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| Web URL(s): | http://www.swss.ws/wp-content/uploads/docs/2009 Proceedings-SWSS.pdf#page=90
Last checked: 07/25/2013
Requires: PDF Reader
Notes: Item is within a single large file |
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| Publication Type:
| Report |
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| Author(s): | Flessner, M. L.;
McElroy, J. S.;
Walker, R. H. |
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| Author Affiliation: | Auburn Univ., Auburn, AL |
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| Title: | Quantification of warm-season turfgrass phytotoxcity from broadleaf control herbicides |
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| Section: | SWSS M. S. poster contest
Other records with the "SWSS M. S. poster contest" Section
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| Meeting Info.: | Orlando, Florida: February 9-12, 2009 |
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| Source: | 2009 Proceedings, Southern Weed Science Society. Vol. 62, 2009, p. 20. |
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| Publishing Information: | Champaign, Illinois: Southern Weed Science Society |
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| # of Pages: | 1 |
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| Keywords: | TIC Keywords: Aminocyclopyrachlor; Application rates; Broadleaf weed control; Cultivar evaluation; Cynodon dactylon x Cynodon transvaalensis; Herbicide evaluation; Herbicide injury; Photosystem II; Phytotoxicity; Stenotaphrum secundatum; Auxins; Triclopyr; Zoysia japonica X Zoysia tenuifolia
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| Cultivar Names: | Emerald; Palmetto; TifSport |
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| Trade Names: | Turflon Ester |
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| Abstract/Contents: | "Synthetic auxin herbicides effectively control broadleaf weeds in many turfgrass species; however, phytotoxicity to warm-season turfgrasses has been observed. Injury quantification related to herbicide rate is necessary to determine the cause and extent of phytotoxicity to warm-season turfgrasses from auxinic herbicides. Research was conducted quantifying injury from triclopyr and DPX-KJM44-044 (aminocyclopyrachlor; proposed common name), which is a synthetic auxin type herbicide being developed by the el du Pont de Nemours and Company (Dupont Company; Wilmington, DE) for right-of-way and non-crop broadleaf weed control. Aminocyclopyrachlor and triclopyr were applied to 'Tifsport' bermudagrass (Cynodon dactylon x C. transvaalensis), 'Palmetto' St. Augustinegrass (Stenotaphrum secundatum), and 'Emerald' zoysiagrass (Zoysia japonica x Z. tenuifolia). Two inch plugs were taken from mature turfgrass stands at the Auburn University Turfgrass Research Unit in Auburn, Alabama. Turfgrass plugs were placed in 3.5 inch diameter pots with native soil in the greenhouse and allowed to adjust and acclimate to the greenhouse environment for 4 weeks. Grasses were then treated via a single Tee Jet 8002EV nozzle in a spray chamber using compressed air as propellant and calibrated at 90 GPA. Pots were arranged in a randomized complete block design with 4 replications. Grasses were mowed with a rotary mower at a height of 1.75 inches two times per week. Ratings (visual, fluorometric, and digital images) were taken at 3 days after treatment, 1, 2, 3, 4, 6, and 8 weeks after treatment (WAT). Treatments included triclopyr (Turflon Ester 4EC, Dow AgroSciences, Indianapolis, IN) at 0.375, 0.75, 1.5, 3.0, 6.0, 12.0, and 24.0 lb ai/A and aminocyclopyrachlor (80% WDG) at 0.3, 0.6, 1.2, 2.4, 4.8, 9.6, and 19.2 oz ai/A in addition to a nontreated check. Fluorometer (fv/fm) measurements were used to determine photosystem II efficiency of the treated turfgrasses. Efficiency of 60-70% is considered peak efficiency, corresponding to healthy turfgrass. Efficiency of less than 50% is characteristic of a damaged photosystem. Visual turf quality ratings were based on a scale of 1-9 with 1 corresponding to dead or non-existent turfgrass, 7 corresponding to optimal, healthy turfgrass, and 9 corresponding to superior turfgrass. A quality rating of <=5 is considered unacceptable. Digital images were taken to determine percent cover of the treated turfgrasses. Images were taken in a controlled lighting environment and evaluated for percent green cover using Sigma Scan software (http://www.aspiresoftwareintl.com/html/sigmascan pro.html; http://turf.uark.edu/turfmacro/). Any reduction in percent green cover is considered unacceptable. Data was subjected to ANOVA treatment with means separated by LSD at the 0.05 significance level. Turf quality, green cover, and photochemical efficiency decreased as herbicide rate increased. Aminocyclopyrachlor >=0.6 oz ai/A and >=1.2 oz ai/A reduced St. Augustinegrass and bermudagrass turf quality unacceptably (<5) at 4 WAT. Aminocyclopyrachlor >=2.4 oz ai/A reduced zoysiagrass turf quality to <5 at 6 WAT. Aminocyclopyrachlor reduced green cover of St. Augustinegrass unacceptably at all rates, bermudagrass at >=0.6 oz ai/A, and zoysiagrass at >=4.8 oz ai/A at 4 WAT. Aminocyclopyrachlor at 0.6 oz ai/A and 4.8 oz ai/A reduced St. Augustinegrass green cover to 23% and zoysiagrass green cover to 65% at 4 WAT. Aminocyclopyrachlor >=0.6 oz ai/A reduced St. Augustinegrass photochemical efficiency from 73% in the control to 50% at 4 WAT. Aminocyclopyrachlor <=2.4 oz ai/A did not decrease bermudagrass photochemical efficiency at all rating dates. Aminocyclopyrachlor at 19.2 oz ai/A reduced zoysiagrass photochemcial efficiency to <40% from 70% in the control at 6 WAT. Triclopyr at all rates caused unacceptable St. Augustinegrass and bermudagrass turf quality reduction at 4 WAT. Triclopyr >=3.0 lb ai/A caused zoysiagrass turf quality to be reduced to 5 at 6 WAT. Triclopyr at all rates reduced St. Augustinegrass and bermudagrass green cover at 4 WAT. Triclopyr >=3.0 lb ai/A reduced percent green cover of zoysiagrass by 20% at 4 WAT. Triclopyr at all rates reduced St. Augustinegrass and bermudagrass photochemcial efficiency at 4 WAT. Triclopyr >=12.0 lb ai/A reduced zoysiagrass photochemical efficiency by 20% at 6 WAT. Bermudagrass was the only turfgrass tested to recover during the study; percent green cover recovery was observed at 6 and 8 WAT from aminocyclopyrachlor <=6.0 oz ai/A and from triclopyr <=0.75 lb ai/A. Overall, zoysiagrass is the most tolerant to the herbicides tested. St. Augustinegrass and bermudagrass were similarly tolerant to triclopyr. St. Augustinegrass was the least tolerant of aminocyclopyrachlor. Triclopyr was more injurious than aminocyclopyrachlor to warm-season turfgrasses - as comparing relative label use rates." |
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| Language: | English |
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| References: | 0 |
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| Note: | This item is an abstract only! |
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| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Flessner, M. L., J. S. McElroy, and R. H. Walker. 2009. Quantification of warm-season turfgrass phytotoxcity from broadleaf control herbicides. South. Weed Sci. Soc. Proc. 62:p. 20. |
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| Web URL(s):
http://www.swss.ws/wp-content/uploads/docs/2009 Proceedings-SWSS.pdf#page=90
Last checked: 07/25/2013
Requires: PDF Reader
Notes: Item is within a single large file |
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