• Weed & Turfgrass Science
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• v.1 no.4
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• pp.64-68
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• 2012

Creeping bentgrass (Agrostis stolonifera L.) is one of the highest maintained turfgrass but often problematic especially for Kentucky bluegrass fairway. Mesotrione is one of selective herbicide that is firstly registered for corn (Zea mays L.) and provides preemergence and postemergence control of broadleaf and annual grassy weeds. Although mesotrione is effective to eradicate area contaminated by creeping bentgrass, protracted time is required to recover damaged area by rhizome extension of Kentucky bluegrass. Overseeding is typically used to fill bare or damaged areas using appropriate turf species to create a uniform turfgrass surface. The objectives of this study were to evaluate mesotrione and seeding rate effects to recover Kentucky bluegrass contaminated by creeping bentgrass. Six treatments consisted of three mesotrione rates and two Kentucky bluegrass seeding rates. The mesotrione rate were 0, 0.05 and 0.10 m $ml^{-2}$. Two seeding rate of to Kentucky bluegrass 'Midnight' were 15 and 30 g $m^{-2}$. Mesotrione application and Kentucky bluegrass overseeding at the same time is helpful to damage creeping bentgrass but not for establishment of Kentucky bluegrass to refill damaged area. To maximize mesotrione effects, temperature above $20^{\circ}C$ would be recommended based on this study.

• Korean Journal of Breeding Science
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• v.50 no.4
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• pp.387-395
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• 2018

This study was conducted to identify DNA markers related to resistance to herbicide containing mesotrione in Tongil type rice. Two Tongil type elite lines; Milyang154 and Suweon382, showed resistance to mesotrione, whereas the others were susceptible at 20 days after mesotrione application, and severe growth inhibition was observed in the remaining 13 lines. As a result of analysis of mesotrione resistance using 190 $F_2$ populations derived from a cross of Hanareum2 (susceptible) and Milyang154 (resistant), the mesotrione resistance locus was shown to be a single dominant gene with a 3:1 segregation ratio ($X^2=1.19$, P=0.31). To identify a DNA marker closely linked to the mesotrione resistance gene, bulked segregant analysis (BSA) was adopted. The DNA marker RM3501 was identified on chromosome 2 with a recombinant value of 0.53 to the mesotrione resistance gene. Mst1(t) was located between SSR (simple sequence repeat) markers RM3501 and RM324 with a physical map distance of 10.2 Mb-11.4 Mb on chromosome 2. The band pattern of agarose gel electrophoresis of the SSR marker RM3501 showed the same segregation pattern with respect to mesotrione treatment in 20 Tongil type varieties and a $BC_2F_2$ segregation population derived from a cross between Unkwang (resistant) and Hanareum2 (susceptible). Thus, the RM3501 DNA marker could be used in breeding programs for Marker Assisted Selection in mesotrione resistant rice breeding.

• Korean Journal of Weed Science
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• v.32 no.3
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• pp.222-229
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• 2012

In this study, we attempted to control invaded hetero-species turfgrass in golf courses with herbicides. Asulam sodium SP and trifloxysulfuron-sodium WG (to control creeping bentgrass in zoysiagrass), trifloxysulfuron-sodium WG (to control kentucky bluegrass in zoysiagrass), and mesotrione SC (to control creeping bentgrass in kentucky bluegrass) were selected as efficient herbicides. To creeping bentgrass, asulam sodium SP and trifloxysulfuron-sodium WG until 70 days after application (DAA), mesotrione SC until 230 DAA and to kentucky bluegrass trifloxysulfuron-sodium WG until 110 DAA; the applications showed 90% herbicidal effect. At 4 X recommended application dose, asulam sodium SP, trifloxysulfuronsodium WG (to zoysiagrass) and mesotrione (to kentucky bluegrass) showed insignificant harmful effect. With recommended dose, asulam sodium SP showed 80% control effect of creeping bentgrass in zoysiagrass until 40 DAA and trifloxysulfuron-sodium WG demonstrated 85% control efficiency until 30 DAA. Trifloxysulfuron-sodium WG controlled 85% of kentucky bluegrass in zoysiagrass until 40 DAA. Mesotrione SC with recommended dose showed 95% control efficiency to creeping bentgrass in kentucky bluegrass.

• Korean Journal of Weed Science
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• v.30 no.3
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• pp.300-307
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• 2010

Greenhouse experiment was conducted to evaluate tolerance of six rice cultivars, three Indica${\times}$Japonica rice (long grain, cv. Dasanbyeo, Segejinmi and Hanareumbyeo) and three Japonica rice (short grain, Nampyung, Ilpumbyeo and Junamjosaeng) cultivars, to mesotrione+pretilachlor (MP) and bensulfuron-methyl+mesotrione+pretilachlor+pyriftalid (BMPP) in transplanting rice. Two herbicides were applied at 90 g and 180 g a.i. $ha^{-1}$ to three to four leaf stage rice at 5 and 15 days after transplanting, respectively. Related study was also conducted to compare $GR_{50}$ for Indica${\times}$Japonica and Japonica rice cultivars at different MP rates. Response to two herbicides varied with respect to rice cultivars and herbicide rates. All Indica${\times}$Japonica rice cultivars exhibited susceptible to both MP and BMPP as reflected by increased visual injury, shorter plant height and higher plant dry matter reduction when compared with nontreated rice cutlivars. The degree of foliar chlorosis by MP at 90 g a.i. $ha^{-1}$ was 5~6 at 7 days after treatment(DAT) but it was decreased to 3~6 at 14DAT. The degree of leaf chlorosis treated with 180 g a.i. $ha^{-1}$ MP was 6~7 at 7DAT and it was also decreased to 3~8 at 14 DAT. The plant hight of Indica${\times}$Japonica rices was inhibited by 18~43% at application of 90 g a.i. $ha^{-1}$ MP and 30~50% at 180 g a.i. $ha^{-1}$ MP. The dry matter reduction was greater than that of plant height inhibition, showing 46~73% at 90 g a.i. $ha^{-1}$ MP and 65~82% at 180 g a.i. $ha^{-1}$ MP. Similar leaf chlorosis injury and growth inhibition of rice cultivars was observed in the BMPP treatment. The injury and growth inhibition by MP and BMPP increased with increase in herbicide rate from 90 g a.i. $ha^{-1}$ to 180 g a.i. $ha^{-1}$. However, most of the Japonica cultivars are tolerant to MP and BMPP at both rates. There was no visible leaf chlorosis but plant height and dry matter production were slightly reduced at 180 g a.i. $ha^{-1}$. Based on $GR_{50}$ value determined in reduction of shoot dry weight for MP, the Indica${\times}$Japonica rice showed 12.9 fold lower compared with the Japonica rice. The result indicates that rice cultivars vary in tolerance to herbicides of MP and BMPP and Indica${\times}$Japonica rices were more susceptible than the Japonica rices to the MP and BMPP.

• Journal of Microbiology and Biotechnology
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• v.24 no.11
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• pp.1473-1483
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• 2014

Reports of herbicide resistance events are proliferating worldwide, leading to new cultivation strategies using combinations of pre-emergence and post-emergence herbicides. We analyzed the impact during a one-year cultivation cycle of several herbicide combinations on the rhizobacterial community of glyphosate-tolerant Bt-maize and compared them to those of the untreated or glyphosate-treated soils. Samples were analyzed using pyrosequencing of the V6 hypervariable region of the 16S rRNA gene. The sequences obtained were subjected to taxonomic, taxonomy-independent, and phylogeny-based diversity studies, followed by a statistical analysis using principal components analysis and hierarchical clustering with jackknife statistical validation. The resilience of the microbial communities was analyzed by comparing their relative composition at the end of the cultivation cycle. The bacterial communites from soil subjected to a combined treatment with mesotrione plus s-metolachlor followed by glyphosate were not statistically different from those treated with glyphosate or the untreated ones. The use of acetochlor plus terbuthylazine followed by glyphosate, and the use of aclonifen plus isoxaflutole followed by mesotrione clearly affected the resilience of their corresponding bacterial communities. The treatment with pethoxamid followed by glyphosate resulted in an intermediate effect. The use of glyphosate alone seems to be the less aggressive one for bacterial communities. Should a combined treatment be needed, the combination of mesotrione and s-metolachlor shows the next best final resilience. Our results show the relevance of comparative rhizobacterial community studies when novel combined herbicide treatments are deemed necessary to control weed growth.

• Weed & Turfgrass Science
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• v.2 no.3
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• pp.248-253
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• 2013

This study was conducted to select alternative herbicides to control herbicide-resistant and - troublesome weeds in rice fields, Korea. The resistant Echinochloa oryzicola to ACCase inhibitor was tested by herbicides registered to control Echinochloa oryzicola. And the resistant and troublesome weeds to sulfonylurea (SU) herbicides, ALS inhibitors, were tested by widely using herbicides to control the resistant weeds in Korea. The oxadiazon, pyrazolate, pretilachlor and benzobicyclone+thiobencarb effectively controlled resistant Echinochloa oryzicola to ACCase and ALS inhibitors at 0.5 leaf stage of the, Herbicides containing mefenacet or fentrazamide controlled effectively by the 2 leaf stage. In controlling other SU resistant weeds including Sagittaria trifolia and Ludwigia prostrate, benzobicyclon and mesotrione performed well all tested weeds, and carfentrazone and pytazolate were effective to broadleaf weeds. Sagittaria trifolia and Ludwigia prostrate, which were suspected to be resistance to SU herbicides, were well controlled by carfentrazone and pytazolate.

• Korean Journal of Weed Science
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• v.32 no.1
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• pp.57-69
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• 2012

This study was conducted to find the effective management of main weeds including herbicide-resistant Echinochloa oryzicola, Scirpus juncoides and Monochoria vaginalis in direct seeded rice on puddled paddy surface. The dominant dominances in direct seeded rice on puddled paddy surface were increased for three years between 2009-2011. In weed distribution in 2011, the occurrence density of S. juncoides decreased greatly, but it of E. oryzicola increased especially as compared with it of 2009. Benzobicyclon, mesotrione and pyrimisulfan were effective to sulfonylurea(SU)-resistant S. juncoides and M. vaginalis at 5 and 12 days after seeding, however, the efficacy of bromobutide to sulfonylurea-resistant M. vaginalis was decreased slightly at 12 days after seeding. And carfentrazon and pyrazolate were ineffective to S. juncoides. In direct seeded rice on puddled paddy surface which ACCase and ALS inhibitor-resistant E. oryzicola was not occurred, benzobicyclon+penoxsulam+pyrazosulfuron-ethyl ET, bromobutide+imazosulfuron+metamifop GR, and flucetosulfuron+mesotrione+pretilachlor GR showed the control effect over 94% to main weeds included sulfonylurea-resistant S. juncoides and M. vaginalis. The E. oryzicola dominating in direct seeded rice on puddled paddy surface were not any affected to the survival by treatment with recommended doses of cyhalofop-butyl and penoxsulam tested. The ACCase and ALS inhibitor-resistant E. oryzicola was effectively controlled by mefenacet and fentrazamide up to the 2nd leaf stage. In direct seeded rice on puddled paddy surface domiating coincidentally by herbicide-resistant E. oryzicola, S. juncoides and M. vaginalis, "one-shot herbicide" included with mefenacet, fentrazamide, penoxsulam and metamifop could't be used because of low control effect or rice injury. The sequential treatment of benzobicyclon+thiobencarb SE and bensulfuron+mefenacet+thiobencarb GR controlled effectively the herbicide-resistant E. oryzicola, S. juncoides and M. vaginalis in direct seeded rice on puddled paddy surface. The days required by the 3rd leaf stage of herbicide-resistant E. oryzicola, S. juncoides and M. vaginalis in direct seeded rice on puddled paddy surface seeded in May 20 shortened by 4 days as compared with it of June 10.

• Korean Journal of Weed Science
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• v.32 no.3
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• pp.240-255
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• 2012

The objectives of this study were to investigate the levels of phytotoxicity of rice varieties to HPPD (4-hydroxy phenylpyruvate dioxygenase)-inhibiting herbicides known for their efficiency to control the sulfonylureas-resistant weed species：mestrione, benzobicyclone, and tefuryltrione. The twenty-six rice varieties (8-Japonica ${\times}$ Indica-type varieties and 18-Japonica-type varieties) were grown for 25 days on seedling trays and then transplanted to paddy rice fields followed by herbicide treatment i.e. standard and double doses of there respective herbicides at 5, 10, and 15 days after transplanting. Although mestrione, benzobicyclone and tefuryltrione are all HPPD-inhibiting herbicides, the phytotoxicity symptoms of the different rice varieties based on the timing of application and doses of the herbicides were significantly different. The Japonica ${\times}$ Indica-type varieties showed much more phytotoxicity symptoms than Japonica-type varieties in all applied herbicides. Increasing herbicidal doses of mesotrione, and an earlier application of and increasing herbicidal doses of benzobicyclon caused severe phytotoxicity symptoms. On the other hand, phytotoxicity due to tefuryltrione did not exhibit significant differences between rice varieties in either the timing of application or dose of the herbicide. Regardless of timing of application and dose of the herbicides, Hangangchalbyeo-1, Hyangmibyeo-1 and high-yield rice varieties such as Namcheonbyeo, Dasanbyeo, Areumbyeo, and Hanareumbyeo, which belong to the Japonica ${\times}$ Indica-type varieties, showed 5 to 8 levels of phytotoxicity symptoms including albinism, browning, detached leaf, and necrosis to mesotrione and benzobicyclon whereas only 1 to 3 levels of phytotoxicity symptoms (chlorosis, albinism, and browning) were seen with to tefuryltrione application. The Japonica-type varieties exhibited only slight phytotoxicity symptoms (1~2 levels) in conformity with the timing of application and doses of the herbicides. However, there were significant differences among the Japonica-type rice varieties, depending on the type of herbicide. Thirteen-Japonica type rice varieties were sensitive to benzobicyclone while 4-Japonica-type and 7-Japonica-type varieties showed phytotoxicity symptoms such as chlorosis and albinism with mestrione and tefuryltrione application, respectively. Therefore, we suggest that the combined-type herbicides including mestrione, benzobicyclone and tefuryltrione should be rejected in paddy fields where rice is grown for either human consumption (functional or processed rice) or livestock feed because of severe phytotoxicity symptoms on the various rice varieties seen regardless of the timing of application and doses of the 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.

• Weed & Turfgrass Science
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• v.4 no.3
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• pp.151-158
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• 2015

This study was conducted to establish the effective weed management methods in rice field simultaneously dominated by the herbicide resistant Echinochloa oryzicola, Monochoria vaginalis and Scirpus juncoides. Herbicides registered for use before transplanting, oxadiazon 12% EC, pyrazolate 36% SC, pretilachlor 14% EC and thiobencarb 50% EC were effective until 0.5 leaf stage of herbicide resistant Echinochloa oryzoides. Herbicides registered for use after transplanting, fentrazamide 1% GR and mefenacet 18% SC were effective until 2 leaf stage of herbicide resistant Echinochloa oryzicola and triafamone 0.98% SC was possible to control up to 4 leaf stage. HPPD inhibitors, benzobicyclon, mesotrione and tefuryltrione SC, were simultaneously effective to SU herbicide-resistant Monochoria vaginalis and Scirpus juncoides. Herbicides registered for use before transplanting, benzobicyclon + oxadiargyl EC out of the tested herbicide was most effective in rice field simultaneously dominated by the herbicide resistant Echinochloa oryzicola, Monochoria vaginalis and Scirpus juncoides. Its effectiveness rises in proportion to flooding duration. Mazosulfuron GR, a herbicides registered for use after transplanting was most effective without phytotoxicity until 60 days after transplanting in rice field simultaneously dominated by the herbicide resistant Echinochloa oryzicola.