Sea Isle Research Articles

Tolerance of some warm-season turfgrasses to compaction under shade and sunlight conditions in Riyadh, Saudi Arabia.

We evaluated the compaction tolerance of some warm-season turfgrasses under shade and sunlight conditions in Riyadh, Saudi Arabia. Hybrid bermudagrass, Cynodon dactylon, cultivars ‘Tifway’ and ‘Tifsport,’ seashore paspalum (Paspalum vaginatum) and its cultivar ‘Sea Isle 2000’ were used. The study area was divided into two sections: one was exposed to sunlight and the other was maintained under 70% shade using a green plastic grille. Turfgrasses were planted using “sods” in beds containing a mixture of sand, silt, and peat moss (4: 1: 1, v/v). The soil was compacted using a locally-made 250 kg cylindrical roll, passing four times over the grown turfgrasses for 3 days/week. The results showed that plant height, leaf area, grass quality and color were decreased by compaction in both the shade and sunlight areas. Plant height in the shaded area with or without compaction was higher than in the sunlight area. Under compaction, ‘Sea Isle 2000’ was the shortest: 8.8 cm in the sunlight and 14.3 cm in the shade. For grasses grown in sunlight, compaction decreased grass height, and height was lowest (4.0 cm) for paspalum ‘Sea Isle 2000’ in January. In the shaded area, paspalum turfgrass retained its high quality (4.0) in April, May, and June. In the sunlight area, the grass quality was highest (4.0) in ‘Sea Isle 2000’ and the lowest (3.0) in ‘Tifsport.’ Paspalum turfgrass showed a higher color degree (4) than bermudagrass (2.5) in April, May, and June. Compaction also led to a decline in leaf area and fresh and dry weights of all grown turfgrasses. The grass density was high for paspalum turfgrasses, indicating that their resistance to compaction was greater than bermudagrasses. It can be concluded that the best compaction and shade-tolerant turfgrasses are ‘Sea Isle 2000’ and seashore paspalum.

A holistic approach to evaluating dune cores

As population density increases in coastal counties, shoreline stabilization efforts continue to gain momentum to protect infrastructure. Although protection techniques vary from ‘soft’ to ‘hard’ engineering, this paper focuses on a ‘hybrid’ technique utilizing geotubes as artificial dune cores. Previous literature presents conflicting results on the efficacy and potential impacts of dune cores on a beach-dune system. Here we evaluate and quantify the geomorphic impacts following dune core installation and investigate their economic feasibility. This was completed by comparing five case studies: Sea Isle City, NJ; Bolivar Peninsula, TX; Grand Isle, LA; Santa Rosa Beach, FL; and Nantucket Island, MA. An economic assessment was completed to compare dune core installation costs and repairs to alternative shoreline hardening methods. LiDAR data were used to compare dune slope, beach width, and beach volume between digital transects adjacent to and in front of the dune core installations. Digital elevation models (DEMs) were generated to provide a holistic view of geomorphic change and to assess whether erosion occurred landward of the dune core. Results indicate that dune cores are an economically feasible option compared to alternative methods. Limitations include UV exposure, wave influence, and heavy winds. Morphologically, beach width was 29.1% wider in adjacent transects and dune slope was 39.1% steeper in front of the dune core. Beach volume was lower by an overall average of 23.4%. The findings from this study suggest that dune cores are a ‘hard’ or ‘grey’ protection method.

Up-regulation of lipid metabolism and glycine betaine synthesis are associated with choline-induced salt tolerance in halophytic seashore paspalum.

Choline may affect salt tolerance by regulating lipid and glycine betaine (GB) metabolism. This study was conducted to determine whether alteration of lipid profiles and GB metabolism may contribute to choline regulation and genotypic variations in salt tolerance in a halophytic grass, seashore paspalum (Paspalum vaginatum). Plants of Adalayd and Sea Isle 2000 were subjected to salt stress (200-mM NaCl) with or without foliar application of choline chloride (1mM). Genotypic variations in salt tolerance and promotive effects of choline application on salt tolerance were associated with both the up-regulation of lipid metabolism and GB synthesis. The genotypic variations in salt tolerance associated with lipid metabolism were reflected by the differential accumulation of phosphatidylcholine and phosphatidylethanolamine between Adalayd and Sea Isle 2000. Choline-induced salt tolerance was associated with of the increase in digalactosyl diacylglycerol (DGDG) content including DGDG (36:4 and 36:6) in both cultivars of seashore paspalum and enhanced synthesis of phosphatidylinositol (34:2, 36:5, and 36:2) and phosphatidic acid (34:2, 34:1, and 36:5), as well as increases in the ratio of digalactosyl diacylglycerol: monogalactosyl diacylglycerol (DGDG:MGDG) in salt-tolerant Sea Isle 2000. Choline regulation of salt tolerance may be due to the alteration in lipid metabolism in this halophytic grass species.

Evaluation of bermuda and paspalum grass types for urban landscapes under saline water irrigation

ABSTRACTIn the arid regions, turfgrass cover is an integral part of landscape to protect the soil from erosion, enhance the aesthetic value, and improve the microclimate. The salinity and the scarcity of fresh water of the arid region are the major challenging factors in turfgrass production. Therefore, the need for salt tolerant turfgrass with functional quality is necessary to improve the turf performance. The detrimental effects of salinity include growth suppression, and lowered osmotic potential ultimately leading to firing of the leaf blades. In this context, the study was undertaken to determine the relative salt tolerance and growth response of turfgrass genotypes in order to recommend turfgrass cultivars that can tolerate high salinity irrigation and maintain excellent visual and functional qualities under United Arab Emirates (UAE) condition. The paspalum cultivars maintained the highest succulence percentage compared to the bermudagrass cultivars under enhanced salinity levels. The shoots count, fresh weight (FW), and dry weight (DW) were found highest in paspalum types. The chlorophyll a, chlorophyll b and the total chlorophyll content was found higher in bermuda grass types under high salinity levels. The bermudagrass cultivars showed significantly higher carotenoids, anthocyanins and proline compared to the paspalum types under salt stress condition. In the case of princess 77 and Yukon, an inherently high amount of proline was recorded which confirmed an increase up to 10,000 ppm and drastically declined beyond this concentration. Sea Dwarf paspalum and Sea Isle 2000 maintained uniformity in the proline level at all levels of salinity without significant variation. These findings point to the fact that both paspalum and bermuda types exhibited varied responses to different physiological and biochemical parameters under the saline conditions. Paspalum types have an edge over the bermudagrass in terms of shoot density, which is a potential factor in determining the high-quality turfs. Bermudagrass types can be applied in lower salinity conditions based on the responses as evidenced from the present results.

Performance of Annual and Perennial Ryegrass Mixtures for Winter Overseeding into Three Warm‐Season Turfgrass Species

Perennial ryegrass (Lolium perenne L.) is commonly overseeded into warm‐season turfgrasses during the fall to create a temporary, actively growing green cover. Excessive persistence of perennial ryegrass cultivars can increase management inputs and prolong the spring transitional period. A 2‐yr field study was conducted to investigate the effects of three ryegrass overseeding treatments on winter turf performance and spring transition rate for three warm‐season turfgrasses maintained at a golf fairway height. Treatments included improved turf‐type annual (Lolium multiflorum Lam. ‘Panterra’) and perennial ryegrasses (‘Premier II’ and ‘Peak’) sown into ‘Tifway’ hybrid bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt Davy], ‘Cavalier’ zoysiagrass (Zoysia spp. Willd.), or ‘Sea Isle 1’ seashore paspalum (Paspalum vaginatum Sw.). Visual assessments of turf quality were performed throughout the spring and early summer. Warm‐season and cool‐season plant density was assessed by measuring shoot counts, aboveground dry weight, and light entering the canopy each May and July. Annual ryegrass alone or within a perennial ryegrass mixture provided acceptable winter turf quality and hastened spring transition but did not consistently improve warm‐season turf recovery over perennial ryegrass alone in bermudagrass or seashore paspalum. Overseeding zoysiagrass resulted in unacceptable turf quality during the summer, regardless of overseeding treatment. In general, warm‐season turfgrass overseeding potential, as defined by spring transition and summer recovery, was ranked as follows: seashore paspalum > bermudagrass > zoysiagrass.

Seedhead Development of Three Warm‐Season Turfgrasses as Influenced by Growing Degree Days, Photoperiod, and Maintenance Regimens

Seedheads of warm‐season grasses can reduce the quality of golf course turf. The objectives of this research were to evaluate environmental conditions associated with seedhead production of three warm‐season turfgrasses maintained at various mowing heights (0.6 or 1.3 cm 2 d wk−1, 3.8 cm wk−1, or no mowing) over a 3‐yr period. Photoperiod was more influential on initial seedhead development of ‘TifGrand’ bermudagrass [Cynodon dactylon (L.) Pers. ×Cynodon transvaalensis Burtt‐Davy] and ‘Sea Isle 1’ seashore paspalum (Paspalum vaginatum Sw.) than calendar date or growing degree day (GDD) accumulation. Across all mowing heights, initial seedhead emergence began at 13.5‐h photoperiod in 2013 and between 13.8 and 14.2 h in 2014 and 2015. Calendar date and GDD had stronger correlations than photoperiod with seedhead production from January until summer for bermudagrass and seashore paspalum at all mowing heights except for the 0.6 cm 2 d wk−1. ‘Diamond’ zoysiagrass [Zoysia matrella (L.) Merr.] exhibited two major flushes of seedhead emergence that began with photoperiods of ∼12.8 h in fall and spring. The GDD on dates of initial seedhead emergence in spring and fall ranged from 167 to 196 and 1949 to 2230 (base model 10°C on 1 January), respectively, in all years across mowing regimens. Zoysiagrass seedhead production had the highest correlation with GDD in spring and with photoperiod in fall. Overall, photoperiod triggers initial seedhead emergence of bermudagrass and seashore paspalum, but GDD is more influential on seedhead production in summer. The emergence of Diamond zoysiagrass seedheads in spring was associated with calendar date, GDD, and photoperiod, but emergence in fall was dependent on photoperiod.

Competitiveness of Three Warm‐Season Turfgrasses during Spring Transition of Overseeded Turfs

Prior research on the topic of southern winter overseeding systems has been limited to the testing of management practices, seeding rates, and cool‐season grass genotypes. A desirable spring transition may also be dependent on warm‐season turfgrass species. A field study was conducted in College Station, TX, on overseeded (Lolium perenne L.) and nonoverseeded zoysiagrass (Zoysia spp. Willd. ‘Cavalier’), seashore paspalum (Paspalum vaginatum Swarz. ‘Sea Isle 1’), and hybrid bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt‐Davy ‘Tifway’] fairway turfs. The objectives of the experiment were to measure eight canopy attributes of the warm‐season species and to relate differences to competitiveness during the spring transition. Samples of canopies were collected in May, July, and September from each warm‐season turfgrass. Leaf area, leaf and shoot weight, and leaf and shoot counts were measured and used to calculate common plant canopy metrics such as leaf area index, leaf area ratio, specific leaf area, and leaf weight ratio. Grasses capable of extending vertical stems as an overtopping mechanism, as conveyed by lower leaf weight ratios, appear more competitive for light in a spring overseeded turf (e.g., hybrid bermudagrass) than grasses that invest significant resources towards leaf production (e.g., zoysiagrass). High shoot plasticity (change in canopy traits due to overseeding treatment) and efficient leaf area production (i.e., high specific leaf area) of seashore paspalum also contributed a competitive advantage during the spring transition period. This research demonstrates that canopy morphology can be a contributing factor to competitiveness of warm‐season turfgrasses in an overseeded turfgrass system.

Response of Seashore Paspalum Genotypes to Two Isolates of Sclerotinia homoeocarpa

Seashore paspalum (Paspalum vaginatum Schwartz) is a warm‐season turfgrass noted for its salt tolerance and is used on golf course fairways and greens. Dollar spot (Sclerotinia homoeocarpa F.T. Benn.) is an important disease of seashore paspalum, causing distinct silver dollar‐sized necrotic patches to form on the turf. Previous research by Flor et al. (2013) identified host plant resistance as a potential tool for dollar spot disease management using a single dollar spot isolate, UF0421. However, another isolate appeared more virulent in follow‐up experiments. With the intent of developing stronger selection pressure, disease response to these two characterized S. homoeocarpa isolates was compared in the current study under controlled environmental conditions using nine experimental lines of seashore paspalum and two commercial cultivars (‘SeaDwarf’ and ‘Sea Isle Supreme’) as controls. The second, putatively more virulent isolate consistently caused more damage to all 11 paspalum genotypes. An isolate × genotype interaction was not observed. Plant genotypes differed significantly in disease response, and all genotypes but one were consistent with the previous study. We successfully identified a more virulent strain of dollar spot. Using a more virulent strain will provide stronger selection pressure for development of resistance to dollar spot, allowing for clearer identification of resistant genotypes.

Changes In Antioxidant Enzyme Activity In Turfgrass Cultivars Under Various Saline Water Irrigation Levels To Suit Landscapes Under Arid Regions

ABSTRACTTurfgrass cover is an inevitable component in the urban landscapes of the United Arab Emirates. Tolerance to abiotic stress like salt, drought, and high temperature is a potential factor to be considered in the selection of turfgrass for the landscapes in the arid regions. Three Seashore paspalum genotypes, four Bermudagrass cultivars along with tall fescue as a control were screened for enzymatic changes under four different saline irrigation levels of 5,000, 10,000, 15,000, and 20,000 mg L−1 of salinity. Irrigation with potable water served as the control. Turfgrasses were maintained in a field experiment under factorial randomized block design for a period of two years under sustained saline conditions by working out the leaching fraction to maintain the precise level of salinity in each treatment throughout the experimental period. The activities of antioxidant enzymes such as superoxide dismutase (SOD), ascorbate peroxidase (APX), peroxidase (POD), polyphenol oxidase (PPO), and catalase (CAT) were assayed in each of the saline water treated turfgrass types. The SOD activity was found to be high in Yukon (bermudagrass) and Sea Dwarf paspalum. In the paspalum group, Salam and Sea Dwarf showed the highest SOD activity under saline condition. In Bermuda types, Yukon and SR 9554 showed the highest SOD activity compared to other bermuda types. Compared to other cultivars, Sea Isle 2000 (Paspalum type), SR 9554, and Yukon (Bermuda types) exhibited more APX activity without any significant differences among themselves. There was an elevated activity of POD initially, followed by gradual reduction upon increasing the salinity level. Salam cultivar maintained stable POD activity even at the elevated salinity levels. The paspalum types showed relatively high level of PPO activity compared to other types under salinity. Yukon cultivar showed a significantly higher activity of PPO when the salinity level was raised from 15,000 to 20,000 mg L−1. A significant increase with respect to CAT activity was exhibited in Sea Dwarf under elevated level of salinity. Saline water irrigation brought about a significant effect on the antioxidant enzyme systems to impart oxidative stress tolerance in turfgrass species.

Seashore paspalum in the Mediterranean transition zone: phenotypic traits of twelve accessions during and after establishment

The use of warm-season turfgrasses is consolidated in the transitional areas of Mediterranean countries and some field trials have provided information on the adaptability of seashore paspalum to Mediterranean environment. Nonetheless, little is known on the performance of the different commercial cultivars of <em>Paspalum vaginatum</em> in this climatic zone. Furthermore, considering the high degree of variability of this species, ecotypes have the potential to supply new plant material with desired turf characteristics. The research aimed at comparing growth characteristics and morphological traits of eight commercial cultivars of seashore paspalum (Platinum, Salam, SeaDwarf, Sea Isle 1, Sea Isle 2000, Velvetene, Marina and Sea Spray) and four ecotypes (CeRTES 101, CeRTES 102, CeRTES 103, CeRTES 104), during establishment and on mature turf grown in two Italian locations (Pisa and Palermo). Probably due to higher mean minimum temperatures a clear effect of location was recorded during the establishment year with fastest stolon growth rate and higher ground cover at 133 days after planting being registered in Palermo. Internode length and diameter, node density, horizontal stem density, turf quality and colour gave instead higher values in Pisa. On mature turf best colour ratings were of SeaDwarf and the ecotype CeRTES 104. The finest leaves were found in Sea Isle 2000 (1.5 mm) while the denser cultivars, and potentially the most wear resistant were Sea Isle 1, CeRTES 104, and Platinum. Top quality was scored for Sea Isle 1, Sea Isle 2000 and Platinum. Best performances for fall colour retention and spring green up were frequently associated with commercial cultivars. The relative ranking of the commercial cultivars for aesthetic and functional performance can be a tool for the decisions of turf managers while data of ecotype CeRTES 104 as to colour, shoot density and quality stimulate further research for the identifications of ecotypes with superior traits of visual quality and wear resistance.

Growth response and ion regulation of seashore paspalum accessions to increasing salinity

Seashore paspalum (Paspalum vaginatum Swartz) is an important warm-season turfgrass indigenous to tropical and coastal areas worldwide. The objectives of this study were to investigate the growth response and ion regulation of Chinese seashore paspalum germplasm under salinity stress. Twenty-seven seashore paspalum accessions and one check cultivar “Sea Isle 2000” were grown in solution culture in a glasshouse, with NaCl added to achieve salinities of 0 (control), 340 and 510mmol/L. Compared with the nonsaline controls, the salinity stressed accessions showed significantly increased leaf firing, decreased shoot growth, and an increase or decrease in root growth. Significant genetic variations in the leaf firing (LF), relative shoot weight (RSW) and relative root weight (RRW) were found among the different accessions, with coefficients of variation ranging from 19.54% to 37.84%. The P40 accession had the best salinity tolerance with little leaf firing under salinity stress, followed by Sea Isle 2000, P29 and P14. For the control, the average K+ concentration was 1161.69mmol/kg in the shoots and 383.73mmol/kg in the roots. Compared to the control, the salinity treatment showed that the K+ concentration treatment decreased in both the shoots and roots; however, the percentage of the reduction in the shoots was significantly lower (26.20%) than that in the roots (69.68%). The Na+ concentration was very low in both the shoots and roots of the seashore paspalum, with an average of 65.90mmol/kg and 39.50mmol/kg, respectively, under the treatment of nonsalinity. Compared to the nonsalinity control, the Na+ concentration greatly increased in both the shoots and roots; however, the percentage of the increase in the shoots was lower (15-fold) than in the roots (25-fold). The results indicate that taking up more of the K+, maintaining a high K+ concentration in the shoots and reducing the Na+ being transferred from the roots to the shoots could be the mechanisms for Na+ and K+ regulation for salinity tolerance in seashore paspalum.

Occurrence of chloramphenicol in cereal straw in north-western Europe

ABSTRACTTwo surveys are presented of straw analysed for naturally occurring chloramphenicol (CAP), a drug banned for use in food-producing animals. In the first study, CAP was analysed by LC-MS/MS and detected in 37 out of 105 straw samples originating from the Netherlands, France, the UK, Germany and Denmark. The highest level found was 6.3 µg kg−1, the average 0.6 µg kg−1 and the median 0.2 µg kg−1. The second study included a method comparison between ELISA and LC-MS/MS and a survey of CAP in cereal straw sampled at farms in all areas of Sweden. A total of 215 samples were screened by ELISA and a subset of 26 samples was also analysed by LC-MS/MS. Fifty-four of the samples contained more than 1 µg kg−1 CAP and the highest level found was 32 µg kg−1 (confirmed by LC-MS/MS). The highest contents of CAP in this study were allocated to the Baltic sea coast in the south-eastern part of Sweden (the county of Skåne and the Baltic Sea isle of Gotland). These results indicate a high incidence of CAP in straw in north-west Europe and have a severe impact on the enforcement of European Union legislation.

Freeze tolerance differs between two ecotypes of Paspalum vaginatum (Poaceae)

Morphological and physiological responses to freezing were evaluated in two ecotypes of the perennial turfgrass Paspalum vaginatum. Leaf extension rate, number of active meristems, leaf water potential and net photosynthesis were measured on plants of both a commercial cultivar, 'Sea Isle 2000', and a wild ecotype from the Flooding Pampa grasslands of Argentina. Plants were propagated by cloning, cultivated in pots, and examined during 18 consecutive days under two treatments: a non-frozen control treatment (15.5±7 oC) and a frozen treatment with two stages: Stage 1 with four hours of freezing stress for 10 nights (-5oC), and Stage 2 with 12 hours of freezing stress for eight nights (five nights at -5oC and three nights at -8oC). After these treatments, plants were returned to the outside environment to evaluate shoot injury and post-freezing recovery. Leaf water potential, net photosynthesis and leaf extension rate were significantly higher in the wild ecotype than in the commercial cultivar. Meristem density was reduced after freezing in both ecotypes, but was more pronounced in the commercial cultivar (98.5%) than in the wild ecotype (80%). Thus, the two ecotypes coming from different environments, exhibited different morphological and physiological responses to exposure to freezing temperatures.

Differential Behavior of Two Photosystem II Inhibitors in Seashore Paspalum

Seashore paspalum (Paspalum vaginatum Sw.) injury from triazines has limited the mechanisms of action used for postemergence (POST) weed control. Seashore paspalum is tolerant to a new Photosystem (PS) II inhibitor, amicarbazone (4‐amino‐N‐tert‐butyl‐4,5‐dihydro‐3‐isopropyl‐5‐oxo‐1H‐1,2,4‐triazole‐1‐carboxamide), but the physiological behavior attributed to differential tolerances from triazines has received limited investigation. The objectives of this research were to evaluate efficacy, absorption, translocation, and metabolism of 14C‐amicarbazone and 14C‐atrazine (1‐chloro‐3‐ethylamino‐5‐isopropylamino‐2,4,6‐triazine) in cultivar Sea Isle 1 seashore paspalum. In greenhouse experiments, atrazine treatments (560, 1120 or 2240 g a.i. ha−1) reduced shoot mass from the nontreated two times greater than amicarbazone treatments (98, 196, or 392 g a.i. ha−1). In laboratory experiments, foliar absorption of 14C‐amicarbazone increased from 1 to 7 days after treatment (DAT) but peak absorption of 14C‐atrazine occurred after 1 d. The 14C translocation from both herbicides was similar following root and shoot absorption. Seashore paspalum metabolized approximately two times more amicarbazone than atrazine after 1 d in foliar and root absorption experiments. From root absorption, seashore paspalum produced three metabolites of amicarbazone in roots and shoots at 1 and 3 DAT but only one metabolite of atrazine was found after 1 d. Three metabolites of atrazine were recovered at 3 DAT in shoots but only one metabolite was found in roots. Overall, faster metabolism in roots and shoots contributes to the greater tolerance of seashore paspalum to amicarbazone compared to atrazine.

Seashore Paspalum Tolerance to Amicarbazone at Various Seasonal Application Timings

Turfgrass injury from triazines has limited the use of photosystem II (PS II) inhibitors for weed control in seashore paspalum. Amicarbazone is a new PS II inhibitor with potential safety in seashore paspalum, but the effects of application timing on turf tolerance has received limited investigation. Field experiments were conducted in Griffin, GA to evaluate the tolerance of ‘Sea Isle 1’ seashore paspalum to amicarbazone applications in winter, spring, and summer. Seashore paspalum had minimal injury (< 5%) from amicarbazone treatments (98, 196, and 392 g ai ha−1) applied for annual bluegrass control in winter and spring. By 6 wk after treatment (WAT), amicarbazone at 392 g ha−1provided 78 and 90% annual bluegrass control in 2013 and 2014, respectively, and was similar to pronamide at 1,680 g ai ha−1. Amicarbazone at 196 g ha−1provided 71% control of annual bluegrass in 2014, but control was poor (< 70%) in 2013. Sequential amicarbazone applications at 98 g ha−1provided poor control in both years by 6 WAT. From six amicarbazone rates (up to 984 g ha−1) applied in summer, seashore paspalum required 510 and < 123 g ha−1for 20% turfgrass injury (I20) and 20% clipping reduction (CR20), respectively, whereas I20and CR20measured > 984 g ha−1for ‘Tifway’ bermudagrass. Overall, amicarbazone may be safely applied to seashore paspalum in winter, spring, and summer at rates and regimens evaluated. However, seashore paspalum may exhibit shoot growth inhibition up to 4 WAT, suggesting that end users should be cautious when using amicarbazone during active growth in summer.

First Report of Plant-Parasitic Nematodes on Seashore Paspalum (Paspalum vaginatum) in Barbados.

Seashore paspalum (Paspalum vaginatum Swartz) is a warm-season perennial turfgrass commonly used for golf courses that are grown in saline environments or using saline water for irrigation. However, seashore paspalum is also grown in non-saline conditions due to its low fertilizer and water requirements (2). In Barbados, on a newly constructed golf course, seashore paspalum 'Sea Isle Supreme' sprigs were imported from Georgia (United States) and were planted over 2006 and 2007 on greens, tees, fairways, and rough. Golf greens were constructed following the United States Golf Association Green Section (Far Hills, NJ) putting green guidelines. Tees and fairways were constructed using native soil. Two years after the grow-in, the putting greens began to exhibit irregular chlorotic patches, followed by gradual thinning and decline of turfgrass stand density in those areas. Additionally, turfgrass roots sampled from those symptomatic patches appeared to be abbreviated compared to non-symptomatic areas of the greens. A survey was conducted in May 2013 to determine if plant-parasitic nematodes were present coinciding with the observed symptoms, which were similar to those described in a previous report (3). Consequently, two samples were collected from each green with a total of four greens sampled. Each sample consisted of 20 soil cores (15 cm depth × 1.2 cm in diameter) from either areas of the greens showing symptoms or from non-symptomatic areas. Nematodes were extracted from 100 cm3 soil samples using a modified centrifugal-sugar flotation technique (4). No plant parasitic nematodes were present in any of the samples from the non-symptomatic areas. Three genera of plant parasitic nematodes were found in all the samples from the symptomatic areas: Helicotylenchus. Mesocriconema, and Pratylenchus. Nematode populations of these genera averaged 30, 60, and 200 nematodes per 100 cm3, respectively. Populations of the genera Helicotylenchus and Mesocriconema were below the action threshold levels for seashore paspalum used by the University of Florida Nematode Assay Laboratory (1). Currently, no threshold exists for Pratylenchus for seashore paspalum. Conversely, the genera Helicotylenchus. Mesocriconema, and Pratylenchus were found associated with the irregular chlorotic patches but not with the non-symptomatic areas. To our knowledge, this is the first report of plant parasitic nematodes associated with seashore paspalum maintained as putting greens in Barbados.

COMPARISON OF COMPOST AND A SANDY LOAM AS TURF UNDERLAY MATERIALS ON SALT-AFFECTED PARKLAND

Turfgrasses range from extremely salt sensitive to highly salt tolerant. However, the selection of a salt tolerant turf is not a 'silver bullet' solution to successful turf growth on salt-affected parklands. Interactions between factors such as cultivar, construction practices, establishment, and maintenance can be complex and should not be considered in isolation of one another. Taking this holistic approach, a study investigating cultivar evaluation for salt-affected sites also included a comparison of topsoil materials as turf underlay, as well as pre-treatment of the sod. The turf species and cultivars used in the study were: Cynodon dactylon, cultivar 'Oz Tuff (I) '; Paspalum vaginatum, cultivars 'Sea Isle 1 (I) ' and 'Velvetene (I) '; Zoysia matrella cultivar 'A-1 (I) '; and Zoysia japonica, cultivar 'Empire (I) '. The two underlay materials were compost (100%) or a sandy clay topsoil each applied above a coastal sand profile to a depth of 10 cm. Rooting depth or root dry weight did not significantly differ among turf cultivars. Compost profile treatment had significantly greater root mass than the topsoil among all turf cultivars. This higher root production was reflected by improved quality of all turf at the final evaluation. Turfgrass grown on compost had a higher normalised difference vegetation index (NDVI), regardless of whether full sod or bare-rooted turfgrass was used. The use of a quality underlay was paramount to the successful growth of the turf cultivars investigated. While each cultivar had superior performance in sub-optimal conditions, the key to success was the selection of the right species and cultivar for each situation combined with proper establishment and maintenance of each turf grass.

Influence of Turf Taxa and Insecticide Type on Survival of Geocoris spp. (Hemiptera: Geocoridae)

Effects of 7 concentrations of chlorpyrifos (Dursban 50W), halofenozide (Mach 2) and spinosad (Conserve SC) were tested on bigeyed bugs (Geocoris spp.: Heteroptera: Geocoridae) in bioassays with or without turfgrass as a potential moderating influence. Survival of bigeyed bugs was recorded at 1, 3, 7 and 10 d posttreatment. In a bioassay without turfgrass, the lowest chlorpyrifos dose of 62.5 ppm resulted in 100% adult bigeyed bug mortality; however, significantly more fifth-instar nymphs survived than first to fourth instars, whereas none of the adults survived. Spinosad at the recommended rate significantly reduced bigeyed bug density compared with the untreated check. Similarly, halofenozide influenced bigeyed bug survival only at the full-recommended rate in Petri dish assays. Effects of the same 6 concentrations of insecticides described above were studied on geocorids when 3 turfgrass genotypes, ‘Cavalier’ zoysiagrass (Zoysia japonica von Steudel and Z. matrella L. Merrill), ‘Sea Isle 1’ seashore paspalum (Paspalum vaginatum Swartz), and ‘TifSport’ bermudagrass (Cynodon dactylon L. × C. transvaalensis Burtt-Davy), were present. Chlorpyrifos affected survival of geocorids even at 62.5 ppm in all turfgrass genotypes evaluated at 1 or 3 d posttreatment. More bigeyed bugs survived on ‘Cavalier’ zoysiagrass than other turfgrass genotypes treated with chlorpyrifos. None of the turf-mediated residual concentrations of spinosad caused predator mortality. Insecticide-induced nontarget mortality is influenced by turfgrass genotype and may depend on mode of action of insecticide, type of host plant resistance and plant morphology and architecture.

Deficit Irrigation of Seashore Paspalum and Bermudagrass

We compared the responses of 16 mm tall ‘Tifsport’, ‘Tifway 419’, ‘Tifgreen 328’, and ‘MidIron’ bermudagrass [Cynodon dactylon (L.) Pers. × Cynodon transvaalensis Davy], and ‘SeaSpray’, ‘SeaDwarf’, and ‘Sea Isle 1’ seashore paspalum (Paspalum vaginatum Swartz) to variable rates of irrigation applied using a linear gradient irrigation system in the semiarid Southwest. Target irrigation levels were 100, 80, 60, and 40% (2009) and 100, 80, 70, 60, and 40% (2010) of standardized reference evapotranspiration (ETos). Actual water applied (including rainfall) was 100, 83, 66, and 49% of ETos in 2009 and 100, 83, 75, 66, and 49% in 2010. Canopy temperatures increased as much as 15°C, quality (rated on a scale of 1–9) decreased from values of 6 or greater in turf irrigated with 100% ETos to 1.25 to 4.35 in turf irrigated with 40% ETos in July and August 2010, while dry matter production declined between 1.3 and 15.8 g m−2 d−1. Water application rates required to maximize turfgrass quality ratings across all turfgrasses ranged from 75 to 83% of ETos. Lower application rates were required for acceptable quality turfgrass (with quality ratings ≥6.0) and ranged from 66 to 75% of ETos for bermudagrass, and 75 to 80% of ETos for seashore paspalum. Spring green‐up was delayed by deficit irrigation, approximately 2 wk with 80% ETos, 4 wk with 70% ETos, and 6 wk with 60% ETos. Bermudagrass, particularly MidIron, maintained higher quality ratings than seashore paspalum under accumulated water stress conditions.

Acute phase protein haptoglobin in blood plasma samples of harbour seals (Phoca vitulina) of the Wadden Sea and of the isle Helgoland

Haptoglobin (Hp) which is synthesized in response to infection, inflammation, trauma or toxicological damage is known as a major acute phase protein in numerous species. Quantification of the circulating concentration of this protein can provide an objective measure of the health status, but there is a lack of investigations on harbour seals. We investigated the Hp concentration in samples of 123 seals (Phoca vitulina) from the German and Danish Wadden Sea to study physiological ranges of Hp levels. Hp levels between 2002, the end of the phocine distemper virus epidemic (PDV), and 2007 were considered, and Hp concentrations between animals of different sex, ages as well as living areas were compared. Furthermore, as a case study, six animals from the open sea isle Helgoland were investigated in 2006. Influences on the health status of the seal population e.g. the PDV epidemic were reflected by increased Hp levels in North Sea seals in 2002. The results of the Wadden Sea seals showed no significant age-, sex-, or geographical area-related differences. Interestingly, for the seals of the open sea isle Helgoland higher Hp values were measured compared to the Wadden Sea seals. The present study demonstrates that Hp can be used as a diagnostic tool to monitor the health status of harbour seals.