Tall fescue ( Festuca arundinacea Schreb.) is a cool-season turfgrass species commonly used in the transition zone. Brown patch ( Rhizoctonia solani Kuhn) can have a significant impact on quality of tall fescue between late spring and late summer and is impacted by management strategies including fertilization and fungicide use. The objective of this study was to evaluate the influence of four nitrogen (N) sources and two application rates (0, 74 kg ha −1 [low], or 220 kg ha −1 [high] annually) along with fungicide application (azoxystrobin applied or not applied) on tall fescue brown patch infection. Highest quality occurred when tall fescue received the highest level of N and fungicide treatment. If high levels of N were applied and no fungicide was used, quality was reduced significantly when brown patch was observed in tall fescue. For example, on July 21, 2023, when most intense brown patch occurred, tall fescue had variable brown patch levels: low N levels 2%–23% and high N levels 48%–66%. Across three rating dates in summer 2023, tall fescue receiving the low N level exhibited statistically similar brown patch among all N sources. Conversely, brown patch treated with high levels of N had lower brown patch in urea compared to humic-coated urea and slow-release N on at least one of the three dates. Applying N at a level of 220 kg ha −1 annually or higher can result in significant brown patch in some summers; lower N levels will reduce brown patch. Desiring high tall fescue quality requires the high N level and inclusion of preventive fungicide applications.

Zoysiagrass (Zoysia spp. Willd.) is a desirable, low-input turfgrass species used on golf courses. However, prolific zoysiagrass seedhead production in the spring can increase golf course maintenance costs and reduce aesthetics. Previous research demonstrates that a single autumn ethephon application can suppress zoysiagrass seedhead production the following spring, but the optimum application timing is not well-defined. The objective of this research was to determine the optimum window for an effective ethephon application for 'Meyer' zoysiagrass seedhead suppression. Small-plot field research was conducted in Indiana, Kansas, Arkansas, and Tennessee. Seedheads were suppressed up to 99% depending on application timing. In Indiana, applications made on September 19 provided 99% seedhead suppression. In Kansas, applications between August 30 and September 18 yielded >64% seedhead suppression. In Arkansas, applications between October 3 and October 17 yielded >52% seedhead suppression. In Tennessee, applications between September 19 and October 23 provided >78% seedhead suppression. Applications made outside these windows resulted in more seedhead production at each respective location. Interestingly, optimum application timing was approximately 2 weeks later in Arkansas and Tennessee compared to Indiana and Kansas. Using growing degree days, a nonlinear Gaussian model was fit to predict the optimum ethephon application timing. In addition to data from this research, the proposed model accurately predicted observed zoysiagrass seedhead suppression in previously published research. This research better characterizes the optimum autumn application timing for Meyer zoysiagrass seedhead suppression across the transition zone.

Irrigation methods that can minimize water use are needed, and the performance of recently released ‘KSUZ 0802’ hybrid zoysiagrass (Zoysia matrella × Zoysia japonica) has not been evaluated under such management. Therefore, field experiments were conducted in Manhattan, KS, and Dallas, TX, USA, to compare the amount of water applied and ‘KSUZ 0802’ performance and recovery resulting from irrigation using the following: 1) routine irrigation (1.2 inches/week), 2) evapotranspiration (ET)-based irrigation (60% of reference ET), 3) soil moisture sensor (SMS)-based irrigation, and 4) no irrigation. The experiment was conducted under a rainout shelter in Kansas from 15 Jul to 27 Sep 2019 and 8 Jun to 19 Oct 2020, and in Texas the experiment was conducted under open field conditions from 22 Jun to 9 Sep 2020. The SMS-based irrigation method in Kansas reduced water application by 68% and 52%, respectively, compared with routine or ET-based irrigation. In Texas, the corresponding water savings were 29% and 13%, respectively. The water savings discrepancy was mainly due to differences in local weather conditions and irrigation demand. Visual turf quality of turf receiving SMS-based irrigation remained above the minimally acceptable level throughout the study in Kansas, whereas in Texas, turf quality declined below acceptable level after 2 weeks. In Kansas, turf retained acceptable quality for more than 21 days with no irrigation, and after rewatering, nonirrigated turf recovered back to significant green cover (93% in 2019 and 67% in 2020). ‘KSUZ 0802’ demonstrated good drought tolerance and recovery in Kansas.

‘DALZ 1701’ (Reg no. CV‐292, PI 702798) is a third‐generation hybrid resulting from mating interspecific hybrid ‘TAES 5723‐47’ with Zoysia japonica (Steud.) ‘ Meyer’. In the 2019 National Evaluation Turfgrass Program, which ran from 2019 to 2022 in 15 locations, DALZ 1701 was put to the test. In 9 of 13 locations, DALZ 1701 established more quickly than Meyer, similarly to Emerald and Zeon but slower than Empire. DALZ 1701's turfgrass quality was generally better than Meyer's and on par with that of Emerald, Empire, and Zeon. Compared with Meyer, DALZ 1701 displays a dark green genetic color. In Dallas, TX, DALZ 1701 maintained its quality under drought stress more effectively than Meyer and similarly to Emerald, Empire, and Zeon; however, it had more wilt avoidance than Emerald and Zeon. Like Meyer and Innovation, DALZ 1701 showed freezing tolerance but had improved fall color retention. DALZ 1701 appeared to have greater tolerance than Meyer to large patch ( Rhizoctonia solani Kühn), spring yellowing [take‐all patch ( Gaeumannomyces graminis (Sacc.) von Arx & D. Olivier)], hunting billbug ( Sphenophorus venatus vestitus Chittenden), and zoysiagrass mite ( Eriophyes zoysiae Baker, Kono, and O'Neill) damage. Additionally, DALZ 1701 has shown quality comparable to Diamond and Palisades but superior to Meyer under moderate shade in Dallas, TX. In the transition zone and southern portions of the United States, where zoysiagrass is widely grown, DALZ 1701 is adaptable to a variety of conditions.

'KSUZ 0802' zoysiagrass (Innovation zoysiagrass, Zoysia matrella x Z. japonica) is a new cultivar that provides a high-quality playing surface on golf course fairways and tees. However, seedheads produced in late spring disrupt the playing surface. The plant growth regulator (PGR) ethephon has produced variable results in prior studies in suppressing zoysiagrass seedheads, and information for KSUZ 0802 is lacking. A two-year field experiment was conducted from 2019-2021 in Manhattan, KS, to assess the performance of ethephon (Proxy) on seedhead suppression of KSUZ 0802 zoysiagrass. Treatments included ethephon applied in a single application at 5 fl. oz. 1000 ft(-2) on multiple dates between August and November. Seedhead suppression was determined by counting seedheads in late spring. Ethephon applied in September provided >60% seedhead suppression; however, when applied during other months, variations were large between the two study years. Applying ethephon when accumulated cooling degree days (68 degrees F base) were <37 resulted in >70% seedhead suppression, except for application on September 25, 2019. Late August ethephon applications, despite achieving good seedhead suppression (ranging from 54 to 80%), caused transient yet commercially unacceptable injury to KSUZ 0802 in both years. Application timing affected turf quality in late spring as KSUZ 0802 with fewer seedheads had better quality post-mowing, but no effect on spring greenup was observed. Ethephon can be an effective PGR for seedhead suppression in KSUZ 0802 zoysiagrass. However, careful consideration of application timing is essential as applying ethephon in late summer or late autumn can produce undesirable results.

Shade and drought commonly occur together in turfgrass systems due to competition with trees for light and soil water. Two greenhouse studies were conducted to evaluate the effects of combined drought and shade stress on bermudagrass [ Cynodon dactylon (L.) Pers.] and hybrid bermudagrass [ C . dactylon (L.) Pers. × C . transvaalensis Burtt Davy] physiology. ‘Latitude 36 Turf Bermudagrass’ (Latitude 36 TM ) hybrid bermudagrass and ‘Riley's Super Sport’ (Celebration ® ) bermudagrass were selected for Experiment 1, while ‘Patriot’ hybrid bermudagrass was added as a shade-sensitive cultivar in Experiment 2. Washed plugs of each cultivar were planted in growth tubes (10 cm diameter by 46 cm length polyvinyl chloride pipe with a flat bottom cap) filled with a 1:1 topsoil/sand root-zone. Each experiment was conducted as a completely random design with two factors (cultivar and irrigation) repeated under two light environments. Light environment was defined as either adequate light (20.8–26.8 mol m –2 d –1 ) or low light (9.7–10.1 mol m –2 d –1 ) conditions. Irrigation was applied by hand to achieve either 100% (well-watered) or 50% (drought) replacement of evapotranspiration (ET). Under drought conditions, low light resulted in a gradual decline in ET rate, whereas adequate light showed a sharp decline in ET rate over time. Under adequate light, Patriot consumed the most water among cultivars for either well-watered or drought conditions. In contrast, Patriot (well-watered) had the lowest water use in the low light environment, suggesting shade tolerance could potentially influence drought response under low light environments.

Late summer and autumn application of nitrogen (N) to bermudagrass ( Cynodon spp.) in the transition zone has been associated with enhanced turfgrass color but has been thought to increase the potential for winter injury. Eleven N sources were applied in late summer and early autumn to provide a total annual N level of 98 kg ha −1 in Olathe, KS to evaluate fall color and spring green coverage of ‘Riviera’ bermudagrass [ Cynodon dactylon (L.) Pers.]. Treatments included experimental coated urea fertilizers, N sources containing urease inhibitors, urea, and nontreated turfgrass. Significant winter injury occurred throughout the experimental area. Turfgrass color in late October was positively correlated with green coverage evaluated in May ( r  = .55; P  < .001). For example, bermudagrass treated with AND3.0EX (Poly/Humic Coated Urea) had a color rating of 3.5 (1 to 9 scale; 9 = dark green) in late October, and green coverage in May was 44%. Nontreated turfgrass had a color rating of 1.5 in late October, and green coverage in May was 8%. Enhanced winter survival of bermudagrass following late-season N application may require that turfgrass managers rethink traditional N programs limiting application to only late spring and midsummer dates in the transition zone.

A 10-yr, four-phase collaborative effort among three universities was conducted to develop new hybrid zoysiagrasses (Zoysia spp. Willd.) with improved turf quality, winter hardiness, and pest resistance in comparison to commercial zoysiagrass cultivars, especially 'Meyer' (Z. japonica Steud.). In Phase 1, breeding efforts produced 2,858 new progeny that were evaluated for 2 yr across three sites. In Phase 2, only 60 (2%) of 2,858 progeny were selected for advancement to 10 replicated multiyear field trials (Phase 3). Phase 3 revealed 10 promising progeny (assigned DALZ numbers) that required further intensive field and laboratory testing in Phase 4. Phase 4 revealed differences in establishment rate, and DALZ 1701, 1702, 1707, and 1810 had moderate-to-good turf performance across seven sites, whereas DALZ 1808 had similar or slightly lower performance. Meyer consistently performed poorly, and 'Innovation', a recently released hybrid cultivar, had poor-to-moderate performance in comparison to the experimental genotypes, which illustrates the improvements achieved in zoysiagrass breeding in the last 10 yr. Freeze tolerance (LT50, lethal temperature killing 50% of the plants) ranged from -9.8 degrees C (Diamond) to -14.1 degrees C (DALZ 1812) with a mean of -12.5 degrees C. Evidence of large patch [Rhizoctonia solani Kuhn, anastomosis Group (AG) 2-2 LP] in the top 10 DALZ genotypes was 15 to 40% lower than Meyer on several dates. Results indicate that there are multiple genotypes for potential release in the future with improved turf color, winter hardiness, freeze tolerance, large patch resistance, and finer leaf texture suitable for USDA plant hardiness zones ranging between 5b and 8a.

A set of 70 experimental zoysiagrass genotypes along with three standards, ‘Meyer,' ‘Innovation,' and ‘KSUZ 1201,' were evaluated for turf performance in the northern transition zone. The genotypes were previously selected from a set of 935 progeny that resulted from pairwise crossings of cold-hardy zoysiagrass parents with fine-textured, under-utilized zoysiagrasses. All 70 progeny survived the winter of 2019–2020 and thus were evaluated based on their turf performance. The preference of selection was based first upon spring green up ratings, followed by leaf texture (finer preferred), vigor, turf quality, and wilt during dry down. A total of 20 best progeny were selected and harvested for propagation on October 12, 2020. Only one genotype, ‘6844-31’ had a texture rating of 8.0 (1 to 9 scale; 9 = finest texture) and four other genotypes had texture ratings higher than 7.0 among the selected 20 best progeny. The progeny will be established in larger replicated plots at several locations including Kansas State University Olathe Horticulture Center, Olathe, KS, starting in the summer of 2021

Objective methods of estimating green coverage using digital image analysis have been used increasingly by turfgrass scientists. The objective of our research was to evaluate the effectiveness of Canopeo, a relatively new smartphone application, for estimating green coverage of bermudagrass (Cynodon dactylon) emerging from winter dormancy, with or without colorants. A field study was conducted on a research ‘U3’ bermudagrass fairway in Stillwater, OK, during Spring 2019 and 2020. The experiment was conducted as a randomized complete block design with three colorant treatments: Endurant Fairway (FW), Endurant Perennial Ryegrass (PR), and an untreated control. Green coverage of the turfgrass canopy was determined weekly from mid-March to early May using a digital camera and ImageJ software, and a smartphone and the Canopeo application. Green coverage estimates from Canopeo correlated strongly (r = 0.91) with those from ImageJ when no colorants were applied. Correlation between Canopeo and ImageJ was diminished under plots treated with colorants. Canopeo is an effective tool for estimating green coverage of living turfgrasses, but additional calibration may be required for acceptable performance when evaluating greenness of colorant-treated turfgrasses.

The National Turfgrass Evaluation Program (NTEP) Zoysia Test was planted in 2019 at the Kansas State University Olathe Horticulture Center, Olathe, KS. Since planting, three experimental genotypes developed at K-State (with cooperators noted below) have outperformed ‘Meyer’ in establishment rate, turf quality, drought tolerance, and fall color. Earlier research has demonstrated large patch tolerance in all three experimental genotypes.

Abstract The performance of ethephon (Proxy) on seedhead suppression of ‘Innovation’ zoysiagrass was evaluated during the 2019–2020 growing season in Manhattan, KS. Treatments evaluated Proxy applied in a single autumn application at 5 fl. oz./1,000 ft 2 on multiple dates between August 28 and November 26, 2019. Seedhead suppression ranged from 15% (application on November 1) to 82% (applied on September 4). Dates between September 4 and October 3 were the optimum application window for ethephon application on Innovation zoysiagrass as seedhead suppression was at least 62% with minimal turf injury occurring. Summary The performance of ethephon (Proxy) on seedhead suppression of ‘Innovation’ zoysiagrass was evaluated during the 2019–2020 growing season in Manhattan, KS. Treatments evaluated Proxy applied in a single autumn application at 5 fl. oz./1,000 ft 2 on multiple dates between August 28 and November 26, 2019. Seedhead suppression ranged from 15% (application on November 1) to 82% (applied on September 4). Dates between September 4 and October 3 were the optimum application window for ethephon application on Innovation zoysiagrass as seedhead suppression was at least 62% with minimal turf injury occurring. golf

Summary Performance of ‘Innovation’ zoysiagrass was evaluated under four irrigation regimes: a) routine irrigation (1.2 inches weekly); b) evapotranspiration (ET)-based irrigation (60% of estimated ET); c) soil water sensor (SWS)-based irrigation; and d) no irrigation. The SWS-based irrigation method reduced water application by 72% and 56%, respectively, compared to routine or ET-based irrigation. Visual turf quality of turf receiving SWS-based irrigation remained above the minimal acceptable level throughout the study. Innovation zoysiagrass sustained acceptable quality for more than 21 days with no irrigation, and nonirrigated turf recovered fully within four weeks after irrigation treatments ceased and turf was well irrigated. Soil water sensors are useful for saving irrigation water, and Innovation zoysiagrass demonstrated good drought tolerance and recovery after drought.

Turf quality characteristics and large patch incidence of ten selected experimental zoysiagrass genotypes were evaluated during the 2018–2019 growing season in Manhattan, KS, and establishment rate of the same ten was evaluated in Olathe, KS. Although plots were inoculated with Rhizoctonia solani (AG 2-2 LP) in September 2018 in Manhattan, no large patch occurred. However, the genotypes showed vari­ability in turf performance measured by turf quality, spring greenup, fall color reten­tion, and genetic color. In Olathe, KS, at Shadow Glen Golf Club, the ten genotypes were planted on June 17, 2019. The range in visual ground coverage on September 27, 2019, was 63.3 to 92.7%.

Since the summer of 2017, 1,376 experimental zoysiagrass genotypes have been evaluated for winter survival in Olathe, KS, in an attempt to identify high quality, fine-textured types that survive in Kansas.After planting 458 progeny in the field in August 2017, only 17 experimental progeny survived when evaluated in spring 2018 (4%).In 2018, those 17 survivors were included with a new planting of 918 experimental progeny.In spring 2019, it was determined that 70 genotypes survived (8%).The 70 surviving progeny were transferred to a new, adjacent plot area in June 2019 and they varied in leaf texture (3.0 to 7.5 on a 1 to 9 scale; 9 = finest) and vigor (2.0 to 8.0 on a 1 to 9 scale; 9 = most vigorous) when visually rated on September 27, 2019.In 2020, all 70 progeny survived and showed variation in spring greenup in April (1.0 to 5.0; 1 to 9 scale, 9 = completely green).By early summer of 2020, best performing progeny with superior cold-hardiness and quality will be propagated for evaluation in larger plots starting in 2021.

Bermudagrass (Cynodon spp.) demonstrates several desirable attributes that contribute to its widespread popularity for use as a turfgrass. However, a significant limitation to more widespread usage is the poor shade tolerance of bermudagrass relative to other species (e.g., Zoysia spp.). Improvement of this trait through recurrent selection of seeded-type cultivars may contribute to increasing the adaptive range of this relatively important turfgrass. A three-year field study was conducted to evaluate the relative shade tolerance of ten commercially-available or experimental bermudagrass cultivars, including seeded-type and clonally-propagated genotypes, in Stillwater, OK. Plots were established in three blocks representing three light environments: full sun, moderate shade (40% of full sun), or severe shade (20% of full sun). Bermudagrass cultivars were evaluated for visual turf quality, normalized difference vegetation index (NDVI), visual spring green-up, and visual plant density. A turf performance index (TPI) was used to develop a relative ranking of shade tolerance among cultivars tested, and a minimum daily light integral (DLI) for each cultivar was calculated using visual turf density as the criterion. Results indicate 'Celebration' was the most shade tolerant cultivar requiring 13 mol m(-2) d(-1) photosynthetically active radiation (PAR) from June through September, while 'Patriot' was the least shade tolerant cultivar requiring 26 mol m(-2) d(-1) PAR. Other cultivars were intermediate in shade tolerance having a minimum DLI ranging from 17 to 21 mol m(-2) d(-1 )PAR. Shade tolerance of experimental cultivars was similar to existing commercially-available cultivars suggesting further selection or breeding effort is required to improve this trait.