• Korean Journal of Weed Science
• /
• v.18 no.4
• /
• pp.286-294
• /
• 1998

This study was carried out to evaluate the interaction effect between molinate(S-ethyl N,N-hexamethylene-thiocarbamate) and simetryn(N,N'-diethyl-6-(methythio)-1,3,5-triazine-2,4-diamine) on weed bioefficacy and rice phytotoxicity in green house and paddy field. Combined application of molinate and simetryn showed synergistic herbicidal effect to Echinochloa crus-galli and additive herbicidal effect to Bidens tripartita, However, it showed synergistic phytotoxicity to rice. Combined application of molinate and simetryn reduced the flooding period desirable for controlling Echinochloa crus-galli by about 2~4days as compared to single application of molinate. It was concluded that the optimum combination of molinate and simetryn was 150g and 9g to 18g a.i./10a, respectively in viewpoint of bioefficacy and phytotoxicity.

• Journal of Food Hygiene and Safety
• /
• v.20 no.3
• /
• pp.159-164
• /
• 2005

This method was described for the simultaneous determination of simetryn and buprofezin in rice, vegetables, and fruits by gas chromatography(GC) with nitrogen phosphorus detector. The GC method of simetryn and buprofezin was shown to give a linear detection ranges between $0.019\sim9.306mg/kg,\;0.023\sim11.27mg/kg$, respectively. For evaluation of GC method, simetryn spiked into rice, vegetables and fruits at the level of 4.653mg/kg was determined. The recoveries of simetryn by GC method were ranged from 57.9 to $115.9\%$. For evaluation of GC method, buprofezin spiked into rice, vegetables and fruits at the level of 2.817mg/kg was determined. The recoveries of buprofezin by GC method were ranged from 56.5 to $121.5\%.$

• Korean Journal of Weed Science
• /
• v.18 no.4
• /
• pp.341-347
• /
• 1998

This study was carried out to investigate the effect of U-Granule formulation of molinate(S-ethylhexaphdro-1H-azepine-1-carbothioate) mixtures in green house and paddy field, Five minutes were taken for U-Granule to spread out 7m in irrigated water of direct seeded on flooded paddy surface. The concentration of active ingredient of molinate in molinate U-Granule application was similar to molinate+simetryn U-Granule application. But weeding effect of molinate+simetryn U-Granule on Echinochlor crus-galli was 23% higher Than single application of molinate at 7m from application point. Bioefficacy of molinate+simetryn+imazosulfuron U-Granule on control of Echinochloa crus-galli was higher than that of molinzte+imazosulfuton U-Granule, but those effect on Eleochairs kuroguwai was not significantly different. Only slight rice phytotoxicity was observed at 5m and 2m from application point of U-Granule molinate+simetryn+imazosulfuron and molinate+imazosulfuron, respectively. So it is concluded that there is little phytotoxicity problem in practical application of U-Granule of molinate mixtures.

• Korean Journal of Weed Science
• /
• v.7 no.3
• /
• pp.316-320
• /
• 1987

In order to determine effects of molinate mixture granular formulations on release rate and weed control efficacy of herbicides and growth of rice plants, zeolite impregnation, slurry, and sand-coating granules were tested in laboratory and greenhouse. Release rate of molinate and simetryn was faster in sand-coating granule than in zeolite impregnation and slurry type granules. Mixture granular formulations of molinate/simetryn or molinate/simetryn/MCPB showed good weed control efficacy and this trend was more remarkably shown in sand-coating granule. Sand-coating granule more inhibited growth of rice plants compared to zeolite impregnation and slurry type granules.

• Korean Journal of Weed Science
• /
• v.16 no.2
• /
• pp.140-149
• /
• 1996

Three hundred rice(Oryza sativa L.) cultivars were screened for tolerance to butachlor [N-(buthoxymethyl)-2-chloro-N-(2,6-diethylphenyl) acetamide], thiobencarb(S-[(4-chlorophenyl)methyl]diethylcarbamothioate), and simetryn [N,N-diethyl-6-(methylthio)-1,3,5-triazine-2,4-diamine]. The responses of the rice cultivars to herbicides differed depending upon the herbicides and their concentrations. New Sabarmati(BAS), Gora, PTB 18 were tolerant to butachlor, and Azucena, IR44707-31-1-3-2, ARC 7293 to thiobencarb, while Gora, ARC 7293, and Dudmona were tolerant to both herbicides. Response of rice to simetryn differed from its response to butachlor and thiobencarb. Inhibition of shoot growth and fresh weight increased as the temperature and herbicide concentration increased. There was a higher correlation among rice cultivars response to butachlor and thiobencarb in the greenhouse when laboratory studies were conducted at higher temperatures.

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

• Journal of Environmental Analysis, Health and Toxicology
• /
• v.21 no.4
• /
• pp.304-315
• /
• 2018

Located in Gimhae, Hwapo is the biggest riverine wetland in the province of Gyeongsangsam-do, Korea, and is a major habitat for various species. However, it is suspected that various pollutants enter the wetlands from agricultural and industrial areas. This study identifies major organic pollutants in this wetland and their sources using high performance liquid chromatography-high resolution mass spectrometry during one summer season. Forty-five substances were selected for quantitative analysis using target screening, and other non-selected compounds were screened using suspect and non-target screening methods. The results were that 21 and 17 targeted substances were detected in July and August, respectively. Major pollutants in July and August were oxadiazon (July: 17-220 ng/L, August: 66-460 ng/L), carbendazim (July: 10-110 ng/L, August: 64-520 ng/L), caffeine (July: 33-1,100 ng/L, August: 56-580 ng/L), and niflumic acid (July: 23-75 ng/L, August: 42-290 ng/L). Sampling sites S4 in July and S2 in August were the major inflow points. Ten substances (tricyclazole, hexaconazole, diuron, fexofenadine, irbesartan, simetryn, cimetidine, valsartan, tebuconazole, and benzotriazole) and four metabolites (valsartan acid, azoxystrobin acid, TEB_M324c, and 2-aminobenzimidazole) were tentatively identified through suspect and non-target screening, respectively.