Jack D. Fry

A Guide to Establishing Seeded Bermudagrass in the Transition Zone

Aaron J. Patton, Assistant Professor, Mike D. Richardson, Professor, and Doug E. Karcher, Associate Professor, Department of Horticulture, University of Arkansas, Fayetteville 72701; John W. Boyd, Professor, Crop, Soil & Environmental Science, University of Arkansas Cooperative Extension Service, Little Rock 72203; Zachary J. Reicher, Professor, Department of Agronomy, Purdue University, West Lafayette, IN 47907; Jack D. Fry, Professor, Department of Horticulture, Forestry, and Recreation Resources, Kansas State University, Manhattan, KS 66506; J. Scott McElroy, Assistant Professor, Department of Agronomy and Soils, Auburn University, Auburn, AL 36849; and Gregg C. Munshaw, Assistant Professor, Mississippi State University, Department of Plant and Soil Sciences, Mississippi State 39762

Performance in the Transition Zone of Two Hybrid Bluegrasses Compared with Kentucky Bluegrass and Tall Fescue

Hybrid bluegrasses (HBG) are crosses between Kentucky bluegrass (Poa pratensis L.) (KBG) and Texas bluegrass (Poa arachnifera Torr.), which may exhibit better heat tolerance and drought resistance than other cool-season turfgrasses. Two HBG cultivars (‘Thermal Blue’ [HBG1] and ‘Dura Blue’ [HBG2]), one KBG (‘Apollo’), and one tall fescue (Festuca arundinacea Schreb.; ‘Dynasty’ [TF]) were evaluated for two years in northeastern Kansas for establishment rates after seeding, visual quality and growth characteristics, and drought resistance. Irrigation treatments included 60% and 100% evapotranspiration (ET) replacement and a control receiving only natural precipitation. Tall fescue reached full cover 37, 52, and >73 days faster than HBG1, KBG, and HBG2, respectively. In both years, average quality over the growing season ranked: TF > KBG > HBG1 > HBG2; an infestation of bluegrass billbugs (Sphenophorus parvulus Gyllenhal) in 2003 reduced quality among bluegrasses but not TF. Canopy density was lower in HBG2 and higher in TF among treatments. Clipping biomass of TF was 42 to 73% higher than that of the bluegrasses. Vertical growth rates were highest in HBG1 and TF and lowest in KBG. Drought generally reduced quality among bluegrasses, but effects on TF were negligible. Results indicate that TF is better adapted than HBG where soils are deep in the transition zone. Further research is needed using new cultivars of HBG and in areas with different soils.

Development of brown patch and Pythium blight in tall fescue as affected by irrigation frequency, clipping removal, and fungicide application

We studied the effects of irrigation frequency, clipping removal, and fungicide application on the development of Rhizoctonia brown patch (Rhizoctonia solani) and Pythium blight (Pythium aphanidermatum) in tall fescue. Brown patch severity was not significantly different between plots irrigated daily and those irrigated on alternate days. Similarly, no differences in brown patch were observed in plots where grass clippings were returned to the sward with a mulching mower compared with plots where clippings were removed. Preventive applications of azox-ystrobin at 35-day intervals or postinfection applications of chlorothalonil reduced brown patch severity, but only the azoxystrobin treatment provided aesthetically acceptable (<10%) levels of brown patch control. However, azoxystrobin applications also increased Pythium blight compared with untreated or chlorothalonil-treated tall fescue, especially in plots that received daily irrigation.

Quantifying the Effects of Lance Nematode Parasitism in Creeping Bentgrass

We compared photosynthesis and multispectral radiometry (MSR) measurements with visual quality ratings for assessment of feeding injury to creeping bentgrass caused by the lance nematode (Hoplolaimus galeatus) using artificially infested microplots and a naturally infested putting green. Nematode feeding resulted in negative visual and MSR effects on creeping bentgrass in microplots. Visual quality ratings were correlated more consistently with nematode densities than either individual MSR variables or factor models of MSR variables. Threshold estimates for H. galeatus population densities associated with unacceptable bentgrass quality in microplots varied widely by month and year. Similarly, the relationship between H. galeatus population density and turf health indicators (including MSR measurements, visual ratings, and net photosynthetic rate) varied with cultivar and management practice (irrigation frequency and mowing height) in the naturally infested putting green. Notably, negative effects of nematode feeding were not consistently associated with more stressful management practices, suggesting that stress avoidance is not a reliable deterrent to H. galeatus damage in creeping bentgrass. Damage thresholds for this nematode-host association are dynamic and should be used with caution.

Population dynamics of the lance nematode (Hoplolaimus galeatus) in creeping bentgrass

The effects of management practices and nematode population density on the seasonal fluctuationsin lance nematode (Hoplolaimus galeatus) populations in creeping bentgrass were studiedin a naturally infested experimental putting green and in artificially infested microplots. In general, H. galeatus populations increased from late spring through midsummer, declined in August, and increased again in the fall. Population increase in microplots was strongly density dependent, with final population densities inversely proportional to inoculum levels. Ectoparasitic populationsof H. galeatus in both studies were composed of adults and juveniles, whereas endoparasiticpopulations were almost exclusively juveniles. H. galeatus populations in the naturallyinfested site were aggregated spatially, but the aggregation was not temporally stable. Nematodepopulations were not affected by bentgrass cultivar selection or irrigation frequency.

Recovery growth of Meyer and experimental zoysiagrass progeny after sod harvest.

Information is limited on the recovery growth of zoysiagrass (Zoysia spp. Willd.) after sod harvest. ‘Meyer’ and DALZ 0102 (both Z. japonica Steud.) and eighteen zoysiagrass progeny originating from crosses between a Z. matrella (L.) Merr. × Z. japonica or ‘Emerald’ (Z. matrella × Z. pacifica Goudsw.) × Z. japonica were evaluated for sod recovery growth after harvest in Manhattan in 2008 and 2009, and in Olathe, KS, in 2009 and 2010. Sod pieces (51 cm wide × 102 cm long × 5 cm thick) were harvested on 9 July 2008 at Manhattan and on 8 July 2009 at Olathe using a mechanical sod cutter. Sod recovery growth in areas of harvested strips was determined by taking an overhead digital image of a 40- by 35-cm area to determine percentage green coverage. At 60 days after harvest in Manhattan, coverage ranged from 17% to 97%; a progeny from Z. matrella × Meyer (97% coverage) demonstrated superior recovery growth to Meyer (38% coverage). Recovery growth was slower in Olathe where irrigation was applied less frequently, and all progeny were similar to Meyer until 15 July of the summer following harvest, when individual progeny from ‘Cavalier’ × Chinese Common and Emerald × Meyer were superior to Meyer. The potential for faster recovery after harvest compared to Meyer may be attractive to sod producers seeking to maximize the number of harvests from a zoysiagrass sward.

MOWER EFFECTS ON TURFGRASS QUALITY

The type of mower used can affect turfgrass quality. Mowing can affect height uniformity and can cause tip shredding and/or browning of the turf. The mowing performances of rotary and flail mowers were compared on 11 warmseason turfgrasses. Standard Y-shaped blades and experimental T-shaped blades were used on the flail mower. Turfgrass quality at a 33-mm cutting height was better with the flail mower than with the rotary mower. No improvement in turf quality was seen with experimental T-shaped blades compared with Y-shaped blades. The best turfgrass quality obtained at a 33-mm cut was only marginal for a home lawn and inadequate for high-maintenance turf such as golf greens or even fairways. Turfgrass quality at a 76-mm cutting height was superior with the rotary mower. The quality was improved significantly at the higher cut with the rotary mower, but the flail mower yielded the same quality of cut at either height. Leaf tearing at 76 mm was worse with T-shaped flail blades and least with the rotary mower.

Brown Patch Occurrence in a Zoysiagrass-Tall Fescue Polystand Compared to a Tall Fescue Monostand

Research has demonstrated that polystands of zoysiagrass and tall fescue can be established successfully, with the potential to provide a high quality turfgrass stand with reduced inputs. Our objective was to determine whether mixing zoysiagrass with tall fescue will reduce brown patch severity while maintaining overall acceptable quality. Studies were established at the Rocky Ford Turfgrass Research Center in Manhattan, KS. In the split-plot design, natural infection by Rhizoctonia solani or a fungicidetreated control was the whole plot treatment factor and species (tall fescue monostand and the zoysiagrass/tall fescue mixture) were subplots. During July and August 2016 and 2017, when hot, humid weather triggered brown patch, excessive irrigation was applied to promote brown patch. Disease severity was measured by visual ratings and digital image analysis; number of leaves in each plot that were infected was recorded using a grid. The mixed stand then showed less plot area affected by brown patch disease compared to the monostand of tall fescue.

Urban Lawn Microclimates Affect Reference Evapotranspiration

Grass reference evapotranspiration (ETo) obtained from weather stations in open locations is often used to estimate irrigation requirements of turfgrass in local or regional urban lawns. However, the environments of urban lawns are often altered by surrounding buildings, trees, etc., to form various microclimates that may alter evapotranspiration (ET). Our research, which placed weather stations in urban lawns and nearby open swards of turfgrass, revealed ETo was 41% lower in residential lawn microclimates than in nearby open turfgrass swards. Less ET within urban lawns than in nearby open swards suggests using standard historical weather data to estimate irrigation amounts in urban lawns (based on ETo) is problematic, because historical weather data is typically obtained from open areas such as local airports (Ley et al., 1996; Romero and Dukes, 2013). Consequently, the use of weather stations located onsite, or at least in an urban lawn within the same region, may improve estimates of lawn irrigation requirements.

Evaluating Large Patch-Tolerant and Cold Hardy Zoysiagrass Germplasm in the Transition Zone

A Zoysia japonica genotype, TAES 5645, that exhibited partial resistance to large patch in preliminary studies conducted by our collaborators at Texas A&M University, was used as a breeding parent at Texas A&M and crossed with 22 cold hardy zoysiagrasses, resulting in 2,858 progeny. These progeny were evaluated for cold hardiness and agronomic traits (establishment rate, overall quality, spring green up, leaf texture, and genetic color) in Manhattan, KS; West Lafayette, IN; and Dallas, TX; from 2012 to 2014. This report focuses on the Manhattan, KS, results. From this work, 60 progeny were identified for further evaluation in larger plots. In fall 2016, ‘Meyer’ (42% of plot area affected) had more large patch than all zoysiagrass progeny (0 to 23%). In spring 2017, Meyer had 33% large patch, higher than most progeny. Among this group of experimental zoysiagrasses, there appear to be promising progeny that have good winter hardiness, resistance to large patch, and improved turf quality characteristics. Data collection is ongoing.