• Korean Journal of Environmental Agriculture
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• v.27 no.1
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• pp.86-91
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• 2008

Dicamba(3,6-dichloro-2-methoxybenzoic acid) is used to control for pre and post-emergence of annual and perennial broad-leaf weeds. It is very soluble in water and highly mobile, acidic herbicide. So it is easily moved and detected in groundwater. Zerovalent iron(ZVI) has been used for the reductive degradation of certain compounds through amination of nitro-substituted compounds and dechlorination of chloro-substituted compounds. In this study, we investigated the potential of ZVI for the oxidative degradation of dicamba in water. The degradation rate of dicamba by ZVI was more rapidly increased in pH 3.0 than pH 5.0 solution. The degradation percentage of dicamba was increased with increasing amount of ZVI from 0.05% to 1.0%(w/v) and reached above 90% within 3 hours of reaction. As a result of identification by GC-MS after derivatization with diazomethane, we obtained three degradation products of dicamba by ZVI. They were identified 4-hydroxy dicamba or 5-hydroxy dicamba, 4,5-dihydroxy dicamba and 3,6-dichloro-2-methoxyphenol. 4-Hydroxy dicamba or 5-hydroxy dicamba and 4,5-dihydroxy dicamba are hydroxylation products of dicamba. 3,6-dichloro-2-methoxyphenol is hydroxyl group substituted compound instead of carboxyl group in dicamba. We also confirmed the same degradation products of dicamba in the Fenton reaction which is one of oxidation processes using ferric sulfate and hydrogen peroxide. But we could not find out the dechlorinated degradation products of dicamba by ZVI.

• The Korean Journal of Pesticide Science
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• v.2 no.1
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• pp.53-58
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• 1998

In order to minimize harmful side effects, extend weed control performance, and control the releasing rate of the active ingredient, dicamba controlled release granular formulations were prepared with starch as matrix. Leaching, soil residue, and volatilization of the granules were compared with dicamba soluble concentrate formulation (SL). Leaching of dicamba through the soil applied with the granules could be reduced more than 50% as compared with that of dicamba SL. The half life of dicamba in loamy soil treated with the granules was 50 to 51 days, while that in sand loamy soil was 50 to 58 days. Whereas, the half life of dicamba in loamy and sand loamy soil applied with dicamba SL was 24 and 22 days, respectively. Volatilization of dicamba from the granules was 10 times less than that of dicamba SL.

• The Korean Journal of Pesticide Science
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• v.4 no.3
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• pp.1-6
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• 2000

In order to elucidate the degradation of the herbicide dicamba, the degradabilities of dicamba under sunlight and in soils were investigated. The photodegradation rate of the authentic dicamba under sunlight condition was only 3.3% after 9 weeks. 4-Hydroxy dicamba turned out to be the major product, and 5-hydroxy dicamba was also identified. Dicamba was degraded to 3,6-dichlorosalicylic acid by demethylation in the viable soil, which resulted in 14.7 to 23.2% degradation of the applied amount during 8 weeks of incubation. Meanwhile, the degradation was quite slow in the sterilize soil, which revealed that the soil microbes played a major role in dicamba degradation.

• The Korean Journal of Pesticide Science
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• v.4 no.4
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• pp.26-30
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• 2000

Degradabilities of the dicamba by microorganisms isolated from soil and by enzymes in the turfgrass, Zoysia Japonica S. were investigated. Five species of dicamba-deading microorganisms including Acidovorax sp., Alcaligenes sp., and Variovorax sp. were isolated from soils by enrichment culture. All strains in nutrient-free inorganic medium treated with 10 ppm of dicamba degraded average 90% of the dicamba 21 days after incubation. 5-Hydroxydicamba, major metabolite, was detected from the culture broth. The half life of dicamba in the phosphate buffer extracts of Zoysia Japonica S. was 2.5 to 2.7 days. Trace amounts of 4- and 5-hydroxydicamba were detected in the extracts.

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.2
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• pp.150-156
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• 1997

This study was carried out to investigate the effects of herbicide treatment on the forage yield, nutrient productivity, weed control and persistency in the Rumex crispus dominated pasture in Suwon and in Youngam kom June, 1993 to October, 1995, respectively. It was arranged as a randomized block design with five treatments : 1. reseeding at middle August, 2. dicamba 2liter /ha+reseeding at early July, 3. dicamba 24liter ha+reseeding at middle August, 4.dicamba 2lliter /ha+reseeding at early July +dicamba 14 /ha and 5.dicamba 24liter /ha +reseeding at middle August +dicamba 1liter/ha. In the Rumex crispus dominated pasture, the treatments of dicamba 2liter ha+reseeding(early July or middle August)+dicarnba 1liter/ha were controlled 77-92% of the weed, and increased 105- 141% of forage yield and were higher 88-141% of energy (TDN and NEL) productivity compared with reseeding at middle August (control), respectively. The results indicated that herbicide treatment was effective for the control of Rumex crisps and renovation of grassland, and higher forage yield could be obtained by twice applications of dicamba.

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.3
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• pp.277-284
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• 1997

With a purpose of finding out the influences of herbicide treatment method on the forage yield, nutrient productivity, weed control, and persistency in the Rumex acetosella dominated pasture, this trial was arranged as a randomized block design with six treatments[1.Seeding(control), 2. Lime+seeding 3. glyphosate 4 $\scr{l}$ + dicamba 2 $\scr{l}$ /ha+seeding 4. glyphosate 4$\scr{l}$ +dicamba 2$\scr{l}$ /ha+lime+seeding 5. glyphosate 4$\scr{l}$ +dicamba 21 / ha+seeding+dicamba 4 $\scr{l}$ /ha and 6. glyphosate 4 $\scr{l}$ +dicamba 2 $\scr{l}$ /ha+ lime+ seeding+dicamba 4 $\scr{l}$ /ha], and conducted in Hwasung Kyonggi Province and in Youngam, Jeonnarn Province from June, 1992 to October, 1995. In the Rumex acetosella dominated pasture, the treatments of glyphosate 4$\scr{l}$ +dicamba 21 /ha+lime+ seeding+dicamba 4 $\scr{l}$/ha controlled 88-98% of the weed (Rumex acetosella), increased 88- 173% of forage yield, and were high 82- 175% of energy (TDN and NEL) productivity than those of the control(seeding), respectively. The results of this study indicated that herbicide treatment was effective for the control of Rumex acetosella, and good renovation of grassland and higher DM yield of forage could be obtained by twice application of glyphosate 4 $\scr{l}$+ dicamba 2 $\scr{l}$ /ha and dicamba 4 $\scr{l}$ /ha.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.3
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• pp.259-264
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• 1999

A field experiment was carried out to determine the optimum application level of dicamba herbicide for efficient control of Calystegia japonica in silage corn field. Six treatments of application levels (0 ; control, $0.75{\ell},\;1.0{\ell},\;1.25{\ell},\;1.5{\ell},\;and\;2.0{\ell}/ha$) were arranged at National Livestock Research Institute, RDA, Suwon in 1995. The hybrid silage corn was DK 729, and dicamba herbicide was applied at 5~6 leaf stage of corn. The growth of corn was poor in control plot, and the days for tasseling and silking were delayed 1~4 days when compared with the plots of herbicide application. The control efficiency of Calystegia japonica was excellent as 74.3~94.6% in the plots of dicamba application. A slight injury of herbicide was observed at early stage of corn when applied at $1.25{\ell}$ and $1.5{\ell}$ of dicamba per ha, and severe injury was found at $2.0{\ell}$ of dicamba. Forage dry matter(DM) yield, and length of ear in the plots of dicamba treatments were significantly higher than those of control. The DM yield of control(4,866kg/ha) was only about 30% of dicamba treatment plot (14,960~16,340kg/ha). However, there was no yield difference among dicamba application level. The percentage of ear to total DM yield was ranged from 33.6 to 39.4%. With application of herbicide, the contents of crude protein and nitrogen free extract were increased, and that of crude fiber was decreased in stover. However, nutritive value of corn ear was very similar among all treatments, regardless of herbicide treatment. From the above results, it is recommended that optimum application level of dicamba herbicide was $0.75{\sim}1.0{\ell}/ha$ for efficient control of Calystegia japonica and for silage corn production without herbicide injury.

• The Korean Journal of Pesticide Science
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• v.3 no.1
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• pp.37-45
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• 1999

Dicamba (3,6-dichloro-o-anisic acid) granular formulations for controlled release (DGFCRs) were prepared with biodegradable polymers, corn starch and pregelatinized starch, to minimize harmful side effects, extend weed control performance, and control the releasing rate of the active ingredient. Physico-chemical properties and biological activity of DGFCRs were studied. Six different granules were formulated by applying two processes, granulation and extrusion. Formulation efficiencies of active ingredient (A.I.) in the granules prepared by granulating and extruding were $90.0{\sim}96.3%$. Incorporation ratios of A.I. in the granules prepared by granulating and extruding showed $89.5{\sim}94.5%$ and $46.7{\sim}82.0%$, respectively. The highest swellability was DG-2 formulation prepared with corn starch. Whereas, the lowest floatability in water was DG-2 formulation, while the highest one was DG-1 formulation prepared with pregelatinized starch, Miragel 463. The degradation rates of dicamba in the granules under the elevated temperature of $50^{\circ}C$ were less than 5% for DG-1 and DG-2 formulations even after 90 days, meanwhile, those of DE-1 formulations prepared with pregelatinized starch, Mirasperse, were more than 5%. The release rates of A.I. from the granules into water under a static condition were about 100% after 2 weeks. Weeding effects of the granules on broad leaf weeds tested in greenhouse were more than 90% after 30 days.

• Journal of Environmental Health Sciences
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• v.23 no.3
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• pp.72-79
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• 1997

본 실험은 제초제인 2,4-D, dicamba, 및 MCPP의 토양에서의 이동을 확인하고 평가하기 위하여 토양종류에 따른 이들 제초제의 흡착과 휘발을 일정시간 동안 조사하였다. 제초제의 토양중 흡착은 batch isotherm으로 조사하였는데, MCPP와 2,4-D는 Freundlich식에서 직선으로 나타났으며, dicamba는 곡선으로 나타났다. Silty clay 토양에서 MCPP의 K$_d$ 및 K$_{fr}$값이 가장 높았으며, loamy sand 토양에서는 dicamba의 K$_d$, K$_{fr}$값이 가장 낮았다. 전반적으로 silty clay 토양에서 K$_d$, K$_{fr}$값이 높았고 N값은 낮았다. 토양에 살포된 제초제의 약 40%가 처리 25일 경과시 휘발되거나 분해되었으며, 이들 제초제중 2,4-D가 dicamba와 MCPP에 비하여 분해 및 휘발속도가 빨랐다. 모든 토양에서 이들 제초제의 분해 및 휘발속도는 공기에 노출된 초기에 현저하게 빠른 것으로 나타나고 있다. 본 연구의 결과는 자연환경중에서 이들 제초제의 이동 및 잔류 현황을 예견하는데 사용될 수 있을 것으로 사료된다.

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.4
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• pp.351-356
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• 1997

With a purpose of finding out the influences of herbicide treatment on the forage value and ecological characteristics of grassland vegetations in the Rumex acetosella dominated pasture, this trial was arranged as a randomized block design with three treatments[1) Seeding(cntrol), 2)dicamba 4${\ell}$/ha+seeding+dicamba 4 ${\ell}$/ha and 3) dicamba 4${\ell}$/ha+lime+seeding+dicamba 4 ${\ell}$/ha], and conducted in Youngam, Jeonnam Province ftom June, 1995 to October, 1996. In the Rumex acetosella dominated pasture, the treatment of dicamba 4${\ell}$/ha+ lime+seeding+dicamba 4${\ell}$/ha was improved to the most desirable grassland vegetation with pasture plants of 87%. In the renovated grassland, the life forms of Hemicryptophytes increased greatly by 57.0%, on the other hand Geophytes was much more decreased by 56.8% than those of low productive grassland. The similarity coefficients between grassland vegetation groups were greatly affected by botanical composition. The forage value of standing crop in the renovated grassland with 6.56 was much more increased than low productive grassland with 2.76. The treatment of dicamba 4${\ell}$/ha+lime+ seedingdicamba 4${\ell}$/ha increased 2 1% of dry mattaer yield, and were high 18- 19% of energy (NEL and TDN) productivity than those of the control(seeding), respectively.