NOVEL HERBICIDES AND APPLICATION METHODS FOR TRANSITION OF OVERSEEDED TURFGRASS

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 0220566
• Project Start Date: Oct 1, 2009
• Project End Date: Sep 30, 2014
• Program Code: [(N/A)]- (N/A)

Recipient Organization
VIRGINIA POLYTECHNIC INSTITUTE
(N/A)
BLACKSBURG,VA 24061

Performing Department
Plant Pathology Physiology & Weed Science

Non Technical Summary
Virginia lies in the climatic transition zone between cool- and warm-season turfgrass growing regions. Either cool- or warm-season turfgrass can be grown in Virginia but neither is completely adapted. Over 38% of Virginia?s golf course hectarage is planted to bermudagrass [Cynodon dactylon (L.) Pers. and hybrids], predominately on fairways (Barnes et al. 2006). Over half of these bermudagrass fairways are overseeded with perennial ryegrass (Lolium perenne L.) to maintain a green playing surface during bermudagrass dormancy . Golf course revenue typically increases when fairways are green compared to when fairways are brown and dormant (Horgan and Yelverton 1998). Virginia's turfgrass industry spends $2.84 billion each year to establish and maintain turf using equipment valued at $5.02 billion (Barnes et al. 2006). Golf courses are the fourth largest sector among twelve sectors of the turfgrass industry identified in a 2004 Virginia survey (Barnes et al. 2006). The value of golf and golf-related tourism is likely much greater. Efforts to improve playing conditions through better turfgrass management would serve to benefit the golf industry and thus the Commonwealth of Virginia. This research will aid turfgrass managers in Virginia and abroad in making decisions to control perennial ryegrass on golf courses and athletic fields. Bermudagrass postdormancy transition in the spring is hampered by overseeded perennial ryegrass. Perennial ryegrass which shades bermudagrass stolons and competes for nutrients and other resources, typically dies with summer heat in southern regions, allowing transition from a two-grass fairway back to a bermudagrass monoculture. However in Virginia, summer temperatures are mild enough for perennial ryegrass to survive all summer. Herbicides are needed to control perennial ryegrass in spring and ensure complete transition back to bermudagrass. Recommendations for cultural methods, application timing, and herbicide selection are needed for this process and will be provided through this research.

Animal Health Component

(N/A)

Research Effort Categories

Basic

(N/A)

Applied

(N/A)

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
213	2130	1140	100%

Knowledge Area
213 - Weeds Affecting Plants;

Subject Of Investigation
2130 - Turf;

Field Of Science
1140 - Weed science;

Keywords

turfgrass

bermudagrass

perennial ryegrass

herbicide

flazasulfuron

trifloxysulfuron

foramsulfuron

pesticide mobility

Goals / Objectives
The long-term goals of this research are to improve methods to transition overseeded bermudagrass on golf fairways or athletic fields. Herbicides are needed to control seeded perennial ryegrass and release bermudagrass while avoiding injury of neighboring grasses. Thus, we would like to investigate new application methods to improve turf aesthetics while overseeded grasses are transitioned and characterize flazasulfuron movement in a turfgrass situation with methods to prevent or remedy turfgrass injury from such movement. The specific experimental objectives of this proposal are: I. Determine how the duration of perennial ryegrass competition influences bermudagrass visual cover, biomass, density, and starch content. II. Evaluate novel application methods to partially control perennial ryegrass and improve bermudagrass density and turfgrass aesthetics during spring transition. III. Develop and implement a bioassay to evaluate drift of flazasulfuron and trifloxysulfuron at various distances so that suitable constraints can be added to the flazasulfuron herbicide label. IV. Conduct experiments to evaluate the distance of influence from flazasulfuron dislodged by foot traffic and deposited on creeping bentgrass putting greens.

Project Methods
Field experiments will be conducted at multiple sites in Virginia over a period of 4 years. In the fifth year of the project, results will be published and extended to Virginia's turfgrass practitioners. Bermudagrass will be overseeded with perennial ryegrass in late September in the year before each study. Herbicide will be applied with a CO2-pressurized backpack sprayer calibrated to deliver 30 gal/acre at 40 psi with XR8004 nozzles or with commercial spray equipment. A randomized complete block design will be used and treatments will be replicated at least three times at each site. Bermudagrass cover, bermudagrass biomass accumulation, and total nonstructural carbohydrates (TNC) will be evaluated in these trials. Visual ratings will include percent bermudagrass cover and turf color. Percent bermudagrass cover will be rated on a scale of 0 to 100%, where 0% is no bermudagrass cover and 100% is complete bermudagrass cover. Turf color will be rated on a 1 to 9 scale, where 1 is poor and 9 is excellent and less than 5 indicates unacceptable turf. Bermudagrass biomass accumulation will be determined by removing a plug from each plot using a standard cup cutter, which is 10 cm in diameter. Above ground tissue will be removed from each plug, washed, and dried at 75 C for 48 hours, then weighed. Total nonstructural carbohydrates will be determined using Hendrix's method of rapid extraction and analysis of nonstructural carbohydrates in plant tissues (Hendrix 1993). Injury to the creeping bentgrass putting green will be evaluated visually, with a Spectrum color analyzer, and via chlorophyll fluorescence measurements. Data will be tested for homogeneity of variance and appropriate repeated measures techniques will be used to control the variance structure in the time series treatments. Data will be subjected to analysis of variance and appropriate means will be separated using Fisher's Protected LSD test at P=0.05 for bermudagrass cover, bermudagrass biomass accumulation, and TNC. Where appropriate, regressions will be used to explain the relationship between perennial ryegrass duration of competition and measured bermudagrass responses.

Progress 10/01/09 to 09/30/14

Outputs
Target Audience: This project was targeted at Virginia's turfgrass managers including Hispanic workers and other underprivileged groups. Efforts to extend results of this research included lectures and seminars, some with Spanish translation and signed for hearing impaired, scientific presentations and national and international venues, magazine and trade publications, and internet web sites. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Although only the project director has worked on this project during the last year, over the entire duration of this project several graduate students have learned importantleadership skills, gained scientific mentoring and experience, and attended scientific and industry conferences that provided networking and public speaking experience. How have the results been disseminated to communities of interest? Efforts to extend results of this research included lectures and seminars, some with Spanish, Korean, andMandarintranslation and signed for hearing impaired, scientific presentations and national and international venues, magazine and trade publications, social media, webinar, and internet web sites. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? The goals of this project have been accomplished and reported prior to this reporting period. From these studies, we have discovered that bermudagrass cultivar plays a major role in determining the duration of perennial ryegrass that negatively impacts bermudagrass health. Various bermudagrass cultivars need approximately 60 to 120 days of competition-free growth to maintain desirable turf. These studies have also proven a novel technique for transitioning overseeded grasses effective but application of this technique will require new technology in equipment or pesticide formulation. Future efforts will be aimed at finding industry partners to continue development of the technology. A portion of this work was instrumental in changing labels for the herbicide flazasulfuron to allow more flexible uses on golf courses by demonstrating that drift and lateral relocation of dislodged herbicide does not travel more than a few meters. In 2013 and 2014, we expanded the audience of this project to include international scientists and turfgrass managers in China and Korea where a budding turfgrass industry is currently growing and in need of technical expertise.

Publications

Progress 10/01/12 to 09/30/13

Outputs
Target Audience: This project was targeted at Virginia's turfgrass managers including Hispanic workers and other underprivileged groups, regional turfgrass associations, and international scientific associations related to turfgrass science. Efforts to extend results of this research included lectures and seminars, some withChinese and Koreantranslation and signed for hearing impaired, scientific presentations and national and international venues, magazine and trade publications, and internet web sites. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Efforts to extend results of this research included lectures and seminars, some with Spanish, Chinese, and Koreantranslation and signed for hearing impaired, scientific presentations and national and international venues, magazine and trade publications, and internet web sites. Information from these studies have reached thousands of turfgrass managers, primarily through state turfgrass conferences and pesticide applicator training seminars. What do you plan to do during the next reporting period to accomplish the goals? This project is essentially complete. Additional journal articles are expected in 2014 prior to the final report.

Impacts
What was accomplished under these goals? Most of the goals of this project have been accomplished and reported prior to this reporting period. From these studies, we have discovered that bermudagrass cultivar plays a major role in determining the duration of perennial ryegrass that negatively impacts bermudagrass health. Various bermudagrass cultivars need approximately 60 to 120 days of competition-free growth to maintain desirable turf. These studies have also proven a novel technique for transitioning overseeded grasses effective but application of this technique will require new technology in equipment or pesticide formulation. Future efforts will be aimed at finding industry partners to continue development of the technology. A portion of this work was instrumental in changing labels for the herbicide flazasulfuron to allow more flexible uses on golf courses by demonstrating that drift and lateral relocation of dislodged herbicide does not travel more than a few meters. In 2013, we expanded the audience of this project to include international scientists in China and Korea where a budding turfgrass industry is currently growing and in need of technical expertise.

Publications

• Type: Journal Articles Status: Published Year Published: 2013 Citation: Askew, S. D., M.J.R. Goddard, W.L.B. Askew, J. B. Beam, and R. J. Keese. 2013. Effect of trifloxysulfuron sodium rate and sequential treatments on transition of overseeded bermudagrass fairways. Int. Turf. Soc. Res. J. 12:689-694.
• Type: Journal Articles Status: Published Year Published: 2013 Citation: Cox, M. C., T. L. Mittlesteadt, and S. D. Askew. 2013. Improving perennial ryegrass overseeding in 'Patriot' bermudagrass using cultural and chemical treatments. Int. Turf. Soc. Res. J. 12:231-236.
• Type: Journal Articles Status: Published Year Published: 2013 Citation: Smith, A. N., J. B. Willis, and S. D. Askew. 2013. Absorption and translocation of flazasulfuron applied to shoots and roots of Lolium perenne L. Int. Turf. Soc. Res. J. 12:685-687.
• Type: Journal Articles Status: Published Year Published: 2013 Citation: Venner, K. A., T. L. Mittlesteadt, and S. D. Askew. 2013. Improving quality of bermudagrass post-dormancy transition using partial control techniques. Int. Turf. Soc. Res. J. 12:707-711.

Progress 10/01/11 to 09/30/12

Outputs
OUTPUTS: Determine how the duration of perennial ryegrass competition influences bermudagrass visual cover, biomass, density, and starch content. Evaluate novel application methods to partially control perennial ryegrass and improve bermudagrass density and turfgrass aesthetics during spring transition. Develop and implement a bioassay to evaluate drift of flazasulfuron and trifloxysulfuron at various distances so that suitable constraints can be added to the flazasulfuron herbicide label. Conduct experiments to evaluate the distance of influence from flazasulfuron dislodged by foot traffic and deposited on creeping bentgrass putting greens. From these studies, we have discovered that bermudagrass cultivar plays a major role in determining the duration of perennial ryegrass that negatively impacts bermudagrass health. Various bermudagrass cultivars need approximately 60 to 120 days of competition-free growth to maintain desirable turf. These studies have also proven a novel technique for transitioning overseeded grasses effective but application of this technique will require new technology in equipment or pesticide formulation. Future efforts will be aimed at finding industry partners to continue development of the technology. PARTICIPANTS: The following individuals worked on this project: Dr. Shawn Askew, Associate Professor, Principal Investigator, and Project Director; John Willis, Matt Goddard, Brent Compton, Tyler Mittlesteadt, Jen Jester, Angela Post, Michael Cox, Adam Smith, Kate Venner, and Brendan McNulty graduate students. Partial funding was provided by the Virginia Turfgrass Council, Virginia Agricultural Council, Golf Course Superintendents Association of America, and Virginia Golf Course Superintendents Association. Drs. Mike Goatley and Erik Ervin of the Crop Soils and Environmental Sciences Department at Virginia Tech collaborated on portions of this research. TARGET AUDIENCES: This project was targeted at Virginia's turfgrass managers including Hispanic workers and other underprivileged groups. Efforts to extend results of this research included lectures and seminars, some with Spanish translation and signed for hearing impaired, scientific presentations and national and international venues, magazine and trade publications, and internet web sites. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
A portion of this work was instrumental in changing labels for the herbicide flazasulfuron to allow more flexible uses on golf courses by demonstrating that drift and lateral relocation of dislodged herbicide does not travel more than a few meters.

Publications

• Smith, A. N., J. B. Willis, and S. D. Askew. 2013. Absorption and translocation of flazasulfuron applied to shoots and roots of Lolium perenne L. Int. Turf. Soc. Res. J. 12:(In Press).
• Cox, M. C., T. L. Mittlesteadt, and S. D. Askew. 2013. Improving perennial ryegrass overseeding in 'Patriot' bermudagrass using cultural and chemical treatments. Int. Turf. Soc. Res. J. 12:(In Press).
• Venner, K. A., T. L. Mittlesteadt, and S. D. Askew. 2013. Improving quality of bermudagrass post-dormancy transition using partial control techniques. Int. Turf. Soc. Res. J. 12:(In Press).
• Askew, S. D., M. J.R. Goddard, W. L.B. Askew, J. B. Beam, and R. J. Keese. 2013. Effect of trifloxysulfuron sodium rate and sequential treatments on transition of overseeded bermudagrass fairways. Int. Turf. Soc. Res. J. 12:(In Press).
• Post, A. R., S. Askew, and D. Spak. 2012. Transitioning overseeded bermudagrass fairways with SP 25052. Proc. South. Weed Sci. Soc. 65:219.

Progress 10/01/10 to 09/30/11

Outputs
OUTPUTS: Several field trials were completed during this reporting period. These and other data related to this project have been presented at national and regional scientific meetings, field days, symposia, workshops, and trainings. Dissemination was provided through handouts and technical bulletins to intended audiences and through publication of research results and presentation materials on the internet. PARTICIPANTS: The following individuals worked on this project: Dr. Shawn Askew, Associate Professor, Principal Investigator, and Project Director; John Willis, Matt Goddard, Brent Compton, Tyler Mittlesteadt, Jen Jester, Angela Post, and Brendan McNulty graduate students. Partial funding was provided by the Virginia Turfgrass Council, Virginia Agricultural Council, Golf Course Superintendents Association of America, and Virginia Golf Course Superintendents Association. Drs. Mike Goatley and Erik Ervin of the Crop Soils and Environmental Sciences Department at Virginia Tech collaborated on portions of this research. TARGET AUDIENCES: This project was targeted at Virginia's turfgrass managers including Hispanic workers and other underprivileged groups. Efforts to extend results of this research included lectures and seminars, some with Spanish translation and signed for hearing impaired, scientific presentations and national and international venues, magazine and trade publications, and internet web sites PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
From these studies, we have learned that flazasulfuron and trifloxysulfuron, two herbicides important to the bermudagrass turf market for transitioning overseeded grasses, pose minimal drift risks at distances beyond 5 meters. Data from field studies conducted at Virginia Tech in Blacksburg were submitted to EPA and a decision was made to reduce buffer zones for flazasulfuron. This herbicide could not have been used in the US turf market if previous buffer zones had remained on the label.

Publications

• Askew, S. D. and A. R. Post. 2011. Movement of sulfonylurea herbicides to nontarget sites. Weed Sci. Soc. Am. Abstracts 51:56.
• McNulty, B.M.S., T. Mittlesteadt, and S. D. Askew. 2011. Duration of perennial ryegrass competition affects bermudagrass quality. Weed Sci. Soc. Am. Abstracts 51:62.
• McNulty, B.M.S., T. Mittlesteadt, and S. D. Askew. 2011. Partial control: a novel approach to spring transition of overseeded bermudagrass. Weed Sci. Soc. Am. Abstracts 51:61.
• Post, A. R., J. L. Jester, S. D. Askew, and M. D. Grove. 2011. Field assessment of flazasulfuron and trifloxysulfuron sodium drift using a corn (Zea mays) bioassay. Proc. South. Weed Sci. Soc. 64:96.

Progress 10/01/09 to 09/30/10

Outputs
OUTPUTS: Several field trials were completed during this reporting period. These and other data related to this project have been presented at four national or international scientific conferences and five regional or local outreach demonstration sites, field days, symposia, workshops, and trainings. Dissemination was provided through handouts and technical bulletins to intended audiences and through publication of research results and presentation materials on the internet. PARTICIPANTS: The following individuals worked on this project: Dr. Shawn Askew, Associate Professor, Principal Investigator, and Project Director; John Willis, Matt Goddard, Brent Compton, Tyler Mittlesteadt, Jen Jester, Angela Post, and Brendan McNulty graduate students. Partial funding was provided by the Virginia Turfgrass Council, Virginia Agricultural Council, Golf Course Superintendents Association of America, and Virginia Golf Course Superintendents Association. Drs. Mike Goatley and Erik Ervin of the Crop Soils and Environmental Sciences Department at Virginia Tech collaborated on portions of this research. TARGET AUDIENCES: This project was targeted at Virginia's turfgrass managers including Hispanic workers and other underprivileged groups. Efforts to extend results of this research included lectures and seminars, some with Spanish translation and signed for hearing impaired, scientific presentations and national and international venues, magazine and trade publications, and internet web sites. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
From these studies, we have learned that bermudagrass requires approximately 100 days of competition-free growth to sustain sufficient biomass and turf quality to meet industry expectations. Starch content on a per unit weight basis is not correlated to the duration of perennial ryegrass competition. Results from this project have lead to revisions of herbicide labels and changes in practices related to the application of transition-assisting herbicides across the country.

Publications

• Askew, S. D. and J. B. Willis*. 2010. Selective bermudagrass control in cool-season turfgrass. Weed Sci. Soc. Am. Abstracts. 50:72.
• Askew, S. D. and M. J. Goddard*. 2010. Directed herbicide application on golf putting greens for annual bluegrass control. Weed Sci. Soc. Am. Abstracts. 50:70.
• Askew, S. D. and M. J. Goddard*. 2010. Selective grass weed control in turf with metamifop. Proc. Northeast. Weed Sci. Soc. 64:72.
• Askew, S. D. and T. R. Murphy. 2009. Relative mobility of transition-assisting herbicides. Int. Turf. Soc. Res. J. 11:1153-1158. Askew, S. D., J. L. Jester*, L. Norton, and D. Spak. 2010. Application timing affects annual bluegrass control with indaziflam. Proc. South Weed Sci. Soc. 63:55.
• Goddard, M.J.R., J. B. Willis, and S. D. Askew. 2009. Application placement and relative humidity affects smooth crabgrass and tall fescue response to mesotrione. Weed Sci. 58:67-72.
• Goddard, M.J.R., S. D. Askew, B. J. Brecke, J. F. Derr, and T. R. Murphy. 2009. Poa annua population response to overseeded perennial ryegrass seeding rate and bispyribac sodium. Int. Turf. Soc. Res. J. 11:1183-1189.
• McNulty*, B., and S. D. Askew. 2010. Aeroponics as a means to elucidate herbicide effects on turfgrass root regeneration. Proc. South Weed Sci. Soc. 63:62.
• Mittlesteadt, T. L., J. M. Goatley, S. D. Askew, K. L. Hensler, and W. L. Askew. 2009. Low-impact conversion of cool-season turf to 'Patriot' bermudagrass. Int. Turf. Soc. Res. J. 11:1205-1212.
• Post*, A. R., J. L. Jester*, S. D. Askew, L. Norton, and D. Spak. 2010. Turfgrass response to indaziflam. Proc. South Weed Sci. Soc. 63:56.