International Turfgrass Society Research Journal最新文献

Zoysiagrasses (species of Zoysia Willd.) are native in the western Pacific Rim (including eastern Asia) and in the Indian Ocean. All are perennial warm-season grasses. Five species are found naturally in different habitats in Japan: Japanese lawngrass (Zoysia japonica Steud.), manilagrass [Zoysia matrella (L.) Merr.], Zoysia pacifica (Goudswaard) M. Hotta & Kuroki, Zoysia macrostachya Franch. & Sav., and Zoysia sinica Hance. Japan is a high rainfall, mountainous country, predominantly forested but with more limited areas of natural and seminatural grassland (e.g., in drier locations or following clearing) dominated by Imperata cylindrica (L.) Raeusch., Miscanthus sinensis Andersson, and Z. japonica. Such grassland areas have historically been used since the fourth century AD as grazing lands for cattle and horses, although their importance has diminished since 1945. Ornamentally, zoysiagrasses (mainly Z. japonica) were first used as groundcover on tombs more than 1600 years ago, followed by their use in gardens and to stabilize roofs. With the advent of the Samurai warrior class, the formal style of garden with artificial mountains covered by Z. japonica or Z. matrella with ponds became popular for leisure activities, including socializing and entertaining. More widely in agriculture, Z. japonica has had a long history in the production of japonica rice (Oryza sativa subsp. japonica Kato), the staple food in Japan, where it was used to stabilize levee banks around paddy fields. In so many different contexts and applications, zoysiagrasses have strong, wide-ranging, and longstanding historical links to Japanese culture.

A field experiment was conducted to determine the competitiveness of different bentgrass (Agrostis spp.) cultivars established vegetatively into a Poa annua fairway. This experiment was conducted at the Rutgers Horticulture Farm in North Brunswick, NJ, from 2018 to 2023. Treatments consisted of eight bentgrass cultivars. Seven creeping bentgrass (Agrostis stolonifera L.) cultivars were selected to represent a gradient from low density, older cultivars to higher density, modern cultivars and consisted of Penncross, L-93, 007, Shark, Luminary, Piranha, and Flagstick. Puritan colonial bentgrass (Agrostis capillaris L.) was also included. The site was a P. annua fairway maintained at a 9.5 mm mowing height. Bentgrass was established for each plot by cutting four sod strips of a particular cultivar from a nursery and installing them in the P. annua fairway in parallel, spaced 15 cm apart. Treatment differences were most apparent from June 2021 until May 2023 when Shark and Piranha consistently provided the most bentgrass cover. On most dates, bentgrass cover provided by 007 and Luminary, but not Flagstick, was similar to Piranha and Shark. Modern bentgrass cultivars with improved density were more competitive against P. annua in a fairway than older cultivars Penncross and L-93.

Rising salinity levels in both water and soil pose a pressing challenge for golf course managers throughout the United States. To address this issue, turfgrass managers seek effective products to improve plant health and reduce the impacts of salinity stress. The objective of this study was to evaluate the effects of a mineral oil product on salinity stress in bermudagrass [(Cynodon dactylon (L.) Pers. × Cynodon transvaalensis Burtt Davy), cv. Tifway]. The experiment was conducted in a controlled environment in Stillwater, OK, where bermudagrass was established from sprigs and grown in lysimeters filled with sand. The experimental design was a split-plot, with irrigation salinity treatment as the main plot factor and the rate of horticultural mineral oil (Civitas Turf Defense Pre-M1xed; Intelligro) as the sub-plot factor. Irrigation salinity treatments included three electrical conductivity levels: 1.5, 15, and 30 dS m⁻¹, and Civitas was applied every 2 weeks at rates of 0, 1.43, and 2.71 mL m⁻². Over 8 weeks, Tifway bermudagrass was evaluated weekly in terms of turf quality, normalized difference vegetation index, vertical shoot growth, and percent green cover. At the end of the study, salt uptake was assessed by measuring the tissue sodium (Na⁺) concentration and Na⁺ excretion rate from leaf salt glands. Additionally, root biomass was measured. Results showed a decline in turfgrass performance and an increase in tissue Na⁺ concentration as salinity levels increased. Tifway maintained good quality at 15 dS m⁻¹ for 8 weeks in sand, both without Civitas and with an application rate of 1.43 mL m⁻². However, increasing the application to 2.71 mL m⁻² consistently compromised turfgrass performance under 30 dS m⁻¹ salinity stress, highlighting its adverse effects in highly saline conditions.

Consumer demand for certified-organic weed control in turfgrass has grown, yet information on nonsynthetic herbicide performance, safety, and environmental impacts is limited. This study evaluated several acid- and oil-based chemicals and synthetic comparisons for winter weed control in dormant bermudagrass [Cynodon dactylon × C. transvaalensis (Pers. L.) ‘Latitude 36’] and zoysiagrass [Zoysia matrella (L.) Merr. ‘Cavalier’]. Four nonsynthetic herbicides (ammonium nonanoate, acetic acid, citric acid + clove oil, and d-limonene) applied twice or thrice were compared to glufosinate and glyphosate applied once. Acetic acid was also tested at three concentrations (20%, 30%, 40%) when applied thrice. Results showed that acetic acid consistently controlled corn speedwell (Veronica arvensis L.) and common chickweed [Stellaria media (L.) Vill] as well as glufosinate and glyphosate, but annual bluegrass (Poa annua L.) control by acetic acid was concentration- and application frequency-dependent. Other nonsynthetic chemicals did not acceptably control any of the weeds evaluated at 91 days after treatment. Acetic acid applied thrice controlled annual bluegrass similar to glufosinate and glyphosate. However, lower concentrations of acetic acid were less effective against mature annual bluegrass. The study highlights the potential of acetic acid as an organic herbicide for weed control in turfgrass, especially for broadleaf weeds. However, organic chemicals cost 240–2370 times more than glyphosate and deliver 132–1596 times more active ingredient into the environment. Further research on optimizing application strategies is warranted to enhance weed control efficacy, equitable access, and environmental sustainability of organic weed control in turfgrass systems.

Ice encasement (IE) is one of the big challenges in winter stress management on golf course putting greens in Northern Scandinavia. The turfgrass is damaged due to lack of oxygen (hypoxia or anoxia) and accumulation of toxic by-products of anaerobic respiration. Breeding IE-tolerant turfgrass species and varieties is the best defense against these challenges. A method to simulate ice encasement was tested to screen selected varieties of winter-hardy bentgrass species and red fescue subspecies. Note that 32 varieties were chosen from the SCANGREEN trial seeded at NIBIO Landvik, Norway, in 2019. Samples were taken in December 2020, 2021, and 2022, vacuum sealed in plastic, and stored in darkness at 0.5°C for up to 77 days to test them for their tolerance to simulated ice encasement (SIE). Samples were incubated at different intervals; plants were potted, and tiller survival was tested after 4 weeks of regrowth. Lethal duration of ice encasement (LD₅₀) that is, the number of days under anoxia that kills 50% of the plant population for each species and variety was calculated. The results showed that the ranking of cool season turfgrass species for tolerance to SIE was velvet bentgrass > Chewings fescue > slender creeping red fescue = colonial bentgrass > creeping bentgrass. This ranking does not fully reflect the ranking found in field tests where velvet bentgrass was superior together with creeping bentgrass. SIE caused a more rapid development of anoxia than IE in the field, and we hypothesize that creeping bentgrass is less tolerant to these conditions compared to the other species tested. To make the SIE method more representative for IE in field, it should be further adapted with incubation at lower temperatures, and with acclimation conditions to be standardized prior to sampling. Within species, the best tolerance to IE was found in velvet bentgrass Nordlys, creeping bentgrass Penncross, Chewings fescue Lykke, and slender creeping red fescue Cezanne.

The increase in golfing rounds since 2020 has led to more acute putting surface disruption (PSD) on golf course playing surfaces. Specifically, the concentrated PSD at the hole location is a concern for the game of golf and playing surface management. This study was designed to investigate the contribution of variables such as golf footwear tread type, walker, putting surface characteristics, and prevailing weather conditions on PSD, as measured by visual traffic damage and ball roll distance, near a simulated hole location. A random forest machine learning approach was applied to a dataset of 19 golf footwear trials conducted at the Cornell University Turfgrass and Landscape Research Center in Ithaca from 2019 to 2023. Results indicate that visual traffic damage could be only moderately predicted (R² = 0.48), with the most important factors being the individual walker and tread type, whereas ball roll distance was unable to be reliably predicted (R² = 0.16). These findings highlight the need for further investigation into variables that could better inform maintenance strategies that mitigate PSD and, thus, improve the golfer experience.

Anthracnose, caused by Colletotrichum spp., is a severe and devastating disease in turfgrasses. While mycoviruses have been identified in several Colletotrichum isolates from turfgrasses, their effects on host fungal phenotypes remain unclear. This study investigated the impact of Colletotrichum associated partitivirus 1 (CaPV1) infection on Colletotrichum zoysiae isolate MBCT-264 from Zoysia matrella. CaPV1-infected and virus-free C. zoysiae isogenic strains were established through five successive passages on potato dextrose agar (PDA) with or without a virus polymerase inhibitor. Comparative growth analysis on PDA revealed slower growth of the CaPV1-infected strain compared to the virus-free strain. Inoculation tests on Z. matrella leaf blades demonstrated that the CaPV1-free strain produced larger lesions and more pronounced mycelium penetration than the virus-infected strain. These findings suggest that CaPV1 infection negatively affects both the growth and virulence of C. zoysiae, highlighting the potential of mycoviruses in modulating turfgrass pathogen behavior.

A field study was conducted in Athens, GA, to evaluate JSC 2-21-18 (Iron Cutter^®) hybrid bermudagrass (Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt Davy) response to postemergence herbicides (topramezone + metribuzin, thiencarbazone-methyl + foramsulfuron + halosulfuron, thiencarbazone-methyl + iodosulfuron + dicamba, 2,4-D + triclopyr + dicamba + pyraflufen, foramsulfuron, sulfosulfuron, monosodium methanearsonate, quinclorac, and 2,4-D + mecoprop + dicamba + carfentrazone). Thiencarbazone-methyl + foramsulfuron + halosulfuron, thiencarbazone-methyl + iodosulfuron + dicamba, monosodium methanearsonate, and 2,4-D + mecoprop + dicamba + carfentrazone resulted in similar turfgrass color (TC), turfgrass quality (TQ), and normalized difference vegetation index (NDVI) as the non-treated check, regardless of rating date. Topramezone + metribuzin and 2,4-D + triclopyr + dicamba + pyraflufen were most injurious, causing significantly lower TC, TQ, and NDVI than the non-treated check 3 weeks after treatment (WAT). Decreases in TC were also observed in response to quinclorac, sulfosulfuron, and foramsulfuron 3 WAT; however, recovery from quinclorac and sulfosulfuron was reported 4 WAT. A second study examined JSC 2-21-18 response to trinexapac-ethyl (TE), prohexadione calcium (PC), and TE + PC applied every 2 weeks. All treatments resulted in higher TC, TQ, and NDVI than the non-treated check 40 days after initial treatment (DAIT), except TE at 96 g ai ha⁻¹ with respect to TQ. The highest TC, TQ, and NDVI was observed in response to PC at 460 g ai ha⁻¹. At 84 DAIT, TE + PC resulted in the greatest percent growth inhibition (GI) (46%) followed by PC (41%), regardless of rate, while TE only resulted in % GI of 31%–32%. In general, a greater increase in aesthetics and inhibition was observed in response to PC than TE.

Several studies have demonstrated the water conservation potential of soil moisture sensor-based irrigation scheduling on turfgrass areas; however, research is lacking on the accuracy of satellite-based moisture measurements. A field study was conducted in 2023 to investigate the accuracy of moisture values based on electromagnetic pulses emitted from the synthetic aperture radar mounted on Sentinel-1A. The estimates based on satellite remote sensing were compared to measurements collected on fairways 2 and 7 of Sunset Golf Course (Las Campanas, NM) by a ground-penetrating capacitance sensor (Toro Precision Sense 6000 [PS 6000]) during June and July 2023. The relationship between values estimated using Sentinel-1A and readings from PS 6000 was significant but weak (R² ranging from 0.01 to 0.045) on fairway 2 on all sampling dates. On fairway 7, the association was significant only on two of four sampling dates, reaching R² values of 0.015 and 0.021. The relationship was significantly negative (slope −0.37; R² = 0.037) for fairway 2 on one sampling date. Generally, the satellite-derived soil moisture data underestimated soil moisture variability when compared to PS 6000 measurements and indicated a greater moisture uniformity than actually present. Results of our study indicate that Sentinel-1A satellite data appear to be impractical for the purpose of determining soil moisture in turfgrass areas. More studies are needed to improve the accuracy of measurements and to determine if different mathematical models should be used to estimate soil moisture based on reflectance values on turf areas.

The Clegg impact soil tester (CIST) and TruFirm Turf Firmness Meter (TruFirm) are devices that measure turf surface hardness. Correlations between the devices have been limited to putting greens with little attention paid to higher mowed athletic fields. The objectives of this study were to determine the ability to predict CIST values from TruFirm measurements, with and without considering soil volumetric water content (VWC), and to evaluate how traffic influences the predictive relationship between the devices. TruFirm, CIST, VWC, and Normalized Difference Vegetation Index (NDVI) measurements were obtained from bermudagrass [Cynodon dactylon (L.) Pers × Cynodon transvaalensis Burtt Davy] research plots with and without the use of a Baldtree traffic simulator to apply traffic and from bermudagrass soccer fields receiving heavy play in 2 of the 3 years the study was conducted. Cultivation practices were imposed across all sites with the turfgrass overseeded with intermediate ryegrass (Lolium × hybridum Hausskn.) in October each year. Poor fits were obtained from trafficked research plots (r² = 0.26, p < 0.0001) and athletic fields (r² = 0.19, p < 0.0001) when predicting CIST from TruFirm measurements. Adding VWC as a second variable raised the coefficient of determination in trafficked research plots (R² = 0.46, p < 0.0001) and athletic fields (R² = 0.41, p < 0.0001), with both relationships continuing to have a high degree of uncertainty in predicting CIST. NDVI was significantly higher for the trafficked research plots than for the non-trafficked research plots and athletic fields. On the non-trafficked research plots, the simple linear relationship between CIST and TruFirm was not significant (p = 0.1782), which may be due to CIST and TruFirm having differential responses to changes in turf canopy properties. This may be due to the shape and mass of the objects used to measure hardness and firmness in the two devices.