Presentation Abstracts – Turfgrass Trends for Changing Times

North America 2026 World Cup – Challenges and Opportunities

J.N. Rogers, III and J.C. Sorochan

Michigan State University and University of Tennessee

The 2026 FIFA World Cup will be the largest to date, as it will be co-hosted by three
countries for the first time: Canada, the United States of America, and Mexico. In contrast to the usual 32 teams, a total of 48 teams will participate in the 2026 World Cup, necessitating an increase to 16 host cities. The main challenge from FIFA is to maintain the consistency and uniformity of the playing surface across these 16 stadiums, eight of which feature artificial surfaces, and five of these eight are considered indoor stadiums. All World Cup matches are mandated to be played on natural grass surfaces, with 2026 venues requiring either cool or warm season species. Two universities – Michigan State University and the University of Tennessee –have collaborated and undertaken the FIFA-funded task of finding solutions for the unique demands of the 2026 World Cup. A significant focus of the research, beginning in 2021, has addressed the challenge of designing, installing, and maintaining a natural turfgrass pitch for the five indoor stadiums. Converting these pitches into a conventional grass playing surface is cost-prohibitive, as pitches will most likely revert to artificial turf after the World Cup. To tackle this challenge, researchers have proposed the development of a temporary shallow profile playing surface that can be installed just prior to use and then removed quickly after the matches. The shallow-profile system will utilize the advancement of sports turfgrass, incorporating elements such as big roll sod on plastic, root zone stabilizers, shock pads, portable drainage mats, and grow lights. The innovations resulting from this research will continue the advancement of sports turfgrass science and will have a broader impact not only benefiting soccer, but also extending to other sports.

• Sustainable Water Management – Dr. Grady Miller, Professor and Extension Specialist

Drought conditions in some parts of the country seem more common these days than ever. These often cause state and local governments to implement ordinances to limit or prohibit the use of irrigation water for various turfgrass areas. As water restrictions become more common, or for those turfgrass managers that want to more efficiently manage irrigation, greater knowledge of turfgrass water needs is essential to maintaining healthy turfgrass stands with as little water as possible. My research program has been evaluating water consumption by species and cultivars. This research has tested germplasm under drought conditions as well as determined crop coefficients. Results will highlight drought tolerance among the turfgrasses as well as present techniques that can be further utilized to evaluate
drought tolerance in new germplasm.

• Approaches for Precision Turfgrass Fertilization Management – Qiyu Zhou, Assistant Professor, Turfgrass Management

Proper fertilization, especially with nitrogen (N), is crucial for effective turfgrass management. The rate of turfgrass growth serves as a valuable indicator of cultural practices and environmental conditions, enabling the effective adjustment of fertilization programs and plant growth regulator (PGR) applications. Unfortunately, limited research exists, especially for warm-
season grasses, on the relationship between turfgrass growth rate, turfgrass performance, and cultural practices. This has resulted in a lack of guidance for leveraging growth rate to improve management practices and maximize resource use efficiency. Our ongoing field research aims to address these knowledge gaps by focusing on understanding the growth rate of
bermudagrass on putting greens. The ultimate goal of this project is to investigate the influence of cultural practices, including mowing height, N fertilization, and PGRs, and environmental conditions including weather, traffic, and soil water content on bermudagrass growth rate. Furthermore, we will identify the optimal growth rate range for bermudagrass putting greens to
maximize turfgrass quality and playability, with consideration given to regulating soil organic matter content. We will also develop a machine-learning-based growth rate prediction model and evaluate the feasibility of using this model to inform N application decisions and optimize the timing of PGR treatments. Through this research, we aim to provide valuable insights and practical recommendations for enhancing the quality and performance of putting greens while optimizing resource utilization.

• Introducing Middle School Youth into the World of Turfgrass Through and Interactive 4-H Curriculum – Matthew Clay, County Extension Agent, and Liz Driscoll, 4-H Specialist

Science, technology, engineering, and math (STEM) literacy is critical to the United State’s future success (National Science Board, 2018). According to the U.S. Department of Commerce (Noonan, 2017), STEM occupations are growing at 17% with STEM workers playing a key role in sustained growth and stability of the U.S. economy. STEM education creates critical thinkers, increases science literacy, and enables the next generation of innovators. The study of turfgrass provides a rich context for youth to build these skills as well as explore a diversity of concepts like populations and ecosystems, regulation and behavior, and structures and functions of living things. These broad objectives are universally taught in middle school science throughout the country but no materials exist to build student knowledge using a framework of hands-on discovery with turfgrass. To this goal, North Carolina 4-H has developed a curriculum brimming with hands-on activities centered on turfgrass to engage middle school youth in understanding turfgrass science and management. This project has trained Extension professionals and community partners to deliver these engaging, experiential turfgrass lessons with middle school youth showing a positive increase in STEM self-efficacy and interest in careers related to turfgrass.

• The Influences of Nitrogen Fertilization and Edaphic Factors on Take-All Root Rot Incidence – Brandi Merrick, MS student, Turfgrass Pathology

Take-all root rot (TARR) is a problematic disease of ultradwarf bermudagrass golf course putting greens. It is the most diagnosed disease of bermudagrass managed for putting greens at the North Carolina State University Turf Diagnostics Lab. The causal agents of take-all root rot, as well as some methods of fertility and chemical management have been well documented. Despite that, turfgrass managers are not observing the disease control expected from proper fungicide applications and maintenance practices. In this project, one study conducted nitrogen fertility trials comparing various nitrogen rates and sources. A significant difference was observed between nitrogen rates and sources when compared to a non-treated control. In a second study, golf courses across the United States that have documented TARR and those without TARR documented were surveyed. Soil samples and irrigation water samples were collected and analyzed for pH, mineral nutrition, percent organic matter, and salinity. Locations with no take-all root rot incidence had substantially lower concentrations of phosphorus, magnesium, and manganese in the soil. Interestingly, no significant differences were found in the percent organic matter of the top two inches of soil between all courses. However, there was a slightly higher percent organic matter in the bottom two inches from locations that have not observed TARR. These results have the potential to provide alternative options for turfgrass growers managing take-all root rot by adjusting mineral levels in the soil.

• Optimizing tissue culture protocols in warm-season turfgrass species for genetic engineering applications – Esdras Carbajal, PhD student, Turfgrass Breeding

Esdras M. Carbajal, Hsuan Chen, Robert Thomas, and Susana R. Milla-Lewis

Genetic engineering holds immense promise for enhancing breeding efforts in warm-season turfgrass species, offering opportunities for improved stress tolerance and disease resistance, among other traits of interst. However, the successful implementation of genetic engineering techniques relies heavily on the development of efficient tissue culture protocols for the development of callus tissue. In 2022, the Turfgrass Breeding and Genetics Program at NC State University initiated efforts to optimize tissue culture methodologies specifically tailored to warm-season turfgrass species to ensure their reproducibility and scalability for genetic engineering applications. Several experiments have been completed for St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] and zoysiagrass (Zoysia spp.) to evaluate key parameters such as explant selection, sterilization procedures, hormone concentrations, and culture media composition. In both species, evaluation of 16 different combinations of synthetic auxin and cytokinin concentrations identified specific treatments that resulted in significantly higher numbers of calli developed. Likewise, explant type and age had a significant effect on calli recovery.  Additionally, preliminary results indicate we have identified treatments that successfully induce somatic embryogenesis in zoysiagrass. The protocols developed here will be evaluated in other economically important warm-season turfgrass species like bermudagrass and centipedegrass.

• Characterization of Non-Target Site Resistance Mechanisms of ALS Resistant Annual Bluegrass (Poa annua L.) – Trip Rogers, PhD student, Pesticide Fate

Herbicide-resistant weeds with non-target site resistance mechanisms (NTSR) are a growing threat, as cross-resistance and multiple resistance to herbicides with differing mechanisms of action (MOA’S) become more prevalent. The majority of the NTSR and target-site resistance (TSR) have been identified over the past few decades as a response to selection pressure through herbicide use. Annual bluegrass (Poa annua L.) is a problematic weed in turfgrass systems. The growth characteristics of this species coupled with herbicide resistance to multiple MOA’s increases agronomic, economic, and social pressure on turfgrass managers. Trifloxysulfuron is a post-emergent acetolactate synthase-inhibiting (ALS) herbicide used to control broadleaf and grassy weeds as well as sedges in select turfgrass systems. Studies were conducted to identify if NTSR mechanisms were present in six annual bluegrass populations resistant to ALS-inhibiting herbicides. Populations were collected from the Southeastern United States and underwent a preliminary and full dose rate titration to confirm resistance. Once resistance was confirmed, absorption and translocation experiments utilizing 14C-trifloxysulfuron were conducted to investigate potential NTSR mechanisms. A population from Virginia exhibited reduced 14C-trifloxysulfuron absorption (25.7%) when compared to the susceptible population (38.3%) at 24 HAT. Similarly, at 96 and 192 HAT the Virginia population absorbed 15.5% and 13.6% less 14C-trifloxysulfuron when compared to the susceptible population. Furthermore, reduced translocation was observed in populations collected from Florida, Georgia, and South Carolina when compared to the susceptible population. These data suggest that reduced absorption and translocation may contribute to resistance in select populations screened.

• The Physiological Basis of Drought Tolerance in Zoysiagrasses – Emma Simpson, MS student, Turfgrass Physiology

Emma Simpson, Matthew Taggart, Esdras M. Carbajal, Susana R Milla-Lewis, and Amanda A Cardoso

Turfgrass is widely used in sport fields, lawns, and roadside covers. Zoysiagrasses are warm-season grasses growing well under higher temperatures and low rainfall. In this study, we assessed the drought tolerance of three economically important zoysiagrasses: Meyer (Z. japonica), Zeon (Z. matrella), and Lobo (Z. japonica x Z. matrella). Meyer and Zeon are longstanding commercially important species. Meyer for its cold hardiness and Zeon for its drought tolerance and fine texture. Lobo is a newly released cultivar from NC State University with a high drought tolerance. First, we characterized the cultivars in terms of leaf gas exchange and leaf green levels. Then, we investigated whether these parameters would be affected by drought in a similar way across cultivars. A severe drought was then induced by withholding irrigation for 11 days and post-drought recovery was assessed for 11 days by maintaining irrigation. Well-watered plants of the three cultivars had similar leaf gas exchange but Lobo had a greater greenness index – a trait highly desirable in turfgrass for commercial purposes. After 11 days of drought, leaves from all three cultivars were completely rolled and had substantial canopy mortality. They also exhibited a considerable reduction in greenness such that the difference in the greenness index between Lobo and the other cultivars disappeared. At the end of the drought, the three cultivars also completely stopped photosynthesis and reduced evapotranspiration by 90% compared to the initial values. Lobo reduced evapotranspiration faster, but after 11 days, all three cultivars exhibited similar evapotranspiration. Upon rehydration, Lobo and Zeon recovered the greenness index faster than Meyer, but after 11 days of recovery, all three genotypes had similar greenness. The post-drought levels of greenness did not return to the pre-drought levels after 11 days. All three cultivars recovered from drought in a very similar way in terms of photosynthesis and evapotranspiration. Overall, no singular cultivar exhibited a high tolerance during this severe drought, however, Lobo exhibited some interesting characteristics, such as faster reductions in evapotranspiration and faster recovery of greenness levels upon rehydration.

• Determining the genetic diversity of 288 accessions of St. Augustinegrass – Ty Thomas, PhD student, Crop Genomics

Ty Thomas,

St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] is extensively used in lawns and commercial landscapes around the Southeast, particularly in coastal regions given its preference for warm and moderate temperatures. Genomics-assisted breeding techniques can help the NCSU Turfgrass breeding program improve cold tolerance and drought resistance to increase the geographical range of the crop. To enable this, we have performed high-depth, whole genome sequencing of 288 diverse St. Augustinegrass accessions and are working to catalog sequence diversity within the species. Characterizing the genomic diversity in the germplasm will likely be challenging given the varying levels of ploidy within the species. We attempted to confirm pre-determined ploidy levels using reference-free k-mer-based ploidy predictor tools. Without access to a reference genome, this proved to be difficult and ultimately inaccurate. Determining ploidy levels is important not only for establishing the sequence diversity but also for informing breeders of sexual compatibility between accessions. Compared to diploids, polyploid genotypes show many improved traits including faster growth, improved cold tolerance, and increased biotic resistance. Thus, these data/resources will serve as a launching point for informing vigorous crosses between compatible accessions of different ploidy and will enable future implementation of genomic selection schemes to shorten the breeding cycle.

• Response of root- associated microbial community of Bermuda and Zoysiagrass under compaction in turf field – Sayada Momotaz Akther, Soil Microbiology

Maintaining athletic field turf poses substantial challenges, and soil compaction has emerged as a primary stressor affecting turfgrass health. The root microbiome, comprising diverse microbial communities and their associated genes, plays a vital role in enhancing plants’ ability to withstand abiotic stressors. In this study, we investigated the response of the microbial communities of two turfgrass species, bermudagrass and zoysiagrass, to soil compaction in different microhabitats, including the root endosphere, rhizosphere, and bulk soil. High-throughput amplicon sequencing was employed to analyze the diversity, abundance, and composition of bacterial and fungal communities. Intact grass-soil cores were collected in 2021 from 12 cultivars for each grass type
grown in a field trial under compaction. The field trial was established in 2019 and compaction treatments were applied three to four times per week mimicking six professional football games per week. Bermuda and zoysiagrass under no-compaction were also sampled as the control. By utilizing marker genes such as 16S rRNA for bacteria and ITS for fungi, we will gain insights into the impact of soil compaction on the turfgrass root microbiome. Understanding the response of root microbiome to soil compaction can inform management practices that promote favorable plant-microbe interactions and enhance turfgrass health in the presence of soil compaction.

• Strategies for Emerging Turf Insect Pests – Dr. Terri Billeisen, Extension Associate, Turfgrass Entomology

Changes in product selection, mode of action, application rate, and cultural practices have influenced the breadth of insect pests we manage in turfgrass. As products become increasingly target-specific, new and different arthropod and annelid pests such as annual bluegrass weevil, hunting billbug, ground pearls, mites and earthworms are causing damage in managed turfgrass areas. My research program has examined cultural, biological and chemical options for management of many of these pests. Specifically, we have observed insect ecology and behavior and determined how factors such as life stage timing can impact our selections for management. In this presentation, we will focus on the annual bluegrass weevil (Listronotus maculicollis) and how management approaches have been improved as a result of this work.

• Adventures in Keeping Grass Green: Turfgrass Pathology Updates – Dr. Jim Kerns, Professor, Turfgrass Pathology

Diseases can ravage turfgrasses grown throughout North Carolina. Our program focuses on the etiology, epidemiology, and management of diseases of both warm- and cool-season grasses. Primarily the program has focused on root disease epidemiology and management because 68% of all samples submitted to the Turfgrass Diagnostic Lab are root diseases. This presentation will detail efforts to understand diseases such as Pythium root rot, Take-all root rot and fungicide movement into the root zone. We have identified the causal agents of Pythium root rot and take-all root rot and when those causal agents infect the roots of turfgrasses. Research demonstrating that fungicides do not readily move into soil has aided turfgrass managers with combating these diseases especially when the fungicides are applied at the appropriate timing. The efforts of the program have limited the impact of root diseases for turfgrass managers in NC and beyond.

• Exploring Molecular Tools for Weed Control and Necessary Steps for Adoption in Turfgrass – Dr. Ramon Leon, Professor and University Faculty Scholar of Weed Biology and Ecology

Public concern regarding the use of herbicides in urban areas (e.g., golf courses, parks, lawns) is increasing. Thus, there is a need for alternative methods for weed control that are safe for the public, effective against weeds, and yet selective to turfgrass and other desirable species. New molecular tools such as RNA interference (RNAi) have potential to meet all those requirements. At NCSU, we are developing a RNAi systems that can control control weeds reducing the need for synthetic herbicide use. Furthermore, our program is generating data to understand the perceptions of key stakeholders to facilitate adoption as well as regulatory processes. Development of this type of innovative solutions for weed management may increase sustainability while maintaining quality in turfgrass systems.