.18) because other structurally related herbicides inhibit the enzyme. To know inhibitory activity and the mode of inhibition of LGC-40863, $I_{50}$(concentration inhibiting ALS activity by 50%) and inhibition kinetics were investigated using ALS extracted from rice and barnyardgrass. $I_{50}$ values of LGC-40863 were 14 and 16mM in rice and barnyardgrass, respectively. In contrast to imazapyr(2-[4,5-dihydro-4-mythyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-pyridine-carboxylic acid) which showed an uncompetitive inhibition pattern, LGC-40863 was a noncompetitive inhibitor to ALS with respect to pyruvate similar to chlorsulfuron(2-chloro-N-((4-methoxy-6-methyl-l,3,5-triazin-2-yl) aminocarbonyl)benz-enesulfonamide) in both plants.

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