• Korean Journal of Weed Science
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• v.12 no.2
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• pp.132-143
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• 1992

The study was conducted to find out synergistic effects by interaction on the basis on anatomical changes between paddy rice and weed species by mixture use of oxyfluorfen and bensulfuron at 0, $10^{-6}$ and $10^{-4}$M, respectively. Tissues were sampled at 72 hrs after soaking treatment and prepared for light microscopic examination and sectioned longitudinally and transversely stem into $8{\mu}m$ thick. As the results of microscopic examination, the major response of treated plant involved rupture and constrict in mesophyll cells and epidermal cells, and shrinks in bundle sheath cells by oxyfluorfen and disorganization and swelling in meristems by bensulfuron. Anatomical changes in rice was the least affected by even high concentration and two herbicide mixtures, whereas Echinochloa crus-galli was severely disorganized in meristem regions and ruptured in epidermal cells by mixture use. Monochoria vaginalis was completely ruptured by any treatment concentrations and mixtures. Scirpus juncoides was considerably tolerant to both herbicides and their mixture and was similar to those that occur in rice. Perennial weed, Sagittaria pigmaea was observed vacuolation, non-nucleation of cell, and irregular cell layering but in mixture injury was slight. Cyperus serotinus was severely shrunk and ruptured by mixture treatment. Eventually anatomical variations in all weed species was shown synergistic effect by use of herbicide mixtures.

• Korean Journal of Weed Science
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• v.30 no.4
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• pp.429-436
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• 2010

Herbicidal activity and characteristics of chrysophanic acid were investigated in semi-field condition. At early and middle post-emergence, Trifolium repens appeared to be very susceptible to chrysophanic acid of $2,000{\mu}g\;mL^{-1}$. However, herbicidal activity of chrysophanic acid of $2,000{\mu}g\;mL^{-1}$ estimated by visual injury to Artemisia princeps was not caused considerable phytotoxicity. Also by foliar application, the concentration of crysophanic acid for effectively control to Polygonum aviculare was much higher than $2,000{\mu}g\;mL^{-1}$. Herbicidal activity of chrysophanic acid to Echinochloa crus-galli, Cypres difformis, Setaria viridis, Digitaria sangguinalis, Bidens tripartita by foliar application was more effective at concentration ranges from 4,000 to $6,000{\mu}g\;mL^{-1}$. These results suggest that chrysophanic acid demanded for higher than $2,000{\mu}g\;mL^{-1}$ to successful weed control in the field condition.

• Korean Journal of Weed Science
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• v.6 no.2
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• pp.134-145
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• 1986

The experiment was crried out to evaluated the herbicidal properties of bensulfuron methyl [methyl 2-[[[[[(4, 6-dimethoxy pyrimidine-2yl) amino] carbonyl] amino] sulfonyl] methyl] benzoate]. No phytotoxicity was observed when bensulfuron methyl was applied at 3 and 6 g a.i./ 10a while the application rate 12 g a.i./10a slightly retared the growth of rice. The phytotoxicity decreased as the application time was delayed. The effect of application rate, leaching grade, transplanting depth, soil type and temperature on crop injury was little. Japonica variety (Dong-Jin) was more sensitive to bensulfuron methyl than indica X japonica variety (Sam-Kang). Bensulfuron methyl controlled effectively perennial weeds such as Sagittaria pygmaea Miq., Potamogeton diatinctus A. Benn., Cyperus serotinus Rottb., Sagittaria trifolia L., Eleocharis kuroguwai Ohwi. including most annual weeds except Echinochloa crus galli P. Beauv. The effect slightly decreased with lowering the temperature increasing the leaching grade. Application time and soil type employed did not affect the weeding effect.

• Korean Journal of Weed Science
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• v.30 no.2
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• pp.143-152
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• 2010

Herbicidal characterisitcs of natural product chrysophanic acid were investigated in a greenhouse condition. At early- and middle-stage post-emergence treatments, several grasses and broadleaf weeds appeared to be very susceptible to chrysophanic acid. However, any significant herbicidal activity treated by pre-emergence did not occur at concentration ranges from 31.3 to 1,000 ug $mL^{-1}$. Herbicidal activity of chrysophanic acid estimated by visual injury for large crabgrass was much higher when applied at 7 to 14 days after seeding than at 21 and 28 days after seeding. By post-emergence treatment, chrysophanic acid caused very considerable phytotoxicity on several grasses and broadleaf crops. In herbicidal interaction experiments determined by Colby's method, the effect of chrysophanic acid and caryophyllene oxide tank-mixture showed very high synergistic activity. Although chrysophanic acid did not give any pre-emergence effect, herbicidal spectrum tended to be very wide and strong when treated by post-emergence. These results suggest that chrysophanic acid possesses a possible potential to develop as a natural herbicide.

• Asian Journal of Turfgrass Science
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• v.19 no.2
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• pp.65-72
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• 2005

Creeping bentgrass (Agrostis palustris Huds.) had been the problematic weed for Kentucky bluegrass (Poa pratensis L.) fairway since it shows light green color all year. Experiment was carried out to determine the best herbicides combination to control creeping bentgrass in Kentucky bluegrass. fairway without injury. To investigate the efficacy of herbicides, five post-emergence herbicides of asulam WG ($87.6\%$), imazaquin SL ($20\%$), fenoxaprop-P-ethyl EC ($7\%$), mecoprop SL ($50\%$), triclopyr-TEA SL ($30\%$) and one pre-emergence herbicide pendimethalin EC ($31.7\%$) treated on 21 Sept. and 10 Nov. 2003. Kentucky bluegrass visual quality evaluated 30 and 50 days after application for phytotoxic effects of the herbicides. As a result, asulam WG (0.2g/$m^{2}$) and imazaquin SL (0.3ml/$m^{2}$) showed approximately $90\%$ of control in creeping bentgrass, but visual quality of Kentucky bluegrass significantly decreased from 20 to 50DAT (day after treatment). However, creeping bentgrass was acceptably controlled(over $80\%$) by fenoxaprop-P-ethyl EC (0.4ml/$m^{2}$)+triclopyr-TEA SL(0.3 ml/$m^{2}$) applied twice on 21 Sept. and 1 Oct. 2003 without serious injury on Kentucky bluegrass. Therefore, it is suggested that an application of fenoxaprop-P-ethyl EC (0.4ml/ $m^{2}$)+triclopyr-TEA SL (0.3 ml/$m^{2}$) may be more effective to control creeping bentgrass in Kentucky bluegrass with the least phytotoxicity by herbicides.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.2
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• pp.160-165
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• 2012

A field study was conducted at Miryang in 2011 to evaluate differential sensitivity of six rice cultivars, three Indica${\times}$Japonica rice (long grain, cv. Hanareumbyeo, Hanareum2, Dasanbyeo) and three Japonica rice (short grain, Nampyung, Ilpumbyeo and Junamjosaeng) cultivars, to benzobicyclon, mesotrione+pretilachlor (MP) and butachlor (control) in transplanting rice and their treatment influences on rice yield. All Indica${\times}$Japonica rice cultivars exhibited susceptible to both benzobicyclon and MP as reflected by higher visual injury and carotenoid biosynthesis inhibition when compared with Japonica rice cutlivars. The percentage of foliar chlorosis of Indica${\times}$Japonica rice was only 0.9~4.7% for benzobicyclon at 13 days after treatment (DAT) and 30.3~64.4% for MP at 5DAT but it increased rapidly to 88.4~91.2% at 12~20DAT. However, most of the Japonica cultivars are tolerant to bezobicyclon and MP. There was no visible leaf chlorosis but carotenoid biosynthesis was slightly inhibited. Based on relative carotenoid content reduction of benzobicyclon and MP to butachlor, the Indica${\times}$Japonica rice showed 4.6~15.6 fold higher compared with the Japonica rice. The heading date of the injured rice plant was delayed by 3 days and panicle number per square meter and ripened grain ratio were reduced as compared with the control treatment of butachlor. Rice yield of the Indica${\times}$Japonica rice cultivars treated with benzobicyclon and MP was reduced by 7~10%, 3~5%. respectively. The result indicates that rice cultivars vary in tolerance to HPPD-Inhibiting herbicides and Indica${\times}$Japonica rices were more susceptible than the Japonica rices to MP and benzobicyclon. Rice yield of the Indica${\times}$Japonica rices was also significantly reduced by the those herbicide treatments.

• Korean Journal of Weed Science
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• v.30 no.3
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• pp.272-281
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• 2010

The objective of this research was to find out the weed management techniques in environment-friendly rice paddy fields through the study on herbicidal effects and problems of various organic materials. This experiment was conducted under different conditions of weed species and weed densities in environment-friendly rice paddy fields. There was no difference in weedy efficacy on golden apple snail (GAS), paper mulching (PM), and machine weeding (MW) between low and high weed densities. However, the effect of weed control in rice bran (RB) and effective microorganism (EM) + molasses was higher in high weed density than in low weed density. In general, the effect of weed control as affected by various organic materials was in the order of GAS (97-100%) > PM (93-98%) > RB (15-80%) > EM (7-31%). GAS provided excellent control of all weed species tested except for Persicaria hydropiper. PM gave acceptable control of the weed species except for Echinochloa crus-galli, Ludwigia prostrata, and Eleocharis kuroguwai. However, MW gave fair control (70% biomass reduction) of all weed species tested. BR followed by MW or EM followed by MW treatments had similar effect on weed control compared to each treatment alone. However, BR followed by GAS or EM followed by GAS provided 100% control of weed species tested. The level of rice foliar injury caused by various organic materials was in the order of GAS and MW (10-20%) > RB (10-15%) > PM and EM (5-7%). Typical symptoms of organic materials are wilting, inhibition of growth, missing hill, and reduction of tiller. Cost for weed control of GAS, RB, EM, and PM were 2.1, 3.1, 2.3, and 13.2 times higher than that of the herbicide. These data indicate that GAS was the best method for weed management in environmentfriendly rice paddy fields. Further study is required to elucidate the mechanisms underlying the rice injury as affected by GAS.

• Korean Journal of Organic Agriculture
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• v.29 no.2
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• pp.223-240
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• 2021

This study was carried out to investigate the economic value of organic wheat production using gelatin·chitin microorganisms in Gwangsan-gu, Gwangju city. The soil condition of experiment field was clay loam Jisan series. The organically cultivated fields were sprayed gelatin and chitin degrading bacteria. The test was performed at conventionally cultivated field and organically cultivated field. Emergence of weed on organically cultivated field was significantly higher than conventionally cultivated field which sprayed herbicide before seeding. Weed emergence have a critical impact on grain yield. Occurrence of diseases and insect pests were higher than conventionally cultivated fields. In 2019, the amount of lodging in conventionally cultivated field were higher than conventionally cultivated field. In 2020, lodging and wet injury were occur in both field. Comparing yield element between organically and conventionally cultivated experimental area, grain yield in organically cultivated field was shown slightly higher amount than conventionally cultivated field. However in the actual yield of 2019, organically cultivated field shows 20% deceased yield because of overgrown weed. In 2020, weed emergence and yellow mosaic virus by wet injury cause 30% decease in the grain yield in organically cultivated field. Content of protein, carbohydrates, ash, water and fat in the grain were not different significance. In 2019, net incomes of conventionally cultivated wheat was 461,031 won/0.1 ha while organically cultivated wheat was 443,437 won/0.1 ha. In the rate of income, conventionally cultivated field was 83.0% as against organically cultivated field (73.3%). In 2020, net incomes of organically cultivated wheat was 437,812 won/0.1 ha while conventionally cultivated wheat was 418,281 won/0.1 ha. In the rate of income, conventionally cultivated field was 81.6% as against organically cultivated field (73.0%).

• Korean Journal of Weed Science
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• v.17 no.4
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• pp.362-367
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• 1997

A field experiment was conducted to determine an optimum control time of water foxtail(Alopecurus aequalis var. amurensis Ohwi), a most troublesome weed, in no-tillage dry seeded rice. Paraquat, a non-selective herbicide, was applied at 1.5 days interval from March 15 to May 15 at a concentration of 3,000ml per hectar and its control efficacy to A. aequalis was recorded before and after seed sowing. In addition. other characters such as decayed injury of A. aequalis to rice seedling, and its influence of seedling stand were also investigated in relation to rice grain yield. Dry weight of A. aequalis was rapidly increased with delay in control time from 42g/$m^2$at March 15 to 237g/$m^2$ at May 15. The amount of its regrowth at seeding time was highest with 68.3g, when paraquat was applied at March 15, then decreased thereafter and it was less than 6.2g when paraquat was applied after April 15 which indicates above 98% control rate. The control rate of A. aequalis, at 30 days after paraquat application way likewise similar to that the seeding time. Rice seedling stands in the plot treated with paraquat before April 15 were not affected by decayed injury of A. aequalis while decayed injury of 3 to 4 degree for those after April 30 application was noted. Dwarf virus disease on rice seedling due to occurrence of A. aequalis was not observed when A. aequalis was controled from March 30 to May 15 while it was occurred in the plot of March 15 application and the untreated control. The control plot of A. aequalis at April 15 had the highest grain yield with 4.79ton/10a. Based on control rate of A. aequalis, seedling stands of rice, virus disease, and rice grain yield, the most suitable control time of A. aequalis in no-tillage dry seeded rice is considered to be about April 15.

• Korean Journal of Weed Science
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• v.7 no.3
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• pp.306-315
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• 1987

In the red pepper field under polythylene film mulching(P.E.-mulching) culture, the weed emergence was completely inhibited by black P.E.-mulching. The emergence in clear P.E.-mulching decreased 90% compared to that in non-mulching. Weeding effect was high in the order of pendimethalin, diphenamid, alachlor and napropamide. The effect of herbicides was higher in clear P.E.-mulching than in non-mulching. Plant height and number of branches increased in the order of clear P.E.-, black P.E.-mulching, while the yield between black P.E.- and clear P.E.-mulching was not different. The herbicides had no effect on the growth and yield. In the peanut field, weed emergence was 80% lower in clear P.E.-mulching than in non-mulching. Weeding effect was excellent in the plot applied with alachlor, napropamide and diphenamid. The total number of branches, main stem height and shoot weight were 2.0, 1.7 and 2.4 times greater in clear P.E.-mulching than in non-mulching, respectively. Peanut yield was about 38% higher under clear P.E.-mulching than under non-mulching. The herbicides had no effect on the growth and yield. In the sesame field, rate of weed emergence was 10 times lower in clear P.E.-mulching than in non-mulching. Weeding effect of alachlor, napropamide and diphenamid was higher under clear P.E.-mulching than under non-mulching. Germination percentage of sesame greatly decreased in non-mulching compared with in clear P.E.-mulching. The germination was inhibited by the treatment of herbicides. The inhibition effect was increased in the order of alachlor, napropamide, and diphenamid. The initial crop injury in treatment of herbicides was greater in non-mulching than in clear P.E.-mulching. The crop recovered from the injury and exhibited regrowth in clear P.E.-mulching except the alachlor treatment, but there was no recovery in non-mulching. There was no significant difference yield between herbicide treatment and hand weeding in non-mulching. Also, no significant difference was obseorbed between napropamide and diphenamid treatment and hand weeding in clear P.E.-mulching.