Golf course superintendents use plant growth regulators (PGRs) to suppress growth, enhance turfgrass quality, save water, and maintain healthier, more resilient putting greens. Applicators often tank-mix PGRs with micronutrients (Fe, Mn, Zn), macronutrients (Ca, Mg), or use spray water high in Ca and Mg (e.g., well water). These elements are divalent cations that can potentially interact with spray solutions. Although the effects of tank-mixing divalent cations with herbicides are well-documented, their effects on PGR performance are not. The objective of this study was to determine the effects of Ca, Fe, Mg, Mn, and Zn in spray solutions on the efficacy of trinexapac-ethyl (Primo Maxx; Syngenta) when applied to hybrid bermudagrass. The results demonstrate that Primo Maxx effectively suppresses growth when tank-mixed with divalent cations, allowing golf course managers to safely combine the PGR with micronutrients or apply it in hard water without compromising performance.

Mulch, mechanical removal, and herbicides are the most common weed control practices employed in landscapes. Previous research demonstrated preemergence herbicide efficacy in nurseries, but research in landscapes with and without mulching is limited. This research evaluated formulations of common preemergence herbicides for weed control in bare soil and mulched landscapes in Florida, Indiana, and Ohio in 2022. Herbicide treatments included liquid (spray-applied) and dry (granular) formulations of flumioxazin, isoxaben + trifluralin, dimethamid-p + pendimethalin, prodiamine + isoxaben, indaziflam, and isoxaben + dithiopyr. Treatments were applied once in Indiana and Ohio, while Florida sites received sequential applications 4 months apart. In mulched sites in Indiana and Ohio, no main effect or herbicide-by-formulation interaction impacted weed cover at 2 months after treatment. In bare soil at these locations, all herbicide treatments had less weed cover (35%-52%) compared to the nontreated control (98%), except dry-applied flumioxazin (88%) and dry-applied indaziflam (74%). In the two Florida mulched sites, liquid-applied indaziflam and both formulations of flumioxazin and dimethenamid-p + pendimethalin had lowest weed cover at 2 months after the second treatment (<23%). All other treatments had weed cover (30%-39%) similar to the nontreated control (39%). This research demonstrated mulching to be more effective than preemergence herbicides in Indiana and Ohio. However, preemergence herbicides are important when mulch is omitted or in mulched sites with high weed pressure. Most herbicides tested were effective with some liquid-applied herbicides enhancing weed control.

ABSTRACT Understanding weed biology, particularly factors influencing seed germination, can help develop effective weed management strategies. This research evaluated the effects of temperature, light, and water stress on the germination of Kyllinga gracillima (false green kyllinga). Seeds collected in Indiana (IN) and New Jersey (NJ) were subjected to constant (20°C) and alternating temperatures (15/5°C, 20/10°C, 25/15°C, 30/20°C, and 35/25°C; day/night) and different water potential conditions in germination chambers. By 42 days after initiation (DAI), total germination exceeded 90% at 20/10°C, 25/15°C, 30/20°C, and 35/25°C, but no seeds germinated at 15/5°C in either population. At a constant 20°C, germination was reduced compared to seeds germinating in alternating temperatures (25/15°C). Seeds subjected to 21 days of dark had 46% (IN) and 2% (NJ) germination compared to > 94% (IN and NJ) germination of seeds exposed to light. Water stress significantly reduced germination, with no germination occurring at −0.4 MPa. By 42 DAI, germination was 97% at 0.0 MPa, 96% at −0.1 MPa, 77% at −0.2 MPa, and 16% at −0.3 MPa. The results indicate that alternating temperatures and light exposure promote germination, while reduced water potential suppresses it. Results suggest that management practices that create dense turfgrass swards coupled with infrequent irrigation will reduce K. gracillima establishment from seeds. These findings support integrated management strategies combining cultural practices with chemical control, and they warrant field validation of these approaches.

Poa annua L. is a widespread and persistent weed in managed turfgrass systems, exhibiting both annual and short-lived perennial growth habits. Effective management requires an integrated approach, with chemical herbicides remaining a primary tool. This review outlines the current landscape of chemical control strategies, including pre-emergence and post-emergence herbicide options, plant growth regulators, and emerging chemistries. Herbicide resistance in Poa annua continues to pose a significant challenge, with confirmed cases spanning multiple modes of action. Consequently, sustainable management depends on rotating herbicide classes, using mixtures and sequences of treatments, and integrating nonchemical tactics. Continued research into novel herbicide modes of action, application technologies, and integrated weed management approaches will be critical for maintaining long-term control of Poa annua across diverse turfgrass systems.

Alternative cultural methods, such as the selection of a turfgrass species and cultivars, need to be investigated as a weed control tactic since certain turfgrass species/varieties demonstrate potential for weed suppression. The objective of this experiment was to assess the allelopathic potential of common warm-season turfgrass species ( Eremochloa ophiuroides ,  Stenotaphrum secundatum , and  Zoysia japonica ) on common turf weeds ( Digitaria sanguinalis ,  Eleusine indica , and  Poa annua ). Greenhouse and laboratory experiments were conducted to evaluate the effect of turfgrass competition, leaf extracts, and soil leachates on the germination and growth of weed species. Leaf extracts were more effective in suppressing weed species germination and growth than soil leachates. Zoysiagrass leaf extracts reduced the germination of P. annua by 16% and the coleoptile length of E. indica L. by 47% compared to deionized water control. Turfgrass species’ leaf extract stimulates annual bluegrass's coleoptile growth while inhibiting its radicle growth. Warm-season turfgrass soil leachates did not suppress the germination and radicle growth of weed species.  Eremochloa ophiuroides soil leachates were effective in suppressing  D. sanguinalis  coleoptile length. In this experiment, limited allelopathic effects of turfgrass species were noted.  Poa annua  germination and growth were reduced in a densely established turf, indicating that turfgrass species were equally inhibitory when competition was present. These results suggest that maintaining a dense and strong turf sward that can outcompete weeds for light, nutrients, and water is a more successful weed management technique than selecting a turfgrass species based on potential allelopathic effects.

Enhancing soil carbon (C) sequestration helps reduce atmospheric carbon dioxide concentrations. Turfgrasses are important crops in the urban environment and have shown potential for C sequestration. However, little is known about how turfgrass species selection affects soil C concentration or how this varies over time. The objectives of this research were to evaluate the effect of three turfgrass species, sward age, and soil sampling depth on total soil C and N, soil organic matter (SOM), and labile soil C. A total of 25 locations throughout Indiana were sampled from established swards of Kentucky bluegrass ( Poa pratensis L.), tall fescue [ Festuca arundinacea  Schreb.; syn.  Schedonorus arundinaceus  (Schreb.) Dumort., nom. cons.], and zoysiagrass ( Zoysia japonica Steud.) with varying sward age. Turfgrass species affected soil total C and labile C concentrations but had no effect on soil total nitrogen (N) or SOM. Differences between the C pools of soils under turf 0–10 years in age compared to those 11–25 years in age only occurred near the soil surface. As turf swards age, total soil C, total soil N, and SOM increased near the soil surface (0- to 7.5-cm depth) and little beyond the 7.5 cm in depth. The strong relationship ( p  ≤ 0.0001, R 2  > 0.57) between total N, SOM, and labile C highlighted their interplay in the mineralization of N from SOM and changes in the short-term C pool of a turfgrass system.

Zoysiagrass ( Zoysia spp. Willd.) produces a high-quality warm-season turfgrass sward and requires fewer management inputs compared with many other warm-season turfgrass species. Three primary species, all known by the common name “zoysiagrass,” are used in the United States, and these include Z . japonica , Z . matrella , and Z . pacifica . These three zoysiagrasses are distinguished from one another based on stress tolerance differences, visual characteristics, and their geographic distribution. Together, all of these factors influence the breeding, production, and distribution of zoysiagrass sod in the US production, and distribution of each species is typically transitional, warm-humid, and warm-arid climatic zones ( Z . japonica ); warm-humid, and warm-arid climatic zones ( Z . matrella ); and warm-tropical climate zones ( Z . pacifica ). This review summarizes the knowledge of the current zoysiagrass sod market and research related to the establishment, management, weed control, and harvest and transplanting of zoysiagrass sod and identifies the knowledge gaps and future research needs. Compared with bermudagrass ( Cynodon spp. Rich.), zoysiagrass research is lacking, especially related to sod production. Future research on zoysiagrass should focus on establishment, post-planting management, quantifying management inputs, and practices to hasten sod production times, and improve transplant success. Additionally, more research is needed on weed control during establishment and production. Because of its wide adaptation and genetic diversity, research should be conducted in multiple climates across a diversity of cultivars to aid sod producers and end-users.

‘XZ 14069’ (Reg. no. CV‐297, PI 707001), marketed as “LOBO”, is a fine‐textured zoysiagrass ( Zoysia spp.) hybrid with excellent turfgrass quality and stress tolerance developed and released by the North Carolina Agricultural Research Service, Raleigh, NC. XZ 14069 was developed in 2014 through artificial hybridization between Zoysia japonica ‘Meyer’ and Z . japonica × matrella interspecific hybrid ‘Victoria’. After evaluation in nurseries (2014–2016) and roadside trials (2015–2018) in North Carolina for establishment rate and turfgrass quality under low inputs, XZ 14069 was advanced to i) Specialty Crop Research Initiative multi‐environment trials (Citra and Jay, FL, Dallas, TX, Griffin and Tifton, GA, Jackson Springs, NC, Riverside, CA, and Stillwater, OK), ii) US Golf Association low input trials (West Lafayette, IN, Raleigh, NC, Tifton, GA, Stanfield, AZ, and Escondido, CA), and iii) National Turfgrass Evaluation Program (NTEP) low‐input warm‐season trials (Jay, and Citra, FL, Starkville, MS, Raleigh, NC, Las Cruces, NM, Stillwater, OK, College Station, TX, Logan, UT, and Virginia Beach, VA). Additionally, the line was evaluated in ancillary trials for sod quality (Jackson Springs, NC), salinity tolerance (Riverside, CA), shade tolerance (Citra, FL, and Stillwater, OK), and large patch resistance (Raleigh, NC). XZ 14069 exhibits fast establishment, can retain acceptable color and turfgrass quality under very low inputs, has resistance to large patch disease, and possesses drought, salinity, and shade tolerance. The cultivar is not limited to low‐management areas such as golf course roughs or roadsides, as its superior turfgrass quality under regular management makes it suitable for higher‐end uses like lawns and golf course fairways.

Maintaining turfgrass quality is key to deriving ecological, social, and cultural ecosystem services from urban sports fields. Annual bluegrass, the most troublesome weed in U.S. turfgrass systems and a problematic weed in Australasia and Europe, poses serious risks to sustaining these services. Recent U.S. focus groups have documented turfgrass professionals' concerns about annual bluegrass, particularly the evolution of herbicide resistance and opportunities for improved management. However, comprehensive scientific data have been lacking to test the scale and depth of the concerns and identify significant factors affecting turfgrass manager decisions to adopt remedies. The purpose of this study is to help fill those gaps in scientific knowledge with findings from the first national survey of U.S. sports and recreation turfgrass professionals. Integrated weed management (IWM), a holistic weed management approach that blends chemical and non-chemical practices, is key to slowing the evolution of herbicide resistance, but it meets stiff challenges in practical application. A multivariate regression model tested for factors hypothesized to affect the count of diverse practices used by U.S. sports turfgrass managers. Significant positive influences on practice adoption include the number of employees in a sports field operation, degree of concern about herbicide resistance, Extension educational program attendance, and length of tenure in the sports sector. Insufficient time, a perceived lack of non-chemical options, and a higher education level decrease the total count of practices. The findings support three actions to advance IWM for sports turfgrass:

Zoysiagrass (Zoysia spp. Willd.) is a warm-season grass used from tropical to temperate climates, and it generally requires fewer inputs than most other cool- and warm-season turfgrasses. The development of new zoysiagrass cultivars has increased its use in the United States, but its adaptation and specific uses are species and cultivar dependent. The playability of zoysiagrass and reduced inputs required to maintain this species have made it a popular choice for golfing surfaces. The greatest threat to zoysiagrass health and survivability is winterkill. This management guide discusses winterkill: what it looks like, what causes it, and where it occurs. Additionally, this management guide describes best management practices for the prevention and recovery of zoysiagrass from winterkill damage.

Turfgrasses are those grasses that tolerate frequent mowing. The act of mowing turfgrasses, primarily lawn mowing, has received much negative attention primarily due to its labor requirement and the resulting mower emissions. This paper provides a comprehensive review of the benefits and drawbacks of mowing grasses, specifically turfgrasses used on lawns, parks, golf courses, and sports fields, using an ecosystem services and disservices framework. Discussed is the challenge of creating a “one-size-fits-all” approach to selecting the best mowing management practices and sociocultural tensions that exist related to lawn mowing. Discussion also includes the benefits and value gained from mowing turfgrass and strategies to mitigate ecosystem disservices that result from mowing.

Large patch (LP), caused by Rhizoctonia solani anastomosis group (AG) 2-2LP, is the most impactful disease that affects zoysiagrass (Zoysia spp.). Currently, there are no resistant cultivars on the market, and the only effective means of control is the application of fungicides. Breeding efforts to develop cultivars with resistance to LP would benefit from an increased understanding of the genetic control of the trait. In this study, an F1 mapping population containing 179 progeny was developed from crosses between Zoysia japonica 'Meyer' (susceptible parent) and Z. matrella plant introduction 231146 (resistant parent). Paternal (AH) and maternal (HA) linkage maps were generated using single-nucleotide polymorphism markers developed from genotyping-by-sequencing analysis. Both AH and HA maps organized into 20 linkage groups and consist of 639 and 817 markers, respectively. LP response was evaluated across four experimental runs through collection of final disease severity, digital image analysis-derived percent incidence, and the area under the disease progress curve. All traits showed significant variance among the population, and genotype and genotype × run effects were found to be significant. Sixteen quantitative trait loci (QTLs) associated with resistance were identified, explaining 2.24 to 10.3% of the total phenotypic variance. After looking for overlap across traits, a potential LP "hotspot" was found on linkage group AH_13 (34.5 to 48.6 cM). Several resistance genes were identified near peak markers. The QTLs and associated markers identified in this study have great potential to be introgressed in breeding populations for the development of LP-resistant zoysiagrass cultivars.

Poa annua L. is one of the most widespread and troublesome weeds of turfgrass. It persists as both an annual and perennial and is adaptable to almost any static maintenance regime, including adaptation to mowing heights and evolution of herbicide resistance. This management guide is intended to provide stakeholders with a summary of new and existing knowledge on integrated Poa annua management. Here we review the basic biology and ecology, as well as practical integrated weed management (IWM) strategies developed for its control.

Thatch is an intertwined layer of dead and living stems and roots that accumulates in turfgrass when organic matter production outpaces decomposition, affecting turfgrass quality and playability. This study evaluated thatch accumulation and performance of various zoysiagrass ( Zoysia spp.) genotypes across six locations (Olathe, KS, USA; Stillwater, OK, USA; West Lafayette, IN, USA; Dallas, TX, USA; and Davie and Citra, FL, USA) for the National Turfgrass Evaluation Program (NTEP) and United States Golf Association (USGA) trials. Thatch accumulation in the NTEP trial was measured 5 years after planting, while the USGA trial was assessed 3 years after planting. The objectives were to 1) evaluate thatch accumulation across cultivars and breeding genotypes and 2) evaluate the correlations between zoysiagrass thatch depth vs. other genotype morphological traits. Thatch depth, thatch mass, turfgrass quality, and other traits were measured across locations. In the NTEP trial, significant differences in thatch depth among cultivars were observed only in Dallas, TX, where ‘Emerald’ had the highest thatch depth (0.73 inch) and ‘Meyer’ and DALZ 1808 had the least (<0.35 inch). The USGA trial showed no significant thatch depth differences in Olathe, KS, and West Lafayette, IN, but minor variations were noted in Citra, FL. Correlations between thatch depth and other traits showed that thatch depth was negatively correlated with surface firmness at Dallas, TX, and Citra, FL, locations (NTEP trial) and with Normalized Difference Vegetation Index (NDVI) in West Lafayette, IN (USGA trial). Positive correlations with thatch depth were found with tiller numbers in Stillwater, OK; Dallas, TX; and Davie, FL (NTEP trial) and were positively correlated with the thatch mass in Olathe, KS (USGA trial). Environmental conditions could impact the performance of zoysiagrass genotypes, although these conditions were not considered in this study. The correlations noted at each location give guidance on what may impact thatch development or its influence over time.

Large patch (LP) caused by Rhizoctonia solani anastomosis group AG2-2LP is the most impactful disease that affects zoysiagrass (Zoysia spp.). Currently, there are no resistant cultivars on the market and only effective means of control is the application of fungicides. Breeding efforts to develop cultivars with LP resistance would benefit from increased understanding of the genetic control of the trait. In this study, an F 1 mapping population containing 179 progeny was developed from crosses between Zoysia japonica cultivar Meyer (susceptible parent) and Z. matrella plant introduction (PI) 231146 (resistant parent). Paternal (AH) and maternal (HA) linkage maps were generated using single nucleotide polymorphism (SNP) markers developed from genotyping-by-sequencing analysis. Both AH and HA maps organized into 20 linkage groups, and consist of 639 and 817 markers, respectively. LP response was evaluated across four experimental runs through collection of final disease severity, digital image analysis-derived percent incidence (DIAPI), and the area under the disease progress curve (AUDPC). All traits showed significant variance among the population, and genotype and genotype x run effects were found to be significant. Sixteen quantitative trait loci (QTL) associated with resistance were identified, explainning 2.24% to 10.3% of the total phenotypic variance. After looking for overlap across traits, a potential LP “hotspot” was found on linkage group AH_13 (34.5 – 48.6 cM). Several resistance genes were identified near peak markers. The QTL and associated markers identified in this study have great potential to be introgressed in breeding populations for the development of LP resistant zoysiagrass cultivar.

The application of small unmanned aircraft systems (sUAS)‐based high‐throughput phenotyping in plant breeding has advanced significantly over the past decade. Hyperspectral images and machine learning approaches offer potential to enhance drought resistance screening in turfgrass. However, large‐scale field applications remain limited, and the transition from controlled environments to real‐world phenotyping is not well understood. This study aimed to develop an sUAS‐based hyperspectral image workflow to monitor changes in turfgrass canopy reflectance during drought, validate previously reported indices from controlled environment studies in a large‐scale field study, and estimate visual turfgrass quality (TQ) from hyperspectral images. Images were collected from a zoysiagrass ( Zoysia spp.) mapping population at three dates under varying soil moisture conditions. Vegetation indices (VIs) related to light use efficiency, leaf pigments, senescence, water status, and green vegetation were computed and compared. Top‐performing genotypes under drought exhibited greater absorption in blue and red wavelengths and higher near‐infrared reflectance than poor‐performing ones. The photochemical reflectance index and plant senescence reflectance index were highly correlated with TQ ( r = 0.84 and −0.76), showed higher coefficient of variation (range 18%–37%), and had higher broad‐sense heritability (0.73–0.74) than normalized difference vegetation index (0.69), warranting their use in large‐scale field study. Machine learning models estimated TQ with a mean absolute error of 0.46. These findings highlight the importance of integrating VIs related to light use efficiency, leaf pigments, senescence, and water status to gain deeper insights into turfgrass drought response and support breeding for stress tolerance.

False-green kyllinga (FGK; Kyllinga gracillima Miq.) is a warm-season perennial weed in the Cyperaceae family. Our objective was to determine the potential for FGK to establish from seed in turfgrass. Replicated field experiments were conducted in Kentucky bluegrass (Poa pratensis L.) mowed at 6 cm. FGK was seeded at 5 or 500 kg ha(-1), and smooth crabgrass [Digitaria ischaemum (Schreb.) Schreb. Ex Muhl.] was seeded at 500 kg ha(-1). Turf was managed under either low or high input programs to generate swards of different density. Low-input turfgrass received 25 kg N ha(-1) annually, while high-input turfgrass received 200 kg N ha(-1) annually along with preventative fungicide applications. FGK establishment from seed was reduced more by turfgrass inputs than smooth crabgrass. Smooth crabgrass cover in September of both experiments was >93% and not affected by turfgrass inputs. When FGK was seeded at 500 kg ha(-1), cover in September was higher in low input (57% in Run 1, 59% in Run 2) than in high input turf (36% in Run 1, 18% in Run 2). When FGK was seeded at the lower rate of 5 kg ha(-1), cover in Run 1 was higher in the low input (14%) than high input turf (2%), but FGK cover was similar between input levels in Run 2, with 4 and 1% cover in the low and high input plots, respectively. FGK successfully overwintered in this study, with cover increasing during the second summer of growth. Although FGK is less competitive as a seedling than smooth crabgrass, its perennial life cycle allows it to increase weed cover over time.

Little research has been conducted on Cooperative Extension Service resource use and consideration among horticultural professionals. A multistate survey was created and shared through 12 University Extension programs at in-person Extension events (i.e., field days, conferences, and workshops) in the Central United States to attain a better understanding of how horticultural industry practitioners (e.g., golf course superintendents, sports field managers, lawn and landscape contractors, sod producers, nursery and greenhouse growers, tree care, and retailers) are using Extension resources, their challenges with Extension, and considerations for future use. Most professionals (74%) who attended in-person Extension events were aware of Extension resources and indicated that it was either their primary (23%) or secondary (16%) source of plant health-related information. Practitioners suggested that resources being easy to find and updated in the past 5 years were the two most important considerations for future use. Professionals who attend in-person events prefer more in-person Extension events and online Extension publications and they are more likely to use video resources and emailed newsletters compared to other educational methods. More research is needed to determine if the less-used tools indicated in our survey (social media, Extension website blogs, mailed newsletters, and phone calls or phone-based apps) are favored by professionals who do not regularly attend in-person events. Regardless, updating and creating new resources through multiple avenues that practitioners prefer to use can help increase awareness and use of Extension materials.