Progress 07/01/04 to 06/30/09
Outputs
OUTPUTS: During this project, research was conducted on spring dead spot of bermudagrass, diseases of seashore paspalum in SC, development of fungicide-based disease control programs for bent and bermudagrass putting greens, and on the biology and control of rapid blight of cool season grasses, caused by Labyrinthula terrestris. A post-doctoral scientist, Dr. Paul Peterson, worked with rapid blight as a team member, and a graduate student, Mr. Alejandro Canegallo, completed his M.S. work on cultivar performance and diseases in seashore paspalum, a new turfgrass for South Carolina. Seminars were conducted through cooperation with the Golf Course Superintendents of America, the Carolinas Golf Course Superintendents Association, and by sponsoring companies such as Syngenta, Bayer and BASF. Field days were conducted at the Pee Dee Research and Education Center in Florence, SC or on the main Clemson campus annually, where data and conclusions were disseminated to clientele. Numerous phone calls, email communications and articles were prepared with results, conclusion and recommendations to improve disease management on putting greens in South Carolina. PARTICIPANTS: Dr. Jim Camberato, Professor, Purdue University was a partner in the work with rapid blight. Dr. Paul Peterson, post doctoral fellow, was a partner in the work with rapid blight. Alejandro Canegallo was a graduate student that worked on seashore paspalum. Eric Luc was a grad student (did not matriculate) that worked in part on spring dead spot. Many companies provided in kind support of products which aided in construction and maintenance of the research putting greens used in components of the project: Bayer, BASF, Syngenta, Valent were the primary contributors. Partner organizations for dissemination of research results were the Carolinas Golf Course Superintendents Association and the Golf Cours Superintendents Association of America. These organizations provided the venue for in-depth seminars which trained numerous superintendents about disease control in putting greens and provide them with new information in this regard. TARGET AUDIENCES: Target audiences were industry research and sales representatives which sell to the golf course market and also provide information generated through this and similar projects. Target audiences primarily were golf course superintendents who are responsible for providing high quality putting surfaces throughout the growing seasons which can be environmentally challenging. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
During this project we determined that the main causal agent of spring dead spot in bermudagrass putting greens is Ophiosphaerella korrae. It is best controlled with fenarimol (Rubigan) fungicide, followed by propiconazole (Banner). Strobilurin fungicides have reduced efficacy although Heritage is labeled. Best control was achieved with 12 oz of Rubigan applied as 3 applications of 4 oz or 2 applications of 6 oz or with tank-mix or alternations of Rubigan and thiophanate methyl fungicide. Recommendations based on this work have greatly reduced spring dead spot occurrence on putting greens in the southeastern United States. Rapid blight, caused by Labyrinthula terrestris, continued to be a problematic disease on overseeded golf putting greens with salinity problems. Data on host range showed that Poa annua and Poa trivialis cultivars are highly susceptible, and that perennial ryegrass cultivars vary greatly in susceptibility. Slender creeping red fescue is highly tolerant, with moderate tolerance in alkaligrass. These data provided good information on relative risk with different grasses. The fungicides pyraclostrobin, trifloxystrobin and mancozeb were found to be efficacious for control of rapid blight, with numerous other fungicides not showing efficacy. Water composition was shown to vary in salinity and ionic components contributing to salinity. Sodium concentration was shown to be the primary determinant in water related to rapid blight development and to be positively correlated with disease severity. So, fungicides, species of grass and cultivar, and salinity manipulation have provided the integrated control components for rapid blight disease. Disease control programs in bentgrass and bermudagrass were tested and refined during this project. Strategies employed use of DMI fungicides preventively in the beginning of summer and end of summer but avoided their use in mid-summer. Tank-mixes of DMI's with chlorothalonil reduced the problems and improved disease control. Strobilurin fungicides were tested in programs, and Insignia in particular was shown to be highly effective for summer stress prevention and disease control when deployed in June and July. Other components relied on chlorothalonil for algae control, resistance management, and disease control in tank-mixes. A pigment added to Bayer products labeled as 'StressGuard' was shown to improve disease control and stress reduction in bentgrass and bermudagrass. These factors are used as basic information to design programs whereby the fungicides are deployed in a strategy to result in superior disease control. Programs designed for bentgrass have been used successfully throughout the southeastern United States. Seashore paspalum generates interest in the southeast as a species for putting greens. It is very salt-tolerant once it is established and has very desirable aesthetic qualities. Seven cultivars were evaluated for quality and disease susceptibility. Two cultivars performed well at 2 locations: SeaDwarf and SeaIsle Suprememe. All cultivars were susceptible to large patch (Rhizoctonia solani AG 2-2 'LP') which was reported on paspalum through this research.
Publications
- No publications reported this period
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: Outputs have been disseminated by website (www.clemson.edu/turfornamental) and by personal seminars to stakeholders within South Carolina through the Carolinas Golf Course Superintendents Association annual conference and through regional seminars within SC. In the past year these have been presented in Charleston, Greenville, and Hilton Head. Outside of SC, results of research and impacts have been communicated through seminars sponsored by the Golf Course Superintendents Association of America. These were presented in Orlando. Regional seminars were presented in various states throughout the southestern United States, including Florida, Alabama, North Carolina and Georgia. PARTICIPANTS: Participants have included the Golf Course Superintendents Association of America, and the Carolinas Golf Course Superintendents, who organized and provide venues for presentation of research results from this project. TARGET AUDIENCES: Target audience is primarily golf course superintendents in South Carolina and secondarily in the southeast region of the United States. Results and programs developed from this project are relevant to these and related groups. Ultimately the beneficiary of the research are the businesses that rely on tourism income as well as private social and recreation organizations. This group has been encouraged to adopt the research results through seminars and field days where results are reported or demonstrated. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
We gained greater understanding of the cause of Rhizoctonia leaf and sheath spot (R. zeae and related fungi) in bermudagrass putting greens. This disease is increasing in frequency of occurrence and specific control recommendations were developed as a result of this project. These include the identification of causal organisms and their control with fungicides such as azoxystobin, propiconizole and others. Post application irrigation of these fungicides was shown to be important and was communicated to stakeholders. In the past 2 years a modified disease control program for bentgrass diseases in the southeast was developed and has shown consistent high quality results and has been adopted by many superintendents throughout the southeast. The USGA regional agronomists have assisted in promoting the efficacy of the program throughout the region.
Publications
- No publications reported this period
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: Fungicides were evaluated for control of Spring Dead Spot (SDS) on golf putting greens. The greens were planted with TifEagle and MiniVerde bermudagrass cultivars. Both cultivars appear to be very susceptible to SDS. Fungicide trials to determine relative efficacy of labeled fungicides have continued to show fenarimol to be most effective, and a granular formulation developed by Gowan Company has proved to be highly efficacious. Sequential applications of fenarimol followed by thiophanate methyl have provided good but not excellent control but may be an option for managers seeking less non-target growth regulation effects from fenarimol alone. Azoxystrobin , although labeled for SDS is not effective, nor is pyraclostrobin according to trial results. Fungicide programs for disease control and turf quality have continued to be evaluated and shown to be variable in effectiveness depending on how and when fungicides are deployed through heat stress summer months. Generally
fungicides that improve stress tolerance and provide good disease control, such as pyraclostrobin or tank-mix combinations of fosetyl Al (Chipco Signature) with chlorothalonil (Daconil) have provided excellent results when deployed in the most stressful months (July and early August in SC).
PARTICIPANTS: Amy V. Turner and Albert Lynn are part-time technicians supervised by the principal investigator Samuel Bruce Martin, Jr. Summer assistance by Laurie Gregg (high school student). Plot maintenance by Ryan Graham. Partner organizations have included Syngenta, Bayer CropScience, Valent, BASF, Gowan company, Helena, and others. Data from this research is used in continuing education trainings coordinated by Clemson, the Carolinas Golf Course Superintendents Association and the Golf Course Superintendents Association of America (GCSAA). Actual research is presented during turfgrass field days held annually at Clemson campus and at the Pee Dee Research and Education Center.
Impacts
Turfgrass managers throughout the southeast have excellent recommendations for control of spring dead spot on new bermudagrass putting greens. Turfgrass managers have been shown guidelines for strategic deployment of fungicides for management of major turf diseases and maintenance of excellent quality on bentgrass putting greens through stressful summer months.
Publications
- Peterson, P.D., S. B. Martin, and J. J. Camberato. 2007. Current understanding and management of rapid blight disease on turfgrasses. In: Handbook of Turfgrass Management and Physiology. M. Pessarakli, ed. CRC Press, Boca Raton, FL
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Progress 01/01/06 to 12/31/06
Outputs
Large patch in seashore paspalum, caused by Rhizoctonia solani AG 2-2 LP was documented and Koch's postulates completed in 2005-2006. The disease is potentially a major limiting factor for successful culture of this grass for commercial turf purposes in transition zone environments. Curative control with fungicides was only partially effective, with pyraclostrobin and azoxystrobin providing the best control. Rapid blight continues to be a threat for cool season grasses in salt-affected sites. Increasing salinity increases rapid blight, with the magnitude of disease and salinity induced necrosis increasing greater in susceptible hosts vs. salt-tolerant hosts. Sodium concentration has been implicated as important for rapid blight occurrence and grasses affected by rapid blight accumulate sodium in leaves to the detriment of potassium. Little genetic diversity has been found to date in isolates of Labyrinthula terrestris, the causal agent of rapid blight disease. Spring
dead spot in ultradwarf bermudagrass greens was documented again in 2006, with the causal agent Ophiosphaerella korrae associated with the disease. Effective fungicides include fenarimol, especially a granular formulation.
Impacts
Rapid blight continues to be a threat in salt-affected sites. Increasing salinity increases necrosis due to salts and rapid blight, and infected leaves had increased levels of sodium and decreased potassium concentrations. Large patch is a major threat to the successful culture of seashore paspalum in SC.
Publications
- Camberato, J. J., Peterson, P.D., and Martin, S. B. 2006. Salinity and salinity tolerance alter rapid blight in Kentucky bluegrass, perennial ryegrass and slender creeping red fescue. Online. Applied Turfgrass Science doi:10.1094/ATS-2006-0213-01-RS
- J. J. Camberato, P.D. Peterson, and S. B. Martin. 2006. Irrigation water composition affects rapid blight of cool-season turfgrasses. Phytopathology 96:S18.
- Camberato, J. J., P.D. Peterson, and S.B. Martin. 2006. Irrigation water composition alters plant mineral composition and rapid blight on perennial ryegrass. In Agronomy abstracts, ASA,SSSA,CSA, Madison, WI. http://a-c-s.confex.com/crops/2006am/techprogram/P24368.HTM
- Canegallo, A., Martin, B., Camberato, J. and Jeffers, S. 2006. Occurrence and Control of Large Patch (Rhizoctonia solani AG 2-2 LP) in Seashore Paspalum (Paspalum vaginatum Swartz) in South Carolina . Phytopathology 96: S19.
- Craven, K.D., Peterson, P.D., Mitchell, T.K., and Martin, S.B. 2006. Genetic divesity among Labyrinthula terrestris isolates, the causal agent of rapid blight disease on turfgrass. Phytopathology 96:S27.
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Progress 01/01/05 to 12/31/05
Outputs
Spring dead spot (SDS) of bermudagrass was identified on putting greens of TifDwarf and TifEagle cultivars. PCR primers were used to identify suspected causal agents isolated from diseased roots. Ophiosphaerella korrae was identified as the sole causal agent from several golf courses. In fall of 2004, a research putting green planted to TifEagle and MiniVerde bermudagrass cultivars was inoculated with O. korrae. SDS was reproduced in inoculation sites and O. korrae re-isolated. Both cultivars appear to be very susceptible to SDS. Fungicide trials to determine relative efficacy of labeled fungicides have continued to show fenarimol to be most effective, followed by propiconazole. Variable effectiveness was found with myclobutanil, azoxystrobin or thiophanate methyl, among fungicides labeled for SDS. The effects of salinity and cultivar were tested in ryegrasses,bluegrasses or creeping red fescues with or without rapid blight, caused by Labyrinthula terrestris. Necrosis
due to rapid blight increased as salinity increased from 0.13 to 5.0 dS/M. Effects of salinity and salinity due to rapid blight were dependent on species of turfgrass, with species susceptible to salinity (e.g. ryegrasses) being more damaged by salinity and rapid blight than more salinity-tolerant grasses (e.g. creeping red fescues).
Impacts
Programmatic approaches for bentgrass diseases have been adopted and similar programs are being adopted for ultradwarf bermudagrass greens. Both in bentgrass and bermudagrass, disease control and turf quality have been substantially improved. Spring dead spot has continued to be a threat to bermudagrass putting greens in Transition Zone environments, and our research has shown fenarimol and propiconazole to most efficacious. In South Carolina, the sole causal agent for SDS was identified as Ophiosphaerella korrae. Rapid blight continues to be a threat in salt-affected sites. Our recent research showed that species of turf susceptible to salinity are damaged more when rapid blight is present. Even salt-tolerant grasses are damaged more by rapid blight when exposed to high salinity, but the level of damage is correlated with salinity tolerance.
Publications
- Camberato, J.J., Peterson, P.D., and Martin, S.B. 2005. Salinity and what it means to turf after rapid blight. Carolinas Green March-April, pp. 19-21.
- Camberato, J.J., Peterson, P.D., and Martin, S.B. 2005. Salinity and salinity tolerance alter rapid blight disease occurrence. Phytopathology 95: S83.
- Craven, K.D., Peterson, P.D., Martin, S.B., and Mitchell. 2005. Genetic diversity among rapid blight pathogens of cool-season turfgrass. Inoculum 56:14.
- Craven, K.D., Peterson, P.D. Windham, D.E., Mitchell, T.K., and Martin, S.B. 2005. Molecular identification of the turfgrass rapid blight pathogen. Mycologia 97:160-166.
- Peterson, P.D., Martin, S.B., and Camberato, J.J. 2005. Tolerance of cool-season turfgrasses to rapid blight disease. Applied Turfgrass Science doi:10.1094/ATS-2005-0328-01-RS.
- Peterson, P.D., Martin, S.B., Camberato, J.J., and Fraser, D.E. 2005. The effect of temperature and salinity on growth of the turfgrass pathogen, Labyrinthula terrestris. Phytopathology 95:S83.
- Stowell, L.J., S.B. Martin, M. Olsen, D. Bigelow, M. Kohout, P.D. Peterson, J.J. Camberato, W.D. Gelernter. 2005. Rapid Blight: A New Plant Disease. APSnet Feature Story, July. http://apsnet.org/online/feature/rapid/
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Progress 01/01/04 to 12/31/04
Outputs
Replicated trials were conducted to evaluate fungicides in programmatic approaches for summer disease control in bentgrass greens. Programs that provided excellent brown patch control in mid-summer and excellent dollar spot control throughout the summer, while avoiding growth regulation with DMI fungicides, were best. Spring dead spot of bermudagrass was identified on putting greens of TifDwarf and TifEagle cultivars. PCR primers were used to identify suspected causal agents isolated from diseased roots. Ophiosphaerella korrae was identified as the primary causal agent from several golf courses. Fungicide trials to determine relative efficacy of labeled fungicides have shown fenarimol to be most effective, followed by myclobutanil. Isolates of Labyrinthula from sites affected by rapid blight were obtained from SC, NC, CA, AZ, and NV. A study of the phylogenetic relationship of rapid blight Labyrinthula showed this organism to be unique from described species. Host
range studies of cool season turfgrasses showed alkaligrass, slender creeping red fescues, and creeping bentgrasses to be most tolerant of rapid blight. Susceptible grasses included rough bluegrass, perennial ryegrasses, and annual bluegrass among turf-type cool season grasses. Kentucky bluegrasses were intermediate in tolerance to rapid blight.
Impacts
The evaluation of programmatic approaches for control of bentgrass diseases has been adopted and adapted by other investigators as well as companies seeking to optimize the use of products for disease control. Programs developed and evaluated for disease control in South Carolina have been adopted by many golf course superintendents, and have improved summer disease control substantially. Rapid blight, a new disease of certain cool season grasses, was identified in South Carolina. Preliminary data obtained through this project identified fungicides that were effective for control as well as tolerant grasses that might be used for overseeding of bermudagrass putting greens in rapid blight-prone sites. Causal agents have been identified for spring dead spot on new ultradwarf bermudagrass putting greens in SC. This is important to begin to develop better disease management systems such as improved fungicide efficacy and deployment. Fungicide efficacy trials have shown
rubigan to be most efficacious among labeled fungicides for SDS on putting greens.
Publications
- Paul Peterson, Bruce Martin, and Jim Camberato. 2004. Rapid blight diseae of cool-season grasses. USGA SGreen Section Record 42, number 5:20-24.
- Paul Peterson, Bruce Martin, and Jim Camberato. 2004. Rapid blight disease of cool season grasses. Turf Environmental Research Online. April 2004.
- Martin, Bruce and Jim Camberato. 2004. Early data in on ultradwarf response to high sand content. Carolinas Green, Jan-Feb.
- P.D. Peterson, S. B. Martin and J. J. Camberato. 2004.Determining the host range of Labyrinthula sp., the causal agent of rapid blight. Phytopathology 94:S83.
- S. R. Parker, S. B. Martin, J. J. Camberato, and S. N. Jeffers. 2004.Effects of spring-applied fungicide applications on disease and quality of rough bluegrass overseeded bermudagrass putting greens. Phytopathology 94.s81.
- S. B. Martin, M.W. Olsen, P.D. Peterson, and J. J. Camberato. 2004.Evaluation of fungicides for control of rapid blight on cool season turfgrasses. Phytopathology 94. S66.
- K. D. Craven, P.D. Peterson, T. K. Mitchell, and S. B. Martin. 2004.Phylogenetic relationships between the rapid blight pathogen of turf and aquatic protists in the genus Labyrinthula. Phytopathology 94. S22.
- S. R. Parker, S. B. Martin, S. N. Jeffers, and J. J. Camberato. 2004. Identification and pathogenicity of Pythium spp. associated with roots of hybrid bermudagrass in overseeded golf course putting greens. Phytopathology 94.s81.
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