21/03/2011

Despite the efforts of modern advertising... Adaptation, management and use of warmwarm--seasonseason turfgrasses ■ There is no such thing as a perfect turfgrass − And there never will be

■ There is no one grass that is best for all uses in all situations and at all locations Dr Donald S. Loch (University of Queensland & GeneGro Pty Ltd)

Choosing a turfgrass Management

■ Forget what is trendy ■ Choose a well adapted grass − Put promotional “information” into perspective − Easier to manage − Cheaper to manage − Better turf quality ■ Look at the use required (e.g. less weed invasion)

■ Understand your plant and work with it ■ Choose the best adapted grass for that use under the − ScienceScience--basedbased information climatic and soil conditions on your site (e.g. physiology, ecology, nutrition)

■ Concentrate on overcoming weaknesses − Strengths take care of themselves

Marketing ‘information’ The tropical challenge

■ Most warmwarm--seasonseason grass varieties from North America, ■ “...sales information is what gets repeated over and over etc, have not been developed for tropical conditions until it is accepted as fact - not always accurate” − Periods of heat, humidity, rain (irregular mowing), heavy cloud cover, low light, high pest & disease pressure − Mllitith4Monsoonal climates with 4-8thd8 month dry season (need good drought tolerance or unlimited irrigation)

■ Develop better adapted “local” varieties − e.g. most greensgreens--qualityquality bermudagrasses from about 30°30°latitude − NovotekTM developed in north Queensland tropics (17(17°°latitude)

■ Make greater use of Asian species and germplasm

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Outline of presentation Cynodon dactylon (bermudagrass)

■ Summarise strengths & weaknesses of the major species ■ Most widely used warm-warm-seasonseason turfgrass

■ Explore underlying factors leading to adaptation ■ Strengths − Climatic (temperature, drought, shade) − Spreads rapidly by stolons and rhizomes − Soils (salinity) − Good drought tolerance − Wear − Fair to good wear tolerance − Organoarsenate herbicides used to control most other grasses ■ Introduce some minor species and their attributes ■ Weaknesses ■ Turf quality vs. sod price − Few varieties adapted to tropical conditions − Poor shade tolerance − Morphological considerations − High N requirements − Varietal contamination (seed, vegetative survivors) ■ Quality assurance − Organoarsenate herbicides to be phased out in 2014 − An unnecessary expense or value for money?

Cynodon dactylon X transvaalensis Paspalum vaginatum (seashore paspalum) (hybrid bermudagrass)

■ MediumMedium--&& finefine--texturedtextured genotypes for fairways & greens ■ Former “niche” species well promoted over past decade

■ Strengths ■ Strengths − Vibrant green colour (the “wow” factor) − Sterile hybrids (do not set fertile seeds) − High salinity & waterlogging tolerance − Greater shoot densities than C. dactylon − Possible to plant a single variety wallwall--toto--wallwall − Can be mown shorter than C. dactylon − Finer textured turf than C. dactylon ■ Weaknesses − Expensive to manage in nonnon--salinesaline situations (competition) ■ Weaknesses − Limited range of herbicides (none for grass control) − Best adapted to warm temperate & subtropical conditions − Poor shade & drought tolerance − Need intensive management − Slow to recover from damage (scalping, drought thinning) − Genetically unstable (mixture of two different genomes) − Higher N requirements than promoted − Mutate vegetatively particularly when under stress − Risk of varietal contamination from seed − Finer stems do not mow as well as C. dactylon at higher levels − Disease susceptibility (e.g. dollar spot under low fertility)

Drought Weed invasion after drought

Scalping Scalping

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Sporobolus virginicus

Dollar Spot Dollar Spot Paspalum vaginatum

Rhizoctonia Large Patch Armyworm damage

Axonopus compressus Digitaria didactyla ((serangoonserangoongrass) (broadleaf carpetgrass)

■ MediumMedium--texturedtextured stoloniferous grass for low fertility sites ■ CoarseCoarse--texturedtextured grass for shaded roughs, parks, etc − Similar to Queensland blue couch & Swazi grass (Australia) − Called “cow grass” when mixed with Paspalum conjugatum, etc

■ Strengths ■ Strengths − TlTolerant of acid idif infertil e soil s − Tolerant of acid infertile soils − Good drought tolerance − Good shade & disease tolerance − Useful herbicide tolerance (e.g. fluazifop for other grasses) − Vegetative sod strengthened by bermudagrass contaminant − Moderate shade tolerance (Qld blue couch poor shade tolerance) (also gives better cool season growth) − Mows easily even if allowed to grow long (soft grass) ■ Weaknesses − Clippings stick together when mowing moist grass ■ Weaknesses − Poor ball lie (sits down among foliage) − Poor drought & wear tolerance − Susceptible to Fe deficiency after heavy rainfall − Susceptible to Fe deficiency after heavy rainfall (easy & cheap to remedy with FeSO4) − Low temperatures restrict growth more than other turf grasses − Fair wear tolerance

Zoysia spp. (zoysiagrass) Zoysia japonica (Japanese lawngrass)

■ Low maintenance grasses for fairways, tees & greens ■ CoarseCoarse--mediummedium textured genotypes for fairways & roughs − Originates from subtropical & temperate areas ■ Strengths − Low nutritional requirements ■ Strengths − Less mowi ng th an oth er grasses (l(slow grow th) − BlueBlue--greengreen colour (similar to serangoon grass) − Good drought tolerance − Fair shade tolerance − Few pests and diseases − Fair salinity tolerance − Tolerant of a wide range of herbicides (several for grass control) − Lower thatch development than Z. matrella − Good ball lie (sits up) − Tolerant of high strength soils − Highly resistant to wear ■ Weaknesses ■ Weaknesses − Slow growth (longer sod production cycle than for other species) − Susceptible to zoysia rust ((PucciniaPucciniazoysiae) zoysiae) − Sharpen mower blades more often (high silica content) − Tolerates temporary, but not permanent, waterlogging − Slow to recover from scalping

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Zoysia matrella ((ManilagrassManilagrass)) Temperature adaptation – Cynodon varieties

■ MediumMedium--&& finefine--texturedtextured genotypes for fairways & greens ■ Optimum temperature related to area of origin − More tropical in origin than Z. japonica ■ Stronger winter dormancy in genotypes from colder areas ■ Strengths − Bright green colour (varies with variety) ■ WtWarm temperat e (Me lbourne – 13. 4°ClC annual average ) − High shade tolerance − Victorian > NSW & Queensland varieties (VGA(VGA--RedlandsRedlands research) − High salinity tolerance − Tolerant of high strength soils ■ Subtropical (Brisbane – 20.520.5°°CC annual average) − Not affected by zoysia rust ((PucciniaPucciniazoysiae) zoysiae) − Queensland & NSW > Victorian varieties (Redlands research plots) − Close to the warmer limit for Cynodon hybrids ■ Weaknesses − Thatch development ■ Tropical (Cairns – 24.824.8°°C,C, Darwin – 28.128.1°°CC annual averages) − Also need tolerance of long periods of heavy cloud & low light − Slower green speeds than bermudagrass − Very few well adapted Cynodon varieties − Tolerates temporary, but not permanent, waterlogging − Local versions best (e.g. from ‘Greenlees‘Greenlees Park’)

Cazaly’s Stadium (Cairns) TIO Stadium (Darwin) – local version of ‘Greenlees‘GreenleesPark’ ––LegendLegend® from Victoria

Disease susceptibility

■ Disease tolerance related to area (climate) of origin – e.g. Bermudagrass accessions from dry (less humid) areas more susceptible to leaf diseases (UQ Australia-Australia-widewide germplasm collection) White leaf mycoplasmaBermudagrass smut

■ Disease control − Adds to management costs − Compromises turf quality

■ Greater emphasis on selecting new varieties for disease tolerance if available

Bermudagrass rust Zoysia rust

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Water use efficiency OR drought tolerance?

Paspalum vaginatum

■ Water use efficiency − Amount of water required to produce 1 unit of dry matter

■ Drought tolerance − What happens in absence of rain & irrigation (survival and how well it survives)

■ Total irrigation (e.g. desert conditions) − Water use efficiency Cynodon dactylon − Small savings in water use are possible

■ Strategic irrigation (e.g. irregular or seasonal rainfall) − Drought tolerance − Large savings in water use are possible by reducing frequency

Physiological drought tolerance – Yi Zhou (UQ)

Depth of rooting

■ Shade stress affects approx. 25% of turfgrass plantings − Trees & buildings in the landscape − Sports stadiums − Cloudy or hazy conditions

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Screening for salt tolerance Some “shady” facts

■ Measure Photosynthetically Active Radiation (PAR) − 400400--700700 nm wavelength band

■ 70% of daily radiation − 9:00am to 3:00pm (summer) − 10:00am to 2:00pm (winter) − Meeting light requirements for a turfgrass depends on when light is received, not just a fixed number of hours

■ Heavy dappled tree shade − c. 2020--40%40% of full sunlight

■ Building shade (e.g. elite sports stadiums) − c. 10% of full sunlight

Screening perennial turfgrasses for Salinity growth response over time salinity tolerance

„ TwoTwo--stagestage process (Rana MunnsMunns,, 1993) „ Three stages: – physiological drought (osmotic effect) for first 4 wk 1. establishment of vegetative material in pots – transition from physiological drought to toxic ion effects (salt(salt--freefree conditions) (4(4--66 wk after treatment) 2. transition to salinity treatments – toxic ion effects reduce DM production (progressively add salt over 11--33 wk period) (6+ wk) 3. experimental measurements over a 1212--wkwk period after reaching targeted salinity treatment levels „ Germination affected by physiological drought „ Determination of salinity tolerance focused on 88--1212 wk data – relative DM yield „ Perennial plant growth affected by both physiological (linear regression to determine EC at 50% control DM yield) drought and toxic ion effects over time – % leaf firing – root biomass (12(12--wk)wk)

Paspalum vaginatum ‘Sea Isle 2000’ Zoysia matrella ‘Diamond’ Growth response to salinity over time – C. dactylon FLoraTeXTM

Cynodon dactylon FLoraTeXTM Cynodon dactylon ‘CT-2’

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Wear tolerance

■ Two components of wear tolerance − Resistance to wear − Recovery from wear

■ Fortnightly wear (home(home--andand--away)away) less damaging than weekly wear in 3-3-yryr simulated wear trial − e.g. apply 30 passes per week or 60 passes per fortnight „ Traffic simulator – based on a standard US design – two rubber-rubber-coveredcovered rollers rotating at different speeds – causes scuffing of turf, minimal soil compaction

Factors & attributes contributing to wear tolerance

■ Higher Total Cell Wall constituents – TCW = lignin + Acid Detergent Fibre (ADF)

■ Higgetudestyher turf density

■ Tighter matting growth habit

■ Age of turf − 2nd year “decliners” need regular aggressive rejuvenation (e.g. elite stadiums) − 2nd year “improvers” should be left to mature (e.g. community sports fields) 8 Cynodon cultivars showing wear effects

‘Grand Prix’ ‘Princess’

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Legend® – no Primo Legend ® + Primo

Primo® ((trinexapactrinexapac--ethyl)ethyl)

■ Used to condition turf – Improve turf quality by tightening up sward – Reduce mowing requirements

■ Some varieties affected more than others Conquest® – no Primo Conquest ® + Primo

Effects of Primo ((trinexapactrinexapac--ethyl)ethyl) on 4 Cynodon varieties

Legend® Conquest®

Primo® ((trinexapactrinexapac--ethyl)ethyl)

■ Used to condition turf no Primo + Primo no Primo + Primo – Improve turf quality by tightening up sward – Reduce mowing requirements

‘Wintergreen’ TifSport® ■ Some varieties affected more than others

■ TwoTwo--stagestage effect on growth − Initial reduction in growth rate – Followed by a surge of pent-pent-upup growth unless re-re-appliedapplied

■ Wear damage may increase during growth reduction stage – Recovery from wear is restricted no Primo + Primo no Primo + Primo

Effects of Primo ((trinexapactrinexapac--ethyl)ethyl) on 4 Cynodon varieties

Legend® Conquest ®

Primo® ((trinexapactrinexapac--ethyl)ethyl)

■ Used to condition turf – Improve turf quality by tightening up sward – Reduce mowing requirements no Primo + Primo no Primo + Primo ■ Some varieties affected more than others ‘Wintergreen’ ‘Hatfield’ ■ TwoTwo--stagestage effect on growth − Initial reduction in growth rate – Followed by a surge of pent-pent-upup growth unless re-re-appliedapplied

■ Wear damage may increase during growth reduction stage – Recovery from wear is restricted

no Primo + Primo no Primo + Primo ■ Restrict prolonged or continuous Primo use to low wear situations Fortnightly wear

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Stenotaphrum secundatum Eremochloa ophiuroides (centipedegrass) (St Augustinegrass)

■ CoarseCoarse--texturedtextured stoloniferous grass for shaded lawns & roughs ■ CoarseCoarse--texturedtextured stoloniferous grass for lawns & roadsides − Low input use ■ Strengths − Good shade tolerance ■ Strengths − Fair to good wear tolerance in shade − Seed & vegetative sod available − Moderate fertility requirement (N) − Low mowing requirement (slow growing grass) − Competitive sward is relatively weed free − Low fertility requirement (N) − Useful herbicide tolerance (clethodim for other grasses) ■ Weaknesses − Moderate to poor drought tolerance ■ Weaknesses − High mowing requirement (fast growing grass) − Poor drought, shade, wear and waterlogging tolerance − Limited herbicide tolerance (none for other grasses) − Loss of colour during autumn-autumn-winterwinter − Early loss of colour in autumn/fall − Growth ceases almost completely during winter (including roots) − Disease susceptible under hot, humid conditions − Very slow to establish from seed (grey leaf spot – varietal susceptibility varies) (mix 1 in 20 with Axonopus fissifolius)

Axonopus fissifolius, syn. A. affinis Pennisetum clandestinum ((kikuyugrasskikuyugrass)) (narrowleaf carpetgrass)

■ CoarseCoarse--texturedtextured stoloniferous grass for low quality fairways, ■ CoarseCoarse--texturedtextured stoloniferous & rhizomatous grass for fairways, sports fields, parks & lawns race tracks, sports fields, lawns in cool highland tropical areas − Best adapted to subtropical areas (cf. Axonopus compressus) − Also warm temperate & cool subtropical (Australia, South Africa, etc)

■ Streng ths ■ Streng ths − Seed available − Seeded & malemale--sterilesterile (vegetative) genotypes − Relatively easy to establish − Fair drought tolerance − Tolerant of acid infertile soils − Recovers rapidly from wear − Mows easily (low thatch, soft grass) − TrinexapacTrinexapac--ethylethyl improves turf quality − Not as coarsecoarse--texturedtextured as Axonopus compressus ■ Weaknesses ■ Weaknesses − Poor resistance to wear − Poor wear tolerance − Poor shade tolerance − Moderate to poor shade tolerance − High fertility requirement (N) − Less tolerant of waterlogging than Axonopus compressus − Disease susceptible under hot, humid conditions

Paspalum notatum (bahiagrass)

■ Tough coarsecoarse--texturedtextured grass with shortly creeping shallow rhizomes for roadsides, sports fields, etc in subtropics & tropics

■ Strengths − High wear tolerance (except under horse use) − Good drought tolerance − Sown by seed − Established turf resists weed invasion − Low to moderate fertility requirement (N)

■ Pennisetum clandestinum ■ Weaknesses − MaleMale--sterilesterile kikuyu grass for lawns, sports fields, race tracks, etc − Shallow surface rhizomes easily damaged by horses − Seedling devedevelopmentlopment slow − Vegetative propagation only (produces no seed) − Summer flowering longlong--dayday plant − Denser, finer-finer-textured,textured, more uniform than seeded varieties − Profuse production of 4040--6060 cm tall seed heads (requires frequent mowing)

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Paspalum nicorae ((brunswickgrassbrunswickgrass))

■ CoarseCoarse--texturedtextured blue-blue-greengreen grass with deep shortly creeping rhizomes for roughs, roadsides, horse venues, etc

■ Strengths − Deep rhizomes not damaged by horses (recovers quickly after use) − Good drought tolerance − Sown by seed − Low to moderate fertility requirement (N)

■ Weaknesses − BlueBlue--greengreen leaf colour (if dark green is desired) ■ Paspalum notatum LowGroTM − Seedling devedevelopmentlopment slow − Summer flowering longlong--dayday plant − Short bahiagrass for roadside & sports field use − Production of 40-40-6060 cm tall seed heads (reduced under lower fertility) − 2020--3030 cm high seed heads (cf. 4040--6060 cm for ‘Pensacola’, etc)

Turf quality vs. Sod price

■ Price depends on – How fast production fields grow in (how often the fields can be harvested) – Ease of management (herbi cid es, e tc )

■ Quality depends on − Creating a tight mown surface

■ Stolon internode length ■ Paspalum nicorae ‘Blue Dawn’ − Long for rapid growgrow--inin − CoarseCoarse--texturedtextured blue-blue-greengreen leaves − Short for quality turf − Deep rhizomes protected from damage by horses − Adapted to subtropical & tropical areas

Linear regression – Internode length vs. Lateral spread Scatter diagram – Internode length vs. Branching (Stenotaphrum secundatum) (Stenotaphrum secundatum)

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New cultivar ... like a 33--leggedlegged barstool? Maintaining varietal integrity

■ Leg 1: Breed the cultivar ■ Care and vigilance – The easy bit ■ Don’t multiply your mistakes ■ Leg 2: Keep the integrity of the cultivar over the long term – Maintain a pure Foundation block as a source of planting material for larger production fields − Don’t lose the gains made through breeding – Don’t take planting material from larger production fields where the risk of − Avoid contamination by other varieties contamination is greater

■ Leg 3: Promote the cultivar effectively ■ Mow off seed heads within a week or so of emergence − Hollow advertising alone won’t work in the long term − Even 1% self-self-compatibilitycompatibility (e.g. Cynodon dactylon, Paspalum vaginatum) could lead to significant numbers of new genotypes establishing − Support with sound sciencescience--basedbased technical information

■ SpotSpot--sprayspray any contaminant plants found ■ Without all three “legs”? − Walk production fields regularly – Instability and failure

Take home messages

■ Consider the use required in relation to site characteristics – Climate, soils

■ Choose the best adapted species and variety – Cr iticall y assess all i nf ormati on, i ncl udi ng th e accuracy of promoti onal material as it relates to your conditions – Ask searching questions

■ Buy from a reputable source of clean planting material, not just seek the cheapest supplier

■ Management of a well adapted grass will be easier & cheaper, and should result in better turf quality

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