• Korean Journal of Weed Science
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• v.17 no.1
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• pp.24-30
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• 1997

The influence of nutrients on the phytotoxicity of herbicides (bensulfuron-methyl, pyrazosulfuron-ethyl, imazosulfuron, dimepiperate, and molinate) was investigated in controlled-environment growth chamber with direct-seeded rice (Oryza sativa L. cv. Dongjin). The phytotoxicity of bensulfuron-methyl, pyrazosulfuron-ethyl, and imazosulfuron for rice was greater in nutrient culture than in no-nutrient condition. The root growth of rice applied with these herbicides was more inhibited than the shoot growth. The most severe inhibition was obtained with pyrazosulfuron-ethyl application. The growth inhibition of rice applied by dimepiperate was increased under no-nutrient culture condition. Dimepiperate suppressed more remarkably shoot growth than root. Especially the shoot elongation was much more inhibited than the others. The shoot growth inhibition in rice applied by molinate was severer than the root. The shoot growth was reduced under nutrient culture condition, while the root growth was reduced under no-nutrient culture.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.4
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• pp.387-392
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• 2007

The effect of mixed treatments of wood vinegar and sulfonylurea-based herbicides on weed control, yield and yield components, and quality of rice was investigated. Two herbicides were tested namely: imazosulfuron-ethyl+thiobencarb[ethyl-1-(2-chloroimidazo[1,2-$\alpha$]pyridin-3-ylsulfonyl)-3-(4,6-dimethoxypyrimidin-2-yl) urea+S-4-chlorobenzyl diethyl(thiocarbamate)], and bensulfuronmethyl+butachlor [methyl $\alpha$-[(4,6-dimethoxypyrimidin-2-ylcarbamoyl)sulfamoyl]-o-toluate+N-butoxymethyl-2-chloro-2',6'-diethylacetanilide]. The experiment was carried out in a randomized complete block design with 3 replications and 5 treatments. Treatments used were recommended(RH: 100%) and half-recommended(HRH: 50%) application rates of each herbicide. Half-recommended application rates were combined with 1 mL wood vinegar $500mL\;water^{-1}$(500) and 1 mL wood vinegar $1000mL\;water^{-1}$(1000) wood vinegar. Plots for no herbicide treatments were also prepared and used as control. Results showed that wood vinegar significantly increased efficacy of HRH in bensulfuron-methyl+butachlor while high efficacy was already obtained in HRH treatment of imazosulfuron-ethyl+thiobencarb. Wood vinegar did not improve the efficacy of imazosulfuron-ethyl+thiobencarb but improved rice yield. Significantly similar rice yields were obtained in the HRH+1000 WV and RH treatments of both herbicides. There were no significant variations in the yield components among the treatments; however, differences in yield can be attributed to the variations in the spikelet number and ripening ratio. Data on rice quality analysis did not show clear trend on the effects of the treatments on grain appearance and nutritional quality.

• Korean Journal of Environmental Agriculture
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• v.42 no.1
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• pp.63-70
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• 2023

Golden apple snails (Pomacea canaliculat) (GAS) are widely used for weed control in rice cultivation. However, concerns on the ecological risk of invasive GAS species are increasing. This study aimed to evaluate the overall impacts of GAS on weed control, abundance of aquatic animals and insects, and rice yield, in comparison with that from other biocontrol agents such as loach (Misgurnus mizolepis) and catfish (Silurus asotus), which are alternatives for biological weed control in rice paddy cultivation. Field experiments included five treatments; control, herbicide, GAS, loach, and catfish. During the rice growth, weed appearance and biological abundance were monitored, and at harvest, the rice yield was determined. Weed control efficiency was the highest for GAS treatment (100%), followed by that for herbicide (95.8%), loach (57.5%), and catfish treatments (31.7%). Insect abundance was considerably decreased in GAS treatment due to heavy weed removal, which affects the habitat of aquatic animals and insects. The amount of rice yield (unit: kg 10 a^-1) was in the order of GAS (798.9) > loach (708.1) = herbicide (700.7) > catfish (629.4) > control (496.0). Therefore, considering the weed control efficiency, biological abudance, and rice yield, loach could be a potential alternative for biological weed control in organic rice farming. However, the activity of the biocontrol agents are susceptible to environmental conditions; therefore, further studies under different conditions are essential to confirm these findings.

• Korean Journal of Weed Science
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• v.30 no.3
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• pp.225-232
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• 2010

The effect of Protox expression site on herbicidal resistance was investigated in wild-type and transgenic rice plants imposed by peroxidizing herbicide oxyfluorfen. The transgenic rice systems involved the plastidal expression of Arabidopsis protoporphyrinogen oxidase (Protox; AP line) and the dual expression of Myxococcus xanthus Protox in chloroplasts and mitochondria (TTS line). The oxyfluorfen-treated TTS4 line showed the lower levels of cellular leakage and malonyldialdehyde and the sustained capacity of 5-aminolevulinic acid synthesis, compared to the oxyfluorfen-treated AP and wild-type lines. During oxyfluorfen action, the TTS4 line had greater herbicide resistance than the AP1 line, indicating that the dual expression of M. xanthus Protox in chloroplasts and mitochondria prevented the accumulation of photodynamic protoporphyrin IX more effectively than the expression of Arabidopsis Protox only in chloroplasts. These results suggest that the ectopic expression of Protox in mitochondria greatly contributes to the herbicidal resistance in rice plants.

• Weed & Turfgrass Science
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• v.7 no.3
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• pp.201-208
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• 2018

This study was conducted to investigate the occurrence and distribution of herbicide resistant weeds at rice fields in Chungnam province of Korea in 2017. Herbicide-resistant weeds occurred in 64,782 ha, which comprise 47.0% of the total paddy field area of Chungnam province. The infested area of herbicide resistant weeds was estimated in Seosan-si (11.9%), Nonsan-si (11.1%), Dangjin-si (10.9%), Boryeong-si (9.2%) and Asan-si (7.8%). The most dominant herbicide resistant weeds in rice fields were Monochoria vaginalis, followed by Lindernia dubia, Schoenoplectus juncoides, Echinochloa oryzicola, Cyperus difformis and Sagittaria trifolia. Herbicide resistant M. vaginalis, L. dubia, and S. juncoides occurred throughout Chungnam province, and herbicide resistant S. trifolia was only found in Dangjin-si. Compared with the 2011 survey, the infested area of herbicide-resistant weeds decreased, but the incidence rates were similar. The herbicide rotation with different modes of actions across growing seasons is recommended to control herbicide-resistant weeds in the infested fields. It is necessary to monitor herbicide resistance regularly and conduct integrated herbicide resistance management in this area.

• Korean Journal of Weed Science
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• v.16 no.4
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• pp.362-371
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• 1996

In this study, the relationships between sensitivity to oxyfluorfen, absorption of the herbicide, protoporphyrin IX(Proto IX) accumulation and activities of antioxidative enzymes were examined to identify the tolerance mechanism against oxyfluorfen in various rice cultivars having different level of tolerance to this herbicide. Absorption of oxyfluorfen in tolerant rice cultivars was slower than in susceptible cultivars. Proto IX accumulation in various rice cultivars treated with oxyfluorfen was higher in susceptible cultivars than in tolerant ones. In susceptible cultivars especially, Proto IX accumlated rapidly during the herbicide treatment in the dark. Large amounts of Proto IX accumulation were considered to cause membrane lipid peroxidation in the light. However, among the tested rice cultivars, there was little relationship between their tolerance to oxyfluorfen and the activities of antioxidative enzymes. Therefore, it is assumed that differential susceptibility of rice cultivars to oxyfluorfen was due to difference in their capability to absorb the herbicide and to subsequently accumulate Proto IX.

• Korean Journal of Weed Science
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• v.32 no.3
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• pp.170-173
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• 2012

China is one of most important countries for production and consumption of herbicide. Although the chemical weeding technology promoted the development of agricultural modernization in Chinese, it led to the negative effects to agriculture. In particular, the weeds resistant herbicide in paddy field had been serious challenge for safe production of rice. The chemical control technology for weed resistant herbicide with effective, low cost and safety characteristic will be key problem being solved in futhure.

• Korean Journal of Weed Science
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• v.18 no.1
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• pp.20-27
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• 1998

This experiments were conducted to investigate the effects of fertilizer for herbicides phytotoxicity of rice(Oryza sativa L. japonica cv Dongjin). The shoot and root growth of rice were inhibited more by pyrazosulfuron-ethyl or pyrazosulfuronethyl+molinate than bensulfuron methyl or bensulfuron methyl+dimepiperate application in nitrogen or nitrogen mixed solution. In phosphate or phosphate mixed solution, rice growth were inhibited more by bensulfuron methyl or bensulfuron methyl+dimepiperate than pyrazosulfuron-ethyl or pyrazosulfuron-ethyl+molinate application. In solution mixed with nitrogen and phosphate or fertilizer three elements, rice shoots were more. inhibited by pyrazosulfuron-ethyl or pyrazosulfuron-ethyl+molinate treatments, roots were inhibited more relatively by bensulfuron methyl or bensulfuron methyl+dimepiperate treatments. In all fertilizer solutions, rice plant heights were reduced by dimepiperate and molinate applications, but root growth was reduced only by nitrogen and phosphate mixed solution. Rice growth in sulfonylurea or their mixed herbicide application were more inhibited in high :nitrogen concentration arid by phosphate exclusion than by nitrogen exclusion culture.

• Korean Journal of Agricultural Science
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• v.42 no.1
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• pp.15-22
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• 2015

This study was conducted to evaluate the phytotoxicity of imazosulfuron+fentrazamide mixture in rice field. It is recommended that safe herbicide application was obtained at 3 cm of transplanting depth and in sandy loam or loam soil type. In the direct water seeding of rice, imazosulfuron+fentrazamide SC should be applied at least 10 days before sowing land ower than 25+100 g ai/ha. In case of imazosulfuron+fentrazamide SC application after sowing, If we use the herbicide 15 days after sowing, no herbicide symptoms will be detected even though the amounts of the herbicide increase. In the rice transplanting, it is recommended that imazosulfuron+fentrazamide GR is applied 5 days after transplanting. In case of sequential herbicide application, the imazosulfuron+fentrazamide SC application at 75+300 g ai/ha 15 or 20 days after transplanting after the application at 25+100 g ai/ha or 50+200 g ai/ha 3 days before sowing increases weed control efficacy and gives no phytotoxicity in the rice growth.

• Korean Journal of Weed Science
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• v.10 no.4
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• pp.285-293
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• 1990

The response of callus growth of rice (Oryza sativa L.) cultivars which showed different responses to herbicides as seedlings was investigated to select resistant or tolerant calli. Callus growth of IR28 which was susceptible to thiobencarb (S-[(4-chlorophenyl)methyl]diethylcarbamothioate) during callus induction was not inhibited by $10^{-5}$ M and $10^{-6}$ M thiobencarb, indicating that there was a difference in tolerance among callus induction and growth, and the intact plant level. A similar result was obtained with IR31917-45-3-2-2 to butachlor [N - (buthoxymethyl) -2-chloro-N- (2, 6-diethylphenyl) acetamide]. The fresh weight of IR28 callus transferred into $10^{-5}$ M thiobencarb after treatment at $10^{-6}$ M for 30 days was not affected by the herbicide, indicating that transferring callus into gradually higher herbicide concentrations can be a useful method for selection of herbicide-tolerant cell lines.