• Applied Biological Chemistry
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• v.39 no.1
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• pp.70-76
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• 1996

A series of the herbicidal pyridylsulfonyl areas, none substitutent, 1-(4,6-dimethoxypyrimidine-2-yl)-3-(2-pyridylsulfonyl) urea, 3 and 3-trifluoromethyl substitutent, 1-(4,6-dimethoxypyrimidine-2-yl)-3-(3-trifluoromethyl-2-pyridylsulfonyl) urea, 5(Flazasulfuron) were synthesizied and the rate of hydrolysis of their has been studied in 25%(v/v) aqueous dioxane at $45^{\circ}C$. From the results of solvent effect($m{\ll}1,\;n{\ll}3\;&\;{\mid}m{\mid}{\ll}{\mid}{\ell}{\mid}$), thermodynamic parameter (${\Delta}S^{\neq}=0.54{\sim}\;-2.19\;e.u.\;&\;{\Delta}H^{\neq}=0.025\;Kcal.mol.^{-1}$), hydrolysis product analysis, $pK_a$ constant(3: 4.9 & 5: lit.4.6) and the rate equation, a marked difference in the kinetics of the reaction of 3 and 5(Flazasulfuron) was observed. It may be concluded that the hydrolysis of 5 proceeds through the $A-S_N2Ar$ reaction via conjugate acid$(5H^+)$ below pH 7.0, whereas, above pH 9.0, the hydrolysis proceeds through irreversibly $(E_1)_{anion}$ and reversibly $(E_1CB)_R$ mechanism via conjugate base(CB), respectively. But in case of 5, $A-S_N2Ar,\;(E_1)anion\;and\;(E_1CB)_R$ mechanism involved Smile rearrangement. The mate of rearrangement of 5 to a 3-trifluoromethyl-2-pyridylpyrimidinyl urea(PPU) in acid and 3-trifluoromethyl-2-pyridyl-4.6-dimethoxypyridinyl amine (PPA) in base was increased about 3.5 times by the introduction of trifluoromethyl group in the 3-position on the 2-pyridyl ring. From the basis of these findings, a possible mechanism for the hydrolysis of 5 was proposed and discussed.

• Korean Journal of Weed Science
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• v.15 no.4
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• pp.262-269
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• 1995

The reseach was conducted to find out if there are any difference in growth, specific pattern in weed competition, and herbicide response of Korean lawngrass(Zoysia japonica Steud.) in a green house equipped with auto-foggy system. Plant height and leaf stage of Korean lowngrass under foggy condition were increased through all growing stages, whereas the number of tillers and shoot fresh weight harvested at 100 days after seeding were reduced by 24% and 29%, respectively, comparing with non-foggy condition. Weed emergence(total fresh weight) under foggy condition was much greater than that under non-foggy condition. Plant height, number of tillers, number of plant and shoot fresh weight of lawngrass under foggy condition were severely reduced with increasing the duration of competition(above 40 day-competition). Among the herbicides treated, oxyfluorfen completely inhibited plant height of lawngrass regardless of foggy condition, and bensulide considerably inhibited plant height of lawngrass under foggy condition. On the other hand, flazasulfuron did not affect the growth of lawngrass under both foggy and non-foggy conditions. At 40 days after herbicides application, weeding efficacy of bensulide and mecoprop under foggy condition were reduced by 6% and 13%, respectively, comparing with non-foggy condition.

• Weed & Turfgrass Science
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• v.3 no.2
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• pp.110-113
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• 2014

The continuous use of acetolactate synthase (ALS) and acetyl-CoA carboxylase (ACCase) inhibitors has led to the selection of herbicide resistant barnyardgrass populations in direct-seeded rice fields of Korea. This study was conducted to identify herbicide resistant barnyardgrass biotypes and to determine the cross- and multiple-resistance of them. 25% of the population collected from Taeahn was partially resistant to ACCase inhibitors and 22% collected from Kimjae were partially resistant to ALS inhibitors. However, 8.2% of the population from both sites was resistant to ALS and ACCase inhibitors. Resistance to sulfonylurea herbicide, flazasulfuron was identified from two barnyardgrass accessions collected from both Taeahn and Kimjae. One barnyardgrass accession from both sites was resistant to ACCase inhibitor, sethoxydim. The cross-resistance to ALS inhibitors was identified at one barnyardgrass accession from Taeahn and at two accessions from Kimjae. Further, crossresistance to ACCase inhibitors was also identified at barnyardgrass accessions from Taeahn and Kimjae. Multiple-resistance to flazasulfuron and sethoxydim was determined at four barnyardgrass accessions from Taeahn and at six accessions from Kimjae. Therefore, the herbicide mixture and sequences within a growing season or the herbicide rotation with different modes of actions across growing seasons are recommended to control herbicide-resistant barnyardgrass in infested fields.

• Proceedings of the Turfgrass Society of Korea Conference
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• 2002.02a
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• pp.3-5
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• 2002

This study was carried out to get better understandings about morphological, ecological, and genetical characteristics of annual bluegrass collected from different golf courses in Korea and eventually to establish a successful control strategy. Twenty five local lines of annual bluegrass collected from 20 golf courses in Korea were classified into annual or perennial type on the basis of morphological characteristics. Twelve local lines showing obvious morphological differences were selected and then genetically assessed using RAPD analysis. Classification of the 12 local lines through RAPD analysis were considerably similar to that determined by both of morphological differences and phenotype. Responses of the two types of annual blugrass to herbicides were also examined. Shoot growth of annual bluegrass was significantly suppressed by flazasulfuron and the annual type was more susceptible than perennial type, regardless of flazasulfuron concentrations used. By pendimethalin treatment, there was no clear difference in susceptibility between the two types of annual bluegrass. However, by the treatment of dithiopyr, annual type was more sensitive than perennial type in both shoot and root growth. Nine tree species were screened to detect their allelopathic potential on turfgrasses and annual bluegrass. Acacia (Robinia pseudo-acacia) leaves showed selective inhibition in the shoot and root growth as well as their seed germination when treated with 2% and 10%(v/v) of the extract. However, the other leaf extracts except acacia inhibited non-selectively the growth of three turfgrass species such as bentgrass, perennial ryegrass and zoysiagrass and annual bluegrass. The PAL activities of annual bluegrass increased at 24 h after treatment of acacia leaf extract and peaked at 36 h and then decreased till 60h. The highest PAL activity was observed at 36h after treatment of 10%. The highest activity of CA4H in annual bluegrass was observed at 2h after treatment of acacia extract and the level was 4 times greater than that of the control. The phenolic acids such as p-coumaric acid, salicylic acid and ferulic acid were increased with the treatment of acacia leaf extract. The chloroplast membrane and cell wall of annual bluegrass were destroyed by treatment of acacia leaf extract and its inner materials were released. The membranes in annual bluegrass cells might be destroyed by phytotoxic compounds from acacia leaf extract.

• The Korean Journal of Pesticide Science
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• v.4 no.4
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• pp.81-86
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• 2000

The objective was to develop herbicides for liquorice (Glycyrrhiza uralensis), one of most important ingredients of herbal medicine in Korea. Soil-applied herbicides, pendimethalin at 1,585 g a.i. $ha^{-1}$, simazine at 1,000 g a.i. $ha^{-1}$, alachlor at 5 g a.i. $ha^{-1}$, metolachlor at 1,600 g a.i. $ha^{-1}$, and ethalfluralin at 1,050 g a.i. $ha^{-1}$ provided greater control of hairy crabgrass and barnyardgrass (> 60%) but less control of Abutilon avicennae and Fagopyrum esculentum under growth chamber conditions. Of tested soil-applied herbicides, pendimethalin and simazine showed slight injury to liquorice (<17%). In the field experiment conducted in Chunchon, pendimethalin and simazine provided greater control of weeds: total fresh weight of weeds in control plots was 187 g $m^{-2}$, while those in both herbicides-treated plots were nil. Fresh weights of liquorice seedlings in pendimethalin- and simazine-applied plots, however, were not different from those in control plots. Foliar-applied herbicides, such as dicamba at 964 g a.i. $ha^{-1}$, 2,4-D at 280 g a.i. $ha^{-1}$, mecoprop at 2,500 g a.i. $ha^{-1}$, flazasulfuron at 75 g a.i. $ha^{-1}$, imazaquin at 800 g a.i. $ha^{-1}$, bentazon at 1,600 g a.i. $ha^{-1}$, and pyribenzoxim at 30 g a.i. $ha^{-1}$ reduced the growth of liquorice seedlings and provided moderate to total damage. Overall results show that pendimethalin and simazine appears to be effective herbicide candidates for liquorice.

• Asian Journal of Turfgrass Science
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• v.11 no.3
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• pp.149-159
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• 1997

A study was carried out in order to elucidate utilization of agochemicals in golf courses scien-tifically. The analysis of amounts of agrochemical used in golf courses from 1991 to 1996 which were reported to government are ;Despite of increase of golf courses, the amounts of agrochemicals decreased from 1992 as turning point. The decrease of utilization of insecticides and herbicides made it possible. In fungicides, thiopanate-methyl WP, polyoxine D. thiram WP and iprodione WP were used much in general and their utilization ratios were high. In recent year, as fungicides for Pythium blight and large patch, oxapro WP and pencycuron WP's amounts of utilization increased, but utilization ratios were under 70%. In insecticides, penitrothion OL's quantity consumed and utilization ratios were the best, but showed tendency of decrease as registration of agrochemicals for turfgrass expanded. In herbicides, bensulide OL, napropamide WP, MCPP SL were used much and their utilization ratios were high. In recent year, flazasulfuron WP's amounts of utilization and utilization ratio increased relatively. Key words: Agrochemicals Golf courses, Insecticides, Herbicides,Fungicides.

• Weed & Turfgrass Science
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• v.2 no.1
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• pp.76-81
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• 2013

This study was performed to find the effective post-emergence herbicides to control of Poa annua that has already emerged from the soil in Kentucky bluegrass. A total of 8 treatments consist of various post-emergence herbicides applied at recommended concentration or lower concentration than recommended concentration to prevent Kentucky bluegrass injury in this study. Methiozolin showed the least injury in Kentucky bluegrass during 40 days after treatments and there were no footprints by methiozolin in creeping bentgrass green during 20 days. However, Poa annua control was 60.4%, which was less than those of other 7 treatments in this study. Both of asulam sodium and iodosulfuron plus asulam sodium exhibited the higher Poa annua control of 81.7% and 82.2% respectively without serious injury in Kentucky bluegrass during 40 days, and they showed a slight footprints damage in creeping bentgrass green. On the other hand, critical Kentucky bluegrass injuries and the vivid and numerous footprints were occurred in treatments of trifloxysulfuron-sodium, foramsulfuron, rimsulfuron and flazasulfuron, even though they were applied with only 1/4 of recommended concentration. Methiozolin is available to reduce gradually Poa annua population on Kentucky bluegrass without severe turfgrass damage. Asulam sodium or iodosulfuron plus asulam sodium could be useful to remove Poa annua by spot treatment but it is prohibited to spray directly on green even spot.

• Weed & Turfgrass Science
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• v.2 no.2
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• pp.111-121
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• 2013

Literatures were reviewed to understand the weeds occurring on the lawn and the effective control methods of them. Thirty-seven species of 16 families including three species of Cyperaceae for example Cyperus sanguinolentus, nine species of Poaceae including Digitalis ciliaris, Poa repens, etc., and 25 species of broad-leaved weeds such as Artemisia princeps, Draba nemorosa, Hydrocotyle sibthorpioides were occurred on the lawns. One hundred ninety-six weed species of 53 families were occurred on a tomb graveyard adjacent to the mountain. Therefore, it is possible to be infested by the weeds occurring on the graveyard on the golf course adjacent to the mountains. There are 67 items, 32 kinds of the soil treatment herbicides including dichlobenil GR, methiozolin EC, oxaziclomefone SC, imaxaquin GR et al, and 35 kinds of the foliar treatment herbicides including metamifop EC, bifenox flucetosulfuron WG, flazasulfuron WP, trifloxysulfuron-sodium WG et al. registered at the end of May 2012 for efficient management of the weeds occurring on the lawn. For effective management of the weeds, the herbicide can be generally applied twice a year on March to April and August to September for soil treatment and once a year on June to July for the foliage treatment.