Progress 10/01/10 to 09/30/15
Outputs
Target Audience:golf course superintendents, lawn care operators, sod producers, parks and recreational turfgrass management personnel, university faculty and graduate students. 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?Reported at golf course workshops, field days, turfgrass conference meetings. A MSc thesis and manuscripts are in preparation for future publications. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Twenty-nine ERI fungal isolates representing eight morphologically distinct groups were selected from 644 total isolates recovered from UDB roots. The ERI fungi did not reproduce in pure culture nor on host tissues making identification a challenge. Therefore a phylogenetic analysis based on current phylogenetics of Magnaporthaceae was designed for identification purposes. Six partial conserved genes of the undescribed ERI fungi were amplified and sequenced: internal transcribed spacer [ITS] region of ribosomal RNA, 28S large subunit [LSU] rRNA, 18S small subunit [SSU] rRNA, DNA replication licensing factor gene [MCM7], largest subunit of RNA polymerase II gene [RBPI], and translation elongation factor 1-alpha gene [TEF1]. Magnaporthiopsis poae and G. graminis graminis, ERI pathogens of turfgrass roots were also included in the analysis. Phylogenetic trees of the individual and composite genes were estimated by Bayesian inference and maximum likelihood in MEGA6. Five novel species within Magnaporthiopsis and Gaeumannomyces, a novel species within a newly described genus, Pseudophialophora, and a novel genus/species, Candidacolonium cynodontis, were identified based on the multi-locus phylogenetic analysis. The optimal temperature for growth and infection of the novel ERI fungi ranged from 26 to 29 oC which is similar to those of UDB during the summer months in the South. Whole plant inoculations of two UDB cultivars using each species alone and in a fungal composite were conducted in growth chamber studies. Following eight weeks, roots were evaluated for disease. WhinRhizo scan and software system was used to determine total root length and color analysis for root rot. Shoot and root dry weights, stem growth, and nodes producing roots were determined and analyses are currently underway. The pathogenicity evaluation results indicated all novel ERI fungi were pathogenic to UDB roots as each novel species was successfully recovered from infected roots and identified as the fungus of origin thus satisfying Koch's postulates. Within the group several novel ERI fungi were highly virulent causing black rotted roots and stolons or completely inhibiting root production. The novel ERI fungi, Candidacolonium cynodontis and G. paulograminis caused significant damage to stolons, crowns, and roots of UDB compared to G. graminis graminis, the bermudagrass decline pathogen. M. paulograminis was the predominant ERI fungus isolated from roots in the fungal composite treatment. M. incrustans, commonly associated with UDB roots but not considered a pathogen, did not cause significant root disease in this study.
Publications
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2015
Citation:
Vines, P,. Tomaso-Peterson, M., Allen, T. Evaluating novel ectotrophic root-infecting fungi as possible etiological agents for summer decline of ultradwarf bermudagrass. Southern Division-American Phytopathological Society. Phytopathology 105:S2.11.
- Type:
Theses/Dissertations
Status:
Accepted
Year Published:
2015
Citation:
Evaluation of ultradwarf bermudagrass cultural management practices and identification, characterization, and pathogenicity of ectotrophic root-infecting fungi associated with summer decline of ultradwarf bermudagrass putting greens.
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Progress 10/01/13 to 09/30/14
Outputs
Target Audience: golf course superintendents, lawn care operators, sod producers, parks and recreational turfgrass management personnel, university faculty and graduate students. 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? Reported at golf course workshops, field days, turfgrass conference meetings. What do you plan to do during the next reporting period to accomplish the goals? Publish results.
Impacts
What was accomplished under these goals?
Major activities completed: Second season (June – November 2013) of field research has been completed. Data analysis for most parameters is complete and includes turfgrass quality, normalized difference vegetative index (NDVI), firmness, ball roll (stimpmeter), and root data. The data will be discussed in terms of plant health and playability; how the putting green surface affects characteristics that are desirable to the golfer. Data analysis is complete for NDVI, turfgrass quality, surface firmness, and ball roll for both years. Significant results: Turfgrass health: The normal difference vegetative index (NDVI) measures reflected light in the red (660 nm) and near infrared (850 nm) spectral bands and is recorded with a reflectance value of 0.0 to 1.0. NDVI is used as an indicator of turfgrass color with dark green (1.0) as desirable. When considering the main effects of the study, the seasonal fungicide program significantly improved NDVI across all cultivation practices as well as UDB cultivars in both years, indicating improved turfgrass color and overall health through the control of foliar diseases. The once-per-month slice, spike, or scarify practices produced significantly greater NDVI values that other cultivation practices throughout the early growing season; however, by mid-July all cultivation practices improved NDVI values compared to the weekly vertical mow. A weekly vertical mow is considered an aggressive practice as turfgrass plants do not have a sufficient recovery period specifically at the beginning and end of the growing season. Both UDB cultivars differed in NDVI at the mid-July and mid-October rating dates, but for most of the growing season both cultivars had similar NDVI. In 2013, cultivation practices had similar NDVI values until late August when the vertical mow practice showed a reduction in NDVI valued through mid-October. The response in NDVI became significant among cultivation practices in the early stages of this study. Both cultivars responded to cultivation practices after lack of management for three years. In the second year, both cultivars responded similarly and cultivation practices did not have an immediate impact on NDVI until the latter part of the growing season. The assessment of turfgrass quality, comprised of density, color, uniformity, and texture, was visually rated on a scale of 1 to 9 where 9 = best and 6 = acceptable turfgrass quality. The weekly vertical mow treatment negatively impacted turfgrass quality in Champion UDB in 2012 and the weekly vertical mow with scarify, spike, or slice substituted also negatively impacted turfgrass quality those dates cultivation practices were significant. These four cultivation practices are aggressive indicating Champion UDB is not fully recovering in terms of turfgrass quality. The once-per-month cultivation practices were less injurious to Champion and this was reflected in greater turfgrass quality. Miniverde UDB displayed acceptable turfgrass quality when aggressive cultivation practices were applied during the 2012 growing season. However, toward the end of the growing season when the plants are transitioning into dormancy, turfgrass quality was reduced in the weekly vertical mow plots (Table 3). Based on our observations, MiniVerde UDB responded favorably to aggressive cultivation practices compared to Champion UDB in 2012. A similar trend was observed in 2013 when Champion UDB was cultivated with the aggressive, weekly practices. Turfgrass quality was sacrificed under those aggressive practices for all dates where cultivation practice was significant. Overall, the turfgrass quality of Champion was not acceptable at most rating dates for any cultivation practice throughout the 2013 growing season. The overall turfgrass quality of Miniverde was also marginal in 2013. In contrast to 2012, Miniverde turfgrass quality was reduced under the aggressive, weekly applications of vertical mow or a substituted slice, spike, or scarify. Although turfgrass quality was improved in the once-per-month cultivation practices, the majority of the growing season turfgrass quality was less than acceptable. The seasonal fungicide application improved turfgrass quality regardless of cultivar, cultivation practice, or year. Dollar spot is a foliar disease which causes significant foliar blight in the spring and fall months. A dollar spot epidemic occurred in this study the fall of 2012 which carried over into the spring of 2013 causing a significant reduction in turfgrass quality in both UDB. The growing season (spring green-up) of 2013 was delayed into June with the preceding months experiencing temperatures below normal. Delayed growth may have had an impact on turfgrass quality for both UDB cultivars. We did not observe vigorous growth until the latter part of July into August as reflected by acceptable turfgrass quality ratings in Champion and Miniverde UDB, August 2013. In summary, NDVI and turfgrass quality were improved when less aggressive cultural practices were applied in conjunction with a seasonal fungicide program. Playability: Golf ball roll distance is a practice used by United States Golf Association (USGA) to determine smoothness of a putting green surface. The USGA uses a stimpmeter that measures 2.5 ft from the top portion of the ball notch. We fabricated a modified stimpmeter for use on small research plots as used in this study. The modified stimpmeter measured 0.62 ft from the top portion of the ball notch. An identical 20-degree angle was fabricated on the terminal end of the modified stimpmeter to ensure the ball approaches the surface of the green at the desired speed. Stimpmeter readings (distance in feet the golf ball rolls on the putting green surface) were recorded on a monthly basis during the time period from June through October. There were no pertinent conclusions to be made regarding green speed, other than an increase in ball roll distance when no fungicide was applied. This is likely due to reduced foliar material present on these plots; therefore, recommending that fungicide applications not be made to increase green speed would not be warranted. Additionally, no true difference between the two cultivars was observed; however, at various times throughout the two years, Champion UDB did exhibit significantly greater ball roll distances than Miniverde. Surface firmness levels were assessed with the TruFirm device from the USGA and recorded once each month from June to November in 2012 and 2013. In consideration of the three-factor interaction (Year x Practice x Time), applications of vertical mowings on a weekly basis were consistently superior with respect to surface firmness; however, incorporations of less aggressive practices provided comparable results. Furthermore, it was observed that applying less aggressive practices once each month resulted in significantly softer surfaces throughout the two years of the study. When the three-factor interaction (Cultivar x Fungicide x Practice) is considered, it can be concluded that, within each cultivar, there is no appreciable difference between no fungicide and fungicide with respect to surface firmness. When a fungicide was present on champion, weekly applications of vertical mow or vertical mow with once monthly slice or scarify yielded the best surface firmness responses. When a fungicide was present on MiniVerde, weekly applications of vertical mow, vertical with once monthly slice, spike, or scarify, or the once monthly scarify treatment provided the best results with respect to surface firmness.
Publications
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2014
Citation:
Vines, P. L., Tomaso-Peterson, M., Allen, T. W., Hoffmann, F. Multilocus analysis reveals phylogenetic placement of novel ERI fungi within Magnaporthaceae of Ascomycota. American Phytopathological Society annual meeting. Minneapolis, MN. August 12, 2014.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2013
Citation:
Characterizing the ectotrophic root-infecting fungal populations responsible for declining ultradwarf bermudagrass putting greens. P.L. Vines, M. Tomaso-Peterson, T.W. Allen, B.R. Stewart, F. Meyer, and J. Dubien. CSSA [2013]. p. 822250.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2013
Citation:
An evolutionary assessment of ectotrophic root-infecting fungi isolated
from ultradwarf bermudagrass roots. P. L. VINES, M. Tomaso-Peterson, T. W. Allen, F. Meyer, F. Hoffmann. Mississippi State University, Mississippi State, MS, U.S.A. 2014. Phytopathology 104(Suppl. 2):S2.11.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2014
Citation:
Vines, P. L., Tomaso-Peterson, M., Allen, T. W., Balbalian, C., Stewart, B. R. Distribution of ectotrophic root-infecting fungi associated with declining ultradwarf bermudagrass putting greens. American Phytopathological Society annual meeting. Minneapolis, MN. August 11, 2014.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2013
Citation:
A Molecular and biological examination of ectotrophic root-infecting fungi isolated from roots of ultradwarf bermudagrass putting greens. P.L. Vines, M. Tomaso-Peterson, T.W. Allen, B.R. Stewart, F. Meyer, and J. Dubien. Mississippi Association of Plant Pathologists and Nematologists. MSU 22 October 2013.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2013
Citation:
Characterizing the ectotrophic root-infecting fungal populations responsible for declining ultradwarf bermudagrass putting greens. P.L. Vines, M. Tomaso-Peterson, T.W. Allen, B.R. Stewart, F. Meyer, and J. Dubien. Crop Science Society of America. Tampa, FL. 4 November 2013.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2014
Citation:
An evolutionary assessment of ectotrophic root-infecting fungi isolated from ultradwarf bermudagrass roots. P. Vines, M. Tomaso-Peterson, T. Allen, F. Meyer, and F. Hoffman. Southern Division-American Phytopathological Society meeting, Dallas, TX. 3 February 2014.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2014
Citation:
Vines, P. L. and Tomaso-Peterson, M. May 6, 2014. A review of research conducted on ERI fungi in ultradwarf bermudagrass putting greens and- Pythium diseases of ultradwarf bermudagrass and creeping bentgrass. Alabama Golf Course Superintendents Association Meeting. Tuscaloosa, AL.
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Progress 01/01/13 to 09/30/13
Outputs
Target Audience: Golf course superintendents, athletic field managers, home owners, lawn care operators, sod producers, industry representatives, scientific researchers 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? Golf course superintendents are the target audience for this research as well as plant pathologists. The best management approach using cultural practices and the discovery of ERI pathogens have been presented at golf course superintendent chapter meetings as well as workshops. The impact of characterizing novel ERI fungi associated with UDB roots was presented at American Phytopathological Society meeting in August and was very well-received as this area of turfgrass pathology poses a "black hole" as far asunderstanding this pathosystem.Turfgrass pathologists as well as plant diagnosticians observed these fungi on failing UDB roots but no clear understainding of this relationship was ever defined. What do you plan to do during the next reporting period to accomplish the goals? The final months of data concerning best management practice utilizing cultural practices will be analyzed, interpreted, and results will be presented in a Master's thesis as well as peer-reveiwed publications. The characterization of ERI fungi associated with declining UDB roots will continue with pathogenicity studies, temperature optima, as well as six-gene phylogenetic studies to confirm identify of the representative 139 novel fungi. This information will also be included in a Master's thesis and prepared for peer-reviewed journals within mycology and plant pathology.
Impacts
What was accomplished under these goals?
A final year of data collection on best management practices for healthy ultradwarf bermudagrass (UDB) putting greens is underway. Vertical mowing (7-d) is an aggressive approach for thatch management in UDB. Resulting from this aggressive cultural management practice, turfgrass quality and health are compromised, specifically if a seasonal fungicide program is not employed. Less frequent vertical mow alternated with slicing, spiking, or scarifying results in less turf damage, improved turfgrass quality, acceptable firmness of the putting surface, and reduced disease incidence. Root developement and health appeared to decline as the season progressed with at least a 25% reduction in total linear rooting (cm). This will be an area of importance as we have tracked UDB root development on a bimonthly basis for 18 months and plan to complete a 24-month root survey. The role ectotrophic root-infecting (ERI) fungi play in UDB health has been investigated. It was discovered that many of the ERI fungi associated with declining roots have never been identified. A significant effort has been placed on characterizing the unknown or novel fungi. Over 600 fungal isolates were recovered from UDB roots and a total of 139 were selected for characterization purposes. Preliminary phylogenetic results indicate six new fungal species are included in the collection of ERI fungi. Pathogenicity results indicate there may be host resistance (Champion and Miniverde cultivars are being compared) as well as fungal virulence involved in the root disease.
Publications
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2013
Citation:
Identification of ectotrophic root-infecting fungi in association with ultradwarf bermudagrass. P.L. Vines, M. Tomaso-Peterson, B.R. Stewart, T.W. Allen, and F. Meyer. Southern Division American Phytopathological Society. Baton Rouge, LA. 8 February 2013.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2013
Citation:
Characterization of ectotrophic root-infecting fungi isolated from
ultradwarf bermudagrass (Cynodon dactylon�C. transvaalensis) root
materials. P. L. VINES, M. Tomaso-Peterson, T. Allen, B. Stewart, F.Meyer, J. Dubien. American Phytopathological Society Annual Meeting. 10-14 August 2013.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2013
Citation:
A Molecular and biological examination of ectotrophic root-infecting fungi isolated from roots of ultradwarf bermudagrass putting greens. P.L. Vines, M. Tomaso-Peterson, T.W. Allen, B.R. Stewart, F. Meyer, and J. Dubien. Mississippi Association of Plant Pathologists and Nematologists. MSU 22 October 2013.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2013
Citation:
Characterizing the ectotrophic root-infecting fungal populations responsible for declining ultradwarf bermudagrass putting greens. P. Vines, M. Tomaso-Peterson, B. Stewart, T. Allen, F. Meyer, and J. Dubien. Crop Science Society of America. Tampa, FL. 4 November 2013.
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Progress 01/01/12 to 12/31/12
Outputs
OUTPUTS: Ultradwarf bermudagrass cultivars are currently the preferred grass used for putting greens in the southeastern United States. In this setting, ultradwarf bermudagrasses (UDB) exhibit high shoot density, fine leaf texture, and rapid recovery that facilitate lower mowing heights. While these traits are highly desirable, they result in challenges of excessive thatch accumulation that can be detrimental to plant health and sustainability. A second challenge is maintaining healthy root systems. Vertical mowing, sand topdressing, and aerification play an integral role in thatch management, root health, and turfgrass quality. Light, frequent vertical mowing or an aggressive, infrequent vertical mowing, both followed by sand topdressing are management practices for thatch control. Cultivation studies were initiated on Miniverde and Champion UDB putting green surfaces. Parameters used to evaluate turfgrass response included a baseline measure (prior to application of treatments) of organic matter and soil pH (twice per year); turfgrass quality and color, soil moisture, and foliar disease (assessed bimonthly June to November 2012); speed and firmness of putting green surfaces (monthly); depth of thatch, root disease and architecture (alternating months throughout the duration of the two-year study). Seven cultivation treatments were evaluated and included a weekly vertical mowing, weekly vertical mowing with a once per month substitution of slicing, spiking or scarifying. The remaining treatments consisted of single slicing, spiking, or scarifying applications once per month. The surfaces were sand top-dressed weekly. Each treatment was divided to receive a seasonal fungicide program or no fungicides. The study was arranged as a randomized complete block split plot design. The main plot factor is cultivation treatment and sub-plot factor is the presence or absence of fungicide. PARTICIPANTS: Mr. Phillip Vines, graduate research assistant at the Master's of Science level is participating in this research. Mr. Robert Glenn and Ms. Tristan Green are undergraduate student workers also participating in the research. Dr. Frederico Hoffman is collaborating on the phylogenetic lineage of the ectotrophic root infecting fungi. TARGET AUDIENCES: Golf course superintendents throughout the southeastern U.S., sports field turfgrass managers PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Area under the depth of thatch progress curve in response to cultivation practices was similar as well as root health in Champion or Miniverde putting green surfaces. Differences in surface firmness were noted in the Champion putting green. Treatments that consisted of weekly vertical mowing with a monthly substitution of slicing, scarifying, or spiking developed significantly firmer surfaces compared to the single, monthly application of slicing, scarifying, or spiking. Differences in firmness of the Miniverde putting green surface were not observed; however, green speed, measured by ball roll distance, was greater in treatments receiving weekly cultivation. The inverse results were observed for turfgrass quality in both putting greens. Turfgrass quality was reduced in those treatments that received weekly cultivation compared to the single, monthly cultivation treatments. These results reflect the plant damage caused by weekly cultivation practices over a growing season. The treatments with minimal surface disruption, single monthly cultivation, had improved turfgrass quality but the surface was soft, creating a less than desirable putting green in terms of playability. Leaf spot caused by Bipolaris spp. and dollar spot (Sclerotinia homoeocarpa) appeared sporadically on the putting greens throughout the 2012 growing season. The leaf spot severity progress curve was greater on Champion in plots that did not receive the seasonal fungicide program. The dollar spot progress curve was greater on Miniverde in plots that did not receive the seasonal fungicide program. Foliar diseases were also more severe in plots receiving weekly cultivation practices which may also negatively impact turfgrass quality. Ectotrophic root-infecting (ERI) fungi have been reported as pathogenic on cool-season grasses maintained as putting greens causing significant root rot and turf dieback. When assessing root health, fungi characteristic of ERI fungi were observed colonizing the roots. To determine their identity and role in root health, these fungi were isolated in pure culture and identified using molecular techniques that included polymerase chain reaction (PCR) of the internal transcribed spacer (ITS) region or species specific primers when appropriate. The identity of the selected ERI from UDB roots were 95 precent similar to major ERI pathogens of cool-season putting green turf such as Magnaporthe poae. PCR using species specific primers for M. poae did not result in a match. A preliminary phylogenetic analysis was constructed using Mega5 software. The position of three selected ERI isolates from UDB displayed relatedness to M. poae, but diverged into a single clade indicating possible new species of Magnaporthe. Preliminary pathogenicity studies were conducted that resulted in reduced root health and mass in those UDB exposed to selected ERI. One abstract, three oral presentations at scientific/professional meetings, and two presentations to stakeholders were delivered in 2012.
Publications
- Bermudagrass putting greens: A closer look at the root of the problem. 2012. P. L. Vines, M. Tomaso-Peterson. Phytopathology 102:S4.128.
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Progress 01/01/11 to 12/31/11
Outputs
OUTPUTS: A two-year field study was initiated June 2012 on a research putting green established with the ultradwarf bermudagrass varieties Miniverde and Champion. The goal of this research is to develop a cultivation program for ultradwarf bermudagrass (UDB) using True-Surface Greens Care equipment that reduces thatch, maintains firmness and smoothness of the putting surface, and improves root health while minimizing associated stress that leads to prolonged recuperation and diseases. The cultivation practices consist of weekly vertical mow alternated with a monthly application of deep slicing, spiking, or scarifying, with the latter three as a single monthly treatment as well. A seasonal fungicide program is applied monthly as a sub-plot treatment. The putting green is fertilized, irrigated, and treated with a PGR according to management practices for UDB. To determine treatment effects, organic matter content, soil pH, and soil nutrient composition are analyzed in June and November of each year. Non-compressed thatch depth, root health, and root architecture are recorded alternating months on an annual basis. Bimonthly turf quality and disease ratings and volumetric water content are recorded. Surface firmness and greens speed are measured monthly with the Tru-Firm Device and modified stimp meter, respectively. Simultaneous to cultivation practices, ectotrophic root infecting fungi (ERI) are isolated from asymptomatic roots of UDB to determine their role in plant health as well as identify these specific fungi. To date, a cultivation demonstration of True-Surface Greens Care equipment on Ultradwarf bermudagrass putting greens as well as the operation of the Tru-Firm Device was conducted at the Mississippi State University Turfgrass Field Day and Equipment Expo, 26 June 2012. An oral presentation, Bermudagrass Putting Greens: Getting to the Root of the Problem, was presented at the American Phytopathological Society Meeting, Providence, RI 7 August 2012. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Root production and overall plant health will be improved when slicing, spiking, or scarifying practices are applied to UDB greens. These cultural practices have yet to be evaluated on UDB and it is theoretically possibly that they may increase oxygen flux to UDB roots, thereby helping to maintain a more productive root system. This in turn would result in healthier shoots, improved photosynthesis as well as other physiological benefits, water use efficiency, and reduce thatch in which pathogens reside. We will determine if these novel cultivation practices can sustain turf health and reduce the reliance on a seasonal fungicide program. On the consumer side (noting that golfers often demand perfection), the aforementioned cultivation practices may improve the putting green surface (increase ball speed) and may increase the number of rounds of golf that can be played on a course in a given year, which would be a financial benefit to the various golf courses and the economy of the state of Mississippi in general. A graduate student will conduct this proposed research as partial credit towards a degree. Sustainability of UDB is vital. Reduced reliance on fungicide use, increased water efficiency, and increased longevity of a functional UDB putting green surface are small steps in the overall goal of environmental stewardship and sustainability in the golf course industry. Preliminary results indicate ERI fungi associated with root rot of ultradwarf bermudagrass are not currently identified. Future work will focus on their identification, pathogenicity, and phylogenetic analysis.
Publications
- No publications reported this period
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