• Korean Journal of Weed Science
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• v.7 no.2
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• pp.179-185
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• 1987

Laboratory studies were conducted to evaluate safening effect of CGA 123'407 (4,6-dichloro-2-phenyl-pyrimidine) against pretilachlor, butachlor, and benthiocarb in rice plants. Butachlor and benthiocarb at 50 ppm or higher concentrations significantly inhibited rice growth and pretilachlor gradually inhibited growth of rice plants with increase in concentration starting from 0.5 ppm. CGA 123'407 at 0.1 ppm or higher concentrations was effective in reducing injury of rice plants when butachlor and benthiocarb were applied at rate of 10 ppm. Rice injury from pretilachlor at 10 ppm was also reduced by addition of CGA 123'407 at 0.25 ppm or higher concentrations Herbicidal activity of pretilachlor, butachlor, and benthiocarb was not affected by mixture treatments of CGA 123'407.

• Korean Journal of Weed Science
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• v.8 no.3
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• pp.237-243
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• 1988

Field study was conducted to evaluate safening effect of fenclorim (4,6-dichloro-2-phenyl pyrimidine) against benthiocarb, butachlor, and pretilachlor injury in rice plants under vinyl-covered subirrigated seedbed. Combinated application of benthiocarb 210, and 315 g ai/10a with fenclorim 10 g ai/10a or higher concentration, butachlor 180, and 270 g ai/10a with fenclorim 20 g ai/10a or higher concentration, and pretilachlor 60, and 90 g ai/10a with fenclorim 30 g ai/10a reduced herbicide injury of rice, and thus increased standing, plant height, tillers, and dry weight of rice plants compared to no combined application of fenclorim.

• Korean Journal of Weed Science
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• v.9 no.3
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• pp.214-220
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• 1989

The experiments were conducted to evaluate safening effect of fenclorim (CGA 123'407, 4,6-dichloro-2-phenyl pyrimidine) against injuries of pretilachlor, butachlor, and benthiocarb in direct-seeded rice under flooded conditions. Pretilachlor and butachlor and benthiocarb reduced crop standing and inhibited growth of rice plants. However, premixture application of pretilachlor, butachlor or benthiocarb with fenclorim at 10-30 g ai/10a greatly reduced rice injury caused by the application of each herbicide alone and thus increased crop standing plant height and dry weight of rice plants compared to herbicide treatments alone.

• Korean Journal of Weed Science
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• v.6 no.2
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• pp.99-101
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• 1986

• Korean Journal of Weed Science
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• v.6 no.2
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• pp.154-161
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• 1986

Since herbicide damage has been occurred in subirrigated rice seedbed in Korea, the use of crop safener is required to reduce crop injury. Field studies were conducted to evaluate safening effect of 1,8-naphthalic anhydride (NA) and CGA 123'407 (4, 6-dichloro-2-phenyl-pyrimidine) against four kinds of paddy herbicides applied to subirrigated vinyl-covered rice seedbed. NA as a seed dressing at 0.5% (W/W) was effective in reducing rice injury from butachlor, pretilachlor, chlormethoxynil and benthiocarb, and increased number of seedling established, plant height, and dry weight of rice seedlings, while growth inhibition and stand loss were observed at 1% NA. Pretilachlor slightly decreased number of seedlings established and inhibited growth of rice seedlings. But pre-mix combination of pretilachlor (2%) and CGA 123'407 (0.5%) reduced rice injury caused by pretilachlor alone and increased number of seedlings established and dry weight of rice seedlings. The results indicate that NA and CGA 123'407 would permit the safe application of butachlor, pretilachlor, chlormethoxynil, and benthiocarb in subirrigated rice seedbed.

• Korean Journal of Weed Science
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• v.8 no.1
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• pp.59-63
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• 1988

In order to select herbicides which may feasible to water-seeded rice culture, pot trial was initiated to determine phytotoxicity of rice plants to pyrazolate, bensulfuron methyl, chlormethoxynil, and benthiocarb under water-seeded condition. Pyraolate at 300 and 600 g ai/10a did not show crop injury and growth inhibition of rice plants. Bensulfuron methyl at 5.1 g ai/10a and benthiocarb at 210 g ai/10a were relatively safe to water-seeded rice plants when treated at 5 days after seeding. Chlormethoxynil at 210 g ai/10a showed crop injury and growth inhibition of rice plants and thus may not feasible to water-seeded rice culture.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.4
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• pp.287-292
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• 1981

The field studies were carried out in paddy field over a four year period in order to find out the effects of butachlor, nitrofen, oxadiazon or CG 102, benthiocarb-S, and bentazon applied successively to the same paddy field for four years on weed succession and rice yields under different fertilized conditions including compost, chemical fertilizer and straw application. Total dry weight of weeds was steadily increased yearly over 4 year period regardless of fertilized conditions, and significantly higher increase of weed dry weight was observed on non-fertilized and compost plots. The most dominant weed species was Scirpus hotarui, and Potamogeton distinctus, Eleocharis kuroguwai and Cyperus serotinus were predominated on compost plot, E. kuroguwai and E. aclularis on non-fertilized plot, E. kuroguwai, C. serotinus, and Monochoria vaginalis on chemical fertifizer plot, and C. serotinus on straw plot. When the same herbicides were used continuously on the same plots, weed control effect was decreased and thus weed population was greatly increased particularly on butachlor and nitrofen treated plots. P. distinctus, E. kuroguwai, and C. serotinus were predominated on butachlor treated plot, P. distinctus and C. serotinus on nitrofen treated plot, C. serotinus on benthiocarb-S treated plot, C. serotinus and P. distinctus on oxadiazon or CG 102 treated plot and P. distinctus on bentazon treated plot. Annual weeds were slightly increased by repeated annual application of oxadiazon or CG 102 and benthiocarb-S, whereas perennial weeds were predominated by successive application of butachlor, nitrofen. and bentazon for 4 years. Yield reduction of rice became prominent by successive application of same herbicides. particularly butachlor and nitrafen. This results suggested that successive annual application of same herbicides should be limited and herbicide combination or herbicide rotation should be applied to control the remaining weed species.

• Korean journal of applied entomology
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• v.15 no.4 s.29
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• pp.205-214
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• 1976

Effect of Butachlor(2-chloro-2, 6-diethyl N-(buthoxymethyl) acetanilide), Nitrofen(2,4-dichloro-4-nitrodiphenyl ether), Benthiocarb+Simetryne(s-(4-chlorobenzyl)-N, N-diethylthiocarbamate $7\%$+2-methylthio-4, 6-bis(ethylamino)-s-triazine $1.5\%)$, Propanil (3,4-dichloropropionanilide), and Perfluidone {1. 1. 1-trifluoro-N, N-(2-methyl-4-(phenylsulfonyl) Pheny1) methanesulfon amide} on urea hydrolysis and subsequent nitrification was investigated in a flooded soil incubated at $24\pm1^{\circ}C$ for 9 weeks. 1. Butachlor and Perfluidone at the rate of 1,440 and 1,200g, ai/10a, respectively, slightly inhibited the early stage of urea decomposition, and caused a slight decrease in the production of ammomium, which, however, was recovered readily. 2. Propanil at the rate of 2,800g, ai/10a imhibited the first stage of nitrification, and brought about a slight increase in the ammonium conentration and a decrease in the concentration of nitrite and nitrate. This inhibitive effect was a little more evident at higher concentration of applied nitrogen. The other herbicides caused no inhibition of urea decomposition and subsequent nitrification even at the highest rate of application. 3. pH and Eh of the soil were not significantly affected by the herbicides tested.

• 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 Weed Science
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• v.12 no.3
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• pp.271-291
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• 1992

This study was conducted to survey the situation of direct rice seeding in Honam province in Korea to investigate problems and seek countermeasure of weed control in direct rice seeding. The total area of direct rice seeding in the south-western part of Korea (Chonbuk, Chonnam, and Chungnam) was 1650.8ha (732.1ha for direct seeding in dry field and 918.7ha for direct seeding in flooding field) in 1992. The followings are summary of the study. 1. In case of direct rice seeding in dry field, butachlor EC and G at 3 to 5 DAS was mostly selected by farmers to control weeds in dry field. Benthiocarb or chlornitrofen was also used in few cases. At 10 to 14 DAS just before rice emergence, tank misture of butachlor EC and paraquat was treated by some farmers. At 35 to 40 days, after flooding mixture of sulfonylurea derivatives was sequentially applied. Surviving weeds including barnyardgrass were finally controlled by mixture of bentazon+quinclorac WP foliage application. 2. In case of direct rice seeding in flooding field, weed control were mostly unsuccessful partially due to wrong selection of herbicide and missing the optimum application time. Three relatively successful weed control in the survey were summarized as follows. 1) Oxadiazon EC, butachlor or benthiocarb were treated just after puddling(5 to 7 days before seeding). then mixture of bentazone+quinclorac WP or sulfonylurea derivatives was sequently applied to control remaining weeds at 20 days after seeding. 2) Mixtures of bensulfuronmethyl+dimepiperate G, pyrazosulfuronethyl+molinate G, or bensulfuronmethyl+mefenacet+dymron G were applied at 11 days after puddling when barnyardgrass were at 2.0 leaf stage. Phytotoxicity was not found in case of mixture of bensulfuronmethyl+dimepiperate G but found in the other two cases but disappeared later. 3) Mixtures of bensulfuronmethyl+quinclorac G., pyrazosulfuronethyl+quinclorac G or betazone and quinclorac G were treated after 18 to 20 days after puddling when barnyardgrass was within 3.0 leaf stage. It showed good weed control in both annuals and perrenials without phytotoxicity. On the contrary, other sulfonylurea derivatives such as middle periodic herbicide showed poor weed control against barnyardgrass, so that sequential treatment of bentazone+quinclorac WP mixture was required. 3. Herbicidal characteristics and optimum application time of 45 rigistered herbicides in Korea were analyzed to discover new substitute for quinclorac mixture, that showed excellent weed control against barnyardgrass at its 3 leaf stage or older. The analysis revealed that 70% of herbicides were for preemergence and the others were post periodic herbicide. Most farmers favor to apply herbicide when rice seedlings completely rooted, at this time barnyardgrass are at 2.5-3.0 leaf stage. Therefore herbicide of which optimum application time had long is required. In this study. 6 middle periodic herbicides among sulfonylurea derivatives and 2 quinclorac mixture were selected and evaluated their weeding spectrums at different leaf stage of barnyardgrass in both soil application in flooding condition and foliage application in dry paddy field. The order of weeding spectrum in magnitude was as follows : bentazone+quinclorac WP> bentazone + quinclorac G>bensulfuronmethyl + quinclorac G>pyrazosulfuronethyl + quinclorac G> pyrazosulfuronethyl + Molinate G>bensulfuronmethyl + mefenacet + dymron G>bensulfuronmethyl + mefenacet G>bensulfuron methyl+benthiocarb G. The above results coincided with that of the survey. In conclusion, there is no proper substitute for quinclorac mixrure, which can control barnyardgrass at 3.0 leaf stage or even older. Therefore quinclorac should be supplied continuously to farmers in order to anchor direct rice seeding in Korea. Author suggested the followings to eastablish direct rice seeding technology effectively and quickly : 1) A tentatively named "The research committee for direct rice seeding" which was composed of farmers. researchers and goberment. should be eastablished to cooperate effectively. 2) Development of a pricise direct rice seeding machine for both dry and flooding paddy field. which is workable regardless of condition and varieties of seeds. 3) Study on protecting rice seed and seedling from sparrows. 4) Systematic studies of weed control techniques in direct rice seeding to standardize herbicide application. 5) Studies on farm-land reformation. techniques of precise land preparation. and direct rice seeding using an airplane.