International Turfgrass Society Research Journal最新文献

Disease incidence trend of creeping bentgrass (Agrostis stolonifera L.) in Japan was investigated based on diagnosis results during 2013–2022. Anthracnose was identified most frequently, followed by bacterial disease, and then Pythium disease. The number of samples diagnosed as these diseases increased in summer. In addition, basidiomycete diseases and pink snow mold were identified frequently. As dollar spot is easily identified on site, the number of the sample was low. In recent years, due to consistently high temperatures, the number of samples in September has tended to increase. Among bacterial diseases, brown stripe (bacterial decline) was identified most frequently, followed by halo blight and bacterial leaf blight. The incidence of brown stripe has tended to increase.

Saitama Stadium 2002 was built for the 2002 Japan–Korea World Cup. At the 2017 International Turfgrass Research Conference. Tonogi and Wajima presented a report entitled “A 12-year evaluation report of the playing field at Saitama Stadium 2002, which has a floor soil structure with a high sand ratio and an underground temperature regulating structure.” This is the follow-up report summarizing the survey results from 2015 to 2022. The same equipment was used continuously for various measurements, and this study is based on accumulated data. We report on the results of operating the ground-heated piping system in response to annual weather fluctuations.

Since 2016, stem black rot syndrome has occurred on creeping bentgrass (Agrostis stolonifera L.) putting green of 16 golf courses in Japan. Common fungi were isolated from these symptomatic tissues. Phylogenetic analysis of these isolates using the maximum likelihood method based on rDNA-ITS sequence showed >95% homology to Candidacolonium agrostis, which has been reported as a possible pathogen of A. stolonifera in China. Three isolates were inoculated into A. stolonifera, and all isolates showed symptoms of stem rot, and fungi with morphological characteristics similar to those of the inoculated isolates were observed in the diseased areas. The temperature growth response of three isolates was confirmed, with optimal growth temperatures of 30°C or 35°C. These findings suggest that the disease is caused by Candidacolonium sp., but the site of infection and symptoms are somewhat different from those of the disease caused by C. agrostis; further, information such as phylogenetic analysis based on sequencing of multiple regions and morphological characteristics are needed to identify species.

Blue grama [Bouteloua gracilis (Wild. Ex Kunth) Lag. Ex Griffiths] is a low-input residential lawn alternative that is native to North America. However, previous research indicates that weed competition can be a detriment to successful establishment. Therefore, our objective was to evaluate the growth attributes during germination and seedling development of blue grama in response to five herbicides at establishment. An in vitro study was conducted at different osmotic potentials to determine the impact of soil moisture on seed germination and root and shoot development following exposure to herbicides. In a greenhouse study, halosulfuron, imazapic, mesotrione, and metsulfuron were applied to 0- to 12-day-old seedlings. Plant response to herbicides was quantified by leaf height, leaf count, tiller count, visually estimated injury, root weight, shoot weight, and root/shoot ratio. Halosulfuron, metsulfuron, and imazapic were generally safe on blue grama seedlings, while mesotrione caused unacceptable injury, regardless of seedling age. Additionally, herbicides applied immediately after planting did not have a significant effect on seedling germination. Results from these studies provide viable herbicide options to aid in blue grama establishment as a residential lawn grass.

Based on the results of disease diagnoses from 2013 to 2022, trends in the incidence of zoysiagrass diseases in Japan were examined. Zoysia decline, large patch, and necrotic ring spot were the most frequently observed diseases, in that order. These were followed by patch with white leaf and sheath, Pythium blight, Rhizoctonia patch, and dollar spot. Necrotic ring spot, Rhizoctonia patch, Zoysia decline, and circular poor growth of zoysiagrass in spring (CPG) were likely sampled more frequently because these diseases occur at the same time of year and are challenging to identify in the field. In recent years, the number of samples for necrotic ring spot and Zoysia decline has decreased. On the other hand, the number of samples for CPG has not changed. The factors that cause the occurrence of CPG remain unclear, so it will be necessary to study the conditions under which the disease occurs in the future.

Shade poses a significant challenge to the growth and maintenance of turfgrasses, particularly in environments such as urban landscapes and residential lawns. This study aimed to evaluate the shade tolerance of advanced breeding lines of bermudagrasses (Cynodon Rich. spp.), seashore paspalum (Paspalum vaginatum Swartz), St. Augustinegrass [Stenotaphrum secundatum (Walter) Kuntze], and zoysiagrasses (Zoysia Willd. spp.) in field trials from 2021 to 2023 using poly-fiber cloth shade structures at six locations across the southern region of the United States. Turfgrass quality and percent green cover were evaluated under varying levels of shade using a 1–9 visual rating scale and digital image analysis, respectively. Results indicated significant variations in shade tolerance among the breeding lines for all genera. In bermudagrass, OSU2021 consistently exhibited superior turfgrass quality and percent green cover under shade, outperforming traditional check entries such as OKC 1131 (Tahoma 31^®) and Tifway. For seashore paspalum, UGP341 and UGP358 demonstrated enhanced shade tolerance compared to check entries SDX-1 (SeaDwarf™) and TE-13 (Platinum TE^®). In St. Augustinegrass, DALSA1913, DALSA1910, and NCXS12341 maintained higher turfgrass quality and percent green cover under shade than standard cultivars SS-100 (Palmetto^®) and Raleigh. Zoysiagrass breeding lines TifZ20301, TifZ20305, and NCXZ14069 (Lobo™) showed promising shade tolerance, outperforming check entries Diamond and Palisades. These findings suggest that shade tolerance can be significantly improved through turfgrass breeding, offering practical solutions for turf management in shaded environments. These advanced breeding lines identified herein have the potential to enhance turfgrass quality and sustainability, reducing the need for intensive management practices in areas with limited light availability.

Optimum fertilizer rates can be determined by suitable statistical models to yield data collected from N fertilizer experiments. We evaluated logarithmic, quadratic, and square root models describing yield response of zoysiagrass and Kentucky bluegrass to rates of N fertilization. The dry matter yield of zoysiagrass and Kentucky bluegrass were fitted best to the square root (R² = 0.856, p < 0.001) and quadratic (R² = 0.914, p < 0.001) models, respectively, with highly significant determination coefficient. Results of this study suggest that the proper model to interpret the yield of zoysiagrass and Kentucky bluegrass in respect of N fertilizer application can be used as a good indicator in predicting sod production.

This study was conducted to identify genetic diversity and spatial genetic structure in natural populations of zoysiagrasses using inter-simple sequence repeat markers for the purpose of establishing highly efficient measures for preserving zoysiagrass. The genetic diversity indices based on the Nei's gene diversity (H) and Shannon's information index (I) were 0.048 and 0.072 in site I and 0.024 and 0.034 in site II. Compared to site II, site I contained more diverse genotypes per unit area. The analysis of molecular variance showed that 56.2% of the genetic variations were attributed to variations among populations, while 43.8% were attributed to the variation within populations. It was deemed that the high rate of inter-plot genetic variations reflected the species-specific characteristics in reproduction mode. The spatial genetic structures of the zoysiagrasses based on the correlogram analysis indicated that genetically similar individuals were found within 2 m of each other in the Zoysia japonica site I, but genetically different when two genotypes were grown more than 3.5 m apart. On the other hand, there was a random distribution of individuals at all distances, and no distinct genetic colonies were formed in the Zoysia sinica site II. Results from this study demonstrated that for ex situ genetic conservation of zoysiagrasses, the sampling strategy should be considered in intervals of at least 2 m.

The evaluation of turfgrass cultivars is paramount for the turfgrass industry, but it is still based on visual subjective determinations. However, in the last decades aerial or ground reflectance devices are providing very useful objective data that sometimes need a quality analysis, as these devices have been previously programmed in a particular way not always understood by the final user. The objective of this research was to compare the normalized difference vegetation index (NDVI) data provided by two different hand-held devices, a Crop-Circle sensor and a Green-Seeker sensor, over six different bermudagrass cultivars during 1 year. Both tested devices provided different NDVI data when tested over the canopy of the bermudagrass cultivars, but differences were minimal (maximum difference of 0.14 NDVI points) and not significant in terms of NDVI. That difference between devices was due to the different wave length used for the red radiation emission. The NDVI correlation between devices was high, the Pearson correlation coefficient ranged from 0.85 to 0.95, with the higher correlations corresponding to the more dense cultivars Princess 77 and Princess 77 + Sultan.

We report the results of an investigation into the establishment of a stable snow-melting technique for turf management using an underground installed pipe-heated system at the Miyanosawa Shiroi Koibito Soccer pitch in Sapporo, Hokkaido. With appropriate temperature control, we confirmed that the snow accumulation on the field melted, and the roots continued to grow even with snow covering the field. This management system will not only melt snow but can also potentially positively affect turfgrass growth under cold temperatures in early spring.