Response of Grapes to 2,4-D, Dicamba, and Glyphosate Simulated Drift Thesis Presented in Partial Fulfillment of the Requirements for the Degree Master of Science in the Graduate School of The Ohio State University By Scott James Wolfe, B.A. Graduate Program in Horticulture and Crop Science The Ohio State University 2013 Thesis Committee: Douglas Doohan, Advisor Joshua Blakselee Mark Loux Copyright by Scott James Wolfe 2013 Abstract In the USA, herbicides are widely used as an integral tool for weed management. With genetically modified crops such as Roundup Ready® (glyphosate-resistant) corn and soybean, herbicides that normally would have killed a crop can be used for weed control. Over years of use, some weed species have developed resistance to glyphosate and require novel approaches to management. New technologies, including 2,4-D and dicamba resistant crops, are one approach for corn and soybean farmers to better manage weeds; however, vapor or particle drift of these herbicides can damage sensitive crops such as grapes, tomatoes, and peppers. Research over the last 30 or more years has shown some of the effects of these herbicides on sensitive crops. With the impending introduction of new resistance traits in agronomic crops, the use of 2,4-D and dicamba will likely increase both in number of applications and in total volume applied per year per given area. Therefore, the severity and frequency of damage observed on sensitive crops may also increase. Grapes are an important crop in Ohio as fresh fruit and for wine production. The wine industry attracts millions of tourists each year with a measureable positive economic effect. With the predicted increase in use of 2,4-D and dicamba, grape growers are concerned about the potential for damage to their vineyards. This research was conducted to better understand the risk associated with this increased use. Grapes were extremely sensitive to 2,4-D and dicamba, to rates as low as 0.0028 kg ae/ha. A greenhouse study with varieties of grapes likely to be planted in Ohio over the next 10 years indicated that V. vinifera varieties were slightly more sensitive ii than hybrid varieties, showing greater injury symptoms, including leaf cupping (dicamba), chlorosis (glyphosate) and parallel venation, and fan shaped leaves (2,4-D). In a field study, the effects of timing (pre bloom, full bloom, and post bloom) and of rate (0.028, 0.0084, and 0.0028 kg ae/ha) of simulated 2,4-D and glyphosate drift were evaluated on ‘Riesling’ vinifera grape. Fruit yield and quality were measured in 2011 and 2012. In 2011, 2,4-D + glyphosate at 0.0084 kg ae/ha + 0.028 kg ae/ha caused effects on shoot length and visually observable injury symptoms, regardless of application timing. Symptoms of injury included parallel venation, fan shaped leaves, and, in more severely injured vines, death of new shoot growth. However, only 2,4-D + glyphosate at 0.028 kg ae/ha + 0.028 kg ae/ha applied pre and post bloom and 0.0084 kg ae/ha + 0.0084 kg ae/ha applied post bloom affected yield. Post bloom application of 2,4-D + glyphosate at 0.028 kg ae/ha + 0.028 kg ae/ha and 0.0084 kg ae/ha + 0.0084 kg ae/ha also resulted in a loss of yield in the year following the herbicide treatments. One year after application, some vines had died that were treated with post bloom 2,4-D + glyphosate at 0.028 kg ae/ha + 0.028 kg ae/ha and 0.0084 kg ae/ha + 0.0084 kg ae/ha. The application of the pre and full bloom 0.028 kg ae/ha + 0.028 kg ae/ha in 2012 caused much greater injury (96-100% injury) and loss of yield (100%) than in 2011. In conclusion, 2,4-D and dicamba drift may result in severe injury to grapevines; and the rate and timing of the drift can affect the severity of damage observed. The damage caused by the combination of 2,4-D and glyphosate was almost always more severe than either herbicide applied alone in the field. iii Dedication Dedicated to my wife, Danae. iv Acknowledgments I would like to thank the members of the Weed Lab in Wooster who helped with research, ratings, potting, watering, etc., Linjian Jiang, Steven “Vinny” Font, AJ Kropp, Tim Koch, Roger Downer, Jason Parker, Andy Glaser, Erick Mvati, Connie Echaíz, Andrea Sosa, Marlon AC Pangan, Heather McDonough, Ben Morphew, and Ashley Kulhanek. Thanks to The Enology and Viticulture program members including David Scurlock, Todd Steiner, and Patrick Pierquet for providing their vast knowledge on vineyard management and fruit quality. Thank you especially to Greg Johns and his crew at the Ashtabula Agricultural Research Station for managing the vineyard research plot (including pruning, hilling, harvesting assistance, pesticide applications, etc.). Thank you to Mike Davault and Kesia Hartzler and their crew for assisting in greenhouse maintenance and supplies in Wooster. Thank you to Bert Bishop for invaluable SAS lessons and programming assistance. And finally, thank you to Danae (my wife) and to my parents for their advice, help, and support throughout my career. Funding was provided by The Ohio Agricultural Research and Development SEEDS Grant Program, The Ohio Grapes Industries Committee, and Dow AgroSciences. v Vita 2002 Western Reserve Academy (HS) 2006 B.A. Biology, Hiram College 2010 to present Research Assistant, Department of Horticulture and Crop Science, The Ohio State University Peer Reviewed Publications N. Gray, K. Kainec, S. Madar, L. Tomko, and S. Wolfe. “Sink or Swim? Bone Density as a Mechanism for Buoyancy Control in Early Cetaceans,” The Anatomical Record, Volume 290, Issue 6 (June 2007), Pages 638-653. Conference Proceedings S. Wolfe. Response of grapes to simulated 2,4-D, dicamba, and glyphosate drift. 2013 Weed Science Society of America Annual Meeting. S. Wolfe. Response of grapes to simulated 2,4-D, dicamba, and glyphosate drift. 2013 Ohio Grape and Wine Conference Proceedings. Doohan, D., S. Weller, G. Kruger, S. Wolfe, L. Jiang, R. Downer, M. Gardner, R. Johnson, W. Johnson. 2012. 2,4-D and dicamba tolerant crop systems threaten fruit and vegetable production, and agroecosystem services. 6th International Weed Science Congress Proceedings. P. 53. vi S. Wolfe. New Herbicides in 2012 for Grapes in Ohio. 2012 Ohio Grape and Wine Conference Proceedings. S. Wolfe. Response of grapes to simulated 2,4-D, dicamba, and glyphosate drift. 2012 Ohio Grape and Wine Conference Proceedings. S. Wolfe, L. Jiang, D. Scurlock, I. Dami, D. Doohan. 2011. Response of Grapes to Simulated 2,4- D, dicamba, and glyphosate Drift. North Central Weed Science Society 2011 Proceedings. G. Szulgit, N. Abraham, A. Brenneman, J. Collins, M. Crum, K. Davidson, G. Dottle, E. Khalil, S. Latosky, J. Moore, K. Ottey, B. Shelton, K. Wardell, S. Wolfe. “Agents extracted from the body wall of the sea cucumber, Cucumaria frondosa, affect mutability in the tissues of other echinoderms as well,” 12th International Echinoderm Conference, August 2006. Newsletters/Webpages S. Wolfe. DriftWatch: An Overview. Ohio Produce Growers and Marketers Association TODAY. Winter Issue 2012. S. Wolfe. 2011. Introduction to MapMaker and Creating a Linkage Map. eXtension, http://www.extension.org/article/32510 (last confirmed on 1/27/2012). Fields of Study Major Field: Horticulture and Crop Science vii Table of Contents Abstract ............................................................................................................................................ ii Dedication ....................................................................................................................................... iv Acknowledgments............................................................................................................................ v Vita.................................................................................................................................................. vi List of Tables ...................................................................................................................................ix List of Figures ................................................................................................................................. xii Chapter 1: Introduction to Herbicides and Drift .............................................................................. 1 Chapter 2: Response of Five Wine Grape Varieties to 2,4-D, Dicamba, and Glyphosate Simulated Drift ................................................................................................................................................ 21 Chapter 3: Response of ‘Riesling’ Grape to Simulated Drift of 2,4-D and Glyphosate ................ 58 References ...................................................................................................................................... 89 Appendix A: Weather Data for Ashtabula Agricultural Research Station, Kingsville, Ohio ........ 94 viii List of Tables Table 2.1: Herbicide treatments applied to five varieties (‘Riesling,’ ‘Chardonnay,’ ‘Chardonel,’ ‘Vidal blanc,’ and ‘Traminette’) of vinifera and hybrid grapes grown in pots. Combination treatments were applied to ‘Riesling’ only. ................................................................................... 46 Table 2.2: The effect of low doses of 2,4-D, dicamba, or glyphosate on the visual injury of five grape varieties (‘Riesling,’ ‘Chardonnay,’ ‘Chardonel,’ ‘Vidal blanc,’ and ‘Traminette’). LSD, p ≤ 0.05. ............................................................................................................................................ 47 Table