• Korean Journal of Weed Science
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• v.16 no.2
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• pp.132-139
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• 1996

Acetolactate synthase(ALS) activity was determined in germinating seedlings of two rice cultivars treated with cinosulfuron [3-(4,6-dimethoxy-1,3,5-triazin-2-yl)-1-[2-methoxyethoxy)-phenylsulfonyl]-urea]. IR 74(Indica type) was more tolerant than Hwajinbyeo(Japonica type) under various rates of cinosulfuron applied at the pregermination stage. In vitro response of ALS activity in the two rice cultivars was similar to $I_{50}$ values(cinosulfuron concentration required for 50% inhibition of ALS activity) of about 23ppb. In vivo, ALS activity of IR 74 increased as the seedlings grew, but that of Hwajinbyeo dropped at 5 days after 10ppm cinosulfuron treatment and shoot growth of Hwajinbyeo lagged at 4 to 5 days after herbicide treatment. ALS activity and shoot growth of Hwajinbyeo was resumed from cinosulfuron-induced inhibition at 6 days after cinosulfuron treatment. The differential response of ALS activity in two different rice cultivars against cinosulfuron may not be due to difference of ALS sensitivity, but rather due to different metabolic inactivation rates of cinosulfuron.

• Korean Journal of Weed Science
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• v.12 no.2
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• pp.110-123
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• 1992

To investigate the safening effect of dymron against cinosulfuron, the responses of 104 rice cultivars and lines to single and mixture treatments of cinosulfuron [3-(4.6-dimethoxy-1,3,5-triazin-2-yl)-1-[2-(2-methoxyethoxy)-phenylsulfonyl]-urea] and dymron [1-(${\alpha}$, ${\alpha}$-dimethylbenzyl)-3-p-tolyl urea] were evaluated. The responses of 104 rice cultivars and lines to cinosulfuron were differed. Among the rice cultivars, growth of Calrose, Dasukei, Hwajinhyeo, and Milyang 105 was significantly inhibited by cinosulfuron but there was no inhibition in Daeseongbyeo, Iri 371, Jangseongbyeo, Taebaegbyeo and IR 74. The japonica types were generally inhibited more than the indica and indica${\times}$japonica types. When Kwangmyungbyeo was treated with the mixtures of cinosulfuron 48g and 96g ai/ha with dymron 450g ai/ha, the inhibition of plant height was significantly reduced regardless of dymron concentrations. With increase in cinosulfuron concentration, the safening effect of dymron against cinosulfuron was more evident in plant height than fresh weight. On the other hand, dymron did not have any safening effects of cinosulfuron on Echinochloa crus-galli at any concentrations. The mixtures of dymron and cinosulfuron produced antagonistic effects on the plant height regardless of rice cultivars and treatment concentrations. At cinosulfuron 24g ai/ha, the effects of the mixtures of cinosulfuron and brassinolide on the plant height of Kwangmyungbyeo and IR 74 were similar irrespective of brassinolide concentrations but the inhibition of Kwangmyungbyeo was greater than that of IR 74 as the concentrations of cinosulfuron increased. The effects of the mixtures of cinosulfuron at concentration of 96g ai/ha with various ABA levels on the plant height of both Kwangmyungbyeo and IR 74 showed synergistic effect regardless of ABA concentration. However, the response of fresh weight of both cultivars treated with cinosulfuron at 96g ai/ha with ABA synergisism was observed in Kwangyungbyeo while IR 74 showed antagonism.

• Korean Journal of Weed Science
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• v.14 no.4
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• pp.272-279
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• 1994

In order to compare the biological properties of benfuresate and cinosulfuron as herbicides for the chemical control of Eleocharis kuroguwai, some experiments were conducted at greenhouse and field conditions in 1993. Benfuresate and cinosufuron moved to 2cm and 6cm deep in paddy soil and inhibited the growth of E. kuroguwai. Benfuresate was absorbed into the roots of E. kuroguwai. whereas cinosulfuron was absorbed into not only the roots and shoots but also the mesocotyls. After the emergence was inhibited by the soil application of herbicides, the percentage of regrowing numbers was higher at cinosulfuron than at benfuresate, whereas the growth rate was higher at benfuresate on the contrary. Benfuresate brought about complete death of buds as a killing type, but cinosulfuron produced lots of abnormal shoots as an inhibiting type. Benfuresate was able to apply on soil surface from the preemergence to the early stage of 2cm high, but cinosulfuron was able to use from the preemergence to the stage of 15cm high. The foliar application of cinosulfuron showed a good control effect, but it induced a severe phytotoxicity to rice. A good control effect of Benfuresate/bensulfuron GR lowered at the late stage, but that of cinosulfuron/mefenacet/dymron GR at the early stage maintained until the late stage of 65 days after transplanting.

• Korean Journal of Weed Science
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• v.14 no.2
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• pp.112-119
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• 1994

The experiment was conducted to investigate the cause of the continous increase of Sagittaria trifolia dominance and it's effective control methods in the paddy rice fields. Early physilogical response of S. trifolia caused by sulfonylurea three herbicides resulted in growth cessation. However, the growth-ceased plant regrew after the certain period of time. Pyrazolate{4-[2, 4-dichloro benzoyl]-1, 3-dimethylpyrazol-5-yl-ptoluene sulphonate} could control S. trifolia until 6-7 leaf stages. The herbicidal activity of S. trifolia by pyrazolate was not related to the size of tuber and the amount of carbohydrate consumption in the tuber. The production of S. trifolia tubers inhibited more than 95% by the systematic treatment of pyrazosulfuron-ethyl{Ethyl-5-(4, 6-dimethoxy pyrimidin-2-yl carbomoyl sulfamoyl)-2-chloro-2', 6'-diethyl acetanilide}, cinosulfuron and pyrazolate after the first treatment of pyrazosulfuron-ethyl and pyrazolate.

• The Korean Journal of Pesticide Science
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• v.2 no.2
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• pp.119-125
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• 1998

A nation-wide fact-finding survey was done to provide the basic information for establishing the rational weed control scheme in paddy rice. A total of 445 respondents including 273 farmers and 172 pesticide dealers was involved in this survey. Dominant weeds in rice paddy field were Echinochloa crus-galli, Eleocharis kuroguwai, Sagittaria pygmaea, Sagittaria trifolia, etc.. Preferred herbicides widely used by farmners were ranked in the following order; butachlor 5GR, pyrazosulfuron-ethyl + molinate 5.07GR, molinate + cinosulfuron 5.08GR, meanwhile, those recommended by pesticide dealers were; pyrazosulfuron-ethyl + molinate 5.07GR, molinate + cinosulfuron 5.08GR, and butachlor 5GR. The guidelines to choose the preferred herbicides was primarily based on the experience, which was occupied about 45%. Approximately 56% of the farmers followed the recommended herbicide dosage and 43% of them applied the herbicides before weed germination (pre-emergence treatment). In addition, most farmers applied herbicides at least two times with systematic application schedule. Application method of granular formulation was broadcasting by hand, while that of sprayable ones was by high-pressure sprayer. Some farmers answered that they had experienced phytotoxicity in the crop by applied herbicides, of which higher experience was observed from the farmers who applied by high-pressure sprayer. It was analyzed significantly that the feasible herbicides to cause phytotoxicity in rice at farmer's level were butachlor 5GR, esprocarb + pyrazosulfuron-ethyl 5.07GR and bensulfuron-methyl + molinate 5.17 GR.

• The Korean Journal of Pesticide Science
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• v.8 no.4
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• pp.332-337
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• 2004

A suspected biotype of Scirpus planiculmis to be resistant to sulfonylurea(SU) herbicides was identified in Seosan reclaimed paddy fields in Korea, in 2004. The fields have been cultivated for monocultural rice production with wet-direct seeding method and continuously treated with SU-based herbicide mixtures for thirteen years since 1990. In greenhouse studies, 6 different SU herbicides, such as azimsulfuron, bensulfuron-methyl, cinosulfuron, ethoxysulfuron imazosulfuron and pyrazosulfuron-ethyl, completely controlled the Musan assession of Scirpus planiculmis at the recommended dose of each herbicide, however, the Seosan accession of S. planiculmis biotype was survived 20 to 45% even treated with 5 times higher dose of each recommended rate of all herbicides treated. The $GR_{50}$ values of 6 SU herbicides for Seosan accession of S. planiculmis were 47 to 100 times higher than those for Musan accession of S. planiculmis. The $I_{50}$ values pyrazosulfuron-ethyl to acetolactate synthase(ALS) extracted from Sesan and Muan accession of S. planiculmis were 409 nM and 0.8 nM, respectively. The $I_{50}$ value of Seosan was 511 times higher than that of Muan accession. These results suggested that the Seosan accession of S. planiculmis have strong resistant characteristics to 6 SU herbicides, respectively, indicating that resistance might be due to the alteration in the target site of ALS.

• Korean Journal of Weed Science
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• v.15 no.2
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• pp.99-104
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• 1995

This experiment was conducted to evaluate effective weed control in direct-seeded rice under dry fields. The results obtained are as follows. Cyhalofop/bentazone EW and cyhalofop/pendimethalin EC were very effective for the weed control but cyhalofop/cinosulfuron WP and cyhalofop/azimsulfuron SC were tended to exhibit the lower weeding effect. The plant height and the tiller number of rice were not greatly affected by herbicides, but rice yield was greatly influenced by them. The control efficacy was observed the extend of 94% until 60days after seeding under the treatment of systematic herbicides such as foliar applied pendimethalin propanil EC at 15days after seeding mowed by pyrazosulfuron molinate GR at 5days after irrigation. Irrigation at 25days after seeding was able to control annual weeds by the extent of 25% and exhibited control effect of 94% on systematic treatment of herbicides compared with that of 35days after seeding.