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| Publication Type:
| Report |
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| Author(s): | Flint, J. L.;
Barrett, M.;
Olson, G. L. |
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| Author Affiliation: | University of Kentucky |
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| Title: | Interaction of 2,4-D or dicamba with glyphosate on Johnsongrass |
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| Source: | Kentucky Turfgrass Research. 1985, p. 29. |
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| Publishing Information: | Lexington, KY: University of Kentucky, College of Agriculture, Cooperative Extension Service |
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| Keywords: | TIC Keywords: Glyphosate; Herbicide interaction; Application rates; Antagonism; Herbicides; Sorghum halepense; Dicamba; 2,4-D
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| Geographic Terms: | Kentucky |
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| Abstract/Contents: | Previous research has indicated reduced grass control when glyphosate is applied in combination with 2,4-D or dicamba. The objectives of these studies were to repeat and charaterize previously observed antagonism with johnsongrass and establish a basis for the antagonism. Field research was conducted in Richmond, Kentucky during 1985. Treatments consisted of glyphosate at 0.56, 1.1, and 1.7 kg/ha applied alone and in combination with the dimethylamine salts of 2,4-D and dicamba at 0.28, 0.56, 0.84, and 1.1, and 1.7 salts of 2,4-D and dicamba at 0.28, 0.56, 0.84, and 1.1 kg/ha. Treatments were applied when johnsongrass reached a height of 45 to 55 cm. Visual observations and biomass data were collected at 4 weeks after treatment (WAT). Plots were then mowed and evaluated 8 WAT for percent regrowth. Results collected 4 and 8 WAT indicated antagonism where the lower rate of glyphosate was with higher glyphosate rates. Upon completion of the field study, a greenhouse rate response study was initiated to repeat the observed antagonism. Treatments consisted of glyphosate at 0.28, 0.56, 0.84 and 1.12 kg/ha applied alone and in combination with dimethylamine salts of 2,4-D and dicamba at 0.14, 0.28, 0.42, and 0.56 kg/ha. Treatments were applied when seedling johnsongrass reached a height of 45 cm. MON 0818 surfactant (0.5% v:v) was added to each of the 2,4-D and dicamba alone treatments. Root fresh weights collected 4 WAT indicated no response to 2,4-D or dicamba alone. Both 2,4-D and dicamba caused antagonism of glyphosate activity at the low glyphosate rate. This antagonism was counteracted at the higher rates of glyphosate. Uptake and translocation studies were conducted to explain the basis for the observed antagonism. C14-glyphosate was applied to the third fully expanded leaf at 0.28 and 0.84 kg/ha alone and in combination with 2,4-D or dicamba acids at 0.28 and approximated field use rates and contained 0.5% (v:v) MON 0818. Results indicated the combination of 2,4-D or dicamba with glyphosate reduced glyphosate uptake. Translocation data did not explain the antagonism. |
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| Language: | English |
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| References: | 0 |
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| See Also: | Other items relating to: 2, 4 - D in Turf |
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| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Flint, J. L., M. Barrett, and G. L. Olson. 1985. Interaction of 2,4-D or dicamba with glyphosate on Johnsongrass. KY. Turfgrass Res. p. 29. |
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