Weed Control Efficacy and Citrus Response to Flazasulfuron Applied Alone or in Combination with Other Herbicides

Megh Singh, Analiza H. M. Ramirez, Amit J. Jhala, Mayank Malik

Citrus Research and Education Center, Horticultural Sciences Department, Institute of Food and Agricultural Sciences (IFAS), Uni-versity of Florida, Lake Alfred, USA.
Monsanto Corp., Lincoln, USA.

DOI: 10.4236/ajps.2012.34062                

Abstract

Field experiments were conducted to evaluate the phytotoxicity of flazasulfuron on citrus species and efficacy on weeds when applied alone or in combination with other herbicides. Grapefruit was the most sensitive and tangerine was the least sensitive to flazasulfuron. Injury to grapefruit was 70% with the application of flazasulfuron at 0.20 kg a.i. ha^–1 at 60 DAT and was reduced (5%) when flazasulfuron at 0.05 kg a.i. ha^–1 was tank mixed with glyphosate at 0.84 kg·a.i.· ha^–1. Flazasulfuron alone at all rates did not control grass weeds and common ragweed. Florida/Brazil pusley was moderately controlled with high rates of flazasulfuron from 30 to 45 DAT; however, control did not exceed 75%. There was good control of Spanishneedles (78% - 85%) and horseweed (73% - 81%) with flazasulfuron at all rates at 30 DAT but control declined later in the season. Tank mix of flazasulfuron with glyphosate improved flazasulfuron efficacy on grass and broadleaf weeds. Flazasulfuron at 0.07 kg a.i. ha^–1 plus glyphosate at 1.70 kg a.i. ha^–1 was more effective in controlling grass weeds (83%) at 60 DAT and provided the highest control (79%) of Florida/Brazil pusley at 45 DAT. There was excellent control (75% to 94%) of Spanishneedles and adequate control of eastern black nightshade and common ragweed with flazasulfuron tank mixed with glyphosate or diuron. This study showed that flazasulfuron alone does not adequately control grasses and some broadleaf weeds in citrus and tank mixing it with glyphosate or diuron improved flazasulfuron’s efficacy. However, injury to grapefruit was observed at rates which effectively controlled weeds. Further studies are needed to determine the most suitable flazasulfuron rate that could be used to manage weeds in grapefruit.

Keywords

Chemical Weed Control; Crop Safety; Diuron; Glyphosate

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	National Agricultural Statistics Service (NASS), “Florida Citrus Statistics 2009-2010.” 2011. http://www.nass.usda.gov/statistics_bystate/Florida/publications/citrus/fcs/2009-10/fcs0910.pdf
[2]	T. M. Spann, R. A. Atwood and J. Yates, “Dooryard Citrus Production: The Value of the Florida Citrus Industry to Florida Residents,” 2008, Horticultural Sciences Department, Florida Cooperative Extension Service, UF/ IFAS, Gainesville, 2011. http://www.edis.ifas.ufl.edu/hs381
[3]	M. Singh and S. D. Sharma, “Benefits of Triazine Herbicides and Other Weed Control Technology in Citrus Management,” In: H. M. Lebaron, J. E. McFarland and O. C. Burnside, Eds., The Triazine Herbicides—50 Years Revolutionizing Agriculture, Elsevier, San Diego, 2008, pp. 199-209.
[4]	S. H. Futch and M. Singh, “2011 Florida Citrus Pest Management Guide: Weeds,” In: M. E. Rogers, M. M. Dewdney and T. M. Spann, Eds., 2011 Florida Citrus Pest Management Guide, University of Florida, IFAS, Gainesville, 2011, pp. 139-151.
[5]	S. D. Sharma and M. Singh, “Effect of Timing and Rates of Application of Glyphosate and Carfentrazone Herbicides and Their Mixtures on the Control of Some Broad-leaf Weeds,” HortScience, Vol. 42, No. 5, 2007, pp. 1221-1226.
[6]	I. Heap, “International Survey of Herbicide Resistant Weeds,” 2011. http://www.weedscience.org
[7]	R. S. Chandran and M. Singh, “Survey and Control of Brazil Pusley (Richardia brasiliensis) in Florida Citrus,” Proceedings of the Florida State Horticultural Society, Vol. 116, 2003, pp. 211-214.
[8]	M. D. Grove, “An Update on the Pending New Registrations of Flazasulfuron in the United States,” Proceedings of the Weed Science Society of America, Vol. 64, 2011, p. 196.
[9]	Anonymous, “Flazasulfuron Wide Spectrum Herbicide,” 2011. http://www.iskweb.co.jp/products/pdf/flazasulfuron.pdf
[10]	B. J. Brecke and J. B. Unruh, “Weed Management in Warm Season Turfgrass with CGA 362622,” Proceedings of the Southern Weed Science Society, Vol. 55, 2002, p. 52.
[11]	J. B. Beam, W. L. Baker and S. D. Askew, “Efficacy of Flazasulfuron for Weed Control in Bermudagrass,” Proceedings of the Southern Weed Science Society, Vol. 57, 2004, p. 121.
[12]	L. S. Warren and F. H. Yelverton, “Viola Species Control Using Sulfonylurea Herbicides,” Proceedings of the Southern Weed Science Society, Vol. 57, 2004, p. 94.
[13]	M. J. Taylor, J. D. Byrd, K. C. Hutto and D. W. Wells, “Winter Weed Control with ALS-Inhibiting Herbicides in Bermudagrass Turfgrass,” Proceedings of the Southern Weed Science Society, Vol. 58, 2005, p. 106.
[14]	K. C. Hutto, B. J. Brecke and J. B. Unruh, “Comparison of Flazasulfuron to Pyridine Herbicides for Virginia Buttonweed (Diodia virginiana) Control,” Weed Technology, Vol. 22, No. 2, 2008, pp. 351-353. doi:10.1614/WT-07-062.1
[15]	J. T. Brosnan, A. W. Thomas, P. E. McCullough, G. R. Armel, G. J. Breeden, J. C. Sorochan and T. C. Mueller, “Efficacy of Flazasulfuron for Control of Annual Bluegrass (Poa annua) and Perennial Ryegrass (Lolium perenne) as Influenced by Nitrogen,” Weed Science, Vol. 58, No. 4, 2010, pp. 449-456. doi:10.1614/WS-D-09-00019.1
[16]	D. W. Wells, J. M. Taylor, J. D. Byrd, Jr. and K. C. Hutto, “Virginia Buttonweed Control with ALS-Inhibiting Herbicides Applied Alone and with Trimec Classic,” Proceedings of the Southern Weed Science Society, Vol. 57, 2004, p. 106.
[17]	K. C. Hutto, B. J. Brecke and J. B. Unruh, “Flazasulfuron for Chamberbitter Control in Turfgrass,” Proceedings of the Southern Weed Science Society, Vol. 59, 2006, p. 105.
[18]	F. H. Yelverton, T. W. Gannon, J. D. Hinton and L. S. Warren, “Weed Control and Turfgrass Tolerance to Flazasulfuron,” Proceedings of the Southern Weed Science Society, Vol. 56, 2003, p. 101.
[19]	B. J. Brecke, B. Unruh and D. P Telenko, “Flazasulfuron for Weed Management in Warm-Season Turfgrass,” Proceedings of the Southern Weed Science Society, Vol. 62, 2009, p. 398.
[20]	J. B, Willis, D. B. Ricker and S. D. Askew, “Sulfonylurea Herbicides Applied During Early Establishment of Seeded Bermudagrass,” Weed Technology, Vol. 21, No. 4, 2007, pp. 1035-1038. doi:10.1614/WT-07-058.1
[21]	M. J. Goddard, S. D. Askew, J. B. Willis and M. B. Grove, “Flazasulfuron: A Potential Solution for Selective Perennial Ryegrass Control in Creeping Bentgrass,” Proceedings of the Northeast Weed Science Society, Vol. 61, 2007, p. 25.
[22]	A. F. Senasac and I. Tsonakis-Bradley, “Weed Management Research in Ornamentals, Turfgrass, Vegetables and Fruits,” 2009 Research Summary, Cornell University Cooperative Extension of Suffolk County, Riverhead, New York, 2011. http://www.ccesuffolk.org/assets/weed-science/documents/weed-mgmt-res-cucesc-2009.pdf
[23]	E. B. Durigan-Marcel, J. C. Durgan and M. Gustavo, “Selectivity of the Herbicide Flazasulfuron Applied after Postemergence in Sugarcane (Saccharum spp. L.) Crop,” Journal of Environmental Science and Health, Vol. 40, No. 1, 2005, pp. 177-180.
[24]	T. K. James, A. Rahman and P. De Jong, “Flazasulfuron for Control of Ragwort (Senecio jacobeae) in Pasture,” Proceedings of the 50th New Zealand Plant Protection Conference, 1997, pp. 477-481. http://www.nzpps.org/journal/50/nzpp_504770.pdf
[25]	B. J. Brecke, K. C. Hutto and J. B. Unruh, “Postemergence Southern Crabgrass (Digitaria cilliaris) Control with Sulfonylurea Herbicides,” Weed Technology, Vol. 22, No. 2, 2008, pp. 354-358. doi:10.1614/WT-07-063.1
[26]	D. W. Wells, R. H. Walker and J. L. Belcher, “Effects of Imazapic and Flazasulfuron on Dallisgrass in Bermudagrass Turf,” Proceedings of the Southern Weed Science Society, Vol. 62, 2009, p. 88.
[27]	J. B, Willis, D. B. Ricker and S. D. Askew, “Riviera Bermudagrass Response to Pre-Seeding Applications of Sulfonylurea Herbicides,” Applied Turfgrass Science, 2011. http://www.plantmanagementnetwork.org/pub/ats/research/2008/riviera
[28]	F. H. Yelverton and L. S. Warren, “Postemergence Common Lespedeza Control Using Flazasulfuron Combinations,” 2007 Turfgrass Research Report: Weed Control and PGR’s, Crop Science Department, North Carolina State University, Raleigh.
[29]	J. Boyd, “Common Lespedeza Control in Cavalier Zoysiagrass,” Arkansas Turfgrass Report 2008, Arkansas Agricultural Experiment Station Research Service, Vol. 568, 2009, pp. 9-11.
[30]	S. D. Askew, M. J. Goddard and J. B. Willis, “Herbicide Combinations with Flazasulfuron for Broad Spectrum Weed Control in Creeping Bentgrass,” Proceedings of the Southern Weed Science Society, Vol. 62, 2009, p. 397.