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Web URL(s): | http://www.swss.ws/wp-content/uploads/docs/2010 Proceedings-SWSS.pdf#page=185 Last checked: 08/01/2013 Requires: PDF Reader Notes: Item is within a single large file |
Publication Type:
| Report |
Author(s): | Brosnan, J. T.;
Thoms, A. W.;
Breeden, G. K.;
Armel, G. R.;
Mueller, T. C.;
McCullough, P. E. |
Author Affiliation: | Brosnan, Thoms, Breeden, Armel and Mueller, University of Tennessee, Knowxville, TN; McCullough: University of Georgia, Griffin, GA |
Title: | Efficacy of flazasulfuron for control of annual bluegrass and perennial ryegrass as influenced by nitrogen |
Section: | Weed management in turf Other records with the "Weed management in turf" Section
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Meeting Info.: | Little Rock, Arkansas: January 25-27, 2010 |
Source: | 2010 Proceedings, Southern Weed Science Society. Vol. 63, 2010, p. 135. |
Publishing Information: | Champaign, Illinois: Southern Weed Science Society |
# of Pages: | 1 |
Keywords: | TIC Keywords: Application rates; Cynodon dactylon; Flazasulfuron; Herbicide efficacy; Herbicide evaluation; Lolium perenne; Nitrogen fertilization; Poa annua control; Sulfonylurea herbicides; Translocation
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Abstract/Contents: | "Flazasulfuron is a new sulfonylurea herbicide used to remove overseeded cool-season species from bermudagrass during spring transition. Field and laboratory studies were conducted in 2008 and 2009 evaluating the effects of nitrogen (N) fertilization on the efficacy of flazasulfuron for control of overseeded perennial ryegrass (Lolium perenne L.) contaminated with annual bluegrass (Poa annua L.). Field studies were conducted on mature bermudagrass (Cynodon dactylon) fairway at Egwani Farms Golf Course in Rockford, TN (2008 & 2009) and replicated at an additional location (University of Georgia Experiment Station; Griffin, GA) in 2009. At all locations, plots were arranged in a randomized complete block design with three replications. Treatments included flazasulfuron applied at 4.4, 8.8, and 17.5 g ha-1 alone, and in between sequential applications of N fertilizer (46-0-0) at 73 kg N ha-1. N fertilizer was applied granularly immediately prior to herbicide treatment and 4 weeks (wk) later. A non-ionic surfactant was included with all flazasulfuron treatments at a 0.25% v/v ratio. At both locations herbicide treatments were applied with CO2- powered backpack sprayers calibrated to deliver >280 L ha-1 of spray volume By 6 wk after treatment (WAT) in 2008, annual bluegrass control with flazasulfuron at 4.4, 8.8, and 17.5 g ha-1 was improved 73, 59, and 35% by two applications of N at 73 kg N ha-1. In both years, the level of annual bluegrass control following treatment with flazasulfuron at 4.4 g ha-1 and N at 73 kg N ha-1 was greater than that which was achieved following treatment with flazasulfuron at 17.5 g ha-1 alone. Improvements in perennial ryegrass control due to applications of N were less substantial than those observed for annual bluegrass, as perennial ryegrass control by 3 WAT in 2009 following treatment with flazasulfuron at 4.4, 8.8, and 17.5 g ha-1 was only improved 18, 11, and 9% by application of N at 73 kg N ha-1. Annual bluegrass plants were harvested from the same TN location used for the field study and thinned to one tiller. Plants were transplanted into a peat moss growing medium and placed in a growth chamber (Knoxville, TN) configured to provide a 12/9 C day/night temperature and a 12 h photoperiod. After a 3 wk acclimation period, plants were divided into two groups. The first group received an application of N at 73 kg N ha-1 and a broadcast application of flazasulfuron at 8.8 g ha-1 mixed with a non-ionic surfactant at a 0.25% v/v ratio, while the second group only received a broadcast application of flazasulfuron and non-ionic surfactant at the same rates as the first. A single 1 μL droplet of a radioactive solution containing 35 μL 14C-flazasulfuron (specific activity, 4.18 MBq/mg; radiochemical purity 94%) stored in acetonitrile, 64 μL of distilled H20, and 2.5 μL of non-ionic surfactant was applied to the adaxial surface of the first subtending leaf from the budleaf. Each 1 μkL droplet of radioactive solution delivered approximately 5 kBq of 14C-flazasulfuron to the treated leaf of each plant. Non-absorbed 14C-flazasulfuron was quantified by excising the treated leaf and rinsing it in 5 ml of a 50:50 methanol:water solution at 1, 4, 8, 24, 48, and 72 hours after treatment (HAT). Rinsate was analyzed using liquid scintillation spectrometry (LSS). Immediately after rinsing the treated leaf of each sample, plants were removed from the growing medium and divided into three: treated leaf, shoot tissue other than the treated leaf, and root tissue. Tissues were weighed and combusted in a sample oxidizer configured to trap evolved 14CO2 using a carbon dioxide absorbent. This solution was analyzed using LSS to determine the distribution of radioactivity over time. Significant differences in foliar absorption of 14C-flazasulfuron due to N fertility were not detected. However, treatment with N fertilizer at 73 kg N ha-1 increased translocation of 14C-flazasulfuron (and any potential metabolites) from the treated leaf to other shoot tissues by 18% at 1 HAT and 22% at 4 HAT compared to plants not treated with N fertilizer. This increase in translocation may explain the increased level of annual bluegrass control observed in the field." |
Language: | English |
References: | 0 |
Note: | This item is an abstract only! |
| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete): Brosnan, J. T., A. W. Thoms, G. K. Breeden, G. R. Armel, T. C. Mueller, and P. E. McCullough. 2010. Efficacy of flazasulfuron for control of annual bluegrass and perennial ryegrass as influenced by nitrogen. South. Weed Sci. Soc. Proc. 63:p. 135. |
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| Web URL(s): http://www.swss.ws/wp-content/uploads/docs/2010 Proceedings-SWSS.pdf#page=185 Last checked: 08/01/2013 Requires: PDF Reader Notes: Item is within a single large file |
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