• Korean Journal of Weed Science
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• v.16 no.1
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• pp.28-35
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• 1996

Tetrapion(2,2,3,3-tetrafluoropropionate sodium) has commonly been used for reed(Phragmites communis Trin.) control in uncultivated areas, especially in Japan. As an attempt to establish the screening system for selective herbicide controlling reed, tetrapion was tested as a standard herbicide to various weeds and crops including rice in a greenhouse. Symptoms of yellowing, twisting, stunting, and necrosis were observed in the herbicide-treated plants. The herbicide caused a severe damage on all crops examined, except cotton. Both direct seeded and transplanted rice were also sensitive to the herbicide. Its herbicidal activity was generally higher on grass weeds than on broadleaf weeds. It had a higher herbicidal activity with preemergence treatment than with postemergence treatment. In addition, field and greenhouse experiments were conducted to examine the effect of the herbicide on reed control. Its effect varied with the soil type of the treated field and the growth stage of reed. A relatively high dosage of the herbicide was required to control reed. It had an almost same effect on fairygrass(Miscanthus sinensis Anderss) as on reed. However, reed grown in a greenhouse was effectively controlled by the herbicide, having more effect with preemergence treatment than with postemergence treatment as observed in other plants treated with the herbicide. In conclusion, tetrapion has a great potential as a standard herbicide during the herbicide screening for selective reed control.

• Journal of Microbiology and Biotechnology
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• v.16 no.1
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• pp.52-56
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• 2006

The effect of bensulfuron-methyl on the nontargeted cyanobacteria was greater on A. variabillis than N. commune. Both A. variabillis and N. commune were initially able to utilize low concentrations of the herbicide, bensulfuron-methyl, whereas higher concentrations of bensulfuron-methyl or the hydrolyzed products of the herbicide were found to be toxic. Growth and photosynthesis inhibitions of over $50\%$ were observed, when 8 to 10 ppm of the herbicide was applied. Nitrogenase activities of the cyanobacteria were decreased by $94-98\%$ in A. variabillis and by $85-86\%$ in N. commune after 24 h of incubation with 10 ppm and 20 ppm of bensulfuron-methyl. Nitrogenase activities were also inhibited by the addition of ammonium salts as low as 0.05 mM. Furthermore, the toxic effect of the herbicide was the highest at pH 4-6, showing approximately $42-60\%$ toxicity, whereas much lower toxicity $(9-28\%)$ was observed at higher pH of 7-10, due to base-catalyzed hydrolysis of bensulfuron-methyl.

• Journal of The Korean Society of Grassland and Forage Science
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• v.33 no.3
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• pp.167-170
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• 2013

This study examined the growth performance and field evaluation of the dual herbicide-resistant transgenic creeping bentgrass plants. The effect of glyphosate treatment on the herbicide resistance of the transgenic creeping bentgrass plants was determined, and the non-transgenic control plant withered at the concentration $11{\mu}g/mL$ or higher whereas the transgenic creeping bentgrass plants survived the treatment at the concentration of $3,000{\mu}g/mL$, and the increase of the plant length was repressed as the glyphosate treatment concentration was increased. At field evaluation, glufosinate-ammonium and glyphosate were simultaneously treated to investigate the weed control effect. The results showed that more than 90% of the weeds withered four week after herbicide treatment, while the transgenic creeping bentgrass plants continued to grow normally. Therefore, the dual herbicide-resistant creeping bentgrass plants may be able to greatly contribute to the efficiency of weed control and to the economic feasibility of mowing in places such as golf courses.

• Applied Biological Chemistry
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• v.38 no.5
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• pp.440-446
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• 1995

In order to select the proper formulation of newly developed herbicide Cyhalofop-butyl{n-butyl-(R)-2-[4-(2-fluro-4-cyanophenoxy)phenoxy]propionte} to Echino-chloacrus-galli(L)P. Beaw. several formulations were made and tested by biological assay. Weed control of wettable powder formulated with two adjuvants on E. crus-galli showed higher effect as compared with the formulation made without adjuvants. Higher concentration of adjuvants resulted in higher absorption and higher weed control on E. crus-galli. However, adhesional force of wettable powder applied to leaf surface was not positively correlated to the amount of herbicide absorption. The weeding effect and amount of herbicide absorbed on E. crus-galli were higher by emulsifiable concentrateformulations with different HLB and non ionic surfactants as compared with wettable powder formulations. The higher adhesional force and higher absorption of herbicide on E. crus-galli were obtained from microemulsion than the others. Granulization of the herbicide with appropriate adjuvants in a form of resurfacing on the submerged water gave rise to a good weeding effect and believed to be a possible promising formulation.

• Journal of Microbiology and Biotechnology
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• v.22 no.2
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• pp.159-165
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• 2012

The rhizobacterial composition varies according to the soil properties. To test if the effect of herbicides on the rhizobacterial communities of genetically modified NK603 glyphosate-tolerant maize varies according to different soil locations, a comparison was made between the effects of glyphosate (Roundup Plus), a post-emergence applied herbicide, and a pre-emergence applied herbicide (GTZ) versus untreated soil. The potential effect was monitored by direct amplification, cloning, and sequencing of the soil DNA encoding 16S rRNA, and high-throughput DNA pyrosequencing of the bacterial DNA coding for the 16S rRNA hypervariable V6 region. The results obtained using three different methods to analyze the herbicide effect on the rhizobacterial communities of genetically modified NK603 maize were comparable to those previously obtained when glyphosate-tolerant maize was grown in soil with different characteristics. Both herbicides decreased the bacterial diversity in the rhizosphere, with Actinobacteria being the taxonomic group most affected. The results suggest that both herbicides affected the structure of the maize rhizobacterial community, but glyphosate was environmentally less aggressive.

• 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.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1999.06a
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• pp.21-38
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• 1999

Herbicide is an essential agricultural chemical in the modern agriculture. Due to its bioactivity, however, risk of herbicide use against non-target organisms should be seriously considered. Among the unfavorable aspects given by herbicide, the residue is the most important because herbicide residue in soil and agricultural product is closely related to human safety. The residue in soil and crop is dependent on conditions of soil, weather, herbicide use and crop cultivation, etc. In general, the residue in soil or agricultural product in Korea is known to be not serious at this moment, except for some problems like carry-over effect on succeeding crops. To secure safety of herbicide use for the health, soil ecology and other environment, researches on herbicide residue including monitoring survey should be done more frequently and extensively. Safety guide for herbicide usage should be kept by farmers and development of long toxic herbicide should be accelerated.

• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.2
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• pp.46-46
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• 1991

Adequate regrowth control of weeds and shrubs has been one of the important problem for pasture establishment by overseeding on reclaimed forest hilly land. This experiment was carried out on sloping shrub land near Anseong, Gyeonggido to evaluate the effects of herbicide application on growth control of native weeds, shrubs and trees. We evaluated 63 different weeds and wood species in the trials, which are grown common in korean forest. Buthidazol and 4 other herbicides (sodium chlorate, glyphosate, U-46 and gramoxone) were sprayed each at two application rates during the period of the most intensive growth, on 20 July 45 days before overseeding of pasture species. Glyphosate and sodium chlorate gave excellant control of growth of all species. However. Uncus effusus, Carex heterostachya, Polygonatum humile, Rubus corchorifolius, Lonicera coeralea and Rhododendron mucronulatum were classified as a tolerant weed and wood species to herbicides. Herbicide buthidazol showed also successive control of regrowth of weeds and wood species. But buthidazol was evaluated as a none available herbicide for use in pasture establishment. because o! their long persist of toxic herbicide residue in soils after treatments. Herbicide U-46 and gramoxone had almost no effect on regrowth of shrubs and tree species

• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.2
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• pp.76-83
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• 1991

Adequate regrowth control of weeds and shrubs has been one of the important problem for pasture establishment by overseeding on reclaimed forest hilly land. This experiment was carried out on sloping shrub land near Anseong, Gyeonggido to evaluate the effects of herbicide application on growth control of native weeds, shrubs and trees. We evaluated 63 different weeds and wood species in the trials, which are grown common in korean forest. Buthidazol and 4 other herbicides (sodium chlorate, glyphosate, U-46 and gramoxone) were sprayed each at two application rates during the period of the most intensive growth, on 20 July 45 days before overseeding of pasture species. Glyphosate and sodium chlorate gave excellant control of growth of all species. However. Juncus effusus, Carex heterostachya, Polygonatum humile, Rubus corchorifolius, Lonicera coeralea and Rhododendron mucronulatum were classified as a tolerant weed and wood species to herbicides. Herbicide buthidazol showed also successive control of regrowth of weeds and wood species. But buthidazol was evaluated as a none available herbicide for use in pasture establishment. because o! their long persist of toxic herbicide residue in soils after treatments. Herbicide 1:-46 and gramoxone had almost no effect on regrowth of shrubs and tree species.

• Journal of Microbiology and Biotechnology
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• v.11 no.1
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• pp.7-12
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• 2001

Three Pseudomonas strains (Bk8, Bk9, Bk10) selected from soil for their ability to degrade herbicide diuron were tested for their heavy metal resistance. The growth of these catabolic strains on a minimal medium with various concentrations of $Cd^{2+},\;Zn^{2+},\;Ni^{2+}$, and $Hg^{2+}$ revealed a minimal effect on the carbon source for the inhibitory effect of the metals. One of these strains, namely, Bk8, exhibited a high resistance to the heavy metals as compared to the two other strains. This strain harbors plasmid pBk8 (110 kb) and contains at least fur determinants encoding heavy metal resistance. Nickel and zinc resistance are encoded by genes located on the chromosome, while cadmium and mercury resistance are on plasmid pBk8. Accordingly, the characteristics of strain Bk8 suggest that it would be useful in the bioremediation of aromatic compounds in the presence of toxic heavy metals as co-contaminants.